Patent Description:
The disclosure relates to a weft presenting arrangement used for presenting a plurality of yarns in the weft direction on weaving machines, particularly on rigid and flexible rapier shuttle-less weaving machines used in textile weaving applications.

Conventional weft presenters on rapier shuttle-less weaving machines have multiple needles (one needle for each unique yarn used) and are consequently clumsy; they require large space allocations in order to accommodate all the underlying mechanisms. Hence conventional weft presenters are fitted in bigger boxes on shuttle-less weaving machines and require delicate and precise time settings. There are some disadvantages associated with conventional weft presenters. <CIT> discloses a weft presenter comprising one rotary weft presentation device, mounted on the weaving machine and which is configured to present a plurality of weft threads.

A first disadvantage is that the weft presenter is usually fitted outside the width of reed. Multiple needles make the width of such a device much bigger. This mechanism needs cams, selector magnets, springs and timing links and all are fitted in an enclosure or box, which becomes considerably bigger with a multiplicity of all mechanical elements needed for individual needles. The weft is typically presented to the gripper near the edge of the cloth, so all the thread carrying needles with suitable closed eyelets are bent and staggered on one side from their mounting pivots, so as to reach the desired weft presentation place or point in relation to the gripper head path or stroke. Further, this staggering and bending is also needed to avoid entanglement of the threads as they are fed from one direction almost parallel to each other. There is a confined space for producing critically timed movements in that place, this brings in many mechanical limitations despite the fact that a single task achieved, which is: presenting the tiny weft thread to the passing gripper, and that too, only one thread at a time. Therefore all conventional / currently known mechanisms are irrelevantly large in space compared to the actual task being carried out.

A second disadvantage is that even in cases where the electronic versions of the weft presenting mechanisms are used, the electronic versions also use multiple needles and multiple stepper / servo motors, and require a drive motor for each individual needle for weft. Thus the size to task imbalance worsens as a large number of motors, one for each needle, occupy even more space. In addition such assemblies are expensive.

A third disadvantage of currently known weft presenters is that the size and layout of the weft presenter box in a conventional design, or even in the newer motor driven models of weft presenter, makes it necessary to cut the reed length as required for each woven width. As weft presentation is done in front of the reed, the reed has to be shorter in length, else the beat up will bang the reed on the weft presenter device. Hence the reeds are often cut to length to overcome this problem.

There is a need in the field for improved weft presenters which overcome at least some of the disadvantages of currently known weft presenters.

Provided herein are weaving machines with improved weft presenters which comprise one or more than one rotary weft presentation devices wherein, for each weft presentation device, a single needle is used for feeding a plurality of weft threads, one at a time. Further the one or more than one rotary weft presentation devices can be affixed at a suitable position along the width of the weaving machine eliminating the need for cutting reeds to fit different woven widths.

According to the present invention, provided herein is a shuttle less weaving machine comprising a weft presenter according to claim <NUM>.

Described according to the present invention are weaving machines comprising weft presenters which solve some of the problems / disadvantages associated with conventional multi yarn, multi color weft presenting systems for weaving machines. According to an aspect of the present invention, the weft presenters comprise a setup which uses only one needle for various yarns or colors of weft threads, thereby reducing the size of the mechanism to a more compact size compared to conventional weft presenters. By contrast conventional weft presenters require many needles, one for each weft thread, leading to bulky weft presenter arrangements.

The weaving machine including the redesigned compact weft presenters described herein according to the present invention comprise mounting a rotary turret type weft presenter and feeding the multiple colors (i.e., multiple weft threads) to just one needle (as opposed to having a dedicated needle for each weft thread required in the weave), which single needle feeds all the threads to the gripper effectively. The drive motion and timing setting device of the weft presenter is placed within the machine body structure away from the reed and sley. This use of a single needle to feed multiple threads, one at a time, and this separation of drive parts and the actual loom has not been described before.

The weft presenters described according to an aspect of the present invention comprise rotary weft presentation devices having a "turret and single needle multi weft presenter" design and are clamped/affixed/placed in front of the sley and reed, which circumvents the path of motion during beat up, thereby avoiding complications which arise from interference of the weft threads, the sley and the beat up action. Advantageously, the weft presenters allow for mounting the color selector anywhere along the width of the reed without interfering with its motion, while also avoiding the need for cutting the reed according to the width of the fabric being woven.

According to an aspect of the present invention, each rotary weft presentation device which is mounted on the weaving machine comprises an open eye needle, which feeds the weft to the gripper, and then the needle is ready to retract back as soon as the weft is picked up by the gripper on its course. By contrast, in conventional systems, the needle can retract only after the current filling cycle is complete. Accordingly, the rotary weft presentation devices facilitate preparation, selection and alignment of the next weft in filling position before the current filling cycle is yet to be completed, which reduces the response time needed to select weft and this is particularly useful for weaving machines operating at high speeds.

