Inner Frame with Spread Portions for Secure Case Fit
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Solution Overview
Problem
Conventional inner frames in electronic devices, such as wristwatches, face issues with being scraped off when made of plastic and housed within metal case members due to friction, leading to shavings that can cause problems, and setting the diameter equal to the case member's inner periphery results in rattling and increased manufacturing costs.
Innovation Solution
An inner frame with a side wall portion having a smaller outer diameter than the case member's inner periphery, featuring cut-out portions and spread portions that are pushed outward by the module member to securely fit within the case member, preventing scraping and rattling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the inner frame is made of plastic and press-fitted into a metal case member to increase close fit, then the close fit between inner frame and case member is improved, but the inner frame surface is scraped off by friction generating shavings
Solution Approach 1:
The patent changes the diameter parameter of the inner frame, setting it smaller than the inner periphery diameter of the case member. This parameter change creates clearance that prevents direct contact and friction between the inner frame outer surface and case member inner surface, thereby eliminating shavings while maintaining secure positioning through the spread portion mechanism
2Stability of the object's composition
If the inner frame outer diameter is set equal to the case member inner periphery diameter to prevent rattling, then the positioning stability is improved, but the inner frame is scraped off and shavings are produced
Solution Approach 1:
The patent applies local quality by creating a non-uniform fit between the inner frame and case member. The spread portions provide local contact points for stable positioning, while the clearance areas prevent friction and shavings. This localized differentiation allows simultaneous achievement of stability and prevention of harmful friction
Solution Approach 2:
The spread portions act as intermediaries between the inner frame and case member. These portions are pushed outward to contact the case member inner surface, providing stable positioning without requiring the entire inner frame outer surface to contact the case member, thereby preventing widespread friction and shavings
3Object-generated harmful factors
If the inner frame outer diameter is set smaller than the case member inner periphery diameter to prevent scraping, then shavings are prevented, but the inner frame and module member may move and rattle
Solution Approach 1:
The patent introduces dynamics by making the spread portions deformable. During assembly, the spread portions are pushed outward by the module member to contact the case member inner surface, dynamically adapting to secure the inner frame in position and prevent rattling, while maintaining clearance to prevent friction and shavings
4Stability of the object's composition
If additional spacers are added to secure the inner frame when diameter is reduced, then positioning stability is improved, but the number of parts and manufacturing cost increase
Solution Approach 1:
The patent merges the functions of the inner frame and securing mechanism into a single integrated component. The inner frame itself includes the spread portions that act as securing elements, eliminating the need for separate spacers or additional securing parts. This integration maintains positioning stability while reducing part count and 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
The solution prevents the inner frame from being scraped off during assembly, ensures secure positioning of the module member within the case member without rattling, and reduces manufacturing costs by simplifying the structure and eliminating the need for additional spacers.
Implementation Method 1
at least one part of the side wall portion is configured as a spread portion which is spread by the module member so as to fit an outside surface thereof on the inner peripheral surface of the case member
Data Source
AI summary
An inner frame includes a side wall being set its outer diameter to be smaller than a diameter of an inner periphery of a case and arranged along an inner peripheral surface of the case when the frame is housed within the case. The wall is divided into spread portions by cut outs, each cut out in a thickness direction of the case, and the spread portions are spread to make an outside surface thereof fit on the inner peripheral surface of the case when the module is press-fitted from an opening of the case. An inside surface of each spread portion is provided with a projection to be brought into contact with an outside surface of the module and to push and spread outward the spread portion when the module is press-fitted into the frame. A case unit includes the module, the case, and the frame.