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Threshing is a key part of agriculture that involves removing the seeds or grain from plants (for example rice or wheat) from the plant stalk. In the case of small farms, threshing is done by beating or crushing the grain by hand or foot, and requires a large amount of hard physical labour. A simple thresher with a crank can be used to make this work much easier for the farmer. In most cases it takes two people to work these: one person to turn the crank and the other to feed the grain through the machine. These threshers can be built using simple materials and can improve the efficiency of grain threshing. They can also be built with pedals, or be attached to a bicycle, so that the person operating it can simply pedal to reduce the work even more and make threshing faster. Threshers can be made in a number of ways using simple tools, and can be used in the harvesting of maize/corn, rice, wheat, sorghum, pearl millet, and any other grain or seed that must be separated from a stalk. The attachment of a thresher to a pedal-system can be built with basic materials. Two versions are the pedal-powered thresher which is built as one piece and the attachment to a bicycle for a regular thresher with a crank.〔 Pedal-powered threshers have been suggested or made available to farming communities by governmental or non-governmental organizations. It should be remembered that there are some disadvantages to these threshers and their impact in the specific region should be researched before being suggested. ==Threshers== Thresher are many different designs for threshers and they can be made from wood or metal. The shape of the thresher can vary, but it must include some main parts: *A cylinder with spikes or loops that will pull the grains off the stalks as they are held onto the cylinder, or pushed through.〔 These cylinders can be made from metal, or a progression of wooden boards that form a wheel.〔〔〔 Different designs that will work better for different crops. For rice it has been found that wire loops should be used and the best spacing for these loops is approximately 40 mm apart and 60 mm high.〔 This study was performed in the North Western Himalayan region of India. Loops are generally preferred for crops with small grains such as wheat, sorghum, pearl millet, etc. For corn/maize is it is suggested that solid spikes, 6 mm long, and spaced 200 mm apart be used.〔 This study was done in Nigeria. Nails may be used as a rudimentary form of spikes.〔〔 A cylinder without spikes or loops can be used if the grain is being ground against a surface. A model of this type was developed by the Massachusetts Institute of Technology for a project in Guatemala.〔 *A cover behind the cylinder is required to prevent grain from flying out of the machine while threshing.〔 *Attachment of crank to cylinder with use of bolts and metal pieces. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Threshers, pedal powered」の詳細全文を読む スポンサード リンク
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