GB1570426A - Method and apparatus for controlling weft threads - Google Patents

Abstract

For the reliable alternating insertion of two different weft threads into the shed, at least during the time of insertion of the first weft thread the end of the second weft thread, which has been inserted into the shed before the first weft thread, is held and tensioned. After the end of insertion of the first weft thread, the held end of the second weft thread is cut off.

Description

(54) A METHOD AND APPARATUS FOR CONTROLLING WEFT THREADS (71) We, VTZKUMNY A VTVOJOVT ÚSTAV ZAVODQ VSEOBECNÉHO STRO JfRENSTVf. of 76 Gottwaldova, Brno, Czechoslovakia, a corporate body organised and existing under the laws of Czechoslovakia, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a method and apparatus for controlling weft threads in jet weaving looms provided with a weft mixing device.

n jet weaving looms, the front end of the weft thread to be inserted must be drawn back as near as possible to the outlet opening of the nozzle. Upon this drawing back, the weft must be firmly clamped, however this clamping must be temporarily released during weft insertion. An important condition of weaving with weft mixing in jet weaving looms is, that the weft not being inserted is held and tensioned in a controlled manner so long as the insertion of the weft just to be inserted is not finished. Otherwise, the danger of negative effect by the weft thread not to be inserted upon the weft thread to be inserted exists, this might cause a fault in the fabric.

In jet weaving looms, which are not provided with mixing devices for the weft threads, the device for controlling weft thread during one operation cycle of the loom must perform the following series of operative steps: - weft insertion, i.e. opening and closing of weft clamps; - back drawing of the weft from the shed, i.e. tensioning of the inserted weft; - cutting the weft; - back drawing of the cut weft end into the inserting elements, e.g. the nozzle.

Various methods of controlling two wefts have been proposed, in which all necessary operations as mentioned above were not considered due to their intricacy. Furthermore, the just inserted weft was not tensioned and retained minimally until the moment of finishing the weft insertion of the next weft thread being inserted. Those devices did not provide conditions permitting a reliable alternating insertion of two weft threads.

A weft controller is known, which includes a stationary shaft, an annular segment mounted for oscillation on the shaft, a cam, a transmission mechanism for oscillating the annular segment, a first and second long arm mounted swingably on the shaft and a resilient means mounted on both long arms in such a manner as to hold them in a V-shape position on the shaft, stop means mounted on the annular segment in such manner as to cause the long arms to swing on the stationary shaft upon oscillation of the annular segment. It is obvious, that the whole device controlled by stops, operates at a high noise level, and that the impacts thus caused necessarily reduce the lifetime of the components thereof.

These disadvantages and shortcomings are overcome to a considerable extend by the method and apparatus according to the present invention.

Accordingly in one aspect the present invention provides a method of controlling weft threads in jet looms which operate with alternation of insertion of different first and second weft threads, which method comprises opening a first shed of the loom, inserting the first weft thread into the first shed, beating up the inserted first weft thread, closing the first shed, retaining the inserted first web thread in uncut condition under tension, opening a second, subsequent shed, inserting the second weft thread into the second shed, beating up the inserted second weft thread, retaining the inserted second weft thread under tension, and cut ting off the first weft thread.

In another aspect the present invention provides an apparatus for controlling weft threads in jet looms which operate with alternation of insertion of measured lengths of different first and second weft threads, the apparatus including a weft cutting mechanism, comprising a clamp for each weft thread, a pair of inserting nozzles mounted so that each nozzle alternately moves into an inserting and a non-inserting position, directing means with guides for each weft thread, the inserting nozzles and the directing means being arranged for swinging about a common axis, the inserting nozzles and directing means being disposed between the weft cutting mechanism and the clamp and weft thread retainers arranged between the respective nozzle and weft thread directing means for retaining the respective weft thread when its nozzle is in a non-inserting position.

