Question

# Question 2. The reciprocating rectilinear motion mechanism, often referred to as a quick return mechanism since it can move much quickly in one direction than the other. As shown in Fig.

2, the mechanism consists of a disk pinned at its centre at A that rotates with a constant angular velocity AB, a slotted arm CD that is pinned at C, and a bar that can oscillate within the guides at E and F. As the disk rotates, the peg at B moves within the slotted arm, causing it to rock back and forth. As the arm rocks, it provides a slow advance and a quick return to the reciprocating bar due to the change in distance between C and B. To see this, we are interested to estimate the velocity of the bar in each of the two position shown (position 1 when B is farthest from C and position 2 when B is closest to C) under the assumption that the disk rotates at WAB = 150 rpm. For the positions 1 and 2 and d = 0.15 m, determine (a) the velocity of the bar when R/h = 0.35, (b) the velocity of the bar when R/h = 0.85, and (c) Discuss on which of the two R/h values would give a better quick return and why.