Machine Kinematics written test Questions & Answers on “Double Slider Crank Chain & its Inversions”.
1. Which of the following instruments is used to draw ellipses?
a) Elliptical trammels
b) Slotted lever and crank
c) Gnome engine
d) Oldham’s coupling
Answer: a
Clarification: Elliptical trammel is an instrument which is an inversion of a double slider crank chain. It is mainly used to draw ellipses.
2. Elliptical trammels are used to convert reciprocating motion into rotary motion.
a) True
b) False
Answer: b
Clarification: Elliptical trammels are used to draw ellipses; scotch yoke mechanisms are used to convert rotary motion into reciprocating motion.
3. How inversion is obtained in an elliptical trammel?
a) Fixing the slotted plate
b) Fixing the sliders
c) Fixing the turning pairs
d) Fixing the pin
Answer: a
Clarification: An elliptical trammel is an instrument which is an inversion of a double slider crank chain, here the inversion is obtained by fixing the slotted plate. It is used to draw ellipses.
4. In the given figure, 1 and 2 are sliders, 3 is a bar and 4 is a fixed slotted plate, identify the mechanism.
a) Elliptical trammel
b) Scotch yoke mechanism
c) Oldham’s coupling
d) Gnome engine
Answer: a
Clarification: In the given figure, the slotted lever is fixed and there are two sliders, hence it is a double slider crank chain, since the slotted plate is fixed, it is an inversion. This inversion is known as elliptical trammels.
5. In the given figure if P is not the midpoint of the line connecting 1 and 2, what is the locus of P?
a) Ellipse
b) Straight line
c) Parabola
d) Rectangular hyperbola
Answer: a
Clarification: The given figure represents an elliptical trammel, in an elliptical trammel any point on the bar traces a path which is an ellipse, hence the locus of P is ellipse.
6. In the given figure if P is the midpoint of the line connecting 1 and 2, what is the locus of P?
a) Ellipse
b) Circle
c) Parabola
d) Rectangular hyperbola
Answer: b
Clarification: The given figure represents an elliptical trammel, in an elliptical trammel any point on the bar traces a path which is an ellipse, hence the locus of P is ellipse, but in this case P is the midpoint hence, the locus of P will be a circle.
7. Which of the mechanism is used to convert rotary motion into a reciprocating motion?
a) Elliptical trammel
b) Scotch yoke mechanism
c) Oldham’s coupling
d) Gnome engine
Answer: b
Clarification: Scotch yoke mechanism is an example of an inversion of a double slider crank chain, this mechanism is used to convert rotary motion into reciprocating motion.
8. In Scotch yoke mechanism, the crank is fixed in order to obtain the inversion.
a) True
b) False
Answer: b
Clarification: In scotch yoke mechanism there are in total 4 links, one is Crank and one is frame. Inversion can be obtained by fixing either of the remaining two links.
9. Which of the following mechanism is used for connecting two parallel shafts whose axes are at a small distance apart?
a) Elliptical trammel
b) Scotch yoke mechanism
c) Oldham’s coupling
d) Gnome engine