Two-Shot Injection Molded Housing Keycap Orientation
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Solution Overview
Problem
In devices with limited real estate for keycaps, such as remote controls and keyboards, achieving an aesthetically pleasing piano key arrangement with accurate positioning and spacing is challenging due to the need for precise sizing and mounting, which can affect both aesthetics and functionality.
Innovation Solution
A user-interface design featuring a top part made from a combination of harder plastic and softer rubber elements, integrated through a two-shot injection molding process, with complementary profiles and snap-fit mechanisms to ensure accurate keycap orientation and secure attachment, reducing material waste and assembly costs while enhancing robustness and liquid resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If accurate positioning and mounting of keycaps is implemented to achieve piano key arrangement, then aesthetic appearance and spatial utilization are improved, but manufacturing complexity and assembly precision requirements increase
Solution Approach 1:
The top part is pre-formed with integrated pins and complementary profiles during the two-shot injection molding process, establishing precise keycap positions before assembly. This preliminary structuring eliminates the need for complex post-assembly positioning adjustments.
Solution Approach 2:
The pin acts as an intermediary element between the top part and keycap, providing a simple mechanical interface that ensures accurate positioning. The complementary profile on the keycap bottom face engages with the pin, automatically orienting and locating the keycap without requiring complex mounting fixtures.
2Reliability
If conventional single-material housing is used, then manufacturing process is simple, but liquid resistance and structural functionality are insufficient
Solution Approach 1:
The housing top part uses a composite structure with a harder plastic element providing structural support and a softer rubber layer providing liquid resistance and cushioning. This multi-material approach enhances both reliability against liquid spills and structural functionality while maintaining manufacturing feasibility through two-shot injection molding.
3Reliability
If keycaps are securely attached to prevent dislocation, then operational reliability is improved, but assembly complexity increases
Solution Approach 1:
The snap-fit mechanism between the protruding sleeve on the keycap and the pin provides self-aligning and self-securing functionality. When the keycap is placed on the pin, the complementary profiles automatically engage, orienting and securing the keycap without requiring external fixtures or complex assembly operations.
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 design allows for precise control of keycap spacing and height differences, improving aesthetics and functionality while reducing production costs and enhancing the device's ability to withstand spills, with adjustable force requirements through the elasticity of the rubber and rib deformation.
Implementation Method 1
The softer rubber layer serves as the seats for the keycaps... The softer rubber layer acts as a cushion and clamps the keycaps to prevent dislocation and accidental removal
Implementation Method 2
The top part is made in a two-shot injection molding process. The harder plastic element has one or more openings occupied by the softer rubber layer
Implementation Method 3
The specific keycap has a bottom face with a specific protruding sleeve configured for engaging with the specific pin, e.g., through a snap-fit
Data Source
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AI summary
A device has a housing with a top part that accommodates one or more pressable keys forming the user-interface of the device. Each specific key has a specific keycap. The top part is formed from a harder plastic element and a softer rubber layer in a two-shot injection molding process. The harder plastic element has one or more openings occupied by the softer rubber layer. The harder plastic element has a specific pin positioned in a specific hole of the softer rubber layer. The specific keycap has a bottom face with a specific protruding sleeve configured for engaging with the specific pin. The bottom face of the specific key and an area at a top face of the softer rubber layer have complimentarily shaped profiles configured for accurately orienting the keycap relative to the top part.