Human factors for the design and
operation of mobile equipment
Alison Godwin, PhD Executive Member, Centre for Research in Occupational Safety and Health
Assistant Professor, School of Human Kinetics
Tammy Eger, PhD Director, Centre for Research in Occupational Safety and Health
Associate Professor, School of Human Kinetics
WSN Health of a Miner Symposium
November 12, 2014
Bulldozer: stiff shoulder, fatigue, LBP
Crane operator: back disorders, vibration
Earth moving: LBP, discomfort, spine
disorders
Forklift: stiff shoulder, LBP, fatigue
Power Shovel operator: stiff shoulder, LBP
Tractor operator: vibration and LBP
Zimmerman Profile of MSD’s
in heavy equipment operators
Longer employed Older equipment
The field of human factors is
concerned with the
interaction between
people and work systems,
in order to maximize
human well-being and system
performance.
Why human factors &
ergonomics?
What are some of the concerns
with heavy equipment operation?
Line-of-sight and visual field
Seating quality
Cabin space
Control layouts
Ingress and egress
Work scheduling
Poor LOS is a cause for concern
Loaders, haul trucks and other heavy equipment are often involved in
accidents due to poor LOS
Heavy equipment operators are at increased risk for back and neck
musculoskeletal disorders
Large Machines and Line-of-Sight
Pedestrian
The pedestrian is no longer visible
What DOESN’T an
operator see?
Pick-up Truck
Recent Coroner’s Inquests
(Ontario, Canada)
recommend renewed focus
on LOS and earth moving
equipment (2009, 2010)
Machine Components and LOS
Cab Design (posts & windows)
Light Posts/Brackets
Bucket size
Engine profile
Driving posture during
LHD operation has neck rotated more than 45⁰ for over 89% of the shift
Limits for awkward neck postures have been documented by only a few sources:
Swedish National Injury Criteria (Eklund et al. 1994)
• Neck should not be rotated >45deg for more than 50% of the shift. Suggested Neck Postures (Gellerstedt et al. 1999)
• Operators should not be required to rotate head <30deg. • Operators should not have to tilt head > 5deg upwards or >25deg downwards.
LHD Operator Posture & LOS
Seat adjustability Seat height
Seat angle
Seat swivel
Cabin space
Improve line of sight
Enhance mirrors or camera use
Reduce postural requirements
Posture Variables
8.26 7.71 6.25
19.4 17.714.9
42.638.7
31.1
0
10
20
30
40
50
0 20 45
Seat Rotation (degrees)
Po
stu
re C
rite
ria
(de
gre
es
)
Trunk Lateral Bend Trunk Rotation Neck Rotation
Seat rotation resulted in significantly less
trunk lateral bend, trunk rotation and neck
rotation.
0 degrees
45 degrees
Seat Rotation
666666666666666666666 Kittusamy Ergonomic Checklist for
Cab Design on Construction
Machinery
Seat adjustability factors
Armrest adjustability factors
Vibration overview
Dynamic armrest by
Michele Oliver
University of Guelph
* Pictures from Murphy and Oliver, 2011 **Patent pending
666666666666666666666 Kittusamy Ergonomic Checklist for
Cab Design on Construction
Machinery
Seat adjustability
Controls factors
Environment factors
Visibility factors
Ingress/Egress
Visibility factors
Cab Space ISO 3411:2007 Earth-moving machinery -- Physical dimensions of operators and minimum operator space envelope Provides the dimensions of operators of earth-moving machinery and specifies the minimum normal operating space envelope within the operator enclosures.
ISO 6682:1986 Earth-moving machinery -- Zones of comfort and reach for controls Defines zones of comfort and reach for controls derived from the overlapping reach capability of large and small operators in the seated position. Is intended as a guide for the design of the operator compartment controls for earth-moving machinery
Seat Adjustment
ISO 11112:1995 Earth-moving machinery -- Operator's seat -- Dimensions and requirements Specifies the dimensions, requirements and adjustment ranges for operator seats on earth-moving machinery. Additionally, it contains dimensions for armrests when fitted on these machines
Environmental: Cab
Temperature consistency
Temperature distribution
Loudness of alarm
Type of alarm (frequency, tone, etc)
Ventilation concern
ISO/CD 1996-2 Acoustics -- Description, measurement and assessment of environmental noise -- Part 2: Determination of environmental noise levels
http://www.volvoce.com/SiteCollectionDocuments/VCE/Documents%20North%20America/backhoe%20loaders/bl60b-bl70b%20product%20brochure.pdf
EMESRT Design Philosophies
DP – 1 Access and Working at Heights www.51933.activeboard.com
ISO for Controls and Displays
ISO 6011:2003 Earth-moving machinery - Visual display of machine operation Specifies the machine operation functional information to be presented by the visual displays of earth-moving machinery for a seated operator.
ISO 6405-1:2004 Earth-moving machinery -- Symbols for operator controls and other displays -- Part 1: Common symbols ISO 6405-2:1993 Earth-moving machinery -- Symbols for operator controls and other displays -- Part 2: Specific symbols for machines, equipment and accessories The symbols given apply to controls and displays specific to backhoe loaders, dozers, loaders, graders, scrapers, excavators and dumpers, and for controls and displays for stabilizers, outriggers, grapples, rippers and winches.
Controls &
Displays
Checklist Items to Consider
Protection against movements
Controls activate functions according to figures
Controls follow directional compatibility
Primary controls within the comfortable zone
Secondary controls within reach zone (no excessive movement)
Control adjustability desirable
Location of visual displays within 30⁰ cone of operator position
Legible displays in all lighting conditions
Final Thoughts
Although we have presented many of the challenges with heavy equipment design in isolation – the issues are often more complex and interrelated.
Reducing adverse health effects associated with mobile equipment operation (poor LOS, awkward postures; whole-body vibration exposure;controls/displays; ingress/egress) will require a multifaceted approach involving participation of workers, industry leaders, equipment manufacturers, and researchers.
Industry Partners Workplace Safety North Ontario Mining Industry Northern Ontario Steel Manufacturing Industry
Research Partners Dr. Paul-Emile Boileau, IRSST (Montreal, QC) Dr. James Dickey, University of Western Ontario Dr. Michele Oliver, University of Guelph Dr. Joan Stevenson, Queen’s University Graduate and undergraduate RA students
Acknowledgements
Funding Agencies
For more information contact: Tammy Eger, Ph.D. ([email protected])
&
Alison Godwin, Ph.D. ([email protected])
Centre for Research in Occupational Safety and Health
Laurentian University
Ramsey Lake Road, Sudbury, ON, Canada, P3E 2C6
Web: www.crosh.ca
Twitter: @crosh_crsst
CROSH Centre for Research in Occupational Safety and Health
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Heavy Mobile Equipment - Ergonomics and the Prevention ofMusculoskeletal Injuries. Linda Miller, EWI Works International Inc. and Claire Gariepy, EWI
Works International Inc.