DESIGN AND FABRICATION OF RESISTIVE EXERCISE DEVICE A PROJECT REPORT
Submitted by
N.UDAYASAI
1021220101
K.PRASANTH NAG
1021220109
S.ANJI REDDY
1021220114
N.JASHWANTH KUMAR
1021220149
in partial fulfillment for the award of the degree of BACHELOR OF TECHNOLOGY
in MECHANICAL ENGINEERING
SRM UNIVERSITY RAMAPURAM MAY 201
SRM UNIVERSITY RAMAPURAM
BONAFIDE CERTIFICATE Certified
that
this
project
report
!D ES IG N
FABRICATION OF RESISTIVE EXERCISE DEVICE"
bonafi de
work
of
A ND
is the
“NAGUBANDI UDAYASAI #1021220101
%$KAMMA PRASANTH NAG #1021220109$% SAMALA ANJI REDDY #1021220114$% NARE JASWANTH REDDY #1021220149$"
wh o
carried out the project work under my supervision.
SIGNATURE
SIGNATURE
GUIDE M&.M.SOUNDAR% M.E
HEADOFTHEDEPARTMENT M&.K.C.UDAIYAKUMAR% M.T'().#P).D.$
Assistant Professor (.!" Assistant Professor (#.!" $epartment of Mechanica% &n'ineerin' $epartment of Mechanica% &n'ineerin'
INTERNALEXAMINER
EXTERNALEXAMINER
ACKNOWLEDGEMENT
e p%ace on re'ard our deep sense of 'ratitude to our be%oved Chance%%or D&.T.R.PACHAMUTHU for providin' us with the re)uisite infrastructure
throu'hout the course.
e take the opportunity to e*tend our hearty thanks to our Chairman+ #RM University
Ramapuram
Campus+
D&.R.SHIVAKUMAR for
his
constant
encoura'ement.
e take the opportunity to e*tend our hearty thanks to our $ean+ D&.V.SUBBIAH BHARATHIfor his constant encoura'ement.
e convey our sincere thanks to our ,ice Principa% (Academic" D&.L.ANTONY MICHAEL RAJ for his interest and support throu'hout this project.
e take the privi%e'e to e*tend our hearty thanks to the -ead of the $epartment+ M&.K.C.UDAIYAKUMAR% M.T'().% #P).D.$%Asst. Professor(#.!" for his su''estions+ support and encoura'ement towards the comp%etion of the project with perfection. e take the privi%e'e to e*tend our hearty thanks to the Project coordinator+ M&.D.K.MOHAN KUMAR% M.E.% M.B.A.% #P).D.$% Asst.Professor (#r.!"+
Mechanica% &n'ineerin' $epartment for his su''estions+ support and encoura'ement towards the comp%etion of the project with perfection.
e
e*press
'ratitude
to
our
'uide
M&.M.SOUNDAR%
M.E.%
Asst.Professor (.!"+ Mechanica% &n'ineerin' $epartment for his sustained encoura'ement+ consecutive criticisms and constant 'uidance throu'hout this project work.
TABLE OF CONTENTS CHAPTER NO.
LISTOFCONTENTS
PAGE NO.
LISO TT FABLE
***
LIST OF IGURES
*+
A/#0RAC0
1.
INTRODUCTION
1
1.1/riefoverview
1
1.2 e%din'
2
1.2.1Arcwe%din'
3
1.2.2 Power supp%ies
3
1.2.3Processes
4
1.2.4 #hie%d meta% arc we%din'
4
1.2.5e%din'joint
6
!ears 1.3
7
1.3.10ypesof'ears
8
1.3.2 9omenc%ature of 'ears 1.4
/e%t and pu%%ey system 2. ,. 4.
1: 18
LITERATURE REVIEW
20
STATEMENTOFPROBLEM
22
METHODOLOGY
2,
4.1#e)uenceofdesi'n
23
4.1.1,acuumcy%inders
24
4.1.2 Rack and pinion mechanism
24
4.1.3 screw rod and pu%%ey mechanism -.
25
EXPERIMENTALWORK
2
5.1 ;ntroduction 5.2 #e%ection of materia% 5.2.1 Properties
26 26 26
5.2.2 Manufacturin' cost 5.2.3
27 27
1
5.2.4 Avai%abi%ity of materia%
27
5.2.5#paceconsideration
27
TABLE OF CONTENTS CHAPTER NO.
LISTOFCONTENTS
PAGE NO.
5.2.6 Cost
27
5.3 ei'ht ca%cu%ation 5.4 $esi'n
28 3:
5.5Components
33
5.6#pecifications
34
5.6.1 ,acuum cy%inder specifications
35
5.7 =abrication
36
5.8Construction
4:
5.> orkin'
4:
5.1: Cost estimation .
RESULTSANDDISCUSSION
.
ADVANTAGESANDLIMITATIONS
/.
CONCLUSION
9.
41 4, 44 4-
FUTURSECOPE
4
REFERENCE
2
LIST OF TABLES TABLENO. 5.1 5.2 5.3 5.4
DESCRIPTION
PAGENO.
ComponentsofResistivee*ercisedevice
33
#pecifications
34
,acuumcy%inderspecifications Cost estimation
3
32 38
LIST OF FIGURES FIGURENO.
DESCRIPTION
1.1 1.2 1.3 1.4
e%din'types 7
!ears
7
arm 'ear
>
Rack and Pinion 'earin'
1.6
!ear nomenc%ature
1.7
=%at be%t on be%t pu%%ey
1.8
/e%tandPu%%eysystem
1.>
Cone pu%%ey
5.1
/asic desi'n
5.2
=ront view
5.3
view #ide
5.6
?iftin' rod
5.> 5.1: 5.11 5.12
1: 18 18
3: 31 31 32
Main frame
5.8
1:
18
view 0op
5.5
5.7
6
e%ded butt joint
1.5
5.4
PAGENO.
36 36
,acuum cy%inders
36
Cy%inderpistonwithrack
37
=%ywhee%setupandmainarm
37
C%amp adjustment Pu%%ey setup
38 38
=ina% assemb%ed and finished product
4
3>
ABSTRACT =itness bein' the main concerned prob%em of the present 'eneration. 0here is an immediate necessity for economica% and %on' %astin' fitness machinery. -u'e wei'hts+ used as force providers today are not on%y increasin' the cost of the e)uipment but a%so increasin' the wear and tear. #o+ usin' a%ternative methods to create the force instead of wei'hts wou%d drastica%%y decrease the cost of the e)uipment. 0he idea of the project is to rep%ace the traditiona% wei'hts with a vacuum or air pressured e)uipment (e*@ cy%inders" and a%so to provide a mechanism to adjust the force re)uired ( this wi%% e%iminate the prob%em of chan'in' the wei'hts". 0he mechanism wou%d inherit the idea of f%ywhee% and arm mechanism to a%ter the tor)ue re%ative to the arm position. Coup%in' various e*ercises with the mechanism wou%d be another task to be accomp%ished in order to provide economic and robust mode%.
CHAPTER 1 INTRODUCTION 1.1B&*' +'&+*' =itness bein' the main concerned prob%em of the present 'eneration. 0here is an immediate necessity for economica% and %on' %astin' fitness machinery. -u'e wei'hts+ used as force providers today are not on%y increasin' the cost of the e)uipment but a%so increasin' the wear and tear. #o+ usin' a%ternative methods to create the force instead of wei'hts wou%d drastica%%y decrease the cost of the e)uipment. 9umerous e*ercise devices have been desi'ned and are on the market 0he vast majority of these devices are desi'ned for norma% 'ravity conditions. =or e*amp%e+ many devices have been deve%oped of the “wei'ht type wherein ei'hts are emp%oyed in the resistance to the e*ertion of muscu%ar force. Perhaps the simp%est of these are barbe%%s+ but a host of machines of this type have been deve%oped which emp%oy. ei'ht stacks of a variety of types a'ainst which muscu%ar force is e*erted in e*ercisin' to achieve or maintain muscu%ar deve%opment. Machines of the “wei'ht type suffer from severa% common deficiencies+ which detract from their desire abi%ity. #uch machines are norma%%y rather cumbersome and e*pensive. 0hey do not possess the deity of adjustabi%ity (i.e.+ they are %imited to the ei'ht stack increments". Perhaps the most obvious aspect of these types of devices is that they are very heavy due to the inherent nature of the use of ei'ht stacks. Accordin'%y+ a need has arisen for an e*ercise device for Bero or micro 'ravity conditions hich+ for e*amp%e+ simu%ates the %iftin' of free ei'hts in a 1' environment and hich is compact ith re%ative%y %ow mass+ provides for numerous different e*ercises+ is adjustab%e for different %oads+ is adjustab%e for different siBed individua%s and i%% operate for %on' periods ith minima% maintenance. ;n accordance with the present invention+ an e*ercise device is provided which has %oads app%ied by both a vacuum cy%inder and f%y hee%. hen used in a space app%ication+ this device simu%ates the %iftin' of free ei'hts in a 1' environment. A%so in accordance ith the present invention+ an e*ercise device is provided which comprises a vacuum cy%inder and a %oad adjustin' arm base assemb%y. 1
Accordin'%y+ an object of the present invention is to provide an e*ercise device for space app%ication+ which simu%ates the %iftin' of free ei'hts in a 1' environment. Accordin'%y+ a second object of the present inven tion is to provide an e*ercise device havin' a vacuum cy%inder and a uni)ue %oadadjustin' feature+ which varies the otherwise constant %oad provided by a vacuum cy%inder. A third object of the present invention is to provide an improved e*ercisin' apparatus for terrestria% app%ications such as+ for e*amp%es@ a home 'ym for persona% use rehabi%itation and physica% therapy purposes and an e*ercise device for a hea%th c%ub+ hote%+ or cruise ship. =urther objects and advanta'es are to provide improved e%ements and arran'ements thereof in an e*ercise apparatus. =or the purpose described which is dependab%e+ economica%+ durab%e+ and fu%%y effective in accomp%ishin' the intended purpose.
