MECHANISMS Prof. kiran gore

How Mechanisms are made? Mechanism consist of following element Mechanisms are used to obtain required motion in machines. It is capable of transforming one type of input motion in to another. How Mechanisms are made? Mechanism consist of following element Link or Element Kinematic Pair Kinematic Chain

What is a Link or Element? A resistant body, which is a part of machine and has a motion relative to other connected part is known as an Element or Link. Cylinder Piston Crank Connecting Rod

What is resistant body ? The body, which is capable of transmitting the forces with negligible deformation is called as resistant body.

Examples of Link or Element: Link1- Piston LInk2- Cylinder Link 3- Crank Link 4 Connecting Rod Cylinder Piston Crank Connecting Rod

What is a kinematics Pair? When two element or link which are connected together in such way that the motion between them is constrained (in a definite direction) is known as kinematic Pair. Kinematic Pair 2 1.Kinematic Pair –I Crank & Frame 2.Kinematic Pair –II Crank & Connecting Rod 3.Kinematic Pair- III Connecting Rod & Piston 4.Kinematic Pair – IV Piston & Cylinder 4 2 3 1

Kinematic chain when the kinematic pair are connected in such manner that the last link is joined to the first link to transmit completely or successfully constrained motion, then it is called as kinematic chain

Ex. Kinematic chain

Mechanisms Example for Mechanism If one of the links or element of a kinematic chain is fixed, the arrangement can be used for transmitting or transforming the motion, and it is called as Mechanism. In short Mechanism is a kinematic chain with one link fixed. Example for Mechanism

Types of kinematic chain or Mechanism Four bar chain or quadric cycle chain. Single slider crank chain Double slider crank chain

Four Bar Chain

Four Bar Chain Mechanism It is simplest kinematics chain, consists of 4 links & forming 4 turning pair; A0, A, B, B0. Each link have different length. If 1 link in 4 bar chain is fixed, then it is called as bar chain Mechanism & other 3 links moves relative to each other.

Four Bar Chain Mechanism It is simplest kinematics chain, consists of 4 links & forming 4 turning pair; A0, A, B, B0. Each link have different length. If 1st link in 4 bar chain is fixed, then it is called as 4 bar chain Mechanism & other 3 links moves relative to each other.

Slider Crank Chain A single crank chain is a modification of the basic four-bar chain. It consists of one sliding pair and three turning pairs. It is found in reciprocating steam engine mechanism. This type of mechanism converts rotary motion into reciprocating motion and vice versa. Links: Frame and cylinder, crank, connecting rod, crosshead or piston.

First Inversion of a single slider crank chain Reciprocating engine and Air compressor Links – 1- fixed 2- crank 3- connecting rod 4- slider

Slider Crank mechanism

Comparison between Mechanism & Machine

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