Iowa Case Report: 05IA002 |
Report Date: August 29, 2006 |
Summary
During the winter of 2005, an 81-
year-old farmer died while
pneumatically conveying corn
from a parked auger wagon into
an area of his machinery storage
shed. He was standing in the corn
near the front of the single-axle
grain cart, which had been
unhitched from the tractor. The
PTO-driven grain vacuum was
positioned in the doorway with the
tractor connected to it, to provide
power take-off (PTO) power, at an
angle to it outside the doorway
(Photo 1). When a sufficient
amount of corn had been
vacuumed from the front of the
wagon, the weight of corn
remaining in the rear of the
wagon caused the cart to tip rearward. The farmer was catapulted into the air and landed on the
concrete machine shed floor beside the tractor. He suffered a fractured skull and was rushed by
ambulance to a regional medical center where he died the next day.
|
Photo 1 - Grain cart tipped onto its rear beside tractor used to power the portable
grain vacuum that conveyed corn into the machine shed. |
RECOMMENDATIONS based on our investigation are as follows:
- Auger wagons that can tip rearward when unloaded unevenly should remain connected to the
tractor while they are being unloaded.
- Auger wagons, parked unhitched from the tractor, should be unloaded through a bottom opening
(when available) into a hopper from which the grain can further be conveyed.
- Auger wagons without a bottom opening, parked unhitched from the tractor, should be securely
blocked or anchored to keep them from tipping rearward or have the rear half of the wagon's
contents unloaded first.
Introduction
Early in the winter of 2005 an elderly Iowa farmer was killed while transferring grain from a grain cart
into a machine shed on his farm. The Iowa FACE program was alerted to this incident several
months after it happened during a routine review of shared data from collaborating sources. An
investigation was initiated at that time. Information was gathered from the State Medical Examiner's
Office, the County Sheriff, and from local newspapers.
Investigation
The farmer was moving corn into a corn storage area in his machine shed using a grain vacuum,
with 5 inch (127 mm) diameter ducting, that was powered by the tractor's PTO. The grain cart had a
capacity over 356 bushels (12.5 m3), or nearly 20,000 pounds (9,072 kg) of corn dry enough for
storage at 56 pounds per bushel (780 kg/m3) and 15.5% moisture content. The grain vacuum used
was capable of conveying 3500 bu/hr (125 m3/hr) when operating at capacity or about one bushel
per second (2 m3/minute). Operating at rated capacity such a pneumatic conveyor could empty a full
cart of the size in this incident in about six minutes.
The grain cart was moved into position and unhitched from the tractor. There was significant weight
on the tongue of the cart when it was disconnected so that its tongue jack needed to be lowered to
enable unhitching, which also kept the grain cart hitch from dropping to the ground. The access
ladder to this grain cart is over the hitch frame at the front of the grain box (Photo 2). The farmer
climbed the ladder and stepped into the grain cart carrying the intake nozzle and dragging the hose
of the grain vacuum with him. While he was suctioning grain from the front of the cart, at some point
in time the weight of grain ahead of the rear axle was reduced such that the remaining grain behind
the rear axle of the cart was enough to cause the cart to tip rear-ward.
|
Photo 2 - Overview showing the tractor, grain vacuum, and the grain cart tipped rearward. Note the ladder on the front of the cart
and the down position (for parking) of the jack attached to the hitch frame. |
The farmer was pitched from the front of the cart
when it rotated around the cart's axle and stopped
suddenly as the rear of the cart hit the ground. A
wooden brace at the front of the cart was broken,
indicating the magnitude of force that propelled the
farmer from his original position ahead of the brace.
The farmer flew through the air and landed on the
concrete pad near the tractor that was powering the
grain vacuum. He suffered multiple head injuries
including a fractured skull and was rushed by
ambulance to a regional medical center where he
died the next day.
|
Photo 3 - Wagon in rear tip position showing brace
broken when farmer was pitched from cart during the tip. |
Back to Top
Cause of Death
The cause of death taken from the Medical
Examiner's report was described as a "closed head
injury". No autopsy was performed.
Recommendations/Discussion
Recommendation #1 Auger wagons that can tip
rearward when unloaded unevenly should remain
connected to the tractor while they are being
unloaded.
