Jib Connection Structure With Variable Pin Gap

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Solution Overview

Problem

The existing jib connection structures face issues where the boom naturally extending interferes with the insertion of pins into the jib connection shaft, preventing the jib base end engagement portions from being connected, and excessive clearance leads to sideways swinging of the jib during projection.

Innovation Solution

A jib connection structure with a gap formed between the pin and the jib connection shaft allows for connection even during natural boom extension, and the pin's position is adjusted to minimize clearance when the jib is projected, preventing sideways swinging by ensuring the pin is in contact or has a small clearance with the jib connection shaft.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If clearance is provided between the pin and the jib connection shaft to prevent interference during natural boom extension, then the pin can be inserted even when the boom naturally extends, but the jib may swing sideways when projected

Engineering Contradiction:
Improveconnection reliabilityVSAvoidjib stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The pin is designed to be movable relative to the jib connection shaft, transitioning from a fixed position to a dynamic position that adjusts based on operational state. The pin can move along the jib connection shaft to accommodate natural extension while maintaining connection reliability, and can be repositioned to minimize clearance when the jib is projected to prevent sideways swinging.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The clearance parameter between the pin and jib connection shaft is made variable rather than fixed. The clearance is enlarged during natural extension to allow pin insertion, and then reduced when the jib is projected to prevent swinging. This dynamic parameter adjustment resolves the contradiction between connection reliability and jib stability.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the pin is positioned to minimize clearance for preventing jib swinging, then jib stability is improved, but the pin cannot be inserted when the boom naturally extends

Engineering Contradiction:
Improvejib stabilityVSAvoidconnection reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The pin is designed with movable capability along the jib connection shaft, allowing it to adapt its position dynamically. During natural extension, the pin can be positioned to allow insertion, and during projection, it can be repositioned to minimize clearance and prevent swinging, thus resolving the contradiction between stability and reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The pin is preliminarily positioned with sufficient clearance to accommodate natural extension before the projection operation begins. This preliminary positioning ensures that the connection can be established even when the boom naturally extends, and then the pin is repositioned to minimize clearance for stable operation during projection.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3272695B1Jib connection structure
Publication Date: 2020.02.26 TADANO LTD
  • EP3272695B1 patent drawingFigure 1
  • EP3272695B1 patent drawingFigure 2
  • EP3272695B1 patent drawingFigure 3

AI summary

Provided is a jib connection structure that is capable of connecting a jib base end engagement part and a jib connection shaft even when a boom undergoes natural extension, and that is capable of restraining a jib from swinging sideways in a state where the jib is projected. This jib connection structure comprises: jib connection shafts (21, 22) projecting horizontally toward both sides from a boom tip end part (14a); and jib base end engagement parts (31, 32) respectively provided to bifurcated jib base end parts (15a). Each jib base end engagement part (31, 32) is U-shaped into which the jib connection shaft (21, 22) can be fitted, and is provided with an insertion hole (31h, 32h) into which a pin (33, 34) for preventing the jib connection shaft (21, 22) from slipping out is inserted. The insertion hole (32h) in one jib base end engagement part (32) is arranged more toward the outside than a U-shaped bottom part (32b). When the jib base end engagement part (32) and the jib connection shaft (22) are connected, a gap (d1 is formed between the pin (34) and the jib connection shaft (22). When a jib (14) is projected, the gap (d2) between the pin (34) and the jib connection shaft (22) becomes smaller.