Summary of previous lecture

• Degrees of freedom• Gruebler’s Criterion• Grashof’s four-bar mechanism• Kinematic Inversions• Types of Kinematic Chains

Today’s lecture

• Few Videos on various mechanisms

• Kinematic Inversions

•Inversions of Four Bar Chain•Inversions of Single Slider Crank Chain•Inversions of Double Slider Crank Chain

Types of Kinematic Chains

• Four bar chain

• Single slider crank chain• Double slider crank chain

Inversions of Four Bar Chain

• Beam engine (crank and lever mechanism)• Coupling rod of a locomotive (Double crank mechanism)• Watt’s indicator mechanism (Double lever mechanism)

The purpose of this mechanismis to convert rotary motion intoreciprocating motion.

Inversions of Four Bar Chain

Beam engine (crank and lever mechanism)

Inversions of Four Bar Chain

Crude Oil Lifting Pump (Beam Pump) instaled at Marmul oil field

Inversions of Four Bar Chain• Beam engine (crank and lever mechanism)• Coupling rod of a locomotive (Double crank mechanism)• Watt’s indicator mechanism (Double lever mechanism)

This mechanism is meant for transmitting rotary motion from one wheel to the other wheel

Inversions of Four Bar Chain• Beam engine (crank and lever mechanism)• Coupling rod of a locomotive (Double crank mechanism)• Watt’s indicator mechanism (Double lever mechanism)

Watt's straight line mechanism

• A single slider crank chain is a modification of the basic four barchain. It consist of one sliding pair and three turning pairs.

• It is usually, found in reciprocating steam engine mechanism.• This type of mechanism converts rotary motion into reciprocating

motion and vice versa. As the crank rotates, the cross-headreciprocates in the guides and thus the piston reciprocates in thecylinder.

Single Slider Crank Chain

Pendulum Pump:

In this mechanism, the inversion is obtained by fixing the cylinder orlink 4 (i.e. sliding pair), as shown below. In this case, when the crank(link 2) rotates, the connecting rod (link 3) oscillates about a pinpivoted to the fixed link 4 at A and the piston attached to the pistonrod (link 1) reciprocates.

Inversion of Single Slider Crank Chain

Oscillating Cylinder Engine:The oscillating cylinder engine mechanism, is used to convert thereciprocating motion into rotary motion. In this mechanism, the link3 forming the turning pair is fixed. The link 3 corresponds to theconnecting rod of a reciprocating steam engine mechanism. Whenthe crank (link 2) rotates, the piston attached to piston rod (link 1)reciprocates and the cylinder (link 4) oscillates about a pin pivoted tofixed link at A.

Inversion of Single Slider Crank Chain

Rotary Internal Combustion Engine:It consists of seven cylinders in one plane and all rotates about fixedcentre D, whereas the crank (link 2) is fixed. In this mechanism,when the connecting rod (link 4) rotates, the piston (link 3)reciprocates inside the cylinders forming link 1.

Inversion of Single Slider Crank Chain

Inversion of Single Slider Crank Chain

Inversion of Single Slider Crank Chain

Inversion of Single Slider Crank Chain

Crank and Slotted Quick Return Mechanism:This mechanism is mostly used in shaping machines, slottingmachines. In this mechanism, the link AC (link 3) forming the turningpair is fixed. The link 3 corresponds to connecting rod of areciprocating steam engine.

The crank CB revolves withuniform angular speedabout the fixed centre C. Asliding block is attached tothe crank pin at B slidesalong the slotted bar AP andthus AP to oscillates aboutthe pivoted point A.

Inversion of Single Slider Crank Chain

Crank and Slotted Quick Return Mechanism:Inversion of Single Slider Crank Chain

Next lecture

• Inversions of Single Slider Crank Chain• Crank and Slotted Quick Return Mechanism

(Numerical part)• Inversions of Double Slider Crank Chain• Mechanical Advantages

Commonly Used Lınks and Joınts

Find the number of Degree of Freedom?

Contact details:Rohit Kumar Singla

Email ID: rohit.kumar@thapar.edu