A further feature of the present invention is the controlling of the hook control by an independent cam, continuous motion of the device without impacts and thus a more suitable treatment of the textile fibre, an independent motion of the hook and the clamps and a longer lifetime of the components.

The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a side view of the device for changing nozzles; Figure 2 is a front view of the device for changing nozzles; Figure 3 is a side view of the device of the weft trap; Figure 4 is a side view of the device of the weft clamp; and Figure 5 is a graphical representation of the operation cycles of the weft control device according to the present invention.

The weft control device is located between the weft magazine 40 on the one hand and picking the device, the reed and the inserting channel on the other hand.

On the loom frame 30 there is fastened a housing 32 by means of screws 31. Within the housing 32 are mounted parts of the weft controller. A main shaft 36 and a cam shaft 37 parallel thereto are journalled in the housing, the cam shaft being driven from the main shaft by a gear transmission, the cam shaft 37 rotating at half the speed of the main shaft 36. A cam 34 for moving weft inserting nozzles 72, 73 is fixed to the cam shaft 37. Motion is transmitted from the cam 34 to the nozzles 72, 73 by means of cam follower and a lifter rollers 43, 44 which are mounted on the ends of the respective arms of the two-armed lifter 35.

The lifter 35 is fixedly mounted on a counter-shaft 45 disposed parallel to the main shaft 36 and the cam shaft 37, the lifter 35 oscillating the counter shaft 45 as the cam shaft 37 rotates. A lever 52 is connected to the countershaft 45 by a clamping connection 39, the outer end of lever 52 being connected to the outer end of a lever 54 by a tie rod or link 53 which is pivotally connected to the levers. The lever 54 is fixedly connected to an output shaft 60, disposed parallel to shafts 36, 37 and 45, by a clamping connection 55. The output shaft 60 oscillates in synchronism with oscillation of the countershaft 45.

An L-shaped stand 62 is fastened on the housing 32 displaceably in the direction of the weaving plane 50 by screws 61. A body 64 of the output shaft 60 is fastened to the L-shaped stand 62 displaceably in a plane perpendicular to the weaving plane 50 by means of screws 63. A weft directing means 69 provided with an upper weft eyelet and a lower weft eyelet 74, 75 is firmly fasted to the output shaft 60 (Figure 2). Also a nozzle holder 70 is attached to the shaft 60 by a clamping connection tightened by a screw 71.

Nozzles 72, 73 are disposed on a circle which is coaxial of the axis A of the output shaft 60.

The eyelets 74, 75 of the weft directing means 69 are disposed in such manner, that their centres lie on the same circle as nozzles 72, 73. The clamping connection 71 between the nozzle holder 70 and the shaft 60 permits the nozzles holder to be adjusted about the shaft 60 to permit the nozzles 72, 73 to be aligned with respect to eyelets 74, 75. The output shaft 60 is so disposed that its axis A coincides with the fell of the loom.

The previously described adjustments of body 64 with respect to stand 62 and of stand 62 with respect to the housing 32 permits the output shaft 60 to be disposed as described.

The nozzles 72, 73 are fastened to the holder 70, e.g. by means of a spectableshaped sleeve, which makes it possible to easily change the nozzle upon a change in the weft material being used.

In Figure 1, the nozzle 72 is shown in the weft inserting position B and the nozzle 73 in its lower non-inserting position C. The points A, B and C preferably form an equilateral triangle. With an angle of oscillation of the output shaft 60 of 60 , and with the axis A of the shaft 60 congruent with the binding point and an angle of swinging of the motion of the nozzles 72, 73 is such that when one nozzle is moved from the weft inserting position to its non-inserting position the weft is drawn back from the shed and the weft after insertion is tensioned.

Furthermore, drawing back of the cut weft yarn end into the nozzle is achieved.

