KINEMATICS OF MACHINERY Model Paper's Alternate link

SKYUP'S MEDIA KOM Model Paper's

MODEL PAPER –1

SUB : KINEMATICS OF MACHINERY

PART- A

1. Answer the following questions.

(i) Write the

grashoff’s

law for a four bar mechanism

(ii)

What is a configuration diagram ? Where it can be use.

(iii)

Define Rubbing velocity. what will be the expression for rubbing velocity at a pin joint when the

two links rotate in opposite direction.

(iv)

State the expressions for maximum acceleration of a follower moving in a cycloidal

motion.

(v)

Why some times the axes of translating roller followers in cam follower mech nisms are

offset

from the axis of rotation of cam?

(vi) Define the term ‘ arc of contact ‘ in gears .

(vii) Name two applications of reverted gear train.

(viii)Why self locking screws have lesser efficiency ?

(ix)What is meant by self locking and self energized brake?

(x).What is Degrees of freedom .write the expression for degrees of fr  dom for planner

e

mechanism.

PART- B

2. (a) Sketch and explain the four inversions of a single lider crank chain .

(or)

'

(b) (i) What are straight-line mechanisms ? Sketch the Peaucellier straight-line motion mechanism

and prove that generating point movesin a straight line.

(ii) Sketch the hook’s joint and derive the condition for equal speeds of

driving and driven shafts.

3. (a) In a four bar chain ABCD ,AD is fixed and is 120 mm long. The crank AB is 30 mm long and rotates

at 100 rpm clockwise while the link CD = 60mm oscillates about D; BC = 120 mm .using graphical

y

0 .

method, find the angular velocity and angular acceleration of link BC whan angle BAD = 60

Or

(b) (i) Derive the expressions for the velocity and acceleration of the piston of a reciprocating engine

Mechanism.

(ii) In a reciprocating engine mechanism, the lengths of the crank and connecting rod are 150 mm and 600 mm respectively . The crank position is 60⁰ from inner dead centre. The crank shaft speed is 450 r.p.m.(clockwise).Using analytical method , determine

(1)    Velocity of the piston

(2)     Acceleration of the piston

(3)     Crank angle for maximum velocity of the piston and the corresponding velocity.

4.  (a) A cam with a minimum radius of 25 mm, rotating clockwise at a uniform speed is to be designed to give motion to a roller follower, at the end of a cam valve rod, as described below :

(i)   To raise the valve through 50 mm during 120⁰ rotation of the cam.

(ii)   To keep the valve fully raised through next 30⁰ .

(iii)    To lower the valve during next 60⁰ and

(iv)   To keep the valve closed during rest of the revolution.

The diameter of the roller is 20 mm and the diameter of the cam shaft is 25 mm. The line of the stroke is offset by 15 mm from the axis of the cam shaft. The displacement of the valve , while being raised and lowered is to take place with SHM.

(1)	Draw the displacement diagram. Sketch roughly the shapes of velocity and acceleration diagrams.
(2)	Draw the profile of the cam .	(10M)
	(or)

(b)   In a symmetrical tangent cam operating a roller follower , the least radius of the cam is 30 mm and roller radius is 17.5 mm. The angle of ascent is 75⁰ and the total lift is 17.5 mm. The speed of

the cam shaft is 600 rpm.Assume that there is no dwell between ascent and descent.

(i)   Calculate the principal dimensions of the cam .

(ii)   Find the acceleration of the follower at the beginning of the lift.

(iii) Draw the profile of the cam.

(10M)

5.  (a) (i) State and prove the law of gearing .

(ii)   Show that the involute curves as the profiles of mating gears satisfy the law of gearing. (10M)

Or

(b) A compound gear train using spur gears is required to give a total reduction ratio of 250 to 1 in four steps. The modules of the gears are 5 mm for the first step 7 mm for the second , 10 mm for the third and 16 mm for the fourth.

(i) Arrive at the individual speed ratios, if a tolerance of + 0.2 % is allowed in the total reduction ratio.

(ii) Find the numbers of teeth of all gears, if the minimum number of teeth for  ny pinion is 20.

(iii) Find the pitch circle diameters of all gears and the centre distances.

(iv) Sketch a line diagram showing the gear train.                                                                        (10M)

6. (a) In a thrust bearing , the external and internal diameters of the contacting surfaces are 320 mm

and 200 mm respectively. The total axial load is 80 KN and the int nsity of pressure is 350 KN/m².