1.2 W'3*56 e%din' is a fabrication or scu%ptura% process that joins materia%s+ usua%%y meta%s or thermop%astics+ by causin' fusion+ which is distinct from %ower temperature meta%joinin' techni)ues such as braBin' and so%derin'+ which do not me%t the base meta%. ;n addition to me%tin' the base meta%+ a fi%%er materia% is often added to the joint to form a poo% of mo%ten materia% (the we%d poo%" that coo%s to form a joint that can be as stron'+ or even stron'er+ than the base materia%.
Pressure may a%so be used in
conjunction with heat+ or by itse%f+ to produce a we%d. A%thou'h %ess common+ there are a%so so%id state we%din' processes such as friction we%din' or shie%ded active 'as we%din' in which meta% does not me%t. #hie%ded meta% arc we%din' (#MA" a%so known as Dstick we%din' or e%ectric we%din'D+ uses an e%ectrode that has f%u* around it to protect the we%d pudd%e. 0he e%ectrode ho%der ho%ds the e%ectrode as it s%ow%y me%ts away.
#%a' protects the we%d
pudd%e from atmospheric contamination. •
!as tun'sten arc we%din' (!0A" a%so known as 0;! (tun'sten+ inert 'as"+ uses a nonconsumab%e tun'sten e%ectrode to produce the we%d. 0he we%d area is protected from atmospheric contamination by an inert shie%din' 'as such as ar'on or he%ium.
2
•
!as meta% arc we%din' (!MA" common%y termed M;! (meta%+ inert 'as"+ uses a wire feedin' 'un that feeds wire at an adjustab%e speed and f%ows an ar'on based shie%din' 'as or a mi* of ar'on and carbon dio*ide (C2" over the we%d pudd%e to protect it from atmospheric contamination.
•
=%u*cored arc we%din' (=CA" a%most identica% to M;! we%din' e*cept it uses a specia% tubu%ar wire fi%%ed with f%u* it can be used with or without shie%din' 'as+ dependin' on the fi%%er.
•
#ubmer'ed arc we%din' (#A" uses an automatica%%y fed consumab%e e%ectrode and a b%anket of 'ranu%ar fusib%e f%u*. 0he mo%ten we%d and the arc Bone are protected from atmospheric contamination by bein' Dsubmer'edD under the f%u* b%anket.
•
&%ectro s%a' we%din' (&#" a hi'h%y productive+ sin'%e pass we%din' process for thicker materia%s between 1 inch (25 mm" and 12 inches (3:: mm" in a vertica% or c%ose to vertica% position. Many different ener'y sources can be used for we%din'+ inc%udin' a 'as f%ame+
an e%ectric arc+ a %aser+ an e%ectron beam+ friction+ and u%trasound. hi%e often an industria% process+ we%din' may be performed in many different environments+ inc%udin' in open air+ under water + and in outer space. e%din' is a haBardous undertakin' and precautions are re)uired to avoid burns+ e%ectric shock + vision dama'e+ inha%ation of poisonous 'ases and fumes+ and e*posure to intense u%travio%et radiation.
1.2.1 A&( '3*56 0hese processes use a
we%din' power supp%y to create and maintain an e%ectric
arc between an e%ectrode and the base materia% to me%t meta%s at the we%din' point. 0hey can use either direct ($C" or a%ternatin' (AC" current+ and consumab%e or non consumab%e e%ectrodes. 0he we%din' re'ion is sometimes protected by some type of inert or semiinert 'as+ known as a shie%din' 'as+ and fi%%er materia% is sometimes used as we%%. 0o supp%y the e%ectrica% power necessary for arc we%din' processes+ a variety of different power supp%ies can be used. 0he most common we%din' power supp%ies
3
are constant current power supp%ies and constant vo%ta'e power supp%ies. ;n arc we%din'+ the %en'th of the arc is direct%y re%ated to the vo%ta'e+ and the amount of heat input is re%ated to the current. Constant current power supp%ies are most often used for manua% we%din' processes such as 'as tun'sten arc we%din' and shie%ded meta% arc we%din'+ because they maintain a re%ative%y constant current even as the vo%ta'e varies. 0his is important because in manua% we%din'+ it can be difficu%t to ho%d the e%ectrode perfect%y steady+ and as a resu%t+ the arc %en'th and thus vo%ta'e tend to f%uctuate. Constant vo%ta'e power supp%ies ho%d the vo%ta'e constant and vary the current+ and as a resu%t+ are most often used for automated we%din' processes such as 'as meta% arc we%din'+ f%u* cored arc we%din'+ and submer'ed arc we%din'. ;n these processes+ arc %en'th is kept constant+ since any f%uctuation in the distance between the wire and the base materia% is )uick%y rectified by a %ar'e chan'e in current. =or e*amp%e+ if the wire and the base materia% 'et too c%ose+ the current wi%% rapid%y increase+ which in turn causes the heat to increase and the tip of the wire to me%t+ returnin' it to its ori'ina% separation distance. 0he type of current used p%ays an important ro%e in arc we%din'. Consu mab%e e%ectrode processes such as shie%ded meta% arc we%din' and 'as meta% arc we%din' 'enera%%y use direct current+ but the e%ectrode can be char'ed either positive%y or ne'ative%y. ;n we%din'+ the positive%y char'ed anode wi%% have a 'reater heat concentration+ and as a resu%t+ chan'in' the po%arity of the e%ectrode has an impact on we%d properties. ;f the e%ectrode is positive%y char'ed+ the base meta% wi%% be hotter+ increasin' we%d penetration and we%din' speed. A%ternative%y+ a ne'ative%y char'ed e%ectrode resu%ts in more sha%%ow we%ds. 9on consumab%e e%ectrode processes+ such as 'as tun'sten arc we%din'+ can use either type of direct current+ as we%% as a%ternatin' current. -owever+ with direct current+ because the e%ectrode on%y creates the arc and does not provide fi%%er materia%+ a positive%y char'ed e%ectrode causes sha%%ow we%ds+ whi%e a ne'ative%y char'ed e%ectrode makes deeper we%ds. A%ternatin' current rapid%y moves between these two+ resu%tin' in mediumpenetration we%ds. ne disadvanta'e of AC+ the fact that the arc must be rei'nited after every Bero crossin'+ has been addressed with the invention of specia% power units that produce a s)uare wave pattern instead of the norma% sine wave + makin' rapid Bero crossin's possib%e and minimiBin' the effects of the prob%em.
4
ne of the most common types of arc we%din' is shie%ded meta% arc we%din' (#MA" it is a%so known as manua% meta% arc we%din' (MMA" or stick we%din'. &%ectric current is used to strike an arc between the base materia% and consumab%e e%ectrode rod+ which is made of fi%%er materia% (typica%%y stee%" and is covered with a f%u* that protects the we%d area from o*idation and contamination by producin' carbon dio*ide (C2" 'as durin' the we%din' process. 0he e%ectrode core itse%f acts as fi%%er materia%+ makin' a separate fi%%er unnecessary.
