DE1410731A1 - Weft guard for looms - Google Patents

Description

Weft thread monitor for looms In looms it happens that the The weft breaks. The task of the weft thread monitor, in this case the loom shut down. For this purpose, the weft thread must be continuously examined for whether it is broken or whether it is still intact. Since the weft entry, i.e. the actual Weaving process, on the classic loom, not a continuous one, but only one is a periodic process, the loom must not have one at any given moment Period to be turned off. From this it follows that the weft watcher would be pointless train as a continuously operating device. That would probably achieve that when a thread breakage occurs, it is detected immediately after its occurrence would; however, the chair could only be put down in the next due to the special loom construction from case to case (specified point in time take place within a period. That is why one investigates, with, the, weft thread monitor the filament of the eye not constantly, but only in individual, discrete ones Loom types adapted time moments., In general, this examination takes place: hl g periodically with or after each weft entryl in special. felling the examination is carried out only after every second entry, or several per entry Times or in several places within the registered or in the process of registering Thread.

To a certain extent, as a special case of the broken weft thread, the situation can arise that the thread monitor does not find any thread at all; this happens, for example, regularly when the weft material supply reel in the shooter runs out or when it comes on when changing the reel. Automatic looms the thread end of the new weft bobbin has not been threaded. So far, the following are e. to solve the problem mentioned at the outset serving devices have been proposed; 1. Be on the ark at the back of the shooting range. Arranged on a shaft, one or more rebukes pressed against the weft thread resting on the warp threads in the rhythm of the flapping movement. This feeling movement takes place before the newly inserted weft thread is struck by the drawer. If these needles find insufficient or no resistance at all on the loosely or not at all inserted weft thread, the shaft to which the needles are attached rotates at a greater angle than if the needles with correctly inserted weft thread due to its rigidity and tension are prevented from moving. This different movement of the needle shaft is used either directly mechanically or via electrical contacts to shut down the loom. In general, an interposed cam disc controls the correct stopping torque. When the shooter flies through, the rifle run must of course be released and the needles must be lifted accordingly. Since the time interval from the shooter's flight through and thus from the lifting of the needles to the actual touch moment is in the range of milliseconds, the needles must lower very quickly from the lifted state to the actual scanning state. However, this lowering movement must not be caused by free fall, but must be carried out by a controlled movement, otherwise the thread will either be severely injured or the sudden falling movement on a possibly very thin weft thread will result in an incorrect stop. It follows from this that the adjustment of the device is very critical. In particular, it becomes almost indissoluble when both very thin and very thick weft material is woven into the same fabric at the same time; the pressure conditions of the probe needles then müs- sen to an average can be set, with the result that the matter is no longer working and safe when thick thread the thin weft material against it even in a normally registered and with normal tension on the warp lifting the weft of these in the form is pushed through by small loops between the warp threads. This leads to the notorious Schuaswäohter brands in the fabric, which makes the goods inferior. 2. To circumvent the above-mentioned difficulties, it has been proposed to attach the feeler needles on one or both sides outside the web. In this device, the inserted weft thread is supported by a rust-shaped counter-bearing. Here too, however, one of the great difficulties mentioned under 1 is not or only incompletely eliminated, in that this device also has the very unpleasant property of being largely dependent on the thickness and material of the inserted weft thread, so that here too there are great difficulties as soon as thick and thin threads are woven at the same time. Another big disadvantage, which is added by the guards located far out, is that, due to the very late feeling moment, in many cases there is no longer enough time to shut down the chair. You can arrange things in such a way that you do not stop the chair until the archer has come back to the other side; but this has major disadvantages in terms of web technology. Because you have to readjust the regulator, since the last weft no more thread was inserted, which leads to a very annoying ("starting point"), especially with fine fabrics utilizes the fact that breaks stands for intact weft thread during the shooting motion of the weft thread within the protecting under a beBtimmten-tension. the thread, this tensile stress decreases. Using these different tensile stress a mounted within the protecting device, such as actuated to a nose protruding from the shooter, which transmits the command - broken thread - to the parking device via a lever system attached to the store lane. Solutions are also known for transmitting this command electrically; Inside the contactor a contact, closed and this one Closed contact with two power take-off rails attached to the outside of the contactor. tied together. When the shooter flies past, these power take-off rails are guided past two grinding brushes that are firmly connected to the drawer and that are connected to the loom's shut-off circuit. Unfortunately, the shooter does not fly in a precisely defined path through the compartment. Therefore, the transmission of the command with both mechanical and electrical means causes considerable difficulties. Experience has shown that unavoidable deviations in the form of the shooter, in its center of gravity, in the interwoven material, and then differences in the shooter's shooting etc., cause very considerable deviations from the theoretical shooter trajectory. This makes it impossible for mechanically interlocking elements to work together properly over a long period of time. The same applies to electrical grinder systems, with contact corrosion also being a factor here. One must always bear in mind that with a normal loom in a three-shift day, 2U0,000 weft insertions can take place in order to properly understand the extraordinary demands made on the safe operation of this guard device. 4. An attempt was then made, under load of the device in accordance with 3, to optically target the "broken thread" command to the: stationary. System to carry over :. .If -einem.ßteaer _Lö $ ungsvorschläge operated it as it is covered by the flap is intact weft with the decreasing thread tension a flap which is free-a transverse bore by the shooter. With each weft insertion, a light beam is sent through this hole and hits a photoelectric cell on the opposite side . When the thread is broken, the light beam has free passage through the hole and activates the parking device on the loom with the help of the impulse supplied by the photoelectric cell. However, this solution has one that adheres to all light barriers. Material part as soon as they are supposed to monitor a process that is not constantly in the. The object located in the area of the light beam plays: As soon as this object leaves the effective area of the light beam , it falls freely on the photoelectric cell, which leads to incorrect switching . For this reason , a control device that is difficult to control must be actuated with each weft insertion , which has the effect that the light barrier is not effective as soon as the shooter walks out of the light beam. 5. To evade this disadvantageous control device, according to another suggestion, the .8eflezioneprin - # - zip applied. The relapsing thread anticipation -gi "bt -'ver: ',' by means of a flap one on the drawer ahgeb @ rne3t @ te - ''' Mirror free.-The W @ = Light source emitted Lichtetrehl "we d ' ari ' this Mirror on a also firmly arranged - = rI'd Ü tl- . ' - electric cell reflects and dissolves -`to ci-eef = Iei "` the @ Abstellvoririchtüng äug. According to 'an -ancter' * en 'Terssie : this same solution - is, 'sieg der - Spiegel f: rek'ti' @@ S on the moving flap and will be at - @ lachlasri-`deir- @ '°' @. The thread tension is brought into the area of the beam emanating from the light source, while if the thread is intact, the mirror passes outside this area. In a third variant, the mirror is only tilted so that the light beam is directed to the photoelectric cell only when the thread is broken, while it is thrown past the photoelectric cell when the thread is intact due to the now changed mirror position. These mirror reflection based devices suffer. but very sensitive under the imprecise shooting flight and under the large tolerances in the position and movement of the mechanical parts that are usual with looms. This is because the optical device just described only works properly if the light source, mirror and photoelectric cell are in a precisely defined geometrical shape to one another , given by the laws of optics. If one tries to summarize the stream parts adhering to the shot guard devices that have become known up to now , one comes to the following result: In the case of the fixedly mounted devices (items 1 and 2) it is primarily the size used to differentiate between intact and broken thread, namely the mechanical tensile stress that leads to difficulties . The tension exerted on the weft thread when weft insertion depends in a very complex manner on the following factors : thread brake in the shooter; Thread deflections in the shooter; Winding mode of the weft coil; Shooter flight speed and thus pulse speed; Thickness, surface structure and weight of the weft material; Composition of multiple fibrils; Strength of twist during the spinning process; Elasticity and plasticity of the base material. All of these influencing factors are subject to natural fluctuations, and the sum of these large number of individual variations inevitably results in a very large total spread in the resulting Governing tension for the state "intact weft" On the other hand reaches the state "broken thread" from nonexistent weft until the so-called Tow shot that can take up almost the full width of the fabric; the redrawn by the shooter, broken end experiences by the air resistance and the friction on the warp threads a mechanical voltage-dependent a-mentioned of its length and upstream of all physical sizes of the weft and Kettmaterials similarly broad distribution having as the voltage the '"intact" state. These two extraordinarily wide scattering regions of tension now overlap to such an extent that the known from the experience of the shortcomings on the mechanical tension ba- eggs end Schusawächtervorrichtungen be granted. 3 to 5 are valid considerations for accommodated in the moving protecting guard in accordance with the point in substantially the same excess. the decrease in the mechanical tensile stress in the event of thread breakage detected by means of a device in the shooter is a very poor criterion for distinguishing between intact and broken thread due to the large spread and the resulting overlap of the two states of tension. As results further from consideration according to para. 3 to 5, but is in the accommodated in the moving Protect guards additionally still the great difficulty of the transfer deslommandos from flying shooters on the stationary Webstuhleystem.

