ME 35 / Kinematics of machinery

THE INDIAN ENGINEERING COLLEGE

DEPARTMENT OF MECHANICAL ENGINEERING

 I Series test (Aug 2011)

ME 35 / Kinematics of machinery

Date: 10-08-2011                                                                                              Maximum Marks: 50

Year/Sem: II / III                                                                                          Time: 9.30am – 11.30am

Answer ALL questions

PART – A (5x2=10 marks)

1. What is cam profile?

2. Write the types of follower according to the follower shape.

3. What is law of gearing?

4. What is velocity ratio?

5. What is pitch circle diameter?

PART - B

PART – B (4x10=40 marks)

1. A cam is to give the following motion to a knife edge follower.                                       (14)

            a) It lifts the follower through 37.5 mm during its 60^o rotation with SHM

            b) The follower remains at rest for the next 40^o rotation of the cam

            c) The follower then descends to its original during 90^o rotation of the cam with SHM

            d) The follower remains at rest for the rest of the rotation.

            Draw the profile of the cam when the line of stroke is offset by 20mm from the axis of the cam shaft. The least radius of the cam is 50mm.

2. From the following data, draw the profile of the cam in which the follower moves with SHM during ascent while it moves with uniformly accelerated motion during descent:                       (13)      a) Least radius of cam                        = 50mm

            b) Angle of ascent                   = 48^o

            c) Angle of dwell between ascent and descent          = 42^o

            d) Angle of descent                 = 60^o

            e) Lift of follower                    = 40mm

            f) Diameter of roller               = 30mm

If cam rotates at 360 rpm anticlockwise, find the maximum velocity and acceleration of the follower during descent.

3. A pinion having 20 teeth engages with an internal gear having 80 teeth. If the gears have involutes profiled teeth with 20^o pressure angle, module of 10mm and addendum of 10mm, find the path of contact, arc of contact and the contact ratio.                                     (8)

4. A toothed gear A is to drive another gear B. The centre to centre distance between their axes of rotation is to be exactly 375 mm. Speed of A is to be 500rpm and that of B is 350rpm

approximately. If each gear is of module 5mm, determine what should be the number of teeth on each gear.