Classifications

• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03J—AUXILIARY WEAVING APPARATUS; WEAVERS' TOOLS; SHUTTLES
  • D03J1/00—Auxiliary apparatus combined with or associated with looms
  • D03J1/13—Auxiliary apparatus combined with or associated with looms for leasing warp
• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03J—AUXILIARY WEAVING APPARATUS; WEAVERS' TOOLS; SHUTTLES
  • D03J1/00—Auxiliary apparatus combined with or associated with looms
  • D03J1/14—Apparatus for threading warp stop-motion droppers, healds, or reeds

Definitions

• the invention relates to a device for separating a predetermined number of threads from a thread layer, in which the threads of the thread layer are clamped in at least two places, and a thread can be separated from the thread layer by means of a separating means.
• the invention also relates to a method as described in the preamble of claim 11.
• Dividing or separating threads is a work step that has to be carried out, for example, for the insertion of warp threads into tableware elements of a weaving machine.
• the warp threads are stretched in a frame, where they form a layer of warp threads.
• the individual threads are very close together. Before moving in, they should be separated from the layer, i.e. that they have to be separated from each other.
• the aim here is to provide a predetermined number of threads, in particular a single thread, for handling for subsequent work steps.
• Another application arises when tying warp threads of an old warp thread layer already provided with weft threads to a new warp thread layer.
• warp threads are clamped into a frame and must be separated from the layer by the knotting machine before knotting.
• the foremost thread is separated from a thread layer, for example with a dividing needle.
• the compartment needle is lowered onto the foremost thread of the layer with a movement that is essentially perpendicular to the plane of the thread layer, and this is achieved with a recess of the compartment needle that is adapted to the cross section of the thread. sums up. It cannot be satisfied that the stocking of a large number of different compartment needles is necessary, since the compartment needles have to be matched very precisely to the respective thread size.
• the separation process is not particularly reliable. For this reason, a so-called crosshair is required as a separation aid, especially in connection with filament yarns.
• the crosshairs must be read into the thread layer beforehand, whereby two cords lying transversely to the warp threads between the warp threads are drawn in or woven in. By moving the cross cords back and forth, the foremost thread is separated from the rest and then separated with the section needle.
• Warp threads are neatly divided and stored through the crosshairs, inserting the separating cords means an additional and often very complex operation. Warp threads that are not divided properly lead to interruptions during weaving or even when weaving the warp, and thus to insufficient productivity. This also applies when double thread detection is provided, as is used for example in knotting machines. From FR 698 064 and GB 2 117 419, further methods are known in which - without using a crosshair - the threads are separated from the thread layer solely by a rotating body which has a thread-like profile on the circumference. However, these processes are only suitable for dividing staple yarns or twisted multifilaments. In the case of non-twisted yarns that consist of several filaments, the yarns are only divided into the individual filaments. So a clean compartment is hardly possible anymore.
• the invention is therefore based on the object of proposing a device and a method with which the division of threads from a thread layer can be carried out with as little effort and steps as possible and nevertheless safely, even if the thread layer is difficult to separate Threads, such as untwisted multifilaments.
• this object is achieved according to the invention by a suction means with which a negative pressure can be generated, and by drive means with which the suction means can be relatively moved relative to the thread layer, with a relative approach of the suction means to the thread layer due to the Negative pressure a deflection of at least one thread in the direction of the suction means can be generated.
• the object is also achieved by a method having the features of claim 11.
• Significant advantages of the invention can be seen in that in order to separate a thread from the layer of the clamped threads, neither a crosshair for prior separation, as in the prior art, is absolutely necessary, nor does the separating means have to be used to intervene in the layer. Above all, reaching into the layer or between two threads led to separation errors in previously known generic devices. According to the invention, intervention is not necessary, since the thread to be separated is separated from the layer by a tensile force which is applied to the thread from outside the thread layer. In particular, it is not necessary to reach behind the thread to be separated.
• a “hooking” of the separating member with filaments from one or even more other threads can be excluded, which is why the invention is particularly suitable for separating such threads.
• the solution according to the invention can therefore also be used independently of threads that are critical for separation, such as spun fiber yarns and multifilament yarns of the roughness or fibrousness of the surfaces of the yarns.
