US3565121A - Weft selecting and presenting apparatus - Google Patents

Abstract

Several differently colored weft threads are fed through brake means and tensioning means to a gripper shuttle in an order determined by a pattern. Only the selected thread is clamped by the brake means and tensioned by the tensioning means during insertion into the gripper shuttle, and after the pick of the shuttle, while untensioned and unclamped thread is fed to the gripper shuttle during weft insertion. The nonselected threads remain untensioned and are not clamped, but slightly braked and are guided in accordance with the movement of the woven fabric.

Description

United States Patent [72] Inventors Vladimir Svaty;

Jiri Zlathohlavek, Liberec, Czechoslovakia [21 App]. No. 829,380

[22] Filed June 2, 1969 [45] Patented Feb. 23, 1971 [73] Assignee Elitex-Zavody Textilniho Strojirenstvi Generalni Reditelstv, Liberec, Czechoslovakia [3 2] Priority May 30, 1968 [33] Czechoslovakia [54] WEFT SELECTING AND PRESENTING APPARATUS 7 Claims, 8 Drawing Figs.

[52] 11.8. CI. 139/122, 1 39/3 70 [51] Int. Cl. D03d 47/38 [50] Field ofSearch 139/122,1,

[56] References Cited UNITED STATES PATENTS 3,315,707 4/1967 Scheffel 139/122 3,347,283 10/1967 Bartosek et a1. 139/122 Primary Examiner-Henry S. Ja'hdon Attorney-Michael S. Striker ABSTRACT: Several differently colored weft threads are fed through brake means and tensioning means to a gripper shuttle in an order determined by a pattern. Only the selected thread is clamped by the brake means and tensioned by the tensioning means during insertion into the gripper shuttle, and after the pick of the shuttle, while untensioned and unclamped thread is fed to the gripper shuttle during weft insertion. The nonselected threads remain untensionedand are not with the movement of the woven fabric.

clamped, but slightlyTiakedand are guided in accordance PATENTEU FEB 2 3 Ian SHEET 2 BF 8 QQHC INVENTORS YLADIMIR sv -ry BY 5% i -Arena ATTORNEY PAIENTEnrsazsmn I 33565121 sum 3 UF 8 INVENTORS I v Vum IR SVATY B LMvuLAvEK ATTORNEY PATENTEU ma SHEET 5 BF 8 VINVENTORSQ! LADI "JIRI g m SVATY LATOHL-A VEK ATTORNEY PATENIEUFEMMQH 'sum 7 [IF 8 INVENTORS VLAVINR SVATY 11m LATOHLAVEK MMVKM ATTORNEY 1 u WEFT SELECTING AND PRESENTING APPARATUS BACKGROUND OF THE INVENTION incapable of obtaining the following objects of the invention:

It is one object of the invention to provide a selecting arrangement for different threads wherein the selected thread is not only guided in a correct position, but also at a desired tension.

Another object of the invention is to provide an arrangement in which the selected thread is released to permit rever-' sal of the gripper shuttle with a shuttle box, an operation which is necessary in certain gripper shuttle looms known under the trade name Novostav." Release of the selected threads for free movement is also necessary in other types of gripper looms before the thread is inserted into the gripper shuttle. In certain gripper shuttle looms, the weft thread is tensioned during the beat up by the reed when the weft inserting shuttle is picked after outward movement of the batten. It is therefore an object of the invention that the selected weft thread, after insertion into the gripper shuttle, is released so that formation of loops is prevented.

Another object of the invention is to feed the selected weft thread in unbraked condition, and preferably alonga substantiallystraight path to the picked gripper shuttle. ltis known that" breakages take place most frequently when the weft thread is braked, and that the brakedweftthread consumes partof the energy of the picked weft inserting member, which is usually of small weight.

Another object of the invention is to pull the thread back at a certain tension so that the part of the weft thread which followed the gr the shed and tensioned. I 1

Another object of the invention is to permit the nonselected threads to move with the fabric which is being woven while being taken off the thread supply bobbins. In certain patterns, a particuiar colored thread is not used again as a weft for a long time after its first insertion into a warp shed, so that such a thread must be taken off its supply bobbin as the workpiece is being woven and wound up.

"Another object of the invention is to use the tension of the selected thread for controlling a weft stop motion in-the case of breakage, while the nonselected threadshave no influence .on the weft stop motion. During the weaving of certain bands,

it is useless .to stop the machine when the top thread supply runs out, in the event that this thread isnot in a working position, and it is advantageous to stop the loom when the operator can feed a missing thread and fmishthe insertion of the same into the warp shed. In this manner, the machine is stopped at the warp shed corresponding to the color of the operative weft.

