Name : Surendrasing B. Bhil Branch : MechanicalDiv. : MEn. No : 140170119002 Subject : Kinetics of Machines

VishwakarmaGovernmentEngineering College

KINEMATICS

• It is that branch of theory of machine which deals with relative motion between the various parts of machines.

• Kinematics describes the motion of points , bodies without consideration of the causes of motion.

DYNAMICS

• It is that branch of theory of machine which deals with the force and their effects, while acting upon the machine part in motion.

MACHINE

• It is a device which recevies energy in some avilable form and utilizes it to some particular work.

• A machine is a tool containing one or more parts that uses energy to perform an intened Action.

MECHANISM

• It is a device designed to transform input forces and movement into desired set of output forces and movement.

• EXM: 1.Gear and gear trains• 2.Belt and chain drive• 3.Cam and followers• 4.Breaks and clutches

Gear and gear trains

BELT AND CHAIN DRIVE

CAM AND FOLLOWERS

MECHANISM• TYPES• 1.Planar mechanism• 2.Spatial mechanism

• Planar mechanism: it is a mechanism in which all of the relative motion of the rigid bodies are in one plane or in parallel plane.

• It is a mechanical system that is constrained so the trajectories of stomachs in all the bodies of the system lie on aeroplanes parallel to a ground plane.

SPATIAL MECHANISM

• All the relative motion of the rigid bodies are not in a same plane or in different planes.

• It is mechanical system that has at least one body that moves in a way that its point trajectories are general space curves.

Kinematic pair• The two link or element of a machine, when in contact with

each other, are said to form a pair.If relative motion between then is completely or succefully contrained, the pair is knows as kinematic pair.

Classification of kinematic pair

1. sliding pair : when two elements of pair are connected in such a way that one can only slide relative to the other, pair is knows as slidind pair

The type of ralative motion between elements.

2. Turning pair : when the two elements of pair are connect in such a way that one can only turn or revolve ablout a fixed axis of another link,the pair is known as turning pairExample is a shaft with collars in a circular hole.

3. Rolling pair :when the two element of pair are connect in such a way that one rolls over another fixed link, the pair is known as rolling pair

4. Screw pair: when the teo element of pair are connected in such a way that one element turn about the other by screw threads, the pair is known as screw pair

5. Spherical pair: when the two elements of pair are connected in such a way that one element turn or swivels about the other fixed element,the pair formed is called a spherical pair

Contact between the elements• 1. Lower Pair: A kinematic pair is said to be a lower

pair if the links in the pair have surface or area contact between them.2. Higher Pair:A higher

pair is a kinematipair in which the links have point or line contact. Ball bearings, cam and follower are examples of higher pair

The type of closure

• 1. Self Closed Pair: A pair is said to be self closed if the links in the pair have direct mechanical contact, even without the application of external force.

• 2. Force Closed Pair: A kinematic pair is said to be force closed if the links in the pair are kept in contact by the application of external forces. A good example of this type of pair is ball and roller bearings.

Kinetic chain

-> When the kinematic pairs are couple such a way that last link is joined to the first link to transmit definite motion, it is called a kinematic chain Types of joint in chain1. Binary joint2. Ternary joint3. Quaternary joint

Type of kinematic chain(i) Four bar chain or quadric cycle chain: That the

kinematic chain is a combination of four or more kinematic pairs, such that the relative motion between the links or elements is completely constrained.

(ii) Single slider crank chain: A single slider crank chain is a modification of the basic four bar chain. It consist of one sliding pair and three turning pairs. It is,usually, found in reciprocating steam engine mechanism.

(iii) Double slider crank chain: A kinematic chain which consists of two turning pairs and two sliding pair pairs is knows as double slider crank chain

Kinemetic Diagram And

Kinemetic Inversion--

What is Kinemetics ?

• It is that branch of Theory of Machines whichdeals with the relative motion between the various parts of the machines

What is KINEMATICS DIAGRAM

• IT IS GRAPHICAL REPRESENTATION OF DISPLACEMENT,VELOCITY AND ACCELERATION WITH RESPECT TO TIME

GRAPHICAL REPRESENTATION OF DISPLACEMENT W.R.T. TIME

• When the body moves with uniform velocity, EQUAL distance are covered in EQUAL INTERVAL OF TIME.

--• When body moves with variable velocity,Unequal distance are covered in EQUAL interval of TIME

GRAPHICAL REPRESENTATION OF VELOCITY W.R.T. TIME

• When body moves with zero acceleration,then body is said to move with a uniform velocity

--• When the body moves with constant acceleration, the body is said to move with variable velocity

GRAPHICAL REPRESENTATION OF ACCELERATION W.R.T. TIME

• When the body moves with uniform acceleration

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• When the body moves with variable acceleration

Kinematic inversion• Different mechanisms obtained by fixing

different links of a kinematic chain are known as its inversion.

• A slider-crank chain has the following inversion

First inversion

• This inversion is obtained when link 1 is fixed and link2 &4 are made the crank and Slider respectively

Second inversion

• Fixing of link 2 of a slider-crank chain results in the second inversion