Capacitor Discharge Welding for Ring Lock Assembly

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Solution Overview

Problem

Traditional spot welding techniques for manufacturing ring locks result in excessive heat generation, damage to parts, and increased production time and costs, while also allowing for potential breaking by applying tools between welds due to local connections, and the use of circumferential flanges limits assembly possibilities.

Innovation Solution

Capacitor discharge welding is employed to create continuous connections along the entire circumferential contour without circumferential flanges, using line contacts and facing plate end edges to minimize heat generation and provide a robust, sabotage-resistant connection, allowing for direct connection of end edges and reducing production time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If spot welding is used to connect front and rear lock caps, then welding operation can be performed, but substantial heat generation damages parts and protective coating

Engineering Contradiction:
Improvewelding operationVSAvoidheat generation damage
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the welding parameters by using capacitor discharge welding instead of conventional spot welding. This involves using a capacitor bank to store and release electrical energy in a controlled discharge, creating a localized plasma channel that melts and fuses the metal with minimal heat affect zone, thereby avoiding damage to protective coatings and surrounding parts.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional resistive heating mechanism of spot welding with an electrical discharge mechanism. By using capacitor discharge welding, the energy is delivered through a rapid electrical discharge that creates a controlled molten pool, substituting the gradual thermal buildup of traditional welding with a more precise energy delivery method.

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

2Ease of manufacture

If spot welding is used with spaced apart spots, then welding operation is simplified, but the lock can be broken by applying tools between spot welds

Engineering Contradiction:
Improvewelding operation simplicityVSAvoidresistance to breaking
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent implements continuous circumferential weld seams that form unbroken loops around the lock structure. This continuous welding eliminates gaps between discrete weld spots, creating a seamless connection that prevents insertion of breaking tools and provides uniform structural integrity around the entire circumference of the lock assembly.

Inventive Principle:
Principle #20Continuity of useful action

3Strength

If multiple welding operations are performed for spot welds, then complete connection is achieved, but production time increases

Engineering Contradiction:
Improvecomplete connectionVSAvoidproduction time
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent merges multiple discrete welding operations into a single continuous welding pass. By using a welding torch that moves continuously around the circumference and a capacitor bank that can be recharged and discharged in sequence, the system achieves complete circumferential welding in one continuous operation rather than multiple separate spot welding steps.

Inventive Principle:
Principle #5Merging (Combining)

4Strength

If circumferential flanges are added to lock cap bodies, then welding connection is improved, but assembly space requirements increase

Engineering Contradiction:
Improvewelding connectionVSAvoidassembly space
Core Design Contradiction:
StrengthVSArea of stationary object

Solution Approach 1:

The patent extracts and eliminates the circumferential flanges from the lock cap body design. By using capacitor discharge welding and continuous circumferential welding techniques, the invention achieves strong welding connections directly on the basic lock cap surfaces without requiring additional flange structures, thereby reducing the overall size and assembly space requirements of the lock mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

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 method reduces heat-induced damage, enhances the lock's resistance to breaking, and allows for a more compact design that fits better on limited spaces, with a single current surge forming a continuous, firm connection that is difficult to break.

Implementation Method 1

both at the lock cap legs, formed by the assembly of the front lock cap legs and the rear lock cap legs, and at the lock cap body, formed by the assembly of the front lock cap body and the rear lock cap body, at least one contact surface as mentioned is present at which, following the capacitor discharge weld process, a capacitor discharge weld connection is formed

Methodology Applied
Scientific EffectCapacitor discharge welding: Electric Arc

Data Source

PatentEP2962920B1Ring lock and method for manufacturing a ring lock
Publication Date: 2021.01.13 ALLEGION NETHERLANDS BV
  • EP2962920B1 patent drawingFigure 1~2
  • EP2962920B1 patent drawingFigure 3~5a
  • EP2962920B1 patent drawingFigure 6~7a

AI summary

A ring lock (1) provided with a lock housing with a lock assembly included therein and a bolt (11). Further, the ring lock (1) includes a front lock cap (2) with two front lock cap legs (4A) which are connected with a front lock cap body (5A) and a rear lock cap (3) with two rear lock cap legs (4B) which are connected with a rear lock cap body (5B). In a mounted condition the lock housing and the bolt (11) are at least partly included between the front lock cap (2) and the rear lock cap (3), the front lock cap (2) and the rear lock cap (3) being connected with each other at contact surfaces by at least one capacitor discharge weld connection. Also described is a method for manufacturing such a lock.