Apart from these difficulties, however, accommodating the gunner in the moving shooter has the following advantages over the fixedly arranged devices: Within the shooter it is up to you to hold the running weft thread by means of a guide in a certain frame that is fixed with good accuracy and to this Place the guard device. In the case of stationary devices, the inserted weft thread is in a very imprecisely defined frame due to the inaccuracies in the shooter's flight mentioned at the outset and the general loom tolerances, which, for obvious reasons, hinders the sensing process. In addition, a certain shuttle always processes the same type of yarn within the same fabric, so that the guard moving with the shuttle only needs to be adjusted to this one variety and not to an average value between all the varieties that the fixed guard has to deal with on multi-guard looms. In order to arrive at safer working safety guard devices, two things have to be improved in the previously known devices: In all embodiments, be they stationary or mounted in the shooter, one has to work with a criterion for differentiating between intact and broken thread, the determining size in the two to differing conditions has "intäkter" and "broken thread" significantly smaller spreading widths than for the previously used size, mechanical tensile stress, the case is moving at accommodated in protecting devices addition, the transmission device of the command from the must Schützenayatem to the fixed weaving channel system are improved. According to the invention the first partial object in overall solves that as a distinguishing factor between intact and broken thread is not the yarn tension, but the thread movement is taken. It is no longer, as examined in the previously known Schuaswächtervorrichtungen whether yarn is stretched or loose, but it examines the way in which the thread at the weft entry moves. This investigation can be carried out both by the location-fixed Webatuhlsystem as the moving Protect system. The criterion proposed according to the invention is therefore well suited for devices that are permanently attached to the shield or to the drawer, as well as for those that run along in the shooter. The criterion results from the knowledge that the shoe thread falls. it is broken, moved differently than when it is intact; determining the size of the criterion, the thread movement ",,, comprises, as shown in the following, two in.den from each other to be separated states" gebroche- intact "and.". ner thread "has a significantly smaller spread than the thread tension, so that a clear distinction, with good certainty $ reserve, becomes possible. The previously used thread tension criterion can according to the invention in special cases additionally "sews " B ddarß be charged: Because it -proves aiäh with need , looms and weft materials as advantages: ha ± tweüä: @ ?. 8er = - Sehussfaänenwäehter 'certain i- äsees ° as size% Wett @ swis'clidäw @ ie intact and burned ° Söhud i3 faden aüöh - dsn 1ƒääü eedeäi @ 7 recorded, i.e. a dOr wob.lintakt@ist°; äaöeh. .. G, ;; was not entered with the normal tension, and which consequently can lead to a defect in the tissue. The previous criterion of thread tension, when used alone, is unsuitable for solving this refined task; because if its main states are already heavily smeared, it is impossible to obtain an intermediate value with sufficient certainty. On the other hand, as an addition to the criterion of thread movement, thread tension has proven to be very useful; In doing so, however, a clear separation between the two criteria must be striven for, and an auxiliary connection of the voltage criterion only makes sense if it is not uncontrollable but rather controlled, so that the broad voltage states do not have a negative effect. In the following exemplary embodiments of guard organs are shown which, by the nature of their attack, bring about a complete decoupling of the thread movement from the thread tension; in other embodiments, the natural coupling between the two quantities must be separated or at least reduced by special means. Therefore, in the latter embodiments, an additional example of the voltage applying criterion is inversely possible in a simpler manner to the main criterion of thread movement as in the former, so that they are then suitable especially when loose threads should also be detected. The decisive question of the quality of the decoupling runs as follows: "(thread Muse the question Can the same thread movement, but different thread tension of the guards both 0 as one that is" broken "like 'fintakter)" are answered yes ", means this means that a strong coupling is present, while the answer is "no" indicates a full decoupling, and the value of the voltage at which the display of the monitor from 1 to 0 skips nor features (always at the same bleibendeIadenbewegung provided) the NEN existing degree of coupling, or vice versa 'applying at additional voltage whose strength. the second-mentioned part of the object, which provides calibration in the case of accommodation supply of the filling detector in the moving Protect additionally, namely the transfer of the command from the shooter to the fixed Webstuhleystem is solved with optical means, according to the invention, instead of conventional mirrors, catadioptric reflectors (U reversing - reflectors) can be used. Such a device has the property of approximately reflecting incident light rays back in the direction of incidence; so he behaves like a Plahepiegel at normal incidence, WO However, this property remains opposed to the plan seal regardless of the incident angle or a curvature of the reflector at. In contrast to regular mirror reflection, this type of reflection is therefore referred to as "reverse reflection". Thanks to the position independence, the difficulty of precise optical adjustment that occurs when using ordinary mirrors is eliminated, and a very effective device is achieved with the device according to the invention and easy transfer of the com- mandos eystem by the moving shuttle to the stationary loom the details of the present invention, best seen in the various embodiments dare adjusting figures explained in more detail Fig. 1 - 3 show an exemplary embodiment of a Sehuesfadenwächter, the fixed position on the loom attached. and in which the movement of the Sohuas thread is examined with the aid of a mark generated on the thread by heat; Fig. 2 shows the electrical circuit diagram of the weft thread monitor and in Fig. 3 a longitudinal section through the probe head can be seen. In a further embodiment of the device according to the invention . ung according to Fig 4 is attached to an ion mark on the weft yarn, the movement of the Sohusafadene is examined relative to the stationary frame of reference with the aid of; In the figure, a longitudinal passage through the probe head is shown. pig. 5 - 6 show an embodiment, it is the relative movement of Sohuaafadens detected own surface irregularities in which to protect by means of each thread; the transmission of the command from the moving to the spatially fixed Bezugeaystem takes place optically, wherein a catadioptric reflector participates; 6 shows the current pulses which are supplied by the photoelectric cell with a broken and intact Sohus thread. In the embodiment according to FIG. 7, the gyrating movement carried out by the weft thread as it runs off the bobbin is used to distinguish between intact and broken thread ; the sampling and the command transmission from moving to stationary Bystem done etrahlern with optical means with the participation of katadioptriachen back. In the embodiment according to Pig. 8-10, the relative movement of the thread for protecting mechanically with the help of specially trained thread guides detected, and the command is transmitted with the participation of reverse reflectors by optical means from ßohützen to the fixed reference system; ! 1g. 9 shows some examples of the design of the thread guide and FIG. 10 shows examples of the design of the optical transmission system.

