Cylinder Lock Tailpiece Anti-Rotation Coupling
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Solution Overview
Problem
Cylinder lock assemblies are vulnerable to breaches when the connection between the cylinder plug and tailpiece is forcibly disconnected, allowing the tailpiece to rotate independently and bypass the lock without the proper key.
Innovation Solution
A rotational coupling element, such as anti-rotation legs or pins, is integrated into the cylinder lock assembly to ensure that the tailpiece cannot rotate about the cylinder plug's longitudinal axis independently, even if the conventional connection is breached, by extending from the tailpiece into offset holes or slots in the cylinder plug.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the tailpiece is connected to the cylinder plug by conventional fasteners (screws, bolts), then the assembly is easy to manufacture and assemble, but the connection can be forcibly breached by inserting a rigid object through the keyway and applying impact force
Solution Approach 1:
The connection system is divided into two independent parts: conventional fasteners (screws or bolts) that provide easy assembly, and a separate rotational coupling element (anti-rotation leg or pin) that provides security against forced breach. This segmentation allows each component to optimize its function without compromising the other.
Solution Approach 2:
The rotational coupling element is pre-installed into the cylinder plug before the tailpiece is attached. This preliminary placement ensures that even if the conventional fasteners are breached, the tailpiece cannot rotate independently because the anti-rotation leg or pin is already positioned to prevent such rotation.
2Ease of operation
If the tailpiece can rotate independently of the cylinder plug, then the lock can be bypassed without a key by rotating the tailpiece to retract the deadbolt, but the lock security is compromised
Solution Approach 1:
The rotational coupling element is positioned asymmetrically within the cylinder plug, with the anti-rotation leg or pin extending into an off-center hole or slot. This asymmetric positioning creates a mechanical constraint that prevents the tailpiece from rotating independently while allowing normal keyed operation to function properly.
Solution Approach 2:
The rotational coupling element is installed in advance during assembly, establishing the rotational constraint before the lock is put into service. This preliminary action ensures that the security feature is already active and cannot be bypassed through subsequent forced rotation of the tailpiece.
3Reliability
If a rotational coupling element is added to prevent independent tailpiece rotation, then the lock security against bypass is improved, but the device complexity increases
Solution Approach 1:
The rotational coupling element is merged with the existing tailpiece structure, where the anti-rotation leg or pin is formed as an integral part of the tailpiece assembly. This merging approach adds the security function without requiring a completely separate mechanism, thereby limiting the increase in overall device complexity.
Data Source
AI summary
The present application relates to lock assemblies that provide a secondary coupling point, utilizing an anti-rotation pin or extended tailpiece leg or other method, which rotationally couples the tailpiece to the cylinder plug, thereby preventing rotation of the tailpiece independently of the cylinder plug. Therefore, a tailpiece within a bolt cam or other actuator used to withdraw a bolt or unlock a lockset cannot be rotated after the tailpiece connector connecting the tailpiece to the cylinder plug has been forcibly removed, severed, or destroyed.