«Ohio University Mechanical Engineering Team Captain Plant It June 2010 1.0 INTRODUCTION Appalachia is a 205,000-square-mile region that follows the ...»
Design Summary Report
Team Captain Plant It
Appalachia is a 205,000-square-mile region that follows the spine of the Appalachian
Mountains from southern New York to northern Mississippi, which includes 33 counties in
southeastern Ohio. The region’s economy is highly dependent on heavy industry, agriculture
and mining. According to a recent Appalachian Region Income Report; per capita personal income was 20% lower than in the nation as a whole in 2007 (1). In Southeastern Ohio, per capita market income in 2002 was $18,037, or 26.3% lower than that of the total state, and 31.7% lower than the national average. In this region, 42% of the population is rural and the sustaining economy is agriculture. Over 50% of the southeastern Ohio counties are ranked “at risk” or “distressed” according to the Appalachian Region Commission’s (ARC) county economic status report in 2010(See Figure 1.1 (2)).
In order to solve the economic problems in the Appalachian region, the ARC conducted a series of studies. Results indicated that the farmer’s share in the traditional market is only 22 cents to every dollar of the total price of the product, and the rest of the shares go to marketing, processing, distribution and retailing, in which no value is added (2). In response to the Figure 1.1: Map of Distressed Counties in Appalachia (2).
distressing situation in the Ohio Appalachian region, The Appalachian Staple Food Collaborative (ASFC) was founded with the goal of increasing farmer’s income, and pushing the idea of, and catering to, the “locavore” movement in the southeastern Ohio region. “Locavore” is the movement to eat healthy foods that are both grown and produced in close proximity to where they are consumed. It is a method to build a sustainable local food system that will make farmers become an integral part of the complete food value chain rather than isolated in a production-only role on the food marketing cycle (3).
The ASFC is lead by Michelle Ajamian and Brandon Jaeger who have introduced staple foods T such as millet, spelt, amaranth, meal corn, bean and buckwheat back into the Athens food market. They are working with local farmers and the local community gardens, which all have relatively small plots of land to plant on. The equipment commercially available in the United States currently caters to large farming cooperatives. The ASFC’s goal is to bring a cost effective processing solution to small scale farming cooperatives that cannot afford to hire in large combines.
The Shagbark Seed & Mill Company, a subsidiary to AFSC, was created to solve the T equipment issues the region is suffering from. Ohio University’s Department of Mechanical Engineering Senior Design offered two teams to begin the task in solving this engineering problem. These two teams were tasked in completing phase one of this project; the initial prototype design and construction of the thresher and de-huller. Phase two, the validation of designs, will be continued as graduate work by Joseph Schultheis beginning in the summer of
2010. Development of the cleaning mechanisms for both the thresher and the de-huller may be continued by another senior design group for the 2010-2011 school year under the guidance of Mr. Schultheis.
2.0 CUSTOMER NEED STATEMENT
The need is for an appropriately sized machine to thresh and clean multiple grains such as:
T spelt, amaranth, buckwheat, millet, beans and corn crops. Some of these crops will then need to be de-hulled and re-cleaned. These crops are comprised of primarily buckwheat and spelt. Two teams worked together on the development of this equipment. Team Captain Plant It had the responsibility for the threshing and initial cleaning process and the other team, the Plainsmen, dealt with the de-hulling and final cleaning phases. This machine had to be portable and user friendly in order to be used by multiple persons at multiple locations in the community.
Challenges were expected to arise due to the integration of the four phases and the management of two teams. This machine must be flexible enough to be easily converted from doing all four operations to doing the first two (threshing and cleaning). It must also be easily convertible between the different crops. The challenge for the teams is to produce a machine that is practical, cost effective and have a phase one prototype completed by the end of spring quarter of 2010.
5.0 DEVELOPMENT The development process began with the concept design, including picture designs and ideas, and then moved on to CAD parts and then subassemblies. Once there was 90 to 95 percent of the assembly on file the team ordered the angle iron, sheet metal, and necessary nuts, bolts, washers, and lock washers. The frame was the first part to be assembled. The shaft was then ordered and cut to the appropriate length and diameters. Bearings were then chosen for the RPM range according to the required specifications of the customer. A 3.5 HP Briggs & Straton 4 cycle motor was purchased and an addition to the frame was needed for a desirable spot for it.
The next step was to start assembling the threshing drum. This required a redesign of the wheels connecting the rasp bars to the shaft. While the wheels were being manufactured the sheet metal needed to be replaced because it was too thick to bend in the press. Once 16 gauge was acquired the output was then made using the press and assembled with rivets. Next, the cover and input, made of the same 16 gauge sheet metal, were cut using the press brake and then bent to size.
During this time the concave was outsourced to Logan Bending. The drum was then fully assembled using shear pins to transfer power from the shaft to the drum and the rasp bars were bolted to the wheels. Special steel supports were made to be welded from the bottom of the concave to a 2” wide piece of U-channel. This assembly was then bolted to the top of a scissor jack that was then all leveled out and finally bolted to the frame. Once the drum/concave assembly was set, the input, output, and cover were all mounted. Two piano hinges were used to connect the cover to the output, making the drum and the engine easily accessible. A 3/8” slot was cut into a 2 foot long square metal tube and was then mounted to the frame so the idler pulley can be adjusted if necessary. The belt was then made taunt and a shield was made out of sheet metal to cover the transmission. The feet were welded onto the bottom of all the legs.
