Spreader Bar Connection Angles and Impact Faces

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Solution Overview

Problem

Spreader bars used in lifting dragline buckets are prone to damage when dropped, and the increasing size of buckets puts greater loads on these bars, leading to significant downtime and production losses due to frequent failures.

Innovation Solution

The design of spreader bars with strategically positioned connection points for hoist chains, angled to create a larger enclosed angle with the longitudinal axis, and end portions with flat lower faces to distribute impact loads, allowing for a lighter construction that engages the bucket's upper edges upon falling, thereby reducing damage and accommodating increased loads without weight increase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If spreader bar length is increased to accommodate larger bucket widths, then the spreader bar can handle larger buckets, but the spreader bar weight increases proportionately

Engineering Contradiction:

Improvebucket size accommodationVSAvoidspreader bar weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The spreader bar is divided into multiple segments: end portions with connection points, intermediate portions connecting them, and flat lower faces at strategic locations. This segmentation allows each part to be optimized independently for strength and weight, enabling the bar to handle larger buckets without proportionally increasing overall weight.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the spreader bar have different structural properties - end portions have connection points for chain attachment, intermediate portions have specific geometries for load distribution, and flat lower faces provide impact surfaces. This local differentiation allows the structure to be as light as possible while maintaining necessary strength where required.

Inventive Principle:

Principle #3Local quality

2Strength

If spreader bar connection points are positioned to create larger enclosed angles with the longitudinal axis, then the structural efficiency is improved, but the connection point spacing requires precise control

Engineering Contradiction:

Improvestructural efficiencyVSAvoidconnection point positioning

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The invention specifies that connection points be positioned to create enclosed angles with the longitudinal axis within the range of 45 to 90 degrees. This parameter specification optimizes the structural efficiency of the spreader bar while providing a practical design guideline that balances strength requirements with manufacturing feasibility.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If spreader bar is made lighter to reduce downtime and production losses, then the productivity improves, but the spreader bar may be more susceptible to damage when dropped

Engineering Contradiction:

Improvedowntime reductionVSAvoiddamage resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Flat lower faces are provided on the spreader bar at locations where impact with the bucket upper edge is most likely to occur. These flat surfaces act as predetermined impact zones that distribute drop forces across a larger area, protecting the lighter bar structure from concentrated impact damage and reducing the risk of failure.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The invention converts the harmful impact of drops onto the bucket edge into a beneficial force distribution mechanism. By designing flat lower faces at strategic locations, the harmful concentrated impact force is transformed into a distributed load across the flat surface, allowing the lighter spreader bar to withstand drops without proportional increases in weight.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS10689827B2Spreader bars and components therefor

Publication Date: 2020.06.23 2MT MINING PROD

AI summary

A spreader bar including two spaced apart opposite end portions, each end portion having a first connection point for connecting a lower hoist chain thereto and a second connection point for connecting an upper hoist chain thereto, said second connection point being spaced from said first connection point towards the opposite end portion by a first predetermined distance, said predetermined distance being selected such that in use an upper hoist chain connected thereto makes a smaller angle with the longitudinal axis of the spreader bar than would an upper hoist chain connected to the first connection point.