US2389124A

US2389124A - Thread controlling device for sewing machines

Info

Publication number: US2389124A
Application number: US529465A
Authority: US
Inventors: Ashworth Fred
Original assignee: United Shoe Machinery Corp
Current assignee: United Shoe Machinery Corp
Priority date: 1944-04-04
Filing date: 1944-04-04
Publication date: 1945-11-20
Anticipated expiration: 1962-11-20

Description

Nov, 20, 1945. F. A SHWORTH 2,389,124

THREAD CONTROLLING DEVICE FOR SEWING MACHINES Filed April 4, 1944 2 Sheets-Sheet 1 Eventor FRED ASf/h/OR 77/ Nov 20, 1945, wom- 2,389,124

THREAD CONTROLLING DEVICE FOR SEWING MACHINES Filed April 4, 1944 2 Sheets-Sheet 2 Patented Nov. 20, 1945 THREAD GONTROLLING: DEVICE EOE;

Fred Ashworth, Wenham; Mass;, assignor to. United". Shoe Machinery Qorporatiomflmihg ton; N. J'-., a corporation of'NewJersey AipplicatiomAprilA;1944,,SeriaLNmj29a465 10 Gianna.

The: present. invention. relates; to.- improvements.

in thread controlling devices for use. sew n machines: of the: type. intended. for operation: on shoes on other heavy materials and: provided: with a curved hook needle and a take-up acting: to take: up. each. loop of thread; drawn. throu h. the worle by the needle: and to give- 1111 hre d; durin each. sem'ng: cycle at: a. rate greater than; required by the; other stitch. forming. d'evicesrso that the portion: ofi thread: engaging: the. takeeupi becomes slack during a substantial part of each sewing cycie. An; example: of a machine: of this: type is disclosed in mated: States Letters Batent: No; 2271 6141; of. February 3; 19.42; 015 which: the presinventor: is ioint patentee andi, in certain recspects, the present invention is related to features disclosed in. invlentors. Unitedi States; Lettera FatenlzNo:.Z;35(l,995 of June 13;, 19431..

In the machineoi- PatentNo. 2;?37 1,611,.a thread tensioning: device acts on. the. thread. b'etweena' the take-up and the last formedi stitchthe. work to; keep; those. portions: of the thread engaging: the stitch; forming; devices, other.- than. the take-up; under control. while; the. take-up is giving; up thread to: said other stitch forming devices. In order.- to. avoid} thev effects of. excessive: friction and abrasion; on; the thread: while: the: taint-upis taking up: thread. anda particularly while 2i. stitch is; being set, mechanism. driver-r from the; main sewingshaft at the patented: machine is provided for. actuating. thetensioning. device: to: relieve the frictional effect on. the; thread in each. sewin cycle.- while. the: ta-keeup. is? taking. up: thread; In the. machine of. Patent. No.. 2,350,995; the; change in tension oi; the. thread. is controlled directlsrby the thread. itself. without, theuse of-v any posietively driven actuating, mechanism separate from the; tensioning; device. The. tensioning device; of Batenh 2350 9.95 consists of. a. spring-pressed plate. and astationary' surface between which the threadiia compressed, the arrangement beinasil h that the transverse. movement. of. the thread. as a result 0t the action: of. the; take.-up,. causes the thread to move.- along; the plate from. a; position where; the: frictional. tension produced by spring pressure is; greater (hiring. the: giving-up: stroke oi the take-uptoapositionlwhere the pressureis substantially less; during? thatak'e-upu stroke of the take-up; This: arrangement. is? advantageous in that, it, provides efi'ecti'va control. of the: slack thread during. high: speeds: of operation; but. in order to; provide; accurate. control" of the thread under: all: conditions: of operatiom it: is desirable tm relieve the tension: entirely on the thread dur atportionz of: the" giving-up: stroke: of the takeup; as: Well as; during: the taking-up stroke while during the; remainder-01f I the: giving-up stroke; the usuali amount on tension. impartedlhy the spring:- pressed; plate'is needed;

