Brittle Material Assembly Element With Dual-Layer Elastic Clamping
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Solution Overview
Problem
Brittle materials like silicon, used in timepieces, face challenges in fixing assembly elements such as watch hands and toothed wheels due to lack of plastic deformation, making conventional fastening methods ineffective, and require improved clamping forces to withstand impacts and rotations.
Innovation Solution
The use of elastic structures in two layers of the assembly element, with different types of elastic structures in each layer, allows for enhanced clamping force distribution and control, optimizing resistance to linear and angular accelerations, and featuring angularly offset bearing surfaces to prevent material breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional driving fastening is used with brittle material, then the assembly element can be fixed on the shaft, but the material lacks plastic deformation capability causing fastening failure
Solution Approach 1:
The invention changes the physical state and mechanical properties of the assembly element by introducing elastic structures that can undergo reversible deformation. These elastic blades or fingers are designed with specific geometric parameters (length, thickness, curvature) that allow them to deform elastically during assembly and maintain constant clamping force, compensating for the lack of plastic deformation in brittle materials like silicon.
Solution Approach 2:
The invention creates a composite structure combining brittle material (silicon) with elastic elements (blades or fingers). The brittle material provides structural integrity while the elastic elements provide the necessary deformation capability for fastening. This composite approach allows the assembly element to exhibit both rigidity and flexibility, solving the contradiction between material strength and deformation capability.
2Reliability
If elastic structures are added to provide clamping force, then fastening reliability improves, but device complexity increases
Solution Approach 1:
The invention merges the fastening function directly into the assembly element body by integrating elastic blades or fingers as inherent structural features. Rather than adding separate fastening components, the elastic structures are formed as part of the assembly element itself, allowing it to perform both its primary function and fastening function simultaneously, thus improving reliability without proportionally increasing complexity.
Solution Approach 2:
The elastic structures are designed to automatically perform the fastening function through their inherent elastic properties. When the assembly element is installed, the elastic blades or fingers naturally deform and apply clamping force to the shaft, securing the assembly element without requiring additional fastening operations or components. This self-service mechanism simplifies the overall system while ensuring reliable fastening.
3Strength
If multiple elastic structures are used to distribute forces, then resistance to accelerations improves, but manufacturing complexity increases
Solution Approach 1:
The invention segments the elastic fastening system into multiple discrete blades or fingers distributed around the assembly element. This segmentation allows the clamping force to be distributed across multiple contact points, improving the element's resistance to linear and angular accelerations. The segmented structure also enables better force distribution and reduces stress concentration on any single elastic element.
Solution Approach 2:
The elastic structures serve multiple functions simultaneously: they provide clamping force for fastening, distribute mechanical loads during operation, absorb shock and vibration, and compensate for manufacturing tolerances. This multi-functionality allows a single structural feature to address multiple performance requirements, improving strength and acceleration resistance without proportionally increasing manufacturing complexity.
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 provides improved clamping force and control, ensuring secure attachment of assembly elements in timepieces while preventing material breakage, enabling effective operation under rotational and impact stresses.
Implementation Method 1
The inner wall of the opening comprises elastic structures which are engraved in the plate and which each comprise at least one bearing surface for radially clamping the shaft in order to ensure the fixing of the assembly element with respect to the shaft
Data Source
Figure 1~4
Figure 5~15
Figure 6
AI summary
The assembly element (18), made of a brittle material plate, has an opening (32) for the axial insertion of a shaft (26). The inner wall (33) of the opening (32) has elastic structures (34) engraved in the plate, each of which has at least one bearing surface (36) for radially clamping the shaft (26) to secure the assembly element (18) to the shaft (26). The assembly element (18) has a first series (S1) of elastic structures (34) engraved in an upper layer (39) of the plate and a second series (S2) of elastic structures (34) engraved in a lower layer (41) of the plate. A watch component can be fitted with this assembly element.