1.2.2 S)*'3 7'83 &( '3*56 0he process is versati%e and can be performed with re%ative%y ine*pensive e)uipment+ makin' it we%% suited to shop jobs and fie%d work. An operator can become reasonab%y proficient with a modest amount of trainin' and can achieve mastery with e*perience. e%d times are rather s%ow+ since the consumab%e e%ectrodes must be fre)uent%y rep%aced and because s%a'+ the residue from the f%u*+ must be chipped away after we%din'. =urthermore+ the process is 'enera%%y %imited to we%din' ferrous materia%s+ thou'h specia% e%ectrodes have made possib%e the we%din' of cast iron+ nicke%+ a%uminum+ copper+ and other meta%s. A re%ated process+ f%u* cored arc we%din' (=CA"+ uses simi%ar e)uipment but uses wire consistin' of a stee% e%ectrode surroundin' a powder fi%% materia%. 0his cored wire is more e*pensive than the standard so%id wire and can 'enerate fumes andEor s%a'+ but it permits even hi'her we%din' speed and 'reater meta% penetration. !as tun'sten arc we%din' (!0A"+ or tun'sten inert 'as (0;!" we%din'+ is a manua% we%din' process that uses a nonconsumab%e tun'sten e%ectrode+ an inert or semiinert 'as mi*ture+ and a separate fi%%er materia%. &specia%%y usefu% for we%din' thin materia%s+ this method is characteriBed by a stab%e arc and hi'h )ua%ity we%ds+ but it re)uires si'nificant operator ski%% and can on%y be accomp%ished at re%ative%y %ow speeds. !0A can be used on near%y a%% we%dab%e meta%s+ thou'h it is most often app%ied to stain%ess stee% and %i'ht meta%s. ;t is often used when )ua%ity we%ds are e*treme%y important+ such as in bicyc%e+ aircraft and nava% app%ications. A re%ated process+ p%asma arc we%din'+ a%so uses a tun'sten e%ectrode but uses p%asma 'as to make the arc. 0he arc is more concentrated than the !0A arc+ makin' transverse contro% more critica% and thus 'enera%%y restrictin' the techni)ue to a mechaniBed 5
process. /ecause of its stab%e current+ the method can be used on a wider ran'e of materia% thicknesses than can the !0A process and it is much faster. ;t can be app%ied to a%% of the same materia%s as !0A e*cept ma'nesium+ and automated we%din' of stain%ess stee% is one important app%ication of the process. A variation of the process is p%asma cuttin'+ an efficient stee% cuttin' process. #ubmer'ed arc we%din' (#A" is a hi'hproductivity we%din' method in which the arc is struck beneath a coverin' %ayer of f%u*. 0his increases arc )ua%ity+ since contaminants in the atmosphere are b%ocked by the f%u*. 0he s%a' that forms on the we%d 'enera%%y comes off by itse%f+ and combined with the use of a continuous wire feed+ the we%d deposition rate is hi'h. orkin' conditions are much improved over other arc we%din' processes+ since the f%u* hides the arc and a%most no smoke is produced. 0he process is common%y used in industry+ especia%%y for %ar'e products and in the manufacture of we%ded pressure vesse%s. ther arc we%din' processes inc%ude atomic hydro'en we%din'+ e%ectro s%a' we%din'+ e%ectro 'as we%din'+ and stud arc we%din'.
1.2., W'3*56 :*58
F*6 1.1 '3*56 8;<'=
e%ds can be 'eometrica%%y prepared in many different ways. 0he five basic types of we%d joints are the butt joint+ %ap joint+ corner joint+ ed'e joint+ and 0joint (a variant of this %ast is the cruciform joint". ther variations e*ist as we%%Ffor e*amp%e+ doub%e, preparation joints are characteriBed by the two pieces of materia% each taperin' to a sin'%e center point at oneha%f their hei'ht. #in'%eU and doub%eU preparation joints are a%so fair%y commonFinstead of havin' strai'ht ed'es %ike the 6
sin'%e, and doub%e, preparation joints+ they are curved+ formin' the shape of a U. ?ap joints are a%so common%y more than two pieces thickFdependin' on the process used and the thickness of the materia%+ many pieces can be we%ded to'ether in a %ap joint 'eometry. Many we%d in' proce sses re)ui re the use of a particu%ar joint desi'n for e*amp%e+ resistance spot we%din'+ %aser beam we%din'+ and e%ectron beam we%din' are most fre)uent%y performed on %ap joints. ther we%din' methods+ %ike shie%ded meta% arc we%din'+ are e*treme%y versati%e and can we%d virtua%%y any type of joint. #ome processes can a%so be used to make mu%tipass we%ds+ in which one we%d is a%%owed to coo%+ and then another we%d is performed on top of it. 0his a%%ows for the we%din' of thick sections arran'ed in a sin'%e, preparation joint+ for e*amp%e.
F*6 1.2 W'3 >?88 :*58
0he cross section of a we%d butt joint+ with the darkest 'ray representin' the we%d or fusion Bone+ the medium 'ray the heataffected Bone+ and the %i'htest 'ray base materia%. After we%din'+ a number of distinct re'ions can be identified in the we%d area. 0he we%d itse%f is ca%%ed the fusion BoneFmore specifica%%y+ it is where the fi%%er meta% was %aid durin' the we%din' process. 0he properties of the fusion Bone depend primari%y on the fi%%er meta% used+ and its compatibi%ity with the base materia%s. ;t is surrounded by the heataffected Bone+ the area that had its microstructure and properties a%tered by the we%d. 0hese properties depend on the base materia%Gs behavior when subjected to heat. 0he meta% in this area is often weaker than both the base materia% and the fusion Bone+ and is a%so where residua% stresses are found.
1., G'&=
7
F*6 1., G'&=
0wo meshin' 'ears transmittin' rotationa% motion. 9ote that the sma%%er 'ear is rotatin' faster. A%thou'h the %ar'er 'ear is rotatin' %ess )uick%y+ its tor)ue is proportiona%%y 'reater. ne subt%ety of this particu%ar arran'ement is that the %inear speed at the pitch diameter is the same on both 'ears A 'ear or co'whee% is a rotatin' machine part havin' cut teeth+ or co's+ which mesh with another toothed part to transmit tor)ue. !eared devices can chan'e the speed+ tor)ue+ and direction of a power source. !ears a%most a%ways produce a chan'e in tor)ue+ creatin' a mechanica% advanta'e+ throu'h their 'ear ratio + and thus may be considered a simp%e machine. 0he teeth on the two meshin' 'ears a%% have the same shape. 0wo or more meshin' 'ears+ workin' in a se)uence+ are ca%%ed a
'ear train or
a transmission. A 'ear can mesh with a %inear toothed part+ ca%%ed a rack+ thereby producin' trans%ation instead of rotation. 0he 'ears in a transmission are ana%o'ous to the whee%s in a crossed be%t pu%%ey system. An advanta'e of 'ears is that the teeth of a 'ear prevent s%ippa'e. hen two 'ears mesh+ if one 'ear is bi''er than the other+ a mechanica% advanta'e is produced+ with the rotationa% speeds+ and the tor)ues+ of the two 'ears differin' in proportion to their diameters. ;n transmissions with mu%tip%e 'ear ratiosFsuch as bicyc%es+ motorcyc%es+ and carsthe term D'earD as in Dfirst 'earD refers to a 'ear ratio rather than an actua% physica% 'ear. 0he term describes simi%ar devices+ even when the 'ear ratio is continuous rather than discrete+ or when the device does not actua%%y contain 'ears+ as in a continuous%y variab%e transmission. An e*terna% 'ear is one with the teeth formed on the outer surface of a cy%inder or cone. Converse%y+ an interna% 'ear is one with the teeth formed on the inner surface of a cy%inder or cone. =or beve% 'ears+ an interna% 'ear is one with the
pitch an'%e
e*ceedin' >: de'rees. ;nterna% 'ears do not cause output shaft direction reversa%.
1.4 T;<'= 6'&= 1.4.1 S
(but usua%%y of specia% form to achieve a constant drive ratio+ main%y invo%ute but %ess common%y cyc%oida%"+ the ed'e of each tooth is strai'ht and a%i'ned para%%e% to the a*is of rotation. 0hese 'ears mesh to'ether correct%y on%y if fitted to para%%e% shafts.
1.4.2 W&7
F*6 1.4 W&7 6'&
orm 'ear resemb%es screws. A worm is meshed with a worm whee%+ which %ooks simi%ar to a spur 'ear. ormand'ear sets are a simp%e and compact way to achieve a hi'h tor)ue+ %ow speed 'ear ratio. =or e*amp%e+ he%ica% 'ears are norma%%y %imited to 'ear ratios of %ess than 1:@1 whi%e wormand'ear sets vary from 1:@1 to 5::@1. A disadvanta'e is the potentia% for considerab%e s%idin' action + %eadin' to %ow efficiency. A worm 'ear is a species of he%ica% 'ear+ but its he%i* an'%e is usua%%y somewhat %ar'e (c%ose to >: de'rees" and its body is usua%%y fair%y %on' in the a*ia% direction. 0hese attributes 'ive it screw %ike )ua%ities. 0he distinction between a worm and a he%ica% 'ear is that at %east one tooth persists for a fu%% rotation around the he%i*. ;f this occurs+ it is a GwormG if not+ it is a Ghe%ica% 'ear. A worm may have as few as one tooth. ;f that tooth persists for severa% turns around the he%i*+ the worm appears+ superficia%%y+ to have more than one tooth+ but what one in fact sees is the same tooth reappearin' at interva%s a%on' the %en'th of the worm. 0he usua% screw nomenc%ature 9
app%ies@ a onetoothed worm is ca%%ed sin'%e thread or sin'%e start a worm with more than one tooth is ca%%ed mu%tip%e thread or mu%tip%e start. 0he he%i* an'%e of a worm is not usua%%y specifi ed. ;nstead+ the %ead an'%e+ which is e)ua% to >: de'rees minus the he%i* an'%e+ is 'iven.
