Extremely helpful for Engineering Drawing in BCA -3rd SEM!!

1. Content
1. Acknowledgement
2. Certificate
3. Definition of involute
4. Types of involute
5. Involute of composite shapes
6.
1. Half Circle and half Triangle
7.
2. Half Triangle and half Hexagon
8. Involute of square
9. Involute of polygon
10. Conclusion
11. Bibliography

3. INVOLUTE
• INVOLUTE is a locus of a free end of a string
when it is wound round on a circular pole.
• It is also a curve obtained from another given
curve by attaching an imaginary taut string to
the given curve and tracing its free end as it
is wound to that given curve, or in
reverse, unwound.

4. TYPES OF INVOLUTE
• Involute of a circle
1. Having string length πD.
2. Having string length greater than πD.
3. Having string length less than πD.
• Pole having composite shapes.
• Rod rolling over a semicircle.

5. An involute of a pole which is in shape of
half pentagon and half triangle.
P2
2
P3
P1
3
1
4
P4
o
P5
P

6. An involute of a pole which is in a shape of half
circle and half triangle.
P2
P1
3
P3
4
2
5
P4
O
P5
1
P

7. Involute of a square
P2
P1
P3
4
P4
3
5
P5
6
2
1
7
P6 P7
o
P

8. P3
Involute of a polygon.
P2
3
4
P4
P5
2
1
50
P0
P1

9. Conclusion
Thus we can conclude that involutes of composite shapes can be
generated by using different fundamental shapes such as circle,square,triangle
etc. and by linking circular and linear movements. This uniqueness has become
fertile soil for many inventions that have simplified gear manufacturing
and inspection.
Even today, when computers can synchronize axes for creating any curve,
advantage of involute properties can be very helpful which simplifies the
synchronization of machine movements and reduce the number of variables to
monitor.
The involute of composite shape is also an important shape in
gas compressing, as a scroll compressor can be built which have proven to be
quite efficient.