Lift-Truck Mast Guide-Roll Wear Reduction

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Solution Overview

Problem

Conventional guide-rolls in lift-trucks experience uneven wear due to external forces and track irregularities, leading to reduced service life and increased maintenance costs.

Innovation Solution

A guide-roll arrangement featuring a roll pin with a recess containing a sliding element with concave and convex contact surfaces, allowing the sliding element to move freely in all directions and maintain constant pressure on the track bottom, regardless of angular displacement between mast segments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional guide-roll with a sliding block is used to guide movement between mast segments, then smooth axial movement is achieved, but uneven wear occurs due to external forces and track irregularities

Engineering Contradiction:

Improvesmooth axial movementVSAvoidservice life of sliding block

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The sliding block is designed to be movable relative to the guide-roll hub, allowing it to dynamically adjust its position and orientation in response to external forces and track irregularities. This dynamic capability enables the sliding block to maintain optimal contact with the track bottom while distributing wear more evenly across its surface area.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The guide-roll assembly is segmented into distinct functional components: the guide-roll hub, the sliding block, and the connecting mechanism. This segmentation allows the sliding block to independently respond to track conditions while the hub provides stable rotational guidance, separating the functions of rolling guidance and sliding support.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If the sliding block is fixed to the guide-roll hub, then structural simplicity is maintained, but uneven pressure and excessive wear result from track irregularities

Engineering Contradiction:

Improvestructure of guide-rollVSAvoidwear of sliding block

Core Design Contradiction:

Device complexityVSLoss of substance

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If the sliding block contacts the track bottom with constant pressure, then smooth movement is maintained, but wear increases due to continuous high-pressure contact

Engineering Contradiction:

Improvesmooth movementVSAvoidwear of sliding block

Core Design Contradiction:

Ease of operationVSLoss of substance

Solution Approach 1:

The sliding block can dynamically adjust its contact pressure with the track bottom based on actual operating conditions. When the lift-truck encounters track irregularities or external forces, the sliding block moves to maintain contact while distributing the load over a larger area, reducing peak pressures and associated wear.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The contact parameters between the sliding block and track bottom are made variable rather than fixed. The sliding block can change its position, orientation, and contact area in response to operating conditions, allowing the system to optimize the balance between maintaining smooth movement and reducing wear through parameter adaptation.

Inventive Principle:

Principle #35Parameter changes

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

This design significantly reduces wear on the sliding element, resulting in longer service life and lower operational costs for lift-trucks by ensuring consistent contact with the track bottom.

Implementation Method 1

the sliding surface 32 of the sliding element 30 is configured to slidable engage the bottom 115 of the track 114

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS10549971B2Guide-roll arrangement for guiding relative movement of mast segments of a lift-truck and a lift-truck comprising a guide-roll arrangement

Publication Date: 2020.02.04 TOYOTA MATERIAL HANDLING MFG SWEDEN

AI summary

A guide-roll arrangement for guiding movement of a second mast segment relative a first mast segment of a lift-truck, comprising a roll pin having opposing first and second ends, wherein the first end comprises a recess, and a roll supported on the roll pin; and a sliding element arranged in the recess, said sliding element comprising opposing contact and sliding surfaces, wherein a support piece is arranged in the recess and comprising a contact surface for supporting the sliding element, wherein the contact surface of the sliding element is supported on the contact surface of the support piece and wherein one of the contact surfaces of the support piece and the sliding element is concave and the other is convex.