Page 30 - CITS - ED - Mechanical

ENGINEERING DRAWING - CITS

Fig 1

Exercise 2.10

Construct an involute of a circle of diameter 30 mm by Concentric method (Fig 2)
• Follow the first four steps of the Radial line method. (Ex.2.1.1)

• Draw the concentric arcs, from the centre of the circle through the divisions 1,2,3.... etc to cut the tangential
lines drawn from 1',2',3' etc at points P ,P ,P etc.
1
2
3
• Join points P , P , P by a smooth curve and form the involute of the circle.
1 2 3
Fig 2

Exercise 2.11
Construct an involute of square of side 25 mm (Fig 3)
• Draw a square ABCD and extend the sides.

• 'A' as centre and radius 25 mm, draw the quadrant B.
• 'D' as centre and radius D-1, draw a second quadrant 1-2.
• 'C' as centre and radius C-2, draw a third quadrant 2-3.
• 'B' as centre and radius B-3 and draw forth quadrant 3-4.
• Now the curve 1-2-3-4 is the involute of the square.

17
CITS :Engineering Drawing (Mechanical) - Exercise 2