US2321040A - Self-threading shuttle - Google Patents

Description

`lune 8, 1943. J B,v PLEVYAK v 2,321,040

- SELF THREADING SHUTTLE l Filed June 26, 1941 2 Sheets-Sheet l mmmlmlllIHIIINIIIIIIIIIIIIIIII(lill Z' n lllll n WIMmm /ea y June' 8, 1943. J, Bj PLEVYAK I 2,321,040 SELF THREADING SHUTTLE Filed June 2e, 1941 2 sheets-sheet 2 Y' f gm@ Jggvllev L MMM/mmf Patented June 8, 1,943

UNITED STATES PATENT FFICE SELF-THREADING SHUTTLE Joseph B. Plevyak, Newton, N. J.

Application June 26, 1941, Serial No. 399,881

10 Claims.

My invention relates to weavers shuttles, and more particularly to means for automatically rethreading the shuttle tensioning device when a new bobbin is placed in the shuttle.

The main object in View is to provide a device of this character so constructed that when a new bobbin is inserted in the shuttle for thread replenishment, the drag on the thread at the rst pick of the shuttle thereafter, will automatically elfect the proper placing of the thread in the tensioning devices, so that the weaving proceeds without interruption.

A minor object is to provide means for utilizing the drag upon the trailing end of the thread during said i'lrst ight, to elect the above automatic operation.

A third object subsidiary to said minor object just mentioned, is to provide a preliminary tensioning device located between the bobbin and the regu-lar tensioning device, whereby to oier suiiicient resistance to said drag on the free end of the trailing thread during the first pick of the shuttle after replenishment, to reliably effect said tension-threading operation.

' A further very important object is to automatically relievethe thread from said preliminary tensioning thereon, when the regular tensioning device has become threaded.

A still further object is to obtain the above results, by means of a simple and cheap construction having few parts easily manipulated, not liable to get out of order, and easily replaced whenworn out.

lQther objects will be noted in the subjeined description.

A leading feature of the invention consists of a pair 'of adjustable pressure plates located in the throat Yof the thread-slot, between which plates'the thread is passed immediately after leaving the bobbin, and before it reaches the regular tensioning devices, 'which devices have associated therewith a shelving portion composed o f ra series of ugers spaced slightly below the main thread slot of the shuttle, and projecting over the recess of the shuttle in which the regular tensioning devices are housed, said shelving lingers being arranged to cooperate with the tensioning devices to automatically direct the thread into operative relation with said devices upon the rst pick of the shuttle after thread replenishment,V

,The invention consists in certain novel features of. Aconstruction andrelative arrangement of parts-,11; as will "be, hereinafterv described and ing drawings, in which- Fig. 1 is a broken view of a top plan of a shuttle provided with my improvements, aportion of the top of the shuttle being removed to disclose the tensioning devices.

Fig. 2 is a similar top plan view with the cover in place on the shuttle; whereby toclearly show the main thread slot of the shuttle, and the preliminary tensioningldevice.

Fig. 3 is a cross-sectional view of the shuttle, showing in particular, an end view of the preliminary tensioning device.

Fig. 4 is a broken longitudinal section of the shuttle, showing a side view of said device'.

Fig. 5 is a broken longitudinal section o1' a shuttle showing aside elevationrof the regular tensioning devices'therein.

Fig. 6 is a fragmentary View on an enlarged scale, showing the relative position of the parts of the tensioning device when the shuttle is inl operation. f

Fig. 7 is a similar view showing the relative position of said parts of the tensioning device after the shuttle has startedr on its rst flight after thread replenishment.

Fig. 8 is a perspective view on an enlarged scale, of the tensioning arm.

Fig. 9 is a perspective, onta somewhat enlarged scale, rof the larger one of the two pressure plates which form the principal part of the preliminary tensioning device.

Fig. 10 shows inside elevation, the relative positionfof the preliminary tensioning Vdevice and the bobbin to each other.

Fig. 11 shows a top plan view of the preliminarytensioning device provided with means, controlled by the tension arm,'for timing the releasing action of the preliminary tensioning device to correspond to the relative position of the tension arm.

Fig; l2'is a slightly modified form of the same.

