US2589429A

US2589429A - Device for tensioning the weft thread in looms

Info

Publication number: US2589429A
Application number: US711100A
Authority: US
Inventors: Pfarrwaller Erwin
Original assignee: Sulzer AG
Current assignee: Sulzer AG
Priority date: 1945-11-24
Filing date: 1946-11-20
Publication date: 1952-03-18
Anticipated expiration: 1969-03-18

Description

March 18, 1952 E. PFARRWALLER DEVICE FOR TENSIONING THE WEFT THREAD IN LOOMS Filed NOV. 20, 1946 4 Sheets-Sheet l INVENTOR:

ERW/N PFARRWALLER BY 4- g4;

ATTOR EY March 18, 1952 E. PFARRWALLER 2,589,429

DEVICE FOR TENSIONING THE WEFT THREAD IN LOOMS Filed Nov. 20, 1946 4 Sheets-Sheet 2 Fig.3

I N VEN TOR:

ERW/N PFA RPM/ALLEP BY ATTO EY March 18, 1952 E. PFARRWALLER 2,589,429

DEVICE FOR TENSIONING THE WEFT THREAD IN LO OMS Filed NOV. 20, 1946 4 Sheets-Sheet 5 V W 8% g m 'I a Q 1 r X D A L 4.0, a N '0 0% Q0.) Nice 0 INVENTOR:

E RW/N PFARRWALLER A TTO EY March 18, 1952 E. PFARRWALLER 2,589,429

DEVICE FOR TENSIONING THE WEFT THREAD IN LOOMS Filed Nov. 20, 1946 4 Sheets-Shet 4 INVENTOR. ERWINPFARRWALLER.

ATTORNEK Patented Mar. 18, 1952 DEVICE FOR TENSIONING THE WEFT THREAD IN LOOMS Erwin Pfarrwaller, Winterthur, Switzerland, as-

signor to Sulzer Freres, Societe Anonyme, Win.-

terthur, Switzerland Application November 20, 1946, Serial No, 711,109 In Switzerland November 24, 1945 The present invention relates to a method and means for tensioning the weft thread in a loom.

Among the objects of the invention are to tension yarn or thread in a gripper shuttle loom in order to give the desired quality or characteristic to the finished cloth, to accomplish the ten- Sioning reliably at relatively high speed and in coordination with the operations performed by other parts of the loom mechanism, to present tensioned yarn for the beat-up operation, and to control weft-tension and draw off yarn from the bobbin simultaneously. In carrying out the method, so much of the weft thread is pulled bacl; at the inlet side of the shed that not only is the desired thread tension obtained, but also Y weft thread is drawn off from the supply bobbin. The method may be carried out by means of a pull-back device arranged at the inlet side of the shed, this device being controlled by the loom drive in such a way that weft thread material is not only drawn back from the shed, but also drawn from the bobbin, j r

Further and other objects of the present invention will be hereinafter set forth in the accompanyin specification and claims and shown Fig.3 is' a top view of the detail shown in Fig. 2;

Figs. 4 and 5 are part-sectional side views of another detail of the mechanism according to the invention.

Fig. 6 is a diagrammatic illustration of a mechanism forming plat of the system shown in Fig.4.

In performing the method in accordance with a preferred form thereof, on a loom of the gripper shuttle type, a source of Weft thread material such as a bobbin I is provided outside of the shed. As shown schematically in Fig. l, the bobbill I is arranged at the picking side A of. the

10 which is entry side of the shed m. The

end I3 oi the thread is projected through the shed It to the receiving side 13. In order that 18 Claims. (Cl. 139-126) the end It may be projected readily through the shed III, a loop is formed in the portion of the thread between the bobbin I and the end I8 be: fore the .end I3 is projected through the shed. This loop is represented in diagram I of Fig. l by a portion of the thread extending to the point 51). As the end I8 is projected to thepoint I841, as shownfin-diagram II, the loop is taken up and additional thread is drawn from the 0011? bin I.

