Watch Constant Force Device with Nested Spring and Cam Control
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Solution Overview
Problem
Existing constant-force devices in watches experience significant power loss in the transmission path from the primary spring accumulator to the secondary spring accumulator, resulting in a relatively small torque on the cam disk, which necessitates a high output force from the primary spring accumulator to achieve sufficient torque.
Innovation Solution
A design where the seconds shaft is driven by the secondary spring accumulator, carrying the cam disk and a fourth wheel that directly drives the oscillating system, along with a stop wheel and rocker mechanism, reduces power loss and increases torque efficiency by minimizing friction and optimizing power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a transmission path is used from the primary spring accumulator to the secondary spring accumulator, then the power transfer is achieved, but significant power loss occurs and torque on the cam disk becomes relatively small
Solution Approach 1:
The invention extracts and eliminates the intermediate transmission components (third wheel, third wheel shaft) from the power transmission path. The secondary spring accumulator is directly coupled to the barrel (primary spring accumulator), removing the transmission path that caused power loss and small torque on the cam disk.
Solution Approach 2:
The invention implements a nested structure where the secondary spring accumulator is positioned inside the barrel (primary spring accumulator). The inner circumference of the barrel engages directly with the outer circumference of the secondary spring accumulator, creating a compact nested arrangement that eliminates intermediate transmission components while maintaining efficient power transfer.
2Force
If the primary spring accumulator is designed with high output force to achieve sufficient torque, then torque requirement is met, but the device complexity and effort increase
Solution Approach 1:
The invention removes the complex intermediate transmission mechanism (third wheel, third wheel shaft, and their mounting structures) from the device. This extraction of unnecessary components directly reduces device complexity while maintaining sufficient torque through direct coupling.
Solution Approach 2:
The nested arrangement of the secondary spring accumulator inside the barrel creates a compact structure that reduces overall device complexity. The direct engagement between the inner circumference of the barrel and outer circumference of the secondary spring accumulator eliminates the need for complex transmission gears and shafts.
3Power
If intermediate components are used in the transmission path, then power transfer is achieved, but installation space increases
Solution Approach 1:
The invention places the secondary spring accumulator inside the barrel, with the secondary spring accumulator's outer circumference directly engaging the inner circumference of the barrel. This nested configuration eliminates intermediate transmission components and significantly reduces the volume required for the power transfer mechanism.
Solution Approach 2:
By removing the third wheel, third wheel shaft, and associated intermediate components from the transmission path, the invention reduces the installation space required for the power transfer mechanism while maintaining effective power transfer from the primary to secondary spring accumulator.
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 design ensures a high torque is effectively applied to the cam disk with minimal effort, enhancing the reliability and accuracy of the switching unit while reducing power loss and installation space, leading to a compact and efficient watch mechanism.
Implementation Method 1
the secondary spring accumulator is a spiral spring which coaxially encloses the seconds arbor and is fastened with its radially inner end to the seconds arbor and with its radially outer end to the holding plate
Implementation Method 2
an air vortex brake can be driven in a simple, wear-free manner by the drive train leading to the stop wheel, which air vortex brake can have a rotatably drivable brake axle that has radially directed brake vanes
Data Source
Figure 1
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AI summary
The watch has a constant force device for admission of oscillating systems. A switch gear unit (9) of the constant force device is provided for periodically controlling clamp of a secondary spring brake of clamping modules of the constant force device by a primary spring brake forming a barrel. The periodic controlling of the switch gear unit takes place by a cam plate (16), which is permanently and rotatably driven. A secondary shaft (18) is rotatably driven by the secondary spring brake. The shaft carries the cam plate and the secondary wheel driving the oscillating system.