Presentation on theme: "A NEW STICK-HARVESTED BURLEY TRANSPORT AND HOUSING SYSTEM 2012 Tobacco Workers Conference John Wilhoit Dave Ash George Duncan Department of Biosystems."— Presentation transcript:
A NEW STICK-HARVESTED BURLEY TRANSPORT AND HOUSING SYSTEM 2012 Tobacco Workers Conference John Wilhoit Dave Ash George Duncan Department of Biosystems & 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) Front-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 rails. 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
Front-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 sections. 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. Front-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 $10/hr
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 tractor. 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 (continued) 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 rqils 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.
ACKNOWLEDGEMENTS 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 project: Chance Corum Joey Jackson Will Pomeroy Travis Maupum Ben Herbener Rafael Nascimento