Coupling Unit for Lattice Structure Connector Alignment

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Solution Overview

Problem

The existing methods for joining lattice structures in large work machines, such as cranes, face issues with thermal strain causing misalignment of connectors, which can lead to failed connections and reduced production efficiency due to the need for large equipment and residual strain after welding.

Innovation Solution

The use of connector interconnection members to accurately determine the relative positions of connectors without welding them directly to the main pipes, instead joining them to the connectors, allows for precise alignment and stable connections, reducing the impact of thermal strain and eliminating the need for heavy equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If welding is performed to join connectors to main pipes, then strong connections are achieved, but thermal strain causes misalignment of connectors

Engineering Contradiction:
Improveconnection strengthVSAvoidconnector alignment
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The connection system is divided into two independent parts: the welding connection between main pipes and connectors, and the mechanical connection between connectors and coupling units. This segmentation allows the welding process to focus on strength while the mechanical connection handles alignment precision, resolving the contradiction between connection strength and alignment precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling units are pre-assembled with connectors attached via mechanical connection before the main pipe welding occurs. This preliminary action establishes the alignment and relative positions of connectors before thermal strain from welding can cause misalignment, thereby maintaining manufacturing precision while still achieving strong connections.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If large pressing cylinders are used to fix connector positions during welding, then alignment is maintained, but equipment complexity and production time increase

Engineering Contradiction:
Improveconnector position stabilityVSAvoidpressing equipment
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The mechanical connection structure acts as an intermediary between connectors and coupling units, providing position fixation without requiring large pressing cylinders. The mechanical connection inherently maintains alignment while allowing for easier assembly and disassembly, eliminating the need for complex pressing equipment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If connectors are welded and then pin holes are formed, then connection strength is ensured, but production efficiency decreases

Engineering Contradiction:
Improvewelding connection strengthVSAvoidproduction efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The mechanical connection and pin hole formation are performed as preliminary actions before the welding process. By establishing the connection structure and alignment beforehand, the subsequent welding only needs to provide additional strength without requiring repositioning or re-drilling, thereby maintaining both connection strength and production efficiency.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If axial force is continuously applied during welding, then connector alignment is maintained, but residual strain causes displacement after force release

Engineering Contradiction:
Improveconnector alignment during weldingVSAvoidconnector position stability after welding
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The position fixation function is extracted from the welding process itself and implemented through the separate mechanical connection structure. This allows alignment to be established independently of the welding thermal cycle, preventing residual strain from causing displacement after welding completion.

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 solution ensures reliable and long-term connections between connectors, maintaining alignment even under torsional loads, and reduces the complexity and weight of the lattice structure, enhancing production efficiency and durability.

Implementation Method 1

at least one connector interconnection member that interconnects the plurality of connectors

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 2

a fitted part capable of being fitted to an end of the main pipe corresponding to the connector

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3444219B1Coupling unit for a lattice structure constituting a work machine
Publication Date: 2022.12.28 KOBELCO CONSTR MASCH CO LTD
  • EP3444219B1 patent drawingFigure 1
  • EP3444219B1 patent drawingFigure 2
  • EP3444219B1 patent drawingFigure 3

AI summary

Provided is a coupling unit (60A) capable of accurately determining a relative position between connectors despite welding across main pipes and connectors in a lattice structure. A coupling unit (60A) includes connectors (62A) to be joined to ends (52a) of main pipes (52), and a connector interconnection member (64) that interconnects connectors (62A) to one another. Each of the connectors (62A) includes: a fitted part (67) fittable to the end (52a) of the main pipe (52); a detachable connection part (68) detachably connectable to a counterpart connector (62B) provided to an end of the other lattice structure (16C); an outer peripheral surface (66a) weldable to an outer peripheral surface of the end (52a) of the main pipe (52) while the fitted part (67) is fitted to the end (52a) of the main pipe (52); and a connected part to which an end of the connector interconnection member (64) is to be connected.