WAYS OF INCREASING PERFORMANCE QUALITY OF MOWERS AND HEADERS
The authors claim that cutting units should ensure clear cutting of crop stems. The paper considers the processes occurring during the cutting of herbaceous crops. The authors outline some indicators influencing the quality of stem cutting, analyze a process of interaction between a knife and fibrous tissues of crop stems, present specific features of cutting thin and thick stems of herbaceous crops, and examine the history of invention and performance improvement of cutting units. The paper features layouts and designs of a "classic" cutting unit currently installed on domestic machinery and a "Schumacher" cutting unit installed on most foreign harvesting machines. The authors list the pros and cons of these cutting units. They also emphasize a problem typical for "classic" cutting machines that is stem dragging into the opening of a cutting pair in case of an enlarged gap that leads to increased cutting forces. This problem is removed in the design of a "Shumacher" cutting unit. However, its operation is accompanied with an effect of double cutting, which also contributes to increased cutting forces. The paper contains diagrams and describes the operation principle of a cutting unit of a new design that minimize cutting resistance forces, which, in turn, decreases the power requirements of a knife drive, which ultimately leads to a reduction in fuel consumption. The authors present a design scheme of a patented knife segment allowing to increase the cutting unit reliability. The proposed design of a cutting unit features high resistance to transverse forces that arise in cutting. Their operation is not accompanied with an effect of double cutting and plant matter jamming that can improve the cutting quality and reduce power consumption of a knife drive.