5
ANALYSIS AND OPTIMISATION
OF THE NEEDLE TRANSFER MECHANISM
Ja osla Be an
*Ka el Pejcha
**Jiří Komá ek
Technical Uni e si y o Libe ec
Facul y o Mechanical Enginee ing
Depa men o Design o Tex ile Machine
S uden ská 2, 461 17, Libe ec 1, Czech Republic
[email p o ec ed]
*Technical Uni e si y o Libe ec
Facul y o Mechanical Enginee ing
Depa men o Design o Tex ile Machine
S uden ská 2, 461 17, Libe ec 1, Czech Republic
[email p o ec ed]z
**Technical Uni e si y o Libe ec
Facul y o Mechanical Enginee ing
Depa men o Design o Tex ile Machine
S uden ská 2, 461 17, Libe ec 1, Czech Republic
[email p o ec ed]
Abs ac
The pape is conce ned wi h an analysis and op imisa ion o he needle ans e mechanism by
means o he so wa e P o/Enginee Wild i e 4 wi h he aim o educe he noise a high . p.m.
o he machine. The e has been ca ied ou an op imisa ion o selec ed pa ame e s o he
mechanism wi h he aim o a e he ib a ion o he elemen ha con ols he momen o
elease o he needle du ing i s ans e om one needle ba o he o he one. Subsequen ly,
he e is ca ied ou a sensi i i y analysis o he e ec o designing pa ame e s o he mechanism
upon he eloci y o impac o he con olling elemen upon he machine ame. On he basis o
he esul s o he analysis and op imisa ion, he e ha e been p oposed modi ica ions o he
design o he needle ans e mechanism, and subsequen ly, hey ha e been e i ied
expe imen ally by measu ing he sound p essu e on a unc ional model.
1 In oduc ion
The p esen end in he de elopmen o sewing machines is o sho en he sewing imes in he
sewing p ocess and o inc ease he p oduc i i y. O he pa ame e s o he sewing machines
manu ac u ed nowadays a e e.g. silen unning, minimum ib a ions, long se ice li e o
employed mechanisms and easy ope a ion o he machine. The machine, a pa o which is he
needle ans e mechanism, ope a es in he eloci y ange o 100 – 250 . p.m. A highe . p.m.,
he sewing machine p esen s conside able ib a ions and high le els o noise [2]. The objec o
his pape is o analyse he needle ans e mechanism and o op imise i s dynamic beha iou ,
and subsequen ly, o ealise modi ica ions ha should esul in a educ ion o he noise
gene a ed by his mechanism.
6
2 Analysis o he needle ans e mechanism
The needle ans e mechanism ( ig. 1) o ms a pa o he sys em ha allows imi a ing he hand
s i ch. I s ask consis s in p o iding o he ans e o he loa ing needle be ween wo needle
ba s ope a ing abo e he wo k able o he machine and below i . The loa ing needle is
clamped by colle s (i em 12) in he needle ba , owing o he p essing o ce o he sp ings, i ems
11 and 15. The unlocking o colle s is ac ua ed du ing he mo emen o he needle ba by
impac o i s con olling elemen upon he machine ame be o e he dead cen e o needle
ans e , whe e he impac is damped by a ubbe pad (i em 10). The s op block can be seen in
he igu e 2. The jacke o he needle ba (i em 2) goes on mo ing o he lowe dead cen e and
comple es he p ocess o he needle ans e .
A ma hema ical model o he needle ans e mechanism has been de ised by means o he
sys em P o/Enginee Wild i e 4.0 in he module Mechanism. The indi idual pa s o he needle
ans e mechanism a e ep esen ed by means o igid elemen s. The igu e 1 shows he design
o he needle ans e mechanism including wo sp ings. These wo sp ings a e simula ed by
means o he unc ions SPRING and DAMPER. Ano he pliable elemen is he ubbe pad
men ioned abo e al eady. This pad is simula ed by means o he unc ions FORCES and
DAMPER. The mechanism o he needle ba and i s p ope unc ion a e p o ided by a sys em
o s op blocks modelled by means o he unc ion CAM, which allows simula ing impac o
bodies. The coe icien s o es i u ion ha e been adjus ed o such a alue ha he beha iou o
he ma hema ical model would be as close as possible o he beha iou o he eal mechanism
which has been examined by means o a as -speed came a.
