Classifications

• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
  • D03D47/00—Looms in which bulk supply of weft does not pass through shed, e.g. shuttleless looms, gripper shuttle looms, dummy shuttle looms
  • D03D47/34—Handling the weft between bulk storage and weft-inserting means
  • D03D47/36—Measuring and cutting the weft
  • D03D47/361—Drum-type weft feeding devices
  • D03D47/362—Drum-type weft feeding devices with yarn retaining devices, e.g. stopping pins
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H59/00—Adjusting or controlling tension in filamentary material, e.g. for preventing snarling; Applications of tension indicators
  • B65H59/40—Applications of tension indicators
• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
  • D03D47/00—Looms in which bulk supply of weft does not pass through shed, e.g. shuttleless looms, gripper shuttle looms, dummy shuttle looms
  • D03D47/34—Handling the weft between bulk storage and weft-inserting means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2701/00—Handled material; Storage means
  • B65H2701/30—Handled filamentary material
  • B65H2701/31—Textiles threads or artificial strands of filaments

Definitions

• the invention relates to a device for detecting and / or setting a tensile force in a thread, which has deflection elements for the thread, one of which is movably held by means of a holding means, the holding means having a device for detecting and / or adjusting its movement and / or its position and / or its exerted torque and / or its exerted holding force.
• An electric motor drive is assigned to the two-armed lever.
• the force required for pivoting which is determined by measuring the electrical power, is representative of the thread tension or thread tension. It is further known (GB 2,125,072 A) to load an electromagnetic drive holding a middle deflection element with a constant drive force. The deflection of the arm, which is detected by means of an optical device, is a measure of the thread tension or thread tension.
• a thread brake for an entry system of a weaving machine is also known (WO 00/44970), which is arranged between a prewinding device and a main blowing nozzle of an air-jet weaving machine.
• the thread brake consists of two stationary deflection elements and a middle deflection element that is held in a movable manner.
• the position of the movable deflection element is changed according to a program.
• the position of the middle deflection element is recorded and compared with a target position selected according to the program.
• the target position is changed to an electric motor drive adjusting the middle element so that the deviation between the actual value and the target value is largely eliminated.
• the thread tension in the thread section after the middle deflection element is greater than the thread tension force in the section before the middle deflection element due to the influence of the friction between the thread and the deflection element.
• the force with which the holding means holds or supports the middle deflection element is thus dependent on the coefficient of friction between the respective material of the thread and the deflection element. Since this coefficient of friction is not known in most cases, a correct statement about the thread tension or the thread tension is not possible in this way. This applies in particular to high thread speeds, since it must probably be assumed that the coefficient of friction between the thread and the deflection element is not independent of the thread speed.
• the invention has for its object to provide a device of the type mentioned, in which a statement about the thread tension or the thread tension is possible without the coefficient of friction between the respective thread and the movable deflection element is known.
• the holding means is designed and / or mounted in such a way that the movement and / or position and / or the torque and / or the holding force of the deflecting element held movably essentially depends on the tensile force in only one thread section is dependent, which is located upstream or downstream of the movable deflecting element. Since in the embodiment according to the invention the movement and the position of the deflection element and the associated holding means only depend on the tensile force in a thread section, the signal derived from the movement and / or the position and / or torque and / or holding force of the holding element is directly proportional to the actual thread tension, without having to make a calculation using the coefficient of friction.
• the holding means for the movable deflection element is a swivel arm, the swivel axis of which coincides at least approximately with the deflection point of one of the adjacent deflection elements.
• the thread tension between the movable deflection element and the deflection element coinciding with the swivel axis runs essentially in the longitudinal direction of the swivel arm, so that this thread tension does not exert any torque on the swivel arm.
• the torque exerted on the swivel arm is therefore dependent on the thread tension in the other thread section.
• the signal obtained thus directly represents a thread tension, which does not have to be calculated with the aid of a friction coefficient.
