Self-Actuating Tension Head for Coated Steel Strapping

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Solution Overview

Problem

Current steel strap welding processes are labor-intensive and inefficient, particularly when dealing with coated straps, as they require stripping the coating for welding, which compromises joint strength and is time-consuming, and there is a need for an automated solution that can tension and seal steel straps without crimp-type seals and without removing the coating.

Innovation Solution

A self-actuating tension head for a strapping machine that includes a drive wheel, tension wheel, and pinch wheel system, allowing for automatic tensioning and sealing of steel straps around loads, with modular components for quick maintenance and operation, enabling welding of coated straps without surface preparation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If spot welding is used on coated steel strap, then welding can be performed without coating removal, but joint strength cannot be consistently maintained

Engineering Contradiction:
Improvewelding speedVSAvoidjoint strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The invention extracts and removes the coating from the steel strap surface at the welding location using a cutting wheel or abrasive wheel, exposing the bare metal substrate. This allows for consistent spot welding while maintaining productivity, as the coating removal is integrated into the welding process rather than being a separate preparation step.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The coating removal is performed as a preliminary action immediately before welding. The system automatically removes the coating at the welding location just prior to applying the weld, ensuring the metal surface is clean and ready for welding without requiring manual intervention or separate preparation steps.

Inventive Principle:
Principle #10Preliminary action

2Strength

If manual coating removal is performed before welding, then joint strength can be maintained, but the process becomes time consuming and labor intensive

Engineering Contradiction:
Improvejoint strengthVSAvoidpreparation time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The invention merges the coating removal operation with the welding operation into a single integrated process. The cutting wheel or abrasive wheel is positioned adjacent to the welding electrodes, allowing coating removal and welding to occur in sequence without interruption or manual intervention, thereby maintaining joint strength while eliminating preparation time losses.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system performs coating removal automatically as part of the welding cycle without requiring manual labor. The mechanical cutting or abrasive removal is driven by the machine itself, making the process self-service and eliminating the need for separate manual coating removal steps.

Inventive Principle:
Principle #25Self-service

3Reliability

If crimp-type seals are used on steel strap, then sealing can be achieved, but the process requires additional components and steps

Engineering Contradiction:
Improvesealing reliabilityVSAvoidsealing mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the crimp-type seal component from the strapping system. Instead of using a separate seal element that requires crimping, the system relies on the welded joint itself to provide both the connection and sealing function, thereby reducing device complexity while maintaining sealing reliability through the strength of the weld.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The welded joint serves multiple functions simultaneously: it provides structural connection, tension resistance, and sealing. By making the weld itself multi-functional, the invention eliminates the need for separate seal components, reducing overall system complexity while maintaining reliable sealing performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 automates the tensioning and sealing of steel straps, ensuring consistent joint strength without the need for coating removal, reducing labor and time, and allowing for quick replacement of machine components to minimize downtime.

Implementation Method 1

a drive wheel defining an axis of rotation and a tension wheel defining an axis of rotation... The drive and tension wheels are operably engaged with one another

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

Welding steel strap is also known, but is currently only done using spot weld and inert-gas (i.e., TIG) welding processes

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP2841344B1Tension head for modular steel strapping machine
Publication Date: 2016.09.28 SIGNODE INTERNATIONAL IP HOLDINGS LLC
  • EP2841344B1 patent drawingFigure 1
  • EP2841344B1 patent drawingFigure 2
  • EP2841344B1 patent drawingFigure 3

AI summary

A self-actuating tension head for a strapping machine includes a body defining a strap path, a drive wheel, a tension wheel a fixed distance from the drive wheel and a pinch wheel. The strap path extends between the tension and pinch wheels. A first link operably connects the drive and tension wheels and defines a first pivot arm that is pivotable about the drive wheel axis of rotation. A second link operably connects the tension and pinch wheels and defines a second pivot arm that is pivotable about the pinch wheel axis and movable along the second pivot arm to move the tension wheel into and out of engagement with the pinch wheel. The first and second pivot arms define an energizing angle therebetween that decreases as the tension wheel is moved into engagement with the pinch wheel and increases as the tension wheel is moved out of engagement with the pinch wheel.