Fastenerless Polymer Chassis with Wire Mesh Shielding
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Solution Overview
Problem
The use of threaded fasteners in assembling electrical devices, such as automotive radios, is inefficient and prone to errors, leading to increased assembly time, risk of damage, and additional production steps, while also requiring complex fixtures and extra inventory, which complicates high-volume production and can result in electrical failures due to metal shavings.
Innovation Solution
A screwless assembly method using a polymer-based chassis with integrated wire mesh for electromagnetic shielding and structural support, allowing components to be snap-locked into place without the need for fasteners or specialized tools, thereby simplifying the assembly process and reducing handling and inventory requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If threaded fasteners are used to assemble subassemblies to the chassis, then the subassemblies are securely retained and properly located, but the assembly cycle time becomes very long and labor costs increase
Solution Approach 1:
The patent removes threaded fasteners from the assembly process entirely, extracting the problematic component that caused long assembly times. Instead, it uses a chassis with integrated locating features and retention mechanisms that secure subassemblies without requiring separate fastening operations, thus maintaining reliability while dramatically improving productivity.
Solution Approach 2:
The patent combines the functions of locating, supporting, and retaining subassemblies into the chassis structure itself. The chassis integrates locating features, support surfaces, and retention mechanisms into a unified structure, eliminating the need for separate fasteners and reducing assembly steps while maintaining secure retention.
2Reliability
If threaded fasteners are used, then subassemblies are securely attached, but the risk of damage to electrical components increases due to fastener installation errors
Solution Approach 1:
The patent employs self-aligning and self-retaining features where the chassis structure automatically guides and secures subassemblies without requiring manual fastener installation. The self-service mechanism eliminates human error in fastener application, preventing damage to electrical components while maintaining secure attachment.
Solution Approach 2:
The patent incorporates protective features into the chassis design that cushion and protect electrical components during the assembly process. The structure includes protective barriers and controlled engagement features that prevent accidental damage before components are fully secured, addressing potential harm in advance.
3Productivity
If self-tapping fasteners are used to reduce assembly steps, then fewer production steps are required, but metal shavings are generated that can cause electrical failures
Solution Approach 1:
The patent removes self-tapping fasteners from the assembly process, extracting the source of metal shavings. Instead, it uses a fastener-free attachment system where subassemblies are secured through integrated chassis features, eliminating the harmful byproduct while maintaining assembly efficiency.
Solution Approach 2:
The patent replaces permanent metal fasteners with disposable or reusable plastic retention features integrated into the chassis. These features are designed to be used once and then discarded or reused without generating harmful shavings, maintaining productivity while eliminating contamination risks.
4Reliability
If threaded fasteners are used, then subassemblies are securely mounted, but additional inventory burden and special tools are required
Solution Approach 1:
The patent designs the chassis with universal locating and retention features that can accommodate multiple types of subassemblies without requiring different fasteners or specialized tools. The multi-functional chassis structure maintains secure mounting while reducing inventory complexity by eliminating the need for various fastener types and associated tooling.
Data Source
AI summary
A lightweight radio/CD player for vehicular application is virtually “fastenerless” and includes a case and frontal interface formed of polymer based material that is molded to provide details to accept audio devices such as playback mechanisms (if desired) and radio receivers, as well as the circuit boards required for electrical control and display. The case and frontal interface are of composite structure, including an insert molded electrically conductive wire mesh screen that has been pre-formed to contour with the molding operation. The wire mesh provides EMC, RFI, BCI and ESD shielding and grounding of the circuit boards via exposed wire mesh pads and adjacent ground clips. The major components and subassemblies self-interconnect by integral guide and connection features effecting “slide lock” and “snap lock” self-interconnection. The major components and subassemblies self-ground by establishing an interference fit with exposed, resilient, embossed portions of wire mesh.