Title of Invention

SLIVER CROSS SECTION MEASUREMENT DEVICE, STRUCTURAL PART OF SUCH A DEVICE AND SPINNING MACHINE

Abstract

A silver cross section measurement device on or for a spinning machine having a drawing mechanism, in particular card or drawframe, with a sensor, the output signals of which are a measure of the sliver cross section of at least one fibre sliver, characterized by a compensation device for the compensation of temperature-induced expansions of structural parts of the sliver cross section measurement device, the said expansions effecting the output signals from the sensor.

Full Text

Silver cross section measurement device st;raictural part of such a dcavice and apiruiitig machixxe The invenrion relates to a silver cross section measurement device on or for a spinning machine having a drawing mechanism, in particular card or drawframe, for measuring the sliver cross section of at least one fibres sliver. The invention relates, further more, to a structural part of such a sliver cross section measure-inent device. Laistly, the invention relates to a spinning machine having a drav/ing mechanism, in partiular card or drawframe. In spinning machines, such as cards or drawframes, the axm is to obtain as uniform a textile is material as possible at the respective machine exit. For chis purpose, the spinning machines orten have a regulated draining mechanism, in order, on the basis cf_ sliver cr-oss section fluctuations measured upstream of the drawing mechanism, to activate according to the fluctuations determined drafting members which are arranged one behind the other ±-n the sliv*5r running direct; ion. Tho draf ting msmbex's are f oraied, for example,:?, by a plur ali ty of pairs ot rollers arranged one behind the other, between which che fibre sliver or fihre slivers is ox ara nipped along tiie respective ni.p lir.e, as it is kr.cmn. Since i:he pairs cf rollers have different, circumf erencial speeds increasing in the sliver runi'^ing direction, the fibre composites cor,sisting of one or more fibre slivers is drawn and eqtalized. Also, in most cases, Lo provide a feedback in the closed control loop or to check the equalisation and, if approjoriate, trigger a mc.:chine stop in the ev^^nt of excessive sliLver-count fluctuations, a second sliver cx-oss section measurement device is provided at the exit of the drawing mechanism. Altt.ough various sensing possibilities for determining the slive^r crosi-i section are knov^ri, uiechanical sensing devices have gained by £ar the greatest acceptance. For example, the Rieter drawfraiue RSB-D 30 has a pair of sensiing discs with mutually parallel axes^, OTIB sensing disci being arranged at a' fixed location and the other 3en£jii:.g disc having a moveable-location design. The fixed-location sensing disc has a circxxmf erential groove, whilst the moveable-location sensing disc possesses a circumferential ring v/hich rolls in the ciroTirfif erential groo\-e. The fibre sliver or fibre slivers is or are in this case lad throngh in the gap bet\/een the circun;£.erenT:ial groove and the circumferential ring c£ the roi^ating sensing di£ics, the moveable-location sensing disc being deflected according to the i-nass fluctuations of th^ fibre.^ sliver or fibre slivers . The cox-re£poi>dingiy varying distance bet-^veen the sensing di.scs is detected by a'leasuring the diHi-'-ance between a surface located en the moveable part of the seuising-disc mounting and a fixedly clai'nped indactive sensor. T?te output signal s froit. tho sensor are processed by a processor unit: in order to activate the pairs of rollers of the drawing raechani>*iirrL. This ki::own device hais -he di sadvan c>ige that uncontrollable expansions of thej individual structura.1 parts of Che £ liver cross r.ecticn itit^ai^ureirifnt device vary the-: distance between tiiG r.aid surface and th^ sensor, without the distance bei.vc-en the s^insii^cr discs varying on account of sliver-mass fluctuations. As a result/ the electrical output signal from the sensor is likewise varied and conse-^^uently simulare.^ a variation in the distance between the sending di.^:cs on account of sliver-mass fluctuations. This l^;ad^ tc a faulty illustration of the in:^tantaneous sliver cross -section;-so thc^.t a switch- off device cf the i'-achi ne evei: pot sibly performs an unaath.yi:i2:*=sd shutdown- in pa-rticular, it has h-sGn f ouiid, for example, tbat the mec-Sur€imanr: valines relcit ing to the s liver -thickness ■flucruations^ are significantly different imniediately after the run-up of che machine and. for example^ tv/o boiirs later, whilst the sliver tJiicknesiS is actually the same, Corrssponding problenns ':X1BO . The object of the present invention is tc i.acrease the measurement accuracy in deteri^ining the . sliver cro£=;s section. In the sliver crosB secr.ion rnea£3ure:rient device :tit='nt:ion It .