If a shuttle such as a gripper shuttle 9 is emf ployed for projecting the thread end l8 through the shed it, there tends to be some overshoot, which is irregular. For the sake of uniformity, the end. it is brought back to a fixed point shown at Ifib in the diagram III. The resultingslacl; is taken up by forming a small loop and drawing the thread back to the point 50,. The thread is 'then'gripped by a holding and positioning .de-. vice 2 at the entry side of the shed I0 and soy-.- ered at the point 22, by a cutting device where:

upon the weft thread is beaten into the shed while it is still under tension, the cut ends having been held. The shed is then closed and a new shed is formed. The thread end 22 is then returned to the point 22a bysaid holding and positioning device and attached to a new shuttle and released by said holding device preparatory to being projected again through the next shed. Inreturn the thread end 22 to the point 22a, the size of the loop in the portion of the shed between the bobbin I and the end 22a is increased by drawing the thread back to the point 5?), shown in diagram V of Fig. l. The increase in size of the loop is such that not only is the distance 23 between the

points

22 and 22a taken up, but additional material is also drawn from the bobbin I in forming the loop of increased size.

The loop to the point 52) is preferably released at the same rate as the end I8 is drawn out ior projection through the shed I9 so that no slackness the thread is permitted to develop. Preferably, after the material of the loop has been taken up in projecting the shuttle 9 with the thread end I8 through the shed I0, sufficient braking is applied to the thread drawn from the bobbin i to maintain the same tension.

The mechanism shown in Fig. 1 includes in addition to the bobbin 5, a guide eye 3, a first thread brake i, a thread pull-back 5, and a second thread brake E. Beyond the brake 6 is a further guide eye I followed by a shuttle-feedin thread 2 While it is being inserted into the shed III. The holding and positioning device 8 may be constructed according to Figs. 1 to 4 of the U. S. Patent No. 2,163,760 to A. Moessinger. On the pin It is mounted the picking stick I I, which is shown in detail in Fig. 4 and is operatively connected with the loom drive; by means of this stick the shuttle 9 is picked through the shed I and moves past the thread cutter I2 and past the thread clamp I3 before entering the shed I0. At the shuttle receivin side B of the loom the shuttle 9 passes another thread clamp I5 before it enters the shuttle brake l6, where it comes to rest in position 9a.

Since it is difficult to bring the shuttle 9 which arrives at great speed at the side B, exactly into the position which corresponds to the position ofthe weft thread 2 before it is beaten into the fabric, the shuttle 9 is permitted to move beyond the ultimate position of the end of the weft thread by a distance 2I which is not necessarily constant. The shuttle 9 is then pushed back into its proper end position 9b, within the shuttle brake, by means of a pushing device I"! which may be coupled to the loom drive as shown in Fig. 5. 'After the shuttle 9 has released the weft threadZ when in its end position 917, it is brought out of the picking path into a position 90 and then carried back into the position M, from where it comes again into the picking path to effect another insertion of the weft thread 2 into the shed I9. For efiecting the aforedescribed movements of the shuttle a mechanism may be used as disclosed in United States Patent NO. 2,420,380 of May 13, 1947.

The operation of the parts described so far is as follows: e

The thread brakes 3 and 6 are opened when the shuttle 9 is picked into the shed ID. The thread pull-back device 5 is in its extreme outside-position 511 while the thread 2 takes up the position indicated by I in Fig. l. The end I8 of the Weft thread 2 is firmly gripped by the shuttle 9. When the shuttle is picked by means of picker II the thread pull-back device 5 begins to move inward in the direction of the arrow I9. The picker II and the thread pull-back device 5 are operatively interconnected andthe back swinging motion of the thread pull-back device is effected in dependence on the time of the pick or on the picking speed of the shuttle by a mechanism, for example as shown in Figs. 2 and 3.

The inward-movement of the thread pull-back device 5 may be of such an extent that the .reserve length of weft thread released thereby corresponds approximately to the first part of travel of the shuttle 9 which is only a fraction' of the total length of an inserted weft thread. In order to ensure coordination of the inward-movement of the thread pull back device and of the picking movement or of the picking speed of the at the moment when the thread pull-back device 5 has arrived in the axis of thepicking path of the shuttle 9; because of this, the weft thread 2, drawn from the bobbin I while being inserted into the shed It], does not deviate from the straight path, or deviates only slightly. As soon as the shuttle 9 arrives at the receiving side B in the shuttle brake IB and before its speed is slowed down, at least one of the thread brakes 4, 6. comes into operation to prevent the kinetic energy of the moving weft thread 2 from causing a superfluous amount of thread to be drawn from the bobbin I, which would result in the weft thread running loose inside the shed I0 and forming loops and waves.