• the pivot axis of the swivel arm coincides at least approximately with the deflection point of the deflection element, since it lies in front of the movably deflection element in the thread running direction. It is provided in a further embodiment that the movable NEN deflection element in the thread running direction subsequent deflection element is arranged at a distance which is greater than the distance between the movably held deflection element and the deflecting element preceding in the thread running direction. The greater the distance between the movable and the subsequent deflection element, the smaller the difference between the measured thread tension force and the thread tension force after the stationary upstream deflection element.
• the device is arranged within an insertion system for weft threads of a weaving machine. It is particularly advantageous if the device is designed as a thread brake for a weft insertion system of a weaving machine.
• Such a device can also perform a further function in that it is designed as a device for pulling back the weft thread of a blowing nozzle of an air-jet weaving machine.
• the swivel arm can be brought into a corresponding position by means of its electric motor drive if the weaving process is interrupted.
• FIG. 1 shows a schematic diagram of a device according to the invention
• Fig. 3 schematic diagrams of a device according to the invention, the only in a partial area of its entire adjustment range allows the thread tension to be determined independently of a coefficient of friction,
• FIG. 4 shows a schematic representation of a device according to the invention, which fulfills an additional function as a thread clamp
• Fig. 5 is a schematic representation of an insertion system for weft threads of air jet looms with a device according to the invention
• Fig. 6 is a view of a practical embodiment of a device according to the invention.
• a thread 10 runs through a first thread deflecting element 11 designed as a thread eyelet, through a second deflecting element 12 likewise designed as a thread eyelet, and through a third deflecting element 13, which is also designed as a thread eyelet.
• the first deflection element 11 and the third deflection element 13 are arranged stationary at a distance L.
• the intermediate deflection element 12 is held movably by means of a swivel arm 14.
• the swivel arm 14, which has a length r, can be swiveled about a swivel axis 15 which coincides at least approximately with the deflection point for the thread 10 formed by the first deflection element 11.
• the pivot axis 15 is connected to an electric motor drive 16.
• the thread tension is increased on each of the successive non-rotating deflection elements.
• the thread 10 comes with the thread tension from F 4 to the first deflection element, at which the thread tension is increased to the value F 3 .
• This thread tension F 3 is increased due to the friction on the deflection element 12 to the thread tension F 2 , which in turn increases on the deflection element 13 to the thread tension Fi with which the thread 10 leaves the device.
• the thread tension is increased at each deflection point by the factor e ⁇ ⁇ .
• e means the basis of the natural logarithm, ⁇ the coefficient of friction between the thread and the deflection element 11, 12, 13 and ⁇ the wrap angle between the thread and the deflection element.
• the thread pulling forces F 3 and F 2 act on the U steering element 12. Since the swivel arm 14, which holds the deflection element 12, is mounted in such a way that its swivel axis 15 coincides at least approximately with the deflection point of the deflection element 11, the thread tension force F 3 runs essentially in the longitudinal direction of the swivel arm 14 and thus almost perpendicular to the swivel axis 15 Thread pulling force F 3 therefore does not cause any torque on the swivel arm 14, ie no torque that practically falls into the wiped state. The torque acting on the swivel arm 14 is therefore determined exclusively by the thread tension F 2 .
• the torque M d r caused by the thread tension F 2 is caused by the component of the thread tension F 2 , which runs perpendicular to the swivel arm 14 through the deflection element 12. This torque is calculated using the following formula:
• Mdr r ⁇ F 2 • cos ß.
• r means the length of the swivel arm 3 and ß the angle between the direction of the thread tension F 2 and the right angle to the swivel arm 14.
• the angle ⁇ can also be expressed by an angle ⁇ , ie by the angle ⁇ between the swivel arm 14 and the connecting plane between the two deflection elements 11 and 13.
• This angle ⁇ is integrated into the electromotive drive 16.
• th angle encoder can be detected, for example by an encoder disk integrated into this drive 16.
• the thread tension force can be determined from the motor torque that can be measured or ascertained on the electric motor drive 16.
