US2394511A - Lock-stitch sewing machine - Google Patents

Description

Feb. 5,1946. A. B. CLAYTON 2,394,511

LOCK-STITCH SEWING MACHINE Filed Jan. 1, 1945 3 Sheets-Sheet l.

grwa/wiom Feb. 5, 1946. A, CL ,2,394,511

LOCK- STITCH SEWING MACHINE Filed Jan. l, 1945 3 Sheets-Sheet 2 C I) a cflndrezz) l8. Cza yton/ A. B. CLAYTON LOCK-STITCH SEWING MACHINE Feb. 5, 1946.

Filed Jan. 1, 1945 s SheetsShset a WALLQwoo W Patented Feb. 5, 1946 LOCK-STITCH SEWING MACHINE Andrew B. Clayton, Elizabeth, N. J., assignor to The Singer Manufacturing Company, Elizabeth, N. J a corporation of New Jersey Application January 1, 1945, Serial No. 570,926

16 Claims.

This invention relates to lock-stitch sewing machines and it has as a primary object to improve the sewing qualities of such machines, esspecially when operatin at high speeds.

It is well known that many sewing machines which will operate satisfactorily at speeds in the neighborhood of 4,500 stitches per minute, will develop peculiarities and faults, such for example as the skipping of stitches, uneven stitching, irregular feeding and the breaking of thread, when operated at speeds of 5,000 stitches or more per minute. The reasons for these faults or failures are extremely difiicult to discover because of the fact that they do not occur constantly and when they do occur it is at such high speeds and in such inaccessible'places that the particular cause at the time of failure cannot be perceived.

Heretofore, attempts have been made to solve these mysteries of sewing machines by the use of stroboscopes and high speed moving picture cameras, without complete success.

Probably the difficulties inherent in obtaining perfect sewing can best be understood by analyzing the stitch formation of a high speed lock,- stitch sewing machine of the rotary hook type. To make a single lock-stitch, the needle descends through the work and carrie with it the needle thread. As the needle starts to rise, it throws out a loop of needle thread, which loop is entered by the loop-taker beak travellin at a speed of over 650 inches per second. The loop-taker has journaled therein a bobbin-case, carrying a bobbin of lower thread which, in the formation of a 1ockstitch, must be passed, as a mass, through the needle-thread loop. This is efieoted by the loop-taker spreading the needle-loop and passing it bodily around the bobbin-case and the bobbin therein. In conventional sewing machines, this necessitates the passage, through the eye of the needle, of approximately 4 inches of thread. After the loop has been passed about the bobbincase all of the slack thread has to be taken up by pulling the surplus thread 'back through the eye of the needle. This is done by a variable speed take-up mechanism. Thus the cycle for each stitch includes the drawing of approximately 4 inches of thread through the eye of the needle, first in one direction to spread the loop and pass it about the bobbin-case and then in the oppo site direction to take up the slack and set the stitch, thereby causing the passage Of approxi mately 9 inches of thread through the needleeye for each individual stitch. When the ma-- chine is operating at 5,000 stitches per minute, which is not uncommon, 45,000 inches of thread is passed through the needle-eye per minute, (i. e. 750 inches per second) at a varying speed, which reaches a maximum of over 1,700 inches per second when the take-up is moving at its highest speed.

In sewing relatively thin'or light weight material with stitches of medium length, i. e. sixteen stitches to the inch, each particle of thread passes through the needle-eye approximately times (50 down and 50 up) before that particle of thread is incorporated in the seam.

It will readily be understood that this repeated reaving Of the thread back and forth through the eye of the needle, at the high speed at which the thread travels, tends to fray and weaken the thread with the result that any undue strain on the thread, such as may be caused by friction of one thread on the other, or friction of the threads on the work, or on the wall of the needlehole in the throat-plate 0f the machine, can result in breaking of the thread, skipping of stitches, impairment of the seam, or other failure of the machine properly to perform its intended function.

A contributing cause to such failure is the fact that sewing thread is not entirely uniform, varying in both thickness and strength and therefore containing certain weak spots. Also some threads, of the cheaper varieties, contain knotlike slubs which, in passing through the thread tension, place additional strain on the thread, thereby sometimes resulting in thread breakage, especially if the thread has been weakened.

Thread breakage from this cause is proportionate to the amount of tension placed on the thread; the lighter the tension, the more freely will the thread containin the slub pass therethrough, and, therefore, the less will be the thread breakage.

