Adjustable Wear Block for Mast Clearance and Pad Life

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Solution Overview

Problem

Conventional wear pad systems in lift trucks and stackers are difficult to access and adjust, leading to premature replacement and increased maintenance costs due to the challenge of maintaining the correct clearance between wear pads and mast channel walls, which can result in either excessive wear or binding during operations.

Innovation Solution

An adjustable wear block system with a circular housing and rotatable metal base allows for easy adjustment of the wear pad height, featuring a threaded base that can be secured with fasteners and locked in place, and an optional hydraulic system for precise clearance control, enabling the wear pad to maintain optimal distance from the mast channel wall without requiring frequent replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If wear pads are designed to wear down over time, then the wear pad material can be utilized fully, but the clearance between wear pad and channel wall becomes difficult to maintain at a constant level

Engineering Contradiction:
Improvewear pad material utilizationVSAvoidclearance maintenance
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The wear block incorporates an adjustable mechanism that allows the wear pad position to be dynamically adjusted as the pad wears down. The adjustable component enables operators to move the wear pad closer to the channel wall over time, maintaining optimal clearance throughout the pad's service life rather than being fixed at initial positioning.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system allows changing the positional parameter of the wear pad relative to the channel wall. By providing adjustment capability, the clearance distance parameter can be modified as the wear pad thickness decreases, ensuring consistent operational clearance despite material consumption.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If wear pads are positioned close to the channel wall, then sideways forces can be absorbed effectively, but binding or sticking can occur during lifting and lowering operations

Engineering Contradiction:
Improveforce absorption capabilityVSAvoidlifting operation smoothness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The adjustable wear block allows operators to dynamically position the wear pad at optimal distances from the channel wall. This enables tuning the system to achieve the right balance between force absorption (when closer) and smooth operation (when slightly farther), adapting to different operational conditions and wear stages.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If wear pads are positioned far from the channel wall, then clearance is maintained for proper lift operation, but excessive play and side-to-side movement occur

Engineering Contradiction:
Improvelift operation clearanceVSAvoidcarriage stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The adjustment mechanism enables dynamic optimization of the wear pad position, allowing operators to set the precise clearance needed for smooth lift operations while maintaining sufficient proximity to the channel wall to minimize excessive play and stabilize carriage movement during lifting and lowering.

Inventive Principle:
Principle #15Dynamics

4Reliability

If wear blocks are located between the mast and mast rails or between the mast and carriage, then sideways forces can be absorbed, but servicing or replacement of wear pads becomes extremely difficult and time consuming

Engineering Contradiction:
Improveforce absorption functionVSAvoidwear pad accessibility
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The wear block is designed as a separate, modular component that can be independently accessed and adjusted. The adjustable mechanism is positioned such that it can be serviced without removing the entire mast or carriage assembly, dividing the service task into manageable steps accessible through existing gaps or openings.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adjustment mechanism is designed to be user-friendly and accessible, allowing operators to perform maintenance and adjustments themselves without requiring specialized service center equipment or procedures. The mechanism can be adjusted through existing access points without disassembling major components.

Inventive Principle:
Principle #25Self-service

5Productivity

If conventional wear pads are used, then the system can operate, but frequent replacement is required due to difficulty in adjustment and maintenance

Engineering Contradiction:
Improveoperational continuityVSAvoidmaintenance time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The adjustable wear block extends the service life of each wear pad by enabling continuous positioning adjustment as the pad wears. This eliminates the need for premature replacement due to clearance issues, maximizing utilization of each pad's material and reducing maintenance frequency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The easy-adjustment mechanism allows operators to perform maintenance themselves in the field without returning to the dealer. This self-service capability significantly reduces downtime and maintenance costs by enabling on-site adjustment and extending pad life through proper positioning.

Inventive Principle:
Principle #25Self-service

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

The adjustable wear block system simplifies maintenance by allowing on-site adjustment of wear pad height, extending the life of the wear pads, reducing material waste, and lowering maintenance costs by enabling precise control of clearance, thus preventing damage to lift components and ensuring smooth operation.

Implementation Method 1

A threaded base (formed of metal or other rigid material) is arranged in the housing such that its position within the housing can be adjusted by rotating the metal base with respect to the housing

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4484357A1Adjustable wear block for mast systems
Publication Date: 2025.01.01 HYSTER YALE MATERIALS HANDLING INC
  • EP4484357A1 patent drawingFigure 1
  • EP4484357A1 patent drawingFigure 2
  • EP4484357A1 patent drawingFigure 3

AI summary

An adjustable wear block (400, 500, 700, 1000) for a mast system (200) can include a housing (402) and a wear pad (410, 510, 710, 1010) arranged on an adjustable base (404, 520, 720, 1020, 1022) within the wear block housing (402, 702). In one embodiment, the wear block (400, 500), wear pad (410, 510), and adjustable base (404, 520) all have a circular cross-section. Threading (405) on the outside of the base (404) can match threading (403) on an inner wall of the housing (402). As the base (404) is rotated within the housing (402), the position of the base (404) and the attached wear pad (410) can be adjusted with respect to the housing (402). A hole can be provided through a channel (220) or mast (210) wall to permit an adjustment tool (440) to be used to adjust the position of the base (404) with respect to the housing (402) after the wear block (400) is secured to the carriage (220) or mast (210). In alternate embodiments, a hydraulic piston (520, 720, 1020, 1022) can drive the position of the wear pad (410, 510, 710, 1010) with respect to the wear block housing (402, 702).