US1792237A - Bobbin-thrfad pull-off for lock-stitch machines - Google Patents

Description

Feb. 10, 1931- w. N. PARKES- BOBBIN THREAD PULL-OFF FOR LOCK STITCH MACHINES Filed Jan. 15. 1929 2 Sheets-Sheet 1 m s 1 Q A u r and m M y m H W 3 u fi Mn 3 M mm Feb. I), 1931. w M PARKEs 1,792,237

BOBBIN THREAD PULL-OFF FOR LOCK STITCH MACHINES Filed Jan. 15. 1929 2 Sheets-Sheet 2 O 0 II QZZCT amen M301,

FA/Modem y W 9% W I dttoz we William MParkes' Patented Feb. 10, 1931 a UNITED STr- ILLIAM NELSON PARKES, or 'nnoox nyiv, new YORK, nssrenon T0 Tris smene 'mennreo'rnmne COMPANY, ,or-nmziinnrmnnw JERSEY, A COREOB-ATION or JERSEY Roma n-THREAD [PULL-OFF Pontoon-STITCH MAonmns Application filed January 15,.129." Serial-N0. 332,610.

This invention relates to improvements in sewing machines employing rotary looptakers each complemental to a reciprocatory thread-carrying needle in the formation of lock-stitches, the invention being particularly adapted for machines in which a relatively large thread carrying bobbin is contained 7 within a carrier, journaled in the loop-taker and restrained against rotation therewith.

10 p The present invention has for its object to 5 provide for a decided increase in the speed of operation of sewing lnachines of the kind referred to and nevertheless maintaining unitornnty in the character of the stitches pro- 1 duced. Y

In its preferred embodiment, the present improvement comprises a sewing machlne having a vertical-axis loop-taker in which is journaled a bobbin -carrier provided with 20 thread-guiding means for directing the bobbin-thread substantially horizontally; to the throat-plate needle-aperture. The sharp bend thus formed in the bobbin-thread at the lower edge of saidneedle-aperture has a tendency to resist the passage of the needle-thread loop cast oil by the l0optaler. In order toobviate this resistance and thereby permit of a higher speed of operationjof themachlne, a small quantity of thread is drawn ofi the bobbin just before the setting of'eachstltch.

The lead' of the bobbin-thread to the throat-plate being upon the castrofifside of the loop-taker thebobbin-thread is in the present instance pulled off its supply by me tion of the loop-taker. To this end, the rotation-restraining means for the bobbin-car rier is so arranged and the openermecha nism employed for providing. a thread-passage. past said rotation-restraining means is so" timed that a small-quantity of bobbinthread is thereby pulled from'its supply once for each stitch produced Additional means is prov ded fon'pulling a definite quantity ofbobbinethre'ad from its chani'cally oscillating the bobbin-carrierin a' direction opposlte to the dn-ection of rota operation." This additional pull-off means is particularly advantageous in sewing ma chines having a large under-thread bobbin, as it compensates forvarying degrees of-inertia between a full and practically empty bobbin.

To' provide I means, the feed-dog, which isof the lower four-motion type, carries arib or'fiange positioned to engage the bobbin-thread. between the bobbin-carrier, and, throat-plate needle-aperture during the downward or work-disengaging movement of said feeddog next'succeeding the pull-oflf action ofsaid opener mechanism. v

vIn the accompanying drawings, Fig. 1 is av .v1ew in front elevat on and partly 111 sec,-,

tion of the frontend ofla sewing machine containing the present IIDPEQVQCl; ,st1tchstorming mechanism. Fig- 2 is a top plan View of'the loop-takermechanisn and the feeddog, with the" throat-plate and adjacent rites for this additional pull-oft slide-plate of the clotl1-plate removed; Fig.

a View inelevation of the: bobbin ca'rrier on the bobb n-latch s de thereof. Fig. 5 is a top plan View of the'bracket supporting the adjustable stop-finger for the bobbin-carrier.

