Rice transplanter

DESIGN AND

FABRICATION OF RICE SEEDLING

TRANSPLANTER

A transplanter is an agricultural machine used for

transplanting seedlings to the field.

This is very important as it reduces the time taken to transplant seedlings (when compared to manual transplanting), thus allowing more time for harvesting.

Hence, Paddy Transplanter is one type of transplanter which plants paddy seedlings to the field.

PADDY TRANSPLANTER

Paddy is the rice grain with husk. It is a wetland crop,

which extensively grows all over the world. Rice cultivation is well-suited to countries and regions

with low labour costs and high rainfall. In 20th century, transplanter was invented to plant the

seedling into the land which reduced the human efforts and consumed less time.

INTRODUCTION

In early days, People used to plant the seedlings by their

hands. They used the ropes to plant the seedlings.

MANUAL METHOD

The existing paddy transplanter involves the complex mechanism it

creates problem like Frequent replacements of links, Farmer cannot repair by their own, Pulling force required is more. Costs about Rs. 18000

PROBLEM DEFINITION

DESIGN VIEW

Paddy seedlings are kept in the tray and allowed to flow

down under gravity. The fork which is attached to shaft picks up the seedlings

from the tray and keeps it in horizontal position on the skid.

The motion for the shaft is given by hand using chain and sprocket arrangement.

Here, Simple four bar mechanism is used to plant paddy seedlings into the land.

WORKING PRINCIPLE

Four Bar linkage Chain Sprockets Tray Shaft Fork

COMPONENT DESIGN

FOUR BAR LINKAGE

The four bars in link are as follows Crank - can rotate a full 360 degrees Lever - can rotate through a limited range of angles Connecting rod – connects the crank and lever Fixed frame – fixed part in linkage.

Length of crank = 3.5 units Length of lever

= 6 units Length of connecting rod = 10 units Length of fixed frame = 8 unitsGRASHOF CONDITION S+L ≤ P+Q 3.5 + 10 ≤ 6+8 13.5 ≤ 14Hence Grashof condition is satisfied. 

DIMENSIONS OF FOUR BAR LINKAGE

• We use Sprockets for hand driving wheel and in the shaft for rotating the fork and four bar mechanism.

Calculation of Speed of RotationZ1=No. of teeth on sprocket pinionZ2=No. of teeth on sprocket wheelN1=Speed of rotation of pinionN2=Speed of rotation of wheel

SPROCKET

Speed of wheel driven by hand N2=25 rpm

(optimum value)No. of teeth in sprocket wheel Z2=40

No. of teeth in sprocket pinion Z1=18Transmission Ratio ‘i‘ N1/N2= Z2/Z1

Z2/Z1= 40/18 = 2.2

Therefore, N1 = 2.2 x 25Speed of rotation of pinion = 55rpm.

D1=P/sin(180/Z1) =2.2/sin(180/18) =12.6 units D2=P/sin(180/Z2) =2.2/sin(180/40) =28.4 units

DIAMETER OF SPOCKET

The chains are used to transmit the power from hand

driving wheel to the shaft in which forks are attached and it is also to transmit the power to the four bar mechanism

CHAINS

Length of chain: L = Lp x p

Where Lp is the chain length in pitches (i.e. approximate no. of links) p = Pitch of chainNow to find Pitch P: C=p x Cp

Cp = Approximate Center distance in pitches =(30 to 50) DDHB Assume Cp =50 Where C is the center distance and assumed it as 110 unitsThen C=p x Cp

110 = 50p p= 2.2 units

Calculation of Chain Length

Now to find length Lp,

Lp = 2Cp +0.5 (Z1+Z2)+ ((0.026x(z2-z1)2)/Cp) (approx)

Where Cp is the approx. center distance in multiples of pitches Lp = 2x50+0.5 (18+40)+ ((0.026x(40-18)2)/50) =129.25 units

Length of chain =Lp x p =129.25x22 =284 units

Tray is used to keep the paddy seedlings on the

transplanter. Sheet metal is metal formed by an industrial process into

thin, flat pieces.DIMENSIONS OF TRAY

Length of sheet metal = 53.5unitsBreadth of sheet metal = 26 units

Thickness of sheet metal = 0.1 units

TRAY

Shaft is a revolving rod that transmits motion or power Here, the one shaft contains forks and another shaft

contains four bar linkage and power is taken from the hand driven wheel by chains and sprockets.

SHAFT DIMENSIONS: Length of the shaft = 30 units (it is space required between the paddy seedlings)Diameter of shaft = 2 units (it is the optimum diameter for 30cm shaft

SHAFT

Fork is used to pick up the paddy seedling from tray and

to keep it on skid. There are two forks attached to shaft and distance in

between two fork is 30units. The motion to fork is giving by shaft. Total length of fork is 28units

FORK

DESCRIPTION EXISTING MODEL PROPOSED

MODEL

WEIGHT 25 15

AMOUNT (Rs.) 18000 9000

EXISTING MODEL VS PROPOSED MODEL

Reduces the human effort to a maximum extent. Simple design compared to the existing model. Easy to repair by Farmers itself and maintenance is less. Pulling force is greatly reduced by decreasing the

weight of the model .

ADVANTAGES

Transplanter can be operated continuously only for 4-5

hours. Healthy persons can only be able to pull the

transplanter.

LIMITATIONS

24