1) Calculate the limiting speed to avoid cam jump, if an eccentric plate circular cam has eccentricity of 30 mm and provides motion to the follower of 4 kg mass. Stiffness of the spring is 30 N/mm2. Preload in the spring is 600 N
a. 70.81 rad/sec
b. 60.76 rad/sec
c. 141.42 rad/sec
d. None of the above
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Answer
Explanation
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ANSWER: 141.42 rad/sec
Explanation:
No explanation is available for this question!
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2) Which motion of follower is best for high speed cams?
a. SHM follower motion
b. Uniform acceleration and retardation of follower motion
c. Cycloidal motion follower
d. All of the above
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Answer
Explanation
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ANSWER: Cycloidal motion follower
Explanation:
No explanation is available for this question!
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3) Which of the following statements is false for SHM follower motion?
a. SHM can be used only for moderate speed purpose
b. The acceleration is zero at the beginning and the end of each stroke
c. The jerk is maximum at the mid of each stroke
d. Velocity of follower is maximum at the mid of each stroke
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Answer
Explanation
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ANSWER: The acceleration is zero at the beginning and the end of each stroke
Explanation:
No explanation is available for this question!
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4) Which of the following conditions can be used to minimize undercutting in cam and follower mechanism?
a. By using larger roller diameter
b. By using internal cams
c. By decreasing the size of the cam
d. All of the above
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Answer
Explanation
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ANSWER: By using internal cams
Explanation:
No explanation is available for this question!
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5) Which of the following equation is used to measure pressure angle between direction of follower motion and force exerted by the cam on follower when eccentricity is zero?
Where,
rb = base circle radius
y = displacement of follower
a. cot Φ = (dy /dθ) / ( r b + y)
b. tan Φ = (dy /dθ) / ( r b + y)
c. tan Φ = (dy /dθ) x ( r b + y)
d. cot Φ = (dy /dθ) x ( r b + y)
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Answer
Explanation
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ANSWER: tan Φ = (dy /dθ) / ( rb + y)
Explanation:
No explanation is available for this question!
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6) To avoid jump phenomenon, which of the following condition should be true?
Where,
P = preload in spring, ω = cam speed, k = stiffness of spring, e = eccentricity
a. ω > √ (me) / ( P + 2 ke)
b. ω > √( P + 2 ke) / (me)
c. ω < √( P + 2 ke) / (me)
d. ω < √ (me) / ( P + 2 ke)
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Answer
Explanation
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ANSWER: ω < √( P + 2 ke) / (me)
Explanation:
No explanation is available for this question!
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7) What is meant by jump phenomenon in cam and follower system?
a. Follower looses contact with cam surface when cam rotates beyond particular speed due to inertia forces
b. Follower looses contact with cam surface when follower rotates beyond particular speed due to gravitational force
c. Follower looses contact with cam surface when cam rotates beyond particular speed due to gravitational forces
d. None of the above
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Answer
Explanation
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ANSWER: Follower looses contact with cam surface when cam rotates beyond particular speed due to inertia forces
Explanation:
No explanation is available for this question!
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8) A cam operating roller follower has the following dimensions, radius of base and nose circle as 15 mm and 10 mm respectively and distance between them is 8 mm. Determine lift made by the follower
a. 5 mm
b. 12.5 mm
c. 3 mm
d. 17 mm
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Answer
Explanation
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ANSWER: 3 mm
Explanation:
No explanation is available for this question!
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9) Which of the following statements is/are true for cam profile?
a. Pitch point on the pitch curve has minimum pressure angle
b. In case of roller follower, trace point represents centre of the roller
c. Pitch circle is drawn through trace point from the center of cam
d. All of the above
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Answer
Explanation
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ANSWER: In case of roller follower, trace point represents centre of the roller
Explanation:
No explanation is available for this question!
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10) Which type of cam does not require any external force to have contact between cam and follower?
a. Preloaded spring cam
b. Conjugate cam
c. Both a. and b.
d. None of the above
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Answer
Explanation
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ANSWER: Conjugate cam
Explanation:
No explanation is available for this question!
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