A stationary-mounted 13, also working with optical means Wächtervor- direction described with which the different in intact and refracted chenem thread movement shape relative Zuem fixed reference system is examined - with reference to FIG. 11; FIG. 12 shows the electrical circuit diagram of this embodiment and details of the optical part are explained in more detail with reference to FIG. Before going into the figures in detail, some of the expressions appearing in the description should be defined more precisely: The sley performs a pendulous rotational movement about an axis that is firmly connected to the shield of the loom ; the web shuttle on the other hand moves , r from the. Thread path guided - tranalatory back and forth. At this. The kinematic system composed of the three components of shield, drawer and shooter , the reference systems connected to the shield and the drawer are referred to as "stationary" and that connected to the shooter as "moved". The criterion of the "thread movement" proposed by the invention for the subchoning between broken and intact weft thread is to be understood in its most general sense. The thread can therefore move in the stretched state as a rigid body with three degrees of tranalation and three degrees of freedom of rotation . If the - still tense, but no longer stretched - thread does not move freely but is guided by some means, this type of movement is referred to as "guided thread movement" . If the thread is axially no longer under tension, but is held at both or only one end and moved with the help of these end holders, its most general movement can be composed of that of the guided ends (or the end) and one under the influences the movement carried out by gravity and air resistance. This portion of the total movement is to be called "free thread movement 11. Fig. 1s Shortly after the shuttle 1 exits the shed 2, the shuttle passes a scanning head 3 attached to the side of the web. A small permanent magnet 4 is attached in the shuttle; two elongated solenoids 5 and 6, a current surge is induced in these, which triggers the entire guard operation. In a somewhat later phase of the shooter flight, i.e., which is designated with 7, a small piece 9 of the weft thread is placed in the probe head 3 by an infrared emitter 30 -.. 50o heated above room temperature also in a third, designated 10 phase of the shuttle flight of the weft thread has reached the position 12 as a result of the point 11 (woven edge on the other side of the chair) rotational movement executed If the thread is still intact, there is now the thermal mark at the point 13, namely above the cylindrical infrared receiver 14. The current pulse triggered when the thermal mark is passed by the receiver 14 is stored in a storage network for some time. If the weft thread is torn, its end is no longer held by the fabric edge 11, and weft material is no longer unwound from the supply pulse in the shooter. The torn end of the thread is dragged along by the shooter and roughly describes a translation path composed of the Schützenflugbgwegung and the store movement, whereby the thermal mark passes from point 9 to point 15 without passing the infrared receiver 14. As a result, if the thread is broken, no pulse is fed to the storage network; The same naturally also applies if, in the special case of the missing weft thread at all, no mark could be applied. With a certain delay to the trigger pulse triggered by the magnet 4 in the solenoids 5 and 6, the storage network is queried by a clock pulse, whereby a pulse is only passed on to the actual storage device if the clock pulse does not find a stored pulse in the storage network. If, on the other hand, storage has taken place, the whole thing is deleted after querying the storage network and is ready for a new keying. Fig. 2s The two solenoids 5, 6 in the button head 3 together with the electrical switching elements summarized in 16 form a trigger arrangement which is dependent on the gunner's flight direction. This is necessary because the guard may only work when the shooter leaves the compartment, but must be insensitive to this if the shooter flies in the opposite direction, ie when he enters the compartment. The device functions as follows: When flyby of protecting at the two solenoids this happens when multiple exit first the solenoid 5. The induced by the magnet in the form of pulse 17 of the Kondeneator 18 is charged via the silicon diode 19th The subsequent discharge of the capacitor takes place much more slowly, since the discharge current passes through the diode 19 in its reverse direction. Occurring in this way behind the diode 19 greatly prolonged pulse from the mold 2U is fed to the group consisting of the two diodes 21, 22 and the common load resistance 23 coincidence network, a negative tension is applied to the point in the 24th A little later the permanent magnet 4 in the shooter passes the solenoid 6. The impulse induced in it by the form 25 is given to the other input of the coincidence network. Since the pulse 17 has been considerably lengthened, it coincides in the form 20 with the subsequent pulse 25 despite its temporal pre-shift, so that a pulse appears in the output 26 of the coincidence network. If, on the other hand, the shooter flies in the opposite direction, he first passes the solenoid 6 and only then 5; however, since no extension network is built into the output of the solenoid 6, the output pulse from 6 has already decayed before the pulse from the solenoid 5 arrives. The two impulses therefore no longer coincide, and no signal appears at output 26 when the gunner flight direction is reversed. The output pulse from 16 is delayed in a known manner with the aid of a monostable multivibrator 27 until the thread has moved further into the frame 9 suitable for applying the thermal mark. The pulse is then fed to a power switch 28, which is also made up of known electronic means such as thyratons or thyristors; This discharges the capacitor 29 in a very short time over the rotstrahler in infrastructure 8 stretched filament 30. With the pulsed emitted from the filament infrared energy thermal mark 13 is mounted on the weft. The infrared receiver 14, which consists of a lead sulfide cell , converts the energy emitted when the thermal mark slides past into an electrical current pulse. This is extended in the network 31 and fed to the coincidence stage 32. The output pulse of the multivibrator 27 is delayed a little further in a further cultivibrator 33 , namely for so long that it only arrives in the anticoincidence network 32 after the token has been received by the infrared receiver 14. This only transmits no impulse if the receiver impulse arrives from 31 and the clock impulse from 33 arrives at the same time. In contrast, if no receiver pulse was supplied by 31, the anti-coincidence network drops the Uhrimpuls supplied by 33 by and `leads densel- ben the Abatellvorrichtung to (the extension step 31 and the Antikoinzidenzetufe 32 together form the mentioned in connection with Figure 1 Speichernet-Jzwerk.); this is always the case if no signal has been picked up by the receiver, ie if the weft thread is broken or if no thread is inserted at all. Fig. 3s A longitudinal section through the probe head 3 showing its three main components: the two Triggersolenoide 5, 6, the infrared radiator 8 and the infrared receiver 14. The entire assembly is housed in a gap between the woven cloth and the shuttle boxes, and is supported by the arm 35. The upper limiting surface 36 of the laser must have a corresponding curvature having denbewegung and com- pletely free of irregularities no, which serves as part of the shuttle race when flyby of protecting. Aelbet in the probe elements are only mentioned three main, while the remainder of the electronic switching elements are accommodated in a further box remotely placed. The leads to the three main elements in the probe head are received by the channels 37. The filament 30 of the infrared radiator 8 is hermetically sealed in a hard glass or quartz tube 38 and surrounded by an inert gas atmosphere. The two sheets 39 serve as radiation screens, the inner one being designed as a parabolic cylinder and being highly polished.

The radiation is accordingly directed upwards in a wedge shape. The incoming rays are collected by the receiver 14 with the aid of a cylindrical lens 40 which is only permeable in the long-wave infrared and thrown onto the strip-shaped lead sulfide element 41. The screen 42 ensures that the entire receiver device is only sensitive in an upwardly directed wedge-shaped spatial area. The cylindrical design and the oblique shape of the three main elements of the probe head together form a particularly advantageous arrangement with regard to the strong scatter in the shooter's trajectory. Because, as is readily apparent from Fig. 1, the guard functions regardless of whether the shooter leaves his theoretical trajectory more or less in the horizontal direction. If all weft thread breaks are to be detected, a guard head 3 must be attached to both sides of the fabric web. In the case of only one-sided loading, it can happen that, if the thread is broken, the thread end pulled by the @ shooter is long enough to be detected by the tray change and held again; the next time the shooter passes, the thread is inserted completely normally and the chair continues to move. FIG. 4: A probe head with a structurally similar structure and also mounted on the loom at the same point as shown in FIG. 3 forms the basis of the embodiment explained with reference to FIG. 4. In the chamber 43 there are again two solenoids 44, 45 with exactly the same function as those designated with 5 and 6 (45 is not visible in the drawing). The shooter flies over this pair of solenoids at the point indicated by 46 and in turn triggers the guard operation with the aid of a permanent magnet 47. When the estimate continues to fly, it arrives at position 48 and thus the weft thread 49 is in the area of a spray discharge emanating from the tip 50. Some of the ions emitted by this tip discharge are deposited on the piece of thread 49. Since the firing materials usually used are consistently good insulators , this ion mark remains in place for a long enough time so that it can be registered again in the receiver head 51. The electronic part of the watchdog is completely analogous to that shown in FIG. The tip discharge 50, which is fed by a capacitor in the same way as in FIG. 2, has taken the place of the glow wire 30. The infrared receiver 14 is replaced by the receiver head 51. This consists essentially of a small metal plate 52, set up isolated and screened, connected to the grid of a sheet metal tube, in which a polarization charge is influenced when the charged weft thread approaches; this current surge is amplified with conventional electronic means and transmitted to the storage network already described with reference to FIG. 2.