F
igu e 1 Sec ional iew o he needle ans e mechanism
F
igu e 2 Newly p oposed c ank mechanism
The needle ans e mechanism pe o ms he ec ilinea e e se mo emen ha has been
ealised by a cam mechanism in he exis ing machine. The newly p oposed unc ional model o
he machine consis s o c ank mechanism wi h se o-d i e con e ing he o a y swinging
mo ion in o ec ilinea e e se mo emen – see igu e 2. In he ollowing diag am 1 he e is
shown he dependence o he posi ion o he needle ba on he ime. The ime alue 0.24 sec.
s op block
7
co esponds o one cycle o he needle mechanism o he machine egime o 250 . p.m. In he
ollowing sec ion, we shall deal wi h he i s passage om he uppe posi ion o he needle ba
o he lowe one, because in his a ea he e exis he highes alues o he accele a ion, and
du ing his mo emen impac s and noise a e gene a ed in pa icula .
The alues o s i ness o he sp ings K1 and K2, i ems 11 and 15, ha e been aken o e om
he wo k [1]. The alues o in insic damping o he sp ings B1 and B2, i ems 11 and 15, and o
in insic damping o he ubbe pad B3 ha e been aken o e om he wo k [3]. The esul ing
alues o s i ness o he sp ings and hei in insic damping a e shown in he able No. 1
below.
Dependency posi ion o needle ba on ime
410
415
420
425
430
435
440
445
450
455
460
465
0 0,03 0,06 0,09 0,12 0,15 0,18 0,21 0,24
ime (s)
posi ion (mm)
D
iag am 1 Dependence o he posi ion o he needle ba on ime
Table 1 Values o s i ness and in insic damping o he sp ings
S i ness K [N/mm] In insic damping B [N.s/mm]
Sp ing i em 11 0,899 0,013152
Sp ing i em 15 0,69 0,03322
Rubbe pad i em 10 - 0,0285
The model comp ises he pliabili y o he ubbe pad. The cou se o he o ce necessa y o he
comp ession o he ubbe pad has been es ablished expe imen ally in he wo k [1]. In he
eco d, he e can be seen he expec ed non-linea beha iou o he ubbe pad du ing i s
comp ession. The cou se o he ac ing o ce has been app oxima ed by a polynomial o hi d
deg ee (1).
246,111,2364,1515693,79)( 23 +++−= xxxxF (1)
Inc eased . p.m. o he machine a e accompanied wi h ib a ions o he con olling elemen o
he needle ba ha con ols he momen o elease o he needle du ing i s ans e om one
needle ba o he o he one. The ib a ions b ing an inc ease o he impac eloci y o he
con olling elemen as a consequence, and hence, an inc ease o kine ic ene gy a he impac on
he machine ame. This phenomenon has an ad e se e ec upon he se ice li e o he pa s,
and na u ally, upon he noise le el o he mechanism. F om he e ec ed analysis he e ollows
ha he exis ing sp ings o he mechanism a e no dimensioned o high . p.m. o he machine
su icien ly. The diag am 2 displays he eloci ies o he jacke o he needle ans e
mechanism and he eloci ies o he con olling elemen o wo di e en egimes. A he
8
ope a ing egimes up o 160 . p.m., he ib a ions o he con olling elemen do no come up
ye , and a he egime 250 . p.m., he di e ence o he eloci ies o he jacke and o he
con olling elemen is ∆ = 0.56m/s. The impac eloci y o he con olling elemen a ains he
alue 2.68m/sec. in his case.
‐2750
‐2500
‐2250
‐2000
‐1750
‐1500
‐1250
‐1000
‐750
‐500
‐250
0
250
500
750
1000
1250
1500
0 0,0025 0,005 0,0075 0,01 0,0125 0,015 0,0175 0,02 0,0225 0,025 0,0275 0,03 0,0325 0,035 0,0375 0,04
Veloci y[mm/s]
Time[s]
Veloci yo  hejacke o needle ans e mechanism(160 .p.m.)
Veloci yo  hecon olelemen (160 .p.m.)
