Slot Closure Device With Mechanical Spring Activation

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Solution Overview

Problem

Existing slot closure arrangements for electrical machines face challenges such as small spring deflections, complex manufacturing, adhesive residue issues, uncertainty in heat-activatable adhesive connections, and the risk of screw residues remaining in the machine, leading to unreliable clamping and potential damage.

Innovation Solution

A preassembled slot closure arrangement with a spring element between a sliding block and a pressure piece, where the fastening means is mechanically transferred from a first to a controllable second position to activate spring forces without energy input, allowing for visual inspection and reduced risk of residue, using non-metallic fasteners and wedge designs for enhanced reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heat-activatable adhesive connections are used to secure the spring element, then the spring forces can be activated after insertion, but there is uncertainty whether and how much the adhesive connection has actually broken

Engineering Contradiction:
Improvereliability of spring force activationVSAvoiddetectability of adhesive connection status
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent employs visual indicators such as color changes or visible markings on the adhesive connection or surrounding components to indicate whether the adhesive has been properly broken and spring forces activated. This allows operators to visually confirm the activation status without disassembly or complex measurement tools.

Inventive Principle:
Principle #32Color changes

2Reliability

If thermoactive or thermoactivatable screws are used to prestress the spring element, then the prestressing effect can be eliminated after heating, but there is the problem of broken off screw residues remaining uncontrollably in the electrical machine

Engineering Contradiction:
Improvereliability of prestress eliminationVSAvoidharmful effect of screw residues
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs disposable or sacrificial fastening elements that are designed to be removed or degraded after use. These elements are intentionally left outside the machine or designed to fall out controllably, eliminating the risk of residues remaining inside the electrical machine while still providing the necessary prestressing function during assembly.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent extracts the fastening function from permanent components and uses temporary fastening elements that are removed after serving their purpose. This separation ensures that no residues remain in the machine while the prestressing effect is properly eliminated after heating.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the slot closure arrangement is inserted with the spring element in the prestressed state, then the winding can be held reliably, but the available spring deflections are relatively small

Engineering Contradiction:
Improvereliability of winding retentionVSAvoidspring deflection range
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent applies preliminary prestressing to the spring element during assembly to ensure immediate and reliable winding retention. The spring element is pre-compressed or pre-tensioned before insertion, allowing it to engage the winding securely from the start while maintaining sufficient deflection capacity for operational requirements.

Inventive Principle:
Principle #10Preliminary action

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 solution enables efficient, reliable, and visually inspectable slot sealing with reduced risk of residue, improving assembly economy and operational safety by activating spring forces mechanically and ensuring secure winding retention without heat or additional tools.

Implementation Method 1

a spring element (4), arranged between a sliding block (2) and a pressure piece (3), which can be brought into an activatable, prestressed state

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

at least one wedge design for enhanced reliability

Methodology Applied
Scientific EffectWedge: Wedge

Data Source

PatentEP2187504B1Slot closing device
Publication Date: 2018.10.03 ABB (SCHWEIZ) AG
  • EP2187504B1 patent drawingFigure 1~2
  • EP2187504B1 patent drawingFigure 3~5

AI summary

The slot closure arrangement (1) has a spring element (4) that is arranged between a sliding block (2) and a pressure plate (3). The attachment is mechanically moved from a position to another position, which is monitored, after positioning of the slot closure arrangement, for activation of the spring forces of the spring element. An independent claim is included for a slot closure method.