spective View. of the feed-dog, shown in verted. Fig. 9 is a detail view of the stitchforming mechanism, illustrating the bobbinthread pull-off action ofthe'feed-dogL Referring to the drawings, the present illiprovementsare shown as embodied in a sewing machine having a cloth-plate l, upon which is suitably secured a throataplate 2 and the slide-plates 3 and 4t, disposed at' opposite sidesf of thethroat-plate The sewing ma- -ch1ne, asusual, is prov ded with an overhang 1 ing bracket-M11175. terinmat ngzat its free end in a head 6 in which is j oarnaled afverticallyreciprocatory needle-bar .7 carrying its 3-is asectional View ofthe loop-taker on sul stantlally the line 33 of Fig. 2. -Fig. t is lower end a needle 8. The needle-bar is reciproca-ted' by operative connections with rotary'shaftfi, saidconnections also serving tooperate a takenp 10 in a manner well known and disclosed in, for instance, the U. S. patent to VVJF. Dial et 211., No. 695,915, Mar. 25, 1902. Also carried by the head 6 is a presser-bar ll to which is secured a a similar gear 17 upon the vertically die The shaft 18 is posed loop-taker shaft 18. journaled at'its lower end in a bushing 19 and at its-upper end in a bushing 20, both of which bushings are suitably fixed in vertically alined apertures in the bracket 13. The gears 16 and 17 areproportionedtoimpart two .rotations to the shaft 18 for eachrotation of,

the actuating shaft -15.

Detachably'secured within the tubular upv per end of the shaft 18, for rotation therewith,

is the stub-shaft-21 of the inner loop-taker body 22, which iscupped to receivea bobbincarrier 23. The bobbin-carrier 23 is peripherally provided with an interrupted bearing rib 24 jour'naled in a raceway constituted by a flange25 atthe upper'edge o1 the inner body 22 and a'fiange 26 at the upper edge of the outer'loop-taker b'ody27 secured upon andin peripheral contact withthe inner body v prising a narrow, internal,bobbin-support- 22. It is to be understood that the inner body 22 and the outer body 27' together comprise the loop-taker proper, said outer body being provided with a loop-seizing beak 28' and an oppositely directed loop-discharging spur 29.

The bobbin-carrier 23 is open at its top and is substantiallybottomless, its base com-V ing flange 30. Extending outwardly and upwardly from the bobbin-carrier base is an auxiliaryhook 31 disposed between the inner loop-taker body and the bobbin-carrier, said hook 31 acting to direct toward the bottom of the bobbin-carrier a limb of the needlethread loop initially caught by the nose 32 afforded by one end of the interrupted bearing-rib 24. Sustained upon the flange '30.

within the bobbin-carrier is abobbin 33, which may be of any suitable construction but contains a larger 'quantity'ot' thread than h-as 'been usually employed inhigh speed machines ot' the'present type. p The bobbin L33'is latched against acciden-f tal upward movementout of ,its' carrier'by a bobbin-retainercomprising a spring tongue 34, the free upper end of which'is reversely bent to providea V-shaped lip 35; ha ving its apex directed toward the bobbin-aids and overhanging the oute edge onliof-thebob bin, The inclined upper and under side's o'f the lip 35 provide for readily deflecting the tongue 34' outwardly by the action uponthe removing the same.

lip of a bobbin when manually inserting or The tongue 34 extends upwardly from a base-member which at opposite sides of the tongue is'provided with l apertured ears',,as 36, for the reception of screws, as 37, whereby the retainer-member base is fastened upon the outer side-wall of the bobbin-carrier below its bearing-rib 2.4.

The tongue 34, above its base, extends through a' slot 38 provided in the wall of theibobbincarrier adjacent the bearing-"rib 24, said" slot '38 merging at its upper end into a U-shaped recess 39 opening intotheinterior of the bob- :bin.-carrier to afford clearance for the tongue 3% and its lip 35.