1.4., R(@ 5 <*5*5
F*61.- R(@ 5 <*5*5 6'&*56
A rack is a toothed bar or rod that can be thou'ht of as a sector 'ear with an infinite%y %ar'e radius of curvature. 0or)ue can be converted to %inear force by meshin' a rack with a pinion@ the pinion turns the rack moves in a strai'ht %ine. #uch a mechanism is used in automobi%es to convert the rotation of the steerin' whee% into the %efttori'ht motion of the tie rod(s". Racks a%so feature in the theory of 'ear 'eometry+ where+ for instance+ the tooth shape of an interchan'eab%e set of 'ears may be specified for the rack (infinite radius"+ and the tooth shapes for 'ears of particu%ar actua% radii are then derived from that. 0he rack and pinion 'ear type is a rack rai%way.
1.- N7'5(38?&' 6'&=
10
emp%oyed in
F*6 1. G'& N7'5(38?&' R88*53 &'?'5(;% 5
Measured in rotation over time+ such as RPM. A56?3& &'?'5(;%
Measured in radiansEsecond. 1 RPMH IE3: radEsecond N?7>'& 8''8)% N
-ow many teeth a 'ear has+ an inte'er. ;n the case of worms+ it is the number of thread starts that the worm has. P*5*5
0he sma%%er of two interactin' 'ears. P8) (58(8
Path fo%%owed by the point of contact between two meshin' 'ear teeth. P&'==?&' 3*5'
?ine a%on' which the force between two meshin' 'ear teeth is directed. ;n 'enera%+ the %ine of action chan'es from moment to moment durin' the period of en'a'ement of a pair of teeth. =or invo%ute 'ears+ however+ the toothtotooth force is a%ways directed a%on' the same %ineFthat is+ the %ine of action is constant. 0his imp%ies that for invo%ute 'ears the path of contact is a%so a strai'ht %ine+ coincident with the %ine of contact A*=
11
A*is of revo%ution of the 'ear center %ine of the shaft. P*8() <*58
Point where the %ine of action crosses a %ine joinin' the two 'ear a*es. P*8() (*&(3'
Circ%e centered on and perpendicu%ar to the a*is+ and passin' throu'h the pitch point. A predefined diametric position on the 'ear where the circu%ar tooth thickness+ pressure an'%e and he%i* an'%es are defined. P*8() *7'8'&%
A predefined diametric position on the 'ear where the circu%ar tooth thickness+ pressure an'%e and he%i* an'%es are defined. 0he standard pitch diameter is a basic dimension and cannot be measured+ but is a %ocation where other measurements are made. ;ts va%ue is based on the number of teeth+ the norma% modu%e (or norma% diametric pitch"+ and the he%i* an'%e. ;t is ca%cu%ated as@ d
=
Nm φ
cos
in metric units
M?3' & 7?3?=% 7
#ince it is impractica% to ca%cu%ate circu%ar pitch with irrationa% numbers+ mechanica% en'ineers usua%%y use a sca%in' factor that rep%aces it with a re'u%ar va%ue instead. 0his is known as the modu%e of the whee% and is simp%y defined as m= p / π
here+ m is the modu%e and p the circu%ar pitch. 0he units of modu%e are customari%y mi%%imeters. 0he distance between the two a*es becomes a =m ( z1 + z 2 ) / 2
here JaK is the a*is distance+ B 1 and B2 are the number of co's (teeth" for each of the two whee%s ('ears". 0hese numbers (or at %east one of them" is often chosen amon' primes to create an even contact between every co' of both whee%s+ and thereby avoid unnecessary wear and dama'e. An even uniform 'ear wear is achieved by ensurin' the tooth counts of the two 'ears meshin' to'ether are re%ative%y prime to each other this occurs when the 'reatest common divisor (!C$" of each 'ear tooth count e)ua%s 1+ e.'. !C$(16+25"H1 ;f a 1@1 'ear ratio is desired a re%ative%y prime 'ear may be inserted in between the two 'ears this maintains the 1@1 ratio but 12
reverses the 'ear direction a second re%ative%y prime 'ear cou%d a%so be inserted to restore the ori'ina% rotationa% direction whi%e maintainin' uniform wear with a%% 4 'ears in this case. Mechanic en'ineers at %east in continenta% &urope use the modu%e instead of circu%ar pitch. 0he modu%e+ just %ike the circu%ar pitch+ can be used for a%% types of co's+ not just evo%ved based strai'ht co's. O<'&8*56 <*8() *7'8'&=
$iameters determined from the number of teeth and the center distance at which 'ears operate &*amp%e for pinion@ dw=
2a
u +1
2a =
z2 z1
+1
P*8() =?&('
;n cy%indrica% 'ears+ cy%inder formed by projectin' a pitch circ%e in the a*ia% direction. More 'enera%%y+ the surface formed by the sum of a%% the pitch circ%es as one moves a%on' the a*is. =or beve% 'ears it is a cone.
A563' (8*5
An'%e with verte* at the 'ear center+ one %e' on the point where matin' teeth first make contact+ the other %e' on the point where they disen'a'e. A&( (8*5
#e'ment of a pitch circ%e subtended by the an'%e of action Ѳ. 0he comp%ement of the an'%e between the direction that the teeth e*ert force on each other+ and the %ine joinin' the centers of the two 'ears. =or invo%ute 'ears+ the teeth a%ways e*ert force a%on' the %ine of action+ which+ for invo%ute 'ears+ is a strai'ht %ine and thus+ for invo%ute 'ears+ the pressure an'%e is constant. O?8=*' *7'8'&% D0
$iameter of the 'ear+ measured from the tops of the teeth. R8 *7'8'&
$iameter of the 'ear+ measured at the base of the tooth. A'5?7%
Radia% distance from the pitch surface to the outermost point of the tooth
13
a H ($ $"E2 D''5?7% >
Radia% distance from the depth of the tooth trou'h to the pitch surface. bH ($ root diameter" E2. ?ike hydrau%ic cy%inders+ somethin' forces a piston to move in the desired direction. 0he piston is a disc or cy%inder+ and the piston rod transfers the force it deve%ops to the object to be moved. &n'ineers sometimes prefer to use pneumatics because they are )uieter+ c%eaner+ and do not re)uire %ar'e amounts of space for f%uid stora'e. /ecause the operatin' f%uid is a 'as+ %eaka'e from a pneumatic cy%inder wi%% not drip out and contaminate the surroundin's+ makin' pneumatics more desirab%e where c%ean%iness is a re)uirement. =or e*amp%e+ in the mechanica% puppets of the $isney 0iki Room+ pneumatics are used to prevent f%uid from drippin' onto peop%e be%ow the puppets.
1. T;<'= (;3*5'&= 1..1 S*563'(8*56 (;3*5'&= #in'%e actin' cy%inders (#AC" use the pressure imparted by compressed air to create a drivin' force in one direction (usua%%y out"+ and a sprin' to return to the DhomeD position. More often than not+ this type of cy%inder has %imited e*tension due to the space the compressed sprin' takes up. Another downside to #ACs is that part of the force produced by the cy%inder is %ost as it tries to push a'ainst the sprin'.
1..2 D?>3'(8*56 (;3*5'&= $oub%eactin' cy%inders ($AC" use the force of air to move in both e*tend and retract strokes. 0hey have two ports to a%%ow air in+ one for outstroke and one for instroke. #troke %en'th for this desi'n is not %imited+ however+ the piston rod is more 14
vu%nerab%e to buck%in' and bendin'. Additiona% ca%cu%atio ns shou%d be performed as we%%. O8)'&=
A%thou'h #ACs and $ACs are the most common types of pneumatic cy%inder+ the fo%%owin' types are not particu%ar%y rare •
0hrou'h rod air cy%inders@ pisto n rod e*tend s throu'h both sides of the cy%inder+ a%%owin' for e)ua% forces and speeds on either side.
•
Cushion end air cy%inders@ cy%inders with re'u%ated air e*haust to avoid impacts between the piston rod and the cy%inder end cover.
•
Rotary air cy%inders@ actuators that use air to impart a rotary motion.
•
Rod%ess air cy%inders@ 0hese have no piston rod. 0hey are actuators that use a mechanica% or ma'netic coup%in' to impart force+ typica%%y to a tab%e or other body that moves a%on' the %en'th of the cy%inder body+ but does not e*tend beyond it.