^7^3 r'acognized Lh^^t '^Esentially v^expera tare-induced c^xpansions of s!truc"(.::ral part:-^ of the ^neasureirent d^v'.Lce are responsible for rjio i^aid errors in d^;ciixnu:-ii-ng the sli\"er cross ^ecti on. ThU5:i, in pax :.iculc)r, teiiiperaoure riseti ■we:;.:^ icund in ths first hou-'S a f ter the s tar t-up of tlae irachine. The niea.5ure::Lient valixea relci^.ing to th=^i sliver-thickness f iuctaat.:. ons are cher^iyfore sigTiit icantly different o-U'iiiVTid icLtt'ily after the run-up of :,he machine and, for exa:riple, two hours later, whi le the v..;:,:" vor i.hickness is ^.r:t\:;ally the same. I'ht^ invonticr: 3^:>l^?e^ the probleiti cau oed t:ltex'eby. The adva:n.tag-^s of tihe invent .ion according to its first asv'^^^ct are, in particnlar, that, by v:he detection of thB teiuperature in the syscem or of a variable representing tlie t:eniperatux'e-ind-aced exparisioxi of structiural parts of the sliver cress \,section ^measurement device, and by the - sensing-error -being conxensated by means of the compensation device according to the invention, a higher accuracy in the evaluation of the sliver cross section and its vari ation in time can be achieved. To detect thts ■cenipierature-induced expansions or the temperature itsedf, there being a direct relation between these variables, according to the invention a cor^respondingly designed detection device is used.. v^hich makes it possiiblci, for example via resistance mea»^^rement, to infetr the temperature of the corresponding structural part: a::.d/'cr of the surroundings. In this case^ the aiea^;ured resistance is propert:iona;i. zo the temperaturis. Al t ^;rna L i vely, a temperature- induced indue t ance change can be measured via an inductive coil. In a further alternative; for ex^imple^ a kr.ovjn PTIOO may be used, in order to measure the temperature To corrKiiitt the output Bignals front the at In^ast one 3tT.ni:o:: .:>f the sliver cross section m^asureraent device. accc:irdir.g to the Invention a ccrrec t: ion ...ni t i.^^^ prcvided; which is part of the ccnvipeni^atiori device accor di.ng to the inventi on . Such a correctior: uniz may coraprise either; an analogue circuit and/or a processor unit, the latter preferably being capable of evaluatixic and processing the coirected output ^jignals from the at leaiat one sensor by means of electronica 1 ly v^hored and ret:rievable correcting factors or one or mor^^ cor:recting functions - In a preferred correction uni.t iifipl^m^rtnted by rrjeans of an analogue, circuit/ ,t-he output oE the derection device is conixected to the input of the cox"recrion circuit.. this circuit being. deBignsd in such a vvay that the outp-ut siignai from the sensor is corrected according to at least one- empir-iccilly predeterriilned correcting factor. This at least one correctiag- factor is obtained in the pre-drawing sone, in that, in the case of preferably a plurality of constant sensing-disc distauc^^s, the output-voltage signal from the sensor is mea&ured as a function of the temperature or of the resi stance of t:he detection device. In the simplest instance, in each ca-se two measurement points are detejrrtiined at different teinperatures and a straight lin€! is drawn thr-ough these two voltage measurement points - The correcting factor is obtained by the gradient of each straight lin^^ being determined and preferably by an averaged straight line being calculated from the individual straight ]ines. A mea^aix^e of the temperature dependeiice of the output volt:age of the sensor is therefore obtainevil. If a volt:age/ temperature curve is irieacured only for one spec:ific sensing-disc distance, the sstid averaging its not neces-sary., CurA'-e profiles with iwoxe than two H;eaL5nr Particrslcirly when a processor unic is used, even more complex voltage/teinperaiture prof i. lee c:^rx be corrected more, accurately. Since it iti; not to be assumed that the said cui"^/e proi'1 le x^esults approxixiiately in a straight line, an extrapolation of one or more voltage/temperature curves in the form of one or more characteristic curves or correcting functions can be carried out. S>uch a correctincr function is then preferably filed in an alectronic stcx'e v/hich can be read out by the processor unit i'xi order to correct the uncorrected output signals from the sensor by means of the correcting function. In a simpler variant, even only a single correcting factor may be filed in the store in order to coi-rect the sensor output signals correspondingly. It is likewise also possible, how-ever, to file a plurality of correcting functions in one or more stores^ in order to take into account further parameters in the compensation of temperature or expansion* In a preferred va^riant. the sliver cross section ineasurement device according to the invent ion i.