Basic Rigging And Wire Rope

Transcription

1 Basic Rigging And Wire Rope Presented By Master Builders of Iowa Basic Rigging and Wire Rope Topics Four Commandments of Rigging Sling Angles Types Of Hitches Types Of Slings Types Of Rigging Devices OSHA Rigging Regulations Wire Rope Four Commandments of Rigging 1 Know Thy Weight 2 Know Thy Capacity 3 Retain Thy Load 4 Control Thy Load 1

2 Sling Angle: Position Of Sling Relative To Horizontal Tension In Sling Increases As Angle To Horizontal Decrease Note Changes From Left To Right Sling Tension Doubles, Weight Remains The Same Good Practice To Keep Sling Angle Above 45 Degrees (Good) 60 Degrees (Best) Avoid Going Below 30 Degrees Types Of Hitches Straight Pull Or Vertical Choker Basket 2

3 Straight Pull (or vertical) Simplest Low Load Retention & Control Choker Hitch Highest Load Retention And Control Weaker Than Straight Pull Caution: Do Not Use As A Single Hitch For Loose Material To Determine Strength Reduction: D/d Ratio D = Diameter of Bend d = Diameter of Sling Applies To Any Hitch 3

4 Strength Of Choker = 75% of Straight Pull If: Sharp Corners Protected Sling Angles Not Less Than 45 Pounding Down the eye Double Wrap Choker Makes 360 Deg Contact, Squeezes Load High Retention Basket Hitch Conditions For Maximum Capacity Retention Varies With Load Low Control Caution This Hitch Is The Biggest Cause For Cranes Loosing Their Loads Caution Most Basket Hitches Do Not Meet The Spec. For The Full Basket Capacity Because Of Sling Angle or D/d. 4

5 Avoid Excess Spread Best Practice Keep Sling Angle Above 60 Degrees 60 Degrees or More Double Wrap Basket Hitch Makes 360 Degree Contact, Squeezes Legs Need Adjustment During Take Up High Load Retention Higher Control Than With Basket Bridles Combinations Of Hitches Sling Angle Factor Usually A Concern Problems With Load Share 5

6 Wire Rope Slings Most Common Economic, Lightweight, Flexible, Durable Damage Easily Detectable Tags Not Required But Good Idea Eyes Thimbles Wire Rope Slings (continued) OSHA Requirements Not Allowed For Slings, Bridles, And Bull Wires on Construction Projects Wire Rope Slings (continued) Remove From Service If: 10 Broken Wires In 1 Lay 5 Broken Wires In 1 Strand 1 Lay Severe Abrasion Distorted Rope Structure End Attachments Damaged Or Worn 1/3 Wear of Outside Wire Heat Damage 6

7 Synthetic Web Slings Easy To Use, Lightest, Less Likely To Damage Load Easily Damaged Use Special Fittings Tags Required Safety Yarn Chain Slings Highly Resistant To Heat And Abrasion Prone To Weak Link Failure Must Use Proper Chain And Fittings Caution Use Only Chain Approved For Hoisting Chain Slings (continued) Be Carful Not To Bend Links 7

8 Chain slings (continued) Wear Reach Tables Measure a Known Number of Links When New and Compare With Future Lengths Check Tables For Minimum Chain slings (continued) Readable Tags Required Shackles Recommended Types: Screw Pin Bolt 8

9 Shackles (continued) Do Regular Inspections Shackles (continued) -No Welding or Cutting -No Bolts To Replace Plus Shackles (continued) -Proper Choking 9

10 Shackles (continued) - Avoid Eccentric Loads - De-rate Not Professional Shackles (continued) -Can Be Symmetrically Side Loaded Without Derating 120 Degree Maximum Shackle Size 10

11 Hooks -Proper Use And Inspection Very Important -Do Not Ignore Hooks (continued) -Proper Load -Number of Slings -Exception For Shake-Outs Hooks (continued) -Working Safety Latches -Exceptions Latch 11