In the operation. of." aihook needle sewing: ma.- chine: after the: needle the work. from. one side andz'emerg'es tromithe other-side, a:v loop. of threadislaid inthe needlehookzbya loopenthe thread having. previousi'y, been enga ed; with. a thread finger-'andmeasuredcfi; from the supply sufficiently in. amount tdprovide slack thread; hes tween;therpreviously'lormedstitclt andthe needle at least until. the needle .hnoichas. been withdrawn with the; thread; a. substantial; distance from; the side: of. the: Work. at; which it entered If insufiilcienir. slack: thread; provided between the; last formedi stitch anm the needle to; enable the threaded needle hook. to: pass: through. and: be withdrawn. 2; substantiak distance fr m the Work, the threadgbetween the; needle; and th r t t may be; pulled ton tightly the needle hookis being; drawn throughthe: work, at which time, a maximum. amount at abrasion. on; the thread: occurs, the; thread of: the-loop.= carriedby the; needle being compressed in the form. of:a.sharp:=bightin theneedle hook. Under these: conditions a. number:- of. d'rfiiculties; arise; The: abrasion ofithe thread. atthez hight engaging the needle hook may he so: excessive. as; to: strand the. thread, the previnusiy formed: stitch may be. displaced by'stealing' thread; therefrom; or the thread may become stretched excessively or broken,

Mter the threaded needle hasbeen withdrawn fully fromcthe work, the machineisof thelockstitchl type, some form of thread lifter or loop spreader and a. loop taker are employed which enter the loop carried by'the' needle hook; drawing; thread from: the: supply as the needle continuestowithd'raw from the work; S'omesliding movement onreeving of the thread through the needle hook iaunavoidable at'this time, but the thread noil'e'nger has a sharpbightf-ormation in the: needle;. so that there is lesslikelihood of injury tozthe threadl During this action, the thread is. being: dragged through the needle perforation im the. Worhwhich: itself: causessome tension in the thread. so that control of thethread onthe needlesideof theaworkis assured. If'at this time further: frictional-I drag is imparted by" the tensibnihg: device, the drag: on the thread while sliding through the needle hook under some circumstances may be excessive If no drag atall is imparted to the: thread beneath the work at the take-un side; there: may be:- other' undesirable resultsttolbezexplained;

During the transfer of the needle loop from the thread lifter and needle to the loop taker, the speed of movement of the thread, as it is being withdrawn from the work, changes abruptly, being withdrawn at first rapidly by the thread lifter and then more slowly as the loop is entered by the loop taker. If the thread between th take-up and the work is substantially free of tension at this time, the momentum of the thread under movement of the thread lifter will carry the thread beneath the work out of its straightline path between the take-up and the work,

causing it to twist and slap against adjacent parts tends to apply periods of momentary erratic resistance to the movement of the thread,'contributing to non-uniformity in movements of the thread while being disengaged from the thread lifter and engaged by the loop taker. -Non-uniformity in movements of the thread during for-. mation of a stitch at this time is reflected in irregularly formed stitches and varying tensions in the threads of completed stitches.

One object of the present invention is to provide a curved h'ook needle sewing machine of the type referred to which will insert an extremely uniform seam with little or no abrasion to the thread and in which the difficulties above enumerated are overcome. Another object is to simplify and improve the construction and mode of operation of a lockstitch shoe sewing machine, particularly with respect to regularity of stitch formation and location of stitches in the work operated upon. Another object of the invention is to provide a frictional thread tensioning device between the take-up and the work for a lockstitch sh'oe sewing machine which will operate in a desirable manner and will prevent erratic movements in the thread during the iving-up strokeof the take-up as a result of changes in velocity. of thread movement, particularly while each needle loop isbeing transferred from the needle to the loop taker.