On the cam shaft 37 are mounted two cams 80, 81 which are fastened to the shaft by means of screws 82, which permit the cams to be adjusted around the axis of shaft 37 so that the moment of retaining the weft can be adjusted. In order to permit adjustment of the time of retaining of the weft, cams 80, 81 are divided and completed by parts 80', 81'. By changing the angle of overlap of cam parts 80, 80' on the one hand, and 81, 81' on the other adjustment of the retainment, time is achieved. The cam parts 80', 81' can be fastened to the cams 80, 81 e.g. by means of screws 83.

On the countershaft 45, there are pivotally mounted without the possibility of sideways shifting two two-arm levers 85, 86.

On each arm of each lever 85, 86 there are mounted cam following rollers 87, 88 which are in contact with the cams 80, 81 of the retainer mechanism. The length of the other arms of the levers 85, 86 can be adjusted by providing each such arm with a separate extension 90, 91 which are connected to the upper lever arms of levers 85, 86 by slot and screw connections 89, which permit the effective lengths of such upper arms of levers 85, 86 to be adjusted.

Tie rods or links 92, 93 are pivotally connected to the upper ends of lever arms 90 and 91, respectively, the upper ends of links 92 and 93 being pivotally connected to weft retainers 97 and 98. Retainers 97, 98 are mounted on shaft 60 for free rotation thereto. The upper retainer 97 is a two-arm lever, the lower arm of which is pivotally connected to the link 92. The lower retainer 98 is also a two-arm lever, the lower arm of which is pivotally connected to the upper end of link 93. A spring 102 disposed between a spring bracket 105 and the lower arm of the upper retainer 97 retains the roller 87 in firm contact with the cam 80, 80'.

A similar coil tension spring 101 is disposed between the spring bracket 105 and the upper arm of the lower retainer to maintain the cam following roller 88 in firm engagement with its cam 81, 81 '.

The upper arm of the upper weft retainer 97 is formed by two introducing shields 97a, 97b. Between shields 97a and 97b there is rotatably mounted a weft retaining hook 100a. The hook arm of the lower retainer 98 likewise carries two shields designated 98a and 98b, there being a rotatable weft retaining hook 100b mounted between the shields 98a and 98b. The retaining hook 100a is pivotally connected to one end of a link 103a, the other end of such link being pivotally connected to a bracket 1 04a which is fixedly mounted upon the frame of the apparatus. The retaining hook 1 00b on the lower retainer 98 is pivotally connected to one end of a link 103b by means of joint 171, the other end of such link being pivotally connected to a bracket 104b connected by means of a joint 172b to the member 64.

The retaining hook 1 00a which is pivotally mounted on the upper retainer 97, is pivotally mounted to one end of a link 103a by means of joint 171a, the other end of such link being pivotally mounted to a bracket 104a by means of a joint 172a mounted upon the body 64. The brackets 1 04a and 104b are mounted on body 64 for adjustment about the axis of the shaft 60. It will be apparent that the retaining hooks are swung about their mounting pivots 170a, 170b on the respective weft retainers 97, 98 as such retainers are oscillated around shaft 60.

By changing the effective length of the upper arms of the levers 85, 86, the swinging motion of the lower and upper weft retainers 97, 98 is changed. By changing the length of the adjustable tie rods or links 92, 93 the position of the weft retainers 97, 98 is changed.

The upper weft retainer 97, the retaining hook 100a and the tie rod 103a form together a four-joint mechanism, of which the pitman is the closing hook 100a and the balance beams the upper retainer 97 and the tie rod 103a.

The lower retainer 98, the retaining hook 100b and the tie rod 103b form a four-joint mechanism, of which the pitman is the closing hook 100b and the balance beams the lower retainer 98 and the tie rod 1 03b.

The balance beams of the mechanisms of the retainers 97, 98 are mounted on the output shaft 60, the other balance beams, that is, the tie links 103a, 103b are mounted on the brackets 104a, 104b on the circumference of the circular part of the body 64 which journals the output shaft 60. The circular part or body 64 is coaxial with the output shaft 60.

