Pedal-Powered Rotavator Employment - Report Example

Pedal-Powered Rotavator by Student’s Name Code+Course Name Professor’s Name University Name City, State Date 1. Developing the brief Mechanisation is one of the major steps that man has seen over time. It has affected the number of people who working on the farms. Population on the other hand has been increasing from time to time. When the population increases, so is demand for food to feed people. It is because of this need that mechanization was developed to aid man. The work that was initially performed by ten men can be performed by one man with greater accuracy, minimal resources and very short time. Rotavator is one of the greatest farm equipment that man has invented to simplify the work in the farm and to as well increase productivity. Some of the rotavators found in the market are either powered by tractors or motors. However, in this case, the power source is either human hands or foot. Either way it has to be very efficient to reduce the incidences of fatigue without meaningful work. Such a rotavator has to have a system of power transmissions for effective working. It is for that reason that peddles are to be powered by hands for ease of design and steering. Chain and link will also be applied. 2. Sustainability With increased mechanisation and industrialization, there has been a lot of waste materials that have been disposed off into the environment. Some of these materials are non-biodegradable while others are very harmful both to the environment and to men. It has become very necessary that materials used should be those that can degrade and be absorbed into the environment. It is for this reason that the materials adopted in the design of peddle powered rotavator has been with use of materials which are both reusable and recyclable. Steel is one of the common metal alloys that have been known to man for many centuries. Steel can be casted again and again for as many times as man would want. Even if it would be left discarded into the open environment steel would last and break down into two iron compounds which are very harmless to many and other living organisms in the environment. Recycling and reusing are very important parts of taking care of environment. The environment should be kept clean for future generations. 3. Mechanical analysis In this case there are several assumptions which are to be applied here. One of the assumptions is that the power available is 200N. For this system the chain is driven by a sprocket which is peddled by hand. Taking the radius of the sprocket to be 15cm, then power and torque can be calculated as shown below. Power = force available * speed of the moving parts Equation 1 Assuming that the speed of the work is 2m/s Power = 200N * 2m/s = 400W Therefore the power available is 400W Torque provided can be calculated as shown below Torque = radius of the sprocket * force Equation 2 Torque = 200N * 0.075m = 15Nm The blades digging the soil is of a radius of 30cm (0.3m). Therefore the force available for the blade can be calculated as shown below if the efficiency is 100% Torque = 15Nm 15Nm = 0.3 * force Force= 50N The velocity ratio = Equation 3 The flywheel turned by the sprocket through the chain is 10cm Velocity ratio = 30/10 = 3 4. Concept design The figures below show how the system is operating; Figure 1: The front view of the peddle power rotavator 5. System interaction The system design is very simple both in design and operation. It is mainly made of chains, sprockets, peddles and the components which are used for digging. The peddles are driven by hands for the ease of turning effectively. When peddles are rotated, they turn the sprocket which in turn causes the sprocket 2 to turn. Sprocket 1 and sprocket 2 are connected via a chain. The sprocket 2 is then connected by wheel 1 via a power shaft. Flywheel 1 powers then the whole system starts digging after turning the flywheel 2. Belts in this case would not be the best because of slipping. On the other hand chains minimize the slipping effectively. Gears would have worked equally well only that they are expensive to buy and/or machine. Chains though relatively weaker than gears will work perfectly well. When slipping is minimized the efficiency rises. 6. Serviceability Failures and break down are inevitable in any mechanism and system. It is therefore important to have methods of repair and replacement so that the system can be in the most convenient shape. Steel metal used to develop this system has high resilience and can withstand harsh forces of the environment upon which it will be subjected. Impulse force may be present due to the rock particles present. Soil is a developed from rocks. It is therefore likely to find several pieces of rocks in the soil of different sizes and hardness. Steel can withstand such for relatively long time. However, in the event that it would fail, the system is so simple that the person with the least technical know-how would perform the repair operation with no difficulties at all. The whole system does not have to come down for the replacement to be done or the repairs to be performed. There are several subsystems which would be used instead. Components used in the development of the rotavator are all standard and can therefore be found easily in the market. So in the event a failure occurs, replacement or repairs can be performed with a lot of ease. 7. Selecting materials Material selection is an important part of design. This is so because even if the design if working well and the whole system fail during testing, the problem will have to be traced all the way to the design. Therefore, if the materials are well selected, the mechanism will work for a very long time without replacements or repairs. This increases the life span of the system and its reliability. Also when materials are well selected, efficiency is guaranteed. It is for this reason that steel materials are selected. The chain is strong and so is the sprocket. 8. Geometry stability For the system to work well, it has to be of the correct geometry. For this reason, sprocket 1 and sprocket 2 must be vertically above each other. The axes of the sprocket 1 and sprocket 2 must be perfectly horizontal. The power shaft connecting flywheel 1 and sprocket 2 must be horizontally oriented. The fly wheel 2 must always be vertically below flywheel 1 at any given moment. The axle supporting the digging components is also horizontal so that the power and force can be well distributed. 9. Operational reliability As it was reported earlier, steel is a very strong metal and endure in very harsh weather conditions. Thermal stresses as well as tensile stresses can be comfortably handled by steel. Also, steel is cheap. Due to its high ultimate stress, steel is likely to give the system a very long life span. Due to its ability to withstand harsh working conditions, its reliability is quite high. That is to mean that for the ten times one may require to use the equipment, it would be only one or two times that the system would be found not to be in a good working condition. When water is kept away from steel, it can last for more than one century. Moisture on the presence of air causes steel to rust and therefore weakening it. It is estimated that this system will work for at least eight months without requiring replacement or repair. 10. Environmental robustness Steel is a very strong metal. However, this is limited to the environment on which it is used. In places where there is plenty of water and oxygen, the lifetime of the steel metal is reduced significantly. It will not be possible to cover the system. The only thing necessary is occasional lubrication. After using the system, it has to be maintained by washing away all the dirt from the garden and ensuring that it does not have to work in watery places for more than eight hours. Painting may be necessary for the parts which are not in touch with the ground. For the rotating parts, the dirt has to be washed away from time to time to prevent clogging. The system is operated solely on the human effort and therefore high efficiency is necessary to prevent exhaustion of the operator without doing significant amount of work. References FOOD AND AGRICULTURE ORGANIZATION. (1962). I. Heavy duty rotavator. II. Dozer with teeth. Rome, FAO. HOWARD ROTAVATOR CO. (1983). HR8 Rotavator operating instructions & parts list. Norwich, Howard Rotavator Co., Ltd. HOWARD ROTAVATOR PTY. LTD. (1961). Howard rotavator owner's handbook: terrier rotary hoe reverse gear model. Northmead, N.S.W., Howard Rotavators. INTERNATIONAL SEMINAR ON DOWNSIZING TECHNOLOGY FOR RURAL DEVELOPMENT, KHUNTIA, S., PARIDA, A., & MISRA, V. N. (2003). Proceedings of the International Seminar on Downsizing Technology for Rural Development, ISDTRD-2003, October 7-9, 2003, Regional Research Laboratory, Bhubaneswar. New Delhi, Allied Publishers. MALANG, V. L. (1998). Inventions & innovations: a glimpse of the Filipino legacy. Tagig, Bicutan, Metro Manila, Philippines, Goodwill Bookstores. Read More