In the illustrated embodiment of the invention, a hook needle sewing machine, having a needle loo-per for laying, the .thread in the needle hook and a take-up, is equipped with means acting on the needle thread between the take-up and the looper to cause tension to be imparted to the thread while the thread is being laid in the needle hook and, thereafter, to relieve the tension on the thread, at least until the hook of the needle has drawn the bight in the thread loop' carried thereby into the work. Preferably, the tension imparting means consists of a device actuated during each sewing cycle by suitable positively driven mechanism rather than depending wholly upon the movements of the thread while being acted upon by the take-up, and in the illustrated form of this feature the tensioning device is actuated to relieve the tension until the needle has withdrawn its loop from the work. At the time of withdrawal, while the needle still engages the thread, the loop is first entered by the thread lifter, the lifter in the form of the invention hereinafter described havingsubstantially reached the extreme end of its. spreading movement before the tension is reapplied. In order to prevent irregular movements of the thread while the needle loop is being transferred from the thread lifter to the loop taker, the tension is again applied to the thread by the tensioning device just before the loop escapes from'the needle and lifter, thus preventing the thread between the take-up and the looper from becoming loose as a result of its inertia and slapping against the adjacent machine parts or portions of the work.

These and other features of the invention consist of the novel constructions, combinations and arrangements of parts, as will become more fully apparent from the following detailed specification taken in connectionwith the accompanying drawings, in which Fig. l is a view in left-hand side elevation of so much of a curved hook needle lockstitch shoe sewing machine as is necessary for an illustration of an embodiment of the present invention, the parts of the machine being indicated in positions assumed while the needle is being looped;

Fig. 2 is a similer view of the same portions of the machine illustrated in Fig. l with the parts in positions assumed after the needle has been withdrawn from the work with its loop of thread and the loop is beingretracted toward stitch setting position;

Fig- 3 is a detail view on an enlarged scale of a tension releasing member illustrated in Figs. 1 and 2;

Fig. 4 is another detail view on a similar scale of the tension releasing member illustrated in Fig. 3, together with a connecting rod for actuating the tensioning device, the parts being viewed at right angles to the direction in which Fig. 3 is taken;

Fi 5 is a sectional view on an enlarged scale taken along the line VV of Fig. 1;

Fig. 6 is a detail view of a yielding tensioning plate forming the movable part of the tensioning device;

Fig. 7 is a detail view on a slightly enlarged scale of some of the parts of the machine illustrated in Fig. l in positions assumed at the time in each sewing cycle when the frictional tension 'on the thread is relieved;

Fig. 8 is a similar view of the parts in positions assumed while a needle loop is being transferred from the loop spreader to the loop taker; v

Fig. 9 is a view on a still further enlarged scale of a portion of the housing for the take-up, indicating the cover for the housing in closed position and the tensioning device operative, and

Fig. 10 is a plan view of the take-up housing and tensioning device illustrated in Fig. 9.

The machine illustrated in the drawings is a lockstitch shoe outsole sewing machine having a curved hook needle 2, a continuously rotating take-up 4, a looper 6, a thread finger 8, a loop taker or shuttle l0 enclosing a thread case ll having a supply of locking thread, a thread lifter or loop spreader [2 for opening each needle loop for the shuttle, and other stitch forming devices similar in construction and mode of operation except as hereinafter pointed out to those disclosed in Patent Nos. 2,271,611 and 2,350,995 above referred to. As in the machine of thepatents, the stitch forming devices are so operated that substantially no tension will be imparted to the needle thread l3 by the take-up in each sewing cycle except when each stitch is being set. To control the needle'thread while each loop is being formed and carried about the thread case in the machine of the patents, a frictional thread tensioning device is provided between the take-up and the work so that sufficient'tension will be applied to the thread between the time the needle is looped and drawn throughthe work and the time the needle loopreaches a position of maximum extension about the thread case, the tensioning device assisting theneedlelooping' oper ation and preventing displacement at the thread fromthe hookof the needl'e asthe threaded needle movesupwardly'through the work; The ten sioning' device of Patent- No. 2350,9953 is mounted directly upon astationary circularlyflanged shield comprising a housing for the take-up, a corresponding flanged shield being indicated at I 4 in thepresent illustrated machine Cooperating with the shield: I4 to prevent escape of the needle thread: from control. of the take-up is a cover: plate L6? hingedly mounted onipins l3=- on the take-uphousing;