The embodiment shown here belongs to a one-headed automatic loom in which the guard's head is only attached on one side, and in which it is permissible for weaving reasons that the loom is only put down after the shooter has reached the opposite side of the chair. From the point of view of the gunshot guard, this has the advantage that the ion tag can be received at a very late point in time during the shooter flight or even after it has come to a standstill. Accordingly, it is not necessary to form the three basic elements of the test head elongated and to arrange them at an angle, as is the case with FIG. 1. Because the three elements can, thanks to the relatively long period of time available for the entire watchdog process, be spatially further apart than in the arrangement according to FIG Weft thread is always within these effective ranges regardless of the gunner flight tolerances. The thread 53 is only scanned by the receiver 51 in the foremost loading position, whereby the entire receiver can be folded back around the axis 54 to protect against the jamming that occurs in the event of a faulty gunner flight. The weft thread with the mark on it is guided in front of the scanning electrode 52 through two guide slots 55 arranged in the side cover plates. The explanation of the method of operation of this arrangement based on a difference in the thread movement between broken and still intact weft threads can be completely analogous to FIG. 1 on Pig. 4 transferred. Experience has shown that the corona discharge generated at the tip 50 can be focused sufficiently sharply for the above purposes by simply connecting a grounded screen 56 upstream. To generate a sufficiently strong ionization, high-voltage pulses of 15-20 kV are sufficient. FIG. 5: In the exemplary embodiment shown in FIG. 5, the shot guard device is accommodated in the moving shooter; FIG. the command is transmitted optically. The weft thread performs a well-defined guided movement through the two guide eyes 58 and 59 fastened in the tip of the shuttle 57. An optical tube, which carries the two pins 61, 62 and the reflector 63, is inserted into a transverse bore 60. The tube is interrupted in the middle and sealed against dust by the two cover glasses 64 and 65. From the light source 67 built into the stationary scanning head 66, a parallel bundle of light rays is sent into the optical tube 60 with the aid of the partially transparent mirror 68 and the lens 69. The interest 51 focuses the parallel beam at point 70 and throws it onto lens 62; behind the Zinse 62 it runs parallel again and is reflected in itself by the k @ tadioptic reflector 63, hits the lens 62 the second time, is focused after the point 70 the second time and again reaches the lens 61 as a divergent bundle As a returning bundle of parallel rays, it again enters the Taetkopf 66 and is thrown by the lens 69 through the partially transparent mirror onto the photoelectric cell 71. With each weft insertion, the shooter runs once through the beam emitted by the probe head 66; in doing so, the thread running through the focal point 70 of the optical system moving with the shooter is scanned. If the weft thread is intact, a signal such as 72 in FIG. 6 is obtained by its relative movement to the eye paw at the exit of the photoelectric cell 71. If, on the other hand, the thread is broken, the photoelectric cell supplies an output signal according to 73 (FIG. 6). The modulation superimposed on the basic pulse is due to the surface inhomogeneities of the weft thread. This modulation is separated from the basic pulse with the aid of the high-pass filter 74 and converted into a uniform signal with the aid of a pulse former network 75. Since the signal output, in turn, inversely operating, on the other hand, such a yarn is released for intact ie at gebrochem over- or not existing thread no signal, an ON hand of Fig needs. 2 closer described Tragger- Antikoinzidenzeystem and 76 are turned on, the then forwards the final pulse to the parking device 77. The trigger pulse can be generated in an analogous manner by a permanent magnet built into the contactor. 7: The device shown in this figure is a scanning optics mounted in the shuttle, with which the gyrating movement carried out by the weft thread as it runs off the bobbin is used to distinguish between broken and intact thread . This loading movement arises from the fact that accommodated on the quill 78 turns of 79 to move the Schusafadene 80 at the end of which by the PUhrungsöee 81 against the end 82 of the coil slide away over this, and act loading, the weft yarn that rotatively on moves a cone jacket, the tip of which lies in 81 and the base of which is formed by the coil end face 82. The same fixed opto-electronic arrangement as Pig is used to scan this movement. 5 shows. The optical system moved along by the shooter is also constructed similarly to that in FIG. 5; It consists of the stripe-shaped glass body 83, cut out of a normal, spherical tin, and the catadioptric reflector 84 attached behind the weft thread. subsequently thrown back into itself by the retro-reflector 84 immediately behind it and, after passing the lens 83 again, fed back to the probe head. The rotational movement generated by the running loops 79 guides the weft thread back and forth in the focal point 86 (87 and 88 show two positions of this movement). Accordingly, the photoelectric cell of the probe delivers in a manner similar to that in Eig. 6 with an intact thread an output pulse according to 89 and with a broken or missing weft thread a pulse according to 90. Since the shooter is scanned by a stationary probe , care must be taken to ensure that the weft thread is scanned at least during the dwell time of the moving optics runs through the focal point 86 once. For this purpose, the glass body 83 is present, which must have a length of about 3 to 4 cm. This is because during the rifle flight in direction 91 the stationary scanning beam comes to rest in position 92 after a few milliseconds of flight time. If the glass body 83 were not present, the scanning point detected by the target beam would move on in the course of the flight from 93 to 94, which would disrupt the proper functioning of the device. Thanks to the lens property of always uniting axially parallel bundles at the focal point regardless of their axial spacing, one achieves that the scanning point 86 lies relative to the shooter The rotational cone described always penetrates at the point 86. This property of the interest 61 is also used in the device according to FIG. 5: Here, too, the actual scanning point 70 must be fixed relative to the shooter during the entire dwell time of the moving optics in the scanning beam, otherwise the relative movement of the thread to the shooter will not be recorded at all could. The exemplary embodiment explained with reference to FIGS. 8, 9 and 10 is again a shot guard device arranged in the moving contactor system, similar to that shown in FIG. Here, too, the relative movement of the guided weft thread in relation to the shuttle system is examined; However, while in FIG. 5 the relative movement was recorded directly optically with the aid of the surface irregularities of the thread, in the present example the movement is recorded indirectly via the detour of deformation forces. Care must be taken to ensure the natural coupling between the tension criterion and the movement criterion; an unsuitable design of the mechanical means used to detect the deformation forces can easily result in an undesirable influence from the thread tension. This is particularly the case when the forces that arise when looping around the Padenumlenketellen are to be exploited. With such a wrap, the thread tension generates normal forces, which in turn cause the usual dry sliding friction. The decisive for the uncouple point is now the that in the wrap deformation of the thread takes place, and that the thereby occurring, in the same way as the ordinary friction tangentially Toggle cross thrust forces at the usual on the loom high yarn flow rates are significantly greater than the forces generated by dry sliding friction. DA over addition, these deformation forces at sufficiently small nem Krümmungaradius of Umlenkwiderlagern and the usual high thread frame rates practically independent of occurring during the weaving thread tensions. This results in the knowledge that is essential for the following , then, when wrapped in a tangential direction, forces that are practically exclusively stress- independent act. Fig. 81 It represents the tip of a shooter. The thread 97 running off the weft spool 96 in the longitudinal direction is deflected by 90 ° in the threader 98 at the point 99 and leaves the shooter perpendicular to its longitudinal axis. The tangential forces occurring during this 90 ° wrap are used to test the thread movement . When the thread is moving, ie still intact, the 45o inclined resultant of this tangential curve deflects against the shooter's length axis, deflects the entire abutment of the wrap a little in the direction mentioned and thereby covers a back emitter located behind the jet inlet opening 101; the scanning light beam 102 can consequently no longer reach the reflector. If the weft broken it or is no such exists, directs a restoring force the Widerlager.100 in the original position, and returns the reflectors free; the bundle of light rays 102 is now reflected back into itself at the rear reflector . The stationary mounted scanning head 66 emitting the beam 102 and receiving the reflected beam again is the same as FIG. 5 shows. In Fig. 9 some examples of the design of the movable abutment are shown. These allow in particular, on the one hand, an effective decoupling of thread tension and thread movement and, on the other hand, if necessary, an additional application of the thread, which can be achieved with simple means. the voltage. In Fig. 9a, the entire abutment is made from a piece of spring steel or spring bronze. The fastening takes place on the foot piece 103 and the actual looping on the torus-shaped bent piece 104. The right-angled bent flag 105 hides the light beam falling from above onto the reversing reflector 106 in the deflected position. For the purpose of completely eliminating the influence of the thread tension, the shaft piece 107 acting as a spring is directed in such a way that the long side of its cross-sectional rectangle points in the radial direction 108; consequently, the deflection in direction 108 is blocked and such deflection is only possible in the direction of the resultant of the tangential deformation forces, that is to say in direction 104a. By rotating the shaft piece 107 in the indicated direction 109, an additional loading of the resultant of the tension forces acting in the direction 108 can be achieved. So that the continuously acting resilient shaft 107 does not result in a slow, dragging transition from the open to the concealed state, but rather an abrupt one, according to FIG. used on microswitches. If the guide torus 110 is moved under the influence of the deformation forces by the moving thread 111 in the tangential direction 112, the spring 113 changes its position abruptly to 114; the flag 115 bent at right angles on it is switched into the scanning light beam. Again, by simply changing the Bohaft- situation within the meaning of 116 an additional charge of the in Direction 117 acting voltage resulting possible. Instead of the spring loaded in the arrangements 9; a and 9b forces for resetting the deflection abutment are suitable especially magnetic forces. The same are known- Lich a negative ear characteristic such as 118 in Fig. 9o shows on; it is the distance between the two on the x-axis cal mutually attractive