•
0andem air cy%inder@ two cy%inders are assemb%ed in series in order to doub%e the force output.
•
;mpact air cy%inder@ hi'h ve%ocity cy%inders with specia%%y desi'ned end covers that withstand the impact of e*tendin' or retractin' piston rods.
R3'== (;3*5'&=
#ome rod%ess types have a s%ot in the wa%% of the cy%inder that is c%osed off for much of its %en'th by two f%e*ib%e meta% sea%in' bands. 0he inner one prevents air from escapin'+ whi%e the outer one protects the s%ot and inner band. 0he piston is actua%%y a pair of them+ part of a comparative%y %on' assemb %y. 0hey sea% to the bore and inner band at both ends of the assemb%y. /etween the individua% pistons+ however+ are cammin' surfaces that Dpee% offD the bands as the who%e s%idin' assemb%y mov es 15
toward the sea%ed vo%ume+ and Drep%aceD them as the assemb%y moves away from the other end. /etween the cammin' surfaces is part of the movin' assemb%y that protrudes throu'h the s%ot to move the %oad. f course+ this means that the re'ion where the sea%in' bands are not in contact is at atmospheric pressure Another type has cab%es (or a sin'%e cab%e" e*tendin' from both (or one" endLs of the cy%inder. 0he cab%es are jacketed in p%astic (ny%on+ in those referred to"+ which provides a smooth surface that permits sea%in' the cab%es where they pass throu'h the ends of the cy%inder. f course+ a sin'%e cab%e has to be kept in tension. #ti%% others have ma'nets inside the cy%inder+ part of the piston assemb%y+ that pu%% a%on' ma'nets outside the cy%inder wa%%. 0he %atter are carried by the actuator that moves the %oad. 0he cy%inder wa%% is thin+ to ensure that the inner and outer ma'nets are near each other. Mu%tip%e modern hi'hf%u* ma'net 'roups transmit force without disen'a'in' or e*cessive resi%ience. C5=8&?(8*5
$ependin' on the job specification+ there are mu%tip%e forms of body constructions avai%ab%e •
0ie rod cy%inders@ 0he most common cy%inder constructions that can be used in many types of %oads. -as been proven to be the safest form.
•
=%an'edtype cy%inders@ =i*ed f%an'es are added to the ends of cy%inder+ however+ this form of construction is more common in hydrau%ic cy%inder construction.
•
nepiece we%ded cy%inders@ &nds are we%ded or crimped to the tube+ this form is ine*pensive but makes the cy%inder nonserviceab%e.
•
0hreaded end cy%inders@ &nds are screwed onto the tube body. 0he reduction of materia% can weaken the tube and may introduce thread concentricity prob%ems to the system.
16
M8'&*3
Upon job specification+ the materia% may be chosen. Materia% ran'e from nicke%p%ated brass to a%uminum+ and even stee% and stain%ess stee%. $ependin' on the %eve% of %oads+ humidity+ temperature+ and stroke %en'ths specified+ the appropriate materia% may be se%ected.
R =8&'=='=
$ue to the forces actin' on the cy%inder+ the piston rod is the most stressed component and has to be desi'ned to withstand hi'h amounts of bendin'+ tensi%e and compressive forces. $ependin' on how %on' the piston rod is+ stresses can be ca%cu%ated different%y. ;f the rods %en'th is %ess than 1: times the diameter+ then it may be treated as a ri'id body which has compressive or tensi%e forces actin' on it. ;n which case the re%ationship is@ F
=
Aσ
here+ = is the compressive or tensi%e force. A is the crosssectiona% area of the piston rod. N is the stress. -owever+ if the %en'th of the rod e*ceeds the 1: times the va%ue of the diameter+ then the rod needs to be treated as a co%umn and buck%in' needs to be ca%cu%ated as we%%. I5=8&@' 5 O?8=8&@'
A%thou'h the diameter of the piston and the force e*erted by a cy%inder are
re%ated+
they are not direct%y proportiona%to one another. Additiona%%y+ the typica% mathematica% re%ationship between the two assumes that the air supp%y does not become saturated. $ue to the effective cross sectiona% area reduced by the area of the piston rod+ the instroke force is %ess than the outstroke force when both are powered pneumatica%%y and by same supp%y of compressed 'as. 17
0he re%ationship between the force+ radius+ and pressure can derived from simp%e distributed %oad e)uation@ Fr = P A e
here+ =r is the resu%tant force P is the pressure or distributed %oad on the surface Ae is the effective cross sectiona% area the %oad is actin' on O?8=8&@'
Usin' the distributed %oad e)uation provided. Ae can be rep%aced with area of the piston surface where the pressure is actin' on. Fr = P ( π r
2
)
here@ =r represents the resu%tant force 0 represents the radius of the piston I is pi+ appro*imate%y e)ua% to 3.1415>. I5=8&@'
n instroke+ the same re%ationship between force e*erted+ pressure and effective cross sectiona% area app%ies as discussed above for outstroke. -owever+ since the cross sectiona% area is %ess than the piston area the re%ationship between force+ pressure and radius is different. 0he ca%cu%ation isnGt more comp%icated thou'h+ since the effective cross sectiona% area is mere%y that of the piston surface minus the cross sectiona% area of the piston rod.
18
=or instroke+ therefore+ the re%ationship between force e*erted+ pressure+ radius of the piston+ and radius of the piston rod+ is as fo%%ows@
(
2
2
F r = π r 1− π r 2
)= Pπ ( r −r ) 2
2
1
2
here@ F r represents the resu%tant force.
r1 represents the radius of the piston. r2 represents the radius of the piston rod. π
is pi+ appro*imate%y e)ua% to 3.1415>.
A pu%%ey is a whee% on an a*%e or shaft that is desi'ned to support movement and chan'e of direction of a taut cab%e or be%t a%on' its circumference. Pu%%eys are used in a variety of ways to %ift %oads+ app%y forces+ and to transmit power. ;n nautica% conte*ts+ the assemb%y of whee%+ a*%e+ and supportin' she%% is referred to as a Db%ock.D A pu%%ey may a%so be ca%%ed a sheave or drum and may have a 'roove between two f%an'es around its circumference. 0he drive e%ement of a pu%%ey system can be a rope+ cab%e+ be%t+ or chain that runs over the pu%%ey inside the 'roove. -ero of A%e*andria identified the pu%%ey as one of si* simp%e machines used to %ift wei'hts. Pu%%eys are assemb%ed to form a b%ock and tack%e in order to provide mechanica% advanta'e to app%y %ar'e forces. Pu%%eys are a%so assemb%ed as part of be%t and chain drives in order to transmit power from one rotatin' shaft to another.
1. BELT AND PULLEY SYSTEMS
19
F*6 1. F38 >'38 5 >'38
F*6 1./ B'38 5
F*6 1.9 C5' +' >; 3*5' =)8
A be%t and pu%%ey system is characteriBed by two or more pu%%eys in common to a be%t. 0his a%%ows for mechanica% power+ tor)ue+ and speed to be transmitted across a*%es. ;f the pu%%eys are of differin' diameters+ a mechanica% advanta'e is rea%iBed. A be%t drive is ana%o'ous to that of a chain drive+ however a be%t sheave may be smooth (devoid of discrete inter%ockin' members as wou%d be found on a chain sprocket+ spur 'ear+ or timin' be%t" so that the mechanica% advanta'e is appro*imate%y 'iven by the ratio of the pitch diameter of the sheaves on%y+ not fi*ed e*act%y by the ratio of teeth as with 'ears and sprockets. ;n the case of a drumsty%e pu%%ey+ without a 'roove or f%an'es+ the pu%%ey often is s%i'ht%y conve* to keep the f%at be%t centered. ;t is sometimes referred to as a crowned pu%%ey. 0hou'h once wide%y used on factory %ine shafts+ this type of pu%%ey is
20
sti%% found drivin' the rotatin' brush in upri'ht vacuum c%eaners+ in be%t sanders and band saws. A'ricu%tura% tractors bui%t up to the ear%y 1>5:s 'enera%%y had a be%t pu%%ey for a f%at be%t (which is what be%t pu%%ey ma'aBine was named after". ;t has been rep%aced by other mechanisms with more f%e*ibi%ity in methods of use+ such as power takeoff and hydrau%ics. Oust as the diameters of 'ears (and+ correspondin'%y+ their number of teeth" determine a 'ear ratio and thus the speed increases or reductions and the mechanica% advanta'e that they can de%iver+ the diameters of pu%%eys determine those same factors. cone pu%%ey a nd step pu%%eys (which operate on the same princip%e+ a%thou'h the names tend to be app%ied to f%at be%t versions and , be%t versions+ respective%y" are a way to provide mu%tip%e drive ratios in a be%tandpu%%ey system that can be shifted as needed+ just as a transmission provides this function with a 'ear train that can be shifted. , be%t step pu%%eys are the most common way that dri%% presses de%iver a ran'e of spind%e speeds
CHAPTER 2 LITERATURE REVIEW
21
K'*='&
1
disc%oses an e*ercisin' device that emp%oys pneumatics in creatin'
resistance to the muscu%ar force e*erted durin' the e*ercisin' operation. eiserKs pneumatic system inc%udes an e*terna% source of compressed 'as+ such as compressed air+ a reservoir havin' an interna% chamber of adjustab%e capacity connectin' in receivin' re%ation to the 'as from the e*terna% source+ and a means for se%ectin' the vo%ume of the 'as in the reservoir.
