# Machine Kinematics Questions and Answers – Double Slider Crank Chain & its Inversions

This set of Machine Kinematics written test Questions & Answers focuses 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

Explanation: 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

Explanation: 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

Explanation: 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

Explanation: 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

Explanation: 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.
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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

Explanation: 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

Explanation: 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

Explanation: 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

Explanation: Oldham’s coupling is an instrument which is an inversion of double slider crank chain, this is used to connect two parallel shafts whose axes are at a small distance apart.

10. Which of the following link is fixed to obtain inversion in Oldham’s coupling?
a) Driving shaft
b) Flange
c) Supporting frame
d) Driven shaft

Explanation: The shafts are coupled in such a way that if one shaft rotates, the other shaft also rotates at the same speed. This inversion is obtained by fixing the link which corresponds to Supporting frame.

11. How many turning pairs are there in a double slider crank chain?
a) 1
b) 2
c) 3
d) 4

Explanation: Double slider crank chain is a kinematic chain which consists of two turning pairs, as a result it is called double slider crank chain.

12. A double slider crank chain has one pair of each sliding and turning pairs.
a) True
b) False

Explanation: In a double slider crank chain, there are two turning pairs and two sliding pairs. In a single slider crank chain there is one sliding pair and three turning pairs.

13. How many sliding pairs are there in a double slider crank chain?
a) 1
b) 2
c) 3
d) 4

Explanation: Double slider crank chain is a kinematic chain which consists of two sliding pairs, as a result it is called double slider crank chain.

14. In which of the following mechanisms inversion is obtained by fixing the cylinder?
a) Pendulum pump
b) Gnome engine
c) Double slider crank chain
d) Oscillating cylinder

Explanation: Pendulum pump also known as the bull engine is an inversion of single slider crank chain, here inversion is obtained by fixing the cylinder.

15. Which of the following is not an inversion of double slider crank chain?
a) Elliptical trammels
b) Scotch yoke mechanism
c) Oldham’s coupling
d) Gnome engine

Explanation: Gnome engine is an example of inversion of single slider crank chain, whereas Elliptical trammels, Scotch yoke mechanism and Oldham’s coupling are inversions of double slider crank chain.

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