It will also be understood that any undue retardation in the movement of the thread, such as may be caused by excessive friction between the needle and bobbin threads, or between those threads and parts of the sewing machine, such for example as the wall of the needle-hole, will interfere with the proper action of the take-up in setting the stitch and therefore will result in uneven sewing. Such conditions are, of course, exaggerated when a thickened portion of the thread, or a slub, passes through the stitch-forming mechanism.

In conventional high speed lock-stitch sewing machines, the needle reciprocates in a vertical path perpendicular to the upper surface of the throat-plate, through the needle-hole in the thread emerges from the bobbin-case at a point rearwardly of and substantially in the horizontal plane of the axis of rotation of the loop-taker.

From its point of emergence the bobbin threadextends upwardly and'forwardly to the, lowerend of the needle-hole in the throat-plate.

Feed of the work pulls on the bobbin thread and, due to the location of its point of emergence from the bobbin-case, tends to turn the bobbincase and. its carrier-el'ementirr a direction op.- posite; to: the direction of rotation of the: hook; thereby tending to open agap-betweemthe bobbincase carrier elementflandi its: rotation-restraining lug, thus permitting escape of the cast off needle-- loop... as is wellunderstood inthe art. From the upperend .of the needle-hole, the; bobbin thread isdrawnrearwardly by the movement of; the work:

Thus: the: bobbin thread is snubbed about and bears with. considerable pressure against: the rear wall of the needle-hole. During; the formation of. each stitch, the needles-thread loop is required to be: pulled up-between. the bobbin-thread and the wall; of the needle-hole.- about "which the bobbinthread is; snubbed-,; thereby producing a sawing aotiorrv between the threads. The greater thegprese sure of the bobbin-thread on the wall of the needle-hole? the greater will. be thissawing action and; the more likelihoodo-f thread. failure. Also the greater the. resistance: theneedle-thread loop has toovercome in passing between the bobbinthreadandthewall of the needle-hole the greater 7 I will be the; tension required on the needle-thread to insure that the take-up will tighten and setthe stitch withoutstealing thread. from thesupply.

needlerthread tension for. a. given-tension. on the bobbin thread,. will. reduce thread breakage. and

improve. the sewing; qualities. of. the. machine.

This. hasbeen accomplished by. a novel. arrange.- ment of the needle and the. loop-taker relativeto the horizontal. workrsupport of' the machine and to the needle-hole, in the throat-plate.

In accordance. with the preferred, embodiment of the present invention, the axis of. the looptaker is arranged forwardly of the needle-hole. so that the lead of the bobbin-thread extendsmore nearlyvertical to the needle-hole, thereby greatly reducingthe snubbing action of the bobbin-thread about the rearwall of'the needle-hole. Conse quently-thepressure of the 'bobbin-threadjon the wall of the, needle-hole is lessened materially, which facilitates the passage of the needle-thread loo-ptherebetween', with a considerable reduction in the-sawing action: between the threads.

Preferably, the needle-bar and theineedle carried thereby are tipped backwardly'away from the operator so that the needle in its downstroke is inclined downwardly and forwardly, thus mainta-ihing the desirable condition of passingthrough the needle-hole: and directly" toward the axis: of rotationof the; lb-op-tak'er The: needle-thread loop is seized by the loop-taker at a point in the path of the loop-taker beak substantially at one side of the highest point of said beak and while the beak is travelling between its highest and lowest positions.

With the above and other'o-bjects in View, as will hereinafter appear, the invention comprises the devices. combinations andarrangements. of parts hereinafter set forth andiillhstrated; in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby. will: be. readily understood by those skilled in theart,

I'nthe drawings,v

1 is a longitudinal sectional view of a lockstitch sewing machine embodying the present invention...

Fig, 2 is a side elevation of the bracket-arm head of'the machine. V

Fig 3 is: a left. end view' .of:the: machine; illustrated', inv Fig; 1',- with the: faceplate removed;

Fig- 4% is. a. vertical sectional viewtaken: sub;-

stantially onthe line 4-4 ofEig. 1;.