• the central deflection element 12 can be brought into a predetermined deflected position by means of the electric motor drive 16.
• the power consumption of the electric motor drive 16, which is required to hold the deflection element 12 in this position, is representative of the torque M dr and thus also of the thread tension F 2 .
• the device according to the invention is used, for example, as a thread brake which can be switched on at a specific point in time. If the braking effect is to be detected via the thread tension F 2 , this can also be done, for example, via the power consumption of the electromotive drive 16. In this case, tests are used to determine which current consumption is required for the electromotive drive in order to bring the swivel arm 14 with the deflecting element 12, including the motor rotor, into a plurality of successive angular positions. These stored values can then be compared with the current consumption which is required to achieve the same angular positions against the effect of the thread tension F 2 at the same speed. The course of the thread tension during braking can thus also be recorded.
• the electric motor drive can consist, for example, of a servomotor. However, it is also possible to use proportional rotary magnets that have a simple, linear relationship between torque and current consumption regardless of the position of the motor. Drives with different designs can also be used, in which the torque applied can be detected or determined. The torque can also be measured using a suitable measuring device, for example on the motor shaft.
• the measurable or determinable torque Mdr corresponds to the applied engine torque Mmo to r minus the mass moment of inertia of the swivel arm 14 and the electric motor drive 16.
• the mass inertia J can be determined in advance and is then known.
• the mass moment of inertia is the product of mass inertia J and the acceleration b.
• the acceleration can be detected via the movement sequence of the electric motor drive 16. Since the torque M can be continuously determined dr b by means of detecting the engine torque M moto r and what the current HR acceleration, the yarn tension can be continuously determined.
• M dr Mmotor - J • b
• the torque M d r is equal to the motor torque M mo tor. If the device is used on a weaving machine, for example as a thread brake, it can be provided that the swivel arm 14 is silent for a (short) period of time stands, for example in its end position. In this position, the tensile force in the thread can be easily recorded. In other positions through which the swivel arm moves, the size of the acceleration b must be determined.
• Functional checks can also be carried out by means of the device, for example it can be determined if there is no thread. Too much acceleration or too much expansion or a missing torque in the deflected state can indicate a thread break.
• Various methods and measuring devices can be used to determine the angular position and the acceleration of the electric motor drive 16 with the swivel arm 14 and the deflection element 12.
• an angular velocity sensor For example, the electrical voltage induced in a stationary coil by means of a moving magnetic field can be evaluated, which is proportional to the speed of this magnetic field. If a permanent magnet is connected to the axis of the electromotive drive 16, the induced voltage can be detected in a stationary coil. The induced voltage then only has to be calibrated at the speed of rotation.
• the angular position can then be obtained by integrating the speed, which can be done by numerical or digital signal processing.
• a stop can be used be, which is for example in the common plane of the stationary deflection elements 11, 13 and which sets the detection device to zero in each case before a braking operation.
• angular velocity transducers can also be used. It is also possible to use angular accelerometers that already provide acceleration as an output signal. It is also possible to use sensorless motor control techniques, i.e. to do without a position encoder. As soon as a motor starts to turn, a reverse voltage is induced in the stator coils. This inverse induced voltage, which is related to speed, can be measured. If this position is known, the position can be calculated and used as a feedback signal for the motor control.
• a further deflecting element 17 is provided, which can be used to brake the thread 10 when the brake arm 14 with the deflecting element 12 extends beyond the connecting plane between the deflecting elements 11 and 13 (in the drawing ) is moved down.
• the thread then lies against the deflection element 17, so that the braking effect is increased significantly due to the friction on this deflection element 17.
• the torque required to reach the position shown in FIG. 2 and to hold this position is no longer dependent only on geometric variables when the thread wraps around the deflection element 17. Rather, there is then a dependence on the coefficient of friction between the thread and the deflection element 12.
• the swivel arm 14 may be advantageous to limit the movement of the swivel arm 14 in one or both directions by means of stops which can also be displaced if necessary.