Discussion: A grain cart hitch that remains connected to the tractor's drawbar cannot move and
therefore keeps the cart hitch from rotating upward and around the wagon axle when an imbalanced
load in the cart occurs that would otherwise cause an unhitched wagon to tip rearward. The tractor's
drawbar is captured inside the U-shaped end of the cart's hitch and pinned to it. Or, with other
hitching arrangements, the end of the cart's hitch can be captured inside the U-shaped end of the
tractor's drawbar and is pinned to it.
Recommendation #2 Auger wagons, parked unhitched from the tractor, should be unloaded
through a bottom opening (when available) into a hopper from which the grain can further be
conveyed.
Discussion: Lowering the cart's hitch to the ground results in a favorable change in geometry,
effectively moving the loaded cart's center of gravity further forward of the axle and making it more
difficult for the cart to tip rearward. Auger wagons often have an opening near the center of the
machine at the base of the auger through which grain can flow by gravity. When the contents of a
parked cart can be emptied by gravity out such an opening it minimizes the potential for the cart to
be unloaded unevenly and tip over. It also eliminates the need for the farmer to climb the ladder,
dragging the cumbersome grain vacuum nozzle and hose, and thereby eliminates the risk of falling
from the ladder by allowing the task to be performed at ground level.
Recommendation #3 Auger wagons without a bottom opening, parked unhitched from the tractor,
should be securely blocked or anchored to keep them from tipping rearward or have the rear half of
the wagon's contents unloaded first.
Discussion: If the parked and unhitched cart has no gravity flow opening at the base of the auger in
the middle of the cart, then unloading a single-axle cart from the top such as with a grain vacuum
should be done with special caution. The hitch should be securely anchored to the ground or the
rear of the cart blocked to prevent tipping to the rear. The grain vacuum's intake nozzle should be
placed out of the grain near the center of the cart. After climbing the ladder and moving into position
above the grain in the middle of the cart, the intake nozzle should be worked rearward from the
center of the cart to remove the grain in the rear of the cart first. This keeps a downward load on the
hitch point of the cart.
Iowa FACE Program
Fatality Assessment and Control Evaluation, FACE, is a program of the National Institute for
Occupational Safety and Health (NIOSH), which is part of the Centers for Disease Control and
Prevention of the U.S. Department of Health and Human Services. Nationally, the FACE program
identifies traumatic deaths at work, conducts in-depth studies of select work deaths, makes
recommendations for prevention, and publishes reports and alerts. The goal is to prevent
occupational fatalities across the nation.
The NIOSH head office in Morgantown, West Virginia, carries out an intramural FACE case
surveillance and evaluation program and also funds state-based programs in several cooperating
states. In Iowa, The University of Iowa through its Injury Prevention Research Center works in
conjunction with the Iowa Department of Public Health and its Office of the State Medical Examiner
to conduct the Iowa FACE program.
Nationally, NIOSH combines its internal information with that from cooperating states to provide
information in a variety of forms which is disseminated widely among the industries involved.
NIOSH publications are available on the web at http://www.cdc.gov/NIOSH/FACE/ and from the
NIOSH Distribution Center (1-800-35NIOSH).
Iowa FACE also publishes its case studies, issues precautionary messages, and prepares articles
for trade and professional publication. In addition to postings on the national NIOSH website, this
information is posted on the Iowa FACE site, http://www.public-health.uiowa.edu/FACE/. Copies of
FACE case studies and other publications are available by contacting Iowa FACE, too.
The Iowa FACE team consists of the following specialists from the University of Iowa: Craig
Zwerling, MD, PhD, MPH, Principal Investigator; John Lundell, MA, Co-Investigator; Murray
Madsen, MBA, Chief Trauma Investigator; and Co-Investigator/specialists Risto Rautiainen, PhD,
and Wayne Sanderson, PhD, CIH. Additional expertise from the Iowa Department of Public Health
includes Rita Gergely, Principal Investigator, and John Kraemer, PA, from the Office of the State
Medical Examiner.
To contact Iowa
State FACE program personnel regarding State-based FACE reports, please
use information listed on the Contact Sheet on the NIOSH FACE web site
Please contact In-house
FACE program personnel regarding In-house FACE reports and to gain
assistance when State-FACE program personnel cannot be reached.
|