On the common cam shaft 37 (Figures 3, 4) are adjustably mounted two cams 120, 121, of the weft clamping mechanism, by means of screws 122. This permits the moment of clamping of the weft to be adjusted. In order to provide for an adjustment of the duration of the clamping of the weft, cams 120, 121 are made in two parts 120', 121', the parts 120', 121' being angularly adjustable with respect to the cams 120, 121, the parts of each cam being fastened together by screws 123 threaded into one part of the cam and extending through arcuate slots in the other part thereof. By changing the degree of overlapping of the parts of the respective cams, the required duration of weft clamping is attained.

On the countershaft 45 are pivotally mounted levers 124, 125 without the possibility of sideways shifting. On one arm of each lever 124, 125 there is mounted rollers 126, 127 which are in permanent contact with the cams 120, 121. The other arm of each of levers 124, 125 transmits motion from the cam follower via links 128, 129 to the weft clamps 130, 131 which are mounted on the output shaft 60 for free rotation with respect thereto. The weft clamps 130, 131 are formed as respective assemblies, each operated by its respective mechanism. Both clamp assemblies ar mounted on shaft 60.

The upper clamp 130 has a lever, the upper end of which is connected to one end of a spring 133, the other end of which is connected to a bracket 134 which is fastened to the L-shaped body 62. The spring 132 ensures constant engagement between roller 126 and the cam 120.

One end of a coil spring 132 is connected to the lever of the lower clamp 131, the other end thereof being fastened on the bracket 134. The spring 132 ensures constant engagement between the roller 127 and the clamp operating cam 121.

To the body 64 which journals the shaft 60 is fastened a bracket 135 of a stationary clamp (Figure 2), elements 137a, 137b and 138a, 138b of stationary clamps 137, 138 being fastened to the bracket 135. Elements 137b, 138b are advantageously made of such resilient material as rubber, and elements 137a, 138a are made in the form of metal plates.

On the carrying parts 130', 131' of the movable clamps 130, 131 are fastened the movable clamps 140, 141. The elements 140b, 141b of the movable clamps are advantageously made of resilient material such as rubber and elements 140a, 141a are made in the form of metal plates. The fastening of the clamps 140, 141 to the carrying parts 130', 131' is advantageously formed as a demountable clamping connection. On the bracket 135 of the stationary clamp are fixed two stationary eyelets 139a, 139b, the axes of which are directed parallel to the axis of the weft inserting nozzle 72 or 73, which is disposed in the inserting position B.

The clamps 130, 131 are advantageously made in such manner, that they are constituted by carrying parts 130, 131' and bodies 130", 131" which are mutually connected by clamping connection (not shown) which is demountable. Thus, the relative position of parts 130' and 131" can be adjusted, so that the pressing of resilient elastic elements 137b, 138b and 140b, 141b at the moment of clamping a weft by metal plates 137a, 140a or 139a, 141a may be changed.

When the device is used in a weaving loom in which the weft is guided through the shed e.g. by means of an inserting channel and the position of the inserting elements, e.g. nozzles 72, 73 depends in the inserting position upon the axis of the said inserting channel, the centre of the nozzle 72 or 73 is adjusted into the required inserting position by means of adjusting the clamping connection which fastens the lever 54 to shaft 60.

Such adjustment is made possible because the upper retainer 97, the lower retainer 98, the upper weft clamp 130, the lower weft clamp 131 are adjustably mounted on the output shaft 60. At the same time, it is necessary to adjust the position of the weft cutting point relative to the axis of output shaft 60.

The above-described apparatus according to the present invention operates as follows: Two different weft threads hereinafter called wefts I, II, are delivered from magazine 40 for measured weft lengths and are guided in two stationary eyelets 1 39a, 1 39b of weft clamps, weft I for example passing through clamp 130 and weft II passing through clamp 131. The wefts are further guided in guides 74, 75 of the directing means 69 and inserting elements, here made in the form of nozzles 72, 73.