:lieferrmg more particularly to Figs. 3, 4

and 7 ofthedra-wings, it will be observed that the-recess 39is provided in a'flange '40 extending upwardly from the bearing rib 24 above theflange'26 of the loop-taker and'upon the cast-off side thereof. Thefiange 40 adjacent toth'elip 35 terminates in'a stop-shoulder 41 risingafrom a cutaway,"segmental upper edge 42 of the bobbin-carrier which liesbelow the upper side of the bobbinto provide for'convenient access to said bobbin for removal. Intermediate its ends,'the flange 40 is intersected'by' a thread-slit 43 inclined downwardly'in the direction of rotation o'f theloop-taker, through which slit the bobbin-thread .7)

may be readily passed." At its end opposite to the shoulder 41, thefiange 40 is bent outwardly to provide a stop-shoulder-44 extendin'g substantially the width of'the bearing ribglkl. p v V Bridging the thread-slit 43 and secured upon the outer side ofthe'flange 40 by a screw 45 is a bent tension-spring 46 of which the upper edge extends above said flange-and therefore serves as a guard to 'prevent'entrance ofthe needle-thread loop into said slit '43. The free end of the tension-spring 46 terminates in advance ofthe shoulder '44 and bears against the side of the flange with a pressure which may be regulated by an ad- ,justing screw 47 disposed at the same side of the -"thread,-slit 43 as is the securing screw '45.

"Above-the bearing rib 24 and beginning substantially from thenose32 thereof is-an inclinedflange 48 whichser ves to initially direct ajlimb of the needle-thread lo'opover the upper side-o'f-the bobbin. This flange '4'8- t erminates abruptly in a 'shoulder '49 which 52 in position to overlie the loopy-taker beak aslit isenteringthefneedlethread loop. This lug 52 lras a front loopfabutment face 53 e;- tending generally transversely of the length or the fe'ed s'l'otsb'l and disposed iliiectly '2' is provided with "a,

rearward of the needleaperture 50, said abutment face being inclined downwardly in .a'direction toward the lower rear edge of the lug and inclined laterally toward the rear corner of the edge nearest the loop-taker aXis. Furthermore, the lower edge of the lug is in:-

.clined upwardly from the needle-aperture to-' rapidly spread to facilitate thecasting of the.

loop about the bobbin-carrier. The described inclinesof the abutmentface are designed to accommodate the separation of the loop-limbs during the loop-spreading operation and particularly theupward movement of the looplimb cast across the upper side of the bobbin. Upon the side of the needle-aperture directly opposite to the loop-taker side theredisposed groove 54 adapted to receive alimb ,ofthe needle-thread loop and thereby directionally Iprcsent the other limb for entrance by the looptaker beak.

3' Inorder to restrain the bobbin-carrier 23 against-rotation with the, loop-taker, the throat-plate is: additionally provided with a depending stop-lug at the edge nearest the loop-taker axis, :said lug 551being spaced a substantial distance from a line extending transverselyof the throat-plate through the needle-aperture' thereof. This lug 55 is adapted to be engaged by the bobbin-carrier stop-shoulder l, thereby limiting the rotation of 'thebobbin-carrier in one direction. The lug 55=-and shoulder 44 are, intermittently separated to provide clearance for the needle-thread loop, thisbein'g effected by oscillating the bobbin-carrier in a direction oppositeto thedirection of rotation of the loop-taker: To this end, the shoulder 49 of the bobbin-carrieris intermittently engaged by a vibratory opener-finger 56 secured by a screw 57 upon the upper end of a vertically disposed rock-shaft 58 suitably journaled in the bracket 13. Adjustably secured upon the lower end of the rock-shaft, by means of a screw 59, is an arm 60 having a ball-joint "connection at its free end with a pitm'an: 61 55 provided with' a strap 62 embracing an eccentric 63up0n the actuating shaftl5. :As jtheishaft 15 rotates in '0ne-to'one-relationship with the needle-shaft 9, it is evident that the opener-finger is gvibrated oncev only for 0 each heedlesreciprocation. 1 1 ;-The ,Qscillationof the; bobbin-carrier under the 7 action of the opener-finger is limited by a stop-finger 64c positioned to engage, the

bobbin-. 'carrier stop shoulder all The stop- 65 finger 6ft is secured by a screw 65uponthe As the loop-taker beak 28 entersthe loop.

