U-Shaped Rail Arrangement for Stacker Crane Space Optimization

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Solution Overview

Problem

Existing stacker cranes face limitations in utilizing installation space efficiently for storage areas, as the rail arrangement typically restricts the downward movement and reach of storage and retrieval devices, especially when trying to access low-lying areas on shelves.

Innovation Solution

The rail arrangement is configured with a U-shaped recess, allowing the track to be positioned lower than conventional designs, with the running gear embedded within, and using an aluminum extruded profile that eliminates the need for section connections, enabling cost savings and improved stability through guide rollers and a decoupled drive belt system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the rail arrangement uses conventional steel girder design with flanges, then the structure provides sufficient support strength, but the track cannot be positioned low enough to access low-lying shelf areas

Engineering Contradiction:
Improvereach depthVSAvoidsupport strength
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The patent changes the fundamental parameter of track positioning height by using a U-shaped recess configuration that allows the track to be positioned at the bottom rather than at the top or middle of the rail assembly. This enables the storage and retrieval device to reach lower areas on shelves (up to 100-200mm lower) while the base plate and support flanges provide the necessary structural strength to counteract tilting moments.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the rail arrangement is widened to accommodate all components, then all functions are properly supported, but the installation space is wasted

Engineering Contradiction:
Improvefunctional reliabilityVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges multiple functions into a compact U-shaped recess configuration. The side walls provide both structural support and guidance for the running gear, the base plate serves as both a mounting surface and a structural element to counteract tilting moments, and the support flanges are integrated into the same profile. This integration eliminates the need for separate components and reduces the overall width of the rail arrangement.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent repositions components from a horizontal arrangement to a vertical arrangement within the U-shaped recess. The track is positioned at the bottom, support flanges are positioned above, and side walls extend vertically to provide guidance. This vertical stacking of functions within a compact horizontal footprint maximizes space utilization.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If aluminum extruded profiles are used instead of steel girders, then manufacturing precision and straightness are improved, but the ability to connect sections is lost

Engineering Contradiction:
ImprovestraightnessVSAvoidsection connection
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent divides the rail arrangement into multiple separable aluminum extruded profile sections that can be connected end-to-end. Each section maintains the U-shaped recess configuration and can be independently manufactured with high precision. The segmentation allows for easy assembly and disassembly while maintaining the manufacturing precision benefits of extrusion profiles.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3336048B1Shelf serving device
Publication Date: 2022.12.28 JUNGHEINRICH AG
  • EP3336048B1 patent drawingFigure 1~2
  • EP3336048B1 patent drawingFigure 3~4

AI summary

A storage and retrieval machine (1) is described, comprising a carriage (2) supported by a roller assembly (11) on a track (10) of a rail assembly (3) and engaging a flange assembly (20, 21) of the rail assembly (3) by means of an arrangement of support wheels (22, 23). The aim is to utilize the available installation space in a rack as efficiently as possible. Therefore, the track (10) is arranged below the flange assembly (20, 21) in the direction of gravity.