Ppt on Coupling,Clutches,Brakes

7/21/2019 Ppt on Coupling,Clutches,Brakes

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4/24/15 Subhajyoti Ganguly 1

Presentation on Couplings, Clutches & BrakesBy Subhajyoti Ganguly


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Couplingand Clutchesare power transmission

elements. It is used for transmitting power from

one shaft to the another.

A Brakeis a frictional device whose primary

function is to control the motion of the machine

member.

INTRODUCTION



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Coupling

A coupling is a device used to connect or couple two shafts.Shafts are mostly available up to 7 meters length due to

transport difficulty. To get a greater length , it is necessary to

joint two or more pieces of the shaft using coupling.

Shaft coupling are used in machinery for following purposes:

! To connect shafts of motor and generator which aremanufactured separately and to provide for disconnection

for repairs or alternations.

"! To reduce the transmission of shoc# loads from one shaft

to another.$! To allow misalignment of the shaft or to introduce

mechanical fle%ibility.

&! To introduce protection against overloads.



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Coupling

Rigid

coupling

Sleeve or

muf coupling

Clamp orcomreion

coupling

!lange coupling

"nprotectedtype

#rotected type

!le$ible

coupling

bluhed pintype

%ange coupling

univeral

coupling

&ldham

coupling


Types of couplings


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'It is made from cast iron and very simple to design and manufacture.

'It consists of a hollow cylinder whose inner diameter is the same asdiameter of the shaft.'The hollow cylinder is fitted over the end of the two shafts with the help of

taper sun# #ey.'A #ey and sleeve useful to transmit power from one shaft to the other shaft.'The main disadvantage of this coupling is that it is difficult to assemble

when there is no perfect alignment between shafts.


Sleeve or muff coupling


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' In this coupling , the muff or sleeve is made into two halves parts of cast

iron and they are join together by means of mild steel studs and nuts.

' The advantages of this coupling is that assembling of the coupling is

possible without change the position of shaft.

' This coupling is used for heavy power transmission at moderate speed.

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Clamp or split muff or compression coupling


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' This coupling is having two separate cast iron flanges.

' (ach flange is mounted on the shaft end and #eyed to it.' This coupling prevent catching clothes of wor#man.

' This flange couplings is most accurate and rigid.

' It is used for heavy power transmission at low speed.

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Flange coupling


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' This is modified form of protected type flange coupling.

' This type of coupling has a pins and it wor# as a coupling bolts.' The rubber or leather bushes are used over the pins.

' This coupling is used to connect of shafts which having the small parallel

misalignment, angular misalignment and a%ial displacement.

' This type of coupling is mostly used to couple an electric motor and

machine.

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Bush pin type flange coupling


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' )niversal coupling consists of two similar for#s #eyed on the ends of the two

shafts.

' This coupling is used to connect two shafts whose a%is intersect.

' It also used to connect two shafts, where the angle between two shafts may

be varied when they rotate.

' It is widely used in automobile and machine tools.

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Universal coupling


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' It consist of two flange and a central floating disc.

' This coupling is used in connecting two parallel shafts but not in alignment,and their a%is are at small distance apart.

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Olham!s coupling


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Clutches

*lutch is a one of the form of coupling.*lutches is used to transmit the power from driving shaft

to driven shaft of machine which may be re+uired to start or

stop fre+uently.

It is so designed that the two members may be engagedor disengaged whenever re+uired either by a hand operated

device or automatically by the action of some power driven

devices.



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Types of clutches

clutche

mechanical

poitivecontact

clutche

ja, clutch

toothed clutch

-riction

clutche

dic clutch

cone clutch

centri-ugal clutch

pneumatic

hydraulic

electromagnetic



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' This type of clutch consists of two flanges, one flange is rigidly to the driving

shaft and other flange fitted to the driven shaft.

' Single disc clutches are used in automobiles.' hen large tor+ue transmission is re+uired the multi disc clutch are used.

' -ulti disc clutch has more number of contact surfaces discs on driving and

driven shaft.


Disc clutches


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' The cone clutch consists two cones , one internal cone fi%ed to the driven

shaft and another cone fitted on the driven shaft.

' The operating lever used only for disengagement of the clutch.' The main advantage of cone clutch over the disc clutch is very simple and

re+uired less a%ial pressure to disengaged the clutch.


Cone clutch


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' It consists of a number of shoes on the inside of a drum or rim of the pulley.

'The upper surface of the shoes are covered with a friction material.' The spider is fitted on the driving shaft.

' hen centrifugal force is e+ual to spring force, the shoe is just floating.

' ut, when centrifugal force higher than the spring force, the shoes moves

outward and comes into contact with the driven member and pressure

against it.

' The increase of speed causes the shoes to press harder and clutch transmit

more power.


Centrifugal clutch


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' It is consists of segmental projections on one of the flange and

corresponding recesses on other flange on the driven shaft.

' /riving flange rigidly #eyed to the driving shaft while the other flange is#eyed to driven shaft by splines so that it can slide on that shaft.

' The sliding flange engage with the fi%ed flange to transmit the motion and

power from driving shaft.

' This clutch is used for the transmission of power in agricultural e+uipment

li#e tractor, thresher, etc.

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"a# clutch


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Brakes

A bra#e is a mechanical device which producesfrictional resistance against moving machine

member, in order to slow down the motion of

machine.In the process of performing this function, the

bra#e absorbs #inetic energy of moving member

and the bra#e absorbs potential energy of

lowering member.The energy absorbed by bra#es is released to

surrounding in form of heat.

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Types of $rakes


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Single bloc# or shoe bra#e:

' A single bloc# is consists of a bloc# which is pressed against the rim of

revolving bra#e wheel drum.

' This bra#e is used in railway trains and tram cars.

' The prony bra#e is e%ample of bloc# bra#e.

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Block $rake


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Dou$le $lock or shoe $rake%

'It consists of two bra#e bloc#s at the opposite ends of the wheel.

'These shoes apply force to both sides of wheel and reduces the

unbalanced force on the shaft.'The spring pulls the upper end of bra#e arms together and bra#e is

applied.'hen a force is applied to the bell cran# lever, the spring is compressed

and the bra#e is released.'This bra#e is used on electric cranes.'The bicycle bra#e is e%ample of double bloc# bra#e.

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' A band bra#e consists of a fle%ible steel band lined with friction material,

which wrap to the bra#e drum.

' hen an upward force is applied to the lever end, the lever turns about the

fulcrum pin and tightens the band on the drum and hence the bra#es are

applied.

' The friction between the band and the drum provides the bra#ing force.

' This type of bra#e is used in civil construction e+uipment and also in

automobiles as hand bra#e.' The rope bra#e is e%ample of band bra#e.


Ban $rake


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' An internal e%panding shoe bra#e consists of two shoes.

' The outer surface of the shoes are covered with friction material.

' (ach shoe is pivoted at one end about a fi%ed fulcrum and other end restsagainst cam.

' hen the cam is operated, the shoe are pushed outwards against bra#e

drum.

' The friction between the shoes and the drum produces the bra#ing tor+ue.

' This type of bra#e is commonly used in motor cars and light truc#s.


Internal e&paning shoe $rake


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Thankyou


Ppt on Coupling,Clutches,Brakes

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