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DATE : 06.11.2012

TITLE : COCONUT SHELL BREAKING MACH

OBJECTIVE :

Design a machine to break dehusked coconut

Coconut water needs to be collected cleanly (without

contaminating water)

Split the coconut into two preferably size of two halves

INTRODUCTION :

Coconut shell breaking machine is simply designed to break the

coconut and collect the coconut water without contamination. It is consisted of very

simple mechanisms to hold or clamp the coconut tightly to break the coconut and then to

collect the coconut water for the easiness. These mechanisms are categorized into 3 main

parts. Splitting mechanism feeding or clamping mechanism and filtering mechanism.

So under splitting mechanism the hammer design is described and also

under feeding mechanism the clamping unit is described. The coconut water collecting

tank is described under the filtering mechanism.

The concept is well described with calculations throughout the report

to give a better understanding. The machine design is actually targeted to mass

production since high effectiveness can be achieved by this machine in the long run. Also if

needed this can be modified for the domestic usage as well.

Figure 1: Complete Machine

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Declaration

We hereby declare that the project “coconut shell breaking machine”

submitted on ME209-Machine Design I is a record of original work done by us under the

guidance of mechanical department academic staff

30.09.2014

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Design Concept:

In this Coconut shell Breaking Machine mainly three mechanisms can be

identified. They are;

1. Clamping Mechanism

2. Splitting Mechanism

3. Filtering Mechanism

1. Clamp

Figure 2: The Clamp

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When the machine is considered clamp is the precious element in the machine. In this

clamp it can be identified mostly 3 main parts

Cutting tool that connected to hammering plate

Clampers

Food quality thin rubber layer

Cutting Tool

Cutting tool is manufacturing by casting and forging mechanisms. The cutting

tool is designed considering two main things. They are

a) Reduce the rebound of coconut due to rubber

layer

b) To break apart coconut in two parts perfectly

When a coconut is needed to splited first of all the

cutting tool should have to pulled upwards and hold the

coconut in between the clampers. Three eyes of coconut

should be placed near to a clamper. It is was placed

correctly coconut ribs will be perpendicular to inclined

shaped walls.

In the cutting tool a big spring can be identified it

was placed to give a downward thrust to the coconut

when it was clamped. The cutting tool can be moved

along the oval shape easily. That path is designed to break

the coconut fully.

Clampers

Clampers were attached to clamp holders by using two springs for each clamper.

Four clamper were this design when a coconut is placed the clampers will be gone.

Figure 3: Cutting tool

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Backwards and it will be stable easily due to the spring wall of the clampers were made

with ruff surface to coconut perfectly

A food quality thin rubber layer was placed under the clamps. It was placed due to main

reason (fig 2.) It is;

Due to the impact force coconut may cause to jagged break it would happen if

coconut is contact rigid surface from down side of the shell.

The coconut water should be collected without contaminating. Therefore a food

quality a thin rubber layer is used. But rubber layer is not a smooth rubber layer. It is bit

ruff and it is 6mm in height. Due to this rubber layer coconut will not contact rigid surface

during the impact force. Therefore a jagged break couldn’t be happen from the down side

of the coconut. That would help to have a smooth shell break.

2. Filtering Unit

When coconut shell breaking machine is considered coconut water is a critical point.

In this machine coconut water filtering is precious task. To do that some features were

added to the main design.

Figure 4: Springs

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When clamp design is considered inclined shape can be identified.

When a coconut is fully split coconut water will be drained downwards due to these

inclined shape walls it will be flowed over that walls easily.

Then coconut water will be drained through draining hole. Then water will be collected to the tanks that placed under clamps. In every tank a food quality disposable net is placed inside and rigid horse was placed under every tank for every clamp. A tank was allocated to collect coconut water effectively

To the end of that rigid pipe a flexible food quality rubber pipe was connected. To the other end of it a food quality another net will be connected to second stage of filtering process. After the second filtration process Coconut water is collected to main tank. That tank also made out of PVC.

3.Hammer

Figure 5: Filtering Unit

Figure 6: Hammer

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Hammer is manufactured using heated metal. Hammer is placed over moveable a metal

cube. That metal cube can be moved over the moveable path. It can be discontinued at

every clamp

When Hammer is considered mainly four parts can be identified in this design. Hammer is

used to give the impact to the coconut shell. To pull up the hammer two metal part were

installed on hammer head.

Hammer is installed over that movable metal cube. Hammer arm is

connected to the base plate by a spring. To prevent the spring from buckling a piston

system is installed inside the spring. Due to the spring it is somewhat harder to pull the

hammer. But it will go downwards instantly. When hammer touched the hammering plate

the impact is transferred. To pull up the hammer to small arm were added to the hammer

design.

Due to the spring, hammer will come downwards speedily. If the is spring is not installed

hammer will come downwards slowly due to its own weight. It want be enough to make

an impact. Therefore spring system is used in this design.

Figure 7: Metal Cube

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Figure 8: Hammer Design

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CALCULATIONS

1. To break the shell of a coconut 3 pound is needed. Therefore the impact load is

considered as 50N.

DATA

Input impact load (F) = 50N

Diameter of hammer head ( ) = 25mm

Diameter of hammer plate ( ) = 40mm

Length of the spike ( ) = 40mm

Bearing failure of the hammer;

[F.O.S is considered as 4]

m

= m

2. Bearing failure of the hammering head;

m

= 15mm

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3. Shear failure of hammering head;

3.7 mm

= 15mm

4. Shear failure of hammer head;

F/

Da2 2.214 m2

1.5mm

= 10mm

Da is calculated at two points

Shear failure at hammer head Da 1.5mm

Tensile failure of the arm at the hinge point Da 6.6mm

Therefore Da is taken as 10 mm.

5. Shear failure of Bolt at the hinged point;

F/

1.05mm

= 5mm

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6. Tensile failure of the hammer arm at the hinged point

F/

F/

(

- (

0

0

= 10mm

7. Bending failure at hammer arm;

By using Bending Formula;

2

) (

)

162mm

162mm

8. Crushing failure of Knife edge (Cutting Tool)

2.63 m

= 6mm

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9. Shear failure of Knife edge (Cutting Tool)

1.8

20mm

10. Bending failure of cutting tool arm (stem of the cutting tool)

2.2

= 80mm