# EME2056−THEORY OF MACHINES

Question
As a machinery engineer, you are tasked to design a material handling mechanism that is able to slide 2 kg boxes along a counter (Figure 1). The mechanism is driven by a single motor and can be comprised of only linkages, gears, belt drives and/or cams. The mechanism needs to be mounted on the floor and/or side wall only. The coefficient of friction between the box and the counter is 0.20. The box size is 0.2 m × 0.2 m × 0.2 m.
(a) Explain the working principal of the mechanism and analyze its degree of freedom. Draw the mechanism according to scale. The position and dimension for all joints and links must be clearly shown. The trajectory of the linkage must be illustrated to show that the mechanism is functional and valid. If necessary, simulation can be performed using any CAD tool such as Linkage 3.0.
[26 marks]
(b) Apply the principles of relative velocity and relative acceleration to determine the velocity and acceleration of the link at the point of interest, A (the point where the link is in contact with the box). State the specification of the selected motor.
[30 marks]
(c) Determine all forces acting on the joints of all links and the torque required to drive the mechanism. The mass and center of gravity of all links must be stated (i.e. cannot be assumed as negligible). State any assumption made.
[40 marks]
(d) Determine furthest distance, x that the box can move. [4 marks]