Tough Machine Kinematics Questions and Answers on “Single Slider Crank Chain and its Inversions – 2”.
1. A single slider crank chain is a _______
a) 4-link mechanism
b) 3-link mechanism
c) 2-link mechanism
d) 6-link mechanism
Answer: a
Clarification: A single slider crank chain is a four link mechanism, any four link mechanisms has 4 links inclusive of higher and lower pairs.
2. Bull engine is an inversion of single slider crank chain.
a) True
b) False
Answer: a
Clarification: In a bull engine the inversion is obtained by fixing the cylinder, thus it is an inversion of a single slider crank chain.
3. Find the ratio of the time of cutting to the time of return stroke from the following information: A crank and slotted lever mechanism used in a shaper has a centre distance of 0.300 m between the centre of oscillation of the slotted lever and the centre of rotation of the crank. The radius of the crank is 0.120 m.
a) 1.72
b) 1.65
c) 1.81
d) 1.79
Answer: a
Clarification: We know that time of cutting stroke to the time of return stroke is given by
360-α/ α
Using trigonometric ratios we find that α =132.8°
therefore, Ratio = 1.72.
4. Find the inclination of the slotted bar with the vertical in degrees in the extreme position from the following information: In a crank and slotted lever quick return motion mechanism, the distance between the fixed centres is 0.240 m and the length of the driving crank is 0.120 m.
a) 30
b) 45
c) 60
d) 75
Answer: a
Clarification: In a crank and slotted lever mechanism, symmetry can be observed. Using this symmetry and trigonometric ratios we find that
angle = 30 degrees.
5. Find the ratio of the time of cutting to the time of return stroke from the following information: In a crank and slotted lever quick return motion mechanism, the distance between the fixed centres is 0.240 m and the length of the driving crank is 0.120 m.
a) 3
b) 4.5
c) 3.2
d) 2
Answer: d
Clarification: In a crank and slotted lever mechanism, symmetry can be observed. Using this symmetry and trigonometric ratios we find that vertical inclination of slotted bar is
angle = 30 degrees.
now 90- α/2 = 30
α=120 degrees
therefore ratio = 2.
6. Find the length of stroke if the length of the slotted bar is 0.45m and LOS passes through the free end of the lever. Length of driving crank = 0.12m, distance between fixe centres = 0.24m. Crank and slotted lever quick return motion mechanism.
a) 450mm
b) 400mm
c) 500mm
d) 475mm
Answer: a
Clarification: We know that length of stroke is:
2x450xsin(90-α/2)
α=120 degrees,
therefore
length = 450mm.
7. Which of the following mechanism is mostly used in shaping and slotting machines?
a) Whitworth quick return motion mechanism
b) Bull engine
c) Crank and slotted lever quick return motion mechanism
d) Gnome engine
Answer: a
Clarification: Whitworth quick return motion mechanism is mostly used in shaping and slotting machines, as in this mechanism a turning pair is fixed and the driving crank rotates at a uniform speed.
8. In Whitworth quick return motion mechanism, the driving crank is under an accelerated motion
a) True
b) False
Answer: b
Clarification: In Whitworth quick return motion mechanism, the driving crank rotates at a uniform speed and is widely used in shaping and slotting machines.
9. Which of the following mechanism is used to convert reciprocating motion into rotary motion?
a) Whitworth quick return motion mechanism
b) Oscillating cylinder engine
c) Crank and slotted lever quick return motion mechanism
d) Gnome engine
Answer: a
Clarification: Oscillating cylinder engine is used to convert reciprocating motion into rotary motion, the piston reciprocates and the cylinder oscillates about the pin.
10. How many cylinders are there in Gnome engine?
a) 4
b) 5
c) 6
d) 7
Answer: d
Clarification: Rotary internal combustion engines were used in aviation. Now-a-days gas turbines are used in its place. It consists of seven cylinders in one plane and all revolves about fixed centre.
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