• a tension on the thread clamped between clamping points To exert force that has at least one component transverse to the longitudinal extension of the thread, it is also possible in principle to separate any threads from the thread layer.
• the suction means can be provided with a gap through which air is sucked in, the width of which is smaller than, but at most equal to, an extension of a cross-sectional area of the thread in the direction of the gap width. In this way it can be achieved that a sucked-in thread is not drawn into the gap, but closes it. On the one hand, this increases the suction force with which a thread is held. On the other hand, the gap can thereby be essentially closed, as a result of which no further threads of the layer are drawn in.
• the thread to be separated can move from a certain distance Move the suction device closer to the suction device by deflecting it.
• the suction means with the thread still clamped between two points of a frame, guides the latter with its holding section in the suction means away from the thread layer. This facilitates transfer of the thread from the suction means to a handling device that is subsequently used.
• a control of the device according to the invention and a control of the course of the method can advantageously be carried out by a detection device, which for example comprises an image recognition system.
• a detection device which for example comprises an image recognition system. This makes it possible, for example, to recognize when a thread is in the vicinity of the suction means, in order to then regulate a further approach between the suction means and the thread.
• the detection device can also be used to determine whether the thread to be separated is detected by the suction means and carried away. It can also be determined whether a single thread has actually been separated (so-called double thread detection). If the detection device determines that the separation process was not successful, it can cause a control device to repeat the process.
• a control loop can be formed which provides that the separation process is repeated until the detection device actually detects a single thread separated from the suction nozzle. Since only a translational relative movement between the thread layer and the one separating means is required to separate the threads, the separating process can be carried out very quickly, even when the control loop is used.
• a measurement of those applied to the thread could also be carried out with a capacitive or piezoelectric detection device Voltage can be performed.
• a deflection by the suction nozzle increases the thread tension, whereby reaching a predetermined value for a thread tension could represent a criterion for a successful separation of a thread.
• Figure 1 is a perspective view of a first embodiment of a device according to the invention together with a thread layer.
• Figure 2 is a sectional view through a suction nozzle, which is located on the edge of a thread layer.
• FIG. 3 shows the device according to FIG. 1 with a separated thread
• a thread layer 1 which has a plurality of substantially equally long and parallel threads 2, which are clamped at their ends 3, 4 in a suitable holder, not shown.
• Successive threads 2 ideally each have the same distance from one another, but can also be spaced differently without this impairing the functionality of the invention.
• the threads 2 are all in one plane, namely the thread layer plane.
• the reticle 1 contains no cross hairs.
• FIG. 1 also shows a camera 5 arranged above the thread layer plane and one below the thread layer provided light source 6 (for example a light emitting diode), both of which belong to an optical detection device.
• Camera 5 and light source 6 lie on the same optical axis 7, which is aligned at least substantially orthogonally to the thread layer plane.
• a suction means 8 is provided between the camera 5 and the light source 6, next to which a compartment means, such as the compartment pin 9 shown in FIG. 1, is arranged. Both the suction means 8 and the compartment pin are in the detection range of the camera 5.
• Camera 5, light source 6, suction means 8 and compartment pin 9 form a structural unit in a manner not shown, for example by arrangement on a common carrier. These elements can thus be moved parallel to each other to the thread layer level.
• drive means not shown, are also provided.
• the suction means 8 is additionally designed to be movable on the assembly, so that relative movements between the suction means 8 and the camera 5 are possible.
• the camera 8 can have a CMOS sensor with, for example, 640 x 480 pixels.
• the number of active picture elements, ie picture elements whose information is taken into account in the signal processing, can be variable in such sensors. Since fewer image points are required for detailed recordings of the separation process than for overview recordings, and the achievable image frequency increases with a decreasing number of image points, the image frequency can be significantly higher for detailed recordings than for overview recordings. This makes it possible to capture and react to changing situations particularly quickly during the actual separation process by taking detailed pictures.
• the camera has a first interface which is designed as a serial asynchronous interface, for example a standardized LVDS interface (Low Voltage Differential Signaling).
• Control signals such as image size, exposure time, etc.
• image size, exposure time, etc. are transmitted to the camera by a higher-level control device (not shown) via this interface.