The take-up 4 consistsof. an arm rotating con tinuou'sly in the. direction ot the arrow between the cover and thezshield with.atake-up shaitZO passing throughsthe shield. and? carrying. thetakeup arm at one end. The rotation of-v the-shaft 20 is: timed with. the. operation of. the. other stitch forming; devices to. causethe threadiengaging. the take-up.- to. be: given. upv as; the looper 6 lays the thread in the. hook of the. needle. The. needle draws the thread into a loop while. moving up.- wardly. through the work, thetwosides of the loop forming. a, sharp. bight engaging. the. needle. While the thread bight of. theneedle loop isibeing carried through the. workwith the needle hook, itis subject. to substantial compression. against the. inner surfaces of. the needle perforation and to frictional abrasion. The compression: of: the thread in the bight carried by the needle varies with; the type of work operated upon and,.in.some

instances,v may produce excessive. friction. and

abrasion and injury to the thread.v

To avoid unnecessary injury to the: thread in many sewing machines of the hook needle. type, a predetermined length is: measured. between the thread finger and the last. formed stitch. in the work, as illustrated in Fig, 1, before the looper lays the thread in the needle hook. The length of thread thus measured is intended to enable passage of the needle loop through the work without requiring sliding movement. of the thread through the needle hook. In many machines heretofore used commercially, the threadis kept under controlby actuating, the take-up to give up thread. only in the. amount required, noslack. be.- ingpermitted. The take-up 4: of. the machine disclosed in the patents is actuated to" provide slack threadby giving upmore thread than is required for the needle looping. operation. and the tensioningdevice on the take-up housing im-' parts only a lightfrictional. drag on. the thread tokeep the thread between the tensioning device and. the work. under just enough tension to insure laying. the thread securely withinthe needle hook. ssoon as the thread is laid in the needle hook, however, the thread finger moves to give up its supply of measured thread and, inv so do ing, reduces the tension in that part of the thread between the needle hook and the. last formed stitch. Tension in the thread between the needle hookand the tensioning device. atthis time may cause the thread to slidein the needle hook before the. threaded hook enters. the work since the thread tends. to move. in the direction of greatest tension. The. result ofsuch sliding movement is to cause at least partial loss of thread: measured. by the. thread finger so that the thread. between the needle and. the last formed stitch may be. subject to the same excessive tension and abrasion beforethe threaded needle hook is withdrawnv from the opposite side. of. the work, as though no measurement-had. occurred. Ifthe thread is exceptionally strong, satisfactory stitches: may still be formed even. under these conditions, particularly where: excessively large size of needle hook: is; employed. orthe: ma.- chine is operated at. slowspeeds: Witha. small.- sized needle: hook as: compared to. the size; of thread utilized, itis; necessary to compress; the thread tightly intdthe. hoolnirr order to prevent a few strands from escaping and, with relatively poor: walityfthread any tendency: to; slide in the needleshook; before; the threaded needle is. with.- drawn from the worlqsubiectszthethreadzto C61?- taimihjury. or breakagez.

Toiovercomathesedifficulties, while ati-thezsame enabling easy'passage: of the needlev thread through the work without. liability of: injury or excessive abrasion". on. the: thread inth'e. machine embodying the; teat-ureszoi the present invention, the take-up housing: has; mounted on. it av triotionalrtensioniherdeviceactuatedlahsuitableztimes bathrby transverse movement of the: thread and by separate mechanism to. change; the. tension in the. threadin a desiredimanner; The tensioning device. comprises; a. vertical plate 22: backed atits forward; endby; a. pair. of spring-pressed. plungers Pal: slidingly. mountedin horizontalpassagesin the take-uphousing. At.it's rearward end, the plate has;:a horizontal: slotted tab slidingly mounted in a: cut: formed in. a. block: 26 securedv to. they housingl. Td-hoId the tab loosely in position, theblock has a vertical passage into which isdriven a repiILZB; entering the: slot. in the tab. At its forward end,. the: tensioning plate has. an open slot. to: receive a horizontal: positioning pin 29 secured; in: the; takeZ-up. housing.