When the shuttle 9 comes to rest in the position 9a, the weft thread 2 is in the extended position 2a shown in II in Fig. 1. The thread pullback device 5, operated for instance by the means shown in Figs. 2 and 3, moves in the direction of the arrow 29, whilst at the same time, with the thread brake 4 closed, the pushing device I! transfers the shuttle 9 into position 91) and the end of the weft thread 2 from position I8a to I8b as shown in II and III in Fig. 1. The movement of the pushing device I! which is caused for instance by the means shown in Fig. 5, and the outward movement of the thread pull-back device 5 which may be effected by the mechanism illustrated in Figs. 2 and 3, are coordinated and not only is the thread pull-back device 5 pushed outward by a distance necessary for tightening the weft thread 2 when the weft thread end is moved back from position l8a to I81), but also more weft thread material is drawn from the stock, i. e. from the bobbin I through the brake 4.

The extent of push-back movement of pusher I1 and of swing-out movement of thread pullback device 5 are so coordinated that the former is smaller than the length of thread pulled out by device 5 minus the clearance between the two brakes 4 and 6. Start and completion of both movements may coincide. However, the grooved member 'I'I shown in Fig. 5 which will be described later, may be set so in relation to the setting of cam 21 in Fig. 2 that the pull-back device 5 is actuated before actuation of pushback member I I. Members II and 2'! are both driven by the main shaft of the loom. With this adjustment the thread puller 5 pulls some thread from the supply I before. it pulls thread back from the shed and tensions it in coordination with the pusher I1. Relative operation of pusher I! and puller 5 may be so adjusted that both begin to operate at the same time but that, after the thread end has moved from position IBa to position 58?), Fig. 1, and the thread puller .5 has moved fro-m position 5 in operating step II to position 5a" in step III, the stroke of puller 5 is not yet completed and that completion of the stroke causes not only tensioning of the weft thread but also pulling of thread from its source of supply. The shuttle brake I6 prevents pulling Of the thread end I8, which is held by the shuttle, beyond point I8b.

The tension of the thread 2 in the

positions

2a and 2b in Fig. 1 depends on the setting of the brake t. However, with a more powerful action 1 of brake 4, the tension in the weft thread 2 is greater, and with a weaker brakin action itis less. In the position 2b shown in'III in Fig. 1,

' the weft thread 2, adjustably tightened, is 1 gripped by the two edge grippers I3 and I5 and taining the tension given to it with-the help of the,

braked. Through this control of the tension of the weft thread to be beaten up into the fabrie,.

th'equality of the fabric can be influenced greatly and suited to the use. for which it isintended.

3 Thedevice 8, which was moved into position- Ba'by means, for instance as shown in Fig. 4 and operated by the loom drive, returns the new end 22 of theweft thread 2 by the length 23 to p sition' 22a, whilst at the same time the thread pull-back device moves from position 5a in the direction of the arrow 20 into the position 52), as illustrated in IV and V in Fig. 1. The speed at which the device 8 moves back from the position 8a into the initial position and the speed at which the thread pull-back device 5 moves from 50. to 5b, are coordinated and in this phase of operation not only is the weft thread 2 securely held under tension by the brake 4 and the device 8,'but also additional weft thread materialis drawn from the bobbin I through the closed brake 4 which retards the movement of the thread but does not stop it.

Thereby, also in this phase of operation, illustrated by IV and V in Fig. 1, a tension in the weft thread is created and maintained which is dependent on the setting of the brake 4. As soon as the end of weft thread 2, which is drawn back from shed H] and away from brake 4, ar-

during the pick, a supply of loose thread is made available facilitating acceleration of the shuttle and preventing jerks on the thread running off the bobbin.

The described method not only prevents any wear on the thread in the weaving operation, but the-thread is also better protected and the duality of the fabric can be controlled. The braking of the weft thread 2, with the shuttle 9 in the receiving brake l6 and at the return motion of the weft thread 2, may be effected by brake 4 alone which is arranged between the bobbin l and the thread pull-back device 5, or by the two brakes 4 and 6. If two brakes are used, they may be coordinated with respect to the time at whichthey operate and to the intensity of their operation.