Fig. 13is an elevation/on an enlarged scale of the outerside; of the larger `one of the vpressure plates with the releasin'g'leverfcarried thereby as claimed, reference being had to the accompany;

shown in Fig. 12; and,`

Fig. V14 is a perspective, lo'nan ,enlarged scale", of the same with the releasing1ever'1eft'-orr-L Referring further to the drawings, the numeral l indicates the shuttle, andZ the removablelportion of the cover thereof, which is secured on the shuttle by a screw 3. The bobbin is indicated by 4, the thread or yarn by and the main threadslot in the top of the' shuttle by 6". Y

' The removablecover 2 of the shuttle is recessed on its under side, as indicated in dotted lines in Fig. 2.

Special attention is now called to one of the leading features of the invention, namely; the preliminary tensioning device located in the throat of the shuttle, which, after a new bobbin has been introduced into the shuttle, grips the thread thereby causing additional resistance to its passage from the bobbin to the regular tensioning device; and during the rst ypick of the shuttle thereafter, utilizes the increased dragtension thus imposed upon the thread, to operate the regular tensioning devices, and to direct the thread thereinto, and at that point, releases its grip on the thread and permits the regular tensioning devices to automatically move into relative tensioning relation to each other and to the thread, thereby leaving the preliminary tensioning device idle, and the regular tensioning devices in full control of the delivery of thread from the bobbineto the work, till such time as another bobbin is to be introduced into the shuttle; vhereupon the above operation is repeated.

TheV preliminary tensioning device thus referred to, consists of two plates and 8, the respective upper portions of which are yieldingly pressed into flat engagement with each other, to engage the thread which is passed between them preliminary to threading the regular tensioning devices of the shuttle`- These plates are preferably pressed into engagement with each other by means of a coil spring Il which is mounted in the side of the shuttle on the reduced inner end of a screw I0, as illustrated in Fig. l; so that by a turn of the screw in onedirection, or the other, the grip ofthe plates on the thread inserted between them is increased or diminished as may be desired. The plate I is slightly longer at its exit end than its mating plate 8, and this extended end is provided upwardly of its middle portion with a slight projecting portion I! bent somewhat inwardly in the direction of the other plate. It will be noticed that the corners of this inwardly-turned projection are eased off or rounded, as indicated at I Ia and IIb (see Figure 9). .The special purpose of this projectionwith its rounded corners will be pointed out later The slightly shorter member 8 of the mating plates has an oiT-set portiona, at its lower side (see Fig. 3), so that that portion cannot at any time come into flat engagement with ythe plate `I. These mating plates 'I and 8 are provided near their lower edges with small bores I2 which are adapted to be loosely received upon pins I3 anchored in the shuttle on opposite sides of the thread slot near the bottom thereof (see Fig. 3). As shown in Figs. l and 2, these mating plates are located at the entrance end of the rthread The huttle is provided with. arecess I4 in whichthe main tensioning devices are located. The side 14a of this recess farthest from the tensioning bar is inclinedl outwardly Vat an angle to the main threadslot of the shuttle, and eX- tends forwardly in the shuttle, and nally terminates in the usual thread-outlet opening I5 in the side of the shuttle near its forward end (see Fig. l).

The portion oi this recess immediately under the main thread slot 6 of the shuttle is provided with an overhanging shelf portion extending toward the Wall Ilia of the recess I4, but terminating a distance spaced therefrom about the width of the main thread slot 6 of the shuttle. The upper ends of the regular tensioning posts I6 are anchored in this shelving portion near the forward edge of the same and in alinement with the wall I4a of the recess I4, while the lower ends of these posts are anchored in the shuttle at the bottom of the recess, as illustrated in Fig. 5.

The tensioning bar Il works on a pivot I8 suitably anchored in the shuttle, and is provided with thread hooks I9 extending forwardly-andupwardly from the main bar I'I, as more clearly shown in Fig. 8. This bar also has a short integral arrn 23, extending outwardly from its pivot point I8; and attached to the upper end of thisv arm is a rubber band 2| arranged to pull in a direction to operate the tensioning arm with its hooks I9. The outer end of this elastic band is secured to a screw 22 by means of an opening 23 in the screw, whereby when the screw is rotated, the tension on the band may be regulated.

The upper ends of the tensioning hooks I9 extend slightly above the plane of the overhanging shelf portion which is generally indicated by the numeral 24, and this overhanging portion is provided with runways 25 which permit the upwardly extending tension hooks I9 to move to their normal tensioning position, as indicated in Figs. 1 and 6 of the drawings. The forming of the runways 25 in the overhanging shelf portion 24 forms the part of said portion immediately underneath said thread slot 6 into what for convenience and brevity may be termed the ngers of the tensioning device, which fingers are indicated by 24a.