The shaft rotates at 400 rpm. Taking the coefficient of friction as 0.06,calculate the power lost in

overcoming yhe friction and the number of collars reqired.                                                        (10M)

Or

(b) Derive an expression for the centrifugal tension in a belt passing round a pulley rim.                          (10M)

ENGINEERING

SKYUP'S MEDIA KOM Model Paper's

MODEL PAPER –2

: KINEMATICS OF MACHINERY

	PART- A
1. Answer the following questions.
i.	Define degree of freedom (or) what is mean by mobility?	(2M)
ii.	How to determine the given assemblies of links forms the kinamatic chain or not?	(3M)
iii.	What is pantograph?	(2M)
iv.	What is the magnitude of linear velocity of a point B on a link AB relative to A?	(3M)
v.	What is the expression for coriolis component of acceleration?	(2M)
vi.	What is a cam?	(2M)
vii.	Give some examples for cams	(3M)
viii.	What are the standard interchangeable tooth profiles.	(2M)
ix.	What are the methods to avoid interference?	(3M)
x.	What is the efficiency of inclined plane ?	(2M)

PART- B

2.  a) Explain any two inversion of four bar chain.

b)  Explain the first inversion of Single Slider Crank Chain.

3.              a)Derive the expressions for Velocity and acceleration of piston in reciprocating steam engine mechanism with neat sketch

or

b)  Derive the expression for Coriolis com onent of acceleration with neat sketch

4.                   A cam, with a minimum radius of 50 mm, rotating clockwise at a uniform speed, is required to giver a knife-edged follower the motion as described below: (a) To move outwards through 40 mm during 100° rotation of the cam; (b) to dwell for next 80° (c) To ret rn to its starting position during next 90 ° and (d) To dwell for the rest period of revolution. Draw the profile of the cam (i) When the line of stroke of the follower passes through the centre of the cam shaft and (ii) When the line of stroke of the follower is to take place with Uniform acceleration and uniform retardation. Determine the maximum velocity and acceleration of the follower when the cam shaft rotates at 900 r.p.m. (15)

or

(b)  Two mating spur gear with module pitch of 6.5 mm have 19 ad 47 teeth of 20°pressure angle and 6.5 mm addendum. Determine the number of pair of teeth and angle turned through by the larger wheel for one pair of teeth in contact. Determine also the sliding velocity at the instant (i) engagement commences (ii) engagement terminates. When the pitch line velocity is 1.2 m/s.

5.                    a) The number of teeth on each of the two spur gears in mesh is 40. The teeth have 20°involute profile and the module is 6mm. If the arc of contact is 1.75 times the circular pitch. Find the

addendum.

or

b). The mean diameter of the screw jack having pitch of 10 mm is 50 mm. A load of 20 KN is lifted through a distance of 170 mm. Find the work done in lifting the load and efficiency of the screw jack when (i) the load rotates with the screw, and (ii) the load rests on the loose head which does not rotate with screw. The external and internal diameter of the bearing surface of the loose head is 60 mm and 10mm respectively. The coefficient of friction for the screw as well as the bearing surface may be taken as 0.08.

SKYUP'S MEDIA KOM Model Paper

MODEL PAPER –3

SUB : KINEMATICS OF MACHINERY

PART- A

1. Answer the following questions.

i.	Compare machine and structure?	(2M)
ii.	Give some examples for kinamatic pairs.	(3M)
iii.	Discuss ‘Elliptical trammel’.	(2M)
iv.	What is meant by the efficiency of a mechanism?	(3M)

v.            How to represent the direction of linear velocity of any point on a link with respect to another

	point on the same link?	(2M)
vi.	How can you prevent undercutting in cam ?	(3M)

vii.             What do you know about gravity cam?

viii.	What are the standard interchangeable tooth profiles.	(2M)
ix.	What are the methods to avoid interference?	(3M)
x.	What is the efficiency of inclined plane ?	(2M)
xi.

PART B

2.       a)With the help of a neat sketch explain the working of Oldham’s coupling.

or

b)  ) Explain steering gear mechanism with neat sketch

3.       In a slider crank mechanism, the length of the crank and the connecting rod are 100 mm and 400 mm respectively./ The crank [position is 45°from IDC, the crank shaft speed is 600 r.p.m. clockwise. Using analytical method Determine

(1)Velocity and acceleration of the slider, and

(2) Angular velocity and angular acceleration of the connecting rod.

or

(b) Locate all instantaneous centers of the slider crank mechanism; the length of crank OB and Connecting rod AB are 125 mm and 500 mm respectively. The crank speed is 600 rpm clockwise. When the crank has turned 45°from the IDC. Determine (i)velocity of

.           slider’ A’ (ii)Angular  Velocity of connecting rod ‘AB’.

4. (a) Draw the profile of a cam operating a roller reciprocating follower and with the following data: Minimum radius of cam =25 mm; lift=30mm; Roller diameter= 15mm. The cam lifts the follower for 120°with SHM, followed by a dwell period of 30°. Then the follower lowers down during 150°of cam rotation with uniform acceleration and retardation followed by a dwell period. If the cam rotates at a uniform speed of 150 RPM. Calculate the maximum velocity

and acceleration of follower during the descent period.

Or

(b)     In a reverted epicyclic train, the arm F carries two wheels A and D and a compound wheel B-C. Wheel A meshes with wheel B and Wheel D meshes with wheel C. Ther number of teeth on wheel A, D and C are 80, 48, and 72. Find the speed and direction of wheel D , when wheel A is

fixed and arm F makes 200 rpm clockwise.