Another object of the invention isto check the correct tension of the inserted weft thread by a welt stop motion which stops the loom before the beat up operation of the reed in the event that due to a breakage no weft thread is located in the warp shed, and also in the event of insuflicient tension of the welt thread. The stopping of the loom before beat up by the reed has the advantage that the operator need not turn back the pattern control means, and can continue the weaving operation upon manual insertion of a weft thread into the warp shed where the thread was not supplied. I

The apparatus according to the prior'art are not capable of obtaining the above enumerated objects of the invention, and

have a higher breakage rate.

pper shuttle intothe warp shed is pulled out from bins without resistance by the gradually woven fabric, or by the weft inserting gripper shuttle. On the other hand, the threads are clamped between the gripper shuttle and the supply bobbins when the weft thread has to be pulled back after a weft insertion. Only the selected thread is tensioned, and also checked by a weft stop motion during the insertion into the gripper shuttle, as well as after the pick, so that breakage of a weft thread causes stopping of the loom at the moment at which the respective feeding element is active.

An apparatus according to the present invention comprises a unit for each different, or differently colored thread. Each unit includes a thread guiding element having a first guide eye and being movable between a normal position and inserting and guiding positions for inserting a weft thread into a gripper shuttle and for guiding the thread to the same, tensioning means having a second guide eye for the weft thread and being movable between tensioning and an untensioning position, brake means having a third guide eye for the thread and being movable between a normal position, for lightly breaking the thread, and a clamping position for fixedly clamping the thread, and thread supply means for supplying the thread to the brake means. The thread extends in the normal position of the feeding element through the first, second, and third guide eyes from a weft thread inserted by the gripper shuttle to the supply means.

Operating means are provided for moving the feeding element of the selected unit between the normal, inserting, and guiding positions, the tensioning means between the tensioning and untensioning positions, and the brake means between the normal and clamping positions in synchronism with the operations of the gripper shuttle. The arrangement is such that the tensioned clamped thread is inserted by the guiding element into the gripper shuttle, the untensioned and unclamped thread is fed to the gripper shuttle during weft insertion, and the thread is tensioned and clamped at the end of the weft insertion.

Each unit includes a coupling means which is operated by selector means to couple the tensioning element of the selected unit with a reciprocating operating member. Preferably, a selector means includes a selector electromagnet for operating the coupling means, and a selector switch In accordance with the invention, at a certain time, all weft V threads are unbraked so that they can be taken off supply boboperated by program control means,

such as a dobby mechanism.

In the preferred embodiment of the invention, the tensioning means includes a tensioning member mounted on the feeding element and biased by a spring. Two stationary stop means engage the tensioning member in two spaced positions of the feeding element while the brake is-in the normal position, and

release the tensioning member in intermediate positions, while the brake is operated to assume the clamping position.

The brake is preferably an electromagnetic brake controlled by a brake switch actuated by the reciprocating operating member at the proper moment when the tensioning member is released by the stop means, and can assume its tensioning position under the action of the respective tensioning spring.

The electric circuit of the apparatus comprises a transformer whose primary winding is connected with a voltage source, and whose secondary winding is connected with the electromagnetic brake means and the selector electromagnet. The brake switch is preferably controlled by a cam lever operated by the reciprocating operating member.

The spring biassed tensioning member is advantageously used for operating a stop motion switch when the thread breaks while the tensioning member is in the intermediate position spaced from the stop means, and can be freely turned by its tensioning spring.

A preferred method'of the invention comprises the steps of supplying a plurality of different threads to a gripper shuttle in accordance with a pattern, clamping a selected thread during insertion into the shuttle, and after the pick of the shuttle; tensioning the selected clamped thread; and unclamping and untensioning the thread during the pick of the gripper shuttle.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic front elevation, partially in section, illustrating the general arrangement of the apparatus of the invention;

FIG. 2 is a plan view, partially in section, illustrating a feeding unit, and including a diagrammatic showing of the electric circuit, and of the batten and gripper shuttle of a loom provided with the apparatus of the invention which is shown in a position of rest;

FIG. 3 is a schematic view corresponding to FIG. 2 but illustrating the operational position of the apparatus during the selection of a unit associated with a weft thread having a particular color;

FIG. 4 is a schematic view corresponding to FIGS. 2 and 3 and illustrating an operational position during weft insertion into the gripper shuttle;