When a new bobbin has been placed in the shuttle for thread replenishment, and the shuttle is picked, the drag on the thread rst draws the thread between the two plates 'I and 8 of the preliminary tensioning device at the upper meeting edges of said plates. It will be seen from Fig. 1 of the drawings that the spring 9 which presses said plates together, is located near the exit end of the device, so that the insertion of.

side of the upturned hooks I9 of the tensionarm,

which hooks project upwardly through the runways I4 to a point above the plane of the shelving portion, as shown in Fig. 5. The end of the thread extends on out through the side delivery eye of the shuttle. The pull on the portion of thread extending from the upper side of the projection IIa of the preliminary tensioning device to the side-delivery eye of the shuttle (see Figs. 1 and 9), tends to straighten thisk portion of the thread, and in doing so, to slip it laterally outward over the shelving ngers 24a into the recess I4; but the upturned thread hooksy I9 of the tensioning arm project upwardly through the runways 25 above the plane of the shelving portion as shown in Fig. 5, so that the thread in its effort to slip over the ends of the fingers 24a engages the projecting upper ends of the. tension.

hooks I9 and forces them outwardly beyond the ends of said fingers into engagement with the wall I4a of the recess I4, as illustrated in Fig. 7 of the drawings, in which it is shown that the thread now extends in a straight line from the projection I I of the preliminary tensioning device to the side delivery eye where it leaves the shuttle. The movement of the tension arm to this position is eifected against the tension of the short elastic cord 2|. The grip of the two plates 'I and 8 on the thread oi'ers sufficient resistance to the movement of the thread to impart very considerable tension thereto; and the greater this tension on the thread, the greater is its inclination to straighten itself, by which latter act it moves the tension against the pull of the elastic band 2I to the position shown in Fig. 7. From this figure it will also be noticed that the drag-pull on the thread causes it to Contact the thread-hook ISa at the outer end of the tension bar before it contacts the other thread hooks I9. This causes the force applied by the thread to the tension bar II, to operate upon the same with .maximum eiiciency because the hook I'Sa. is the hook farthest removed from the fulcrum I8 upon which the lever rocks. That the pull of the thread is greatest on the thread hook I9a at the outer end of the tension bar becomes more apparent when it is noted that at this point in the operation oi the device the thread is in the position illustrated by the line -5 in Fig. 9 of the drawings. Special attention is called to the fact that at this point in the operation of the device, the thread is still pressed between the pressure plates 'I and 8 near their upper meeting edges with a marked downward-and-outward pull on the right-hand end of the thread; and with the downward movement` of the thread between said pressure plates still obstructed by the projection II at the inner end of the plate 1, past which it has not yet escaped, all as indicated by the line 5-5 in Fig. 9 of the drawings, in which figure the thread (indicated by the line 5 5), has its right-hand end inclined considerably downward from the point where it is obstructed, or at least,

turned projection I I. This projection also serves to add somewhat to the resistance offered by the pressure plates to the forward movement of the thread before it has as yet been threaded into the regular tensioning device.

The upper corner IIa of this projection II is eased 01T, or slightly rounded, so that as the thread is progressively drawn forward over it, it will gradually work downwardly over said rounded corner by means of the downward pull on the right hand end of the thread; so that the projection II retards the downward movement of the thread between the pressure plates, and also somewhat increases the tension on the thread previous to the threading of the regular tensioning device, both of which are desirable up to this point in the operation of the device. But if this were continued indefinitely, it would hold the tensioning device in the position indicated in Fig. l'1, and would thus defeat the ultimate purpose of the invention by preventing the tensioning device from at the proper time automatically assuming the position illustrated in Fig. 6 of the drawings, in which the tensioning mechanism is shown as properly threaded.

In order to proceed with the operation of the device after the parts have been successfully brought into the position indicated in Fig. '77, attention is now called to some very simple, and

