Watch Caseback With Asymmetric Bearing Surfaces for Precise Orientation
Solution Overview
Problem
Existing watch case assemblies suffer from variable quality due to manual orientation of the caseback, which affects the alignment of patterns and compromises water and air tightness, requiring improved control over the orientation of the back in relation to the caseband.
Innovation Solution
A watch case design featuring complementary, non-circular axial annular bearing surfaces on the caseband and caseback, with specific radii and alternating arcs, ensures precise alignment and assembly, utilizing a radial gasket for consistent water and air tightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual pre-positioning of the back in relation to the caseband is used, then the assembly process is simple, but the precision of orientation of the backband is low and quality varies significantly
Solution Approach 1:
The patent applies asymmetry by designing non-circular bearing surfaces with specific geometric profiles (first arc with radius R1, second arc with radius R2 where R1 ≠ R2) on both the caseband and back. This asymmetric geometry creates a unique orientation position that can only be achieved in one specific angular position, thereby eliminating manual alignment errors and ensuring precise orientation without requiring complex alignment tools or procedures.
Solution Approach 2:
The patent utilizes curvature by designing the bearing surfaces with composite arc profiles consisting of two different radius arcs. This curved geometric design allows for smooth engagement and precise positioning through the interaction of the complementary profiles, enabling automatic alignment when the back is driven into the caseband without requiring manual intervention.
2Reliability
If visual markers or notches are used for orientation adjustment, then the assembly process remains manual, but the quality level and consistency of assemblies produced vary significantly
Solution Approach 1:
The patent implements self-service by designing the bearing surfaces with complementary non-circular profiles that automatically guide the back into the correct orientation position during the driving process. The asymmetric geometry creates mechanical constraints that force the components into the precise angular relationship without requiring manual adjustment, visual markers, or operator skill, thereby ensuring consistent assembly quality and eliminating variability.
3Manufacturing precision
If the back is driven into the caseband without precise orientation control, then the assembly process is fast, but water and air tightness and mechanical strength are compromised
Solution Approach 1:
The patent applies preliminary action by pre-configuring the bearing surfaces with complementary asymmetric profiles before assembly. This pre-designed geometric relationship ensures that when the back is driven into the caseband, the components automatically align to the precise orientation position during the driving process itself, without requiring separate alignment steps. This maintains assembly speed while ensuring precise orientation control and compromised-free sealing.
Data Source
Figure 1~3
AI summary
The invention relates to a watch case (10) comprising a case back (30) pressed into a case middle (20) by means of a gasket (40), the case back (30) comprising a body (31) from which a lip (32) extends radially, said body (31) comprising an axial annular bearing surface (310) and said lip (32) comprising a radial annular bearing surface (320), the case middle (20) comprising an axial opening (21) and having an axial annular bearing surface (200) extending opposite the axial annular bearing surface (310) of the case back body (31), and a radial annular bearing surface (201) bearing against the radial annular bearing surface (320) of the lip (32), the gasket (40) being interposed between the axial annular bearing surfaces (200, 310) of the case middle (20) and the bottom (30), the axial annular spans (200, 310) of the case (20) and of the bottom (30) having peripheral profiles of complementary shapes, substantially circular, comprising both,a first portion in the shape of an arc of a circle having a first radius (R1, R2), and a second portion in the shape of an arc of a circle to which the first portion is connected, having a second radius (r1, r2) whose value is smaller than that of the first radius (R1, R2).