bodies and on the y-axis the Force applied between the two. Through this negative tive ear characteristics can be achieved in the same way as with the spring a discontinuous transition. from a state in the others the two bodies are initially in a certain distance 1.19 and one increases the attacking Force * tczessive, nothing happens at first until at Reaching the point 120 , the two bodies jump together move away from each other and move up to the end stop 121 move. Since the force leading to the tear at point 120 also remains effective later, on the other hand, the restoring force is smaller in point 121 than in 120, the state is 121 stable, and only then does the system jump in again the state 120 back if the external force effect up to to the force corresponding to the ordinate in point 121 has decreased. In addition, the negative character stik the following important advantages during the Abachues des Bohützenn the Bohusa thread is loose, and accordingly that movable deflection abutments in the idle state; in 11g. 9o is this state is represented by point 120. Here is the The restoring force is the greatest, then the Significant accelerations occurring affect the Wäohtervorriohtung less than with a spring system according to FIG. 9a or b, in which the restoring force is smallest in the rest state. In an analogous manner favorable to small in magnetic system Rüekatellkraft in the deflected state in protecting braking affect: the deflection force exerted by the intact thread is less compensated by the small restoring force of magnesium th as by the large spring, eo that the deflected state is more stable with the magnet system. By applying an additional spring force, the course of the curve 118 can be varied within wide limits; Curve 122 shows such a variation. Further changes can be achieved by e19 opposing field 123, the superposition of which with basic field 118 leads to curve 124. FIG. 9d shows how the whole thing can be implemented: The actual surface of application of the deformation forces is in turn formed by a toroidal guide plate 125 . This is extended downward through the shaft 126 with a subsequently bent at right angles Fusa 127; At the upper end, the flag 128 serving to cover the light beam is bent again. The whole is advantageously made from a piece of hardenable steel and is essentially identical to the shape shown in FIG. 9a. However, the deflection does not take place through suspension, but rather through pivoting in the cutting bearing 129; The magnetic attraction between the steel armature 127 and the permanent magnet 130 acts as a restoring force. An intermediate layer 131 made of non-magnetic material is used to set the zero point 119. The holding of the Peder force leading to the curve 122 can take place through a partially elastic design of the shaft 126 , while the opposing field 123 is generated by the permanent magnet 132. The application of the thread tension geachieht by changing in the axial position of the cutter 129 according 133. not find a 90o deflection are available, the insufficient due to the small deflection angle may deformation forces can be increased by the fact that existing with the help of the according to FIG. 9d anyway permanent magnet 130 to the yarn, an additional pressure is exerted (Fig. 9e): the thread 134 moves between the examples the guide plates 135 and 136, one of which is lower at its end flag 137 contributes to the cover of the catadioptric retro-reflector 138th The upper ends are bent at right angles and rest in the same way as in FIG. 9d in the cutting bearings 139. Two permanent magnets 141 designed as screws can be screwed into the two pole shoes 140 . The polarization of the magnets is opposite, so that the two plates 135 and 136 attract each other and thus exert pressure on the thread. The restoring force and, in the same sense, the pressing force of the two guide plates 135, 136 causing the thread deformation is changed by screwing in the magnetic screws 141 more or less strongly. By means of an oppositely polarized magnet 142 and 143 outgoing-pad transverse field drawn in by the two dashed lines, it is still possible to regulate the pressing force of the plates 135 and 136 independently of the restoring force. By shifting the cutting bearing axle 139, an additional loading of the loading stress 144 in addition to the tangentially acting deformation forces 145 can be achieved, so that the resulting 148 occurs. (Big. 9f) In another training forum according to valid. 9g, the movable deflection abutment 147 can be rotated about the axis 147a passing through the center of gravity of the entire system; storage ER- follows in the two peaks 148, 149 and the provision of With the help of the springy flag 150, which is advantageous in the art the spring shown in Fig. 9b is formed. That The entire system including the reversing reflector 151 is located in the housing 152, which only has a slot in the thread guide 153 has. The scanning light beam 154 passes through the Cover slip 155 in housing 152; the reversing reflector 151 is covered by flag 15.6 if the thread is intact. One additional application of the voltage component takes place by simply turning the whole system in that direction 157. Complete sealing against ingress of dust can can be achieved by a two-part design of the hammer 1521 which contains a partial chamber, the deflecting abutment 147a and the Rüoketell flag 150, while in the other chamber the Flag 156 and the skirt radiator 151 are housed. the The axis is supported by the partition between the two chambers. broken and the two systems of rotation are only through two themselves attractive on the gogina side, each on one of the two partial axes mounted permanent magnets coupled. With all of the in rig. 9 shown exemplary embodiment len has been given special attention, dang the Sagittarius-Absohues and -Ruffang occurring strong attacks accelerations do not have a detrimental effect; to are first and foremost the moving parts as light as possible formed, so then the acting acceleration forces remain smaller than the 8üokatellkraft. In the execution examples according to Figures 9a - 9f can also show the plane in which the Steering takes place, placed perpendicular to the Bohützenlängsachee will. Since the other degrees of freedom of movement are through the Formation of the leaf spring 107 and the cutting bearings 129 and 139 are blocked, the systems remain at the Bohützen- Acceleration and deceleration unaffected in a first approximation. In the embodiment of Fig. 9g, the same is achieved by placing the axis of rotation through the center of gravity of the rotating system. Thanks to these special wet grips , it is possible to use small angles of wrap and simple thread guides, as is the case with the ones shown in fig. 8 th gezeig- machines Protect occur to get along. It is not necessary, as in known devices Elm by multiple induced, pulley acting like multiplication wrap the thread tension for deflection to use, which is useful only for non-automatic shooter and also the thread tension as inappropriate Unterscheidungskrite- criterion used. FIG. 10a shows one for scanning those explained in Pig: 8 and 9 , im. Protect the built-in visual monitor device with suitable optics that work depending on the direction of flight. Such a directional dependency is necessary when the guard works on both sides, ie when a probe head is arranged on both sides of the web . In this case, however, the guard may only respond when the contactor runs out of the way off, not with his running. To solve this problem , the pig is in the probe head 66. 5 the partially transparent mirror 68 is replaced by the prism 158, the side surfaces 173, 174 of which are partially mirrored. Part of the beam falling from the light source onto the prism is reflected at point 159; another portion is len of the transmitted radiation reflected in the point 160, so that by means of the exiting sub-beams at different angles 161 and 162 two spatially separated images 164,165 of the lamp filament formed. The reflected by the reverse reflector in itself and partly transmitted by the prism 158 bundles 166 and 167 leave the prism likewise, so that never can be separated on each of the two photoelectric cells at different angles are directed 168 and 169th If the reversing reflector passes through the two partial beams 161 and 162 in the direction 169a, first the cell 168 and a little later the cell 169 is exposed. The pulse supplied by 168 is lengthened or delayed in network 170 and then fed to a coincidence network 171 together with that supplied by 169. If the contactor flies in the specified direction, the two pulses arriving in 171 coincide and a signal is passed on to the switching device 172; on the other hand, if the contactor flies in the opposite direction, there is no coincidence in 171 and consequently no shutdown. Details of this electronic part are explained in connection with the direction-sensitive magnetic trigger device in FIG. An important condition for the correct operation of this direction-independent probe head is the same brightness in the two spiral images 164 and 165; Since the two reflected bundles pass through both the front and the rear prism surface 173, 174, the same intensity for the two beams 166 and 167 hitting the photoelectric cells follows from this the front surface 173 has a coefficient of reflection of 0.20 and the rear surface 174 has a coefficient of reflection of 0.32. It is assumed that the Umkehrreflek- gates 100% reflection and having no scattering, so designate the intensity of the incident on the photoelectric cells beam portions transmits 11% of light emitted by the light source can pool. When Taetkopt 66 this size is un- ter same assumptions and 50% reflectivity of the mirror 25%, In Figure 10b, a further possibility is to accolade of a protecting flight explained. In the moving in the direction 175 Protect 176 177 represents the reflector belonging to the shot guard device; a pair of such reflectors is arranged one behind the other in the other tip of the shooter. When flying through, the pair of retro-reflectors 178 first pass the light beam 179 of the Taatkopfes-180 and generate a double pulse therein; a little later, the reflector 177 triggers the actual simple guard impulse . The output of the probe head a 180 constructed in accordance with 66 is fed to a pulse switch 181 which works with known means and which only emits the double pulses in one channel and only the single pulses in the other. The double pulses are extended in the network 170 or delayed and combined with the incoming from the other channel Einfachimpul- sen the coincidence network 171 is supplied, which forwards in the same way as in Fig. 10a only in Koinziddnzfall a signal to the Abetellvorrichtung 172nd A stationary is mounted 13, likewise written sawn with optical means operating guard device which different form of movement studied in intact and broken thread relative to the fixed lower system - with reference to FIG. 11. The attachment can in principle take place on the ark or on the shield of the loom, but this embodiment is particularly suitable for installation on the ark. gig. 11s The light source 183 is mounted in the middle of the drawer 182, a little in front of the store lane. With the help of a diaphragm, an upwardly directed bundle of rays is generated; this is directed against the slit-shaped entrance aperture of the photoelectric receiver 184. Transmitter 183 and receiver 184 thus together form a light barrier with a vertically lying bundle. When the contactor moves through the shed from right to left , the weft thread 185 is guided through the beam of the light barrier as a result of its rotational movement about an axis running perpendicularly through point 186. 