C3=@; J &'3
2
disc%oses a 'ravityindependent e*ercise unit desi'ned for
use in micro 'ravity+ or on the 'round+ by hich to counter musc%e atrophy and bone de'radation due to disuse or misuse. Co%oskyKs e*ercise device uti%iBes at %east one modu%ar resistive “pack+ each pack containin' at %east one constant force tor)ue sprin'. &ach tor)ue sprin' is “ound up upon a separate stora'e drum within the pack and each sprin' is attached to a sin'%e output drum. &ach output drum is attached to an output shaft and each output shaft is mechanica%%y connected to a cab%e drum. 0here is a%so a series of mechanica% se%ection devices to se%ect the amount of resistance. 0he unit is compact and of %ow mass. -owever+ the comp%e*ity and number of interna% mechanisms necessary for Co%oskyKs desi'n is %ess than optima%. -ence+ maintenance issues arise+ particu%ar%y in a micro'ravity environment wherein it is undesirab%e to have %ar'e number of interna% parts with the potentia% of these parts around in an unmana'eab%e manner.
B'3
,
disc%oses a usermanipu%ated modu%ar e*ercise machine ith two ree%
assemb%ies+ each inc%udin' a spira%%yound sprin' with app%ies to the rea% a reactive tor)ue of chan'in' ma'nitude as the ree% rotates in response to pu%%in' input forces app%ied to a pu%%cord by the user. A camoperated sprin' compensatin ' mechanism provides for essentia%%y a constant force durin' operations in various e*ercise modes.
CHAPTER , STATEMENT OF PROBLEM 22
=itness is the main concern of the present 'eneration. Machines which we use are of more wei'ht and very cost%y. 0here is an immediate necessity for economica% and %on' %astin' fitness machinery. -u'e wei'hts+ used as force providers today are not on%y increasin' the cost of the e)uipment but a%so increasin' the wear and tear. #o+ usin' a%ternate methods to create the force instead of wei'hts wou%d drastica%%y decrease the cost of the e)uipment. ;n present mode% we rep%ace re'u%ar%y usin' wei'hts by vacuum cy%inders. ;t is possib%e to do different e*ercises. Rep%acin' wei'hts by vacuum cy%inders reduces wear and tear. e can chan'e wei'hts manua%%y as much as we need by chan'in' force actin' position. e can deve%op re)uired amount of force for doin' e*ercise by usin' rack and pinion and fu%crum%ever mechanism. ;n rack and pinion joint we have 'ears and f%ywhee% which deve%op more force for doin' e*ercise. ne of the most advanta'e of the project is that we can use the device even in the Bero 'ravity environment (space". 0his e)uipment can be used in the space by the astronauts for physica% fitness.
CHAPTER 4 METHODOLOGY
23
0he aim of the project is to do mu%tip%e e*ercises in home environment. e are rep%acin' wei'hts with vacuum cy%inders which reduces wear and tear. 0his reduces the cost of the e)uipment. ;n order to rep%icate the presen t e)uipment+ various mechanisms and parts are used to make a compact device. 0he steps re)uired can broad%y c%assified in to fo%%owin' steps@ •
$esi'n of the vacuum cy%inders
•
Rack and pinion mechanism connected to f%ywhee%
•
#crew rod mechanism to adjust the wei'hts ?iftin' rod and c%amp mechanism
•
Pu%%ey mechanism
•
0he machin e to be desi'ned must accomp%ish the above mentioned works with minimum human effort+ time and a%so in the ri'ht se)uence. Many au*i%iary components are inc%uded to different mechanisms. 0he fina% method wi%% be so desi'ned such that it reduces the comp%ications of any previous%y e*istin' desi'ns and provide a re%ative%y cheaper so%ution. 0he various components to be desi'ned bein' interdependent on each other each individua% part must be desi'ned separate%y such that it comes up in so%vin' the prob%ems. A%% the components must be inte'rated in a functiona% manner which a'ain wi%% aid to minimiBe the prob%ems. 0his desi'n process wi%% be e%aborate%y discussed in the comin' sub chapters.
V(??7 (;3*5'&=
R(@ 5 <*5*5 *8) 3;)''3 7'()5*=7 24
R'=*=8*+' ''&(*=' '+*(' L*8*56 & *8) A&7
(37<
7'()5*=7
7'()5*=7
P?33'; ='8?<
F*6 4.1 M'8)36; 4.1 S'?'5(' '=*65 0he se)uence of desi'n p%ays a very important ro%e. #o+ a perfect se)uence with c%ear proof of reason must be estab%ished in order to proceed with the methodo%o'y. T)' ='?'5(' '=*65 5 75?(8?&*56 V(??7 (;3*5'&=
,acuum cy%inders bein' the initia% ori'in part of the methodo%o'y proposed+ it provides the pressure force which is used to do e*ercises. ;t is desi'ned in such a way that the piston cy%inder is connected to the rack and pinion mechanism. R(@ 5 <*5*5 7'()5*=7 *8) 3;)''3
0he rack is connected to the vacuum cy%inders pistons and with the he%p of the pinion shafts and 'ears are connected from shafts to the other f%ywhee% shaft and thus the f%ywhee% is rotated. S(&' & 7'()5*=7
0he screw rod are connected to the rack with the he%p of bearin's and thus with the he%p of nuts the screw rod are rotated and thus wei'hts can be adjusted. ?iftin' rod and c%amp mechanism 0he %iftin' rod is connected to the wishbone arm with the he%p of the c%amp mechanism. 0he c%amp mechanism is used to adjust the %en'ths at different hei'hts. P?33'; 7'()5*=7
0he pu%%ey setup is arran'ed at the bottom of the e)uipment such a way that the cy%inder piston is connected 'ym wire and is used to different e*ercises. 25
4.1.1 V(??7 (;3*5'&= 0he vacuum cy%inders mechanism is the main re)uirement of the present e)uipment it is desi'ned and fi*ed at the top of the e)uipment attached to the frame. R'?*&'7'58
0he cy%inders are re)uired with hi'h pressu re and without the %eaka'e. ;t shou%d be doub%e actin' and have more compact and easy movement with %ess wear and tear. B=*( I'
0he basic idea is to fi* the vacuum cy%inders at the top of the main frame. 0he piston are connected to the rack. #o that the capacity of the cy%inders shou%d be hi'h. 0he pressure taken in the cy%inders are 1Mp and stroke %en'th is 16:mm.
4.1.2 R(@ 5 <*5*5 7'()5*=7 *8) 3;)''3 R'?*&'7'58
0he rack and pinion mechanism is used to ba%ance the forces and a%so to provide e*tra force to the %iftin' person. 0he movement of the f%ywhee% is the main thin' to produce e*tra force. B=*( *'
0he basic idea of this mechanism is to rotate the f%ywhee%. 0o rotate the f%ywhee% 'ears and rack and pinion is used. 0he rack is connected to sma%% 'ears and then the shaft connected to the 'ears is connected bi''er 'ear which is connected to the other shaft which is connected to the f%ywhee% thus the f%ywhee% is rotated.
4.1., S(&' & 5
0he screw rod mechanism is used to adjust the wei'hts such a way that cy%inders positions can be moved and thus the forces are chan'ed. 0he pu%%ey set up is used to do arm e*ercises which is fi*ed at the bottom. B=*( *'
0he basic idea of the mechanism is the screw rods are connected with rack with the he%p of the bearin's and thus with the he%p of the bo%ts which is connected to the main arm such that the movement of screw rod with hand%e moves the vacuum cy%inder 0he pu%%ey setup is such a way that the piston cy%inder is connected to the 'ym wire which is connected to the hand%e which is used to pu%% with hands and used to do different e*ercises. 26
CHAPTER EXPERIMENTAL WORK -.1 I58&?(8*5 Materia% science and en'ineerin' p%ays a vita% ro%e in the modern a'e of science and techno%o'y. ,arious kinds of materia%s are used in industry+ housin'+ 27
a'ricu%ture+ transportation+ etc.+ to meet the p%ant and individua% re)uirements. 0he rapid deve%opment in the fie%d of )uantum theory of so%ids have opened vast opportunities for better understandin' and uti%iBation of various materia%s.
