Coupling Device Sliding Gear Watch Mechanism Wear
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Solution Overview
Problem
Existing watch mechanism coupling devices face issues such as significant wear and jamming due to non-concentric pivoting axes, and slow switching between engagement configurations, which affect the efficiency and reliability of automatic winding and time-setting mechanisms.
Innovation Solution
A bistable elastic bar is used, anchored at both ends and working in buckling, to slavage the mobile support's position, allowing instantaneous switching between stable configurations and reducing wear by acting as a spring to return the slider to its stable position, eliminating the need for complex fixing mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the mobile support is arranged to pivot around an axis not concentric with the return wheel axis, then the coupling device can achieve engagement and disengagement between the return wheel and toothed mobile, but significant wear and jamming occur due to variations in meshing depth
Solution Approach 1:
The mobile support is transformed from a rigid pivoting structure to a dynamic system using a bistable elastic bar that can switch between two stable configurations. This dynamic switching mechanism allows the return wheel to engage and disengage from the toothed mobile while maintaining constant meshing depth, eliminating wear and jamming issues associated with non-concentric pivoting.
Solution Approach 2:
The invention changes the fundamental parameter of the mobile support from fixed geometric positioning (non-concentric pivot) to variable positioning controlled by elastic bar buckling states. The bistable elastic bar allows the mobile support to occupy two distinct positions corresponding to engagement and disengagement states, while maintaining optimal meshing conditions in each state.
2Device complexity
If a traditional pivoting mechanism is used for the mobile support, then the structure is simple, but the switching time between engagement configurations is not negligible
Solution Approach 1:
The bistable elastic bar utilizes elastic buckling - a form of mechanical instability - to enable rapid switching between configurations. When triggered, the elastic bar snaps from one stable state to the other in a fraction of the time required for gradual pivoting, significantly reducing switching time while maintaining structural simplicity.
Solution Approach 2:
The elastic bar operates in discrete periodic states (two stable configurations), allowing the mechanism to switch between engagement and disengagement positions rapidly. This periodic bistable behavior eliminates the continuous gradual movement of traditional pivoting mechanisms, reducing switching time.
3Use of energy by stationary object
If the return wheel is constantly engaged with the pinion, then continuous power transmission is achieved, but the time required for the clutch to switch configurations causes the wheel to return backwards requiring a pawl to prevent backward movement
Solution Approach 1:
The invention extracts and eliminates the pawl and spring mechanism by achieving truly instantaneous switching through the bistable elastic bar. The rapid switching capability ensures the return wheel is disengaged from the toothed mobile fast enough to prevent any backward movement, making the anti-reverse mechanism unnecessary.
Solution Approach 2:
The bistable elastic bar enables the switching action to rush through so quickly that the return wheel effectively skips the disengagement phase, preventing any backward rotation. This ultra-fast switching eliminates the need for mechanical anti-reverse devices like pawls.
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 solution significantly reduces wear, enables almost instantaneous switching, and prevents jamming by ensuring smooth engagement and disengagement of gears, enhancing the reliability and efficiency of watch mechanisms.
Implementation Method 1
A section of the bistable elastic bar is further fixed to the movable support, so that the position of the latter is controlled by that of the section of the bistable elastic bar
Implementation Method 2
A bistable elastic bar held by its two ends between two anchor points and working in buckling
Implementation Method 3
reducing wear by acting as a spring to return the slider to its stable position
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The coupling device for a kinematic chain with a toothed component (76) comprises a gearbox (64, 66) and a movable support (68) on which the gearbox is rotatably mounted. The gearbox is part of the kinematic chain and is permanently connected to another element (74) thereof. The support (68) is movable between a first position in which the gearbox (64, 66) meshes with the toothed component (76) and a second position in which the gearbox is disengaged from the toothed component. The coupling device further comprises a bistable elastic bar (78) held at both ends between two anchor points and subjected to buckling in a plane perpendicular to the axis of rotation of the gearbox (64, 66). A section of the bistable elastic bar (78) is fixed to the movable support (68), such that the position of the latter is controlled by that of the section of the bistable elastic bar.