Merry-Go-Round

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					     TA201
    ME Project
     2006-07 / II




Merry-Go-Round




                              Amit Verma - Y5060
                    Chintalagiri Shashank – Y5157
                       Kritika Bharghava – Y5235
                         Kritika Kashyap – Y5236
                            Rahul Kumar – Y5343
Acknowledgement


 We are grateful to Our Tutor, Dr . Sarkar and our guides in the TA Lab for their irreplaceable help and
valuable guidance . We greatly admire his patience and understanding in helping us out whenever any
difficulty came in our way. We also thank the other guides in the ME lab who provided help and
assistance as and when needed.

Last but not the least, we thank our instructor, Dr. V K Jain for providing us with such a wonderful
platform to give our ideas a shape .
Objective

To make a working model of a merry-go-round with rides having two motions. One motion of chairs
about their own axis and another vertically up and down motion of the horses.


Motivation

Joy rides have always tempted the young and the old alike. When given the opportunity to make our
very own machine which used power transfer mechanisms, the Merry-go-round popped into our minds,
ideal for our needs with its repetitive motions – rotations along its primary axis and the reciprocating
movements of the 'horses' in the vertical direction which is also tied in to the primary motion of the
Merry-go-Round. In addition, we also added a couple of rotating chairs, which rotated about their own
axis while revolving around the center of the machine.

Introduction and Mechanism Description

A 40 toothed bevel gear along with a 20 toothed pinion fixed with the handle is the basic element that is
responsible for the rotation of the main shaft and also responsible for all other motions in the model,
directly or indirectly. Above this is another assembly of a fixed bevel gear of 40 teeth and two pinions
of 20 teeth each. These pinions have horizontal shafts passing through them which are attached to
angles. these angles in turn are connected to a plate on which the chairs which rotate about their own
axis are mounted.this assembly is responsible for the rotation of chairs . The mechanism to move the
horses up and down was inspired by a crankshaft. The rotating motion of the shaft which is powered by
the rotation of the platform about a fixed gear is converted to oscillatory translatory motion by means
of a link system composed of two free to rotate joints.

MANUFACTURING PROCESSES USED
The following manufacturing process were used:

Lathe
It was used for the following operations:
1) To manufacture gears.
2) To file the shafts.
3) To reduce the cross section of the shafts as per the needs.

Milling:
We use milling machine for the purpose of teeth cutting of gears.

Drilling:
It was used to drill holes of various sizes in:
1) Base for fixing the shafts.
2) Shafts.
3) Gears.
Tools Used During Manufacturing

Tools used on Lathe

    1.   Single Point Cutting Tool on Lathe Machine
    2.   Three & Four Jaws Chuck
    3.   Dog Plate
    4.   Center Drill
    5.   Spanner

Drilling tools

    1. Drill chuck with key
    2. Drills (in mm): 3.0, 3.3, 4.5, 5.2, 6.5, 7.0, 8.0, 12.5, 12.7

Miscellaneous Tools

     1. Spanner Set
     2. Screw driver
     3. Heck Saw
     4. Dog Carrier
     5. Vernier Caliper
     6. Steel Scale (12”)
     7. C Clamp
     8. Hammer
     9. Center punch
10. Round File 12”
11. Bastard Files (Smooth & Coarse)
12. Knife Edge files
13. Tap set (¼”, 3/16”) with handle
14. Marker
15. Pliers , Vice etc.
Cost Estimation

Sr.     Heads of Expenses        Cost per Unit       Number of       Net Cost
No.                              (Rs.)               Units           (Rs.)

1.      Mild Steel               35/kg               13.75 kg        481.25

2.      Electricity Cost-Lathe   50/hr               15 hrs          750

3.      Electricity Cost-        75/hr               5 hrs           375
        Milling
4.      Electricity Cost-        40/hr               2 hrs           80
        Drilling
5.      Electricity Cost-        30/hr               1hr             30
        Cutting
6.      Nuts and Bolts           60/kg               0.15 kg         9
7.      Unskilled labor          95/day=11.875/hr*   5 men x 7labs   1246.875
                                                     x 3 hrs/lab
                                                     =105hrs
8.      Skilled Labor            150/day=18.75/hr*   6 hrs           112.5

Total                                                                3084.625

*1 day taken as 8 hrs/day of labor

Overhead expenses: 5% of Total Cost = Rs.154.23

Final Cost : Rs. 3238.85

Approximate Cost of the Project: Rs. 3300/-
MANUFACTURING DIFFICULTIES

• Dimensional accuracy: - Moments when we needed two holes with a common constraint, it was
necessary to make them properly aligned so as to fulfill that constraint. This was the time when we
faced difficulty in maintaining dimensional accuracy. For example while drilling two holes on different
angles to make the shafts pass through them and rotate smoothly.

• Link Mechanism: - In order to rotate freely it was important to have some gap between the various
parts of the link mechanism, but it was also necessary to joint the mechanism with other parts. Screws
available in the lab was not serving this purpose in our design so we used rivets and washers for this.

• Welding: - According to our design one gear was to be welded with the base part. It was difficult to
weld that gear because teeth of other gears were susceptible to be spoiled by the extra molten metal
coming out from the welding region. We overcame from this difficulty by covering them by wet
clothes, but while welding central passage for main shaft got misaligned. We drilled that passage and
extra material came out and it became proper.

• Machine availability: - Non-availability of a particular machine at the time when it was required
affected manufacturing time. We could not do parallel machining of independent parts.
All parts were serially processed and assembled and total time in finishing our project increased
reasonably.

				
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posted:8/7/2011
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