Double Cylinder Lock Rotator Design Against Picking and Snapping
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Solution Overview
Problem
Cylinder locks are vulnerable to picking and snapping, allowing unauthorized access to the cam mechanism, which can be actuated to unlock the door.
Innovation Solution
A cylinder lock mechanism featuring dual plungers with axial positions and engagement apertures that prevent rotation unless a correct key is inserted, and includes a break point and abutment members to secure the rotator against tampering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional cylinder lock with a single locking mechanism is used, then the device complexity is low, but the lock can be picked or snapped, allowing unauthorized access to the cam mechanism
Solution Approach 1:
The lock is divided into two independent but interconnected locking mechanisms (first and second plungers) that operate on opposite sides of the door. Each plunger has its own keyhole and locking sequence, creating segmented security layers that must both be bypassed to compromise the lock
Solution Approach 2:
The first and second plungers are nested within the same lock body, with each plunger containing its own engagement member that interacts with the shared rotator and cam mechanism. This nested structure allows independent locking actions to converge on a common unlocking mechanism
2Reliability
If a break point is added to the cylinder to control where it snaps, then access to the cam is partially prevented, but the cam can sometimes still be accessed after the cylinder is broken
Solution Approach 1:
The abutment member is pre-positioned within the lock body to block the cam mechanism before any snapping or breaking occurs. This preliminary protective measure ensures that even if the cylinder is broken or snapped off, the abutment member remains in place to prevent access to the cam
Solution Approach 2:
The abutment member acts as an intermediary protective element between the cylinder and the cam mechanism. It provides an additional layer of security that mediates between the external attack (snapping) and the protected component (cam), preventing direct access even when the primary protection (cylinder) is compromised
3Reliability
If the first and second plungers are engaged with the rotator to prevent rotation, then security is enhanced, but the engagement members must be precisely positioned in engagement apertures
Solution Approach 1:
The engagement members and engagement apertures are designed with asymmetric geometries that provide tactile feedback and mechanical guidance during the locking and unlocking process. The asymmetric shapes ensure proper alignment while providing feelable engagement points that reduce the precision required during manufacturing and operation
4Reliability
If dual plungers with multiple axial positions are used, then the locking mechanism becomes more secure against picking, but the ease of operation with a key is reduced
Solution Approach 1:
The key is designed to merge the functions of actuating both plungers into a single insertion and rotation action. The key's geometry allows it to simultaneously engage with both plungers, pushing them to their disengaged positions through one unified motion, thereby maintaining ease of operation despite the dual-plunger complexity
Data Source
Figure 1B
Figure 1A~1C
Figure 2A~2B
AI summary
A double cylinder lock (500) comprising a body (110) and first and second key operated cylinders (120a,120b) each with a plunger (600a,600b) engageable with a rotator (700). When no key is inserted into first and second cylinders the first and second plungers are in a first axial position, wherein they both engage the rotator and at least one of the plungers is engaged with the body preventing rotation of both cylinders and rotator. When a key is inserted into a cylinder the plunger is axially moved to a second axial position permitting rotation of the rotator. The first and second plungers each comprise an engagement member (690) that extends into one of a plurality of engagement apertures (720) on the rotator. The plurality of engagement apertures comprises an interference engagement aperture (730a) that is redundant for actuation of the door mechanism.