Stackable Trolley Backrest Segmented Reinforcement

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Solution Overview

Problem

Existing stackable transport trolleys and child seats lack stability and durability, particularly during use and storage, with complex designs and high production costs.

Innovation Solution

A stackable transport trolley with a pivoting plastic backrest and a wire frame support system that includes U-shaped wire brackets and basket fastening brackets, allowing for easy assembly and cost-effective production while ensuring stability and load distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a plastic backrest with reinforcing struts is used, then stability and durability are improved, but manufacturing complexity increases

Engineering Contradiction:
Improvestability and durabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The backrest is divided into multiple spars (first spar, second spar, third spar, fourth spar) with reinforcing struts integrated into each. This segmentation allows the complex structure to be manufactured as a single injection-molded piece while maintaining modular characteristics that simplify the molding process and tooling requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The backrest combines plastic material with integrated reinforcing struts to create a composite structure. The plastic provides the basic form and flexibility, while the reinforcing struts (integrated as part of the plastic structure) provide additional strength and stability, achieving high reliability without requiring separate metal reinforcement pieces.

Inventive Principle:
Principle #40Composite materials

2Strength

If a hollow body structure with reinforcing struts is used, then strength is improved, but production cost increases

Engineering Contradiction:
ImprovestrengthVSAvoidproduction cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The hollow body structure is segmented into multiple spars with reinforcing struts, allowing the complex strengthened structure to be manufactured as a single injection-molded piece. This eliminates the need for separate manufacturing processes for the hollow sections and reinforcements, reducing production costs despite the increased strength requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design changes the physical parameters of the backrest by creating hollow sections and integrating reinforcing struts within the plastic structure. These parameter changes (hollow geometry, internal reinforcement placement) are achieved through injection molding technology, which can produce complex geometries at low per-unit cost once tooling is established, thereby improving strength without significantly increasing production cost.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the backrest is made in one piece, then manufacturing simplicity is improved, but structural stability may worsen

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidstructural stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The one-piece plastic backrest incorporates reinforcing struts as an integral part of the molded structure. This composite approach (plastic matrix with embedded reinforcement geometry) allows the single-piece construction to achieve the structural stability of multi-component designs while maintaining the manufacturing simplicity of injection molding, as the reinforcements are formed simultaneously with the main body.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The backrest is segmented into multiple functional spars (first, second, third, fourth spars) with reinforcing struts distributed throughout. This segmentation is achieved within a single-piece molded construction, allowing the complex stable structure to be produced as one piece through carefully designed injection molding that creates all structural elements in a single manufacturing step.

Inventive Principle:
Principle #1Segmentation

4Quantity of substance

If hollow spaces are provided between reinforcing struts, then material efficiency is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvematerial efficiencyVSAvoidmolding precision
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The design changes the material distribution parameters by creating hollow spaces between reinforcing struts. This reduces the quantity of plastic material required while maintaining structural integrity. The hollow geometry is achieved through injection molding parameters and tooling design that control material flow and solidification, transforming a potential precision challenge into a routine manufacturing feature.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The backrest structure is segmented into hollow sections between the reinforcing struts, creating a lattice-like configuration. This segmentation reduces overall material usage while the single-piece injection molding process ensures precise formation of all hollow sections and their interconnections, maintaining manufacturing simplicity despite the complex internal geometry.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3708460B1Transport trolley with child seat
Publication Date: 2024.03.06 WANZL GMBH & CO KGAA
  • EP3708460B1 patent drawingFigure 1
  • EP3708460B1 patent drawingFigure 2
  • EP3708460B1 patent drawingFigure 3

AI summary

The present invention relates to a child seat (80) for a stackable transport trolley (10), in particular a stackable transport trolley (10) with a backrest (84) made of plastic, which is pivotable about a horizontal axis (90) on the shopping trolley (10), to which at least one seat (82) is coupled in a sliding or pivoting manner, wherein the backrest (84) is formed in one piece and wherein at least a partial section of the backrest (84) is formed in a hollow body shape.