As shown in Figs. 2 and 3, the thread pullback device 5, diagrammatically illustrated in Fig. 1, may be provided with a one-arm swinging lever '24 which is pivoted on a stationary pin 25. The free end of the lever 24 is fitted with a hook 25, through which the weft thread 2 passes. A cam follower 29 is rotatably mounted on the lever 24 by a pin 38. This cam follower cooperates with a cam 21, which is fixed on the shaft 28 of the loom drive. A piston rod 33 is pivotally attached to the lever 24 and extends into a cylinder 35. A piston 3lis fixed to rod 33 within cylinder 35 and loaded by a pressure spring 32 resting on an adjusting screw in the cover of the cylinder. In the lower part of the cylinder 35 aybcre 34 is provided which is covered by ,the piston '31 when the latter approaches its lowest end position.'- v r Movement of the pull-

back device

24, 26 in the direction of'the'arrow 20 to the extreme outward position 2411, shown in dash-dot lines, is efiected by'the cam 27 against the action of the spring 32.

which is tensioned by the piston 31 moving to ward its upper end position. The run' ofi side, 21d of the cam 21 is so steep, i. e..radial, that the:

inward movement of the pull-back device 24', '26 in the direction of the arrow I9 is efiected solely under the action of the spring 32' and'riis independent of the speed of the drive shaft- 28 and therefore also independent of the speed of- .the. loom drive. I 1

Since not only the speed of the movinginmotion of the thread puller 24 but also the picking speed of shuttle 9 are independent of the speed of rotation of the loom drive, the former speed may be coordinated to the initial picking speed of the shuttle by proper adjustment of the initial tension of spring 32, Fig. 2,'and spring 88, Fig. 4,. to be described later, and the length of thread pulled by the shuttle at the beginning of the pick is provided by the moving-in motion of the thread puller without withdrawal of thread (rom the supply 1.

Shortly before the pull-

back device

23, 25

reaches its initial position, whereby the weft.

(Fig. 1), the movement of the pull-back device- 24, 26 is pneumatically retarded, the piston 31 covering the bore 34, whereby the air under the piston 3| can escape only slowly or not at all, and is therefore compressed.

Return motion of the pull-back device 24', 26 into the initial position by a force whose magnitude is independent of the loom drive, such as a sprin s, is particularly recommended when the shuttle 9 is picked by a force whose magnitude is also independent of the loom drive, for example by the use of a picking device as shown in 4". On the other hand, if the pick of the shuttle' is'effectedby means of a cam operated'bythe loom drive, it ispreferable to control the weft release movement of the pull-back device, i. e; movement of

lever

24, 25 from the extremeoutward position 24a into the initial position; by a or an eccentric drive instead of b spring 32-1 The brakes 4', 6 shown diagrammatically in 1 have each a brake arm 35 as shown inj'Figs. 2 and 3 which is pivoted on the fixed-pin 3! and provided with a tension spring '48. On eachbrake arm 35 a brake shoe 38 is arranged which is" pressed under the action of the tension spring 45! to a soft body which is held taut, for instance tothe braking belts and the brake shoe 3B." The endlessbraking belts 39 ext nd around a driving roller 48 and a tension roller lll. The two driving rollers M! are fixed on asha t 42 provided with a ratchet wheel 43 into which fits a'pawl 44. The pawl is conne ted to a tipping lever 46' by means of pm 4'5: the tipping lever is pivotably mount ed on stationary pin 41. The tipping lever 46 and the swinging lever 24 are pivotably connected to the operating rod 69. Each swinging motion 7 of the lever 24 causes a rotary motion of the driving roller 48, whereby the brake belts 39 are intermittently moved relatively to the brake shoes 38 In this way concentration of wear at a single point of the braking belts 39 by the weft thread 2 Each fork 5i is "under the action of a tension.