• stops which can also be displaced if necessary.
• the device according to the invention as a thread clamp if, for example, the incoming thread 10 is de-energized.
• the electromotive drive 16 moves the swivel arm 14 until its deflecting element 12 'runs against a stop 18 and thereby clamps the thread 10.
• the function of the device according to the invention is not dependent on the running direction of the thread. If, for example, the running direction of the thread 10 were reversed in the exemplary embodiment according to FIG. 1 (or if the pivot axis 15 of the pivot arm were placed in the region of the deflecting element 13 such that it coincides with its deflecting point), only the thread tensile force would be the same cause a torque in a thread section between the movably held deflection element 12 and the stationary deflection element 11 or 13.
• FIG. 5 schematically shows how a device according to the invention is installed as a thread brake in a weft insertion system of an air jet weaving machine.
• the weft thread to be inserted is drawn off from a bobbin 20 and deposited in turns on a prewinder 21.
• the end of the weft thread of this bobbin 20 is connected to the beginning of a supply bobbin 22.
• the insertion of weft threads from the bobbin 22 is continued, the thread end of which is then connected to a further bobbin to be reattached.
• the weft thread 19 runs from the pre-winding device 21 through the device 23 according to the invention, which serves as a thread brake, to a main blowing nozzle 24 which is connected to a compressed air supply, as indicated by an arrow.
• customary Licher such two main blowing nozzles 24 are connected in series, which are arranged on the entry side of the loom.
• the weft thread 19 is guided in a weft insertion channel 25 of a reed.
• the transport of the weft thread in the weft insertion channel 25 of the reed 26 is supported by a plurality of relay nozzles 27 which are arranged at regular intervals over the reed 26.
• the weft thread arriving at the end of the reed 26 opposite the main blowing nozzle (s) 24 is caught by means of a suction nozzle 28.
• the reed 26 also has a weft monitor 29 installed, which monitors the arrival of the weft 19.
• the weft thread 19 is released on the prewinder 21 by loosening a pin 30.
• a detector 31 By means of a detector 31, the number of turns drawn off from the drum of the pre-winding device 21 when the weft thread 19 is inserted is counted.
• a signal is given by means of which the device 23 serving as a thread brake is actuated.
• the weft thread 19 is neither deflected by the device 23 nor by a tension sensor.
• the electric motor drive 16 pivots the swivel arm 14, which is mounted in the region of the deflection point of the deflection element 11. The weft thread is thereby deflected and braked.
• the braking effect can be set by means of the device according to the invention and, if necessary, also regulated.
• the maximum braking force is set or regulated or limited.
• the maximum braking force is measured in the manner described via the tensile force in the thread section after the movable deflection element 13 and compared with a predetermined target value.
• the braking effect can be regulated in such a way that a predetermined thread tension is not exceeded. If the thread tension becomes too great, the braking is reduced, ie the deflection is reduced, to avoid thread breaks.
• another variable acting on the thread for example the quantity and / or the pressure of the compressed air blown out of the main blowing nozzle, can also be changed. This can also be done manually, for example, when setting a machine, in particular an air jet loom.
• the deflection of the swivel arm 14 with the deflection element 13 is then changed such that a match between the measured thread tension force and the predetermined target thread tension force is obtained.
• the course of the braking effect can also be regulated in a corresponding manner.
• the course of the thread tension in the thread section after the movable deflection element 13 is recorded and compared with a predetermined course of the thread tension in the manner described.
• the movement of the swivel arm with the deflection element 13, in particular the path and / or the speed of the movement and / or the torque exerted by the electromotive drive 16 is changed such that the difference between the measured actual value and the target value is saved as possible.
• the amount or pressure of the blowing air that is blown out of the main blowing nozzle can also be changed.
• the inlet into the main blowing nozzle 24 serves as the third deflecting element 13, so that there is a very large distance between the stationary deflecting element 11 of the device 23 and the inlet to the main blowing nozzle 24 serving as deflecting element 13.