12 Hooks (continued) -Inspect Regularly -Take Out of Service if: 10% Wear Saddle Open up 15% Twist 10 deg. Hooks (continued) -No Welding Or Cutting Never Wire Rope Clips -Most Common Use On Cranes Crosby Says Tail Is 6 Rope Diameters Except For Rotation Resistant Which Is 20 Rope Diameters. 12

13 Wire Rope Clips (continued) -OSHA Prohibited Use On Slings -Allowed Uses -ANSI Requirement Forged Forged Malleable Wire Rope Clips (continued) - Proper Direction Never Saddle A Dead Horse U bolt Saddle Dead End Wedge Socket Most Commons Method To Terminate Crane Rope Easy To Use Parts Must All Match In Size 13

14 Wedge Socket (continued) - Correct Rope Installation Yes No Eye Bolts - Must Have Load Rating - Loading Bolts Without - Shoulders - Loading Bolts With Shoulders Shouldered Eye Shoulderless Eye Bolts May Only Be Loaded In This Direction 90 Deg. Bolts May Be Loaded Between 45 and 90 Deg. 45 Deg. Spreader Beams -Two Uses Spreaders Equalizers Spreader Equalizer Unequalizer 14

15 Spreader Beams (continued) - Often Custom Fabricated - ANSI Considered As Load This Equalizer Becomes An Unequalizer If It Gets Out Of Level Cap. 22 Tons Rigging Equipment - Regular Inspection Required - Must Take Damaged Or Defective Out Of Service - Do Not Overload - Custom-Made Equipment Slings - Protect From Sharp Edges & Corners - Must Not Contain Kinks - Cannot Be Pulled From Under Load 15

16 Slings (continued) - Means of Shortening - No Wire Rope Clips To Form Eyes Slings (continued) - Web Sling Require Readable Tags - Wire Rope Slings Do Not Require Tags - Requirements For Removal From Service Chain Slings - Allowed If Proper Material - Require Readable Tags - Required Written Inspection Records 16

17 Wire Rope Important Piece Of Equipment Requires Proper Use, Lubrication And Inspection Types Of Wire Rope - Abbreviations Used - Abbreviations Give Information About: Strand Construction Lay Core Grade Strand Construction -PRF.. Preformed -NP.. Non-Preformed -S.. Seale -W.. Warrington -WS.. Warrington Seale -FW.. Filler Wire 17

18 Lay Types -RRL.. Right Regular Lay -LRL.. Left Regular Lay -RLL.. Right Lang Lay -LLL.. Left Lang Lay Core Types -FC.. Fiber Core -IWRC.. Independent Wire Rope Core -PPC. Polypropylene Rope Core -SC. Strand Core Common Rope Grades (wire) -MPS.. Mild Plow Steel -PS.. Plow Steel -IPS.. Improved Low Steel -XIP.. Extra Improved Plow Steel -XXIP. Extra Extra Improved Plow Steel 18

19 Interpreting Abbreviations -1 1/8-6x31, WS, RRL, EIPS, PRF, IWRC -1 6x25 FW, RLL, IPS, PRF, IWRC -Assumptions If Direction Omitted -If Preform Designation Omitted Rotation-Resistant Rope - Forbidden On Boom Hoist Systems Fiber Core Also - Manufacturer s Direction For Use Of Swivels 17x7 18x7 34x7 12x6 over 3x4 Rotation Resistant Rope (continued) - Difficult To Find Damage - Higher Safety Factors - Removal From Service 2 broken wires in 6 rope diameters or 4 broken wires in 30 rope diameters Core Failure Causing Reduction in Diameter 19

20 Lay - Three Meanings 1 Direction Of Strands Right Lay Left Lay Lay (continued) 2 Appearance Of Individual Wires Right Regular Lay Right Lang Lay Lay (continued) 3 Length Of Rope Lay Length 20

21 Caring For Wire Rope -Keep Clean -Keep Lubricated Brush Application Shown There Are Other Methods Available 21

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