Veloci yo  hejacke o needle ans e mechanism(250 .p.m.)
Veloci yo  hecon olelemen (250 .p.m.)
D
iag am 2 Time beha iou s o eloci ies o he elemen s o he needle ans e mechanism
o he egimes 160 . p.m. and 250 . p.m.
3 Op imisa ion o he s i ness o he sp ing o he ans e mechanism
The ib a ions o he con ol elemen o he ans e mechanism a e in luenced by he s eng h
o he sp ing i em 11 - ig. 1 p ima ily. By inc easing he s i ness o his sp ing, i is possible o
supp ess he ib a ion o he con ol elemen , hus educing he di e ence in eloci ies o he
jacke and o he con ol elemen . Howe e , he p oduced s eng h o he sp ings mus no be
oo high; o he wise, he se o-mo o d i ing he c ank mechanism would ha e o gene a e a
highe o que in he lowe posi ion o he mechanism. By means o a ma hema ical model, he e
has been ound such a alue o sp ing s i ness a which no ib a ions o he con olling
elemen migh occu o he egime 250 .p.m. By he e ec ed sensi i i y analysis he e has
been ound he alue o s i ness o he sp ing i em 11 K1 = 1.235 N/mm. When se ing up his
alue o s i ness, he eloci y o he jacke o he ans e mechanism coincides wi h he
eloci y o he con ol elemen , namely up o he momen o i s impac upon he s op block.
This eloci y is ep esen ed in he diag am 4.
4 Sensi i i y analysis – educ ion o kine ic ene gy o he con ol elemen
An in eg al pa o he needle ans e mechanism is he s op block which p o ides o opening
o he colle s. A e he impac o he ubbe pad upon he s op block, he con olling elemen o
he needle mechanism is b ough o a hal . The kine ic ene gy o he con olling elemen o he
needle ans e mechanism a he d op upon he s op block is de e mined by he ela ion
,
2
12
mEK= (2)
whe e m is he mass o all pa s o he con olling elemen and is he impac eloci y o he
con olling elemen . F om he ela ion i can be seen ha i is possible o educe he kine ic
ene gy h ough a educ ion o he mass, howe e , i is mo e e ec i e o educe he impac
9
eloci y. A educ ion o he eloci y is achie ed by sho ening he leng h o he inne cylinde –
see ig. 3, which o ms a pa o he con olling elemen . Thanks o his al e a ion, he momen
o he impac is ans e ed o an a ea whe e he impac eloci y a ains conside ably lowe
alues – see he diag am 4.
F
igu e 3 Inne cylinde
The able 2 shows he esul s o sensi i i y analysis o he op imised s i ness o he sp ing
i em 11, namely he esul ing alues o he impac eloci y o he con olling elemen and he
alues o kine ic ene gy o indi idual alues o he sho ened g oo e.
Table 2 Table o esul s o sensi i i y analysis – impac eloci y and kine ic ene gy a he
impac
Sho ening o
he g oo e
[mm]
Leng h
o he
pa
[mm]
Leng h o
he g oo e
[mm]
Posi ion o
he g oo e
[mm]
Weigh
[g]
Regime 250 . p.m.
Impac
eloci y [m/s]
Kine ic
ene gy [J]
0 58,8 14,1 24,6 10,60 2,157
0,102826
1 59,8 13,1 25,6 11,15 2,061
0,095043
2 60,8 12,1 26,6 11,7 1,952
0,086303
3 61,8 11,1 27,6 12,24 1,826
0,076422
4 62,8 10,1 28,6 12,79 1,682
0,065622
5 63,8 9,1 29,6 13,34 1,524
0,054511
In he ollowing diag am 3 he e is shown he dec ease o kine ic ene gy due o designing
al e a ion o he inne cylinde in o de o op imise he s i ness o he sp ing, i em 11.
