Battery Charger Guide Portion Sloped Drainage Design
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Solution Overview
Problem
Existing battery chargers for electric tools face issues with water retention and dust accumulation on the guide portions due to their design, which can lead to complex structures and functionality problems when trying to form thin-walled resin portions without openings for drainage.
Innovation Solution
The battery charger incorporates a guide portion with an exposed step portion formed by reducing the thickness of the resin from the outside, featuring a sloped recessed portion that allows water and dust to drain away, and includes a drainage path at the lower end of the slope, which can be slit-like, integrated with the case, to prevent water and dust accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a mold is applied to the guide portion from the inner side toward the outer side to reduce wall thickness, then the guide portion can be formed as a thin-walled portion, but an opening communicating with the inner and outer sides must be formed which allows water to enter inside the case
Solution Approach 1:
The patent inverts the conventional molding approach by applying the mold from the outer side toward the inner side instead of from the inner side toward the outer side. This reversal allows the guide portion to be formed as a thin-walled structure while preventing the formation of communicating openings that would allow water to enter the case interior.
Solution Approach 2:
The patent converts the potential harm of water entry into a benefit by designing the guide portion with a sloped outer surface that directs water away from the case opening. The thin-walled structure, which initially seemed to create vulnerability, is transformed into an advantage by combining it with a water-repellent sloped surface.
2Object-affected harmful factors
If a mold is applied to the guide portion from the outer side toward the inner side to reduce wall thickness, then water entry is prevented, but the outer portion of the guide portion becomes concave which causes water retention and dust accumulation
Solution Approach 1:
The patent applies a sloped curved surface to the outer surface of the guide portion instead of a flat or concave surface. This curvature design allows water to flow smoothly off the surface due to gravity, preventing water retention and dust accumulation while maintaining the thin-walled structure formed by outer-side molding.
3Ease of manufacture
If the guide portion is formed as a thin-walled portion by applying mold from the inner side, then manufacturing is simplified, but a drainage path must be provided which complicates the internal structure
Solution Approach 1:
The patent extracts the drainage function from the internal case structure and relocates it to the outer surface of the guide portion. By forming the guide portion with a sloped outer surface that directs water away, the need for internal drainage paths is eliminated, simplifying both the molding process and the internal structure.
4Device complexity
If the guide portion is formed as a thin-walled portion by applying mold from the outer side, then water entry is prevented and structure is simplified, but the concave configuration causes water and dust to accumulate
Solution Approach 1:
The patent resolves the concave configuration issue by designing the outer surface of the guide portion with a sloped curvature that promotes water runoff. This curved surface design eliminates water and dust accumulation while maintaining the simplified structure achieved by outer-side molding.
Data Source
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AI summary
Female guide portions (20) for slidingly attaching a battery pack (B) are formed by integral molding of a case main body. Exposed step portions are formed on the female guide portions (20), which includes protruding portions (21) as thin-walled portions by application from the outer side (the upper side) of a mold so as to reduce the thickness of a thick-walled resin portion. An opening communicating with the inner and outer side of the case (11) is not provided, while the protruding portions (21) are formed as thin-walled portions. Bottom surfaces of the exposed step portions (22) are formed so as to be sloped with respect to the horizontal direction when the battery charger (10) is placed on a horizontal base, and water dropped on the bottom surfaces (23) can flow outside of the case (11) due to the slope without remaining thereon.