Barrel Spring Torque Consistency via Segmented Elastic Design
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Solution Overview
Problem
Current barrel springs provide a non-constant torque throughout their unwinding, affecting the precision of timepiece movements and are challenging to manufacture due to size limitations and production costs associated with S-shaped springs.
Innovation Solution
A barrel design incorporating additional elastic energy accumulating means, such as elastic protuberances, integrated with the spiral spring to enhance torque and allow for personalized torque based on winding tension, enabling more compact and mass-producible asymmetrical springs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If S-shaped springs are used in current barrels, then the spring can store mechanical energy, but the torque varies throughout the unwinding process affecting precision
Solution Approach 1:
The spring is divided into multiple active segments or zones with different stiffness characteristics. Each segment contributes differently to the torque output, allowing the overall torque to be more consistent throughout the unwinding process. This segmentation enables precise control over the torque profile by adjusting the properties of individual segments.
Solution Approach 2:
Different portions of the spring are given different local properties, such as varying thickness, width, or material composition. This allows specific regions of the spring to provide different stiffness values, enabling the spring to compensate for torque variations in different parts of its rotation range and achieve more consistent overall torque.
2Ease of manufacture
If S-shaped springs are used, then the spring can function in the barrel, but the spring shape is difficult to reconcile with positive or negative fabrication methods
Solution Approach 1:
The spring design embraces asymmetry in a controlled manner, using asymmetric geometries that are actually easier to manufacture with photolithography and electroforming than symmetric S-shapes. The asymmetric design allows for optimized stress distribution and easier integration with the barrel components while being compatible with standard fabrication processes.
Solution Approach 2:
The spring design transitions from a two-dimensional S-shape to a three-dimensional structure that better accommodates the constraints of photolithographic fabrication. This may include varying thickness profiles, multi-layer constructions, or vertical elements that are easier to create with additive or electroforming processes while maintaining the required mechanical functionality.
3Productivity
If substrates are used for spring fabrication, then springs can be manufactured, but the substrate size is not large enough and insufficient number of springs are made on a single substrate
Solution Approach 1:
The spring design is segmented into multiple identical or similar units that can be arranged in arrays on a single substrate. This allows many springs to be fabricated simultaneously on one substrate, dramatically increasing productivity. The segmented design also enables modular assembly and reduces the required substrate area per spring.
Solution Approach 2:
The spring design incorporates universal features that allow the same substrate to serve multiple functions: supporting multiple springs, providing structural reinforcement, and potentially serving as part of the barrel housing. This multi-functionality maximizes the utilization of substrate area and reduces the total substrate size needed.
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 maintains or increases torque consistency, improves isochronism, and reduces production costs by allowing for mass production of compact springs with adjustable torque, suitable for both positive and negative fabrication methods.
Implementation Method 1
an additional elastic means of accumulating energy provided in addition to the spiral shape of said at least one spring
Data Source
AI summary
The invention relates to a barrel. According to the invention, the barrel further includes a device for increasing the torque of said at least one spring including additional elastic energy accumulating means provided in addition to the spiral shape of said at least one spring, said elastic means being added to said at least one spring so that the barrel torque is personalized according to the winding tension of said at least one spring.