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15 Νοε 2013 (πριν από 4 χρόνια και 5 μήνες)

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2012 Tobacco Workers Conference

John Wilhoit

Dave Ash

George Duncan

Department of

& Agricultural Engineering

University of Kentucky

Key Features of System

Sticks of tobacco are picked up in the field and loaded onto wooden rails
held in place on a rail wagon.

Rails are marked for space to skip sticks to leave room for forks to slide
under a load and lift the wooden rails loaded with tobacco.

Three rails holding approximately 50 sticks of tobacco are lifted at a time
with a large set of forks on a tractor front
end loader.

The load is transported by the tractor and set in place on portable wooden
field structures.

A key to this concept was whether the unsecured rails of tobacco could be
transported on the forks effectively.

A second main key was whether the manipulations required with the forks
for loading and unloading could be done efficiently.

The final main key to the concept was having a simple, economical portable
field structure so that transport distances could be kept to a minimum.

Requires sufficiently large tractor and front
end loader to handle the load
(approximately 100 hp)

end Loader with Forks on JD 2755 Tractor

Importance of Portable Field Structure

Field structure can be set up much closer to the tobacco
being harvested.

Close proximity to tobacco minimizes transport distance, and
therefore maximizes labor savings associated with handling
and transporting tobacco in a large unit.

Encourages rotation of tobacco fields because maintaining
close proximity with fixed field structure would, in essence,
require three times the field structure capacity as the
amount of tobacco produced.

Structures can be moved into storage during the off season,
prolonging their life and leaving fields clear.

“Sawhorse” Portable Field Structures

16 ft beam made from two 2 in. x 8 in. boards sandwiched together.

Legs made from 2 in. x 8 in. boards to give a beam height of about 6 ft.

Legs pivot on pins to “wedge” into stable position in one direction, have
wide stance (29 in.) for stability in other direction.

Lower piece across legs provides structural stability, keeps legs from sinking
into soft ground.

Sawhorses are placed 13 ft apart, for setting down 14 ft long wooden

Each pair of sawhorses supports two sets of three wooden rails loaded with
tobacco, for a total of approximately 100 sticks.

Risers in center of sawhorses hold 2x4’s to peak the plastic, shed water

After tobacco rails are removed, sawhorses can be loaded up using forks,
will nest for compact storage.

Rails are spaced 40” on centers.

Note workers setting a fresh set of rails in place.

Rail Wagon with Cups to Hold Wooden Rails in Place

Red spacers show where to skip a stick for forks.

Space also left at the ends of the rails to help facilitate unloading at sawhorses.

Note supply of rails carried on rail wagon, for restocking.

Workers Loading Rail Wagon

Forks are 9’ long, spaced 6’ apart.

Forks on Front
End Loader Lifting Load of Tobacco

Note tips of forks protruding past rail.

Forks on Front
End Loader Lifting Load of Tobacco

Transport speeds averaged 3.7 mph loaded and 5.7 mph empty in trial harvesting
approximately 1 acre.

Route was about 2/3 paved, so slower speeds are expected for all in
field travel.

Tractor in Transport with a Load

end loader has to lift load above risers in the middle of the sawhorses to load both loads in a
section from the same side

Ends of wooden rails that overhang the sawhorse beams have to be offset for unloading subsequent

Loading in field averaged 71 seconds and unloading at structures averaged 210 seconds in trials.

Unloading Tobacco onto Sawhorse Structures

Risers in center of sawhorses are notched for 2x4’s on end to be set in place after
the structures have been filled with tobacco.

Forks on front
end loader facilitate placing the 2x4’s and covering the structures
with plastic.

Boards Set in Place on Risers after Structures Filled

Sawhorse field structures are covered with plastic the same as other field structures.

Requires wide plastic (25’) to cover the 16’ long sawhorses.

Structures seem to be sufficiently stable due to tobacco load and wide stance. Structures have been
stable in high winds in two seasons of trials.. However, keeping plastic intact in high winds is always
a challenge, as with any field structure.

Filed Structures Covered with Plastic Following Harvest

Legs can be offset so that sawhorses “nest” for more compact transport and storage.

Forks and front
end loader facilitate quick set
up and take
down of the structures

as well as transport.

end Loader with Load of Sawhorses

Effect of Travel Time on Potential Labor Savings

At 50 sticks per load, approximately 24 loads required per acre.

With an 8 minute turn
around time per load (0.13 hr), 3.2 hr required per acre.

Important to keep distance to a minimum, under 300 ft.

Cost Considerations for System

$1500 (materials only) estimated for rail wagon, $500 (materials
only) estimated for forks; should be good for 20 ac/year

$675/ac (materials only) for sawhorses; comparable/little less than,
other outside field structure costs

$1000/ac for rails (96/acre); added to sawhorse cost, makes it
somewhat higher than other field structure, but considerably less
than new barn construction.

Labor savings potential approximately 7 hr/ac compared to field
structure housing

Labor savings potential up to 20 hr/ac or more compared to
traditional barn housing

Potential savings of $70
$200/acre in labor costs at

Summary and Conclusions from 2011 Harvesting Trials

Combined loading and unloading time averaged 281 sec (4.7 min) for 10 timed cycles. In actual
production, occasional unloading difficulties are likely to increase the average cycle times, but experience
gained with the system should counter
balance that increase. So, 5 min loading/unloading cycle times are
considered realistic.

Maneuvering and travel with a load of tobacco blocking the view was somewhat challenging but not really
very difficult. We averaged travel speeds of 3.7 mph loaded and 5.7 mph unloaded in 10 timed cycles
over a mixed in
field and paved route. If the route is completely in
field, average speeds of at least 2
mph loaded and 4 mph unloaded should be possible.

Tobacco loads were surprisingly stable during travel . Sticks did fall off occasionally, and the wooden rails
shifted slightly during transport on a few occasions, but this did not seem to be a problem.

The tobacco load did cause the tractor to be light in back. Weights should be added to the rear of the

The design of the portable wooden sawhorses is a critical issue. We had some failures of an earlier version
of the sawhorses with lighter legs and smaller diameter bolts for pinning the legs on the beams. A second,
heavier version performed satisfactorily, but we are still working to refine the design. Accurate force
analysis of the sawhorse is surprisingly difficult!

Summary and Conclusions from 2011 Harvesting Trials


Determining actual labor savings achieved with this system will require extensive field trials. While the
calculations of the labor requirements for the actual loading/unloading with this system (and hence the
potential labor savings compared to standard housing methods) should hold, the overall labor savings
potential will depend on a number of factors related to logistics and operations in standard operation.

Labor requirements for loading operations in the field will almost certainly be higher than standard
harvesting operations because the workers have to spread the tobacco on the stick as they hang.
Extensive field trials are needed to determine how much higher.

Handling the wooden rails, both for loading a supply to be carried on the rail wagon and for setting
the three rails in place for each load, requires considerable additional labor. We have already made
modifications to the rail wagon to facilitate loading 12

at once on the rail wagon using the
forks and to make it easier to set the individual rails in place in the cups on top of the rail wagon.

Efficient systems for handling and transporting large numbers of rails and sawhorses will have to be
developed through experience in actual production.

Even without using forks to handle and transport the loads, the portable sawhorses and wooden rails could
be an efficient option for curing capacity expansion.


2012 Tobacco Workers Conference

Funding support for this project was provided by Altria Client Services as part
of a “University Challenge” grant for developing low
cost harvest
mechanization strategies to benefit smaller burley tobacco growers.

Students contributing
to this

Chance Corum

Joey Jackson

Will Pomeroy


Ben Herbener

Rafael Nascimento