Before starting the machine, it is necessary to clamp the wefts I, II by both pairs of the clamping elements 137a, 140a and 138a, 141a. This condition is maintained except when one of the nozzles 72, 73 is in the inserting position B of the weaving loom. Thus, for example, weft II is further guided by the lower retainer 98 into the space of the cutting point of the weft cutting device. The weft I is guided in turn to the cutting point by the upper retainer 97. This may be achieved in several ways, e.g. by a control button for the machine cycle, or by the unravelling device of the weaving loom.

If the said operations cannot be performed in the weaving loom, this is achieved by manual control of the cycle or by manual directing of the weft thread.

Now it is possible to start the weaving loom. The initial position (Figure 5) is denoted 150. In Figure 5, the various parts of the loom are assumed to be in the positions shown in Figures 1, 2, 3 and 4. As noted, the upper branch or weft set is called weft I. Weft I is operated upon by the upper nozzle 72, the upper clamp 130 and the upper retainer 97. Also as noted the lower branch or weft set is called weft II. Weft II is operated upon by the lower nozzle 73, the lower clamp 131 and the lower retainer 98.

The operation shown in Figure 5 proceeds in the direction from left to right, the horizontal coordinate representing the degrees of turning of the cam shaft 37 from, as assumed, zero position.

Position 150 This position is the inserting position of the weft I. The weft clamp 13 does not clamp the weft I, the retaining hook 1 00a of the upper retainer 97 does not hold weft 1.

The weft clamp 131 clamps the weft II, the closing hook of the lower retainer 98 holds the weft II which is not cut, but which is held by the retaining thumb of the cutting device (not shown) at the cutting point A. The apparatus remains in that position, during the whole time of insertion of weft I, until position 151 is reached.

Position 151 This position represents the termination of insertion of the weft I. The weft clamp 130 clamps the weft I, otherwise the operation in this position is the same as in position 150.

Position 151-152 WEFT I Weft I, which is clamped by the weft clamp 130 is tensioned by movement of the nozzle 72 from the inserting position into its non-inserting position and is drawn back from the shed, the drawing back of the weft to the nozzle being effected by means of a coincident movement of the nozzle 72 and the unit 69. Nozzle 72 and unit 69 move synchronously and in a common plane. The length of weft I drawn from the shed can be changed by the initial adjustment of the position of the retainer 97, which is in the path of the weft I which is tensioned and drawn from the shed, m the-space between the directing means 69 and the nozzle 72, thus forming an adjustable bend or loop P1 of weft 1 about the grooves in the introducing shields of the retainers 97 and 98.Means 69 and nozzle 72 move together because both are fixedly secured to shaft 60. At the moment, the retainer 97 is in motion, that is, it swings out in the direction of movement of the change of the nozzles 72 and 73. The swinging motion of the retainers 97, 98 causes the grooves in the introducing shields to be closed and determines by the hook 100a, 100b, the extent of the swinging motion of the retainer 97, thus determining the length of drawing weft I into the nozzle 72.

Special attention is to be paid to the bend or loop Pi, formed in weft I. This is actually a loop formed in the weft thread with an adjustable length. The properties of the four-joint mechanism consisting of the upper retainer 97, the closing hook 100a and the tie rod 103a mounted on the bracket 1 04a make possible the changing of the length of the tool.

As noted above, drawing back the weft to the nozzle is not effected by the retainer 97, but by means of coincident movement of the nozzle and the unit 69. Both these elements move synchronously and in a common plane. After the loosening of the retaining means formed by the retainer 97 and the hook 100a (or by the retainer 98 and the hook 100b), just in the moment of the beginning of insertion, the loop or weft is loosened, thus securing a perfect course of insertion.

Weft II Nozzle 73 is moved from the non inserting position into the inserting position.

At the moment of tensioning the weft II, which is caused by the motion of the nozzle 73, weft II is cut upon being held by the retaining hook 100b of the retainer 98.

