Watch Case Back Angular Positioning via Indexing Elements
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Solution Overview
Problem
Watch cases with fixed back orientations are difficult to manufacture and maintain due to the lack of control over the angular position of the back relative to the middle, which affects aesthetics and quality, especially when decorative elements are involved, and existing solutions are complex and costly.
Innovation Solution
A watch case design featuring a middle with a threaded ring that cooperates with the back to immobilize it in a single predefined angular position using indexing elements, allowing precise orientation and controlled tightening torque, simplifying production and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the back is attached to the middle by screwing with threads, then the back can be securely fixed to the middle, but the orientation of the back cannot be controlled relative to the middle
Solution Approach 1:
The solution divides the attachment function into two separate mechanisms: the threaded ring provides secure fixation through screwing, while the indexing elements (protrusion and recess) provide angular position control. This segmentation allows each mechanism to perform its specific function effectively without interfering with the other.
Solution Approach 2:
The indexing elements act as intermediary features between the back and the middle. The protrusion on the back engages with the recess in the middle to define the angular position, serving as a mediator that enables precise orientation while the threaded ring handles the secure fixation.
2Manufacturing precision
If specific machining of internal and external threads is carried out to control angular position, then the back can be positioned in a known angular position, but the manufacturing process becomes difficult and expensive
Solution Approach 1:
The indexing elements utilize asymmetric geometric features (a protrusion and a corresponding recess) that are simple to machine but effectively control angular position. These asymmetric features are much easier to manufacture than precisely machined threaded interfaces with angular control, reducing both complexity and cost.
Solution Approach 2:
The indexing elements are simple, inexpensive geometric features that can be easily added to the back and middle components during standard manufacturing processes. They provide precise angular control without requiring expensive specialized machining operations.
3Ease of manufacture
If the back is attached without angular position control, then the manufacturing process is simple, but the aesthetics and perceived quality are prejudiced when the back has decorative elements or inscriptions
Solution Approach 1:
The attachment system is segmented into two independent functions: the threaded ring handles secure fixation with simple screwing operations, while the indexing elements (protrusion and recess) provide angular position control for aesthetic elements. This segmentation maintains manufacturing simplicity while achieving precise angular positioning.
Solution Approach 2:
The indexing elements automatically guide the back into the correct angular position during assembly. The protrusion fits into the recess, self-aligning the back relative to the middle without requiring complex adjustment procedures or specialized machining operations.
4Manufacturing precision
If a lost or damaged back must be replaced with angular position control through specific thread machining, then the angular position is maintained, but after-sales service becomes difficult
Solution Approach 1:
The replacement process is simplified by segmenting the attachment functions: the threaded ring allows easy removal and reattachment for replacement, while the indexing elements (protrusion and recess) ensure automatic angular position alignment. This segmentation makes after-sales service easier compared to complex threaded angular control.
Solution Approach 2:
The indexing elements provide self-aligning functionality during back replacement. The protrusion fits into the recess, automatically guiding the back into the correct angular position without requiring skilled adjustment or specialized tools, making after-sales service straightforward.
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 ensures the back is securely fixed in a single angular position, enhancing aesthetics and quality while reducing manufacturing costs and simplifying assembly and after-sales service by preventing rotational mobility and allowing precise orientation.
Implementation Method 1
the back is held such that it bears against an annular bearing surface of the middle by a threaded ring cooperating, by screwing, with said middle
Implementation Method 2
the back comprising a single first indexing element configured to cooperate with a single second indexing element with which the middle is provided so as to immobilise said back such that it cannot rotate relative to the middle in a single, predefined angular position
Data Source
AI summary
A watch case includes a middle having a first opening receiving a crystal, opposite a second opening receiving a back. The back is held such that it bears against an annular bearing surface of the middle by a threaded ring cooperating, by screwing, with the middle. The back includes a first indexing element to cooperate with a second indexing element with which the middle is provided so as to immobilise the back in a single angular position such that it cannot rotate relative to the middle.