Fig, 5.- is a plan View of the rotary hookof the present. machine showing it, associated with. its rotationerestraining means. I

Fig. 6 isv a. diagrammatic: view illustrating: the imprevedrarrangement. of; the elements of. the stitch-forming mechanism, relativetoieaclr other and to the needle-hole;

Referring, more. specifically to the drawings; the inventionisillustrated as embodied in asewing machinecomprising a base: I, affording a horizontally disposed: work-supporting plate-2 having. a front edge I proximateto the operator, and a rear edge r remotetherefrom Preferably a. portion. 3 of- -the workesupport is removably secured to the main portion. thereof and is. providedwith; a. needle-hole n and slots: s for the passage of a conventional feed-dog d, later to bereferredto. The-portion3is commonly known as. the. .throat-platef of the machine. but for the. purpose of this. disclosure may be considered broadly as a. part ofthe. work-support.

Rising, from. the right. end, of the work-support 2 is. a. ho1low. standard. 4. having formed; integrally Jonrnaled' in the. basev -l.',. beneath. the. worksupporting. plate 2,. is a rotary loop-taker driving shaft 9. which carries atfita forward end; a. looptaker. of. the rotary-hook lockrstitch type, designated generally as L. The. loop-taker comprises the usual. rotary hook. bobbin-case carrier element e journaled' thereihsbut. held against. re.- tati'on, bobbin-case c," nonsrotatalilyv mounted in the element e, and a bobbin-5. of'lower thread in the bobbin-case. As shown most clearly in Figs. 5 and. 6? the, bobbin-case carrier-element. is formed at. its needleeloop cast-off side. with a needle-loop controlling. .fi'ange; Hf. in the. upper portion of the. front. face of which isformed a rotation restrainingnotch [Lenteredi by a. tongue I2 of a rotation-restraining bar l3 mounted; on the underside of thework-support 2;.

The loop-taker driving shaft, BL is .iburnalediin bearings Hand [5" carried. by the base: [and is driven from themain shaft. T, .ata..ratfo of two-to-one, through the medium of a first pair of bevel gears l6, l7, ashaft I8 journaled lengthwise within the standard 4, and a second pair of bevel gears I9, 20. Thus the loop-taker is given two rotations for each rotation of the main shaft 1 At its forward end the shaft 1 has secured to it a crank-disk 2| carrying a crank-pin 22, which, through a link 23 and collar 24, transmits reciprocatory motions to an inclined'needle-bar 25 slidingly mounted in bearings 26 and 21 in the head 6. At its lower end, the needle-bar carries an eye-pointed needle N which, in the formation of stitches, cooperates with the looptaker L, before mentioned. The crank-pin 22 also actuates a link-type needle-thread take-up device, designated generally as 28, which cooperates with a manually regulatable needle-thread tension 29 in controlling the needle thread and in tightening and setting the stitch. Also mounted in the head 6, substantially parallel to the inclined needle-bar 25, is a spring-depressed presser-bar 30 which carries, at its lower end, a presser-foot 3 I.

The work is advanced past the stitch-forming mechanism by a four-motioned work-feeding mechanism including a feed-drive rock-shaft 32, and a feed-lift rock-shaft 33 each journaled in bearings depending from the work-plat 2. The feed-drive rock-shaft has upstanding arms 34, the upper ends of which are pivotally connected at 34*, to the rear end of feed-bar 35 carrying the serrated feed-dog 11. Preferably the arms 34, of the feed-drive rock-shaft, are so arranged that their pivotal connection with the feed-bar 35 is located rearwardly of and never intersects a vertical plane containing the axis of the shaft 32. Thus, during endwise movements of the feed-bar, the pivotal point 34 'is, at all times, either rising or falling. This produces the desirable effect of raising the rear end of the feed-dog in advance of the forward end thereof and causing the rear end of the feed-dog to drop quickly near the end of the feeding stroke.

At its forward end, the feed-bar carries a stud 3'! upon which is journaled a block 38 slidingly fitted within the forked free end of an arm 39 secured upon the feed-lift rock-shaft. By reason of this location and arrangement of the lifter fork and stud (which is the reverse of that commonly employed, the fork usually being formed as a part of the feed-bar and the stud usually being carried by an arm on the feed-lift shaft) greater clearance is afforded in the region of the loop-taker, thereby rendering it more convenient to withdraw the bobbin-case for the insertion and removal of bobbins.

The feed-drive rock-shaft 32 and the feed-lift rock-shaft 33 are actuated from eccentrics 40 and 4| carried by the main shaft 1 through the medium of pitmans 42 and 43 connected to rock arms 44 and 45 carried, respectively, by the shafts 32 and 33.