^ des igned vj-i th a f ixed-1 oca t ion and wi th a .moveable'-location seiisixig disc. The inoves.ble-location seniring disc is in this case deflected as a x-ef.^ult of the sliver croEtt: section fluctuations of the at least one fibre sliver running through, these deflections bei:~g detected by a fixed-location inductive sensor. Othtr non-contact sen.^ors may also be used, for example those vmich are based on optical measurement prir.ciples. Zn an alternative initial for'm, . the sliver cross sec:~ ion me,^3uremeji-t device comprises at least one inoveable-location sensing tongue and one fixed-locat:ior. cour tersurf ace, at least one fibre_:__.r.-sliver running thrc ugh betv/een the sensing tongue and the cour. tersurf ace, and, at the same time, the zuoveable-location sensing tongue px'essed against the at least one fibre sliver being deflected according to the luass fluccuations of the said fibre sliver. The invention according to rhe^ second aspect: is dist inguished in that at least one ^structural pax:t of whe sliver cross section measurement device i^ inanL\factured at least partially from a steel having low thermal steel amounting, at the customary operating t^Jtuperatiires of textile raachineS/ preferably to approximately 1/5 and particularly preferably —^O^-approxiirately 1 /10 of the thermal e>cpansion of steels otherwise used in spinning machines for purposes of this kind. By means of thi3 measure accorcttag to the invention, an expansion of structural parts of the sliver cross seiction me-asurement device can be reduced in such a way that che said di stance btitween the r:ieasureire::it surface and the indvu:tive sensor scarcely changes as a conseq-aence of temperature - Measurement falsifications due .to temperature influences and to the aceompany 1 ng ercpansion of st:mctura 1 parts are thereby effectively red\iced. In 3 preferxed emoodiment, Ni3G [^>L:eGl, as 11 i.^t kj^.o-^'ii, Lis used for tho Btri::cturdl paiv according co the invention, that is to say a ste^^l which ha-^; a. nickel traction of approxi xuately 35-37% nickel and contains Bina-ller cniantj ties of other mecals^ and carbon. The coefficie::>t of ^::Xpar:sion at 2 0^C i^^ approxiioatt^ly :^ero for a steel of thiv^ type. Such .=i steel is known, for example,, by the naiae of Invv.r® stesl. Other comparable steels have ether tr.nd^ TMn^es. N'i3 6 ir^te^als are distinguished by a virtually negligible thermal ex£)an£ion and, jiioreover, are relatively elastic, as compared '^'ith ceramic, tiiat is to say do not Iiave the brittlene;:5S and therefo::e suBcopi:ib;_licy of tlie latter. l7-i particular, it has proved suitable to use nteels of this type as materiai for the sensijig discs of a sliver cross section measureiaent device. It is also perfectly conceivable ro manufacture al 1 the euitable s truetural parts of a sliver cro£>3 section mv^c.sure2t:ent: device from an Ni36" steel or a steel comparable to this. In t;he desigi:!/ likei\d.se dej^cribed {Hibove. of a sliver cross section meac-iurement device v;A th at least or)e 3en£3ing tongue and one countersur Lcuze. i t is likewise advenfeacieous, fcr the ?.iarue reasons ni^sntioned above, to use a steel wi th ].o\v therTr.aj. expans ion and, particularly preferably, Ivi36 steel or a steel comparable to thi&. The invention accordirig to its &&oor,cl aspect can also be t=imployed in the cas& of niiorovvave sensors which may bG used for dstermininci the sliver mass or the sliver fineness and/or the sliver iiioisture at the, entrance emd/or at: the exi t of a texti. 1 e machine having a drav.'ing n.echanism. Sensors oi: this type have a cavity aresonator through which the fibr^. material is led. By th^ irra.diatiori of nticrowaves of varying frequency, the aresonance sicnal is detemined and i a analysed according to frec^aency .sh.Lf t and half-value width-Moi s ture and 5 liver f i n-^r.esi:^ can be de texmined from these vd j ues. At the ^,t^icr ot production of tha m^ichine, the t'^.nipr?reu:uras j.n and cr. the niacriiae are relatively lo\rt?