Undercut Retaining Device for Metal Plate Fastening

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Solution Overview

Problem

Conventional fastening methods for functional supports on metal plates in mobile communications technology often compromise impermeability and lead to intermodulation issues, which are detrimental in high-frequency technology.

Innovation Solution

A retaining and anchoring device is created on a metal plate with a hole-free design, utilizing a sheet stamping with an undercut to securely fasten functional supports without the need for additional parts like screws or nuts, ensuring impermeability and preventing accidental removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fastening methods (screws, nuts, rivets) are used to fasten functional supports on metal plates, then the fastening strength and reliability are improved, but the impermeability of the metal sheet is compromised and intermodulation issues occur

Engineering Contradiction:

Improvefastening reliabilityVSAvoidimpermeability loss and intermodulation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention merges the fastening function and sealing function into a single integrated retaining device made of electrically conductive material. The retaining device combines mechanical anchoring (through the undercut geometry) with electrical continuity (through conductive material), eliminating the need for separate seals or gaskets while maintaining both fastening reliability and impermeability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention changes the material parameter from conventional non-conductive plastics to electrically conductive material. This parameter change enables the retaining device to provide both mechanical fastening and electrical continuity, preventing intermodulation by maintaining the electromagnetic shielding properties of the metal sheet

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If holes are made in the metal sheet to introduce screw shafts for fastening, then the fastening capability is improved, but the impermeability and electrical continuity of the metal sheet are compromised

Engineering Contradiction:

Improvefastening capabilityVSAvoidimpermeability loss

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention creates the retaining device with an integrated undercut geometry before installation. The undercut is pre-formed in the metal sheet through stamping or punching, creating a mechanical lock that prevents removal of the functional support. This preliminary action eliminates the need for separate fastening components and maintains sheet integrity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention extracts the fastening function from the metal sheet material itself by creating an integrated undercut retention geometry. Instead of adding external fasteners, the fastening capability is taken out and embedded directly into the sheet structure through the retaining device, maintaining impermeability while enabling secure attachment

Inventive Principle:

Principle #2Taking out (Extraction)

3Strength

If additional fastening parts (screws, nuts, sealing elements) are used, then the fastening strength is improved, but the device complexity and number of components increase

Engineering Contradiction:

Improvefastening strengthVSAvoidnumber of components

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The invention merges multiple functions (fastening, sealing, electrical continuity, and retention) into a single retaining device component. This consolidation maintains fastening strength through the undercut geometry while eliminating the need for separate nuts, seals, and gaskets, thereby reducing device complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The retaining device is designed with multi-functionality, serving as both a mechanical fastener and an electrical conductor while providing retention through the undercut geometry. This universal component replaces multiple specialized parts, reducing overall device complexity while maintaining or improving fastening strength

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS9912035B2Retaining and anchoring device on a metal plate for fastening a functional support

Publication Date: 2018.03.06 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A retaining and anchoring device forming a retaining and anchoring section on a metal plate on a reflector includes a recess provided in the metal plate. The recess has on an upper face of the metal plate a peripheral edge or edge sections spaced apart from one another. An undercut or several undercut sections are formed below the peripheral edge or the edge sections. The recess is free of bores or passages. A locking device prevents unintentional removal of a snap-on mechanism from the recess beyond an edge section or plural edge sections which cover the undercut section(s).