1. Case Study:
(1) The mechanism shown in the figure has been taken from a feed device for an automated ball
bearing assembly machine. An electric motor is attached to link A as shown. Carefully examine
the configuration of the components in the mechanism. Then answer the following leading
questions to gain insight into the operation of the mechanism.
a. As link A rotates clockwise 90 degrees, what will happen to slide C?
b. What happens to the ball trapped in slide C when it is at this position?
c. As link A continues another 90 degrees, clockwise, what action occurs?
d. What is the purpose of this device?
e. Why are there chamfers at the entry of slide C?
f. Why do you suppose there is a need for such a device?
(2) Consider the mechanism shown in the figure:
(a) What is the purpose of the device?
f
(b) What happens when link A is moved downward?
(c) What is the purpose of float D connected to link F?
(d) What will happen when the water level is at the mid level of the tank?
tank?
(e) Is there a tendency for the water to overflow?

2. Mechanism Design:
Design the following linkages in an A4 size paper, and using using a Sintra board (minimum size 17” x
11”) create a model of each linkages. Scale if necessary.
(1) Design a slider-crank (in-line) mechanism with stroke of 1.25 inches.
Note: to produce smooth acceleration: L3 >> L2.
(2) Design a slider-crank (offset) mechanism with a stroke of 2 inches.
Note: to produce smooth acceleration: L3 >> L2.
Rule of thumb L3 > 4L2
(3) Design a four bar mechanism with a throw (stroke) of 60 degrees θ4. The target frame length is 4
inches.
Hint: Often L1 has a target value. After construction, all dimensions can be scaled to
achieve the desired L1.
Rule of thumb 40o < γ < 140o, where γ is the transmission angle
Reference: Machines and Mechanisms Applied Kinematic Analysis by David Myszka© 1999 by Prentice
Hall, Inc.