Involute

Involute of Circle


1 ] Draw the involute of a circle. String length is equal to the circumference of a circle.

Solution Steps:

  1. Point or end P of sting AP is exactly πD distance away from A. Means if this string is wound round the circle, it will completely cover the given circle. B will meet A after winding.

  2. Divide πD ( AP ) distance into 8 number of equal parts.

  3. Divide circle also into 8 equal parts.

  4. Name after A 1, 2, 3, 4, etc up to 8 on πD line AP as well as on circle ( in anticlockwise direction).

  5. To radius C1, C2, C3 up to C8 draw tangents from 1, 2, 3, 4, etc to circle.

  6. Take distance 1 to P in compass and mark it on a tangent from point 1 on the circle.

  7. Name this point P1.

  8. Take 2P distance in compass and mark it on the tangent from point 2. Name it point P2.

  9. Similarly, take 3 to P, 4 to P, 5 to P up to 7 to P distance in compass and mark on respective tangents and locate P3, P4, P5 up to P8.

  10. Join them in a smooth curve it is an involute of a given circle.


involute of circle

 

2 ] Draw the involute of a circle. String length is more than the circumference of circle.

Solution Steps:

  1. In this case string length is more then πD.

  2. But remember whatever may be the length of string, mark πD distance horizontal i.e along the string and divide it in 8 number of equal parts, and not any other distance.

  3. Name after A 1, 2, 3, 4, etc up to 8 on πD line AP as well as on circle ( in anticlockwise direction).

  4. To radius C1, C2, C3 up to C8 draw tangents from 1, 2, 3, 4, etc to circle.

  5. Take distance 1 to P in compass and mark it on a tangent from point 1 on the circle.

  6. Name this point P1.

  7. Take 2P distance in compass and mark it on the tangent from point 2. Name it point P2.

  8. Similarly, take 3 to P, 4 to P, 5 to P up to 7 to P distance in compass and mark on respective tangents and locate P3, P4, P5 up to P8.

  9. Join them in a smooth curve it is an involute of a given circle.


involute of circle string length more then piD

3 ] draw the involute of a circle. String length is less than the circumference of circle.

Solution Steps:

  1. In this case string length is less then πD.

  2. But remember whatever may be the length of string, mark πD distance horizontal i.e along the string and divide it in 8 number of equal parts, and not any other distance.

  3. Name after A 1, 2, 3, 4, etc up to 8 on πD line AP as well as on circle ( in anticlockwise direction).

  4. To radius C1, C2, C3 up to C8 draw tangents from 1, 2, 3, 4, etc to circle.

  5. Take distance 1 to P in compass and mark it on a tangent from point 1 on the circle.

  6. Name this point P1.

  7. Take 2P distance in compass and mark it on the tangent from point 2. Name it point P2.

  8. Similarly, take 3 to P, 4 to P, 5 to P up to 7 to P distance in compass and mark on respective tangents and locate P3, P4, P5 up to P8.

  9. Join them in a smooth curve it is an involute of a given circle.


involute of circle

 

Involute Of Composit Shaped Pole


1 ] A pole is of a shape of half hexagon and semicircle. A string is to be wound having equal to the pole perimeter, Draw the path of free end P of a string when would completely. ( take hex 30 mm sides and a semicircle of 60 mm diameter. )

Solution Steps:

  1. Draw pole shape as per dimensions.

  2. Divide semicircle in 4 parts and name those along with corners of hexagon.

  3. Calculate perimeter length.

  4. Show it as string AP. On this line mark 30 mm from 1 and dividing it into 4 parts names 2, 3, 4, 5.

  5. Mark point 6 on line 30 mm from 5. Now draw tangents from all points of a pole and proper lengths as done in all previous involute's problems and complete the curve.


  involute of circle string length more then piD

 
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