Equipment Certification Towing Structures

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Equipment Certification- Towing Structures
JADE Engineers Inc.

• Presented By
• André Brisson, P. Eng., ing.
• CUFF 2009, Québec City

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JADE Engineers
JADE Engineers Inc.

• Structural engineering and certification
• Finite Element Analysis (FEA)
• Fall protection systems
• Performance testing
• 3D CADD using SolidWorksTM
• We service the utility, construction, industrial,
  and residential sectors.

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Why Engineering/Certification?
JADE Engineers Inc.

• Legislated requirement for many items
• Independent third party opinion/review
• Deferral of liability or responsibility
• Due diligence to meet Health and Safety Acts

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What Items Require Engineering/Certification?
JADE Engineers Inc.

• Stability testing of aerial devices
• CSA compliance of new or alien aerial devices/EWP
• Annual inspection of mobile cranes
• 10 year inspection of EWP and telescopic cranes
• Structural repairs to aerial devices, EWP, cranes
• All lifting devices for cranes, forklifts, etc.
• Jib and overhead cranes
• Towing structures (tow hook attachment to truck)

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Towing Structures
JADE Engineers Inc.

• Cannot purchase a kit
• Custom fabricated attachment connecting the
  trailer to the truck frame via trailer hitch.
• Towing structure strength requirements are
  legislated by provincial/territorial regulations
• Trailer couplings (tow hooks and eyes) are mass
  produced and meet requirements of SAE recommended
  practice papers.

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SAE Recommended Practices
JADE Engineers Inc.

• Society of Automotive Engineers
• Advance the state of technical and engineering
  sciences.
• J847 Trailer Tow Bar Eye and Pintle Hook
  Coupler Performance
• J849 Connection and Accessory Locations for
  Towing Multiple Trailers Trucks and Bus

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SAE J847 and J849
JADE Engineers Inc.

• Both state the support structures must
  withstand the indicated test loads without
  residual deformation of any components which will
  affect their intended performance.
• Residual deformation permanent deformation

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SAE J847 and J849
JADE Engineers Inc.
50,600 lb
22,000 lb
55,176 lb
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Ontario Regulation 618Specifications and
Standards For Trailer Couplings
JADE Engineers Inc.

• Trailer hitch shall,
• Be of sufficient strength to withstand a force
  equivalent to the gross weight of the trailer(s),
  without residual deformation to the trailer
  hitch.
• SAE J847 and J849 state the same

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Ontario Regulation 618Specifications and
Standards For Trailer Couplings
JADE Engineers Inc.

• The following items shall have sufficient
  strength equal to or greater than that of the
  trailer hitch.
• Attachment of hitch to towing structure
• Towing structure
• Attachment of towing structure to truck frame
• Be reinforced or braced to prevent truck frame
  distortion.

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Ontario Regulation 618Specifications and
Standards For Trailer Couplings
JADE Engineers Inc.

• Trailer shall be coupled to the frame or an
  extension of the frame of a truck with a safety
  connecting device.
• Safety connecting device anchor load path must be
  direct to the truck frame.

Chains, cables
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What do we design to? Regs? SAE?
JADE Engineers Inc.

• Regulations are minimum requirements that are
  enforced by regulatory bodies.
• SAE standards are not legislated
• Tow hooks and eyes state in their documents
• Use a mounting structure of sufficient strength
  to support the rated capacity of the tow hook in
  accordance with SAE J847 and SAE J849.

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How do you decide?
JADE Engineers Inc.

• Regulations do not give load values
• SAE has values 115 H and 50 V
• SAE is an industry accepted standard
• As an engineer, the load requirements of the SAE
  documents are reasonable and representative of
  trailer loads.

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Trailer Attachment Safety
JADE Engineers Inc.

• Tow hook location is critical for the safe
  operation of the trailer
• Height for level trailer
• Tow bar swing clearances (step bumpers)
• Safety chain locations (eyes)
• Hitch Offset

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Hitch Offset
JADE Engineers Inc.

• Hitch Offset
• Longitudinal distance from the towing vehicle
  rear axle to the articulation point of the hitch
  or fifth wheel used to tow the trailer.

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Hitch Offset Limit
JADE Engineers Inc.

• The Federal-Provincial-Territorial Memorandum of
  Understanding on Interprovincial Weights and
  Dimensions (MOU)
• All provinces/territories have adopted the MOU
  limits except for Ontario.
• Ontario is currently working to legislate the MOU

Max. 1.8 m (5.86 ft)
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Hitch Offset Effects
JADE Engineers Inc.

• Hitch offsets greater than 1.8 m will affect
• Trailer sway when changing lanes,
• Trailer tracking and control,
• Truck vehicle weight distribution
• This is an enforceable requirement that can deem
  it an illegal vehicle configuration
• Province/territory could impose a fine
• Impound vehicle
• Require a fix

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Summary
JADE Engineers Inc.

• Towing structures are regulated
• Use SAE J847 and J849 load test values
• Towing structures should be engineered
• Hitch offset is regulated for safe operation
• Hitch offset infraction is enforceable

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Questions?
JADE Engineers Inc.