Question

3.40 ft Design a mechanism that receives gift boxes at position A,B1 and moves them to position A2B2 and then to position A3B3, and then returns to receive the next gift box at position A,B1 The mechanism will grab the boxes at points A and B at the two rings attached to the sides of the boxes a) 2.31 ft 0.17 ft 2.13 f 0.8 ft b) Add a driver dyad with a quick return ratio of 1.2, i.e. the mechanism should take 20% more time in going from A,B1 to A2B2 to A3B3 than in the return path from A3B3 to AB c) Measure and report all the link lengths d) Calculate the extreme values of the transmission angles for 59.55 the driver dyad

Answer 1

Steps:

1) Draw the figure the scale and join the positions of the corresponding path of given points. (i.e. A1-A2, A2-A3, B1-B2,B2-B3)

2) Draw the perpendicular bisectors for the above mentioned segments.

3) The intersection of the bisectors for path of A is O1 and that for B is O2.

4) Now join O1A1 and O2A3. and draw the angular bisector.

5) take any point on this bisector and draw an angle of 90-alpha/2 wrt the bisector in the downward sense.

6) Use the point of intersection of the above line and the O1A1 line and draw a perpendicular to O1A1.

7) Taking the centeras the intersection of the above perpendicular with the angle bisector and radius equal to the length O3L is the crank for the dyad.

sorry for a small mistake in the figure. The L point should be a slider.