• This length or this distance is very large in relation to the length of the swivel arm 14, so that the thread tensile force is simplified in accordance with the above Formula calculated.
• this thread tension is then not significantly different from the thread tension present in the subsequent section of the weft thread 19.
• the deflection element 12 of the device 23 is pivoted with the swivel arm in the direction of the arrow 32 to such an extent that the beginning of the weft thread 19 is withdrawn from the blowing area of the main blowing nozzle 14.
• the weft thread then remains tensioned by means of the suction effect of the main blowing nozzle 24, but without its beginning being exposed to a strong blowing air flow which could damage the weft thread 19.
• FIG. 6 shows an exemplary embodiment of a device 23 according to the invention, which is combined with a balloon limiter 33 which can be attached to the prewinder 21.
• a holding element 34 is attached to the end of the balloon limiter 33 by means of a clamping bracket 35.
• an eyelet 36 is provided, which forms the first deflecting element 11.
• a further eyelet 37 is arranged, which serves as a second stationary deflecting element 13.
• a third guide eye 38 is arranged on a swivel arm 14 which is mounted such that its swivel axis coincides with the deflection point for the weft thread formed by the eyelet 36.
• the pivot axis of the lever 14 is at the same time the rotor axis of an electric motor drive 16, which is also attached to the angular holder 34.
• the movement of the swivel arm 14 is limited by means of stops 39 and 40.
• eyelets serve as deflection elements 11, 12, 13. Instead of these eyelets, rods or rollers can also be provided as deflection elements.
• the deflection element 11, the deflection point of which should coincide with the pivot axis 15, can be arranged on the pivot axis. However, this increases the moment of inertia of the electric motor drive 16.
• additional deflection elements in the form of eyes or rods can be arranged on the brake arm 14, which effect a zigzag guidance for the weft thread 10. This does not change the fact that only the thread pulling force in the thread running direction after the movable deflecting element 12 exerts a torque on the swivel arm 14.
• the device 23 according to the invention can be used to generate, limit, control or regulate or set a desired thread tension, in particular in looms for weft threads.
• the setting can also be done manually if necessary.
• the thread tension is preferably recorded continuously. In certain applications, for example when inserting weft threads in weaving machines, detection at certain times or in certain positions may suffice.
• the determined thread tension or thread tension can also be used to trigger or start or stop partial functions of a weaving machine or the like. It can also be displayed.
• the use of the device 23 according to the invention is not limited to air jet weaving machines. It can also be used in conjunction with other weaving machines as a thread brake, for example with rapier weaving machines or rapier contactor weaving machines or like. It can also be used in other machines, in particular other textile machines, for example in spinning machines, winding machines, knitting machines, knitting machines, embroidery machines, sewing machines, tree machines, ie machines for processing threads or similarly guided objects.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Looms (AREA)
• Tension Adjustment In Filamentary Materials (AREA)
• Spinning Or Twisting Of Yarns (AREA)

Applications Claiming Priority (3)

Publications (2)

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Family Applications (1)

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• 2002
  • 2002-03-04 DE DE10210911A patent/DE10210911A1/de not_active Withdrawn
• 2003
  • 2003-02-21 CN CNB038051435A patent/CN1288059C/zh not_active Expired - Fee Related
  • 2003-02-21 AT AT03706548T patent/ATE338720T1/de not_active IP Right Cessation
  • 2003-02-21 EP EP03706548A patent/EP1480904B1/fr not_active Expired - Lifetime
  • 2003-02-21 DE DE50304948T patent/DE50304948D1/de not_active Expired - Lifetime
  • 2003-02-21 US US10/504,853 patent/US7243872B2/en not_active Expired - Fee Related
  • 2003-02-21 WO PCT/EP2003/001782 patent/WO2003074404A1/fr active IP Right Grant
  • 2003-02-21 AU AU2003208742A patent/AU2003208742A1/en not_active Abandoned

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