Interchangeable Lock Core with Offset Cam and Snap-Fit Housing
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Solution Overview
Problem
Existing lock core assemblies are vulnerable to tampering, costly to manufacture, and require threaded interfaces, which can be damaged during installation, and are not easily rekeyed without replacing the entire assembly, especially when trying to achieve a flush mount on narrow doors for enhanced security.
Innovation Solution
A flush-mounted lock core assembly with a non-cylindrical housing that uses an offset cam mechanism and interlocking dogs for secure attachment to a latch assembly without threads, allowing for one-sided installation and easy replacement of thumb-turn components using a special key, enhancing security and versatility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threaded interface is used to secure the lock core assembly to the latch assembly, then the assembly can be securely attached, but the threads can be damaged during installation and the housing requires extensive machining increasing manufacturing cost
Solution Approach 1:
The patent replaces the threaded mechanical connection system with a snap-fit mechanism featuring radial tabs that engage with corresponding slots in the latch assembly. This substitution eliminates the need for extensive machining of threads while providing secure attachment through elastic deformation of the housing material during installation.
Solution Approach 2:
The patent changes the physical state of the housing material by incorporating elastic properties, allowing the radial tabs to deform during installation and then maintain a secure locked position. This parameter change from rigid to elastic behavior enables tool-free installation while maintaining attachment security.
2Ease of manufacture
If a cylindrical housing is used for the lock core assembly, then the assembly can be easily manufactured, but it is vulnerable to forced twisting by intruders to break it free from the latch assembly
Solution Approach 1:
The patent transitions from a symmetric cylindrical housing to an asymmetric elongated housing with a specific orientation. This asymmetric shape prevents forced twisting by intruders while maintaining ease of manufacture through standard elongated profile extrusion or molding processes.
3Ease of operation
If the lock core assembly extends beyond the outer surface of the door, then installation is simpler, but the assembly is exposed to outside lateral forces reducing security
Solution Approach 1:
The patent moves the lock core assembly from a protruding configuration into the plane of the door surface by extending the housing elongation in the direction of door thickness. This dimensional change allows the assembly to be recessed into the door, protecting it from lateral forces while maintaining installation simplicity through the snap-fit mechanism.
4Reliability
If a lever component partially blocks the opening that receives the lock core assembly, then the locking train can function, but the housing must be formed into two sections increasing part costs and installation complexity
Solution Approach 1:
The patent positions the locking train components in advance during latch assembly manufacturing, creating a clear unobstructed opening pathway. This preliminary action allows the elongated housing to be installed as a single piece without requiring segmentation, reducing part costs and installation complexity while maintaining locking train functionality.
Data Source
AI summary
An interchangeable core assembly for a lock core assembly capable of being flush mounted in a door including a housing, a lock insert mounted in the housing, a lock core mounted in the housing adjacent to and cooperative with the lock insert, a thumb-turn assembly mounted in the non-cylindrical housing coaxial with the lock core, a first offset cam mounted on the thumb-turn assembly for rotation therewith, and a second offset cam mounted on the lock core for rotation therewith. The barrel of the lock core assembly is unobstructed by locking train components such that the lock core assembly extends completely through the latch assembly when installed therein. The lock core assembly is secured to the latch assembly without threads and a means to remove/replace the thumb-turn component is provided.