According to the present invention, the weft presenter comprises one or more than one rotary weft presentation devices. Further, the rotary weft presentation devices allow for precise timing of weft selection and also, concomitantly, allow for the weft presenter to be of a smaller size compared to a conventional weft presenter. Advantageously, the rotary weft presentation devices are mounted without interfering with the motion path of beat up parts, thereby also avoiding the need for reed length to be trimmed for each different weaving width. This mounting of weft presentation devices so that they avoid interference with the motion of beat up parts has not been disclosed before.

Another advantageous feature of the rotary weft presentation devices according to the present invention is that they can carry out the weft presentation for many colors or types of weft yarns by use of a single needle instead of conventional multi needle setups involving a separate dedicated needle for each type of weft yarn.

Furthermore, rotating shafts, links and cams are separated away from the main selector needle arrangement thereby rendering the device simple and easy to move around according to varying widths of cloth woven on a weaving machine.

The weft presenters eliminate the need for needle timing settings. The relative setting of the sley movement and the needle movement remains same at all times (regardless of the position of the weft presentation device along or across the width of the machine), thereby allowing for simple widthwise setting procedures so that the machine settings can be easily changed / reset even in the absence of a technician.

Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or angles or measurements or physical properties of materials and/or use are to be understood as modified by the word "about".

Referring to <FIG>, the weaving machine comprises a weft presentation device which comprises amounting arm (<NUM>) affixed on a mounting base (<NUM>) which is mounted on a long tee slot part (<NUM>) which is transversely mounted on the machine. The tee slot arrangement comprises tee slot nut (3a) and the mounting arm (<NUM>) is mounted securely on to the tee slot part (<NUM>) by means of at least one fastener at position (<NUM>). This completes the width-wise adjustment / arrangement of the weft selector. The mounting base (<NUM>) has a cylindrical projection at the bottom end (2a) and a square / round / elliptical / rectangular / triangular projection (2b) on its uppermost position to suitably accept a small motor (<NUM>) in such a manner that the axis or shaft (5a) of the motor is projecting towards the tip of the whole assembly. Arm (<NUM>) is bent a slight angle at point (Ia) to facilitate proper positioning of the weft thread which contacts the needle (<NUM>) which is explained further below. The motor is fitted by at least one fastener at positions (Ic) on a projection flange (Ib) on the mounting arm (<NUM>). A turret shaped and/or rotary feeding drum (<NUM>) is mounted on the projecting shaft (5a) of the motor. The turret shaped and/or rotary feeding drum is comprised of a central boss (7a) and has several through holes (7b) (also called as weft ports), where the number of through holes (7b) may vary from <NUM> to <NUM>. The through holes (7b) are made in the periphery or skirt or rim (7c) of the rotary drum / turret (<NUM>), which are so designed that they smoothly guide several independent weft threads through them. Further the holes (7b) are arranged in a staggered height or stacked up manner so as to avoid the entanglement of the weft threads upon rotation of the turret / rotary feeding drum in the forward and reverse directions (or clockwise / anticlockwise directions), in an event of presenting the desired weft thread to the gripper. The rotary / turret feeding drum has several numbers (7d) engraved / pressed / cast / attached / labeled thereon to mark the different threads of weft handled by it. Upon rotation of the rotary / turret feeding drum these numbers are indicated by a stationary pointer (Id) on the projection flange (Ib) at the end of mounting arm (<NUM>) of the weft presenting device. The bottom cylindrical projection (2a) of mounting base (<NUM>) houses suitable bearings (<NUM>) which guide a shaft sleeve (<NUM>) in both axial directions and thrust along the shaft axis in both directions.

Referring to <FIG>, the sleeve (<NUM>) has a triangular / square / hexagonal / octagonal / keyed / splined bore so as to diametrically lock a suitably shaped drive shaft (<NUM>) running in transverse direction along the width of the weaving machine. The drive shaft is suitably guided by a bearing arrangement at several places along its length. This shaft (<NUM>) is driven in an oscillating motion between <NUM> to <NUM> degrees of rotation with a precise timing, in the weaving cycle, by means of a suitably designed cam (12b) mounted on a shaft (12a) and rocker or follower bearing arrangement (12c) at the one of the extreme ends of the shaft (<NUM>).