spring 53 whose pullcan be adjusted-by r'ne'a'ns of screws 5d for setting'the'tension-ofthe'brak belts ligand consequentlythe'brakiri-g action on theweft thread 2. I i w e In each of the two brake arms 36 a cam fol lower 55- isfitted by means of a pin 38' and is pressedzagainst a cam. 55 by the action of the springs 48. The two cams 55 are fixed on the shaft vL28 of the loom drive. The motion of the brakeshoen 38 and theoutward motion of the pull-

backjzdevice

24, 26 in the direction of the arrow 28' are dependent on the motion of the cams'i55 and 21 respectively and are thereby de pendent on the speed of the loom drive. The timingof the motions of the pull-

back device

24, 26 and" of the brake arms 36 with respect to each otherris determined by theqrelative position of the

cams

21 and 55 and may be changed by alteringtheir relative positions. With this arrangement-it is not only possible to adjust the brake force-acting on the weft thread by suitably increasing ordiminishing the tension in the brakingi.belts'39, but also to adjust these brake pressures "within each operatingcycle by suitably shaping the cams 55 and setting their relative .as 'well as adjustment and maintenance of the tension when the weft thread 2 is beaten up into the fabric. I

.Fig. 4 illustrates the positioning device 8, which, asshown diagrammatically in Fig. 1, transfers the weft thread end 22 from position IV to position-;V (22a). Device 8 is held by a guide piece 51 which is slidably supported between the guides 59 arranged on two sides of the shuttle 9. The guide piece 51- is connected to a driving lever 6| pivoted on'the fixed pinBO by a link member 58. At one end of the lever 6| a cam follower 62 is arranged runningin cam groove 63 of a control cylinder-64. The control cylinder 84 is mounted on the shaft- 28 of the loom drive. By suitably shaping of" cam groove 83 and a relative proportioning of the length of the arms of the lever 6|, the movement of device 8 may be made to that the stroke of member 5 (26) is not yet com-- pleted when that of device 8 is completed, or that member 5 begins to move before device 8'has brought the thread end 22 into the position 22a. Duration of action of both motions may be the same.

Fig. 6 is a diagrammatic illustration of a weft thread gripping and positioning device as may be used in the mechanism according to the present invention. One the left side of Fig. 6, the device isshown in the position shown on top of Fig. '1 and designated by 22a at the bottom of said figure. 7 In this position the grippers 9 of shuttle'9 have just been closed on the thread 2 and the thread is still held by the grippers 8 of the positioning member 51. Up-strokev of rod 88'preliminarily to the release of the shuttlepicking means causes clockwise movement of the gripper- .openin'g lever 8'-as indicated by arrows in Fig. 6.

When this lever reaches a position at rightangle to the longitudinalaxis of the grippers, the; lat- This is acter are opened and permit the shuttle to move to the right trailing a weft thread. Member 51- is then also moved to the right to the position and in the condition shown on the right side of Fig. 6, i. e. with the grippers open. When the;

pick is completed, the thread cutter l2 comes into action and closes the grippers 8 prior to severing the thread. Downward movement of a cutting member 12 causes member 8 to be turned counter-clockwise as indicated by arrows on the right side of Fig. 6. After the thread has been cut,v

' the shuttle is moved into the channel to assume the position in which it is shown in *Fig; 6. The. pin is withdrawn for closing clamps 9' upon the;

thread 2. The mechanisms shown in Fig. 6 are conventional and are illustrated only because such mechanisms are suitable for use in a mechanism according to the invention.

The. picker II is pivoted on the shaft l4 and. provided-with an arm 12 which .is joined to a link 13, Through the joint 15 the link 13 is connected to a second link 14, which is pivoted on a stationary pin 16. A tensioning lever I1 swings about a pin '18 and is fulcrumed at its end 19 to a pushrod 88. The push rod 80 has at its free end a cam follower 8| which is pressed to a cam 83 by means of tension spring 82 attached to the push rod 80; the cam 83 is fixed on shaft 28 of the loom drive. 4 Push rod 88 is provided with anabutment 89. This cooperates with one arm of bell-crank lever 84, whose second arm acts on the joint pin 75. A strong tension spring 88 acts on .the picker I]; it imparts the necessary acceleration to the picker I I when picking.