FIG. 5 is a schematic view corresponding to FIGS. 2 to 4 and illustrating an operational position in which the thread is untensioned for reversal of the gripper shuttle;

FIG. 6 is a schematic view corresponding to FIGS. 2 to 5 and illustrating an operational position of the apparatus during the pick of the gripper shuttle;

FIG. 7 is a schematic view corresponding to FIGS. 2 to 6 and illustrating an operational position of the apparatus after completion of the pick of the gripper shuttle; and

FIG. 8 is a schematic view corresponding to FIGS. 2--7 and illustrating an operational position of the apparatus of which the stop motion is actuated due to a thread breakage occurring after the pick of the gripper shuttle.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to the general view of the feeding apparatus shown in FIG. 1, a stationary support 1, which is part of the machine frame 2, has a plurality of guide bores in which a plurality of guide means 3 is mounted, each guide means being movable in longitudinal direction between normal and actuated positions, as will be explained with reference to FIGS. 2- --8. Each guide means 3 includes a guiding element 19 with a guide eye 21 through which a thread passes which is supplied from supply bobbins 45. In the embodiment of FIG. 1, four guide means 3 are provided, which means that four threads of difi'erent color, or four diflerent threads, can be fed at each side of a loom which includes a batten or slay 59 on which a gripper shuttle 58 is mounted for reciprocating movement through the warp sheds of a fabric 59, as shown in FIG. 2.

An operating member 5 extends across the guide means 19 and is connected by a pivot 17 with a toggle lever which is connected by a joint 14 with a second toggle lever 16 mounted on a stationary pivot 18 on machine frame 2. A link 13 connects joint 14 with another pivot 12 at the end of a rocking cam follower lever 9 which carries a cam follower roller 8 and is turnable about a stationary pivot 10. A cam 6 is driven by drive shalt 7 and displaces cam follower means 8, 9 against the action of a spring 11 which is secured to support 1 and cam follower lever 9 and urges cam follower roller 8 against the periphery of cam 6.

During rotation of drive shaft 7, the operating means 6 to 17 effect a reciprocating motion of operating member 5, and when any of the guide means 19 is coupled with operating member 5 the respective feeding means 3 will also perform a reciprocating movement for inserting the respective thread into the gripper shuttle 58, while the other guide means 13 will remain in a normal position holding the respective threads in a position of readiness while the selected thread of the advanced feeding means is inserted by the gripper shuttle 57 into the next warp shed.

Referring now to FIG. 2, which illustrates the constructive details of one of the guide means and the selection of the guide means, each guide means 3 includes a thread guiding element 19 mounted in support or holder 1 for reciprocating movement between a normal position shown in FIG. 2, and an inserting and guiding position for inserting the thread into a gripper shuttle 58, and for guiding the thread 22 during the weft insertion movement of gripper shuttle 58, as shown in FIG. 6. In the nonnal inoperative position of each element 19, as shown in FIG. 2, an electric circuit including a transformer 65, which reduces the voltage from 220 volts to 24 volts, lines 64 and 66, and the coil 53 of an electromagnet brake 47 is interrupted by an open switch 42. A stop motion switch 67 on support 2 is closed so that a combined clutch and brake 68 is driven by a motor 69 which receives a polyphase current of 380 volts. As long as stop motion switch 67 is closed, the shafts of the loom are driven from clutch 68 and motor 69, including drive shaft 7 of the operating means, but when switch 67 is opened, the device 68 performs the function of a brake, and motor 69 is stopped.

A selector magnet 37 with a winding 38 connected to transformer 65 directly by a line 63, while a line 62 is connected with line 66 and transformer 65 by a selector switch 61. Each guide means 3 is associated with selector means including a selector magnet 37, 38 and a selector switch 61 so that each of the guiding elements 19 can be selected for inserting the respective thread 22 into the shuttle 58, While the remaining elements 19 remain in the inoperative normal position shown in FIG. 2.

Each element 19 has a projecting portion 20 cooperating with the operating member 5 which can be shifted between three positions I, II, III by the operating means 6 to 17. Each element carries a pivot 33 on which a double armed coupling pawl 34 is mounted whose coupling portion 35 cooperates with a coupling portion 39 of operating member 5. A spring 36 connects one arm of coupling pawl 34 with a nose at the end of an element 19, and urges coupling pawl 34 to the normal inoperative position shown in FIG. 2. When, upon closing of switch 61, the respective selector magnet 37, 38 is energized, coupling pawl 34 is attracted and turned to the position shown in FIG. 3 against the action of spring 36 so that the coupling portion 35 is located in the path of movement of the coupling portion 39 of operating member 5 during movement from position I to position II.

