Key-Controlled Safety Switch Locking Mechanism
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Solution Overview
Problem
Existing key switches have a high production cost due to a large number of components, are bulky, and can be inadvertently activated by tools other than the dedicated actuator, leading to safety and operational issues.
Innovation Solution
A key switch design featuring a driver cam and lock cams that rotate around different points, with engaging protrusions to prevent unauthorized rotation, reducing the number of components and simplifying assembly, while ensuring only the dedicated operating key can activate the switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If head lock members and coil springs are arranged in the direction of width to lock the driver cam, then the locking function is achieved, but the transverse dimension becomes large
Solution Approach 1:
The patent changes the arrangement direction of locking components from transverse (width direction) to longitudinal (thickness direction). The lock cam is positioned below the driver cam in the thickness direction, and the coil spring is arranged in the thickness direction between the lock cam and base structure, thereby reducing the transverse dimension while maintaining the locking function.
2Ease of operation
If the opening for inserting the operating key remains open all the time, then the ease of operation is improved, but foreign objects can enter and prevent effective locking
Solution Approach 1:
The patent introduces a key insertion detection member that acts as an intermediary between the operating key and the lock cam. When the key is inserted, this detection member moves and pushes the lock cam to rotate, disengaging the locking protrusion from the locking groove. This allows the opening to remain open for easy key insertion while preventing foreign objects from causing unauthorized rotation, as only the properly shaped key can move the detection member.
3Reliability
If multiple intermediate members and locking members are used to lock the driver cam, then the locking reliability is improved, but the number of components increases and production cost rises
Solution Approach 1:
The patent combines multiple locking components into a simplified integrated structure. The lock cam integrates the functions of multiple intermediate members and locking members into a single rotary component. The locking protrusion on the lock cam directly engages with the locking groove on the driver cam, eliminating the need for separate head lock members and reducing the total number of components while maintaining locking reliability.
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.