This toy has rack and pinion, cam follower and slider crank mechanism. The combination is really original .

1. A Project Report On
_________________________________________________________________________
DANCING BOY TOY
THEORY OF MACHINES
MEL303
Semester 2014-15
Indian Institute of technology Ropar
____________________________________
Submitted To:
Dr. Jitendra Prasad
Submitted By:
Aashish Kumar Kholiya (2012MEB1083)

2. Acknowledgement
I would like to show my sincere gratitude to the course instructor of “theory of
machine” Dr. Jintendra Prasad. It’s actually because of his teaching and the concept
that he explained in the class that helped me to come up with this project that
involve cam and gears. His constant support and motivation has aided me in
completion of the report and hopefully it would assist me in making the working
model of the toy that goes by the name of Dancing Boy. I would also like to mention
Mr. Rajeev who has manufactured the parts.

3. Introduction
It is a simple mechanism toy which consisting of one gear pair and one cam-follower
.It is seven bar mechanism .When we rotate link 2 by hand or DC motor the slider
moves in –X direction to +X direction shown in figure A. It seems like the boy is
dancing and with this flat face follower goes in –Y direction to +Y direction and it
seems like cap of dancing boy goes up and down. When cam rotates his face is also
move.
Components
(1)Cam with Gear teeth
(2)Slider with Rack
(3)Two Binary joints
(4)Base
Mechanism Used
(1) Rack and Pinion
(2) Cam follower
(3) Slider crank

4. Kinematics and Dynamic analysis:
Number of link, L=7 Number of joint, J=6+2*0.5
Overall Degree of freedom M=3(L-1)-2J=1
*(Using SAM Ultimate design Mechanism Software)

5. A binary Link is connect with ground with revolute joint form one end and another
end is connected with another binary link which is connect by revolute joint with a
slider which having rack on its upper face and it is stomach of boy. And pinion is
connected by full joint with it and upper surface of pinion is working as cam, cam
is face of boy it is connected with a flat face follower, it is cap of boy. Flat face
follower is connected by half joint with another slider shown in figure at joint
8.when we rotate link 2 force transmits to link 3 , because link 3 is rigid it transfer
force component to slider which moves in XZ plane and slider which have
properties of rack also . Rack gives motion to pinion then link 3 rotate about point3
in some range [-A, B].and it seems like boy is moving his stomach and face .at this
time his cap is goes up and down .his legs move with slider which partially on
ground.

7. Fp is then transmitted to pinion.

8. Drawing and Renderings
Cam
Slider (Rack)

9. Base
Flat Face Follower

10. Renderings