Each element 19 has a slot or cutout 25 in which a pin 26 is mounted for supporting a tensioning member 27 for angular movement between the position shown in FIG. 2, in which tensioning member 37 abuts a stop roller 24 on support I, and the position shown in FIG. 5 in which a nose of tensioning member 27 abuts a stop roller 23.

A tensioning spring 31 can be hooked into one of the holes 30 in tensioning member 27 and is also secured to a projecting nose 32 of the respective element 19 so that tensioning member 27 is urged to the position shown in FIG. 2, abutting stop 24.

Tensioning member 27 has a guide eye 28 at its free end through which thread 22 passes.

The brake 47 includes a supporting body 52 on which coil 53 is mounted, a fixed brake member 55, and a movable brake member 54 which is urged by a spring 57 against brake member 55, brake member 54 being mounted on a spindle 56 which can be adjusted. Threads of different colors or different texture are supplied from a set of supply bobbins 45 through guide 45, between brake members 55 and 54 to another guide 48, and from there through the respective guide eyes 28 of the tensioning arms 27. The threads 22 extend from guide eyes 28 over guides 49 through the guide eyes 21 of the guiding elements 19, and over guides 50 to the selvedge of the fabric 51 at the point 70 where a welt was last formed of the respective thread 22. Spring 57 is adjusted so that each thread 22 slides between brake members 55, 54 so that the respective thread 22 can be taken olf the cross wound bobbin 45 without causing yarn breakage or uncontrolled winding off of an undesirable length of thread 22 from supply bobbin 45. However, when coil 53 is energized under the control of brake switch 42, brake member 54 is strongly attracted and clamps its thread 22 so that nothing can be unwound from supply bobbins 45.

As mentioned above, the gripper shuttle $8 performs a reciprocating'rnovcment along the batten 59 which carries the reed 60. The batten 59 performs a rocking motion from a rear dead center, shown in FIG. 2, to a beat up position shown in FIG. 4.

The selection of one of the guide means 3 for inserting the respective thread having a specific color into the gripper shuttle 58, is effected by selector magnet 37, 38 when selector switch 61 is closed. Selector switch 6l'is operated in a known manner by a dobby mechanism, not shown, whose dobby levers, not shown, respectively control the selector switches 61 of the four selector magnets provided in the illustrated embodiment.

A cam lever 41 is mounted on a pivotal support 53 on a frame part, and has a free end connected by a spring 44 to another frame part. A cam follower roller 40 on the operating member 5 cooperates with cam lever 41 during movement of operating member from the position I to the positions II and III. As long as follower roller 40 is on therising portion 41' of cam lever 41, switch 42, which is connected by a link 42' with cam lever 41, remains open. When roller 40 engages the center portion of cam lever 41 in the position II of operating member 5, as shown in FIG. 4, brake switch 42 is closed. When roller 40 engages the slanted portion 42" of cam lever 41 in the position Ill of operating member 5, shown in FIG. 6, spring 44 pulls cam lever 41 to turn in clockwise direction so that brake switch 42 is open again.

As shown inFIGS. 2--7, tensioning'member 27 is normally spaced from stop motion switch 67. When thread 22 breaks, spring 31 pulls tensioning member 27 to a position in which its free end engages a projecting portion of stop motion switch 67 to open the same so that the circuit of clutch 68 is interrupted, and a spring places the device 68 in a braking position, stopping the loom and motor 69.

OPERATION Drive shaft 7 which is normally driven from motor 69 and clutch device 68,. rotates at half the number of revolutions of the main shaft of theloom so throw 6 causes a continuous rocking motion of lever 9-against the action of spring 11. The rocking motion is transmitted tooperating member 5 which is reciprocated from the position I shown in FIG. 2 to the position Ill shown in FIG. 6, and back in a return stroke to position I. Operating member 5 has guide bars 4 sliding in bores of support 1, as best seen in FIG. 1.

As long as the pattern control means of the machine, for example the dobby mechanism, not shown, does not actuateany of the selector switches 61, operating member 5 reciprocates between the positions I and III without any influence on the guiding elements 19, since the coupling portion 39 of operating member 5 is spaced from the coupling portion 35 of coupling pawl 34 on each feeding element 19. The weft thread 22, woven into the fabric 51, is guided over guide 50, guide eye 21, guide 49, guide eye 28 of tensioning member 27, guide 48, between members 55 and 54 of brake 47, guide 54, and is connected to the respective cross wound bobbin 45. In this condition of the apparatus, brake member 54 is lightly pressed against brake member 55 by a spring 57, and tensioning member 27 is turned by spring 31 in clockwise direction to the position of FIG. Z abutting the stop roller 24 on support 1. Since roller 40 of operating member 5 cooperates with the portion 41' of the cam lever 41, brake switch 42 is open. Selector switch 61 is also held open by a spring, not shown. The winding of selector magnet 37, and the winding 53 of nected by a clutch device 68 to the loorn shafts and through a transmission, not shown, having a ratio of 2 l, to drive shaft 7.