Further, weft II is clamped by the clamp 131. The movement of nozzle 73 from the non-inserting position into the inserting position causes the end of the cut weft II to be drawn back into the nozzle 73. As the length of the cut end of the weft II is the same as the path of movement of the nozzles 72 and 73 (see the equilateral triangle A, B, C, described above) the whole length of the cut end of the weft II will be drawn into the nozzle. Actually, this length is also adjustable, as explained below.

Meanwhile, the reed moves into the beat-up position and the shed is closed. The movement of the nozzles 72 and 73 must be finished before the shed is closed.

Position 153 The reed has reached the beat-up position and has transferred the inserted uncut weft I into the fell or binding point A. As the distance between nozzle 72 in the noninserting position and the inserting position, and further the distance between nozzle 72 in the non-inserting position and the binding point, (or possibly the cutting point) is equal (see quilateral triangle ABC) the weft I is not over tensioned. The weft I is held in the space of the cutting point by a retaining thumb of a cutting device, without being cut.

The weft II preserves the position which it had in position 152. Both wefts remain in this position until position 154 is reached.

Position 154 The reed is in the inserting position and a new shed is opened. Weft II is starting to be inserted. At first, the lower retainer 98 is brought into motion. Thus, weft II is released but hook 1 00b is not closed. In that manner, the length of the cut weft II is adjusted to its optimum value in front of the nozzle 73 in the inserting position. An exact adjustment of that length is made possible by the adjustment of bracket 104b about the circumference of the circular part of the body 64 which journals the output shaft 60, such adjustment determining the extent of swinging motion of the lower retainer 98. In a further part of the swinging motion of the lower retainer 98, the groove in the introducing shields of the retainer is opened by the hook 1 00b and simultaneously, weft II is released by clamp 131.Thereupon, insertion of the weft II takes place. The weft I is in the same position as in position 152.

Position 155 The insertion of weft II is finished. The clamp 131 grips the weft II. The weft I is in the same position as in position 152.

Position 155-156 Weft II which is clamped by the weft clamp 131, is drawn out of the shed by the movement of the nozzle 73 from the inserting position into a non-inserting position, and is tensioned. The length of weft II drawn back from the shed can be changed by changing the initial position of the lower retainer 98, which is in the path of a tensioned weft II which is drawn out of the shed, thus forming a bend or loop P2 in weft II about the grooves in the introducing shields 98a, 98b. At that moment, the lower retainer 98 begins to move, that is, to swing out in the direction of movement Df the changing nozzles 72 and 73. The swinging motion of the lower retainer 98 causes a closing of the grooves in the introducing shields 98a, 98b by the hook 100b.All that was said above about the forming of a bend or loop P1 in weft I applies to the forming of a bend or loop P2 in weft II.

Weft I. Nozzle 72 starts moving from the non-inserting position into the inserting position. At the moment of tensioning of weft I, caused by the movement of the nozzle 72, weft I is cut and held by the retaining hook 1 00a of the retainer 97. Further, weft I is clamped by the clamp 130. By movement of the nozzle 72 from the non-inserting position into the inserting position, the end of the cut weft I is drawn ack into the nozzle 72. This length is adjustable in the same manner as in the case of the weft II described above.

Meanwhile the reed moves into the beatup position and the shed is then closed. The movement of the nozzles 72 and 73 must be finished before the shed is closed, i.e. the healds are arranged behind each other in a row.

Position 157 The reed has reached the beat-up position and brought the inserted, uncut weft II to the binding point A, (or possibly to the cutting point). As the distance between nozzle 73 in the non-inserting position and the inserting position, and also the distance between the nozzle 73 in the non-inserting position and the binding point A, (or possibly the cutting point) is equal (see the equilateral triangle ABC), weft II is not overtensioned. Weft II is held in the space of the cutting point by a retaining thumb of the cutting device in an uncut condition.