• the images recorded by the camera can then be forwarded to a digital signal processor (DSP) via a further LVDS interface of the camera.
• DSP digital signal processor
• Common image evaluation software is available to the digital signal processor, with which individual threads and their position in relation to other threads as well as with respect to the suction means and the compartment pin can be determined.
• the evaluation result of the digital signal processor is in turn fed to the control unit, which controls the movements and functions of the suction means 8 and the compartment pin on this basis.
• FIG. 2 shows a cross section through the suction means 8 designed as a suction nozzle 12 and through threads of the thread layer 1 near the edge.
• the suction means 8 which is constructed symmetrically with respect to the thread layer plane 13, has a conical nozzle section 14 which has two nozzle surfaces 14a, 14b which are inclined in a funnel shape.
• An opening angle ⁇ enclosed by the two nozzle surfaces 14a, 14b can be selected from an angular range of, for example, 30 ° to 130 °, preferably up to 90 °.
• the nozzle section 14 opens into a suction gap 15, which is provided with a constant gap width h. As shown in FIG. 2, the gap width h is smaller than the diameter D of the cross-sectional area of a thread 2.
• the gap height h is approximately half the diameter D.
• a pressure p 1 # prevails in the suction chamber 16, where pi is less than the ambient pressure p 0 .
• a difference between pi and p 0 can be, for example, 0.6 bar.
• a vacuum pump (or vacuum pump), not shown, or an ejector, with which vacuum can be generated, is connected to line 17.
• the assembly with the suction nozzle 12 is brought closer to the foremost thread 2a by a feed movement generated by the drive device until the camera 5 the foremost threads 2, at least the foremost thread 2a , which detects layer 1.
• the feed movement takes place along the arrow 18, which is aligned within the thread layer plane 13 and essentially orthogonal to the longitudinal course of the threads 2. Since a control device knows the distance of a thread detected at the outer edge of the detection range of the camera 5 from the suction nozzle 12, the suction nozzle can now be approximated to the first thread 2a by a predetermined further travel path in the feed direction (arrow 18).
• nozzle 12 to the thread 2a controlled by the control device by means of measurement results from the detection device could also take place.
• the suction nozzle is moved in the feed direction with respect to the now stationary camera. The camera can thus be used to determine the travel distance of the suction means 8 and the remaining distance to the thread 2a. This state is shown in Fig. 1.
• the feed movement and the deflection of the thread 2a have the result that the thread 2 lies with a section in the suction section against the suction gap 15 and closes it, as shown in FIG. 2. Since this increases the pressure difference on both sides of the thread (i.e. between the gap 15 and an area in the nozzle section 14 immediately behind the thread 2a), the holding force with which the thread 2a is held in the suction nozzle 12 also increases.
• the suction nozzle 12 is guided away from the thread layer 1 together with the thread section held by it in the direction opposite the feed direction (arrow 18) (arrow 19).
• the camera 5 which is still stationary and the evaluation unit of the control device in the form of the digital signal processor connected to it, determines whether the suction nozzle 12 has detected a thread 2 and actually only the foremost thread 2a. As soon as a single detected thread is detected by the camera, the backward movement is stopped on the basis of a corresponding signal from the control device. If this cannot be determined, the negative pressure is released, any threads detected are released, a negative pressure is subsequently built up again and the thread detection process described above is repeated until the evaluation unit detects correct thread detection.
• the evaluation unit detects a correctly detected front thread 2a, the compartment pin 9 now sticks into the enlarged insert gap between the foremost thread 2a and the subsequent thread 2b.
• the foremost thread 2a is thereby clearly separated or separated from the thread layer 1 and is available for further processing or handling. In this way, all threads 2 of layer 1 can be separated one after the other.

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Replacing, Conveying, And Pick-Finding For Filamentary Materials (AREA)
• Treatment Of Fiber Materials (AREA)
• Forwarding And Storing Of Filamentary Material (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)

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Applications Claiming Priority (2)

Publications (2)

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Citations (6)

• 2002
  • 2002-04-25 DE DE50207643T patent/DE50207643D1/de not_active Expired - Lifetime
  • 2002-04-25 AT AT02717927T patent/ATE334241T1/de not_active IP Right Cessation
  • 2002-04-25 PT PT02717927T patent/PT1383949E/pt unknown
  • 2002-04-25 KR KR1020027017507A patent/KR100905349B1/ko active IP Right Grant
  • 2002-04-25 WO PCT/CH2002/000230 patent/WO2002088445A2/de active IP Right Grant
  • 2002-04-25 CN CNB028022130A patent/CN1279235C/zh not_active Expired - Lifetime
  • 2002-04-25 EP EP02717927A patent/EP1383949B1/de not_active Expired - Lifetime

Patent Citations (6)

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