When the pattern control device, for example a lever of a dobby mechanism, not shown, closes a selected selector switch 61 since a thread having a particular color is required for the pattern, the circuit of lines 62, 63 and transformer 65 is closed, the respective selector magnet 37, 38 is energized, and coupling pawl lever 34, which serves as armature for selector magnet 37, 38 is attracted and turns in counterclockwise direction to the position shown in FIG. 3 in which its coupling portion 35 is located in the path of movement of coupling portion 39 of operating member 5, which is still in the position I so that switch 42 is open.

From this position, which is shown in FIG. 3, operating member 5 begins to move to position III and its coupling portion 39 engages coupling portion 35 so that the motion of operating member 5 is transmitted by the coupling means 39, 35, 34 to the respective guiding element 19 which moves together with operating member 5 to the position II, which is shown in FIG. 4.

Since roller 40 on operating member 5 now engages the center portion of cam lever 41, brake switch 42 is closed, and brake winding 53 is energized so that movable brake member 54 is strongly attracted and clamps thread 22 between brake member 55 and brake member 54. The displaced element 19 arrives in a position in which its guide eye 21 is adapted to insert thread 22 into the gripper of the gripper shuttle 58 which has approached the advancing element 19 since the batten 59 has moved from the retracted position shown in FIG. 3 to the beat up position shown in FIG. 4 in which reed 60 has beaten the last inserted weft into the fell of fabric 51. Since a differently colored weft than weft 22 was used for the last weft, thread 22 extends from another weft toward guide 50.

In the position of FIG. 4, in which thread 22 is clamped firmly between brake members 55 and 54, a limited length of thread 22 extends between selvedge point 70 where weft 22 enters the fabric 51, and the brake 47. In the clamping position of brake 47, no additional thread can be supplied from the respective supply bobbin 45. The advancing motion of feeding element 19, which has freed tensioning member from stop 24, permits spring 31 to turn tensioning member 27 in clockwise direction until the available length of thread 22 is tensioned only due to the action of spring 31, and a tensioned loop is formed between guides 48 and 49 and guide eye 28 of tensioning member 27.

Thread 22 is inserted into the gripper or gripper shuttle 58, and batten 59 begins to return to its rear dead center position. Operating member 5 moves from position II shown in FIG. 4 further toward position III, taking along coupling pawl 34 and feeding element 19 until the nose 29 of tensioning member 27 abuts stop 23, as shown in FIG. 5, which causes a turning movement of tensioning member 27 about pivot 26 against the action of spring 31 whereby the tension applied to the length of thread between selvedge, point 70 and brake means 47 is reduced. During this movement, guide eye 21 and the free end of feeding element 19 follow batten 49 during its rearward movement and remain in the proximity of gripper shuttle 58. After the thread 22 has been inserted into gripper shuttle 58, it is cut off by cutting means, not shown, in the region of guide 50 so that a thread end 22" remains connected with the previously inserted weft and the point 70.

The loom is of the well known type in which the gripper shuttle 58 enters a turnable'shuttle box, not shown, and is turned 180 before it is again picked in the opposite direction to travel from the right to the left, as viewed in the drawing, for inserting thread 22 as a weft in the newly opened warp shed. The release of thread 22 by the displaced tensioning member 27 in the position of FIG. 5 permits the turning of gripper shuttle 58 an angle of 180 without increasing the tension in the limited length of thread 22 between the shuttle and brake means 47. During this operation, electromagnetic brake 47 are not energized. Motor 69 is operative and conmeans 37 and 47 remain energized.

In the following position of FIG. 6, operating member has moved to position III. During this motion, guiding element 19 has been further moved while gripper 58 has been picked through the warp shed. The engagement of nose 29 with stop 25 has caused turning of tensioning member 27 from the position of FIG. 5 to the position of FIG. 6, and since roller 40 is no longer located on the center portion of cam lever 41, switch 42 is opened by the action of spring 44 so that brake 47 is deenergized, and brake members 55, 57 no longer clamp thread 22, permitting the travelling shuttle 58 to pull thread 22 through guide eyes 21, 28, 48, 46 from supply bobbin 45 and between the brake members 55, 57 which only lightly control the tension of thread 22 due to the action of spring 57. It will be noted that in the position of tensioning member shown in FIG. 6, all guide eyes are substantially aligned so that little resistance is encountered by shuttle 58 drawing thread 22 through the warp shed.

