Axial Spring Coaxial Wheel Disengagement Mechanism
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Solution Overview
Problem
Conventional coaxial wheel systems for watch movements are bulky, complex, and delicate due to radial spring coupling, limiting the number of jumping steps and requiring complex spring designs with thin sections, which complicates manufacturing and adaptability to different angular distances.
Innovation Solution
A disengageable coaxial wheel device with an axial spring mechanism, utilizing hollow and protruding elements to apply elastic force, allowing precise and reliable operation with a compact design, enabling easy adjustment and manufacturing, and accommodating various pitch variants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a radial spring coupling system is used for coaxial wheels, then the wheels can be coupled together, but the device becomes bulky and complex with limited jumping steps
Solution Approach 1:
The invention transitions from a radial spring arrangement to an axial spring arrangement, changing the dimension in which the elastic force is applied. The spring now acts in the axial direction between two coaxial wheels, with the elastic force vector parallel to the rotation axis rather than radial. This dimensional change simplifies the spring geometry to essentially flat or thin disc shapes, reducing device complexity and bulk while maintaining reliable wheel coupling.
Solution Approach 2:
The invention changes the direction parameter of the elastic force from radial to axial. By reorienting the spring force vector to act axially between the wheels rather than radially outward, the spring design becomes simpler (essentially flat or thin disc shapes) while achieving the same coupling function. This parameter change directly reduces device complexity and allows for more jumping steps within the same spatial envelope.
2Force
If a radial spring with lobes is used to provide elastic properties, then the required elastic force is achieved, but the device occupies a large area and becomes bulky
Solution Approach 1:
The spring design moves from a radial configuration with lobes extending outward (occupying large area) to an axial configuration where the spring is essentially a flat or thin disc with the elastic element oriented along the rotation axis. This dimensional reorientation allows the same elastic force to be generated within a much smaller radial footprint, directly reducing the area occupied by the spring mechanism.
Solution Approach 2:
The axial spring is described as being in the form of an essentially flat or thin disc, utilizing thin film geometry to provide the required elastic properties. This thin disc configuration with axial elastic arms generates the necessary elastic force while occupying minimal area, contrasting with the bulky radial spring with lobes.
3Force
If the spring has a complex shape with thin sections, then the required elastic properties are achieved, but manufacturing becomes complicated and delicate
Solution Approach 1:
By changing the orientation parameter of the spring from radial to axial, the geometry simplifies from complex shapes with thin sections to essentially flat or thin disc shapes. This parameter change makes the spring much easier to manufacture using standard stamping or disc-forming processes, eliminating the manufacturing complexity and delicacy associated with radial springs featuring lobes and thin sections.
Solution Approach 2:
The axial spring utilizes a flat or thin disc geometry that can be manufactured using simple stamping or forming processes from sheet material. This thin film approach provides the required elastic properties through the disc's overall geometry and material selection rather than through complex thin-section features, greatly simplifying manufacturing.
4Ease of operation
If the diameter of the third wheel is limited by spring mounting space, then the radial spring can be accommodated, but the number of jumping steps for a complete revolution is limited
Solution Approach 1:
The invention eliminates the need for a third wheel by applying the spring axially between two coaxial wheels. This dimensional change in force application allows the elastic coupling to be achieved without the intermediate third wheel that defined discrete angular positions in radial spring systems. The result is a simpler two-wheel structure with potentially more jumping steps achievable within the same diameter constraints.
5Ease of operation
If a clutch release torque is applied to overcome radial elastic force, then wheel disengagement is achieved, but the system requires high reaction torque and becomes less adaptable to different angular distances
Solution Approach 1:
By changing the direction of the elastic force from radial to axial, the torque generation mechanism changes fundamentally. The axial spring generates torque through axial displacement rather than radial force, allowing for easier disengagement and greater adaptability to different angular distances between jumping steps. The axial configuration decouples the spring geometry from the wheel diameter constraints, enabling easier adaptation to various pitch requirements.
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 axial spring mechanism provides a robust, reliable, and compact solution for coaxial wheel systems, allowing precise control of angular positions and increased jumping steps without the complexity of radial spring systems, enhancing manufacturing ease and adaptability.
Implementation Method 1
The spring is configured to apply an elastic force in the axial direction
Data Source
Figure 1
Figure 2a~2b
Figure 2c
AI summary
A disengageable coaxial wheel device (10) for a watch movement, comprising an input wheel (12), an output wheel (16), a hub (14), and a jumper mechanism (18) including a spring (20) and positioning elements (22) defining a number of discrete angular positions of the input wheel relative to the output wheel about an axis of rotation (A). The positioning elements include hollow elements (24) and protruding elements (26), the spring being configured to apply an elastic force pushing the protruding elements against the hollow elements to lock the rotating wheels together under a disengagement torque. The protruding and hollow elements extend in the axial direction, and the spring is configured to apply an elastic force in the axial direction.