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Mechanisms

2011 Project Lead The Way, Inc.Automation and Robotics V!

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What is a "echanism#

A mechanism is the $art o% a machine&hich contains t&o or more $iecesarran'ed so that the motion o% onecom$e(s the motion o% the others.

)enera((y used to* +han'e the direction o% moement

+han'e the ty$e o% moement +han'e the s$eed o% moement +han'e the amount o% tor-ue or %orce

aai(ab(e to do &or

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"echanisms / +han'e irection

"eshed 'ears in a 'ear train

a(&ays turn in o$$osite

directions

The %(o& o% $o&er is reersib(e on(y i% you

can mae the in$ut sha%t turn by turnin'

the out$ut sha%t

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"echanisms / +han'e

"oementRotary

LinearReci$rocatin'

sci((atin'

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"echanisms / +han'e $eed

)ear ratios com$are theout$ut 3or drien 'ear4

to the in$ut3or drie 'ear4

)ear Ratios can be determined usin' number

3n4 o% teeth on the 'ear or diameter 3d4 o% the'ear

5 I% the out$ut 'ear is (ar'er than thein$ut 'ear the s$eed &i(( decrease5 I% the out$ut 'ear is sma((er than the

in$ut 'ear the s$eed &i(( increase.

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im$(e )ear Train

1. In$ut and ut$ut ha%ts$ara((e(

8. A/ $eed is constant

9. : 6 $eed is increased

;. A/ Tor-ue is constant

. : / Ratio

8< teeth*

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Where o @ou 7ind a

im$(e )ear Train#

T&o meshed 'ears

&i(( rotate in

o$$osite directions.

Watch 'ears

11. 7ound in* Watch

e&in' "achine

"otor

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im$(e )ear Train &ith Id(er

1. In$ut and ut$ut ha%ts$ara((e(

8. $eed is constant

9. Tor-ue is constant

;. Ratio 1*1

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Where o @ou 7ind a

im$(e )ear Train &ith Id(er#

T&o meshed 'ears &i(( rotate

in o$$osite directions.

An Idler Gear a((o&s thedrie and drien 'ears to

rotate in the same direction.

>. 7ound in / Pa$er Trans$ort Ro((ers

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:ee( )ear

1. ?0An'(e

2. $eed constant

8. Tor-ue constant

9. In$ut B ut$ut

$eed increases

Tor-ue decreases

;. )ear Ratio 1*1

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Where +an @ou 7ind a

:ee( )ear#

The bee( 'ear is

used to chan'e

rotationa( motion at a

?0 an'(e.

Csin' 'ears &ith

di%%erin' numbers o%

teeth &i(( chan'e thes$eed and tor-ue.

=. 7ound in*

Dand dri((

+ar di%%erentia( ha%t/drien bicyc(e

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i%%erentia( )ear

1. )ears used 6 :ee(

2. AE(es turn 6 ame direction

8. Csed in 6 Vehic(es

9. Pur$ose 6 Whee(s s$in at di%%erent s$eeds

&hen turnin'

Do&stu%%&ors.comFdi%%erentia(

http://var/www/apps/conversion/tmp/scratch_6/at%20http:/auto.howstuffworks.com/differential2.htmhttp://var/www/apps/conversion/tmp/scratch_6/at%20http:/auto.howstuffworks.com/differential2.htm

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Worm and Whee(

1. ?0An'(e

2. $eed is decreased

8. Tor-ue is increased

;. )ear Ratio 29*1

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Where o @ou 7ind a

Worm and Whee(#

A &orm is used toreduce s$eed and

increase tor-ue.

The motion is notreersib(eH a 'ear

cannot drie a &orm.

>. 7ound in*

5 Tunin' mechanism

on strin' instruments5 (ectric motors

5 Winch

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Leadscre&

1. In$ut "oement

rotary2. ut$ut "oement

(inear8. Reo(utions 9.=;

9. 7(o& o% Po&er

Got reersib(e

;. 7orceis increased

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Where o @ou 7ind a

Lead cre

ac Vice

+han'es rotary

moement into (inear

moement

i'ni%icant(y

increases %orce

A $erson can $ut a

(itt(e %orce intoturnin' the hand(e to

moe a heay car.

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Rac and Pinion

1. In$ut "oement

rotary2. ut$ut "oement

(inear9. With a Lar'er Pinion )ear /

the rac &i(( moe a (on'erdistance

;. 7(o& o% Po&er

reersib(e

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Rac

Pinion

Where o @ou 7ind a

Rac and Pinion#

Csed to conert

bet&een rotary

and (inearmotion.

Proides 'ear

reduction tomae it easier to

turn the &hee(s.

=. Csed in steerin' systems

o% cars to conert rotary

motion o% steerin' &hee( tothe side to side motion in

the &hee(s.

Rac and $inion steerin'

http://auto.howstuffworks.com/steering2.htmhttp://auto.howstuffworks.com/steering2.htmhttp://auto.howstuffworks.com/steering2.htmhttp://auto.howstuffworks.com/steering2.htm

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Cniersa( oint

1. An'u(ar Ran'e

B ?0 and J 2=0

2 / 8. $eed and Tor-ue

constant9. Ratio 1*1

;. 7(o& o% Po&er

reersib(e

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Where +an @ou 7ind a

Cniersa( oint#

rie sha%t o%

ehic(es

Po&er tae/o%%

&&&.r-ri(ey.comFima'es$(nF$attersnujoint.j$'

Cniersa( joints areused to transmit rotarymoement at an an'(ethat is not ?0M.

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+hain rie

2. An'(e is $ara((e(

8. $eed is increased

9. Tor-ue is decreased

;. Ratio 1>*80 or 8*;

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Where o @ou 7ind a

+hain and $rocet#

?. Adanta'e o% +hain and

$rocet oer s$ur 'ears*

Trans%er tor-ue and s$eed

oer (on' distances

>. 7ound in*

5 :icyc(e

5 "otorcyc(e

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:e(t rie

2. ha%ts

$ara((e(8. $eed

constant9. Tor-ue

constant

;. Ratio 1*1

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Where o @ou 7ind a

Pu((ey and :e(t#

?. 7ound in*

La&n mo&er

+ar en'ine BELTS

10. :e(ts instead o%

chains*

Nuieter

Less eE$ensie

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+ran and (ider

2. In$ut "oementrotary

8. ut$ut "oementreci$rocatin'

9. (ider "oes2 in. 3or diameter o%

cran4

;. Increased +ran

increased distances(ider moes

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Where o @ou 7ind a

+ran and (ider#

=. 7ound in*

team train

Interna( combustionen'ine

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+am and 7o((o&er

2. In$ut "oement rotary

8. ut$ut "oement

reci$rocatin'

9. 7o((o&er moes u$ anddo&n 1 time %or eery

reo(ution o% the cran

;. 7(o& o% Po&er

not reersib(e

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Where o @ou 7ind a

+am and 7o((o&er#

As a cam rotates, the

%(at %o((o&er is raised

and (o&ered,conertin' rotary

motion to reci$rocatin'

3bac and %orth4

motion.5 The cam $ictured here

&ou(d be reersib(e,

as it is symmetrica(.

=. 7ound in*

+am sha%t

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Ima'e Resources

"icroso%t, Inc. 3200>4. +(i$ Art. Retrieed %rom

htt$*FFo%%ice.microso%t.comFen/usFc(i$artFde%au(t.as$E

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