Stackable Shopping Trolley Foldable Shelf Weighing Unit

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Solution Overview

Problem

Existing stackable shopping trolleys with weighing units cannot incorporate a foldable goods shelf without compromising stackability or requiring additional load cells.

Innovation Solution

The shopping cart design features load cells arranged at the top of the chassis, supporting the basket via at least two load cells, and includes a foldable goods tray suspended from the shopping item receiving unit without touching the chassis, allowing weight detection without additional weighing units or load cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a foldable goods shelf is added to a stackable shopping trolley with weighing unit, then the versatility and customer convenience are improved, but the stacking dimension increases and stackability is compromised

Engineering Contradiction:
Improvegoods storage capabilityVSAvoidstacking dimension
Core Design Contradiction:
Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The foldable goods shelf is designed to nest within the basket structure when folded, similar to a nested doll configuration. The shelf components are positioned inside the basket's internal volume, allowing the shopping trolley to maintain its original external dimensions and stacking capability while providing additional storage functionality when needed.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The goods shelf is designed with dynamic folding and unfolding capabilities, allowing it to change its spatial configuration. When folded, the shelf occupies minimal space within the basket; when unfolded, it provides extended storage capacity. This dynamic transformation enables the system to adapt between compact storage mode for stacking and expanded mode for additional goods storage.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a foldable goods shelf is added to a shopping trolley with weighing unit, then the goods storage capacity is improved, but additional load cells are required which increases device complexity

Engineering Contradiction:
Improvegoods storage capacityVSAvoidweighing unit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The existing load cells in the shopping trolley are designed to serve multiple functions: they measure the weight of goods in the basket and also detect the presence and weight of goods on the foldable shelf. By positioning the shelf such that its movement and loading affect the same load measurement points, the system uses the existing weighing infrastructure for dual purposes, avoiding the need for separate load cells for the shelf.

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

Solution Approach 2:

The weighing function for the basket and the foldable shelf is merged into a single measurement system. The load cells are positioned to detect forces from both the basket contents and the shelf contents simultaneously, combining these measurement functions into one integrated weighing mechanism rather than using separate sensing systems.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If the shopping item receiving unit is mounted on load cells for weighing, then the weighing function is achieved, but the support structure cannot accommodate a foldable shelf without additional load cells

Engineering Contradiction:
Improveweight detection accuracyVSAvoidsupport structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The foldable shelf is extracted from the main support structure and designed as a separate, independently movable component. The shelf is positioned such that when folded, it does not interfere with the load cell measurements of the basket. This separation allows the weighing function to remain accurate while the shelf provides additional storage without requiring integration into the load-bearing support structure.

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 design enables the provision of a foldable goods shelf in stackable shopping trolleys with weighing units, maintaining a small stacking dimension and allowing comfortable placement of goods at knee height or lower, without the need for additional load cells or changes to the support structure.

Implementation Method 1

The shopping item receiving unit, which forms the most important part of the shopping cart, is arranged entirely above the chassis and supported on the chassis via at least two, in particular three load cells

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 2

support elements are preferably provided on both sides, which extend laterally and downwards from the outside of the shopping article receiving unit, with a pivot bearing for the goods storage being formed at the bottom of each of the support elements

Methodology Applied
Scientific EffectLever: Lever

Data Source

PatentEP4563441A1Stackable shopping trolley with a weighing unit
Publication Date: 2025.06.04 J D GECK
  • EP4563441A1 patent drawingFigure 1
  • EP4563441A1 patent drawingFigure 2
  • EP4563441A1 patent drawingFigure 3

AI summary

A stackable shopping cart (100) with a weighing unit (140), comprising at least - a chassis (120) comprising two pairs of supports (121, 122) which are spread out forwards and/or backwards and each provided with at least one roller (123), which join in pairs at an upper vertex (124), - the weighing unit (140) comprising at least one electronic evaluation device and at least two load cells (141, 142); - a shopping item receiving unit (130) which is mounted on the chassis (120) via the load cells (141, 142) arranged underneath, characterized in that a foldable goods shelf is provided at the rear of the shopping cart, which hangs only on the shopping item receiving unit (130) without touching the chassis (120).