3.45 retarded in its downward movement by the inyet'very ingenious and effective means employed for this purpose: The respective upper portions of the pressure plates 'I and 8 which t in flat engagement with each other, are inclined downwardly-and-outwardly at the entrance end of the plates, as indicated in Figs. 4 and 9; so that as the thread is drawn .outwardly between said flat faces, the action of these inclined ends of the meeting plates tends to draw the thread downwardly as it advances between the plates. When the thread has reached the oifset portion 8a of the plate 8, at the entrance'end of the preliminary tensioning device, and has passed downwardly over the retarding projection II at the exit end of plate l, it easily slips around' the rounded corner VI I a at the lower side ofthe projection II, and suddenly drops intothe ample open space 25 (between the two plates at their lower sides), and rests on the pins I3 which are anchored in the shuttle, and which hold the two plates in operative relation to each other, the plates having bores I2 into which the pins I3 are loosely received. The position of the thread at this time is indicated by the dotted lines near the lower side of Fig. 9 of the drawings. Just before the thread is drawn into this ample open space 26, the parts of the regular tensioning de vice are in the relative position to eachother shown in Fig. 7, with suiicient tension exerted on the thread by the preliminary tensioning device to hold the parts in that position while the shuttle is in motion; but when the thread drops into the open space 2B, the tension on the thread is gone, and the thread passes easily and freely through that open space, and the elasticband 2| suddenly brings the tension bar 2l to the position shown in dotted lines in Fig. 6, and the tensioning device is properly threaded. The fact that the two pressure plates 'I and 8 of the auxiliary tensioning device are spaced apart at their lower sides, causes the two plates to naturally lean toward each other and keep together at the top, aside from the pressure of the spring Si oper'- ating to produce the same result.

From Fig. lO of the drawings it will be seen that the thread in passing from the bobbin to the preliminary tensioning device is inclined upwardly, so that the tendency of the thread to straighten itself as it is fed from the shuttle to the work, exerts a lateral downward pull on the thread in addition to the downward tendency imparted to it by the incline of the meeting plates at their entrance end facing the bobbin. The result of this is that as soon as the forward pull on the thread as it is delivered by the shuttle to the work, drags it downwardly over the retarding projection II, the thread quickly drops down into the ample space 26 at the lower side of the plates, as indicated by the dotted line. This space 26 is clearly illustrated in Fig. 3'of the drawings, which also shows the pins I3 upon which the thread rests when in this space.

As soon as the thread drops down into this space 26, it is relieved of the clamping pressure that had been imposed upon it by the meeting faces of the plates 'I and 8, and that in turn permits the tension bar I'I to be moved by the elastic cord 2| from the position shown in Fig. '7, to the position shown in Fig. 6, which threads the regulartensioning device, all of which has already been fully explained; butit will be seen that if the thread should be'released from the grip of the preliminary tensioning device too soon, i. e., before the thread has been drawn over the ends ofthe shelving fingers 24a, and down into the hooks I9, the tensioning devices will not be threaded when the tension bar IT is swung inwardly by the elastic cord 2li as just described. However, the sooner the tension arm l1 is released after the thread has been drawn over the outer ends of the shelving fingers 24a the better it will be. But of the two, the premature release of the thread by the preliminary tensioning device would lbe much the worse. Therefore, to make it absolutely sure that the thread shall not be prematurely released by the preliminary tensioning device, I provide the modied means illustrated in Figs. 11 and 12. In Fig. 1l, the tension bar Ha has an extension 21 at the left end thereof, which terminates in a short rightangled section 21a which normally takes through the twoelongated registering openings 28 of the meeting plates 'l and 8. This opening is illustrated in Figs. 10, 13 and 14, and is just above the ample thread passage .26 at the lower side of the two plates, and the parts are all so arranged that the bent end 21a, will positively .prevent the downward passage of the thread into the thread passage 26 till such time as the tension bar Ha has moved into the position illustrated Y in Fig. 7, in which the thread has been drawn over the outer ends of the shelving ngers 24a and down into the thread hooks I9. Just at that point the section 21a will have been sufficiently withdrawn from the registering openings 28 to permit the thread to pass unobstructed into the thread passage 26 which, as already stated, is immediately underneath said openings. so that the threading cf the main tensioning device .immediately takes place, as has been already described above.

In Fig. 12 I have shown another very slight modification of the preliminary tensioning device in which I have shown the pressure plate I provided with a struck-out ear 29 upon which is rotatably mounted a spring-pressed lever 3Q having a short right-angled section 3l corresponding to the similar section 21a in Fig. 11. This lever 30 has, at its outer end, a short slightly outturned section 32 terminating in a right-angled bend 33 (see Fig. 13), extending into the path of the tension bar l'la as it moves to the position illustrated in Fig. 7. In this modication, the tension bar Ila, when depressed to the position shown in Fig. '7, will have suiciently withdrawn the section 3| from the registering openings 28 of the meeting plates 'l and 8 to permit the unobstructed passage of the thread into the thread passage 26, as has already been described in regard to the section 21a in Fig. 11.

The spring which presses the lever 3i) is indicated in Fig. 13 by the numeral 34.

The operation of the device has been fully describer as the description proceeded.