5.a) A multiplate disc clutch transmits 55 KW of power at 1800 rpm. Coefficient of friction for the friction surfaces is 0.1. Axial intensity at pressure is not to exceed 160 KN/m². The internal radius is 80 mm and is 0.7 times the external radius. Find the number of plates needed to transmit the required torque.

or

b) A rope drive is required to transmit 230 KW from a pulley of 1m diameter running at 450 rpm. The safe pull in each rope is 800 N and the mass of the rope is 0.4 kg per meter length. The angle of lap and groove angle 160⁰ and 45⁰ respectively. If coefficient of friction is 0.3, find the number of ropes

required.

(8)

SKYUP'S MEDIA KOM Model Paper

SUB : KINEMATICS OF MACHINERY

	PART- A
1. Answer the following questions.
i.	What are the disadvantage of V-belt drive over flat belt ?	(2M)
ii.	What is the condition of transmission of optimum or maximum power in belt drive?	(3M)
iii.	List out the commonly used breaks.	(2M)
iv.	Define cycloidal tooth profile and involute tooth profile.	(3M)
v.	Define circular pitch and diametral pitch in spur gears.	(2M)
vi.	Define Backlash.	(3M)
vii.	Define pressure angle with respect to cams.	(2M)
viii.	Define undercutting in cam. How it occurs?	(3M)
ix.	Define Lift (or) Stroke in cam.	(2M)
X	Write down the grashof’s law for four bar mechanism.	(3M)

PART B

2. a).A leather belt is required to transmit 7.5 kw from a pulley 1.2 m in diameter, running at 250 rpm. The angle entranced is
1650 and the coefficient of friction between the belt6 and the pulley is 0.3. If  safe working stress for the leather belt is 1.5
MPa, density of leather is 1 kg/ m3	end thickness of belt is 10 mm. Determine the width of the belt taking C.F tension into

account.

or

b).Two pulley one 450 mm diameter and other 200mm dia are on parallel shaft 2.1 m apart and are connected by a cross belt. The larger p lley rotates at 225 rpm. The maximum permissible tension in the belt is 1 KN and the coefficient of friction between the belt and the pulley is 0.25. Find the length of the belt required and the power can be transmitted.

3. An epicyclic train is composed of a fixed annular wheel A having 150 teeth. Meshing with A is a wheel B which drives wheel D through an idle wheel C, D being concentric with A. Wheels B and C are carried on arm which revolves clockwise at 100 rpm about the axis of A or D. If the wheels

B and D are having 25 teeth and 40 teeth respectively, find the number of teeth of C and the speed and sense of rotation of C.

Or

b) The sun planet gear of an epicyclic gear train, the annular D has 100 internal teeth, the sun gear A has 50 external teeth and planet gear B has 25 external teeth. The gear B meshes with gear D and gear A. The gear B is carried on arm E, which rotates about the centre of annular gear D. If

the gear D is fixed and arm rotates at 20 rpm, then find the speeds of gear A and B.

4. a) Draw the profile of a cam operating a Knife -edged follower from the following data: (a) Follower to move outward through 40 mm during 60° of a cam rotation; (b) Follower to dwell for the next 45°

(c) Follower to return its original position during next 90° (d)Follower to dwell for the rest of cam rotation. The displacement of the follower is to take place with simple harmonic motion during both the outward and return strokes. The least radius of the cam is 50mm. If the cam rotates at 300 r.p.m., determine the maximum velocity and acceleration of the follower during the outward stroke

and return stroke.

or

(b)     In a slider crank mechanism, the length of the crank and the connecting rod are 100 mm and 400 mm respectively./ The crank [position is 45°from IDC, the crank shaft speed is 600 r.p.m. clockwise. Using analytical method Determine

(1)Velocity and acceleration of the slider, and

(3)    Angular velocity and angular acceleration of the connecting rod.(15)

5.       Draw the profile of a cam operating a roller reciprocating follower and with the following data: Minimum radius of cam =25 mm; lift=30mm; Roller diameter= 15mm. The cam lifts the follower for 120°with SHM, followed by a dwell period of 30°. Then the follower lowers down during 150°of cam rotation with uniform acceleration and retardation followed by a dwell period. If the cam rotates at a uniform speed of 150 RPM. Calculate the maximum velocity and acceleration of follower during the descent period.

Or

b) It is required to set out the profile of a cam to give the following motion to the reciprocating follower with a flat mushroom contact surface: (i) Follower to have a stroke of 20 mm during 120°of cam rotation, (ii) Follower to dwell for 30° of cam rotation, (iii) Follower to return to its initial position during 120° of cam rotation, (iv) Follower to dwell for remaining 90° of cam rotation. The minimum radius of the cam is 25 mm. The out stroke of the follower is performed with SHM and return stroke

with equal uniform acceleration and retardation.