0,04
0,05
0,06
0,07
0,08
0,09
0,1
0,11
00,511,522,533,544,55
Kine icene gy[J]
Sho eningo  heg oo e[mm]
D
iag am 3 Sensi i i y analysis o he e ec o sho ening o he g oo e o he inne cylinde
upon he kine ic ene gy

10
In he diag am 4 he e is shown he ime beha iou o he eloci y o indi idual pa s o he
ans e mechanism o he egime 250 . p. m du ing he mo emen om he uppe posi ion o
he needle mechanism o he lowe one, because he impac o he con olling elemen upon he
s op block occu s in his phase. The blue cu e ep esen s he eloci y o he jacke o he
needle ba o he ans e mechanism – see i em 2, igu e 1. The iole cu e shows he eloci y
o he con olling elemen o he o iginal design wi h o iginal s i ness o he sp ing, i em 11.
The ed cu e ep esen s he eloci y o his elemen o he op imised s i ness alue o he
sp ing, i em 11 K = 1.235 N/mm. The diag am also includes a g een cu e, which s ands o he
modi ied design o he con olling elemen in acco dance wi h he able 2, wi h he g oo e
sho ened by 5mm.
‐2750
‐2500
‐2250
‐2000
‐1750
‐1500
‐1250
‐1000
‐750
‐500
‐250
0
250
500
750
1000
1250
1500
1750
0 0,0025 0,005 0,0075 0,01 0,0125 0,015 0,0175 0,02 0,0225 0,025
Veloci y[mm/s]
Time[s]
Veloci yo  hejacke o needle ans e mechanism
Veloci yo con ollingelemen –op imiseds i nesso  hesp ing
Veloci yo  hecon ollingelemen –modi ieddesign
Veloci yo  hecon ollingelemen –o iginaldesign
D
iag am 4 Kinema ic condi ions o eloci ies o indi idual pa s o he needle ans e
mechanism o he egime 250 . p.m.
The able 3 compa es he alues o kine ic ene gy a he impac o he o iginal needle ans e
mechanism, whe e ib a ions o he con olling elemen occu ed, and o he mechanism wi h
op imised s i ness o he sp ing and modi ied inne cylinde .
Table 3 Reduc ion o kine ic ene gy
Impac eloci y [m/s] Impac ene gy [J]
O iginal mechanism 2,676 0,158261
Op imised mechanism 1,524 0,054511
5 Expe imen al e i ica ion o he op imisa ion o he needle ans e mechanism
The aim o expe imen al measu ing has been a e i ica ion o esul s o he needle ans e
mechanism. Fo his pu pose, he e has been pe o med measu ing o he sound p essu e in he
p oximi y o he needle ans e mechanisms bo h o he o iginal mechanism and o he
op imised one. I has been a compa a i e measu emen , no p e ending o ob ain s anda d
alues o sound p essu e. Fo measu ing he sound p essu e he e has been employed a
measu ing appa a us manu ac u ed by B üel & Kjae wi h he dual-channel analyse 2144 and
mic ophone ype 4165. The ollowing diag am 5 shows he o e all le els o sound p essu e
measu ed on a unc ional model a he egime 250 . p.m. The alue A/L s ands o he o e all
le el gi en by he sum o ene gies in indi idual equencies. The alue W s ands o he o e all
le el weigh ed by he il e A. The il e A is sui able o he analysis o sound p essu e
11
in audible equencies; i espec s he p ope ies o human hea ing. The measu ed esul s and
di e ences in sound p essu es a e summa ised and compa ed in he able 4.
Table 4 Compa ison o o e all le els o sound p essu e
Ope a ing egime 250 . p.m.
O e all le els o sound p essu e (dB) A/L W
O iginal cylinde 105,74 80,8
Modi ied cylinde 102,68 76,4
Reduc ion o o e all le els o he sound p essu e (dB) 3,06 4,4
The esul s o he measu ing con i m a ma ked imp o emen , achie ed by he modi ica ion o
he inne cylinde and op imisa ion o he s i ness o he sp ing. This modi ica ion has b ough
a dec ease o he o e all le el o sound p essu e by 4 dB app oxima ely.