> but ri:^e vrirh t:iTr>{i. In particular, the g*snerat:-Oj:i of heat due to the :na.nhinti' inocors and other .noved (.'oiiiponents and to th^^ fib-^e- sliver friction at the entrance and i-i^xit. of the cavi::y resonacor cause a ^ernperaLurrt rise vhi.ch le^ds cc deiormations of the c:avity-resonator v;slj^ . Such varis^tions in tht:? r esor^a tor geor'.e'iry cause? a i<.h of the resonant f requency car:>e of aj:. unchanged fibre -sliver cross section; ^^nd con^-i^quer^tly ^ tatlsification of the nie.asareruc:ir;t values or le.ad re :viea;i?Mrement inaccura.cies, By contri-ist, the measiireraent accuracy can be increased cons iderably by the resonat-or we^;.l 1 s being produced at least partially fx'om a steel vith low thermal expansion and, in particular, from an Ki36 steel. Such a choice affords the cidvantage chat r.emx:>eratare fluctxiations and coDEv^q-iiently expansions and contractions of ths resrv.iator walls can occur to only a very slight extent. It is therefore uniirtportant, in particular, whether the xtiachine has only just been started up or hias already been in operation for a lengthy period of time. ! l£ niatariaits contrary to the genercition of resonance or CO t:he measurability of the resonant freqfuenc^*' and the damping at this frequency in the cavity of the sensor are used for the resonator walls, its inner walls may be provided with a conductive layer; Such a layer may have a thickness of, for example, 5 fiin, The ii:)veiition likewise embraces a spitoning machine having ai drawing mechanism, in particular a card or a drawfrarr.e, which has temperature cornpensation or temperature corri^ction of the output signals from a sensor of a sliver cross section measureraent device, according to the first aspect of the invention, and/or the use of at least s-ome structural parts v/i th lo\^:' thex'T.al expansion of a :3liver cross seccion measurer-^^nt device; according to the second aspect of the invention. Adx'a atacfeous developmen'~ e o f the invent i on are char?!Cterized by the features of ^:^J.^ subclaims. Th^ invention is explained in more d^tal 1 below v/ith reference to the figures, of, which: ?igare 1 showa a diagrammac:i,caily illufirx ^iued embodi ment: o f a dr a\A? f ra-ne ace o r d i ng L o th«r^ prior art; Figure 2 nhov/s a drav^rframe with ccjiipensati-on devices according to the invention upstream and downstream of the drawing mar^hanism.; Figure 3 £^hov7s a sliver cross sec iiion m.easurerueiLi- device with a compensation device having ^^ processor; unic; and Figure 4 shows a sliv^sr cross section measurement device with a compensation device having an analocjue correction circuir:.. The basic functioning of a drawfranie, as an exairpie of ci. st)inning machine, is explained below with reference to Fig-are 1. Accox'ding to this example from th^ prior art, a plural.ity of essentially non-twisted fibre slivers FB are presented next to one another to the drawframe. It is likewise possible to feed only one f ibx^e s liver FB to the drawframe * Arranged at the entrance of the drawfr-ame is a funnel 12 which condansei^: che fibre slivers FB. Alternatively, other condensing devices may be used- After r^unning through a £:en^ing device 2, 3, described fux^ther below, as part of a sliver cross section rueasurament device 1, the in thi.s case compressed fibre sliver FB' , which consists of trie p":urality ox indiLvidual fibre :^livers FB, is led. into a dx riwing aiechanisiu 4 v/hich forms the core of the drav;fra2ue 10. The dravung mechani3::n 4 has, as a rule^ threes drafting ■r^iembers or pairs of rollers, bel'v;een whic:n Lhe actual draft takes j.ilace. These are the pair of i'eed rollers 5a, 5b. the middle pair of roller ^^ 6i\, 5b ard the pair of wrthdraival or else delivery rol j-'^rs '^c-, 7b: which restate an a o:Lrcuii\f erential ^pe^d incr-^ased in each cas*!) in ':-his order. As ^ result of tiie;^e different: circainferential spt-jeds of the pairs of roll!?rs, the f ibr-3 ^-1 ive:c F3 * is draf ced a.ccording x.o the ratio of the circunaf erencial speeds. The pair oJ: feed rollers Sci, 5b aj^d the middle pair of rollex'S 5a, f5b form in this case what is knov/n as the pre-drafting zone, and the middie pair of rollers 6a, Gb and 'che pair of delivery rollers 7a, 7b form v;hat is l-uiov,n as the main drafting sone. Where Mnreu-ulated dravframes are concerned, during the drafting operation botli the x^^'^-^diaf t and the main draft are constant- Ey contrast, in the case of regaj.ated drawfrarries, regulation takes place by means of a variation in the drafting level. In a regulated drawina mechanism, for this purpose both the px^e-draft and