Inversion
of Mechanism
1) If one link of a
kinematic chain is fixed then, it is called a “Mechanism’.
2) The process of fixing different links one at a time to get different mechanisms is called ‘Inversion of mechanism’
Types of Inversion:
i) Four bar chain.
ii) Single slider crank-chain.
iii) Double slider crank-chain
i) Inversion of Four bar chain
One of the most useful and most common mechanisms is the four-bar linkage. In this mechanism, the link which can make complete rotation is known as crank (link 2). The link which oscillates is known as rocker or lever (link 4). And the link connecting these two is known as coupler (link 3). Link 1 is the frame.
A beam engine is a type of steam engine where a pivoted overhead beam is used to apply the force from a vertical piston to a vertical connecting rod.
ii) Inversion of Single slider crank-chain
The function of the reciprocating engine is to convert the reciprocating motion into rotary motion. It is a simplest from of single slider crank chain mechanism. In reciprocating engine there is one sliding pair and three turning pairs. In figure there are three turning pairs and the sliding pair is formed between the cross head and the guides. Link 1 is fixed (frame). Link 2 will act as a crank, which rotates. Link 3 is a connecting rod and link 4 is a cross head.
iii)Inversions of Double slider Crank chain:
It consists of two sliding pairs and two turning pairs. They are three important inversions of double slider crank chain. 1) Elliptical trammel. 2) Scotch yoke mechanism. 3) Oldham‘s Coupling.
=> i). Elliptical Trammel:
This is an instrument for drawing ellipses. Here the slotted link is fixed. The sliding block P and Q in vertical and horizontal slots respectively. The end R generates an
ellipse with the displacement of sliders P and Q.
=> ii). Scotch yoke mechanism: This mechanism, the slider P is fixed. When PQ rotates above P, the slider Q reciprocates in the vertical slot. The mechanism is used to convert rotary to reciprocating mechanism.
=> iii) Oldham’s coupling: The third inversion of obtained by fixing the link connecting the 2 blocks P & Q. If one block is turning through an angle, the frame and the other block will also turn through the same angle.
2) The process of fixing different links one at a time to get different mechanisms is called ‘Inversion of mechanism’
Types of Inversion:
i) Four bar chain.
ii) Single slider crank-chain.
iii) Double slider crank-chain
i) Inversion of Four bar chain
One of the most useful and most common mechanisms is the four-bar linkage. In this mechanism, the link which can make complete rotation is known as crank (link 2). The link which oscillates is known as rocker or lever (link 4). And the link connecting these two is known as coupler (link 3). Link 1 is the frame.
A beam engine is a type of steam engine where a pivoted overhead beam is used to apply the force from a vertical piston to a vertical connecting rod.
ii) Inversion of Single slider crank-chain
The function of the reciprocating engine is to convert the reciprocating motion into rotary motion. It is a simplest from of single slider crank chain mechanism. In reciprocating engine there is one sliding pair and three turning pairs. In figure there are three turning pairs and the sliding pair is formed between the cross head and the guides. Link 1 is fixed (frame). Link 2 will act as a crank, which rotates. Link 3 is a connecting rod and link 4 is a cross head.
iii)Inversions of Double slider Crank chain:
It consists of two sliding pairs and two turning pairs. They are three important inversions of double slider crank chain. 1) Elliptical trammel. 2) Scotch yoke mechanism. 3) Oldham‘s Coupling.
=> i). Elliptical Trammel:
This is an instrument for drawing ellipses. Here the slotted link is fixed. The sliding block P and Q in vertical and horizontal slots respectively. The end R generates an
ellipse with the displacement of sliders P and Q.
=> ii). Scotch yoke mechanism: This mechanism, the slider P is fixed. When PQ rotates above P, the slider Q reciprocates in the vertical slot. The mechanism is used to convert rotary to reciprocating mechanism.
=> iii) Oldham’s coupling: The third inversion of obtained by fixing the link connecting the 2 blocks P & Q. If one block is turning through an angle, the frame and the other block will also turn through the same angle.