In Fig. 4 the position is shown which the picking device takes up shortly before the shuttle '9 is picked. If now,the shaft 28 of the loom drive rotates, the push rod 80, due to the pulling action of the spring 82, moves upwards to follow a corresponding movement of the cam 83. The stop 88 presses on the bell crank lever 84; the movement of which presses the lever pair 13, 14 into its extended position and then in the diIQO-r tion of the arrow 86 into flexed position whereby spring 88 is released and the picker l I accelerated in the directionof the arrow 81. The shuttle 9 is moved there-by at great speed between the open thread cutters l2 and past the thread gripper is into the shed I 8, whilst the picker ll comes torest in the positionllabecause of a stop 90. The cam 83 then presses the push rod 88 down against the action of. springs 82 and 88,;

whereby the tensioning lever 11 is swivelled into position we and the spring 88 is tensioned. This causes not only straightening of the

link pair

73, 14 but also imparts sufficient kinetic energy to cause it to come to rest on a stop 85 in aposition slightly flexed toward lever 84. Further rotation of the cam 83 permits push rod to be moved upward by the spring 82 into the intermediate position shown in the drawing whereby the tensioning lever 11 is swivelled out of the path of motion of the picker l i and the latter remains locked in the position ready for the pick. Further upward moving oiv the push. rod 80 caused by the spring 82 and the position of the cam 83 initiates the next pick. f

In the same manner as the device 8 in Fig. 4 the pushing device 17, shown in Fig. 5, can be actuated from the shaft 28 of the loom drive.

anew

. 9 The pushing device I! moves the shuttle S from its ultimate position 90; back to position -9b. The pusher member I! travels in a guide 65. To the pushing device I! a link member 66 is jointed which is connected to an operating lever 61. The

operating lever 67 is supported by a pin 68 and has at its free end a cam follower B9. The latter fits into a cam groove in a control cylinder II. This control cylinder II is fixed on the shaft 28 of the loom drive. As in the case'of the drive shown in Fig. 4 the shape of the cam groove 10 and the ratio between the length of the two arms of the lever 67 may be chosen in such a way, that in spite'of thefweft thread moving from position II to position III (Fig l') in addition to the length of thread: needed for tighteningthe weft thread, alsosom'e weft thread material is drawn off from the bobbin I by the thread pull-back device ii. a 7

While I believe the above described, embodiments of my invention to be preferred embodiments, I wish it tobe understood that I do not desire to be limited to the exact details'of design and construction shown .and described, for obvious modifications will occur to a person skilled,

inthe art.

I claim:

1'. In a loom for weaving, the combination of drive means, a stationary source of weft'thr'ead supply, a shuttle, two positivelyactuated weft thread retarding means, weft thread pull-back means disposed between said retarding means and moving substantially reciprocatin'gly and transversely to the line connecting'said retarding 2. In a weaving loomof the typeha'ving aweft.

thread bobbin, a shuttle movable substantially in a line away from the bobbin for carrying .7 thread through a shed, and a loom drive shaft,

the combination comprising a thread'pull-back lever between the bobbin and the'shed having a hook. through which thread is adapted to pass, a cam on said drive shaft engaging said lever for oscillating the lever synchronously withdrive shaft rotation-in a plane transverse to the line of motion ofthe shuttle, a weft-thread brake between the bobbin and the pull-backlever, having a brake surface and a movable brake shoe bea tween which thread may pass, and a cam on'said drive shaft engaging said brake shoe for oscillatmg said brake shoe synchronously with said drive shaft rotation, said brake being so located relativetothe thread hook of the said pull-back lever that the brake forms a guide for the thread. causing the thread to form a. loop while said hook moves away from the l-ine'ofmotion-of; the

shuttle. .7

3. In aweaving loom of the type having a weft thread-bobbin, a gripper shuttle movable substantially in a line away from the bobbin for I carrying thread through a;shed,,and aloom drive shaft, the combination comprising cam means on the shaft, a shuttle-feeding-Weft thread gripper disposed between said bobbinand the shed .and guided to move inthe line of movementof the shuttle and having operating mechanism driven by said cam means, said mechanism serving to translate rotary motion of the shaft into reciprocating movement of the said" gripper'jtoward and from the shed, a'thread pull back lever between the bobbin and the weft-thread shuttle-feeding grippenhaving a part through which thread is adapted to pass, and a cam on said drive shaft engaging said lever for oscillatin'g, thelever synchronously with drive shaft rotation in'a' plane transverse to the lineof motion of the shuttle, said cams being so located on said shaft that the part of the said pullback lever, through which the thread passes,

1 moves away from the line'of motion .of the shuttle while'the'said gripper holds the thread and moves it away from the'sh ed'.