185 and 188 or 189 and 190 denote shooters and weft thread position before and after the passage through the scanning beam. If the weft thread is broken, according to 191 it is pulled through by the shooter and does not pass the light barrier. Since only a very narrow bundle of light rays is required for scanning, it is possible to design the entire arrangement as a central weft guard, in contrast to the arrangements located laterally outside the web. Because the narrow bundle of rays makes it possible, with the help of pins attached to the reed from above and below, to divide the warp threads forming the shed to such an extent that the light beam can penetrate between them (see FIG. 13a). It goes without saying that a double-sided design is also possible , both inside and outside the fabric. WEI terhin it is possible that from the transmitter 183 and the receiver 184 existing guard actual organ is not on the charger, but stationary on Schild.anzubringen. Fig 12:.. In a large part of today in operation looms the fork or Nadelschunawächter described under section 1 are used, the process being carried only with one in the center of the loading fork arranged. For reasons of price and simplicity (assembly, replacement, mainte- nance) one accepts the experience group with around 10 - 20 ¢ of all cases to be charged and not detected by a centrally arranged guard. In addition, you just produces mainly relatively simple fabric with this type looms and the machines accordingly can run at high speeds; this has the consequence that with Sohusewäohtern arranged on both sides the time to Dormant loom is no longer sufficient. So you will. also from this side inevitably to the central ßehueswäch-. ter led. As a result, there is great interest in nem in the middle of the store lane the invention, the superior criterion of the different thread movement as the basis. To the solution eich is particularly suited to this task that of hig. 11 shown design, as the actual guardian order gan - a bundle of light rays - with simple means the warp threads forming the shed are passed through can. However, when it comes to implementation in the electrical niche part of some specific problems, which is why Pig. 12th the complete content associated with this arrangement reproduces. The whole device is fully transistorized and is therefore particularly suitable for looms usual continuous operation. The tasks of the individual switching elements ments are explained in detail where it is calibrated are special functions. With the other elements is for Paohmann the working method from the circuit diagram without further evidence, then calibrate the description limit the block diagram. The difficulties to be overcome were as follows: For the light beam between the warp threads has to defend it through which mechanical thread dividers are necessary are agile. However, they have to be used again when the leaf ossification occurs be removed from the area of the warp threads, otherwise irregularities arise in the tissue. Constructive input Features are in fig. 13a shown. Here is the one Factor of concern, then, when removing the thread dividers the warp threads in the light beam path of the guard move in and thereby trigger false impulses. It must therefore be provided means in the electronic part, which released the guard only for the short period of eigent- union Padenabtastung and him lock the rest of the time of one period. Since the present Ausführungef orm in a manner analogous to those of Figs. 1 - 7 operates inversely, must be conducted by a trigger Uhrimpuls a manufacturer that queries the storage network. Basically can. this clock pulse can be picked up by a control switch operating synchronously with the stroke movement ; that has not proven successful because the contactor from the moment of the launch moved to an independent kinematic system and is no longer coupled to the spatially fixed loom system. The cycle times given by this stationary system are therefore no longer readily valid for the moving Sohützene system. This results in serious adjustment difficulties in practice, in that the movement sequence of the Schützeneyeteme cannot simply be simulated , as is possible with the stationary loom system, by letting it run slowly. This is because with such a simulation the elastic deformations and mass effects that only occur at the normal high speeds and accelerations have to be disregarded, which experience has shown leads to great difficulties. One therefore strives to make the triggering of the moving shuttle system, and for the ready has based on other embodiments described bene magnetic device particularly useful good; it is therefore also used in the present embodiment. Closely related to this problem, the task of the pulse extension is in Anticoincidence network of Speiohereyeteme as Were you encountered in previously discussed Ausführungeformen When the kick pulse is entered once into the extension network depends the hang of the output pulse only by electronic means and can the loom can no longer be influenced ; If there are any changes in the electronic part, there is always the risk that the extended impulse "runs away" as a result of the lack of coupling with the cycle system of the loom. For this reason it is very important that the pulse lengthening system is rigidly coupled to the Webst-uhlo system; This task is also achieved by the electronics explained in FIG . Another special feature of the central guard is that it has to work on both sides, ie when the shooter is flying to the right or to the left. The Vorrich- must tung therefore completely right-left symmetrically be built up. One of the two trigger solenoids 192, 193 is attached to each of the two trigger solenoids 192, 193 (Fig. 12a) at a distance of approximately one shooter's length to the left and right of the actual guard 183, 184. The outputs of the solenoids are each connected to the input of the monostable multivibrator 196 via a decoupling diode 194, 195. The pulse shapes that occur and their relationships are explained with reference to FIG. 12b: When the permanent magnet built into the shooter flies past , the solenoid 192 delivers the pulse 197 and the solenoid 193 the pulse 198; the two pulses are shaped in pulse shaper multivibrator 196 in the two Rechteckimpulee environmentally 199 and 200 which hang by that of the pulses is determined 197 and 198 and trigger assembly depends on the geometry of off; in the present case it is 2 * milliseconds.

The pulses 199 and 200 are differentiated in the RO element 201 and lead to the pulses 202 and 203. A bistable multivibrator 204 is described with the two positive peaks of 202, 203, which generates a pulse of the form 2o5. ready. This pulse controls the AND gate 206, which opens the receiver channel. With the negative peaks of the two pulses 202 and 203, another one becomes more bistable. Cultivibrator 207 actuated which provides an output from mold 208 . This pulse is differentiated in the network 209 and leads to the two pulses 210, 211. The positive pulse 210 is cut off with the aid of the limiter diode 212, so that one of the form 213 remains as the actual pulse. Much of the matter now is that the Uhrimpuls 213 is still within the over- swept by the gate pulse 205 time period. The while passing the weft yarn through the light barrier of the lichtelektri- rule cell 214 supplied pulse 215 is amplified in amplifier 216 to about 104 times, and provides the Ausgangeimpule 217. servant via the con- trolled by the pulse 205 and gate 206 to the monostable ldultivibrator 218 supplied. The output pulse 219 is applied to one input of the anticoincidence stage 220, which thus blocks the passage of the pulse 213 arriving from the limiter 212. If the thread is broken, no pulse 219 enters the anticoincidence stage ; the clock pulse 213 is allowed to pass and is extended to the form 222 in a monostable cultivibrator 221. 222 has a duration of approx. 0.4 seconds, which is sufficient to actuate the Abetellmeohanismue actuated by the output stage 223 and the electromechanical relay 224. The entire arrangement fully meets the requirements set out at the beginning : It is only sensitive during the moment of touch (AND gate 206, pulse 205) - the clock pulse is triggered by the shooter 185 himself (trigger oleroids 192 and 193) - all critical times are rigid with the loom coupled (trigger oleroids 192, 193) and can be change in distance between the triggers and the actual be set. The arrangement work- tet full left- right -symmetrisoh, (magnetic trigger 192, 193 and blocking diodes 194, 195), and still they need electronic elements except the two magnetic triggers * and the blocking diodes only to be present in number. Big. 13i Looking at the Big. 13a is particularly in cross section the effect of the two pad dividers 225 and 226 can be seen. Loading move the drawer from position 227 to position 228, in this way, these parts, which are designed as pointed pins, ler as a result of the now open brook in the area of Hettfäden and thus give the sent out by the transmitter 183 Light beam 229 free, so then it is picked up by the receiver 184 men can be. 230 illustrates the position of the shooter in the coming of the pad scanning. The transition from that to Big. 11 explained rotational movements went ih a translatorisohe with broohem loading is in general by the Luftwierderetand and the one behind the Protect generated air flow forced. By * in small, horizontally acting fan 231 (] Fig. 13b) can additionally be achieved, dars in the event of a thread breakage Thread 191 moving freely behind the Bohütsen. next to the effective area of the bundle of light rays runs; this results in certain! 11111n for the Assembly of the actual guard organ Ver # intsöfiungen. In the event of a thread breakage, the shooter 6 pulls gene Udo 191 a disengagement caused by the sigengewioht slight downward movement; this movement. can also can be used to distinguish the broken from the intact bathing The thread 232 (Fig. 130) passes through the free falling movement in the area of a pin 226, to which examples weep the lower yarn divider can be used, and is prevented by this pin during further movement the shooter in the area of the Light beam to come. Also, these free thread downward movement may be optionally additionally accelerated overall by a small, by acting below blower 233. In addition, the contactor läset form so that occurs in its flight to the rear end downwardly directed air flow, the vertical movement of the thread brings about. This vertical movement can also by optical means erfaaat becoming in height 234, in which the intact Fa to 188 @eine Rotationabewegung performs (Fig. 13d), is det abgebil- a point light source or a pinhole. The illustration scale is to be chosen so that the entire beam of rays is covered as far as possible when the padenduro runs . The broken thread 232 crosses the bundle 235 as a result of its additional, downwardly directed movement component not in the image point 234, but somewhat deeper. At this point, however, the light beam cone has a considerably larger diameter than in the image point 234, so that a correspondingly smaller portion of the beam is covered by the thread 232 passing through. In the following FIGS. 13e- i, the optical parts belonging to the embodiment according to FIG. 11 are discussed in more detail. Big. 13e shows the simple sole optics from the light source 236 onto the slit diaphragm 23? thrown shadows 238 the padenn 188 slides over the aperture hole $ 240 as a result of the ? ad-enrotation movement 239; an attached behind the slot lichtelektrinohe cell 241 is obscured by a short time and supplies a current pulse which electronically in accordance with FIG. 12 is weterverarbeitet.