n^airi draft could be varied, but the main draft is almost always selected. The reason is that the main draft is greater than the pre-draft, _so that more accurate regulation can be carried out. Conventionally, a pressjure bar 8 is ' additionally mounted in the main drafting zone, which- deflects the fibre sliver FB' and thus ensures a better guidance of the f ibr^^s, in particular of the fibres not nipped between two pairs of rollers (-^ftrhat are knov.'n as floating fibres). The drafted fibre sliver FB' is cornl^inGd "itfith the aid of an upper deflecting roller 9 and of a nonwoveii funnel 10 and is deposited at a speed v-^ i-a a can IS via a pair of calender rollers 13, 14 and a curved sliver duct 16 which is arranged i.n a turntable 17 rotating at the angular speed CO. To ccjtapensa te th's sliver-mass fluctuations oxi regulated drawnrallies^ the presented fibres slivers norrria.lly ran through a sensing device 2, 3 which precedes the drawLng :nechanism 4 and which consists in the exemplary embodime;.-it; illustrated of two sensing discs 2, 3. The censing device 2,3 is an integral part of a sli^er cras.":5 se.,u.ion measuremer-it device- The sensing disc 2 is of ;:ixed-location design and. has a circumferential groo\^e, in which runs a circuiaf erantial ring of tne sensing disc 3 designed :to be def'lecr.abie perpi^ndicularly i:o it^ axis" :^f"^^rotation_ The fibre sliver F3' i3 guided between the circumferential groove and the c:.rcumferential ring. Since the sensing disc 3 is pressed with pressure against the sensing disc 2^ a measure of the sliver cross section of thi?j fibre sliver FB' ^^an be derived from the deflections .of the sensing disc 3. In a known errbodiment, the sensing di^ic 3 is coupled to an inductive sensox^ (cf., further b^ilow. Figures 3 and 4) , the output signals of v:hich are transminted in the form of electrical voltage signals first to a store 21 which" takes into account '::he path difference or time difference between passing the £>erising device 2, 3 and entry into the drawing mechaninm 4 (FIFO store " Fxrs-i-In-First-Out stor-e) , and then, rafter this time difference has elapsed,.. to-an evaluation and regulating unit 22. The maasuremont signal is accordingly stored inter-mediately i.n the stor-e 21, so that, after a predetermined time or a path covered in a defiTied manner 'oy the fibre sliver FB', the evaluation and regulating unit 22 switches on the regulation which corr.per.sate^ the mass fluctuations by varying the circui-nferent:.al speeds of the middle pair of rollerjp 6a.. 6b and, i i: appropri.ate, of the pair of feed r*oIlers 5a., 5b {;5ee the arrow directions) . The compensation of the ira,^?^:" f lucturjitions in che main drafting zon^. is achiev-'-d. in tht: prt^senc case, by the variation in the rotational spaed of a booster drive 23 ^'hich generates a control rotatJ_cnal speed for an epicyclic; g-^.^r 24. By luean^ of ihi s cont.rol led inicial xcta-ional speed of the ep Lcyciic gear 2 4 into ^A^hich a main motor 2!6 drives, the J.cv;.^r roll-^rs 5a., 6a of the pair of feod rollers Sa, 5b ai:d of the middle ptiir of roll'Srs ca, 6b are driven. The spet^d of the lower roller Ta, driven by the oiain me':.or. ot the pair of delivery i'oilers 7a, 7f= i enic^in:? constant in the praye^;t case and ensures^- exact;!y calonlabj.e production. Fign::e 2 :i llustrates a c'GU\}:o:ioatXf:;:i dv^-'lco 40 i:;.ocoiding to the d.Mven'iiorj v/hich J.s de;^:^.g.:^ed for che coripensaction of temperature -indijcod expand iont; of ermctniral parts of the sliver cross 3ection mea^urernenr: device 1. Teiaperature difference:^ occar duririg the operation of the draw frame, particularly i.n the t irue after the scart-up of the machi.ne vvhen ■:he lat-isr has been at a standstill for a lengthy period o f ti?;Le. The low init..al temper a ti,:re caai^ses 'structural parts of the s 1 i Vo^r c r o s s s e c; t \ on. m'.-2a ^\ir em.-: rra t d e v L C e 1 L o have a lower exg^ansion than at a lacer u:i.iue when the machine has reached operating temperature. In the case of identical s 1 iver cro oS sec LI on r;. 'therefore, at different tempera Lures di f f «srerj t oucput sicinals appear rxx: t-he senior 20/ SO r.xiat laeasurerrx-vrit falsifications cir e unavo i dab 1 e . The cc^rrpeiis & c.i on devi c o 4 Q ac cor ding to the invention is intended to counteract this - In addition, a second coxiipens^ativort device 41 i.