Theoretical determination of kinematic parameters of a nightshade fruit separator

Abstact. The work is devoted to the theoretical determination of kinematic parameters of a nightshade fruit separator both in direct and reusable way. The article has a research character, which is expressed in the fact that theoretically the analysis of kinematic parameters of a fruit separator, as well as works of leading scientists on the problem, their shortcomings and ways of solving these problems are indicated. There was determined the main trend of theoretical research. There were also justified the type of the proposed design, its theoretical description and the flow of the technological process. As a result of the work done, the design of the device for reusable harvesting of tomatoes and nightshade vegetables with the proposed working bodies is presented. The conclusions present the main results achieved so far.


Fig. 1. To determination of the roller's speed
The speed of point A in portable motion is defined as where -angular speed of the drum; R6-radius of the drum by rollers' circumference. Velocity of the point A in relative motion will equal to Vот= ωв • Rв where ωв and Rв are velocity and radius of the roller respectively.
The assumption that in the operation slit the roller must be flatted along the stem without slipping, the relative velocity of the drum must be equal to the sum of the portable velocity of movement and speed of rolling, that is Vот= + (1) where -velocity of the roller's flatting along the stem.
The value of the rolling speed is determined from the following considerations. In the process of plants' motion in the fruit separator, fruit remaining uncut on the root, and pass the path, S = L -c o s α At the speed of the device VM, the stem is in the operation slit of the fruit separator during time t, determined from the expression t = During the same time, the part of the stem located above the operation slit should completely roll down, that is, on the other hand, the same time can be expressed as follows: Equating the right parts of expressions (2 and 3) we = whence = (4) Given that the speed of flatting the rollers on the stem is directed vertically downward, and speeds of the portable and relative motion are in a plane perpendicular to the axes of rollers and drums, we design the found speed of rolling on this plane: Тhen Substituting the found value Vnp in the expression (1) we obtain = + ω + The angular velocity of the rollers in this case will be equal to = + And the number of revolutions relative to its own axis is determined from the expression n = where ωвis determined from the expression (7). Thus, the speed of rotation of rollers of the fruit separator depends on the speed of the harvester, the height of the plant's bushes, design parameters of the drum and rollers and the speed of rotation of the drum.
With known (originally set) parameters, it is determined by the expression (7). The fruit separator of the harvester consists of two multi-shaft drums rotating in different directions at the same speed.
The rollers on the drums are installed with a displacement relative to each other at an angle that provides vibrations of the stem.
Consider the scheme of occurrence of these oscillations ( Figure 2). Denote the angle between the rays radiating from the centers of the drums through φ. Let us assume that the rollers of the drums are shifted relative to each other by an angle , that is, when the drums rotate, the rollers of one drum move along the center of the inter-roller space of the other one. Consider two positions of the stem in the operation gap -the gap between the drums.
where nnumbers of rollers on the drum.
As shown above, the complete oscillation of the stem makes for the angle of rotation of the drums at an angle φ, that is, the number of oscillations of the stem per revolution of the drums, is equal to the number of rollers on the drum, that is nк об = (9) where nк об.  Consider the first case. In this position, the stem is in contact with the drum rollers at points A and B with further rotation of the drum, the point A will move away from the stem, and the point B will remove the stem from the original position in the direction of the axis X, coinciding with the direction of the line connecting the centers of the drums' circles. The stem movement will stop at the point E.
Thus, the movement of the stem in one direction (oscillation amplitude) -S can be expressed as the difference between segments O1E and О1Д.
S= O1E-О1Д The segment 01E is equal to the radius of the drum, which in turn is R б = R ц о в Rв where Rцов-radius of the circumference of the rollers' centers; Rв-radius of the roller. The segment О1Д is a sum of segments О1С and СД where The analysis of these expressions shows that at φ = 0 the speed of the stem movement is also zero and the acceleration reaches the maximum value.
Replacing the rotation angle in expression (10)  To separate the fruit, this force must be greater than the strength of the peduncle F P where Peffort necessary for fruit separation In this case the condition of the fruit separation is where m-mass of separated fruit. Thus, using expressions (7) and (20), it is possible to determine theoretically the main parameters of the fruit separator, angular velocities of rollers and drums.
In the result of carried out theoretical researches there were obtained the expressions which allow to determine the kinematic parameters of the separator of Solanaceae fruits which will allow more details and better to produce the design of individual operation items of fruit harvesters.