Thermoplastic Switch Housing Vibration Welding for Sealed Assembly

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Solution Overview

Problem

Traditional methods for manufacturing medium-voltage load-break switches are labor-intensive and time-consuming, requiring skilled personnel and high costs due to the need for precise assembly and sealing of housing shells.

Innovation Solution

A method using thermoplastic housing shells with ribs of varying thicknesses and heights, assembled and joined via vibration welding to form a sealed outer casing without mechanical fasteners or sealing gaskets, allowing for faster and easier assembly by inexperienced personnel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional manual assembly methods with mechanical fasteners and sealing gaskets are used, then reliable sealing and mechanical connection are achieved, but manufacturing time and labor costs increase significantly

Engineering Contradiction:
Improvesealing reliabilityVSAvoidmanufacturing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces mechanical fastening systems (screws, clips) and sealing gaskets with a vibration welding process that creates permanent molecular-level bonds between thermoplastic housing shells. The vibration welding apparatus applies ultrasonic vibrations to melt and fuse the plastic materials directly, eliminating the need for separate mechanical fasteners and sealing components, thereby dramatically reducing assembly time while maintaining reliable connections

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the temperature and viscosity parameters of thermoplastic materials during vibration welding. By controlling the vibration amplitude, frequency, and duration, the plastic material at the coupling edges is heated to a molten state, allowing it to flow and intermix between mating surfaces. Upon cooling, the material solidifies to form a strong, sealed joint, effectively changing the physical state of the material to achieve both mechanical strength and sealing

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional manual assembly with precise surface finishing is used, then optimal sealing is achieved, but the process requires expert personnel and increases manufacturing complexity

Engineering Contradiction:
Improvesealing qualityVSAvoidassembly difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The vibration welding process is self-aligning and self-regulating. The ultrasonic vibration automatically distributes the molten plastic material evenly across the coupling surfaces, and the process parameters (vibration amplitude, pressure, time) self-adjust to compensate for minor variations in surface flatness or rib positioning. This eliminates the need for expert manual intervention and precise pre-finishing, allowing inexperienced operators to achieve consistent sealing quality

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The housing shells are pre-formed with integrated coupling edges and ribs during molding, incorporating the sealing features directly into the plastic parts themselves. This preliminary integration of sealing structures eliminates the need for separate sealing components and reduces assembly steps, making the manufacturing process simpler while maintaining sealing effectiveness

Inventive Principle:
Principle #10Preliminary action

3Strength

If multiple mechanical fasteners are used to couple housing shells, then secure mechanical connection is achieved, but assembly time and labor requirements increase

Engineering Contradiction:
Improvemechanical connection strengthVSAvoidassembly time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent merges the functions of mechanical fastening and sealing into a single vibration welding operation. The ultrasonic vibration process simultaneously creates the mechanical bond and the sealed joint in one continuous action, eliminating the need for multiple separate fasteners and sealing components. This consolidation reduces the number of assembly steps from multiple fastener installations to a single welding process, dramatically reducing assembly time while maintaining connection strength

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing shells are made of thermoplastic materials that exhibit both structural strength and weldability. The composite structure includes reinforced coupling edges with ribs that provide both mechanical interlocking and sufficient material volume for vibration welding, achieving strong mechanical connections through the inherent properties of the thermoplastic material rather than through separate fastening components

Inventive Principle:
Principle #40Composite materials

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

This approach significantly reduces manufacturing time and costs, enabling industrial-scale production of sealed switching apparatuses with improved mechanical connection and sealing, suitable for medium-voltage applications.

Implementation Method 1

joining the first and second coupling edges of said first and second housing shells through a vibration welding process, thereby forming a junction between said first and second housing shells

Methodology Applied
Scientific EffectVibration welding: Friction Welding

Implementation Method 2

During said vibration welding process, the first and second coupling edges of said first and second housing shells are moved back and forth, relative to each other, along a main vibration direction

Methodology Applied
Scientific EffectFriction heating: Friction

Data Source

PatentEP4117004B1Method for manufacturing a switching apparatus for electric systems
Publication Date: 2024.12.18 ABB (SCHWEIZ) AG
  • EP4117004B1 patent drawingFigure 1
  • EP4117004B1 patent drawingFigure 2
  • EP4117004B1 patent drawingFigure 3

AI summary

Method for manufacturing a switching apparatus for electric systems, comprising the following steps: - providing a first housing shell (3) of said switching apparatus, said first housing shell being of thermoplastic material and including a first coupling edge (4) for coupling with another housing shell, said first coupling edge having a first coupling surface and first ribs protruding from said first coupling surface and extending along said first coupling edge; - providing a second housing shell (5) of said switching apparatus, said second housing shell being of thermoplastic material and including a second coupling edge (6) for coupling with said first housing shell, said second coupling edge having a second coupling surface and second ribs protruding from said second coupling surface and extending along said second coupling edge; - assembling said first and second housing shells and a number of operating components of said switching apparatus, thereby obtaining a preliminary assembly (99) of said switching apparatus; - joining the first and second coupling edges of said first and second housing shells through a vibration welding process, thereby forming a junction between said first and second housing shells and obtaining a sealed outer casing for said switching apparatus.