National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692 Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
Weeding is an important but equally labour intensive agricultural unit operation. Non-chemical weeding is required for ensuring food safety. With mechanical weeding methods, it is possible to control weeds in a way that meets consumer and environmental demands. Mechanical vibrations have immediate and long term effects upon the human body. It depend upon the duration of exposure and the frequency of vibrations. For walk behind machines , vibrations are transmitted to the operator through his hands while in case riding type, vibrations are transmitted to the operator through seat as whole body vibrations (WBV) and through his hands as hand-arms vibrations (HAV). The power weeder was designed and developed in department of farm Machinery and power CAET, VNMKV, Parbhani. Hand arm vibration study was conducted with four rubber interventions I 1(A1B1), I2 (A1B2), I3(A2B1) I4 (A2 B2) A1 Synthetic rubber (Styrene-Butadiene Rubber); A2 Foam rubber (Nitrile rubber) B. Hand Grips soft handgrip of foam rubber ; B2 general hand grip}, three speeds (S1=1.2 kmph, S2=1.5 kmph, S3=1.8kmph) and two type of Blade. Straight blade, and Rotary blade. It was observed that In weeding with straight blade, the vibration magnitude increased with speed. The vibration magnitude in x direction was higher than y and z directions. The x axis acceleration exceeds 1h, 1.5h, 2h exposure limit at 1.8 ,1.5.1.2 kmph. The peak value in x direction was found at 50 Hz and around 160 Hz. it is observed that vibration levels were higher in x-direction. The vibration magnitudes were concentration over a frequency range of 0-20 Hz. With intervention I1 i.e Synthetic rubber with soft foam rubber hand grip ,there was reduction of 34 percent and 30.5 percent in HTV at speed of 1.8 kmph for straight and rotary blade respectively followed by I2,I3, and I4 has the lesser reduction in the HTV but it has less HTV values than the control i.e no intervention. Maximum time of exposure to vibrations was increased from one hour to two hours in case of rotary blade at all three speeds i.e. 1.2,1.5,1.8 kmph and the period was increased from two to four hours in case of straight blade weeding operations.
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