When gripper shuttle 58 has travelled through the shed and arrives on the other side of the fabric, operating member 5 begins to return from its end position III to the position II in which roller 40 again closes brake switch 42. Winding 53 of brake 47 is energized, and brake members 54, 5S clamp thread 22 again, as shown in FIG. 7. Thread 22 can no longer be taken ed the supply bobbin 45. At the same time, tensioning member 27 is fully released by stop 23 and is pulled by spring 31 to turn in clockwise direction for again tensioning thread 22 together with the thread portion inserted into the warp shed by shuttle 58. In this manner, the inserted weft thread is slightly tensioned and held in the warp shed in a straight position.

At the beginning of the motion of operating member 5 from position III to position 11, coupling portion 39 separates from coupling portion 35 so that spring 36 turns coupling pawl lever 34 to the position of FIG. 7 in which the coupling between operating member 5 and feeding element 19 is temporarily interrupted. Thereupon, operating member 5 in the position II engages a shoulder formed on feeding element 19 by the projecting portion 20 so that feeding element 19 is again coupled with operating member 5 for movement toward position I. When operating member 5 is again in the initial position I, all parts assume the position shown in FIG. 2, and the cycle of operations can be repeated if the motor 69 continues to operate. During the following operation, another guide means 3, including guiding element 19, coupling pawl 34, spring 31, and tensioning member 27 may be selected by selector spring 61 and selector magnet 37, 38 under the control of the selecting dobby mechanism, not shown. The nonselected guide means 3 remain in the position shown in FIG. 2 in which the moving fabric 51 draws thread 22 from respective supply bobbins 45.

In the event that the thread 22 breaks at the moment in which feeding element 19 moves in either direction, while operating member 5 reciprocates between the positions I and Ill, and back, and while brake 47' is energized and clamps the thread, as shown in FIG. 8, the tension exerted by spring 31 on tensioning member 27 turns tensioning member 27 out of the position shown in FIG. 4 to the position of FIG. 8 in which its end engages a projecting arm of stop motion switch 67 and opens the same whereby motor 69 is disconnected and braked by brake 68 so that the loom is stopped. This may occur at the time of drawing back thread 22, as well as at the time of feeding a new weft thread, provided that the nose 29 of tensioning member 27 does not engage stop 23 whereby the loom is stopped always at a certain working phase of the loom, namely at the moment in which tensioning member 27 is neither engaged by stop 23 nor by stop 24, and when tensioning member 27 is pulled by spring 31 to a position tensioning the loop of thread 22 between guides 48, 49 and guide eye 28 on tensioning member 27. Stopping of the loom upon yarn breakage will consequently take place only in the positions shown in FIGS. 4, 7 and 8.

0f the several, difi'erent, or differently colored threads which are available for forming wefts, only the thread which is picked with the shuttle is tensioned and checked by the weft stop motion by opening of stop motion switch 67 by the tensioning member 27 and the same is spaced from stops 23 and 24 in the positions of FIGS. 4 or 7. The inactive weft threads are situated in the position shown in FIG. 2 in which tensioning members 27 abut stop 24 so that even if the respective thread 22 breaks, the respective springs 31 cannot operate respective tensioning members 27 to actuate stop motion switch 67.

As can be seen in FIG. 2, all feeding elements which are not active, will permit the taking off of threads from the respective bobbins 45 as fabric 51 is gradually wound up. Since brake members 55 and 54 are only slightly tensioned by spring 26, and the brake means 47 of the inactive feeding means 3 are not energized, the gradually advancing rolled up fabric 51 can draw a small length of inactive threads from supply bobbins 45. This arrangement is particularly advantageous for weaving top band fabrics, when the length of the thread 22 between guide 50 and point 70 where the thread enters the fabric is great due to the fact that one of the threads has not been used for a number of weft insertions. Since the wound up fabric 51 can easily pull threads 22 from the supply bobbins 45 of the inactive feeding means 3, the selvedges of fabric 51 are not subjected to tension.

It will be understood that each of the elements described above, or two or more together, may also fine a useful application in other types of thread guiding apparatus for gripper shuttles differing from the types described above.