^ provided, which is discussed further below. In iihe present exemplary ennbodiin^n'it according to Figure 2; the compenscation device 40 comprises two dete::tion devices 3C. 30' which are designed, for exaiTi;ple, as teniperature seniors (£or example, as PTlO D) . The temperature sensor 3 0 senses the r.emp^^ratu.re cit r^he sensing disc 3 > v/hil£t the tveanp-arafiire censor 30' aKjasiires the tempit^rature at the sensor 2C . Alternai:ive].y, over: only one of the two temp3:Tirat L,2.r-e 5:en.-^ors 3C, 3 0' vnay i>e provided. One or more detection d?^'vices r^^ay also be provided oxi other structur ?i".. parts of the BI iver cr'osE section iriecisurem=;r.. t devi ce 1. Hz ^-^ a j-£:o possible re use det€jction dev Ices i*'or det:ectLng che ajntvient temperature of the 3l:.ver cro:^* seo;:ion rrie^^sureirient device 1. The our.puxs of Lhe te^rperac^.jvc sensors 30, 30' are coi:,:i'?ct ed in each case to ^:zi input of the eva 1 uation and regularin^ unit' 2 2 This .init 2 2 ifi det^igned as a processor unit: or -y-ompri^es such. ^^.Iternacively, u process set. cnit. ;.>epa2:ate irorn the eVc;iuation and xegu!LatinLr unit 22 znay .ilco be used, the output ot which ^^7 preferribJ.y connecte:"! to an input of the unit 22. : in *:he exemplary eraocdinient illustrated according to Fig-lire 2, the ev.^luation and reg-jlating unit 22 pxocr^i'Bes the raea.Eur extent valur^.^. of the temperature sensors 3.:'), 30' by reading out correcting factors or correcting fuiicuions filed in an electronic store 31 and oy correlating uhein both with the meas^urement va lues o f the re:mpera tu re sensors 30, 3 0 * and with the ovirrvoi~ y-A oTia 13 trom the t^ensor 20. The correcting factor or factors or correcting fiinction or funccions are to foe predetermined, in that, in a sixriple instance, ill the case of a constaint distance between the sensing discs 2, 3, the output signals ifrom the' sensor 20 have been measured at different temperatures* The nieaBureinGnt points determined in the case of this constant se^nsing-disc distance are preferably approximated by a function (for exaraple, a straight line) . A correcting funcr.ion can then be produced from this funcr.ion and indicates at which temperature emd at whicti output signal from the sensor which correcting value is to be used for correcting the current output .•^iignal. According to the exeinplary embodiment of Figure 2, this correction takes placfe An the evaluation c.nd tregulatiiig un.it 22. In a more complex xristance, voltage/ temperature measurement series in the case of a plurality of cons cant .diste.nces different from one another are measured, in order to correlate either the decennined measurement values directly or the respective approximation curves with one another. Figure 3 Illustrates in more detail the situation previously described v/ith ref erer.ce to Fi-^ure 2, in particular the relation betvvofiin th^^ sens ina-disc distance and signal gen^rar.ion al: the sensor 20 being illustratt^d^ In this exeirplary erabodirpent, i:he !;-ensing disc 3 is conn^ic ted to a pivor.iriy arm 51 pi vo table abou': an axis of rotation 52 . The pivoting arm 51 carries e. shaft 53 in which a rod 54 is mounted mova]:)ly. The rod 54 carries at one ^nd a target surface 19 ^A^iich is arranged opposite the sensor 20. The rod 54 is connected at its other end to a piston 55 v;hich can be moved back and f or ^:.h in a cy 1 i i\CLt=:-x space 56. A compres sion apr ing 5 7 hav:i.r-g a knovm spr ii:g characteristic acts on the piston 5S. The piston S5 is conn connecting liri^ 58 in such a way Lhat ail the pressure changes in the cylinder space 5 6 which are generated via the seni:;ing-roiler 3/piston 55 connection are damped in such a way that the pressure in the cylinder apace 56 can be maintained at an essentially constant value. The output signals at the sensor 20, then^ are generated in £uch a way that deflections of the sensing disc 3 which are caused by one or more sensed fibre slivers viiry the distance betv/een the carrying surface 19 and the sensor 20 by virtue of the deflection. c£ the pivoting arm 51 on the rod 54. The oxxtput voltage of the inductive sensor 20 is thus also varied. Alternatively/ the sensor 20 may S.1BO be designed, for ex.aitvple, as an optical ^.ensor. Acoo.cding to wha': was Sciid m relation to Figure 2,- tne t.enip^iratures at a Bk^ra^ixig disc (in the present cast^, howe-vez", at i:he sensing d,isc 2) and/or at the sent:or 2 0 are measured. The te^mpersture sensors 30, 30' ufsed for thi^ purpose deliver r/neir measur'Sinenc \a] \ieis to the €iv^l-j.atior:L and processcx' uni t 22 (rsee statements relating to Figv^re 2), T.i\ a siiviplified eifbodiirient, only cne terrij^errAture sensor' is x^?r ovio.ed eic a sens i r:g di GC 2, 3 or ac the sensor 2 0 or at another otx"actural t^ 1 ement or for measuring the ambient temperature. Figu:::e 4 illustrates an altex^nritive comx.