Each rotary weft presentation device comprises a single weft presenter needle (<NUM>) having a bottom mounting end (13a) suitable for diametrical locking with the shaft sleeve (<NUM>) and an open end (13b) at the top end to catch the weft thread when presented by the turret / rotary feeding drum (<NUM>). The needle has a stem (13c) joining the bottom (13a) and top end (13c) and is shaped in such a manner that the needle's open end catches a weft thread presented to it by the turret / rotary feeding drum and brings it down in the path of the passing weft gripper. The motion of the needle (<NUM>) occurs in conjunction with the oscillation of the shaft sleeve (<NUM>) which is driven by a cam and follower arrangement (<NUM>) and the drive shaft (<NUM>) as shown in <FIG>.

At the back center of the weaving machine (insertion phase of weaving) - One or more than one rotary weft presenter devices are mounted on a weaving machine, and each rotary weft presenter device assembly is mounted with the help of at least one fastener and a tee slot nut at place (<NUM>) on a long tee slot part (<NUM>) running at a sufficient length across the width of the weaving machine in such a manner that the rotary weft presentation device can be easily affixed along a suitable position along the width of the weaving machine to accord with the width of the fabric being woven on the machine. The shaft (<NUM>) is of hexagonal / square / keyed / splined cross section so as to attain a diametrical lock with the needle mounting sleeve (<NUM>) which also runs across the width of the machine. A smooth thread guide part (<NUM>) is fitted on the oscillating sley in such a manner that it remains above the path for passage of the gripper head (<NUM>) and it is just above the lowermost position of the needle open end (13a) when the needle (<NUM>) is at its lowermost position.

From a top view of a weft presenter at the back center of the weaving machine (insertion phase of weaving) - This view shows the positioning of the weft presenter assembly as seen from the top. Mounting arm (<NUM>) is affixed to mounting base (<NUM>) and this base (<NUM>) is bolted to a tee slot part (<NUM>) which runs across the width of the machine as does the shaft (<NUM>). The arm (<NUM>) of the weft presenter is slightly angled towards the outside of the fabric width so that the weft presentation occurs from the selvedge edge (<NUM>), which holds the all the un-presented weft threads. This angle at point (Ia) also serves in easing out the weft thread passage from the weft feeder to the gripper head (<NUM>) and the projection part (<NUM>), so that sharp angles in the weft thread passage at two places are eased out which results in lesser tension on the weft thread as it is inserted by the gripper (<NUM>). The side body work or frame of the machine holds the drive cam system (<NUM>) for the drive shaft (<NUM>) in an oscillation which facilitates the needle motion at desired timings that correspond to the frequency of the weaving cycles. The placement of the drive parts away from the weft presenter mechanism itself makes the mechanism smaller and further augments its easy positioning along the width of the fabric.

As used herein, "axial through holes" in the rotary feeder drum (<NUM>) are interchangeably called weft ports and are the ports through which the weft thread emerges prior to selection for an insertion.

As used herein, the "home position for a weft thread" is the position of the weft thread prior to any weft thread being engaged by the needle for insertion, at the time of pick up by the rapier head (<NUM>).

As used herein, the "home position for the needle" is the position of the needle at its uppermost position when it is not engaged with any weft thread(s). During the weaving cycle, the needle moves from the home position to an operating position or to any intermediate position with a weft thread engaged in its open eyelet.

As used herein "software programmed for a desired fabric design" directs pick up of weft and warp threads in a desired sequence / pattern, i.e., the software is a weft and warp pattern selection program.

Description of Working: Cam (12b) mounted and fastened to shaft (12a) imparts an oscillating motion to the drive shaft (<NUM>) via the rocker and follower arrangement (12c). The timing, of the shaft's forward oscillation starts after the sley attains back center position and enters a dwell period. The reverse oscillation of the shaft (<NUM>) is completed before the dwell period of sley or reed (<NUM>) ends and beat up operation begins, therefore the motion of the needle occurs after the sley or reed (<NUM>) has stopped its motion (dwell time of the sley) and before the sley starts moving in the next weaving cycle.

The mounting arm (<NUM>) in the rotary weft presentation device overhangs above the reed and race board in such a manner that the needle (<NUM>), when lowered, engages a weft thread in its open eyelet (13a), which thread is fed from the turret / rotary feeding drum's position / port (7b) in the periphery of the turret; then the needle (<NUM>) comes down between the reed (<NUM>) and the passing weft gripper (<NUM>) so that the presented weft is picked up by the gripper (<NUM>). The weft thread is carried forward by the gripper along its path and it is cut from selvedge by the weft cutter. The thread now passes under a smooth thread part (<NUM>) and because of this guide part (<NUM>), the needle is no longer needed to keep the weft presented along the path of the gripper (<NUM>) and the needle can be retracted at this stage. The needle upon return resumes its backward retracted or uppermost position (<NUM>) which is the needle's home position.

