US2487988A - Ravelproof seam and method of making the same - Google Patents

Description

Nov. 15 i949 F. F. zEn-:R

RAVEL-PROOF SEAM ND METHOD OF MAKING THE SAME Filed June 8, 1948 NORMA L RELATVELY L/GHT TENS/0N I L nLx/TQ/EE/vson /T NVENTR. W/federz'c F Ze BY ATTORNEY WITNESS Patented Nov. 15, 1949 -:v

RAVEILPR'OOFSEAM ANUMETKHTF Y MAKING THESAME Frederick F.. Zeier,I

The Singer,Manufacturing.l Gompan;

Strateldyonm; assignoretof Elizabeth,.

N. I., a corporation of"New Jersey A Application J une 8, 1948;*-S`er'ial-No.` SLGG'S?` ieolains. (o1. ii-zfasal.

Thissinvention relatestc a ravelfproofseami and-.ae method of; making.` the.- same.-

lnfcenta-in articles ofiwearing apparel, such, for example;A asfovera-lls, dungar-ees and. similar artiolesofi work.. clothing; which:r are given hardv usage.: andesubjected toe thex action of: briers and theflilre;A itfisnot uncommon for the threads of'V thee sewed; seams.v toV loewor-n through or-` broken. These seams: areausually: offA the chain-stitch: variety1 andlwhen a-Hthreadi is ruptured the seam will readily ravele y This inventionshassaszan obect to provide asewedfseamf which; when-onev or more threads: thereof areibroken; wilkbe locked` against ravelling?.

Anotherobj ect= offF the invention is toV provide. animproved;method of making.V a ravel-proof sewediseami.- n

These-:objects/have been attained by=makingfa1 conventional.4 sewed seam ot a needle threadf and a` primary looper.I threadand? simultaneouslyy therewith incorporating in the seam arnaddi-k tionalior auxiliaryvthreadfand sotensioning the auxiliary. threadythatit.E will produce -Y sufficientl friction. on the -loopsf of the other thread;A or threads, tolaind= theeloopsntogetherandfprevent;` the; threadsf from.l ravelling, should! oneor more. ofY the threadsbebrokenr. e

Preferably,but not necessarily; thef auxiliaryI locking; thread. is) relativ-,elylr elastic` (as compared withi the.=otherthreads which" are relatively in1 elastic)y andf,is-.placedf.in =the seam undera tens sionsuicienttocause the. auxiliary threadi to` v contr-act,, if broken,...hut ,not-` sufficient toA causey puckering or shirring of the workpiece. v

The: terms v elastio1 thread? and:A inelastic thread arer-usedi ini this:` specificationina. relative.- sense, the former.loeing;V intended. toindi-Y catef a. thread adaptedrrto he` stretched substanf tiallyiyasforexample, a` nylon or arubber thread;g Whereas the term inelastic thread is intended: tomeana conventional thread of. cotton or the like.Y l

kBrasil-ingsdepicting my improved seam and; ill'ustratineaa` methodl 01E-making. it formI -av part off this disclosure and .in such' drawings Fig. l is a perspective view of. a chain-stitch, seam.4 embodying.` my.. inyention with the: seam mad'efin .theiair ora-part from a.workpiece:v

Eig.M 2.-i's. an under yside.view ofi.A a portionof: a1- workpieceA and, my improved ravelergroof`v seam; therein the. threads; of. thefrseam;v being: shownf. substantially. ini therpositions which? they. occupyl inV an,,unbrokenseam...l

Eig... 3751's. afyvview. similantcbFigf. muti-illustrate. faslwilhbe seemfrormaninspectwnof ing thefsnarling@actionyrof thethreadsiwhicir. takes; placeautomatically; when thef threads.Y of the? seamare broken'.

Fig. 4 is a diagrammatic viewf-ofacertainstitchfV forming; inst-rumentalitiesp-whi'ch may' befused tot make myY improved-f seamf andgalso illustrating: diagramm'atically theY application; of; unequal tensions toA the two. looperfthreadsaz Referring morel snecicallyy to; the); drawings;

-, the.- improved seam issh`ownias1A comprising; an;

upper cir-'needle .thread Ii which isffpassedithrough; the? werkeY W at spaced: intervals, and' formed: into; loon le at-theunder.r side-,ofi` the w,ork. Rassing; through; and surroundingthe; loops le are-louper of a' main: interlockinggor: looper thread; 2.