of, the lug 52 is provided with a vertically,

upper end of a post 66frising from'a sup porting bracket67, provided With'a circular opening 68 loosely enteredfbyithe: bushing 20 in wvhich the loop-taker shaft is journaled, This construction provides for ad justnient of the stop-finger 64 about the looptaker axis, the bracket 67 being secured in adjusted position to the bracket 13 by a screw 69 passing through an arcuate slot 70 infthe bracket 67. f v I i l i r r The bobbin-thread bis directedupwardly from the tension-spring 46 and over the laterally extending endof the fiangej lO, i. e.,

over' the shoulder 44:, and thence to the throat-plate needle-aperture in substantially the plane of; the lowerside off the throat-plate. In order to ease the passage of the cast-off needle-thread loop into the needle-aperture 50past the sharp bend in the bobbin-thread at the lower edge of said aperture the operation of the opener- V finger 56 is so timed as to pull off thread from I the bobbin by its action toprovide threadclearance past the stop-lug 55. By spacing the stop-lug 55 a substantial distance from the needle-aperture 50, theLpull-off and.

opener functions may be usefully combined so as-tooccur sufliciently early inthe drawof theneedle thread loop by the take; up 10. v Infa'ct, the pull-off action'oceurs at substantially the timetha't the needlethread loop is dischargedup'on the'loop-taker spur 29 'by thebeak 28; Furthermore," this timing be slightlychangedlto suit different v sewing conditions by loosening the's'c'rew, 5 9

and relatively" adj Listing the rock-shaft 58 v and its actuating arm 60. '5

Additional means is provided foripulling 2 thread from the bobbin33 after the setting of each stitch to insure aujniforin quantity of slack. thread forfl the [succeeding stitch,

of full and comparatively empty bobbins upon the, quality of the stitching produced. To this end, they feed-dog 7l, which is proj-ected through the throat-plate slots 51 for advancing the work, is provided with pulldrawings, engages the' bobbin thread during its downward or work-disengagingnioye- 1 viment following upon the'feed' ofthe work and thereby pulls'i thread from ithe bebbin. The feed-dog 7l-is secured byiscrew'aas 73,

of feeding mechanism, 1 e i y V Vvlnle lhave claimed herein only certa n features of themechanisrn shown in these. 7

comoanying draw ngs having claimed oth ers of said features in separate applications filed Jan. 15,l929,withserial Nfis. f.$32,61l, 332,612, and: 332,613, it; is .to c understood whereby to nullify the varying inertiaeffeots f' .upon a feed-bar 7,4 which may be aaaateaia vany manner ,to inipartf tlieusualfour inotions to the feed'-dog,'comn1on n this type 'claimed in "the tions.

lock-stitches, a bobbin-carrier'journaled in said loop-taker provided with a stop-shoulder, a thread-carrying bobbin positioned Within said carrier, a stop-lug depending from the throat-plate in position to be engaged by said stop-shoulder to prevent rotation of the bobbin-carrier in one direction, said stop-lug being spaced a substantial distance from a line intersecting the throatplate needle-aperturetransversely of the direction of feedof the work, and means for oscillating saidbobbin carrier once only for each needle reciprocation to open a needlethread loop passagejbetween said stop-lug and stop-shoulder and thereby pull thread 'from'saidbobbin. V

