Wristwatch Switch Device Backlash Reduction via Dual Spring Segmentation
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Solution Overview
Problem
Conventional switch devices in electronic wristwatches experience instability and backlash during switching operations due to the resilient outward pressing of the rotating operation member by the coil spring, leading to unfavorable rotation and switching action.
Innovation Solution
A switch device design featuring a rotating operation member with a through-hole, a pressing operation member that moves within the through-hole, and two coil springs - one biasing the pressing operation member and the other the rotating operation member - to stabilize the switching action by preventing backlash and ensuring smooth rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pressing operation member is resiliently pressed outward together with the rotating operation member by the spring force, then the rotating operation member can be easily pulled outward, but the backlash of the rotating operation member occurs easily during rotation
Solution Approach 1:
The patent divides the single spring system into two separate spring systems: a first coil spring (30) that acts only on the pressing operation member (12), and a second coil spring (33) that acts only on the rotating operation member (13). This segmentation allows each spring to independently control its respective component, preventing the backlash issue while maintaining ease of operation. The first spring ensures the pressing operation member is properly positioned, and the second spring ensures the rotating operation member rotates smoothly without backlash.
2Ease of operation
If the pressing operation member rotates along with the rotating operation member, then the switching operation can be performed, but the switching action becomes unstable due to backlash
Solution Approach 1:
By separating the spring actions into two independent systems, the patent ensures that the pressing operation member and rotating operation member are each independently controlled. This prevents the backlash that occurs when a single spring controls both components, while still allowing the pressing operation member to rotate along with the rotating operation member for switching operations.
Solution Approach 2:
The patent changes the spring force parameters by introducing two different springs with different characteristics. The first coil spring (30) is optimized for controlling the pressing operation member's radial movement, while the second coil spring (33) is optimized for controlling the rotating operation member's rotational movement. This parameter differentiation resolves the backlash issue while maintaining switching capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a stable and improved switching operation by maintaining the rotating operation member's stability through the spring forces, preventing backlash, and allowing for smooth and favorable rotation, thereby enhancing the device's operability.
Implementation Method 1
a first coil spring which is arranged within the through-hole of the rotating operation member and biases the pressing operation member towards the one opening direction
Implementation Method 2
a second coil spring which is arranged within the through-hole of the rotating operation member and biases the rotating operation member towards the one opening direction
Data Source
AI summary
A switch device includes a rotating operation member in which a through-hole is formed in an axial direction; a pressing operation member which is movable within the through-hole of the rotating operation member and press-operable from one opening of the through-hole. The pressing operation member is provided so as to rotate integrally with the rotating operation member, when the rotating operation member rotates. A first coil spring is arranged within the through-hole of the rotating operation member and biases the pressing operation member outwardly in the axial direction. A second coil spring is arranged within the through-hole of the rotating operation member and biases the rotating operation member outwardly in the axial direction.