Weft I remains in the same position which it assumed upon reaching position 156. Both wefts remain in this position until position 158.

Position 158 The reed is in an inserting position, a new shed has been opened. The insertion of the weft I is started. First, the upper retainer 97 starts moving. Thus, weft I is released, but the hook 100a remains closed. In that man ner, the cut length of the end of the weft I to be cut is adjusted to its optimum value in front of the nozzle 72 in its inserting position. An accurate adjustment of that length is made possible by the adjustment of the bracket 1 04a about the circumference of the circular part of the body 64 which journals the output shaft 60 to determine the extent of swinging mation of the upper retainer 97.

In the further part of the swinging motion of the upper retainer 97, the groove of introducing shields 97a, 97b is opened by the hook 100a and weft I is simultaneously released by clamp 130. The insertion of the weft I then takes place. Weft II preserves the same position that it had in position 156.

One cycle of operations of the weft apparatus in accordance with the invention for jet looms provided with a weft mixing device is now finished.

WHAT WE CLAIM IS: 1. A method of controlling weft threads in jet looms which operate with alternation of insertion of different first and second weft threads, which method comprises opening a first shed of the loom, inserting the first weft thread into the first shed, beating up the inserted first weft thread, closing the first shed, retaining the inserted first weft thread in uncut condition under tension, opening a second, subsequent shed, inserting the second weft thread into the second shed, beating up the inserted second weft thread, retaining the inserted second weft thread under tension, and cutting off the first weft thread.

2. An apparatus for controlling weft threads in jet looms which operate with alternation of insertion of measured lengths of different first and second weft threads, the apparatus including a weft cutting mechanism, comprising a clamp for each weft thread, a pair of inserting nozzles mounted so that each nozzle alternately moves into an inserting and a non-inserting position, directing means with guides for each weft thread, the inserting nozzles and the directing means being arranged for swinging about a common axis, the inserting nozzles and directing means being disposed between the weft cutting mechanism and the clamp, and weft thread retainers arranged between the respective nozzle and weft thread directing means for retaining the respective weft thread when its nozzle is in a non-inserting position.

2. An apparatus as claimed in Claim 2, wherein the loom has a main shaft and an output shaft, the pair of inserting nozzles and directing means for the weft threads are adjustably arranged on the output shaft, the output shaft being journalled in a member which is displaceable relative to the stationary parts of the loom, the output shaft being positively oscillated by the main shaft

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (1)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   Position 155-156 Weft II which is clamped by the weft clamp 131, is drawn out of the shed by the movement of the nozzle 73 from the inserting position into a non-inserting position, and is tensioned. The length of weft II drawn back from the shed can be changed by changing the initial position of the lower retainer 98, which is in the path of a tensioned weft II which is drawn out of the shed, thus forming a bend or loop P2 in weft II about the grooves in the introducing shields 98a, 98b. At that moment, the lower retainer 98 begins to move, that is, to swing out in the direction of movement Df the changing nozzles 72 and 73. The swinging motion of the lower retainer 98 causes a closing of the grooves in the introducing shields 98a, 98b by the hook 100b.All that was said above about the forming of a bend or loop P1 in weft I applies to the forming of a bend or loop P2 in weft II.

   Weft I. Nozzle 72 starts moving from the non-inserting position into the inserting position. At the moment of tensioning of weft I, caused by the movement of the nozzle 72, weft I is cut and held by the retaining hook 1 00a of the retainer 97. Further, weft I is clamped by the clamp 130. By movement of the nozzle 72 from the non-inserting position into the inserting position, the end of the cut weft I is drawn ack into the nozzle 72. This length is adjustable in the same manner as in the case of the weft II described above.

   Meanwhile the reed moves into the beatup position and the shed is then closed. The movement of the nozzles 72 and 73 must be finished before the shed is closed, i.e. the healds are arranged behind each other in a row.

