Chapter 8, Problem 8.1P

Programs DYNACAM and MATRIX may be used to solve these problems or to check your solution where appropriate.

Figure P8-1 shows the cam and follower from Problem 6-65. Using graphical methods, find and sketch the equivalent fourbar linkage for this position of the cam and follower.

To determine

To sketch: The equivalent four bar linkage of thecam follower.

Explanation of Solution

Cams are rotated by cam pair at A and B. For an equivalent four bar linkage of cam and follower mechanism, the cam pair is converted into two turning pair by an imaginary link AB. Length of the link will be equal to the center of curvature distances between two cams. Also the two cam is replaced by a two links O₂A and O₂B. O₂A is the distance between center of curvature of left cam at A and center of rotation of left cam at O₂. Similarly O₂B is distance between the center of curvature of right cam at B and center of rotation of right cam at O₄.

Graphical method for four bar mechanism:-

1. Take O₂ and O₄ as a fix link.
2. Mark A and B as a center of curvature of the left and right cam respectively.
3. Draw O₂A and O₂B and join A and B as AB.

Drawing the equivalent four bar linkage as shown below:

O₂ABO₄is the equivalent 4 bar linkage of two sliding cam mechanism. The angular velocity of left and right cam will be equal to the angular velocity of link O₂A and O₂B respectively.