^ensation dv^vice 41, reference ber^ng .made to Figure 3 ::or the puri^ose of 'Explanations as to the generatrion of the senior s iQTials. In the exemplary e-nilr-odiTAent illuscraced in Figure 4, an alternative detection device 130 is provided, which is coupled to the sent^ing disc 2. Siich coupling inay, for exarole, ■ have tha appearance of a small metal lie eiertient being connected to the sensing disc 2 and penetrating into an inductive coi 1 of the detecticri device 130, Cori-eBpondingly, the output sicjnal from the detection device 130 variei^, depending OX) t.he expansi on of the sensing disc 2, according to the prevailing teinperature of the sensing disc 2. The output signal from the detection device 130 is transmitted to an analogue correction circuit 25 which, niore^ver, r-eceives the output signals from the sensor 20, The analogue correction ■ circuit 25 is designed in such a way that, according to the output signal from the detection device 130, it-raodi£ies the output signal 20 in such a way that the temperature-induced expa:isioni-s of the respective structural parts of the sliver cross section measurement device 1 are comp-ansated. This compensation likev/ise also includes the size of the output signal from the sensor 20. If, for exainpl*^, the output signal is small, so as to corrtaspond to a sn^all sliver cross fsectioi-a, then, via the analogue correction circuit 25, for example at high temperatures, thiip output: signal 2 0 must be corrected to a greater extent than at low temperatures at which the cor responding structural parts expand to a les;:?er extejin. The relative tesmperatxire-induced error of the sensor 2 0 is therefore greater in the case or •smaller sliv'^r croGs sections than in the case of larger sliver cro3;3 sections, so that,, in; the lattex' instance, the corrt?-Ct i.on :i s Sittci 11 er . ; The cutpu;; signalls from the correctJ.on circuit 25 are subsecruently transmitt^d via: the FIFO stor^ 21 co the evaluation and regulating unit 22 and processed there in a ktlQ^^^rl wav, The embodiments of the invention which are described with reference to the figures are not restricted to the exact arrangement of the i individual sensor;^ and electronic ^units. For example, in the analogue version of Figure 4, the correction ^of the output signals may also follow the store 21. The t::cmpensation according to the invention in terms of temperature-induced errors in the output signal from a i I ^sensor may also be usjed iln : a sliver crojss section raeasurerr.ent device ^hich follows the dra-wing inechanisin .1 " t 4 in Figure 2. Such a islivfer cross section rneasurement device 11 coinprises, for example, the calender rollers • ' ■ i 13, 14, the first of th ' i i a spr-ing 15; according to Figure 2. By ineans of signal transmission^ not illustrated in any iriore dqtail, to a • t ; I ^.ensor 220, the output signals of the latter may be i • I ■ ■ used ageiin for sliver cross section nieasureraent, in ^ i order, in particular, fco ensure adherence to px-edsteriTiined sliver-count values and, if appropriate, to shut down the machine in! the event of fluctuations ! i ^A^hich are .too high, Here,; too, temperatilire-induced ■ ; 1 errors arise which can be compensat.ed according to the invention. Figure 2 illustrv^te:^ that 'she tsmperature at the senior 220 is measured by maaiia or a tempsratura ■ Bens 3r 2 3 0 and tne ifLeasureinent Siignals , from the i temp.^ratare sensor 23 0 and frorTi the sensor 2;20 are fed to an araluCfae correction circuit 226. In this analogue corr.^ctiori circuit 226, the 'output signal cam then be corr-5Cted according to the 'respective tempter ature- induced error by means of one or more pred'^texamined vol tage/ tetiiperatiire cui'ives or voltage/resistance curves. ; Here, coo, \a higher corri^icting value cea\ bo used in the case! of small deflections of the calender roller ][.3 chan in the case of greater:: deflections in which the relative' error d'ae to the temperatux'e-induced ex-pansions of 'structural part;> is lower. ! In c. second aspect of th^; invention, at : least one struct^lral part of a slivosr.,: cross section o^ee^^urenient device is manufactured front! a steel wirh low thermal expatision, A preferred eteel*'ii^; in this case 'NIBD steel (for example. Invar®) or a steel v^hich i.s coniparable to this and which has a very low coefficient of thermal expansion, so that the errors caused by such iei-cj/ansions i i are extremely low and may possibly eveh make it unne i device having the described compensatioxi device ^ ! according to the invention. jit has proved advantageous to :jianufact\ire the sensing .discs 2* 3 &nd/or the . ■ , j ! . calender rollers 13, 14 f roru a steel with low thermal expansion. Alternatively or additionallvi, further structural parts ot.