Understanding the Single Slider Crank Mechanism and its Inversions

A single slider crank mechanism is a four-link kinematic chain where one link is a sliding pair (prismatic joint) and the other three links are turning pairs (revolute joints). It is a fundamental mechanism used in many engines and pumps.

The four links in a standard single slider crank mechanism are:

• Link 1: Frame (usually fixed)
• Link 2: Crank (rotates about a fixed pivot)
• Link 3: Connecting Rod (connects crank and slider)
• Link 4: Slider (slides along a fixed path)

The pairs are:

• Revolute pair between Link 1 and Link 2.
• Revolute pair between Link 2 and Link 3.
• Revolute pair between Link 3 and Link 4.
• Sliding pair between Link 4 and Link 1.

Mechanism Inversions by Fixing the Sliding Pair Link

Inversions of a kinematic chain are obtained by fixing a different link in the chain. The question asks about fixing the "sliding pair". The sliding pair is between Link 4 (the slider) and Link 1 (the frame). While fixing the pair itself doesn't create an inversion, the question likely refers to fixing the link associated with the sliding motion, which is the slider (Link 4).

When Link 4 (the slider) is fixed, the resulting mechanism is known as the Bull engine mechanism or Pendulum pump mechanism.

Let's look at the inversions of the single slider crank mechanism based on which link is fixed:

Analyzing the Options

Based on the inversions:

• Bull engine: This is obtained when the slider link (Link 4) is fixed. This matches the scenario described where the link associated with the sliding pair is fixed.
• Oscillating cylinder engine: This is obtained when the connecting rod (Link 3) is fixed.
• Gnome engine: This is a type of internal combustion engine with a rotating cylinder block, not a direct inversion of a standard single slider crank mechanism.
• Crank and slotted lever quick return mechanism: This is an inversion of a four-bar chain with one sliding pair, specifically related to the Whitworth mechanism but a different configuration, often used for shaping machines. It is not an inversion of the standard single slider crank mechanism where the slider is fixed.

Therefore, the mechanism obtained by fixing the link associated with the sliding pair (the slider) in a single slider crank mechanism is the Bull engine.