While the invention has been illustrated and described as embodied in an apparatus for selecting a thread of a plurality of different colored threads for insertion into a warp shed by a gripper shuttle, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

We claim:

1. Weft selecting and presenting apparatus for a gripper shuttle, comprising, in combination, a unit including a thread guiding element having a first guide portion and being movable between a normal position and inserting and guiding positions for inserting a weft thread into said gripper shuttle and for guiding the thread to the same, tensioning means including a tensioning member having a second guide portion for said thread and being pivotably mounted on said guiding element movable between a tensioning and an untensioning position, and a tensioning spring connecting said tensioning member with said thread guiding element; comprising means limiting the movement of said tensioning member in two spaced positions of said thread guiding element, and releasing said tensioning member in intermediate positions of said guiding element; brake means having a third guide portion for said thread and being movable between a normal position, and a clamping position for clamping said thread, and thread supply means for supplying said thread to said brake means, said thread extending in said normal position through said first, second, and third guide portions from a weft thread inserted by said gripper shuttle to said supply means, said brake means including an electromagnetic brake and a brake switch for moving said electromagnetic brake to said clamping position; and operating means for moving said feeding element between said normal, inserting and guiding positions, said tensioning means between said tensioning and untensioning positions, and said brake means between said normal and clamping positions in synchronism with the operations of said gripper shuttle so that tensioned clamped thread is inserted by said guiding element into the gripper shuttle, so that untensioned unclamped thread is fed to said gripper shuttle during weft insertion, and so that the thread is tensioned and clamped at the end of a weft insertion, said operating means including a reciprocable operating member for reciprocating said thread guiding element with said tensioning member and said tensioning spring, and engaging and actuating said brake switch while said tensioning member is in said intermediate positions so that said brake is placed in said clamping position and said tensioning spring moves said tensioning member to said tensioning position while said thread is clamped.

2. Apparatus as claimed in claim 1 comprising a plurality of said feedingfunits, each unitinciuding a thread guiding element, tensioning means, brake means, thread supply means, and coupling means for coupling a selected one of said units with said operating means; and selector means for selecting and actuating one of said coupling means so that said feeding element of the selected unit is reciprocated by said operating means between said normal andinserting'and feeding positions for inserting the respective thread into said gripper shuttle; and wherein said thread supply means of different units supply different threads to saidfeeding elements, respectively.

3. Apparatus as claimed in claim 2 wherein each tensioning means includes a tensioning member having said second guide portion and being pivotally mounted on said thread guiding element, and a tensioning spring connecting said tensioning member with said element; wherein said operating means include a reciprocable operatin member coupled by said coupling means with said elem nt of the selected unit for reciprocating the respective el ment with said tensioning member and said tensioning spring; and comprising two stop means for engaging said tensioning-member in two spaced positions of said element, and releasing said tensioning memberin intermediate positions.

4. Apparatus as claimed in claim 3 and comprising a cam lever connected with said brake switch for operating the same, and being engaged and angularly displaced by said operating member, said cam lever having a center portion and two slanted end portions, and being pivotally mounted at one end, and a spring connected to the other end of said cam lever for urging the same against said operating member, said brake switch being operated only when said operating member cooperates with said central portion of said cam lever.

5. Apparatus as claimed in claim 4 wherein said coupling means of each feeding unit includes a coupling pawl mounted on the respective feeding element for pivotal movement between an inoperative position and a coupling position coupled with said operating member, and a spring bisssing said coupling pawl toward said inoperative position; and wherein said selector means include a selector electromagnet and a program controlled selector switch in the circuit of said selector electromagnet so that when anyone of said selector switches is operated in accordance with a program, the selector electromagnet of the respective unit is energized and operates said coupling pawl to move to said coupling position so that reciprocation of said operating member in one direction effects movement of said thread guiding element toward said inserting and guiding positions, said element having a projection engaged by said operating member during return movement of the same so that said element is moved to said normal position.

6. Apparatus as claimed in claim 3 wherein said electromagnetic brake means includes a stationary brake member and a movable brake member, and a spring biassing said movable brake member toward said stationary brake member in said normal position so that the thread between said brake members is braked, and wherein said electromagnetic brake means, when energized upon actuation of said brake switch,

attracts said movable brake member to abut said stationary brake member with a great force for clamping the thread between said brake members.

7. Apparatus as claimed in claim 3 wherein said operating means include a drive shaft; comprising a motor for driving said drive shaft, and means for stopping said motor including a stop motion switch; and wherein said tensioning member is moved by said tensioning spring to a position actuating said stop motion switch when the thread breaks while said brake means is in said clamping position, and said tensioning member is in said intermediate position spaced from said stop means.

