Machinery & Energetics

Shearing efficiency is highly dependent on the performance of the shearers. Due to the mechanical energy of the machine, only the cutting of woolen fibers occurs, and its movement on the surface of the animal's body is carried out by a person – the shearer. A highly skilled shearer when shearing fine-wooled sheep with a wide-grip comb (b = 76.8 mm) uses about 90% of its width, low and medium 50–75%. The most professional shears usually work with narrow gripping combs (b = 57.6 mm), because narrow gripping combs provide less resistance on the shear's hand when clipping and make it possible to move the machine at a higher speed than wide-gripping combs. So, the shear's performance depends on the following factors: traction force – P, movement speed – V, operating time (duration of the working process) – t. Theoretical calculations showed that with the maximum shear force, the optimal feed rate is 0.93 m/s, and the load on the shear arm should not exceed 30.6 N. An increase in the shear arm load of more than 30.6 N causes a decrease in the feed rate, and, accordingly, a decrease in productivity. In the world practice of shearing sheep, there are two most successful technical solutions: a reverse translational shearing device and a rotary one. The analysis of each of the options showed that in the reciprocating cutting device, if the technological parameters are not observed, the quality of work sharply decreases (the content of the cut increases) and the power consumption increases. Cutting or re-trimming is undesirable during the cutting process, their total content in the fleece should not exceed 1%. If the latter depends on the qualifications of the shearer, then the first depends mainly on the combination of geometric, design and technological parameters of the cutting apparatus and the shearing machine. Shearing of wool with a rotating character of the knife movement provides that when passing over an already trimmed surface, the wool is only combed due to failure to meet the conditions for pinching the material. The rotary movement of the knife allows you to get rid of repeated cutting of the wool (chapping) and leads to a decrease in the energy intensity of the process within 20%. We have developed a stand that has the ability to determine the force of resistance to the movement of the clipper in the woolen layer and the power consumption of the drive of the clipper, which is used for clipping, by changing the speed of the clipper. Comparing the MSU-200 and the rotary shearing machine, it can be noted that the power consumption of the developed machine, in comparison with the base one, has decreased by 2.2–2.3 times. The force of resistance to movement has decreased by 1.2–1.4 times, and the amount of cut has also decreased by 3.2–3.5 times

sheep shearing, wool, shearing machine, re-cutting, chaffing