mtheitensioningrdevice oi-Patent No. 2,350,995, theztensioningplateis.drawnagainst a horizontal surface of a. blUCkE on. the. housing for the takeupr;.requiringithe'threadito be introduced between the plate anldablocls while threading'themachine. In: the present-J illustrated machine, the necessity ofintroducing the-thread between the tensioning plate and the; supporting. block is avoided, the tensinning. plate being: pressedv by the plungers 24 againstahorizontalihiction surface on a block 38 secured. by means or screws: 32 to the take-up cover: plate; 162. The: arrangement is: such that, with; the thread. located. in. operating position" on the take-up while the cover plate. It is open during: threading: of the. machine, proper location or the thread. witlt respect to the tensioning plate iginsnred' when; the. take-up cover plate is'closed.

The: operatiomof thetensioning plate 22 in imparting", tension to. thethread is. substantially the same as that; in. Patent No.. 2,350,995 in which there lSi a. very light frictional pressure on the thread whilezt'he. takei-uplis takingup-thread from the otherstitch formingrdevices', as in Fig. 2, thus avoiding unnecessary abrasion on the thread.

While the take-up isstaking: up: thread, the-thread is; drawn. against: a. flanged. guide wheel 34' rotatable on a screw 36 threaded. into the block 26. When the take-up reaches the lower end of its takingrup stroke after. the stitch being formed is set. in the work, the. thread between the take-up andat'he l'ooper: movesv transversely oi its length away' from the guide wheel 34: and, thereafter, the: stitch setting: tension. on the thread is sub- 1 stantially' relieved; Asisoonas the take-up begins its; giving-up strokathe. thread is engaged with the thread finger 8 (Fig. 1i) and is laid in the hook of. the-needle by'tha l'ooper 6, the take-up providing;- slacl'c thread. during these operations. In: moving: away, from the guide wheel 34, the thread is carried forwardly toward the portion of I the tensioning; plate acted upon by the plungers 24. While engaged by that portion of the tension plate acted upon by the plungers 24, a substantial amount of frictional tension is imparted to the thread. In addition to operation of the tensioning device by transverse movement of the thread, it is also actuated by suitable mechanism to prevent loss in thread measured by the thread finger.

The mechanism for actuating the tensioning device apart from the transverse movements of the thread includes a swinging tension release member 31 pivotally mounted at 38 in a lug 40 located within a radial depression 42 formed in 'the Shield [4. The lug 40 is located near the takeup shaft on the shield, and the release member is bifurcated to embrace the lug at one end. At its other end, the release member is provided with an arcuate extension having a cam surface 44 disposed within the rotary path of the takeup to be actuated thereby. Between the release member and the shield, there is a compression spring 46 for pressing the release member into the path of the take-up. The cam surface 44 is so shaped that, during the giving-up stroke of the take-up, the release member will be swung about its pivot 38 at a time in the sewing cycle directly after the thread is laid in the hook of the needle 2 and before substantial forward thread releasing movement of the thread finger occurs '(see Fig. 7)