4. In a weaving loom of the type having a -loom drive; shaft, a weft thread'bobbin, and a shuttle movable substantially in a line away fr8m the bobbin for carrying thread through ashed, the combination comprising a shuttle picker at the side of the shed near the bobbin, actuating mechanism for the shuttle picker, a cam on said drive shaft engaging said picker actuating mechanism,

a shuttle push-back lever at the far side of the shed, a cam. on said drive shaft engaging said lever for moving the-shuttle back to a fixed position froman overshot position, a thread-pullback lever between the bobbin and the nearsid-e of the shed having a hook through whichthread is'adapted to pass, a cam on said drive-shaft engaging said pull-backlever for oscillating the lever synchronously with drive shaft rotation in a plane transverse to the direction of motion of the'shuttl'e, a weft-thread brake between the bobbin and the pull-back lever, having 'a brake surface and movable brake shoe between which thread may pass, and a cam on said drive'shaft engaging said brake shoe for oscillating said brake shoe synchronously with'said drive shaft,

said cams being so located that the thread hook of the said pull-back lever moves away from the line of motion of the shuttle as the shuttle-push backflever moves the shuttle at the farside of the shed to its fixed position, andwhile thethread brake shoeis moved to the brake surface-for retarding run-off of weft thread from the bobbin while said hook pulls on the thread for taking up the slack caused by theback-movement ofthe shuttle, without stopping said run-off.

5. In a loom for weavin the combination of loom drive means, a source of Weft thread. supply,

warp threads forming a shed, a weft thread pull back mechanism disposed at the side of the shed where the weft thread enters it when being inserted and including, a cam rotated by said loom drive, a lever having an end portion adapted to engage a weft thread, a cam follower mounted on said lever and engaging said-cam, and spring means holding said cam follower to said cam, the pulling of the weft thread being, effected in, positive-relation to the configuration of the cam.

6; Ina loom for weaving a weft thread pull back mechanism as defined in claim 5-,v said- 0am I being so formed as to positively move said'lever in a direction forpulling the weft thread and to afford return movement of said'lever toinactive position by means of said spring. 1

7 In a gripper shuttle loom having loom drive means, a source of weft thread supply, and warp threads forming a shed, the combination of-qa weft"; thread pull back device disposed at the; side pf the-shed where the weft thread enters it when completion of the pick.

exclusively in the line of the weft thread enter- W ing the shed and disposed at the same side of .the shed as said pull back device and also connected to and driven by said loom drive to move reciprocatingly at interdependent timing with said pull back device.

' 8. In a loom for weaving, the combination of loom drive means, a shuttle, a shuttle picking mechanism comprising resilient means periodically tensioned by said drive means and released and picking thereby the shuttle with an accelerating force independent of said drive means, a Weft thread pull-back mechanism comprising actuating means connected to and operated by said loom drive means and comprising other resilient means tensioned upon actuation of said pull-back mechanism bysaid actuating means and released and returning thereby said pull-back mechanism to inactive position by a force independent of said drive means, and individual adjusting means connected individually with said resilient means and controlling their tension.

9. In a loom for weaving, the combination of loom drive means, a shuttle, a shuttle picking mechanism comprising resilient means periodically tensioned by said drive means and released and thereby picking the shuttle with an accelerating force independent of said drive means, and a weft thread pull-back mechanism comprising actuating means connected to and operated by said loom drive means and comprising other remeans, weft thread motion retarding means, said three last mentioned means individually comprising actuating means connectedwith and actuated by said drive "means and operated at interdependent timing, said actuating means being so constructed as to release said retarding means at'the start of the pick and to apply same before completion of the pick.

11. In a lo'om' for weaving, the combination of drive means, a stationary source of weft .thread three last mentioned means individually comprising actuating means connected with and actuated by said drive means and operated at interdependent timing and being adapted to release said retarding means at the start of the pick and to apply same substantially simultaneously with the 12. In a loom for weaving having loom drive means, a source of weft thread supply, warp threads forming a'shed, the combination of a "and simultaneous withdrawal of weft thread from said source.

'13. In a loom for weaving having loom drive means, a source of weft thread supply, warp threads forming a shed, the combination of a weft thread pull-back device and a weft thread motion retarding device, both devices being disposed and acting on the weft thread between said source 'and the side of the shed where the weft enters when being inserted, a mechanism connected to and driven by said drive means and connected to and positively actuating both said devices at interdependent timing, said retarding device comprising two clamping means spaced along the line of movement of the weft thread toward the shed and engaging the thread, and said pull-back device having a member disposed between said means and movable transversely to the line of movement of the thread toward the shed for pulling the thread to form substantially a triangle when said member is moved from said line of movement, the corners of the triangle being formed by flexing the thread at said means and atsaid member.

