Split Collet Fastener Feeding for Recessed Resistance Welding

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Solution Overview

Problem

Existing methods for fastening work pieces, such as spot welding and self-piercing rivets, require feeding systems for rivets that are not efficient in multiple axes and often face challenges with access to recesses.

Innovation Solution

A resistance welding fastener feeding apparatus with a split collet and actuator system that allows for axial movement of the collet relative to the upper electrode, enabling the feeding and installation of fasteners into recesses by opening and closing around the fastener, and retracting to expose the electrode for welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional feeding systems are used for self-piercing rivets, then fastening work pieces can be achieved, but the system is not efficient in multiple axes and faces challenges with access to recesses

Engineering Contradiction:
Improvemulti-axis capabilityVSAvoidaccess to recesses
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The collet is made movable relative to the electrode, allowing it to dynamically adjust its position. The collet can move into engagement with the fastener, hold it in position, and then retract to allow electrode access to the workpiece. This dynamic movement enables both multi-axis capability and access to recesses that would be inaccessible to static feeding systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The collet serves as an intermediary component between the fastener delivery system and the electrode. It temporarily holds the fastener and transfers it to the electrode, enabling precise positioning and control. This intermediary mechanism allows the system to handle fasteners in multiple axes while maintaining the ability to access recessed areas.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the collet holds the fastener in position, then alignment is maintained, but the electrode must be exposed for welding requiring retraction

Engineering Contradiction:
ImprovealignmentVSAvoidretraction mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The collet's ability to move relative to the electrode creates a dynamic system where alignment and exposure requirements are sequentially satisfied. The collet moves into position to establish precise alignment, then retracts to expose the electrode for welding. This dynamic behavior resolves the contradiction between maintaining alignment and enabling electrode access.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The collet performs periodic cycles of engagement and retraction. During each cycle, it first engages to hold and align the fastener, then retracts to allow welding, and finally re-engages for the next fastener. This periodic action pattern allows the system to alternately satisfy alignment requirements and electrode exposure requirements.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3723931B1Resistance welding fastener feeding apparatus
Publication Date: 2026.03.18 HOWMET AEROSPACE INC
  • EP3723931B1 patent drawingFigure 1
  • EP3723931B1 patent drawingFigure 2
  • EP3723931B1 patent drawingFigure 3A~3B

AI summary

A collet assembly including an actuator and a collet connected to the actuator. The collet assembly is adapted to be installed on a welding electrode holder having an electrode. The collet is moveable by the actuator from an advanced position, in which the collet is adapted to grip a fastener such as a welding rivet, and a retracted position, in which at least a portion of the collet is retracted into the actuator to enable the electrode to engage the fastener for welding to a work piece, and the collet is adapted to release the fastener.