06 ME 44 USN IV Sem B E Examination

KINEMATICS OF MACHINES [ Common to ME / IP / IM / AU / MA ] MODEL QUESTION PAPER Time: 3 Hrs.]

[Max. Marks: 100 (Answer any FIVE questions selecting atleast two from each part)

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PART-A a) Sketch and briefly explain the following: i) Crank lever mechanism ii) Scotch yoke mechanism iii) Oscillating cylinder mechanism iv) Spherical pair b) What is a machine ? Differentiate between a machine & a mechanism.

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a) Sketch the Ackermann steering mechanism and explain its applications and limitations. b) Explain briefly with neat sketchs the working of i) Toggle mechanism ii) Ratchet and Pawl intermittent motion mechanism ?

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a) What is Corrolis component of acceleration ? Derive an expression for the same. b) Determine the velocity of point K in the mechanism shown in Fig.2

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a) Locate all the instantaneous centers for a 10 i) slider crank mechanism. ii) Four bar mechanism. b) In the mechanism shown in Fig.3., crank 2 rotates at 3000rpm. Find the acceleration of the point C in magnitude, direction and sense. Find also the acceleration of link 4 slider. 10

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PART- B A four bar mechanism ABCD has links AB, BC, CD & AD measuring 60mm, 80mm and 120mm long respectively. At a certain instant AB makes 60 with AD, the fixed link, if AB rotates at 10 rpm clockwise determine analytically 10+10 i) Angular vel of links BC & CD ii) Angular acceleration of BC & CD. a) Write a note on : i) Involutiometry ii) Helical gearing 06 b) The following data refers to two mating involute gears of 20o pressure angle. Number of teeth on the pinion is 20, gear ration = 2, speed of the pinion is 250rpm, module 12mm. If the addendum on each wheel is such that the path of approach and the path of recess on each side are half of the maximum permissible length. Find the maximum velocity of sliding during approach and recess and the length of arc of contact. 14 a) Enumerate the limitations of 06 i) Simple gear trains ii) Compound gear trains iii) Riverted gear trains. b) In the epicyclic gear train shown in Fig.4.0 wheels A, D, E are free to rotate independently on the spindle P on arm OP. If wheel A is given clockwise rotation of 60rpm, while gear D is driven counter clockwise at 300rpm, determine the magnitude and direction of speeds of arm OP and wheel E. 14 a) Give a classification of cams and followers. b) Draw the profile of the cam for the following details. Minimum radius of the cam : 20MM; Rotation : CCW, 1000rpm Follower : 10mm diameter roller; Lift of the follower : 20mm Outward stroke : Uniform acceleration and retardation during 120o o Dwell at full life : 60 Return stroke : SHM during 120o Offset-Follower axis 5mm to the right of the axis of cam. Calculate maximum acceleration during return stroke.

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MODEL QUESTION PAPER FOURTH SEMESTER B E EXAMINATION KINEMATICS OF MACHINES (COMMON TO AU/ME/IP/IM/MA) Sub Code: 06 ME 44 Max. Marks:100 Note: 1. Answer any FIVE FULL questions, selecting at least TWO from each parts. 1. Graphical solutions are to be drawn only in the answer book or in the GRAPH sheets selecting suitable scale if required. 2. Missing data if any may be suitably assumed. PART A 1. a. Define with suitable examples: i) Kinematic pair ii) Mechanism

iii) Degree of freedom

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b. Explain with the help of neat sketches the following mechanisms: i) Double Rocker mechanism ii) Oscillating cylinder engine mechanism iii) Parallel crank mechanism (14) 2. With the help of neat sketches explain the working principle of a) Peaucellier’s mechanism. (10) b) Crank and slotted lever mechanism

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and also state their applications 3. In a slider crank mechanism the lengths of the crank and connecting rod are 125 and 500 mm respectively. The center of gravity G of the connecting rod is 275 mm from the slider. The crank speed is 600 rpm clock wise. The crank makes 45° from IDC clock wise. For the position given determine i) velocity of the slider, point G and angular velocity of the connecting rod. ii) The acceleration of the slider and point G. (20) 4 .a. In a four bar mechanism having link lengths AB = 300 mm, BC = 350, CD = 300 mm and AD = 600 mm. Angle BAD is 60°. The crank rotates uniformly at 100 rpm. Locate all the instantaneous centers and find the angular velocity of the link BC. (10) b. The crank of a reciprocating engine is 200 mm long and the connecting rod is 800 mm. the crank rotates at 480 rpm. Find the velocity and acceleration of the piston using Klein’s construction method when the crank is at 45° from inner dead center. (10).