The connections between the release member .31 and the tension plate comprise an upwardly extending arm on the release member having its upper extremity fitting within a slot in a horizontal connecting rod 48 slidingly mounted in a suitable guideway in the take-up housing beyond the range of the take-up path. Diametrically opposite to the release member receiving slot in the connecting rod 48 and at its other end, is a second slot into which is loosely engaged an extension of the tensioning plate 22, the parts being so arranged that, when the release member is engaged by the take-up, the tensioning plate is moved away from the thread engaging surface of the block 30, thereby relieving the compression on the thread. The tension on the thread between the tensioning device and the work is held relieved in this way until after the threaded needle has fully been withdrawn from the work and the thread lifter I2 has not only entered and spread the needle loop but has approached the extreme end of its loop spreading movement. At this time, the shuttle is beginning to enter the loop spread by the thread lifter, as best, shown in Fig. 8. As the thread lifter approaches the extreme upper end of its loop spreading movement, its rate of travel is retarded so that, unless tension is immediately applied to the thread between the takeup and the work, there will be an opportunity for the thread to whip and become displaced, twisting itself around adjacent parts, particularly the looper, or slapping against the upper of a shoe being operated upon, in an irregular manner indicated by the dot-dash lines. When the machine is operating at high speeds, such irregular movements of the thread impart momentary tension and resist uniform movements of the thread in the needle loop from one sewing cycle to another, tending to cause breakage or imperfect stitch formation. As soon as the shuttle enters a needle loop, the thread is disengaged, first from the needle and then from the thread lifter, and is carried about the thread case in the usual way.

At all other times in each sewing cycle, the

tension device is effective to maintain the thread between the take-up and the work under control in the same manner as that disclosed in inventors Patent No. 2,350,995, the temporary relief of tension on the thread occurring only between the times the needle is looped and the approach of the thread lifter to the extreme end of its loop spreading movement before the loop has been disengaged from the needle and thread lifter. Relief of the tension on the needle thread in this way not only is advantageous in preventing non-uniform sliding movements in the hook of the needle and elsewhere and consequent abrasion of the thread while each needle loop is being drawn through the work but also assists in a uniform location of the spread loop for the shuttle and a subsequent uniform loop spreading action of the shuttle in opening up the loop for its passage about the thread case during each sewing cycle. Uniform movements of the loop during the formation or" each stitch are conducive to uniform location and setting of stitches in the work. A secondary advantage, resulting from the actuation of the tensioning device directly from the take-up, rather than from mechanism actuated by the main sewing shaft as in the machine of Patent No. 2,271,611, follows from the use of a relatively simple mechanism for relieving the tension positively in addition to its variation as the result of transverse thread movement.

The nature and scope of the invention having been indicated and a particular embodiment thereof having been specifically described, what is claimed is:

1. A sewing machine having a hook needle, a looper for laying the thread in the needle hook and a take-up, in combination with means acting on the needle thread between the take-up and thelooper tocause tension to be imparted to the thread while the thread is being laid in the needle hook and to relieve the tension on the thread after the thread is laid in the needle hook until the hook of the needle has drawn the thread into the work.

2. A sewing machine having a hook needle, a looper for laying a loop of thread in the needle hook, a thread finger for measuring thread between the needle and the last-formed stitch in the work and for giving up the measured thread after the thread is laid in the needle hook, a takeup, mechanism for actuating the take-up to provide slack in the needle thread as the needle hook carries each needle loop through the work and to set each stitch, and a tensioning device acting on the thread between the take-up and the looper, in combination with mechanism for actuating the tensioning device during each sewing cycle to relieve the tension on the thread after being laid in the needle hook and until the hook of the needle has drawn the needle loop into the work.

3. A sewing machine having a hook needle, a looper for laying a loop of thread in the needle hook, a thread finger for measuring thread between the needle and the last-formed stitch in the work and for giving up the measured thread after the thread is laid in the needle hook, a takeup, mechanism for actuating the take-up to provide slack in the needle thread as the needle hook carries each needle loop through the work and to set each stitch, and a tensioning device acting on the thread between the take-up and the looper, in combination with mechanism for actuating the tensioning device during each sewing cycle to relieve the tension on the thread before the hook of the needle draws the needle loop into the work and until the needle has withdrawn the loop from the work.