A-s shownfin-;Eie-'.:4; ,thefthreadse ll' and- .2 arecar.- ried;z respectively, by; afk needlerNland: a;V looperiljl, These threads are relatively inelasticf andi` are;A concatenatedf in the; manner off; azconventional r.xvo+th-i'.eadchain-stitchyseamz; Inf-their travel; from their respective sources'v of.; supply.t to the..

needle N and: thee loopenKV 13,..respectivelmA the@ threads I- and2 2- passqthroughsuitable tension; devices represented.- diagrammatically; in: Fig.' 4;',

as-t and; te respectively.

Cooperating with the threadsnl and;2;.andrcorrv catenatedz with :the former; is; a; th-indor t,auxiliaryv locking threads which-r alsof is; carriech by; the; looperell.-` andA whichf traverses thef same course-.f

asthethread-Zathroughoutthefseam length'` The@ thready 3- isA preferably made. of. nylon. rubber lor." other material'v which isr more elastic than the; material (e. g, co1:onf) -Y of? whichi the: threads; and 2 are made; -Inits:travellltoitheflooper the: thread 3; also /passesffthroug-hi tensioning means shown diagrammatically in@ Eig'. 41; and."

designated generally,V as; 'llhis tensioning meansA appliesfto the'thread: Ssassomewhatigreater; tensionethan: the tension-pwhichA is applied tos the. thread Zrso thatv the thread; 3,1 asfincorporatedt inl' the" seam; exerts: a binding action. onA the: threads,` If and-'2.1 When ther threanri is made. of; rela,- tively: elasticir material; this; ad'diti-onahv tensionicauses f the tlneadz to be` incorporatedf in'thef seam in a stretched condition. The.ten'd'errcyf-ofthel thread.'l Sito; contract,` however;l isV not sufliciently greatgto cause,- pfucliering: of'f'thawork; especiallyYAY whenvsewing: througlir relatively heavy materialk such, as. is used fonmakingr overalls'. and:l other work clothes;J Wshile. the threadid follows the.:

same; generali course: asi .thethread: 2`: throughout. the:seam;- neyerthelessg. duertotwist.: and unequal?A tension; insthe threads, theloeps ofth'e thread frequently; crossioverf tirez-loops .ot-'the thread meer. frm-sy causes a binding of the threads and helps to prevent ravelling of the seam' when the threads are broken, as hereinafter will be described.

The locking thread 3 is preferably materially smaller in cross-sectional area than the looper thread 2. This prevents the seam from being unduly bulky at the under side of the work and yet does not interfere with its function of locking the threads together.

Inasmuch as the tensioned elastic thread 3 frictionally engages both the needle thread I and the looper thread 2, if either or both of those threads should be broken the gripping action of the auxiliary thread 3 will cause the threads l and 2 to be bound together frictionally and thus prevent ravelling of the seam.

Should the elastic thread 3 be broken, either alone or with the threads I and/or 2, contraction of the thread 3 will cause it to snap back and shift the threads comprising the last several stitches of the seam into a malformation, as illustrated atv m in Fig. 3, thereby snarling or tangling the threads, which additionally prevents the seam from being ravelled.

In making this improved ravel-proof seam the needle and looper are threaded with the threads l and 2, respectively, as is customary in twothread chain-stitch sewing machines, the threads passing through suitable tensioning means. In addition, the auxiliary thread 3 is passed through a heavier tension than is the looper thread 2, and also is threaded through the looper, which may have a somewhat enlarged thread groove and thread eyes to accommodate the two threads.

The machine is then operated in the manner common to two-thread chain-stitch sewing machines and produces the above described ravelproof seam.`

It isY recognized that it is not broadly new to sew a seam with a single needle thread and two similar looper threads but, insofar as I am aware, no one heretofore has sewed such a seam in which (a) both looper threads are carried by the same looper and follow the same course throughout the seam length and have materially diierent crosssectional areas; (b) in which one of the looper threads is under greater tension than the other thereby causing the greater tensioned thread to produce a binding elect on the other threads of the seam; or (c) in which that one oi the looper threads which is subjected to the greater tension also has greater elasticity than the other and tends to contract andV snarl the other threads when the elastic thread is broken.

Having thus set forth the nature of the invention, what I claim herein is:

1. A ravel-proof seam comprising an upper thread formed with a plurality of loops projecting through a workpiece at spaced intervals, a lower thread concatenated with the loops of said upper thread at the under side of the workpiece, and a locking thread concatenated with the loops of' said Yupper thread coincident with said lower thread and tensioned to exert a binding action on the other threads.

