Concrete Pump Distribution Mast Arm With Corner Supports

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Solution Overview

Problem

Existing distributor mast arms in mobile concrete pumps face issues with high local stresses in corners due to torsional loads, leading to reduced load-bearing capacity and increased mass, while current solutions either increase material thickness uniformly or result in inefficient material utilization.

Innovation Solution

The distributor mast arm incorporates support profiles with varying wall thickness and/or diameter, featuring tubes or solid profiles at corners, connected to side plates in a bonded and force-transmitting manner, reducing stress concentrations and allowing for optimized material distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thicker side plates are used to counteract high stresses in corners, then load-bearing capacity is improved, but mass increases disproportionately

Engineering Contradiction:
Improveload-bearing capacityVSAvoidmass of distributor mast arm
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies local quality by placing support profiles specifically at corner locations where high stresses occur, rather than uniformly thickening the entire side plates. The support profiles have varying wall thicknesses and/or diameters along their length, with thicker sections at high-stress locations and thinner sections elsewhere, optimizing material distribution to provide strength exactly where needed while minimizing overall mass.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If uniform material thickness is used throughout the side plates, then manufacturing is simplified, but material utilization becomes inefficient

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmaterial waste
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The support profiles feature varying wall thicknesses and/or diameters along their length, with thicker sections positioned at high-stress locations (such as corners) and thinner sections in low-stress areas. This localized variation in material thickness optimizes material utilization by concentrating material where structurally necessary while reducing material in non-critical areas, thereby minimizing material waste without compromising strength.

Inventive Principle:
Principle #3Local quality

3Reliability

If corner is formed as a single piece with side plate and rounded, then weld seam shifts to less stressed areas, but stiffness is reduced due to economic constraints on wall thickness

Engineering Contradiction:
Improveweld seam positioningVSAvoidstiffness of corner
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent employs composite construction by combining side plates with separately attached support profiles at the corners. This composite approach allows the support profiles to be optimized independently for both stiffness and stress distribution, achieving high stiffness at corners through the combined structural effect while maintaining economical wall thicknesses. The support profiles with varying cross-sections provide enhanced moment of inertia at critical locations without requiring uniform thickening throughout.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP4428325B1Distribution mast arm
Publication Date: 2025.11.05 LIEBHERR MISCHTECHN
  • EP4428325B1 patent drawingFigure 1
  • EP4428325B1 patent drawingFigure 2
  • EP4428325B1 patent drawingFigure 3

AI summary

The invention relates to a placing boom arm for a concrete pump, in particular a mobile concrete pump, wherein the placing boom arm comprises a support structure with at least two side walls and wherein the support structure further comprises a support profile. According to the invention, at least two side walls are arranged on the support profile, wherein the support profile is arranged in a corner of the support structure.