Kinematics - Resolution and Composition (Plate #2)

 My second plate is about Velocity Analysis using the resolution and composition method. Velocity analysis is a graphical technique used for the determination of the velocities of the parts of a mechanical device, specially those of a plane mechanism with rigid component links. It was the first lesson on my Kinematics class and my third plate is also about velocity analysis using the instantaneous axis method.

The drawing itself is not that hard but you need to be very careful in executing the steps. Analyzing the problem is much more difficult. The more complex the linkage are the harder it will be. My second plate isn't that complicated but it took me about 3 hours just to finish this plate and I hope I will get a high grade on it. 

Drawing after the cut.

Here's my second plate.

Q2BBCQ4EFPS is a compound linkage. Q2 and Q4 are fixed centers on a horizontal line with Q4 7.5 inches to the right of Q2. Q2B, 3.5 inches long, oscillates above Q2. CQ4 is a crank 2 inches long that rotates about Q4. BC is a connecting rod 7 inches long. P is an oscillating bearing block that is pivoted at a fixed point 4.5 inches above Q4. EF, 8.5 inches long, which is pinned to the mid point of the connecting rod BC at E, extends through the oscillating block at P. F is connected to a slide 7 by a link FS, 6.5 inches long. The slide 8 moves in a vertical guide whose center line is 1.5 inches to the right of Q4. Q4C rotates uniformly counterclockwise at 30 rpm and has turned through an angle of 150 degrees from right horizontal position, causing S to be below Q2Q4. 

The problem was retrieved from Elements of Mechanism by Doughtie and James, p.471 - L-8.