13f shows a light barrier which additionally has a sensitivity gradient in the vertical direction and whose function was briefly explained with reference to FIG. 13d : The. approximately punctiform helix 242 of light source 243 is imaged at point 245 with the aid of interest 244. The divergent bundle 246 emanating from here falls on the photoelectric cell 247, which supplies a current pulse of different sizes , depending on whether the intact pad 248 rotates horizontally through point 245 according to 249 , or the broken 250 translationally with an additional vertical movement 251 the cone of rays crosses below the point 245th In order to avoid a large-area light-electrical cell 247 , the divergent bundle 246 can be focussed with the aid of an additional lens 252 . FIG. 13g shows, in cross section, an arrangement analogous to FIG. 13f, but in which the light source 243 and the photoelectric cell 247 lie on the same side of the thread 248 or 250 to be scanned. This arrangement brings structural simplifications with it, in that the electrical elements lie next to one another and can be accommodated in a common housing. The recycling of the light beam ER is advantageously followed by a katadiöptrischen, Rücketrahlere 253; The exiting and entering of the bundle of rays are separated with the aid of the partially transparent mirror 254 . At occurs in the case of the according to Pig. 11 utilized thread movement criterion following Difficulty arises when harvesting weft insertion after successful The thread end is not pulled from the fabric edge held in point 186, but by a special holding device at the level of the shop floor. Therefore, the thread does not carry out the first shot after a change in a rotational movement around the point 186, but such at the further outside and more rearward point 187. Kan can take this into account by then not a single point in the plane of rotation 249 245, but rather a row of points 255 (FIG. 13h). Thanks to this measure , the light striking the photoelectric cell 247 is nevertheless modulated in its brightness, regardless of whether the intact thread 248 passes over points of the row 255 at one or the other end . The generation of the dot row 255 can for example follow ER, then the illuminated by the Soffitenlempe 256 Loohblendenreihe 257 by means of the lens is ready to 258th A similar solution doughs Big. 131e The thread 248 or 250 with the help of the light source 259 beleuohteti serve lighting is advantageously carried out in by means of the encoder. 260 generated parallel light 264, but the codensa tor biting enough point-shaped light source also left out. be sen. Which is in the object plane of the lens 261 wegende Baden 248 is featured on the Loohblende series formed inlet opening 262 of the Liohtelektrisohen cell 263 pictured. The modulation is done by walking past of the sharp thread pattern 265 in front of the row of loops. At the Passage of the broken thread 250 is the figure in- follow the incorrect distance between thread 250 and the lens 261 out of focus and the ßtromi <pulee accordingly less high. When the thread free movement 251 down should not be exploited, just the difference between the rotary with intact thread and the translational toric movement in the case of a fractured, eo lens 261 can also be omitted; This then results in a very simple Bohattenoptik in the manner shown in Fig 13e. shown, 240 wherein instead of the single aperture, a series of diaphragm 262 occurs. To sum up, following the discussion of the various embodiments of the invention Bchueswäahtervorrichtung following Sagent 111e from Grensen variety of possible embodiments is clear, 1Kest the inventively proposed .. criterion of yarn movement a much greater leeway in choosing the actual Abtastorgann than the known The thread tension criterion is the case . The deeper (about für.diese fact is that dig voltage is a mechanical force, ie, a physical in size, which can be measured that is generally recognized only characterized by never act on a man or in the more general sense to matter läset. in contrast, the term * "movement" is the velocity based on representing a purely kinematic size, and consequently without going through the mass action detected, or can be measured. It has therefore the choice of Menemethode for the Grönse "movement" more opportunities, and what is important in this case, above all, the measurement can contactless if necessary without a hitch, that is to say without maneuvering effect. With regard to the spread in the two states "intact ter Sohussfaden "and" broohener weft thread "is that . Criterion of wheel movement the criterion of thread tension basically superior: the weft thread to be inserted is inevitably guided on the loom through the drawer and the shuttle; if the thread is broken, there is still an inevitable guidance of one end. Since both the speed of the store's movement and the shooter's flight speed are subject to only insignificant fluctuations in a certain loom and a certain fabric, and on the other hand the guiding movement of the weft thread no longer depends on any other parameters, the movement criterion basically shows very small scatter in the two states of interest here . It is not the same as with the voltage criterion that the two states to be distinguished are naturally smeared, but the states are fundamentally sharp and smearing can only occur through inept control from the measuring system. As a result, the quality of the individual embodiments and their usefulness for the various types of loom also differ only in this point. The forms of movement of the weft thread used in the individual application examples are fundamentally equivalent; A condition for the possibility of use in a weft monitor device is that the relevant form of movement when the weft thread is broken is as different as possible from that when the thread is intact. The measurement methods or the detection of the two states must of course be adapted to the individual forms of movement; If the measurement, ie the investigation, is contactless, that is, without mass action, the decoupling mentioned in the introduction between the motion and the tension criterion is complete, since the tension forces cannot work without matter; Conversely, it follows from this that mechanical means are always necessary for the purpose of additional thread tension misalignment. The Beaufechlagung can be done in the most general sense that one can overcome the force Paden at transition from one state to another with the help of his own stress a counter, that the transition must not directly, but only through a potential barrier. This can be done for example in the probe head to Big. 4 achieved in that one blocks the entrance of the guide slot 55 by a small leaf spring, so that only the intact, and is under normal tensile stress weft thread in the rear position 53 passes and can therefore be detected by the receiver, while the loose erroneously registered thread the spring cannot bend sufficiently so that it does not reach the position 53 and accordingly cannot be perceived by the recipient . The same effect can be achieved in this and, in an analogous manner, in the other exemplary embodiments, by means of the two ? 1g. 13b and 13e reach the fan shown. With the exception of the reference to Figs 8 and NEN beschriebe- 9, ne otherwise angetroffe- in all embodiments complication of the inverse operation with the necessary thereby triggering and coincidence devices joined examples NEN deeper reason in the following Tatesche. In addition to the two main states "Intact" and "broken bathing" the borderline case of the thread not inserted at all must be recorded , whereby the same notification should be triggered as in the case of a thread break. Since a thread that is not there at all cannot move and can not trigger a signal, one has to force the brook to reverse it and derive a signal from the intact thread. In contrast, the embodiment is shown in Fig. 8 and 9. Here come the beige solid for scanning mechanisehen means zuhilfe, thus reversing the Inf ormationeabgabe already take place in the actual scanning knows matters arising from the moving thread Def * ormationekräfte must overcome a counterforce, so then if there is no thread, this takes effect and generates a signal. The use of electronic means in a shot guard device brings with it the decisive advantage in many cases of a faster mode of reaction, this advantage being particularly evident in the case of guards arranged on one side. Then applied at the accommodated in the moving devices Protect signal transmission by optical means, of which the special Yerwen4ung reverse reflectors for recycling waste deb tantetrahlee, chairs the usual large tolerances of the web ,. the strong vibrations and high speeds extremely well angepaent. The used for scanning, per se known electro-optical Abtaetvorriohtung allowed by the coaxial Lichtetrahlenverlauf and thus achieved utilizing the central beams of the scanning bundles the hutzbarmachung the spotlight the back own extraordinarily high discernment against the diffuse ambient reflection, sodast with the guards a ungewähnlich high Betriebseieherheit reached can be. That in the pig. The embodiment shown in FIGS. 8 and 9 requires some explanations as a special case. In this embodiment , thanks to the signal inversion in the actual scanning element, the outlay on electronic means is relatively small. By eliminating the entire trigger device is also mounting on the loom considerably simplified, and because the guards in the moving Protect system is that these arrangements are inherent special benefits, such as those conducted in the on nY.her explains added. With the aid of catadioptric reflectors for signal transmission from moving into the fixed reference system is a very effective and simple failure device produces so-with a total. On the other hand , in this embodiment, by detecting the thread movement with the aid of mechanical means , one naturally comes into the range of the tension criterion, and the means explained in greater detail in FIG. 9 must be used so that a sufficiently good decoupling can be achieved. In this case, it is above all a matter of using forces which are speed-dependent and as weakly voltage-dependent as possible to generate the signal , while for the actual yarn braking, on the other hand, using forces which are as independent of the speed as possible. Deformation forces are suitable as the former , and dry friction forces as the latter. As in the examples, the deformation forces, overall showing was produced at a Padenumlenkung with small Ki-Ummungsradius; the thread is primarily deformed when it is bent, and the work performed during the thread movement is contrary to the flexural rigidity. With this deflection, a transverse contraction of the thread takes place at the same time, which can be intensified by external pressure forces; the external pressure forces are particularly effective when the abutment has a small area. So that large frictional forces do not occur at the same time during deformation, the coefficient of sliding friction of the thread guide should be small. In contrast to this, in addition to friction, as little deformation as possible must occur on the thread brake; for this purpose, the counter-bearing should have a high coefficient of friction and a large area, so that the normal forces generating the friction deform the thread little. With all thread guides in the shuttle, it is essential to avoid large angles of wrap; because according to the laws of rope friction, the tensile stress increases exponentially with the angle of wrap, with the coefficient of friction occurring in the exponent. Due to the unavoidable thread inhomogeneities, the coefficient of friction is also subject to fluctuations, so that the normally usual values with the wrap angle should not go beyond 900 , as otherwise, due to the exponential relationship, the fluctuations in the coefficient of friction have a very large effect in a fluctuation in the thread tension, which is generated at the wrap.