   Position 157 The reed has reached the beat-up position and brought the inserted, uncut weft II to the binding point A, (or possibly to the cutting point). As the distance between nozzle 73 in the non-inserting position and the inserting position, and also the distance between the nozzle 73 in the non-inserting position and the binding point A, (or possibly the cutting point) is equal (see the equilateral triangle ABC), weft II is not overtensioned. Weft II is held in the space of the cutting point by a retaining thumb of the cutting device in an uncut condition.

   Weft I remains in the same position which it assumed upon reaching position 156. Both wefts remain in this position until position 158.

   Position 158 The reed is in an inserting position, a new shed has been opened. The insertion of the weft I is started. First, the upper retainer 97 starts moving. Thus, weft I is released, but the hook 100a remains closed. In that man ner, the cut length of the end of the weft I to be cut is adjusted to its optimum value in front of the nozzle 72 in its inserting position. An accurate adjustment of that length is made possible by the adjustment of the bracket 1 04a about the circumference of the circular part of the body 64 which journals the output shaft 60 to determine the extent of swinging mation of the upper retainer 97.

   In the further part of the swinging motion of the upper retainer 97, the groove of introducing shields 97a, 97b is opened by the hook 100a and weft I is simultaneously released by clamp 130. The insertion of the weft I then takes place. Weft II preserves the same position that it had in position 156.

   One cycle of operations of the weft apparatus in accordance with the invention for jet looms provided with a weft mixing device is now finished.

   WHAT WE CLAIM IS:

   1. A method of controlling weft threads in jet looms which operate with alternation of insertion of different first and second weft threads, which method comprises opening a first shed of the loom, inserting the first weft thread into the first shed, beating up the inserted first weft thread, closing the first shed, retaining the inserted first weft thread in uncut condition under tension, opening a second, subsequent shed, inserting the second weft thread into the second shed, beating up the inserted second weft thread, retaining the inserted second weft thread under tension, and cutting off the first weft thread.

   2. An apparatus for controlling weft threads in jet looms which operate with alternation of insertion of measured lengths of different first and second weft threads, the apparatus including a weft cutting mechanism, comprising a clamp for each weft thread, a pair of inserting nozzles mounted so that each nozzle alternately moves into an inserting and a non-inserting position, directing means with guides for each weft thread, the inserting nozzles and the directing means being arranged for swinging about a common axis, the inserting nozzles and directing means being disposed between the weft cutting mechanism and the clamp, and weft thread retainers arranged between the respective nozzle and weft thread directing means for retaining the respective weft thread when its nozzle is in a non-inserting position.

   2. An apparatus as claimed in Claim 2, wherein the loom has a main shaft and an output shaft, the pair of inserting nozzles and directing means for the weft threads are adjustably arranged on the output shaft, the output shaft being journalled in a member which is displaceable relative to the stationary parts of the loom, the output shaft being positively oscillated by the main shaft

   through the intermediary of a transmission.

   4. An apparatus as claimed in Claim 3, wherein the axis of the output shaft is directed towards the binding point of the fabric and forms an isosceles triangle together with the axis of each of the nozzles in its inserting position and the axis of the nozzle in its non-inserting position.

   5. An apparatus as claimed in Claim 4, wherein the isosceles triangle is an equilateral triangle.

   6. An apparatus as claimed in any of claims 2 to 5, wherein the retainers of the weft threads are mounted swingably on the output shaft, each retainer has at least one introducing shield and a retaining hook, and the retainers are driven from the main shaft of the loom.

   7. An apparatus as claimed in Claim 6, wherein each retainer is formed by two introducing shields between which there is swingably mounted a retaining hook whlch is connected by a tie rod to a stationary part of the loom, the introducing shields being swingably mounted on the output shaft and being driven from the main shaft of the loom.

   8. A method of controlling weft threads in jet looms substantially as herein described with reference to the accompanying drawings.

   9. An apparatus for controlling weft threads in jet looms substantially as herein described with reference to the accompanying drawings.