Secured to the under side of the base I is the casing 45 of an oil pump 0 which draws oil from a reservoir, formed in a pan on which the machine is normally supported, and forces the oil through suitable conduits to the various bearings throughout the machine. This pump is actuated by a vertically arranged shaft 41, journaled in the pump casing and driven from the bevel gear 20 by a mating bevel gear 48.

As hereinbefore stated, this invention has as an object to improve the sewing qualities of, high speed lock-stitch sewing machines. This" has been attained by a novel construction and arrangement of parts now to be described. Referring particularly to Figs. 3 and 6 it will be seen that, in accordance with the present invention, the shaft 9, and therefore the axis of rotation of the loop-taker, is arranged in a plane a substantially to one side of and parallel to a plane b. which latter plane isnormal to the work-supporting surface of the machine and passes through the needle-hole in the V throat-plate. This places the thread-guiding aperture 49, through which the bobbin thread t emerges from the bobbin-case 0', only slightly to the rear of the rear wall 50 of the needle-hole n. With this arrangement the bobbin thread extends more nearly vertically from the aperture 49 to the needle-hole than it does in prior machines. Therefore, during the feed of the work, the bobbin thread is not snubbed about the wall 50 to the extent or with the pressure that it is snubbed in prior machines. Because of this reduced snubbing action, and reduced pressure of the bobbinthread on the wall 59, the feed of the work is facilitated, thereby producing more uniform sewing and enabling the needle-thread loop to be more readily pulled up between the bobbin thread and the wall 50 during the tightening of the stitch. Likewise this reduction in pressure between the bobbin thread if and the wall 50 greatly reduces the sawing action between the needle and bobbin threads.-

To maintain the most desirable relation be tween the needle and the loop-taker, that is, with the needle reciprocating in a plane intersecting the axis of the loop-taker, the needle-bar has been tipped backwardly awa from the front edge I of the work-plate. This causes the needle to be reciprocated in a plane a (Fig. 6) diagonally through the work 10, needle-hole n and directly toward the axis of the loop-taker. Preferably, as-shown in Fig. 3, this inclination of the needlebar, and the needle carried thereby, is attained by tipping the entire bracket-arm rearwardly relative to the work-support, but obviously similar results may be obtained by merely tipping the bracket-arm head or by arranging the needlebar at an inclination in a conventional vertical bracket-arm head.

Inclination of the entire bracket-arm is particularly advantageous in that it affords better visibility at the stitching point, minimizes interference with the operator in handling the work and materially reduces the likelihood of having the operators head contact parts of the sewing machine, even when she is closely scrutinizing the work at the stitching point.

While the distance which the axis of the looptaker is offset from the plane b, passing through the center of the needle-hole, may vary, as may also the inclination of the plane 0 in which the needle reciprocates, it has been found that excellent results are obtained by offsetting the looptaker approximately 60 of an inch and inclining the plane of reciprocation of the needle about eleven degrees.

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

1. In a sewing machine having a work-support provided with a needle-aperture, in combination, an endwise reciprocatory needle operating through said needle-aperture, means for reciprocating said needle, work-feeding means, a looptaker disposed below said work-support for rotation about an axis transverse to the line of feed of the work, said axis being disposed in a plane spaced irf the line Offdi front a parallel: plane containing: said needle-apertures and. normal: to

said work-support; andia. bobbirr thread; carrier journaled: in and restrained against rotation with said loop-taker; saidi thread-carrier having. bob:- bin-thread delivery meansdisposedat': theneedlee aperture side of\ said; plane which contains the axisof rotation of saidloop taker;

2;. In a sewing machine having a. horizontally disposed work-support provided with. a needle:- aperture; in: combination,. an; endwise' reciprocatory needle operating through said; needle -aperture; means for reciprocating said needle, workfeeding means;. a loop-taken disposed belowsaid work-support for. rotation: about an" axis: transverse to the line of feed of the" work,.. said;' axis being disposedsin a vertical. plane at one side of a: parallel plane containing said: needle-aperture;

and a bobbin-thread carrier-jjournaledaim and; re.- strained against rotation with said loop-taker; saidzthread-carrier having. bobbinethread delivery means: disposed at that side: of. the thread-carrier toward: which the beak of the" loop-taker moves imits-loop-taking movement-..