14. In a weaving 100m having warp threads forming'a shed, a source of weft thread supply disposedoutside the shed, a shuttle transporting weft thread from said source through the shed,

. and a loom drive, the combination comprising a weft thread pull-backdevice disposed between said source and one side of the shed and engaging the weft thread and being adapted to pull weft thread from the shed and also from said source, a shuttle push-back device disposed on the other side of the shed for pushing the shuttle from anovershot position back to a fixed position, actuating means individually connected with said pull-back and with said push-back depositioning means disposed between said pullsupply, picking means, weft thread pull-back 'means, weft thread motion retarding means, said weft thread pullback device and a weft thread motion retarding device, both devices being disposed and acting on the weft thread between said source'and the side of the shed where the weft enters when being inserted, and a-mechanism connected to and driven by said drive means and connected to and positively actuating both said devices at interdependent timing'and being so constructed as to afford withdrawalfof weft thread in a direction away from the shed back device and the shed, weft thread severing means disposed between said positioning means and the shed and severing the weft thread after it has been gripped by said gripping'and positioning means, actuating means connected with said positioning means and the loom drive and moving said positioning means witha gripped shaft, the combination comprising cam means on the shaft, a shuttle-feeding weft-thread gripper disposed between said bobbin and the shed and guided to move in the 'line of motion-of the shuttle and having .an operatin mechanism' driven by said cam means, said mechanism serving to translate rotary motion of 'the shaft into reciprocating movement of the said gripper toward and from the shed, a thread pull-back lever between the bobbin and the weft-thread shuttlefeeding gripper, having a part through which thread is adapted to pass, and a cam on said drive shaft engaging said lever for oscillating the lever synchronously with drive shaft rotation in a plane transverse to the line of motion of the shuttle, a weft-thread brake between the bobbin and the pull-back lever having a brake surface and a movable brake shoe between which thread may pass, and a cam on said drive shaft engaging said brake shoe for oscillating said brake shoe synchronously with said drive shaft, said cams being so located on said shaft that the part of the said pull-back lever, through which the thread passes, moves away from the line of motion of the shuttle while the said gripper holds the thread and moves it away from the shed and said brake affords simultaneous pulling of thread from the bobbin.

17. In a loom for weaving having warp threads forming a shed, a source of weft thread supply disposed outside of the shed, loom drive means, and gripper shuttles, the combination of picking means for said shuttles, a weft thread pull-back device, weft thread cutting means, and a weft thread holding and positioning device guided to move in the line of movement of said shuttles, said devices being connected with and interdependently operated by said drive means, said holding and positioning device being adapted to move the end of a weft thread from the shed toward said source after it has been out by the cutting means after the pick and said pull-back device being adapted to pull back the moved weft thread and to pull an additional length of weft thread from said source.

18. In a loom for weaving, the combination of weft threads forming a shed, a source of weft thread supply disposed outside of the shed, loom drive means, picking means, a weft thread pullback device, weft thread cutting means, a weft thread holding and positioning device, and actuating means interconnecting said devices and said drive means for interdependent operation thereof and bein adapted to actuate said holding and positioning device to move the end of a weft thread from the shed toward said source after it hasbeen cut by said cutting means after the pick and to actuate said pull-back device to pull back the moved weft thread and to simultaneously pull an additional length of weft thread from said source.

ERWIN PFARRWALLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 375,335 Bowker Dec. 27, 1887 448,202 Bowker Mar. 17, 1891 805,751 Renger Nov. 28, 1905 1,923,954 Rossmann Aug. 22, 1933 2,089,620 Rossmann Aug. 10, 1937 2,160,339 Moessinger May 30, 1939 2,163,760 Moessinger June 27, 1939 2,407,773 Fletcher Sept. 17, 1946 2,420,330 Moessinger May 1 3, 1947 FOREIGN PATENTS Number Country Date 369,694 Great Britain Mar. 31, 1932 449,557 Great Britain June 30, 1936 678,468 Germany July 15, 1939 703,304 France Feb. 3, 1931 790,166 France Sept. 2, 1935