Oblique Guide Hole Casing Assembly Without Screws
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Solution Overview
Problem
Existing device casing configurations require screw holes for fastening, which complicate assembly and increase dimensions, and existing assembly methods are difficult due to deformations from resin molding processes.
Innovation Solution
A casing design featuring a first casing member with guide and fitting holes and a second casing member with protrusions that fit into these holes, allowing for oblique guidance and secure fitting without screws, facilitating easier assembly and reducing external dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If screw holes are formed for fastening the cover member to the casing main body, then the cover member can be securely fixed, but the external dimensions of the casing increase and the assembly becomes more complex
Solution Approach 1:
The hole is segmented into two functional parts: a guide hole portion for alignment and insertion, and a fitting hole portion for secure fixation. This segmentation allows the protrusion to be guided into position and then firmly engaged, achieving secure fixing without requiring additional screw holes that would increase external dimensions
Solution Approach 2:
The single hole structure serves multiple functions: it acts as a guide for alignment, a pathway for insertion, and a fitting mechanism for secure fixation. This multi-functionality replaces what would traditionally require separate guide holes, clearance holes, and screw holes, thereby reducing overall casing dimensions while maintaining fixing strength
2Strength
If screw holes are formed around the accommodating space, then the cover member can be fastened securely, but the device complexity increases due to multiple fastening points
Solution Approach 1:
The guide function and fitting function are merged into a single hole structure. The guide hole portion and fitting hole portion work together as an integrated feature, eliminating the need for separate guide holes and fastening holes. This merging reduces the number of components and assembly steps while maintaining secure fixation
Solution Approach 2:
The fastening function is extracted from the traditional screw-based system and integrated into the hole-protrusion fitting mechanism. This extraction eliminates the need for separate fasteners (screws, bolts) and reduces assembly complexity by incorporating the fixing mechanism directly into the casing structure
3Ease of manufacture
If protrusions are made to fit into grooves laterally, then the cover member can be fixed without screws, but assembly becomes difficult due to resin deformation
Solution Approach 1:
The fitting direction is changed from purely lateral to oblique. The guide hole is inclined relative to the lateral direction, allowing the protrusion to be inserted at an angle. This dimensional change in the insertion path accommodates resin deformation and warpage, making assembly easier while still achieving secure fixation without screws
Data Source
AI summary
A device casing is configured to include a first casing member provided with a hole including a guide hole and a fitting hole that communicates with the guide hole, and a second casing member provided with a protrusion at a position corresponding to the hole, the second casing member being configured to be fixed with respect to the first casing member by fitting the protrusion to the fitting hole. The guide hole guides movement of the protrusion that entered within the guide hole in an oblique direction when fixing the second casing member with respect to the first casing member so that the second casing member can get close to the first casing member in a state where the second casing member is guided in the oblique direction. The protrusion that moved in the oblique direction along the guide hole, passed through the guide hole and reached inside the fitting hole fits to the fitting hole. The second casing member is fixed with respect to the first casing member by the fitting of the protrusion to the fitting hole.