From the foregoing, it .will be seen that I have provided a devise of great simplicity, and very eifective in operation; with no parts easy to get broken or out of order; and all cheaply replaceable when worn out.

What I claim as new and desire to protect by Letters Patent is:

1. A loom shuttle having a bobbin chamber, a thread slot, and a tension chamber with springpressed tensioning mechanism therein, and a side delivery eye, the thread `from the bobbin passing into and through the shuttle in contact with the tensioning mechanism, and emerging therefrom through the side delivery eye; and means contacting the thread between the bobbin Vand the ltensioning devices for temporarily resisting the movement of the thread from .the shuttle to the tensioning devices; and means rendered effective by a pull on the free end of the thread against said temporary resistance, for opening the tensioning devices and laying the thread therein; and additional means for, .at .that point, freeing the thread from said temporary resistance, whereby to permit the return of the spring-pressed tensioning devices to their normal position, thereby threading the shuttle.

2. .A loom shuttle having a bobbin chamber, .a thread slot, and a tension chamber with springpressed tensioning devices therein; and a side deliveryeye opening out from said tension chamber; said shuttle being arranged for the passage thereinto of a thread from the bobbin chamber entering the shuttle through the thread slot and passing out through the side delivery eye, said tensioning devices including tranversely disposed shelving fingers underneath the thread slot extending between the sameand the tension chamber and terminating short of lthe Wall of said chamber, whereby to leave a space at the top of said chamber at vone side thereof uncovered by said shelving ngers for the eventual downward passage therethroughof the thread into the tension chamber below, said ngers having runways between them; and said tensioning device in the tensionchamber below having thread hooks extending lupwardly through said runways above the plane Vof the shelving ngers; and means rendered veffective by a pull on the free end of the thread during a fraction only of the time required to complete the iirst flight of the shuttle after thread replenishment for moving the thread over the ends of the free ends of the shelving fingers into the full control of the tensioningvdevices in the chamber below, to be acted upon by said devices.

3. 'In a device of the character described, a

preliminary tensioning device for the thread located 'inthe throatof the thread slot of the shuttle and comprising two A,plates having their upper portions adapted to fit in flat engagement with each other, and their lower portions spaced apart -a -material distance, the extent of the meeting faces of said upper portions in the direction of the longitudinal travel of the thread being materially greater than their vertical extent from ltop to bottom, whereby a section of thread of material length is always in progressive engagement with said meeting faces as the thread passes be tween them; means at the upper part of the exit portion of said meeting faces for progressively flexing the thread as it passes from between the plates whereby to initially increase the'tension on the thread as it passes from the plates to the main tensioning device, said plates having pairs of alined bores in their lower spaced apart portions, and transverse pins passing loosely through said pairs of alined bores with their outer ends anchored in the shuttle, the entrance end of the device, from its top down to the point where its sides are spaced apart, being inclined downwardly and outwardly, said device being designed to have its two upper portions spring-pressed toward each other whereby to adjust the gripping power of said plates on the thread, the spring being designed to adjustably press the plates near their exit ends whereby to adapt their entrance ends to be more easily spread apart for the initial entrance of the thread thereinto.

4. In a device of the character described, apreliminary tensioning device for the lthread designed to be located in the throat of the thread slot of the shuttle, and comprising two plates having their upper portions adapted to fit in `hat engagement with each other, and their lower portions spaced apart a material distance, said plates having pairs of alined bores in their lower spaced portions, and transverse pins passing loosely through said pairs of alined bores with their outer ends anchored in the shuttle, the entrance end of the device from its top down to the point where its sides are spaced apart, being inclined downwardly `and outwardly, said device being designed to have its two upper portions springpressed toward each other, whereby to adjust the gripping power of said plates on the thread, the spring being designed to adjustably press the plates near their exit ends, whereby to adapt their entrance ends to be more easily spread apart for the initial entrance of the thread thereinto, one of said plates being slightly longer than the other and having near its upper side a short inwardly bent section with rounded corners for engaging the thread at its upper side and retarding the downward movement of the advancing thread as it works its way downwardly toward the open space between the plates.