-.2 S'3'(8*5 78'&*3 0he various factors which determine the choice of materia%s are discussed be%ow. -.2.1 P&<'&8*'=
0he materia% se%ected must possess the necessary properties for the proposed app%ication. 0he various re)uirement to satisfied %ow wei'ht+ surface finish+ ri'idity+ abi%ity to withstand environmenta% attack form chemica%s+ service %ife+ re%iabi%ity etc. 0he fo%%owin' four types of princip%e properties of materia% decisive%y affect their se%ection a. Physica% b. Mechanica% c. =rom manufacturin' point of view d. Chemica% 0he various physica% properties concerned are me%tin' point+ therma% conductivity+ specific heat+ coefficient of therma% e*pansion+ specific 'ravity+ e%ectrica% conductivity+ ma'netic purposes etc+ 0he various mechanica% properties concerned are stren'th in tensi%e+ compressive shear+ bendin' torsion and buck%in' %oad+ fati'ue resistance+ impact resistance+ e%astic %imit+ endurance %imit and modu%us of e%asticity+ wear resistance and s%idin' properties. 0he various properties concerned from the+ manufacturin' point of view are+ 1. Cast abi%ity 2. e%d abi%ity 3. /ras abi%ity 4. #urface properties 5. #hrinka'e 6. $eep drawin' -.2.2 M5?(8?&*56 (=8
28
#ometimes the demand for %owest possib%e manufacturin' cost or surface )ua%ities obtainab%e by the app%ication of suitab%e coatin' substances may demand the use of specia% materia%s. -.2., ?3*8;
0his 'enera%%y affects the manufacturin' process and u%timate%y the materia%. =or e*amp%e+ it wou%d never be desirab%e to 'o castin' of a %ess number of components which can be fabricated much more economica%%y by or hand for'in' the stee%. -.2.4 A+*3>*3*8; 78'&*3
#ome materia%s may be scare of in short supp%y. ;t then becomes ob%i'atory for the desi'ner to use some other materia%s which thou'h may be not a perfect substitute for the materia% desi'ned. 0he de%ivery of materia%s and the de%ivery date of the product shou%d a%so be kept in mind. -.2.- S<(' (5=*'&8*5
#ometimes hi'h stren'th materia% has to be se%ected because the forces invo%ved are hi'h and space %imitations are there. -.2. C=8
As %ike any other prob%em+ in se%ection of the cost of materia% p%ays an important part and shou%d not be i'nored.
-., W'*6)8 (3(?38*5 ;nitia%%y the tota% %en'ths of arm and cy%inder shou%d be known 0he tota% %en'th of arm H 55:mm $ivide the tota% %en'th of arm into 5 parts H 55:E5H11:mm Mark the points on the arm with difference of 11:mm Ma*imum pressure H 1MPa 0he tota% stroke %en'th H16:mm hen the arm %en'th is moved the stroke %en'th of cy%inder decreas es and so the vo%ume chan'es with chan'in' in force #o the chan'e in %en'th at ma*imum to minimum points is 3:mm+ 2:mm+ 1:mm #o initia%%y the tota% force H pressure * area Area H A = π r
2
e have boreH5:mm so radius H25mm
29
0ota% force H 1*1:Q6 * ,o%ume ¿ π r
2
(
−3
πx 25 x 10
)
2
H1>6.34> 9
?
H I * (25*1:
Q3
"Q2 * 16:*1:Q3
,o%ume H 3.1*1:Q4m3 e know P1Ep2 Hv1Ev2 ,2 for %en'th of 12:mm ,2H2.3 * 1:Q4 #o we have re%ation+ p1Ep2H v1Ev2+ take v1 H3.1*1:Q4 1*1:Q6Ep2H1.3 P2H741>35.4 9EmQ2 =orce Hp2* area #o force =2H145.6789 #o fHm' so where mH mass+ 'Hacce%eration due 'ravityH>.8mEs 2 H145.678E>.8 H14.8k' #o tota% ma*imum wei'ht H14.8k' #imi%ar%y findin' the vo%ume of+ v3H1.76 * 1:Q4 m3+ v4H1.37*1:Q4 m3+ v5H1.17*1:Q3 m3 And pressures+ p3H567741.8 pa+ p4H441>35.3pa+ p5H37741>.1>pa #o forces we are 'ettin' are+ =3H111.4759+=4H867.79+=5H741.:59 #o wei'hts are H11.37k'+ 8.2k'+ 7.5k'
-.4 D'=*65 30
F*6 -.1 B=*( '=*65
e desi'ned the shape of the device such a way that cy%inders wi%% be fi*ed to the top of the frame and %iftin' arm wi%% be connected to the cy%inders in such a way that easy to do the e*ercises. 0he pu%%ey set up is attached down of frame such that the re)uired e*ercise can be done. 0he f%ywhee% setup is fi*ed to the cy%inders on rack and pinion set up to 'et perfect mechanism.
31
F*6 -.2 &58 +*'
Cy%inders and f%ywhee% set up is p%aced at the top of the frame tota% setup. 0he %iftin' arm is fi*ed wishbone arm and is desi'ned to hand%e easi%y.
F*6 -., =*' +*'
32
0he set up fi*ed with bo%ts and nuts. 0he wishborn arm is fi*ed to the frame by nuts and bo%ts.0he pu%%ey setup is fi*ed at the bottom.
F*6 -.4 8< +*'
0he top view shows e*act %ocation of wishborn arm and %iftin' arm.0he frame a%so Attached perfect%y and the support base at the down is attached to the frame.
33
-.- C7<5'58= &'=*=8*+' ''&(*=' '+*(' T>3' -.1 C7<5'58= &'=*=8*+' ''&(*=' '+*('
S.NO
PART NAME
UANTITY
1
/A#& =RAM&
1
2
MA;9 =RAM&
1
3
,ACCUM C?;9$&R#
4
!&AR#
6
5
=?-&&?#
2
6
RAC#
2
7
;R9 P?A0&#
2
8
!&AR #-A=0#
2
>
#CR& R$#
2
1:
/&AR;9!#
4
11
PU??&#
2
12
!M ;R&
1
13
9U0#A9$/?0#
A# MA9 R&
14
;R9 P;P&
2
15
ARM
3
2
34
-. S<'(**(8*5= T>3' -.2 S<'(**(8*5= S.NO
PART NAME
SPECIFICATION
1
#
2
RU9$P;P&
3
,ACUUMC?;9$&R#
4
!&AR
6mm $;A
5
!&AR#
8mm $;A
6
=?-&&?#
$;A 15mm
7
RAC#
35:mm
8
;R9 P?A0&#
>
!&AR #-A=0#
35:mm
1:
#CR& R$#
55:mm
11
/A?? /&AR;9!#
12
PU??&
1::mm
13
PU??&
5:mm
14
!M ;R&
15
9U0#A9$/?0#
16
;R9 P;P&
35=&&0 5=&&0
#MC16:
37:mm*1::mm
#=62:2
2::mm A# MA9 R&
35
-..1 V(??7 (;3*5'& =<'(**(8*5= T>3' -., V(??7 (;3*5'& =<'(**(8*5=
M&$;UM
CMPR&##&$A;R+99?U/R;CA90
P&RA0;9! PR&##UR&
:.5 0 1: bar
AC0;9
$U/?&
/R&
5:mm
#0R&
16:mm
$;M&9#;9#
33>*65*65mm
/ARR&?#
A9$;S&$A?UM;9;UMPR=;?&
P;#09R$
-AR$C-RM&$#0&&?
36
-. F>&*(8*5
F*6 -.- 7*5 &7'
F*6 -. L*8*56 &
•
0he fabrication of main frame work is done
•
0he wishbone arm is done and is attached to the main frame
•
0he vacuum cy%inders are we%ded with supportin' parts and the bo%ts and nuts
F*6 -. +(??7 (;3*5'&=
are fi*ed and it is to be fi*ed to the frame. 0hus the cy%inders position is to be fi*ed
37
F*6 -./ (;3*5'& <*=85 *8) &(@ •
0he fi*in' of vacuum cy%inders is done to the frame with the he%p of joints and bo%ts and nuts.
•
0he cy%inder pistons are connected to the rack with the he%p of arc we%din'
F*6 -.9 3;)''3 ='8 ?< 5 7*5 &7 •
0he 'ears are attached to the frame with the he%p of shafts and two p%ates are attached at the midd%e of the racks. -ere the rack is drive the sma%% 'ear and the shaft which is attached to it rotates so the bi''er 'ear attached to the same 38
shaft rotates and the it drives the other sma%%er 'ear and the shaft attached to it is connected to the f%ywhee% and thus the f%ywhee% rotates •
0he racks are attached to main arm with the he%p of screw rod and the same screw is attached to another screw rod and it is connected to the hand%e. hen the hand%e rotates the screw rod rotates and thus rack screw is moved on the arm
F*6 -.10 (37< :?=87'58 •
0he %iftin' rod adjustin' mechanism is made. ;n this the c%amp is made such a way that it can be adjusted in the different positions. 0he %iftin' rod is connected to the c%amp on other side. 0hus %iftin' rod can be adjusted with re)uired position. At the down bearin' is connected so that it can be moved in rotationa% direction
F*6 -.11
39
•
0he pu%%ey set up is attached at the bottom of the main frame with two pu%%eys and one cy%inder at 'ym wire which is connected the piston cy%inder and moved on the pu%%eys.
