Eccentric Lifting Arrangement for Horizontal Pallet Stability

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Solution Overview

Problem

Current storage and retrieval systems face challenges in efficiently lifting and moving heavy pallets between different levels and positions within a storage hall while maintaining a horizontal position, especially when interacting with elevators and conveyor systems, as existing solutions often require complex directional changes and risk tilting or sliding issues.

Innovation Solution

A lifting arrangement featuring a drive shaft with eccentrics and linkage systems that enable synchronized reciprocating movement of a carrier plate, allowing for controlled, horizontal up-and-down movement without directional changes, utilizing freely rotating wheels and guiding devices to maintain horizontal orientation and prevent sideways movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional lifting mechanism is used to lift heavy pallets, then lifting capability is achieved, but the pallet may tilt or slide during movement

Engineering Contradiction:
Improvestability of pallet during liftingVSAvoidcomplexity of lifting mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs curved guide surfaces and rounded contact points in the lifting mechanism that conform to the pallet structure, ensuring smooth engagement and preventing tilting during vertical movement. The curved paths guide the pallet through a controlled trajectory that maintains horizontal orientation.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent introduces intermediate guide elements and positioning devices between the lifting mechanism and the pallet. These intermediary components act as mediators that transfer the lifting force while maintaining pallet stability and preventing sideways movement through guided constraints.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the lifting mechanism allows directional changes for maneuverability, then adaptability is improved, but the risk of tilting or sliding increases

Engineering Contradiction:
Improvemaneuverability of lifting mechanismVSAvoidhorizontal stability of pallet
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The lifting mechanism is divided into separate functional segments: a vertical lifting section that maintains horizontal orientation, and separate horizontal transport sections for maneuverability. This segmentation allows directional changes to occur only in the transport sections, while the lifting section maintains strict vertical movement to prevent tilting.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent separates the degrees of freedom by allowing horizontal maneuvering in the x-y plane while constraining the lifting motion to the z-axis only. This dimensional separation ensures that adaptability for positioning is achieved without compromising the horizontal stability during vertical movement.

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

3Productivity

If existing lifting systems are used, then basic lifting function is achieved, but complex directional changes are required

Engineering Contradiction:
Improveefficiency of pallet transferVSAvoidnumber of directional changes required
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the vertical lifting function with horizontal positioning capabilities into an integrated mechanism. The lifting arrangement is merged with guide rails and positioning devices that enable direct vertical movement combined with minimal horizontal adjustment, eliminating the need for separate directional change operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system performs preliminary positioning and alignment of the pallet before lifting begins. Guide elements pre-align the pallet in the horizontal plane, and the lifting mechanism is pre-positioned to receive the pallet vertically, eliminating the need for complex directional changes during the actual lifting operation.

Inventive Principle:
Principle #10Preliminary action

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

Enables secure, efficient, and controlled lifting of heavy loads between different levels and positions within a storage and retrieval system, ensuring horizontal movement and reducing the risk of tilting or sliding, thus improving operational efficiency and safety.

Implementation Method 1

a lifting drive shaft having a first end and a second end, a lifting driving arrangement connected to the lifting drive shaft for rotating the lifting drive shaft, and a first and a second eccentric, the first eccentric being fixed to the first end of the lifting drive shaft and the second eccentric being fixed to the second end of the lifting drive shaft

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Data Source

PatentEP3418220B1A transport cart of a storage and retrieval system and a lifting arrangement for such a transport cart
Publication Date: 2021.07.21 SWISSLOG ACCALON AB
  • EP3418220B1 patent drawingFigure 1
  • EP3418220B1 patent drawingFigure 2
  • EP3418220B1 patent drawingFigure 3a

AI summary

Lifting arrangement comprising a lifting drive shaft (20), a lifting driving arrangement (30, 32) for rotating the lifting drive shaft (20), and first and second eccentrics (34) fixed to opposite ends of the lifting drive shaft (20), a first and a second linkage system (40, 60), each having a first part (41) and a second part (51) connected via a link arm (50). The first and the second parts (41, 51) are each rotatably mounted to a transport cart (1), whereby a periphery (34b) of the eccentrics (34) bears against the first part (41) of the respective first and second linkage system (40, 60) so that when the lifting drive shaft (20) rotates the first and the second eccentric (34, 35), the periphery of the first and second eccentric (34) urges a reciprocating movement onto the respective first and second linkage system (40, 60).