6 Conclusion
In his pape , he e has been analysed he needle ans e mechanism bo h by means o he
so wa e P o/Enginee and expe imen ally. The e has been ca ied ou an op imisa ion o
s i ness o he sp ing o he needle ans e in o de o a e he ib a ions o he con olling
elemen . By means o a ma hema ical model he e has been es ablished he heo e ical eloci y
o he impac o he ubbe pad upon he s op block. The e has been ca ied ou a sensi i i y
analysis o he e ec o he modi ica ion o designing dimensions o he inne cylinde upon he
kine ic ene gy o he con olling elemen a i s impac upon he machine ame. On he basis o
his sensi i i y analysis he e has been al e ed he design o he inne cylinde , and he e has
been e ec ed measu ing o he sound p essu e, which has shown a conside able educ ion. The
expe imen al analysis has also con i med ha he designing al e a ion o he inne cylinde has
exe ed no e ec upon he p ocess o he needle ans e .
12
Li e a u e
[1] PEJCHAR, K.: Analysis and op imisa ion o he dynamic beha iou o sewing machine.
(Diploma wo k). Libe ec, TUL 2008
[2] PEJCHAR, K., BERAN, J., Expe imen al analysis o he mechanisms o sewing machine
(Pape ). Libe ec, TUL 2008
[3] PEJCHAR, K., BERAN, J.: Op imisa ion o he needle ba mechanism. /En y in he
collec ion o pape s/. Libe ec, TUL 2009
P o . Ing. Ja osla Be an, CSc.
Ing. Ka el Pejcha
Ing. Jiří Komá ek
13
ANALÝZA A OPTIMALIZACE MECHANISMU PŘEDÁVÁNÍ JEHLY
Článek pojedná á o analýze a op imalizaci mechanismu předá ání jehly pomocí so wa u
P o/Enginee Wild i e 4 s cílem sníži hluk při ysokých o áčkách s oje. Je p o edena
op imalizace yb aných pa ame ů mechanismu s cílem zamezi kmi ání členu, k e ý řídí
okamžik u olnění jehly při jejím předání z jedné jehelní yče na d uhou. Následně je p o edena
ci li os ní analýza li u kons ukčních pa ame ů mechanismu na ychlos dopadu řídícího
členu na ám s oje. Na základě ýsledků analýzy a op imalizace jsou na ženy kons ukční
úp a y mechanismu předání jehly a následně expe imen álně o ěřeny měřením akus ického
laku na unkčním modelu.
ANALYSE UND OPTIMIERUNG BEIM NADELÜBERGABEWERK
De A ikel behandel die Un e suchung und Op imie ung beim Nadelübe gabewe k mi els de
So wa e P o/Enginee Wild i e 4 mi dem Ziel, den Lä mpegel bei hohe Maschinend ehzahl
zu eduzie en. Es wi d eine Op imie ung de ausgewähl en We kspa ame e o genommen, wo
das Ziel gese z wi d, die Schwingung im Augenblick de Nadellösung bei ih e Übe gabe aus
eine Nadels ange in die ande e s eue nden Glied zu e hinde n. Anschließend olg die
Emp indlichkei sanalyse de Auswi kung on We kskons uk ionspa ame e n au die
Geschwindigkei des S eue gliedein alls au den Maschinen ahmen. Anhand on den
Un e suchungs- und Op imie ungse gebnissen we den Kons uk ionsanpassungen beim
Nadelübe gabewe k en wo en, die anschließend du ch Messung des Schalld ucks beim
unk ions ähigen Modell e suchsmäßig übe p ü we den.
ANALIZA I OPTYMALIZACJA MECHANIZMU PRZEKAZYWANIA
IGŁY
A ykuł jes poświęcony analizie i op ymalizacji mechanizmu p zekazywania igły za pomocą
op og amowania P o/Enginee Wild i e 4, dokonywanej w celu obniżenia hałasu p zy
wysokich ob o ach maszyny. P zep owadzona jes op ymalizacja wyb anych pa ame ów
mechanizmu w celu eliminacji wib acji elemen u, k ó y ok eśla momen zwolnienia igły
podczas jej p zekazywania z jednego p owadnika igły na d ugi. Nas ępnie jes p zep owadzona
analiza w ażliwości wpływu pa ame ów kons ukcyjnych mechanizmu na p ędkość opadania
elemen u s e ującego na amę maszyny. Na pods awie wyników analizy i op ymalizacji
zap oponowano zmiany kons ukcyjne mechanizmu p zekazywania igły, k ó e nas ępnie
ekspe ymen alnie sp awdzono pomia ami ciśnienia akus ycznego na działającym modelu.