3; In asew-ingmachine having; a horizontally disposed. work-support. provided with a; needleaperture,, in combination; an endwise recipro 'ca-tory needle operating in an inclined .plane through said. needle-aperture; means. for reciprocating said needle in said plane, work-feeding means, a loop-taker disposed below said worksupport for rotation: about a horizontal axis taker, said thread-carrier having bobbin-thread delivery means disposed at, that, side oi the threadecarrier toward. which the: beak of. the

loop-taker moves in its loop-taking. movement.

4. I n-Jasewing: machine: having; a. horizontally disposedweds-support provided with a needleaperture-,, in combination, an endwise: r.ecipro:--

eatery needle; operating;- in a downwardly and forwardlyinclined: plane: through said needleaperture,, means for reciprocating said. needle: in said. plane, work-feeding means; a loop-taker disposed below said work-support for rotation about an: axis transverse to the line: of feedsof the: work; said. axis being, disposed. in a: vertical plane forwardly of a parallel: plane containing said. needle-aperture, and a circular bobbinthread carrier journaled. in: and restrained against rotation with. said loop-taker; said thread-carrier having bobbinethreadz delivery 'means; disposed rearwardly of the last named plane-a distance substantially less; than the radius of said. thread-carrier,

5. In. a. sewing machine having: a; horizontally disposed work-support. provided; with; a needle: 1

aperture, in. combination, an end wise recipro catory needle operating; in an: inclined plane i through said needle-aperture; means fonrecip'irocating said needle in said plane;v a loop -taker disposedbelow said work-support forrotation about a horizontal axis, said; axis being, disposed in a vertical plane forwardly of a parallelv plane containing; said needle-aperture; work feeding means including a feeded-rive rock-shaft having an. upstanding arm, a feed-lift" rock-shafthaving rear end pivotally; connected tothe arm on! said feed-driver rock-shaft and its; forward? end. slid.- inglvconnected. with: the fork Orr-said: feed-lift i a laterally extending fork, a feed-bar having its rock-shaft: forwardly oi the forward. periphery;

ofi said loop-taken. a: feed-dog carried by saith feedeban, and? a2 bobbin-thread carrier journaled in andzrestraineda against; rotation with. said loop taker; said thread-carrier having, bobbins-thread delivery means disposed at that side of the thread-ecarrier toward. which: the: beak of' the loop-taker moves" in: its: loop-taking movement.

6: In a. sewing machine havinga. horizontally disposed; work-support provided with: a: needleaperture, in. combination, an endwise: reciprocatory' needle operating. in a; downwardly and forwardly inclinedz. plane. through said. needle-= aperture; means for.' reciprocatingsaid needle in said; plane;.a.loop-taker disposed below'said work.- support for: rotationabout' a horizontal axis; said axis; being: disposed in: a; vertical plane: forwardly: ofiv a parallel; plane containing; said needle-aper-- 1111116,,WOIkf86di11g' means including; a feed-drive rock-shaft journaled. adjacent; the rear. of said work-support and having an upstanding arm movable; only between: a vertical plane extend.- i-ng'. lengthwise of said( rock-shaft; and a. plane inclinedrearwardly therefrom, a feeds-lift rock.- sha'ft journaled: adj acent the front. of. said worksupport andahaving a. fork; extending rearwardly" toward. thev axis: of. rotationof. said loop -taker: but: terminating; forwardly of the periphery of the loop-taker;. a feed-bar having its rear: end piv-i ot'all y connected to? the: arm. of said, feededrive rockrshaft; andiits: forward end slidingly cone nected; with. said fork, a. feed-dog carried. by said feed-bar; and? a: circular bobbin-thread. carrier iournaled in and: restrained; against rotationwith said? loop-taker; said; thread-carrier having bob:- bim-thread: delivery" means disposed rearwardlp of thal'ast named. plane a distancesubstantially less than the radius: of said-v thread=-carrier..

' In a. lock-stitch: sewing machine. having.. a horizontally disposed work-support provided. with a needle-aperture. work-feeding mechanism;v a reciprocatory needle operating through said-needie-aperture; a. rotary: hook complementa'l to said surfacet'and'passing; through the center of. said mentalities including an: eye.- pointed needle and a rotary hook having: a loop-seizing: heal: travelili'ng: in. a vertical circular-path in av counterclockwise direction as viewed; from: theiopen. face: of the hook, and means foitreciprocating thesneedl'e 1 to causeitito: present: a. thread-loop to.- the book-'- beak; said. needle being so: disposed with. respect to said rotary hauls that; it presents: thetlirea'daloop to the hook beak, while said beak is travelling from its highest to its lowest vertical positions.