Claims (7)

1. Weft selecting and presenting apParatus for a gripper shuttle, comprising, in combination, a unit including a threadguiding element having a first guide portion and being movable between a normal position and inserting and guiding positions for inserting a weft thread into said gripper shuttle and for guiding the thread to the same, tensioning means including a tensioning member having a second guide portion for said thread and being pivotably mounted on said guiding element movable between a tensioning and an untensioning position, and a tensioning spring connecting said tensioning member with said thread guiding element; comprising means limiting the movement of said tensioning member in two spaced positions of said thread guiding element, and releasing said tensioning member in intermediate positions of said guiding element; brake means having a third guide portion for said thread and being movable between a normal position, and a clamping position for clamping said thread, and thread supply means for supplying said thread to said brake means, said thread extending in said normal position through said first, second, and third guide portions from a weft thread inserted by said gripper shuttle to said supply means, said brake means including an electromagnetic brake and a brake switch for moving said electromagnetic brake to said clamping position; and operating means for moving said feeding element between said normal, inserting and guiding positions, said tensioning means between said tensioning and untensioning positions, and said brake means between said normal and clamping positions in synchronism with the operations of said gripper shuttle so that tensioned clamped thread is inserted by said guiding element into the gripper shuttle, so that untensioned unclamped thread is fed to said gripper shuttle during weft insertion, and so that the thread is tensioned and clamped at the end of a weft insertion, said operating means including a reciprocable operating member for reciprocating said thread guiding element with said tensioning member and said tensioning spring, and engaging and actuating said brake switch while said tensioning member is in said intermediate positions so that said brake is placed in said clamping position and said tensioning spring moves said tensioning member to said tensioning position while said thread is clamped.

2. Apparatus as claimed in claim 1 comprising a plurality of said feeding units, each unit including a thread guiding element, tensioning means, brake means, thread supply means, and coupling means for coupling a selected one of said units with said operating means; and selector means for selecting and actuating one of said coupling means so that said feeding element of the selected unit is reciprocated by said operating means between said normal and inserting and feeding positions for inserting the respective thread into said gripper shuttle; and wherein said thread supply means of different units supply different threads to said feeding elements, respectively.

3. Apparatus as claimed in claim 2 wherein each tensioning means includes a tensioning member having said second guide portion and being pivotally mounted on said thread guiding element, and a tensioning spring connecting said tensioning member with said element; wherein said operating means include a reciprocable operating member coupled by said coupling means with said element of the selected unit for reciprocating the respective element with said tensioning member and said tensioning spring; and comprising two stop means for engaging said tensioning member in two spaced positions of said element, and releasing said tensioning member in intermediate positions.

4. Apparatus as claimed in claim 3 and comprising a cam lever connected with said brake switch for operating the same, and being engaged and angularly displaced by said operating member, said cam lever having a center portion and two slanted end portions, and being pivotally mounted at one end, and a spring connected to the other end of Said cam lever for urging the same against said operating member, said brake switch being operated only when said operating member cooperates with said central portion of said cam lever.

5. Apparatus as claimed in claim 4 wherein said coupling means of each feeding unit includes a coupling pawl mounted on the respective feeding element for pivotal movement between an inoperative position and a coupling position coupled with said operating member, and a spring biassing said coupling pawl toward said inoperative position; and wherein said selector means include a selector electromagnet and a program controlled selector switch in the circuit of said selector electromagnet so that when anyone of said selector switches is operated in accordance with a program, the selector electromagnet of the respective unit is energized and operates said coupling pawl to move to said coupling position so that reciprocation of said operating member in one direction effects movement of said thread guiding element toward said inserting and guiding positions, said element having a projection engaged by said operating member during return movement of the same so that said element is moved to said normal position.

6. Apparatus as claimed in claim 3 wherein said electromagnetic brake means includes a stationary brake member and a movable brake member, and a spring biassing said movable brake member toward said stationary brake member in said normal position so that the thread between said brake members is braked, and wherein said electromagnetic brake means, when energized upon actuation of said brake switch, attracts said movable brake member to abut said stationary brake member with a great force for clamping the thread between said brake members.

7. Apparatus as claimed in claim 3 wherein said operating means include a drive shaft; comprising a motor for driving said drive shaft, and means for stopping said motor including a stop motion switch; and wherein said tensioning member is moved by said tensioning spring to a position actuating said stop motion switch when the thread breaks while said brake means is in said clamping position, and said tensioning member is in said intermediate position spaced from said stop means.

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