- the respectivt^ sliver cross section ; i meas'ureraent devices 1, 11 rnay consist cf a steel of ■ j this type, for example the i^od 54, the pivotjing ami 51 ; ! and/or the carrying sarface 31 (see Figures 3i and 4). ; i In a verision which is not, : illustrated, one or more resonator w^llls o:^ a rni,crov;'ave reso4iator are itianuEactured at lec;.^^ t partia;lly from a steel wi ch low thenital expanj^ion, The invention can be iaipleraerrzed par ricularly in the case of draw'f rarnes or cards, huL is not restricted to these.. 1. Sliver cross section measurement device (1; 11) on or for a spinning machine saving a drawing mechanism (4) , in particular card or drawframe, with a sensor (20; 220), the output signals of which are mesasure of the sliver cross section of at least one fibre sliver (FB/ FB' ) , charactarised by a compensation device (40; 41) for the compensation of temperature induced expansions of s structural parts of the silver cross section measurement device (1; 1 J.) , the said expansions influencing the output signals from the the sensor (20; 220) . 2 , Measurment device according to claim 1, charactarized in that the compensation device (40,41) comprises a detection device (30, 30', 130) tor the detection of a variable reprasenting the tercperature of rhe sensor surroundings and or cf the sensor '20; 220)- 3. Measturement device according to Claim; 2, charactarized in that the detection device (30, 30' ; 130) comprises a thermocouple, a resistance element an induction ceil, an inductive coil or the like. 4 - Measurment device. according to one of the preceding claims, characterized in that the compsanaation device (40; 4i) cccriprises s correction unit (22, 31; 126; 22 G) for correcting the output signals from the sensor (20; 220). n 5. Measureinent device according to Claim 4, charecterized in that the correction unit {22,; :^1; 126: 226) is designed for correctrng the outp.it sicinal^: froin the sensor (20; 220) by means at least one i predetermined correct inq facror or at; ilfiast ons i f predeterm.Lned correcting function. i : I 1 6. Measurement device accprding to Claini 4 or 5, cjiaracteri^ed in that the coirrecticn -jnit (22/ 31; 126; ! I 22 6) comprises an analogue electrical \ correction, circuit (126; 226)- | ; ! ( ! 7. Measurement device according to oi:e of Clairas 4 zo ^*' charg-ccerized in that the correction iniit (22, 31; 126; 226) comprises a pro^cessor unit (22) and an electronic store (31) . ! i 8. Measurement devi ce according to ; Cl^im 7, chfii'_^c^tei;;;5;Z^ in that r;he : processor unit i 22) is capaole ot processing, ar; iea:;>t one correcting facuor £ile:i in the store (31) or at lea;?t cne cor rec ring f\inc-ion (characteristic curve; fil-^d in ^:he store (31) m order to correct the said iGutjrat signals. 5. Measurement device according t::;; one of Clairas 4 ^c; 5' characterized in that the at l^asz. one correcting/ factor or the at least one correccinH function i-cbtc-iined from an extrapolated curve conr-:!sting ot tv/o cr iTore empirically predetermined neaniiranienc values or a voltage/temperature correlatiorj, the voltage -valuGs cbtalned from the initicil voltage of the sensor (20; 220) containing the error or ihe senic^or (20; 22C; caused by the said structur*al-part expansions. 10. Measurement device according to one of the preceding claims, characterized oy a fixed-location and a moveable-location senfsing: di£>c (2, 3; : 13, 14), betv/isen which the at lear:Jt one: fibre sliver! (FB, r B' ) r-c>n'^. through, the moveable-location sensing^ disc ; 3; 14) toeing deflectable on ^iccount of ; tine mass fluctuations of rhe at least ione fibre sliver^ (PB, FB' ) running through.- ; , 25. Sliver cross section measurement device, substantially as hereinabove described and illustrated with reference to the accompanying drawings.

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557-che-2003 description (complete) granted.pdf

557-che-2003-claims.pdf

557-che-2003-correspondnece-others.pdf

557-che-2003-correspondnece-po.pdf

557-che-2003-description(complete).pdf

557-che-2003-drawings.pdf

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557-che-2003-form 3.pdf

557-che-2003-form 5.pdf

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