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Cranes and Slings

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Cranes and Slings Major Causes of Crane Accidents Contact with power lines Overturns Falls Mechanical failures * * * OVERTURNING ACCIDENTS Basically, overloading is ... – PowerPoint PPT presentation

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Title: Cranes and Slings


1
Cranes and Slings
  • Major Causes of Crane Accidents
  • Contact with power lines
  • Overturns
  • Falls
  • Mechanical failures

2
Crane Hazards
  • An unstable load, lack of communication, lack of
    training, and inadequate maintenance or
    inspection are major contributors to crane
    accidents.
  • Operators or others working in the area can be
    victims to struck by" and "caught in" injuries.
  • Contact with power lines causes many accidents.

3
Crane Hazards
  • Improper loading
  • Excessive speeds
  • No hand signals
  • Inadequate inspection and maintenance
  • Unguarded parts
  • Unguarded swing radius
  • Working too close to power lines
  • Improper exhaust system
  • Shattered windows
  • No steps/guardrails walkways
  • No boom angle indicator
  • Not using outriggers

4
Crane Parts
5
Rated Capacities
  • Make sure the crane operator can see the
  • Rated Load Capacities
  • Operating Speeds
  • Special Hazard Warning or Instruction
  • APPLICABLE OSHA STANDARD
  • 1926.1501 (a)(2) Rated load capacities, and
    recommended operating speeds, special hazard
    warnings, or instruction, shall be conspicuously
    posted on all equipment. Instructions or warnings
    shall be visible to the operator while he is at
    his control station.

6
Competent Person
  • The competent person must inspect all machinery
    and equipment prior to each use, and during use,
    to make sure it is in safe operating condition.
  • If it needs fixing, take it out of service and
    dont use it until it is fixed

7
Know the Weight of the Load
  • Refer to shipping ticket or other documentation
  • Ensure lift calculations are correct
  • Ensure load is within load chart rating for boom
    length and load radius of crane
  • Crane is rated by the maximum weight it will lift
    at a minimum radius and minimum boom length the
    further from its centerpoint, the less it will
    lift

8
Load Limiting Factors
  • Not level
  • Wind
  • Side loads
  • On its wheels
  • Lifting over the side
  • Use of extensions, jibs and other attachments
  • Limits of wire rope, slings and lifting devices

9
Load Example 30 ton crane
  • Will lift 60,000 pounds at 10 feet from the
    center pin of the crane
  • Based on level surface, no wind, and outriggers
    fully extended
  • At 25 feet from the center pin with an 80 foot
    boom, the capacity is only 14,950 pounds
  • At 74 feet from the center pin, the capacity is
    only 4,800 pounds

10
Wire Rope Slings
11
Alloy Steel Chains
Adapts to shape of the load Can damage by sudden
shocks Best choice for hoisting very hot
materials Must have an affixed tag stating size,
grade, rated capacity, and sling manufacturer
12
Chain Wear
When a chain shows excessive wear, or is cracked
or pitted, remove it from service Non-alloy
repair links can not be used
13
Wire Rope Slings
  • Used to hoist materials
  • Selection considerations
  • strength
  • ability to bend without cracking
  • ability to withstand abrasive wear
  • ability to withstand abuse

Wire
Core
Center
Strand
Wire rope
14
  • Damaged wire rope

Crushed Rope
Broken Strands
Damaged wire rope must be taken out of service
15
Protruding Ends
Cover or blunt protruding ends of strands
16
Wire Rope Clips
When using U-bolt wire rope clips to form eyes,
ensure the "U" section is in contact with the
dead end of the rope
Dead End
This is the correct method
17
Wire Rope Slings Remove From Service
If these happen, remove the wire rope sling from
service
Kinking
Bird Caging
Crushing
18
Synthetic Web SlingMarkings
  • Mark or code to show
  • Name or trademark of manufacturer
  • Rated capacities for the type of hitch
  • Type of material

19
Synthetic Web SlingStitching
Stitching
  • Stitching is the only method allowed to attach
    end fittings to webbing, or to form eyes

20
Synthetic Web Slings -Remove from Service
  • Remove from service if any of these are present
  • Acid or caustic burns
  • Melting or charring of any part
  • Snags, punctures, tears or cuts
  • Broken or worn stitches
  • Distortion of fittings

Heat Damage
21
Sling Tables
22
Sling Stress Example
  • From the table, a single branch with a 90 degree
    loading is rated at 3,250 lbs.
  • If there is a safety factor of 4, the chain could
    lift
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