2. In a 'sewing'mac'hine having a throatplate provided with a needle-aperture, a reciprocatory needle, a vertical-axis loop-taker performing a multiple of rotations for each reciprocation of the needle, a bobbin-carrier j ournaled in said loop-taker, a thread-carrying bobbin positioned within said' carrier,

bobbin-thread guiding and tensioning means upon the bobbin-carrier in position whereby the pull of the bobbin-thread in'its pass age to the throat-plate needle-aperture tends to rotate the bobbin-carrier in the direction of rotation of the loop-taker, means for re- 1 straining the bobbin-carrieragainst' rotation with the loop-taker, an" opener-finger Jp'ositioned to engage'the"bobbin-carrier to oscillate it inia difr'ection opposite to the direction of rotation of the 'looprt'aker, and means for operating "said "opener fin ger to {oscillate the bobbin carrier in said 'direction once only for each needle reciprocation in timed relation to pull thread from the bobbin-supply before the cast-off needle-thread loop reaches the throat-plate aperture just previous to the setting'of the stitch i g I V 3.- In a sewing fmachine, "a reciprocatory thread-carrying needle, a: take-up, a "rotary loop-taker complemental t o said needleinthe formation of lock-stitches, a bobbin-carrier journaled in saidloop-tak'er, althre'ad-supp'ly within the bobbin carrier, means ffor Vre straining the bobbin-carrier against rotation with the loop-taker, means for pulling thread from said thread-supply before the conipletion of the stitch-setting actionof's'aid takeup, and additional means ,for pullin g thread V from said thread supplyfto vprovide slack "thread for the succeeding stitch.

, 4. In a sewing machine, a reciprocatory thread-carrying needle, a 'needle-threadtakeup, work-feeding mechanism, a rotary looptaker complemental to said needle in theformation of lock-stitches, a bobbin-carrier 'journaled in saidloop-taker, a thread-supply within the bobbin-carrier, means for re straining the bobbin-carrier against rotation with the loop-taker, means for pulling thread from said thread-supply "before the coin-pletion of the stitch Setting action 'of said takeup, andadditional means acting subsequent- 1y to said thread pull-off means and before the work-advancing action of said feeding mechanism for-pulling thread from thebobbin-carrier thread-supply 'to provide slack thread'for the 'succeedingstitch.

5. In a sewing machine having a throatplate provided with a needle-aperture, a

reciprocatory thread-carrying needle, a needle-thread take-up,Work feeding-mechanism,

a rotary loop-taker complement'al to said needle in the formation of lock-stitches, a

bobbin-carrier journaled in said loop-taker, a lower thread-supply within the bobbincarrier, means for restraining s'a'id bobbincarrieragainst rotation with the looptaker, means for opening a threadfpassage past said bobbin-carrier rotation-restraining means and thereby pulling thread'from said 1 thread-supply, and a pull-oil member carried by said feeding mechanism adapted to engage the lower thread leading to'the throatplate needle-aperture to'pull off additional thread from said lower thread-supply.

6. In a sewing machine, a reciprocatory thread-carrying needle, work-feeding mechanism, a vertical-axis rotary loop-taker complementa'l to said needle inthe formation'of lock-stitches, a bobbin-carrier journaled in taker, and a plurality of devices operating independently of each other to pull thread vfrom said thread supply in addition 'to' the action upon the lower lthread'by the advance of the Work under the 'actionof said workfeeding mechanism. V 1

7. In a 'sewing machine having .a throatplate .provided .with Ia needle-aperture, a

fourrmotion feed-dog operatingithroughsaid throat-plate, .a :reciprocatory needle, a vertical-axis rotary loop-taker positionedbelow the plane :of the throat-plate, a 'bobbinwcar- -ri'er' :journaled in :said' loop-taker, means for restraining the bobbimcarri'eragainst rotationwith theloop-taker, a lower-thread sup-' ply within the bobbinecarrier, a threadl i said loop-taker, a thread-supply within the bobbin-carrier, means for restraining the bobbin-carrier against rotationwiththefloopuiding means upon the bobbin-carrier'for directing the lower thread "to' the *throait plate the lower surface oftheEthr'oatplate and at all inli'natioil toth 'e fliftibh' of feed, and a 'ne'edle-aperturein substantially'the plane of V pull-off member carried by said feed-dog for drawing slack thread from said lowerthread supply.

In testimony whereof, I have signed my name to this specification.

WILLIAM NELSON PARKES.

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