5. In a device of the character described having tensioning devices including a spring-pressed tension bar, a preliminary tensioning device for the thread designed to be located in the throat of the thread-slot of the shuttle, and comprising two plates having their upper portions adapted to t in flat engagement with each other, and

their lower portions spaced apart a material :lis-

tance, said plates having pairs of alined bores in their lower spaced portions, and transverse pins passing loosely through said pairs of alined bores with their outer ends designed to be anchored in the shuttle, said device being designed to have its two upper portions adjustably spring-pressed toward each other whereby to adjust the gripping power of said plates on the thread, the spring being arranged to press the plates near their exit ends, whereby to adapt their entrance ends to be more easily spread apart for the initial entrance of the thread thereinto, said plates having a pair of registering openings at the lower sides of their meeting faces just above the open thread space at the bottom of the plates; and a stop pin arranged to pass into and out of said openings to alternately open and close the downward passageway between the two plates, said stop pin being correlated to the spring-pressed tension bar of the shuttle to move synchronously therewith, and arranged to withdraw said pin from said registering openingsV when the tension bar is moved into position to open the tensioning devices for the reception of the thread thereinto, and to return the pin into said openings when the tension bar is moved to its normal thread tensioning position, whereby when the tension bar is moved into position to open the tensioning devices, the passageway between the plates is opened for the thread to be passad downwardly between them into the open thread space below, thereby relieving the tension imposed upon the incoming thread when pressed between said plates, and permitting the tension bar to return by its own spring pressure to its normal tensioning position, and thus leaving the regular tensioning device in full control of the thread as it is fed to the work.

6. In a self-threading shuttle having a main tensioning device including a spring-pressed tension bar movable into tensioning and non-tensioning position, and standing normally in tensioning position, a preliminary tensioning device located between the bobbin and the main tensioning device; and intermediate mechanism between said spring-pressed tension bar and said preliminary tensioning device for correlating the movements of the two tensioning devices, whereby the' located between the bobbin and the main tensioning device, and having at their upper portion smooth iiat faces adapted to meet in face-to-face engagement with each other, the device being adapted to receive the thread at its upper edge between said flat faces, said plates being springpressed toward each other to cause them to yieldingly grip the thread as it passes between them from the bobbin to the main tensioning device, and having their edges, which face the bobbin, inclined downwardly and outwardly, whereby to impart to the thread a tendency to feed downwardly as it is drawn between the plates in passing from the bobbin to the main tensioning device, the opposing sides of said plates, immediately beenath these meeting faces, being spaced-- apart to form an ample passageway for the thread after it has fed downwardly thereinto from between the meeting faces at the upper sides of the two plates, said meeting plates, just above said ample passageway for the thread, being provided with means for blocking the downward passage of the thread between said plates till a predetermined point has been reached in the operation of the main tensioning device, and for opening said passageway when another predetermined point in the operation of the main tensioning device has been reached.

8. In a device of the character described, the combination with a main tensioning device, of an auxiliary tensioning device comprising two plates located between the bobbin and the main tensioning devices, and having at their upper portions smooth flat faces adapted to meet in faceto-face engagement with each other, the device being adapted to receive the thread at its upper edge between said flat faces, said plates being spring-pressed toward each other to cause them to yieldingly grip the thread as it passes between them from the bobbin to the main tensioning device, and having their edges, which face the bobbin, inclined downwardly and outwardly, whereby to impart to the thread a tendency to feed downwardly as it is drawn between the plates in passing from the bobbin to to the main tensioning device, the opposing sides of said plates, immediately beneath these meeting faces, being spaced apart to form an ample passageway for the thread after it has fed downwardly thereinto from between the meeting faces at the upper sides of the two plates, said meeting plates, just above said ample passageway for the thread being provided with means for positively opening and closing the passageway between said plates when respective predetermined points have been reached in. the operation of the main tensioning device, the extent of the meeting faces ofv said upper portions ofthe auxiliary plates in the direction of the longitudinal travel of the thread being materially greater than their vertical extent from topto bottom, whereby a section of thread of material length is always in progressive engagement with saidv meeting faces as the thread pas'ses between them.

9. In. a self-threading shuttle, a draw-back tensioning device havinga member movable in one direction into its open position for the reception of the thread, and in the opposite direction into its operative position for tensioning the same, said member being spring-pressed in a direction to hold it normally in its tensioning position; and means actuated by the initial movement of the ii'r/st pick of the shuttle after threadreplenis'hme'nt for temporarily tensioning the thread,

and by virtue ofsuch tension for moving said 20 each other with the thread passing between them,l

the edges of said upper portions of the plates facing the bobbin being inclined downwardly and forwardly, and the extent of the meeting faces of said upper portions of said plates in the direction of the longitudinal travel of the thread beingv materially greater than their vertical extent from top to bottom, whereby a section of thread of material length is in progressive engagement with said meeting faces as the thread passes between them.

JOSEPH B. PLEVYAK.

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