Claims (4)

Claims 1. Weft thread monitor for looms, which in the event of broken, loose or not inserted at all weft thread the loom with the help electrical means shut down, characterized in that it one by the flyby of the shooter triggered periodically, arranged in a stationary manner opposite the shooter Has control device, which is based on one of the characteristic form of movement of the intact weft at the time of insertion responds to the derived signal. 2. Weft thread monitor according to claim 1, characterized in that the control device is a heat source for heating a short piece of the filament of the eye that has leaked out of the shooter and an infrared sensitive transducer for sensing the heated piece of thread contains, which are arranged se that the heated piece of thread only when the intact Weft corresponding movement is perceived. 3. Weft thread monitor according to claim 1, characterized in that the control device contains an ion source for generating a surface charge on a short piece of the weft thread emerging from the shooter and an electrical receiver for detecting the charged thread piece, which are arranged so that the charged thread piece only is perceived in the movement corresponding to the intact weft thread. 4. Weft thread monitor according to claim 1, characterized in that the control device contains an optical scanning device which cooperates with an optical system arranged in the shooter, through the focal point of which the intact weft thread moves in the shooter. 5. Sehußfadenwäehter according to claim 4, marked thereby characterized, that the optical system in protecting min- least a collecting device and having a katalioptrisehen reflector, and that the optical Abtastvorriehtung includes a light source, a light receiver and a device for the separation of emitted and reflected bundle . 6. Weft thread monitor according to claim 4, characterized in that the control device contains an evaluation circuit in which the modulation of the scanning beam generated by the thread movement in the shuttle is determined when the thread is intact. 7. Weft thread monitor according to claim 1, characterized in that the control device contains an optical scanning device in the form of a light barrier which is traversed only by the intact thread that has emerged from the shooter. B. Weft thread monitor according to claim 1, characterized in that the control device contains an optical scanning device in the form of a light barrier with a convergent beam which is only traversed by the intact thread that has emerged from the shooter at the apex of the convergent bundle. 9. Weft thread monitor according to claim 7 or 8, characterized in that it has a fan which prevents the broken thread from getting into the effective area of the light barrier. 10. Sehußfadenwäehter according to claim 7, characterized by a pin which is arranged der_so that it prevents the broken weft thread from crossing the light barrier. 11. Weft thread monitor according to claim 7, characterized in that the light barrier consists of a shadow optic which is made up of a light source and a photoelectric cell with a slot or hole-shaped entry aperture . 12. Weft thread monitor according to claim 8, characterized in that a plurality of convergent light beams are generated simultaneously in the light barrier by imaging an illuminated row of apertured diaphragms. 13. Weft thread monitor according to claim 8, characterized in that in the light barrier on the image side, a number of convergent bundles of rays by imaging the weft thread on the entrance opening of the photoelectric cell. forming pinhole row are generated. 14. Weft thread monitor according to claim 7 or 8, characterized in that a pin is attached to the reed below and above each so that the path for the passage of the light beam is released by dividing the warp threads in the rear store position. 15. Weft thread monitor according to claim 1, characterized in that the control device comprises an electrical trigger device triggered periodically by the shooter and a storage device actuated by the trigger device which is designed so that it only passes on a signal if it does not have the intact thread in the trigger interval characterizing signal received cat. 16. Sight thread monitor according to claim 15, characterized in that the trigger device has at least one fixedly mounted solenoid in which a voltage pulse is induced by the fly of a magnet built into the shuttle. 17. Sehußfadenwächter according to claim 16, characterized in that the trigger device has a double solenoid, the solenoids of which are passed by the magnet one after the other and whose one output is connected directly to a coincidence circuit, while the other output is connected to the coincidence circuit via a pulse extender. 18. weft stop motion according to claim 7 or 8, characterized by means mounted in the center of the loading Zichteohranke, a respective left and right thereof for dismantling, installation tes Triggereolerloid, one each connected to the trigger outputs Entkopplungediode, one each with the increases flank and one of the trailing edge Triggeriapulee controlled bistable pulse shaper multivibrator, an AND gate connected to the current flow of the received pulse, which is controlled by the falling-flue multivibrator, a differentiating and limiter network that derives a clock pulse from the pulse supplied by the rising edge multivibrator, and one from the clock pulse and Anticoincidence network fed by the received pulse controlled by the AND gate. 19. Weft thread monitor according to claim 1, characterized in that means are present in the shooter which deform the moving weft thread in such a way that the thread exerts strong deformation forces that depend on the speed and weakly tension on these means, and the control device has an optical one Contains scanning device, the scanning beam is interrupted by the first-mentioned means when the thread is intact before reaching a kata dioptric reflector mounted in the shooter. 2u. Weft thread guard according to claim 19, characterized in that the means deforming the weft thread are designed so that the thread is designed to produce strong and weak speed. stress-dependent deformation forces under relatively high pressure past a small area of a material with a low coefficient of friction, - the angle of wrap being at most 900 . 21. Weft thread monitor according to claim 19 and 20, characterized in that the shooter has means for generating acting on the weft thread, slightly speed-dependent, compared to the deformation forces much larger braking forces die.so designed that the weft thread with relatively low pressure is guided past a large surface of a material with a high coefficient of friction, the angle of wrap being at most 900 . 22. Weft thread monitor according to claim 19, characterized in that the means have only a single movement freedom, whose axis of action can be set optionally such that a more or less strong influence by the normally acting tension forces is added to the tangentially acting deformation forces. 23. Weft thread monitor according to claim 19, characterized in that the means consist of a leaf spring around which the weft thread wraps around in a low-friction guide with a small radius of curvature at an angle of at most 90o. 24. Weft thread monitor according to claim 19, characterized in that the älittel consist of a spring which is wrapped around the weft thread in a low-friction guide with a small radius of curvature at an angle of at most 90o. 25. 5 weft thread monitor according to claim 19, characterized in that the lilittel consist of an optionally elastic lever, which is wrapped by the weft thread in a low-friction guide with a small radius of curvature at an angle of at most 90o, which is pivotably mounted in a cutting bearing, and of more magnetic. Forces is held in its rest position. 26. Weft thread monitor according to claim 19, characterized in that the means consist of a rotatably mounted deflection abutment with a small coefficient of friction, a small radius of curvature and a maximum of 900 angles of wrap, the axis of rotation running through the center of gravity of the rotation system. 27. Weft thread monitor according to one of claims 23-26, characterized in that the means are subjected to externally acting magnetic or spring forces, whereby an additional deformation of the thread is achieved with a small angle of wrap. 28. Weft thread monitor according to claim 19, characterized in that the scanning device has a light source, two photoelectric cells and a wedge-shaped glass prism which is partially transparent on both sides. 29. Weft thread monitor according to claim 28, characterized in that the front side of the prism has 0.20% and the rear side 0.32% reflectivity, and that the outputs of the two photoelectric cells are fed into a coincidence network, with a pulse extender in one channel is switched on. 30. Schußfadenwädnter'nach claim 19, characterized in that for the purpose of scanning the shooter in only one flight direction apart from the actual signal reflector, two closely spaced auxiliary reflectors are attached in the shooter. 31. Weft thread monitor according to claim 30, characterized in that the output of the electro-optical scanning device is a pulse switch and the two outputs of which are fed to a coincidence network, a pulse extender being switched on in one channel of the coincidence network.