Compact Key Switch Lock Cam Mechanism Against Unauthorized Rotation
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Solution Overview
Problem
Existing key switches for door lock applications are complex, costly to produce, and prone to unauthorized activation due to their large size and multiple components, which allows foreign objects to interfere with the locking mechanism.
Innovation Solution
A key switch design featuring a driver cam and lock cams that rotate around different points, with engaging protrusions and arcuate surfaces to prevent unauthorized rotation, reducing the number of components and assembly complexity while ensuring secure operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If head lock members and coil springs are arranged in the width direction to lock the driver cam, then the locking function is achieved, but the transverse dimension becomes large
Solution Approach 1:
The patent repositions the locking mechanism from the width direction to the thickness direction. The driver cam is locked by engagement with the base structure through its thickness dimension rather than through width-direction components, thereby achieving reliable locking while minimizing the transverse dimension of the operating part.
2Ease of operation
If the opening for inserting the operating key remains open all the time, then ease of operation is improved, but foreign objects can enter and interfere with the locking mechanism
Solution Approach 1:
The patent introduces an operating rod as an intermediary mechanism. The operating rod transmits the rotational motion from the driver cam to the contact points, allowing the key opening to remain closed while still enabling key insertion and operation through the rod's mechanical transmission function.
3Reliability
If multiple components are used in the operating part, then the locking function is reliable, but the number of components increases production cost
Solution Approach 1:
The patent merges multiple functions into fewer components. The driver cam integrates both the locking function (through engagement with the base structure) and the operating function (through rotation to move the operating rod). The operating rod combines the functions of transmitting motion and actuating the contact points, thereby reducing component count while maintaining reliable locking.
4Ease of manufacture
If the operating part is made compact with fewer components, then production cost is reduced, but assembly complexity may increase
Solution Approach 1:
The patent segments the operating part into distinct functional modules: the driver cam module (with integrated locking), the operating rod module (with return spring), and the contact points module. This segmentation allows each module to be assembled independently and then combined, reducing overall assembly complexity despite the compact design and fewer components.
Data Source
AI summary
A key switch has a switch part and an operating part. The switch part is activated to switch contact points as an operating key is inserted. The operating part includes a driver cam that rotates as it is pushed by the operating key and to activate the switch part and a plurality of lock cams configured to directly lock the driver cam in a normal condition when the operating key is pulled out of the operating part and to rotate as it is pushed by the operating key so as to release the driver cam from its locked condition. The key switch may further include lock cam holder for holding the lock cams in the normal condition when the operating key is pulled out.