Dolly Coupling Arrangement with Self-Aligning Guide Surface

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Solution Overview

Problem

Existing coupling systems for dollies require precise guidance to connect, making it difficult to position the drawbar and hook, especially with heavy loads, leading to awkward working positions and potential damage or injury.

Innovation Solution

A coupling arrangement featuring a female connecting part with a large sliding area and guide surface, and a male connecting peg with a knob, allowing easy alignment and automatic guidance, enabling connection without manual precision and minimizing protruding parts to prevent entanglement or collision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the coupling means are positioned under the body of the dolly, then the coupling mechanism is protected from damage, but it becomes difficult to see and position the coupling hook and slot, requiring awkward bending positions

Engineering Contradiction:
Improveprotection of coupling mechanismVSAvoidease of positioning coupling parts
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The coupling mechanism is positioned in the longitudinal dimension under the dolly body for protection, while the drawbar operates in the vertical dimension (lifted position) for easy access. This dimensional separation allows the coupling parts to be protected when not in use while remaining easily accessible during operation.

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

Solution Approach 2:

The drawbar is designed to be movable between a lifted position (for easy access and coupling) and a lowered position (for engagement with the hook). This dynamic positioning allows the system to switch between protection mode and operation mode, resolving the contradiction between safety and ease of operation.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the hook is positioned outside the outer reach of the rear surface of the trolley for easier positioning, then alignment is improved, but the hook may hit goods, people, or obstacles, causing damage or injury

Engineering Contradiction:
Improveease of positioning drawbarVSAvoidrisk of collision and injury
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The drawbar is designed to be in a lifted position during normal operation, keeping it clear of the dolly body and goods. When coupling is needed, the drawbar is lowered to engage with the hook. This dynamic positioning eliminates the risk of the drawbar protruding and causing collision while maintaining ease of positioning.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The connecting elements (drawbar and hook) are extracted from the main body structure and positioned separately. The drawbar can be lifted clear of the dolly body, and the hook is recessed into the body, ensuring that neither element protrudes to cause harm while remaining accessible for coupling operations.

Inventive Principle:
Principle #2Taking out (Extraction)

3Manufacturing precision

If precise manual guidance is required to connect the drawbar and hook, then connection accuracy is achieved, but the operation becomes difficult and time-consuming, especially with heavy loads

Engineering Contradiction:
Improveprecision of coupling connectionVSAvoidspeed of coupling operation
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The coupling mechanism is designed to be self-aligning through the guide surface that directs the connecting element into the receiving element. The geometry of the guide surface and recess automatically guides the drawbar into proper alignment with the hook, eliminating the need for precise manual guidance while maintaining connection accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

A guide surface is introduced as an intermediary element between the drawbar and the hook. This guide surface provides automatic alignment and direction, mediating the connection process to ensure precise engagement without requiring manual positioning, thus resolving the contradiction between precision and speed.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2646308B1Coupling arrangement for a dolly and a dolly
Publication Date: 2018.03.21 K HARTWALL OY AB
  • EP2646308B1 patent drawingFigure 1~2
  • EP2646308B1 patent drawingFigure 3
  • EP2646308B1 patent drawingFigure 4~5

AI summary

Coupling arrangement for a dolly, and a dolly equipped with such an arrangement, comprising a female connecting part and a male connecting part. The male connecting part comprises a draw bar (6) and a connecting peg (9) and the female part comprises an at least partially closed recess having an area limited by at least partially closed wall (15 - 18) having a height and comprising at least a concave guiding part (15) and a ceiling (26) positioned to form the at least partially closed recess with the wall (15 - 18), and a hole (20) in the ceiling (26) at the tip (16) of the concave part (15) of the wall (15 - 18) and dimensioned to receive the connecting peg (9).