The advantage of the weft presenter according to an aspect of the present invention is that the needle (<NUM>), as it has an open end (13a) and is augmented by the smooth thread guide part (<NUM>), can be retracted as soon as the gripper picks up the weft and the weft thread is cut from the holding selvedge. The entire weft presenter can then engage itself in selecting the next weft port / axial through hole (7b) according to the weft design program and remain ready until the current insertion cycle is completed and when the next insertion cycle begins the respective weft port is already preselected in the manner explained above concomitant with completion of the current insertion cycle. This allows for a response time of the stepper motor (<NUM>) and the concomitant selection enables ordinary stepper motors to be used. The need for extra /additional high response type stepper motors is avoided.

The passage of threads: The passage of threads is illustrated in <FIG>, <FIG> and is described as follows. Referring to <FIG> - The top view of the machine and the path of threads from the weft sensor, and tensioning device is shown. As seen in <FIG>, the threads run nearly parallel to each other as they exit the weft sensor cum tensioning device (<NUM>) and are fed to the turret / rotary feeding drum (<NUM>) through ports (7b) and run down the ports and converge at the temple (<NUM>) where the selvedge (<NUM>) is formed after prior weaving has taken place and the selvedge (<NUM>) is held securely by the cloth temple (<NUM>). When the feeding drum rotates, the point of convergence for all the weft threads remains the same and sequentially all the weft threads come in alignment with the needle tip (13a) for engagement by the needle and this is controlled by the weft selection software program. The length variation of weft threads as the drum rotates in steps is compensated for by the tension and length compensating mechanism (<NUM>).

Referring to <FIG> which show a side view of the threads converging to the temple (<NUM>), the passage of the threads is shown only between the exit end of the weft ports (7b) and the temple (<NUM>) held at selvedge (<NUM>). The needle in <FIG> is at its upward most position (<NUM>) and the weft threads can pass below the needle freely for selection when the needle comes down to position (<NUM>) as shown in <FIG>. The path of the selected weft thread is shown as deflected by the needle through route - exit port (7b) of the feeding drum, caught by the pronged open end (13a) of the needle which is also lowered to its feeding position (<NUM>) so as to intersect with the path of the rapier head (<NUM>), while the other end is still held securely by the temple (<NUM>) at selvedge formation at (<NUM>). This is an illustration prior to the weft cut operation wherein the weft thread is cut at the nearest possible point at selvedge (<NUM>) by the weft cutting device (<NUM>) and the selected weft thread is also seen to intersect between the cutter blade (22a) of the weft cutter (<NUM>). The thread guide part (<NUM>) is seen to be above the needle tip (13a), and above the rapier head (<NUM>), thus enabling the weft thread to pass below the guide part when the rapier <NUM> proceeds along its widthwise path on the weaving machine. The weft is cut by blades at (22a) as soon as the rapier head picks up the weft thread (<NUM>) lowered by the needle (<NUM>) and the weft thread is now held only by the rapier head to pass through the opened warp shed of the weaving machine. The needle can go back upwards to its position (<NUM>). When this insertion cycle is complete, the rapier head (<NUM>) returns empty and upon beat up by reed (<NUM>), the inserted weft thread gets held securely in the selvedge (<NUM>) at temple (<NUM>) and the rotary weft feeding drum (<NUM>) is again free to select another weft thread as seen in <FIG>. This sequence repeats in accord with any software program controlling the weft / fabric design. The weft threads as seen in <FIG>, <FIG> may undergo some deflection at the beat up by the reed at the tip of the reed but it is minimal and the tension compensating device at (<NUM>) is capable of compensating for this change in length due to minor changes / deflection in the path of the threads caused by the reed. The rotary weft presentation device is thus capable of being mounted right in front of the reed at a suitable position along the width of the machine. Further, a plurality of such rotary weft presentation devices can be mounted on the tee slot (<NUM>) along the machine width, thereby enabling machine weaving of complex patterns with multi- positioned multi-weft patterns such as traditional artistic weaves for India sarees, which are otherwise woven by hand.

The programmed software controlling the patterns of weft threads of the herein described at least one weft presentation devices / weft presenters also controls the warp pattern thereby controlling any desired thread design in resultant fabrics in warp as well as weft directions. Whereas the herein described weft presenter executes the weft portion of the fabric design software program, the warp portion of the fabric design software program is executed through the warp patterning device.

Claim 1:
A shuttle less weaving machine comprising a weft presenter which comprises a plurality of rotary weft presentation devices mounted on the weaving machine, wherein each rotary weft presentation device presents a plurality of weft threads, and wherein the rotary weft presentation devices are mounted side by side on the weaving machine.