11. A lock-stitch sewing machine comprising a work-support provided with a needle-aperture, work-feeding mechanism, a reciprocatory needle operating through said needle-aperture, a rotary loop-taker complemental to said needle in the formation of lock-stitches, and means for rotating said loop-taker about an axis offset from a plane normal to the work-support and containing said needle aperture and which plane extends transverse to the line of feed.

12. A lock-stitch sewing machine comprising a work-support provided with a needle aperture, work-feeding mechanism, a reciprocating needle operating through said needle aperture in a plane inclined to a plane normal to said work-support and containing said needle aperture and transverse to the line of feed, and a rotary loop-taker located at the under side of said Work-support and cooperating with said needle in the formation of lock-stitches, said loop-taker having its axis of rotation located at that side of said plane normal to said work-support at which the point of the needle is located when in its lowermost position.

13. A sewing machine having sewing instrumentalities including an eye-pointed needle reciprocating in a fixed path, and a rotary hook having a loop-seizing beak travelling in a vertical circular path, and means for reciprocating the needle to cause it to present a thread-loop to the hook beak, said needle being so disposed with respect to said rotary hook that it presents the thread-loop to the hook-beak while said beak is travelling between its highest and lowest vertical positions.

14. In asewing machine having a work-support provided with a needle-aperture, in combination, a reciprocatory needle, a feed-dog operating through said work-support, a feed-advance rockarm disposed below said work-support, a feed-bar pivotally connected to said rock-arm and carrying said feed-dog, a feed-lift rock-arm having a fork directed toward said feed-advance rock-arm, operative connections between said fork and said feed-bar for imparting work engaging and releasing movements to said feed-dog, a rotary looptaker complemental to said needle in the formation of lock-stitches, said loop-taker having a thread-loop seizing beak rotatable in a plane normay to said work-support, a thread-carrier journaled in and restrained against rotation with said loop-taker, and a rotary loop-taker carrying shaft having its axis of rotation ofiset from a plane containing said needle-aperture, which plane is normal to said work-support and transverse to the line of feed.

15. In a sewing machine having a work-support provided with a needle-aperture, in combination, a reciprocatory needle, a feed-dog operating through said work-support, a feed-advance rockarm disposed below said work-support, a feed-bar pivotally connected to said rock-arm and carrying said feed-dog, a feed-lift rock-arm having a fork directed toward said feed-advance rock-arm, operative connections between said fork and said feed-bar for imparting work engaging and releasing movements to said feed-dog, a. rotary looptaker complemental to said needle in the formation of lock-stitches, said loop-taker having a thread-loop seizing beak rotatable in a plane normal to said work-support, a thread-carrier journaled in and restrained against rotation with said loop-taker, and a rotary loop-taker carrying shaft having its axis of rotation disposed at the feedlift rock-arm side of a plane containing said needle-aperture, which plane is normal to said work-support and transverse to the line of feed.

16. In a sewing machine having a bracket-arm head and a work-support provided with a needleaperture, in combination, a reciprocatory needle, a feed-dog operating through said work-support, a feed-advance rock-arm disposed below said work-support and having a path of movement wholly rearwardly of a plane normal to said worksupport and extending in the direction of the axis of oscillation of said rock-arm, a feed-bar pivotally connected to said rock-arm and carrying said feed-dog, a feed-lift rock-arm having a fork directed toward said feed-advance rock-arm, operative connections between said fork and said feedbar for imparting work engaging and releasing movements to said feed-dog, a spring-depressed presser-bar mounted in said bracket-arm head and upwardly inclined rearwardly, a presser-foot carried by said presser-bar and having a sole portion bearing flatwise on said work-support, a rotary loop-taker complemental to said needle in the formation of lock-stitches, said loop-taker having a thread-loop seizing beak rotatable in the plane normal to said work-support, a threadcarrier journaled in and restrained against rotation with said loop-taker, and a rotary loop-taker carrying shaft having its axis of rotation disposed at the feed-lift rock-arm side of a plane contain-' ing said needle-aperture, which plane is normal to said work-support and transverse to the line of feed.

ANDREW B. CLAYTON.

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