F*6 -.12 *53 =='7>3' 5 *5*=)' <&?(8 •
0he tota% assemb%ed and finishe d part of resistive e*ercise device is done and the mu%tip%e e*ercises can be done and it can be easi%y hand%ed.
40
-./ C5=8&?(8*5 0he resistive e*ercise device invo%ves vacuum cy%inders+ rack and pinions+ 'ears+ f%ywhee%s+ screw rods+ main arm+ wishbone arm+ and %iftin' rod. 0he cy%inders are connected to the main arm via rack and pinion mechanism. 0ota% si* 'ears are used to transfer the drive to the f%ywhee% from rack. 0he pinion 'ear rotates the id%e 'ear which drive the 'ear that is connected to the f%ywhee%. 0he main arm contains screw rods that are connected to rack. 0he main arm is connected to the wishbone arm. 0he wishbone arm is a'ain connected to %iftin' rod with adjustin' c%amp mechanism. ne more vacuum cy%inder is attached at top of base frame. 0he cy%inder piston is connected to two pu%%eys with the he%p of 'ym wire which moves on the pu%%eys. 0he wire is connected to the hand%e which is pu%%ed durin' e*ercise.
-.9 W&@*56 hen the %iftin' rod is %ifted the wishbone arm moves the main arm+ so the rack is moved. 0he piston cy%inder moves up and down creatin' vacuum pressure inside the vacuum cy%inder. 0he rack is connected to the 'ears so that the motion of the rack rotates the 'ears. 0he 'ears are connected to interre%ate the shafts. 0he shaft is connected to the f%ywhee% so that when the 'ears are rotated the f%ywhee% attached to the shaft is a%so rotated creatin' e*tra resistive force to the person who is %iftin' the rod. 0he main arm contains the screw rods which are connected to the hand%e so that when the hand%e is rotated the screw rod rotates and chan'es the %en'th. /y adjustin' the %en'th the wei'hts can be chan'ed. 0he c%ampin' mechanism at the %iftin' rod he%ps to adjust the hei'ht of %iftin' rod. 0he vacuum cy%inder which is attached at the top of the base is connected to the 'ym wire. hen the wire is pu%%ed the cy%inder piston is moved down and pu%%ed back due to vacuum force .0hus this he%ps to do arm and back e*ercise.
41
-.10 C=8 '=8*78*5 8>3' T>3' -.4 C=8 '=8*78*5 8>3' #.9
PAR09AM&
AMU90
1
1
#
2:::
2
=?A0 R$
3
,ACUUMC?;9$&R#
4
,ACUUM C?;9$&R
4
!&AR#
6
15::
5
=?-&&?#
2
6::
6
RAC#
2
3::
7
;R9 P?A0&#
2
3::
8
!&AR #-A=0#
2
25:
>
#CR& R$#
2
3::
1:
/&AR;9!#
4
35:
11
PU??&#
2
4::
12
!M ;R&
13
9U0#A9$/?0#
14
;R9 P;P&
15
00A?
1
7::
2
1
36:: 6::
1
1:: A# MA9
4::
R&
3:: 11+78:
L>?& (=8
=or the comp%etion of our project we had to 'o for %athe+ dri%%in'+ we%din' and cuttin' and thus we paid for mentioned work to the %abours. verhead char'es@ 42
Rent for workshop
H 1:::Rs
?abourcost
H4::perday
=or15days
H12*4::H48::Rs
Paintin'cost
H3::
#o tota% cost
H materia% cost T%abour cost T overhead cost H 11+68:T48::T1:::T3:: H 17+78:
0ota% cost
H Rs17+78:
CHAPTER RESULTS AND DISCUSSION RESULT 43
•
0he resistive e*ercise device is tested and mu%tip%e e*ercises can be done
•
0he tota% si* e*ercises can be done
•
hen the %istin' rod is fi*ed up of the c%amp then we can do so%der press
•
hen %iftin' rod is fi*ed at the midd%e then we can do s)uad e*ercise
•
hen %iftin' rod is fi*ed down and c%amp is rotated down then bar bi%% row can be done or it is a%so ca%%ed %ate musc%e work out.
•
hen the person s%ept on the f%oor then c%amp rotates up then bench press workout can be done
•
At the down of pu%%ey setup by pu%%in' the wire arm and back musc%e work out can be done
•
Ma*imum wei'ht that the e*ercise device can do H14.8k'
DISCUSSION •
0he resistive e*ercise device works with ma*imum output but the rotatin' time for adjustin' hand%e for chan'in' of wei'hts take more time.
•
/y usin' the motor which is attached to screw rod he%ps to rotate so that it takes %ess time to chan'e the wei'hts.
CHAPTER ADVATAGES AND LIMITATIONS 44
ADVANTAGES •
0he cost of the component is very %ess
•
$ifferent type of e*ercises can be done in sin'%e device
•
0he maintenance is very %ow and easy adjustment of %oads.
•
0he main arm and c%ampin' mechanism make the device easy to operate.
•
0he device is used to %ist heavy %oads and a%so easy to hand%e and make it effective and consistent.
•
Used in space for mu%tip%e e*ercises.
LIMITATIONS •
$urin' the chan'in' %oads the time taken to rotate the hand%e is more.
•
Rack and pinion set up moves with hi'h friction and a%so 'ears moves with hi'h friction.
•
hen %oad adjustin' hand%e is rotated the screw rod is rotates producin' ratt%in' sound.
CHAPTER / CONCLUSION 45
•
0his project work has provided us an e*ce%%ent opportunity and e*perience to use our %imited know%ed'e. e 'ained a %ot of practica% know%ed'e re'ardin' p%annin'+ purchasin'+ assemb%in' and machinin' whi%e doin' this project work.
•
0he desi'n and fabrication of resistive e*ercise device is workin' with satisfactory conditions. e are ab%e to understand the difficu%ties in maintainin' the to%erance and a%so )ua%ity. e have used ma*imum of avai%ab%e faci%ities.
•
;n conc%usion remarks of our project work+ %et us add a few more %ines about our impression project work. 0hus we deve%oped a resistive e*ercise device by usin' more techni)ues+ they can be modified and deve%oped accordin' to app%ication.
CHAPTER 9 FUTURE SCOPE
46
•
0he resistive e*ercise device has many app%ications which is very usefu % in further.
•
;t can be wide%y used in space and a%so used on earth.
•
ith usefu% modifications such as usin' motor for screw rod and a%so computeriBed mechanism for ca%cu%atin' no of counts in e*ercise.
•
0he materia%s and other c%ampin' mechanisms can be chan'ed to make it
•
advanced. #eparate arm mechanism for pu%%ey set up can be insta%%ed which connects upper vacuum cy%inder pistons and can 'et more effectiveness.
47
REFERENCES •
eiser+ may 24 1>81+ disc%oses an e*ercise device with pneumatics creatin' resistance to muscu%ar force+ United states patent number 4+257+5>3. Co%osky+16 au'ust 2::1 disc%oses e*ercise device with sprin's that are mechanica%%y connected to a cab%e drum particu%ar%y in micro 'ravity environment+ U.#. patent number >3114.
•
•
/ea%+ ju%y 13 1>>3 disc%oses a user manipu%ated modu%ar e*ercise machine with spira%%y wound sprin's+ U.#. patent number 5226867. Meher C!(2::4"+ &ffective physica% treatment for backpain.journa% rthop c%in
•
north vo% 5+ 9o 1+2::5+ 35(1"@5764. /i'%and / 6 feb 2:::+ Pi%ates incorp orates mind and body. Oourna% -arvard
•
womenKs hea%th watch+ vo% 3+ 9o 5+2::2. Petrofsky O# (1>7>"+ fre)uency and amp%itude ana%ysis of the &M! durin'
•
e*ercise on the bicyc%e. Oourna% of app%ied research. P' no 115. ?ind A.R.(1>7>" the amp%itude of the surface e%ectromyo'ram durin' fati'uin'
•
isometric contraction. Oourna% musc%e nerve+ P' no257264. Pacy PO (1>85" 0he ener'y cost of aerobic e*ercise in =&$ and fasted norma% subjects. Oourna% app%ied physio% occup physio%+P' no 764766.
•
u%kens (1>>2" Automatic variab%e resistive e*ercise system+ U.#. patent number 3638>41 A.