Pieces of rubber were put between the motor and the frame, the scissor-jack and the frame, and the feet and the mounting spots on the trailer. It was then painted black and a clear coat of paint was put on top. The finishing touch was having our customers initials (ASFC) painted on the cover.
Figure 6.2: Threshed millet is laid out in the following Table 8.1. This is an accurate estimate of the final cost of the thresher including manufacturing time and overhead. This meets our specifications because other threshing mechanisms in other countries cost upwards of $15,000 not including shipping to the U.S.
The final weight of the system is around 250 lbs, which far exceeds our expectations and specifications of the mechanism weighing less than 400 lbs. In addition, the system is also user friendly in many ways. An original specification was for the threshing drum to be accessible for maintenance through the concave being dropped down. Not only has this been achieved but there was a second access point added by the raising of the output. Video 8.2 in the appendix section shows the threshing machine in action. Only a small amount of crop was available for early testing, so the team will not know if the prototype was an absolute success until late August.
The project objectives originally was to build a thresher and cleaner using engineering principals to process multiple crops consisting of spelt, amaranth, buckwheat, beans and millet. This design was to be modular (flexible enough to add on to it later), energy source flexible and reproducible. In winter quarter we decided that to engineer and produce both a thresher and cleaner was too ambitious and that it was time to limit our scope. We decide to only build the thresher put make sure that this basic structure could be built off in the future to add a cleaner. Limiting the scope enable us to catch up and limit the cost of our project. We might have been able to come close in material cost to our projected values but would have been way off in the schedule if we had elected to continue with both machines.
Table 8.2 presents our specifications table from fall quarter with our prototype values filled in to show how our final design stacks up.
Overall the project was a success because the team was able to complete a testable prototype for the graduate school to work from. After seeing the machine in action, original concerns have been justified and need to be considered in the future.
The gap between the ceiling and the concave should be as small as possible and the crop should be fed to the thresher vertically are some examples.
FEATURES Fully enclosed threshing area Guards over moving parts Flexible frame and construction with bolt on parts Two access points Output that folds up to provide access to the drum o Concave that lowers to provide access to itself and the drum. o Variable pitch pulleys and various pulley combinations that allow for a wide range of crop capability. 4‐Stroke Internal combustion gasoline engine for power in ultimate location flexibility. Painted surfaces to discourage the formation of rust. SAFETY Warning: Captain Plant It thresher contains an Internal Combustion Gasoline engine. This engine contains hazardous chemicals, toxic fumes and hot surfaces that could cause harm or even death. The engine also contain flammable chemical that could result in a fire or even an explosion. For the complete overview of all warnings and risks please consult the engine manual. Warning: The Captain Plant It thresher contains moving parts that could cause serious harm or even death if anything is caught in the moving drum or in the belt system. While in operation: All guards should be in place and all adjustment bolts should be tightened down. The output should always be in the down position. UThere is NO reason why it should be in the upright position. While loading, the loader’s hand should never come close to the opening at the end of the input. If the crop gets stuck on the input or output turn off the thresher and only proceed when it is completely stopped. It is recommended that anyone with long hair working on or with the thresher put up their hair or where a hat in order to reduce that risk of their hair being caught in the belt or on the drum. This could result in very serious injuries. In adjustment or maintenance mode: Ensure that the motor throttle in set in its off position and it is recommended that the spark plug wire be disconnected and kept away from the spark plug. Be careful around the motor it may be hot. It is recommended that anyone with long hair working on or with the thresher put up their hair or where a hat in order to reduce that risk of their hair being caught in the belt or on the drum. It is recommended that the user not use gloves when adjusting the thresher as they could get caught and that could result in an injury. Warning: Never start the machine if anything is inside of the threshing area. This could result in injury or damage to the thresher. Caution: Various parts of the Captain Plant It thresher may get hot during operation. Caution is recommended after prolonged usage. Caution: Do not over lift the concave. This could result in the drum hitting the concave and broken parts. There is a chance of flying parts that could result serious injury. One should always spin the drum by hand before operation to insure that the drum will not hit the concave and all concave adjustment points should be tight. Caution: When the output is in the upright position it could easily fall and cause injury to any one below it. It should be tied down to make sure this does not occur. Caution: When working on or with thresher beware of any pinch points or sharp edges as one could get hurt.
OPERATIONStarting and Running the Thresher
1) Ensure that all the security knobs on the concave are tightened down and the concave is snug.
2) Rotate the threshing drum by hand to make sure that there are no restrictions to rotation.
3) Slide the idler pulley up on the slide to tension the belt (remember to only tension the slack side of the belt) and make sure that the belt is seated properly in all pulleys and is not rubbing on anything. All set screws on the pulley should be tightened and the nuts on the idler should be wrench tightened.
4) Replace the belt cover and ensure that the output is in the down right position.
5) Set the engine throttle to the desired speed, set the chock if needed and pull start the engine. For further instructions for starting the engine please consult the engine manual. Notice: Ensure that the engine is filled with oil before you start the engine, instructions to do so can be found in the engines user manual. Running the motor without oil can result in damage to the engine.