2. A ravel-proof seam comprising a first thread located at one side of a workpiece and having loops projecting therethrough at spaced intervals, a second thread at the opposite side of the workpiece and having loops concatenated with the loops of said first thread, and a third thread at said opposite side of the workpiece and concatenated with the loops of said iirst thread similarly to and coincident with said second thread, said third thread being more heavily 'tensioned than said second thread and exerting a binding action on the loops of the other threads.

3. A ravel-proof seam comprising a needle thread extending along one face of a workpiece and having a plurality of loops projecting therethrough at spaced intervals, an inelastic looper thread extending along the opposite face of the workpiece and concatenated with the loops of said needle thread, and an elastic looper thread traversing the same course as said inelastic thread and concatenated with the loops of said needle thread, said elastic thread normally being tensioned and stretched in said seam and adapted to contract and snarl the other threads when the elastic thread is broken, thereby to prevent ravelling of the seam.

4. A ravel-proof seam comprising an upper thread formed with a plurality of loops projecting through a workpiece at spaced intervals, a lower thread concatenated with the loops of said upper thread at the under side of the workpiece in a manner common to two-thread chain-stitch seams, and a seam-locking thread concatenated with the loops of said upper thread coincident with said lower thread and tensioned'to exert a binding action on the other threads, said seamlocking thread being materially smaller in crosssection than said lower thread and being twisted thereabout throughout the seam length.

5. A ravel-proof seam comprising a needle thread extending along one face of a workpiece and having a plurality of loops projecting therethrough at spaced intervals, an inelastic looper thread extending along the opposite face of the workpiece and concatenated with the loops of said needle thread, and an elastic locking thread traversing the same course as said looper thread and concatenated with the loops of said needle thread, said elastic locking thread being materially smaller in cross-section than said looper thread and being embodied in said seam in a stretched condition.

6. A ravel-proof seam comprising a rst thread disposed on one face of a workpiece having loops projecting through said workpiece at spaced intervals, a second thread at the opposite side of the workpiece and having loops concatenated with the loops of said first thread, and a third thread at said opposite side of the workpiece and concatenated with the loops of said rst thread, one of said three threads being relatively elastic and normally being tensioned and stretched in said seam and adapted to contract and snarl the other threads when one of said threads is broken.

7. A ravel-proof seam formed in a workpiece and comprising, a rst thread formed at intervals into work-penetrating loops, and unequally tensioned second and third threads concatenated with and anchoring the loops of said rst thread in the work.

8. A ravel-proof seam formed in a workpiece and comprising, a first thread formed at intervals into work-penetrating loops, and unequally tensioned second and third threads of different elasticity concatenated with and anchoring the loops of said first thread in the work.

9. The method of making a ravel-proof seam which comprises successively projecting loops of a thread through a workpiece, concatenating with said loops other loops formed in main and aux-I iliary interlocking threads havingsubstantially iary thread to bind together the loops of the other threads to prevent :ravelling of the seam upon breakage of any one of said threads.

10. The method of making a ravel-proof seam which comprises successively projecting loops of a needle thread through a workpiece at spaced intervals, concatenating with said loops other loops formed in main and auxiliary looper threads, and subjecting said looper threads to unequal tensions whereby the loops of the greater tensioned looper thread exert a gripping action on the needle thread and the other looper thread.

11. The method of making a ravel-proof seam which comprises successively projecting loops of a needle thread through a workpiece at spaced intervals, concatenating with said loops other loops formed in main and auxiliary looper threads, said auxiliary looper thread being relatively elastic, and applying a tension to said auxiliary looper thread to cause it to be embodied in the seam in a stretched condition.

12. The method of making a ravel-proof seam which comprises extending a relatively inelastic thread along the upper face of a workpiece, projecting loops of said thread through a workpiece at spaced intervals, concatenating with said loops at the under side of the workpiece a retaining thread and a locking thread, said retaining and locking threads following substantially the same course throughout the seam but crossing each other at various places along the seam, and applying to said locking thread suicent tension to cause it to bind the loops of the retaining thread against ravelling.

13. The method of making a ravel-proof seam which comprises successively projecting loops of a needle thread through a workpiece at spaced intervals, ccncatenating with said loops other loops formed in main and auxiliary looper threads, one of said threads being relatively elastic, and applying a tension to said relatively elastic thread to cause it to be embodied in the seam in a stretched condition.

FREDERICK F. ZEIER..

No references cited.

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