PART B 5.In a four bar mechanism ABCD, AD is the fixed link and 100 mm long, AB = 50 mm, CD = 60 mm, angle BAD = 60°, angle ADC = 80°. The crank AB is driven at 10.5 rads/ sec in CCW direction. Find the angular velocity and acceleration of the link BC and CD using complex algebra method. (20) 6. a. state and prove the Law of gearing.

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b. the following data refers to two involute gears of 20° pressure angle. Number of teeth on the pinion is 20 gear ratio is 2, speed of the pinion is 4 rps, module 6 mm. if the addendum is such that path of recess on each side is half the maximum length. Determine: i) The addendum height for each gear wheel. ii) Length of arc of contact. iii) Maximum velocity of sliding during approach and recess. (14) 7. An epicyclic gear train consists of a SUN wheel S, a stationary internal wheel E and three identical planet wheels P carried on a star shaped planet carrier C. the sizes of the wheel are such that the planet rotates at 1/5th of the rotation of the speed of the sun wheel. The minimum number of teeth on any wheel is 16. the driving torque on the SUN wheel is 100 N-m. Determine: i) Number of teeth on the wheels. ii) Torque necessary to keep the internal gear stationary. (20) 8. A flat faced follower is raised through a distance of 25 mm in 120° of cam rotation, remains at rest for the next 30° and is lowered further during 120° of cam rotation. The raise of the follower takes place with SAM where as the fall occurs with SHM. The least radius of the cam is 25 mm. Draw the cam profile assuming clockwise rotation. (20)

06 ME 44 USN IV Sem B E Examination

KINEMATICS OF MACHINES [ Common to ME / IP / IM / AU / MA ]

MODEL QUESTION PAPER Time: 3 Hrs.]

[Max. Marks: 100 (Answer any FIVE questions selecting atleast two from each part) Note: 1. Answer any FIVE FULL questions, selecting atleast TWO from each parts. 2. Graphical solutions are to be drawn only in the answer book or in the GRAPH sheets selecting suitable scale if required. 3. Missing data if any may be suitably assumed.

3.

PART A a. Define with suitable examples: i) Lower pair ii) Inversion iii) Kinematic Chain. b.Explain with the help of neat sketches the inversions of Double slider crank

(06) chain.

(14) 2. a. With the help of neat sketches explain the working principle of Pantograph, and also state the applications. (10) b. Derive the condition for the correct steering mechanism. (10) 3. In a four bar mechanism the crank AB rotates at 36 rads/sec the lengths of the links are AB = 200 mm, BC = 400 mm, CD = 450 mm, and AD = 600 mm. AD is a fixed link. At the instant when AB is at right angle to AD determine the velocity of i) the mid point of link BC, ii) A point on link CD, 10 mm from the pin connecting the links CD and AD. (20) 4. a. In a four bar chain the crank AB rotates uniformly at 100 rpm. The link lengths are AB = 150 mm, BC = 180 mm, CD =180 mm, and AD = 300 mm. AD is the frame. At the instant when the link AB makes and angle of 60° with the link AD, determine the angular velocity of link BC by Instantaneous Centers method. (10) b. the crank of a reciprocating engine is 60 mm long and the connecting rod is 240 mm. the crank rotates at 400 rpm. Find the velocity and acceleration of the piston using Klein’s construction method when the crank is at 30° from inner dead center. (10) PART B

5. Using complex algebra method derive the expressions for the velocity and acceleration of the piston, angular acceleration of the connecting rod of a reciprocating engine mechanism. With this expressions determine the above quantities if the crank length is 50 mm, connecting rod is 200 mm, the crank speed is constant at 3000 rpm and the crank angle is 30°. (20) 6. a)Derive an expression for the minimum number of teeth on the gear wheel meshing with the pinion of involute profile to avoid interference. (08) b). Determine the length of path of contact, arc of contact and the contact ratio when the pinion having 17 teeth drives a gear having 51 teeth. The profile of the gear is involute with a pressure angle of 20° and module of 4 mm. (12) 7. An internal wheel B with 80 teeth is keyed to a shaft F. a fixed internal wheel C with 82 teeth is concentric with B. a compound wheel D-E gears with the two internal wheels. D has 28 teeth and gears with C while E gears with B. the compound wheels revolve freely on a pin which projects from the disc keyed to shaft A coaxial with F. if the wheels have the same pitch and the shaft A makes 800 rpm, what is the speed of shaft F. (20) 8. Draw the profile of the cam for the following details. Minimum radius of the Cam = 20 mm Rotation = 1000 rpm ccw. Follower = 10 mm dia. Roller. Lift = 20 mm Out stroke = UARM during 120° Return stroke = SHM during 120° Dwell in between rise and fall = 60° Offset of the follower = 5 mm to the right.

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