Fork Carriage Pantograph Linkage Reduces Overhang

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Solution Overview

Problem

Existing fork carriages with pantograph linkages for truck mounted forklifts require a tall upright forward section, which prevents engagement of top far side loads due to roof obstruction and increases overhang, leading to inefficiencies in loading and unloading operations and potential weight and stability issues.

Innovation Solution

A fork carriage design with a shorter upright forward section and a pantograph linkage system comprising multiple interconnected arms with pivot and hinge joints, allowing for a compact retracted configuration and horizontal movement of tines, reducing overhang and enabling access to top far side loads without roof interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a tall upright forward section is used in the fork carriage, then the bearing at the end of the pantograph linkage arm can travel upwards when the pantograph is retracted, but the fork carriage is prevented from engaging top far side loads by the roof of the carrying vehicle and increases overhang

Engineering Contradiction:
Improvepantograph linkage operationVSAvoidloading and unloading operation efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent changes the movement dimension of the bearing from vertical (upwards travel) to horizontal (along the upright forward section). The bearing is slidably mounted on the upright forward section, allowing it to move horizontally instead of vertically. This dimensional change enables the pantograph to retract without requiring a tall upright forward section, thus avoiding roof obstruction while maintaining full operational capability.

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

2Ease of operation

If a tall upright forward section is used in the fork carriage, then the pantograph linkage can be fully retracted, but the overhang from the rear of the carrying vehicle increases

Engineering Contradiction:
Improvepantograph linkage retractionVSAvoidoverhang from carrying vehicle
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The patent changes the bearing movement from vertical to horizontal along the upright forward section. This allows the pantograph to achieve full retraction with a shorter upright forward section, thereby reducing the overall overhang of the forklift from the carrying vehicle without compromising the retraction capability.

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

3Strength

If the forklift is made heavier to reinforce the forks for greater overhang forces, then the forks can handle greater forces during transit and mounting/dismounting, but the carrying capacity of the carrying vehicle is reduced

Engineering Contradiction:
Improvefork strengthVSAvoidforklift weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

By changing the bearing movement to horizontal along the upright forward section, the patent enables a shorter upright forward section. This reduces the overhang and consequently the forces on the forks during transit and mounting/dismounting. The reduced forces allow the use of lighter fork material while maintaining sufficient strength, thus reducing the overall forklift weight and preserving carrying vehicle capacity.

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

Data Source

PatentEP3599215B1A fork carriage for a truck mounted forklift
Publication Date: 2021.11.03 MOFFETT RES & DEV
  • EP3599215B1 patent drawingFigure 1(i)~1(vi)
  • EP3599215B1 patent drawingFigure 2~3(b)
  • EP3599215B1 patent drawingFigure 4~5(b)

AI summary

Fork carriage (00, 300, 400) for a truck mounted forklift, the fork carriage comprising an upright rear section (201) for mounting onto the lifting assembly of the forklift, an upright forward section (203), shorter than the upright rear section, for reception of tines (205) and a pantograph linkage (207, 307, 407) connecting the upright rear section and upright forward sections together. The pantograph linkage comprises a first and second linkage arm (209) however the second linkage arm (211) is shorter than the first linkage arm and does not extend all the way forward to the upright forward section. Instead, there is provided a third linkage arm (223) with a hinge joint (229) along its length, the third linkage arm being connected at various positions along its length to each of the first linkage arm, the second linkage arm and the upright forward section. In this way, the pantograph linkage can achieve the same reach with a lower upright forward section and access to top far side loads is facilitated.