Push-piece Winding Button Control Device for Portable Objects
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Solution Overview
Problem
Existing push-piece winding button control devices for portable objects, such as wristwatches, face challenges due to the need for large diameter holes in the case middle to accommodate the control stem, making them difficult or impossible to implement, especially when machining the cam path increases the thickness of the portable object.
Innovation Solution
The solution involves transferring the position indexing mechanism, typically comprising cam paths and an elastic member, from the control stem to a separate position indexing plate, allowing the control stem to have a reduced diameter and maintaining the same orientation, thus avoiding increased thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the cam path is machined in the control stem, then the positioning function is achieved, but the control stem diameter must be relatively large
Solution Approach 1:
The patent divides the positioning system into two separate components: the control stem and the position indexing plate. The cam path is machined on the plate rather than the stem, allowing the stem to have a reduced diameter while the plate provides the positioning function through its cam profile and follower mechanism.
Solution Approach 2:
The cam path feature is extracted from the control stem and transferred to a separate position indexing plate. This extraction allows the control stem to be simplified and reduced in diameter, while the plate independently provides the positioning functionality through its cam profile.
2Length of stationary object
If the control stem diameter is reduced, then the thickness of the portable object is reduced, but the positioning reliability may be compromised
Solution Approach 1:
The position indexing plate acts as an intermediary component between the control stem and the housing. It transfers the positioning function from the stem to the plate, allowing the stem to be thin while the plate provides robust positioning through its cam profile and elastic follower mechanism.
Solution Approach 2:
The positioning function is moved from the radial dimension (stem diameter) to the axial dimension (plate thickness). The cam profile on the plate provides positioning in the axial direction, allowing the stem diameter to be reduced without compromising positioning reliability.
3Reliability
If the cam follower pressure on the ramp profile portion is increased, then the stem return to stable position is more reliable, but the force required to press the button increases
Solution Approach 1:
The cam profile is designed with varying slopes to dynamically adjust the force characteristics. The ramp portion has a specific slope that provides sufficient return force while the recess portions provide stable positions with lower holding forces, creating a dynamic force profile that ensures reliable return without excessive button press force.
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
This approach enables reliable stem positioning with a smaller diameter control stem, providing a click sensation during transitions and reducing the thickness of the portable object, making it suitable for use in horology without the need for large diameter holes.
Implementation Method 1
The cam follower is mounted inside the frame and is arranged to be elastically returned against the cam path
Implementation Method 2
The at least one cam path with which the at least one cam follower cooperates, is formed in a position indexing plate
Data Source
AI summary
A push-piece winding button control device is for a portable object of small dimensions. This device includes a pivoting control stem axially movable between at least a transitory first position and a stable second position. The device further includes a position indexing plate arranged to be integral in translation with the control stem, while keeping the same orientation relative to the frame. The device also includes a cam follower arranged to cooperate with a longitudinal cam path formed in the position indexing plate. The cam path includes a recess defining the stable position of the control stem, and a ramp-shaped profile portion which rises from the recess towards the transitory position.