Bi-directional Dual cutting edge Rotavator

INTRODUCTION

The ROTAVATOR (derived from rotary cultivator) or rotary tiller is a tillage tool primarily comprising L shaped blades mounted on flanges, which are attached to a shaft that is driven by the tractor power take off (PTO) shaft. It is mainly used in agriculture for loosening of upper layer soil to create seedbed. The rotavator has higher soil mixing capacity compared with other plough machine and it has good weed cutting capability and it leads to the water air, thermal and nutrient of the soil is improved. The rotavator can be easily adjusted for various working depths for soil bed preparation.

Many types of rotavator blades are available in market. Those are C shape, L shape and J shape

After reviewing research literature of past studies the following general conclusions are drawn

• The tiller has a huge cutting capacity, mixing to top soil preparing the seedbed directly. And also it has seven times more mixing capacity than plough.

• L shaped blades are better when compared with C or J type blades in trashy conditions as they are more effective in killing and they do not pulverize the soil as much.

• Normally the average service life time of a rotavator blade is fifty hours.

Hence it is important to improve the durability of blade by modifying geometry of existing rotavator blade.

In this work the design modification carried out in L shape blade. Because the L shaped blade is most widely used in the agriculture land.

Old Design

The blade and the gearbox are designed in SolidWorks. The gearbox was designed to make the rotavator rotation in both the direction at the same speed. So, the bevel gears were designed keeping the gear ratio same as of the previous gearbox. To change the course of the gearbox dog clutch was used to make the engage and disengage the gear from the shaft. The engagement and disengagement are done when the bevel gears are stationary. So, the wear and tear of the clutch is minimum while engaging with gear. The blades get the speed of 264 rpm and 995.05 Nm. The rotavator blades designed for better working life. So, that farmer can use it longer thus decreasing its replacement cost. The blade is a double cutting edge with same cutting angle and thickness of previous single cutting edge blade. Chrome steel is selected as it is more corrosion resistant.

new design