4. A lockstitch sewing machine having stitch forming devices including a hook needle, a looper, a locking thread case, a rotary loop taker for passing loops of needle thread over the'thread case, a thread lifter for spreading each needle loop for the loop taker, a continuously rotating take-up arranged to provide slack in the needle thread as each needle loop is being drawn through the work by stitch forming devices other than the take-up and to pull each needle loop from the loop taker, and a frictional tensioning device acting with a yielding pressure on the thread between the looper and the take-up, in combination with mechanism for actuating the tensioning device during each sewing cycle to relieve the tension on the thread before the hook of the needle draws the thread into the work and until the thread lifter approaches the extreme end of its loop spreading movement.

5. A lockstitch sewing machine having stitch forming devices including a hook needle, a looper, a locking thread case, a rotary loop taker for passing loops of needle thread over the thread case, a continuously rotating take-up arranged to provide slack in the needle thread as each needle loop is being drawn through the work by stitch forming devices other than the take-up and to pull each needle loop from the loop taker, and a frictional tensioning device acting with a yielding pressure on the thread between the looper and the take-up and comprising members having opposed thread engaging surfaces, in combination with a tension release member actuated by the take-up, and a connection between the tension release member and one of the tensioning members acting to separate the members while the needle is being looped and before the hook of the threaded needle enters the work.

6. A lockstitch sewing machine having stitch forming devices including a hook needle, a looper, a locking thread case, a rotary loop taker for passing loops of needle thread over the thread case, a continuously rotating take-up arranged to provide slack in the needle thread as each needle loop is being drawn through the work by stitch forming devices other than the take-up and to pull each needle loop from the loop taker, and a frictional tensioning device located outside the rotary path of the take-up to act on the thread between the looper and the take-up, in combination with a tension release member located within the rotary path of the take-up to be actuated thereby, and a connecting rod between the tension release member and the tensioning device.

'7. A sewing machine having stitch forming devices including a hook needle, a take-up acting to take up and give up thread and to move the thread transversely of its length, and a frictional tensioning device constructed and arranged to impart a variable tension to the thread the variation of which is controlled by transverse movement of the thread between the take-up and the work, in combination with mechanism for actuating the tensioning device to relieve the tension on the thread during each sewing cycle beIore the hook of the needle has drawn the thread into the work.

8. A sewing machine having stitch forming devices including a hook needle and a take-up, a shield for the take-up, and a hinged cover to enclose the take-up in the shield, in combination with a frictional tensioning device acting on the thread and comprising members having thread engaging surfaces, one of which is carried by the cover and one of which is actuated by the takeup toward and from the other member.

9. A sewing machine having stitch forming devices including a hook needle, a looper for laying a loop of thread in the needle hook, a continuously rotating take-up arranged to provide slack in the needle thread as each needle loop is being drawn through the work by stitch forming devices other than the take-up and to pull each needle loop into the work, a shield for the take-up, and a hinged cover plate to enclose the take-up in the shield, in combination with a frictional tensioning device acting on the thread and comprising members having thread engaging surfaces, one of which is carried by the cover plate and the other of which is mounted on the shield for relative movement toward and from the tensioning member on the cover plate while the cover plate is closed, and mechanism actuated by the take-up to separate the tensioning members between the times in each sewing cycle when the thread is laid in'the hook of the needle by the looper and when the needle draws the thread into the work.

10. A sewing machine having stitch forming devices including a, hook needle, a looper for laying a loop of thread in the needle hook, a continuously rotatin take-up arranged to provide slack in the needle thread as each needle loop is being drawn through the work by stitch forming devices other than the take-up and to pull each needle loop into the work, a shield for the take-up, and a hinged cover plate to enclose the take-up in the shield, in combination with a frictional tensioning device acting on the thread and comprising members having thread engaging surfaces, oneof which is carried by the cover plate and the other of which is mounted on the shield for relative movement toward and from the tensioning member on the cover plate while the cover plate is closed, a tension release member mounted on the shield within the rotary path of the take-up to be actuated thereby, and a connecting rod between the tension release member and the tensioning plate slidingly mounted on the shield for separating the tensioning members when the take-up engages the tension release member.

FRED ASHWOR'I'I-I.