EP1483436A2

EP1483436A2 - Pneumatic thread tensioner and thread handling system

Info

Publication number: EP1483436A2
Application number: EP02760248A
Authority: EP
Inventors: Pär JOSEFSSON
Original assignee: Iropa AG
Current assignee: Iropa AG
Priority date: 2002-03-12
Filing date: 2002-07-17
Publication date: 2004-12-08
Anticipated expiration: 2022-07-17
Also published as: US7275291B2; CN100554544C; KR100636075B1; US20050217094A1; KR20040104505A; CN1623017A; JP2005527707A; AU2002325887A1; EP1483436B1; SE0200745D0; AU2002325887A8; WO2003076704A2; DE50208092D1; WO2003076704A3

Abstract

The invention relates to a pneumatic thread tensioner (T) for a gripper shuttle loom or a knitting machine, in which the air-current deflection surface (19) for deflecting the thread (Y, Y1) forms a seamless extension (12) of the inner wall of the linear guide channel, through which the thread runs. The invention also relates to a device (H) for changing the flow rate or the pressure of the air-current along the deflection surface (19) of the pneumatic thread tensioner (T) between at least two different levels, in accordance with the operating cycle of the textile machine.

Description

Pneumatic thread stretcher and thread processing system

The invention relates to a pneumatic thread stretcher and a thread processing system according to the preamble of claim 7.

In the thread processing system according to GB 14 69 533, downstream of a slip delivery device and upstream of a knitting system of a flat knitting machine, the pneumatic thread stretcher is arranged in such a way that the air flow emerging from the blow-out end of its tubular body is opposite to the thread running direction. In the blow-out direction, a cylinder with a cylinder axis oriented transversely to the thread running direction is arranged at a considerable distance in front of the blow-out end of the tubular body, the outer circumference of which affects approximately the extension of the axis of the tubular body. The air stream emerging from the blow-out end along the thread is deflected away on the outer circumference of the cylinder away from the elongated axis of the tubular body, wherein it forms a stretching loop in the thread. The flow rate and the pressure of the air flow are adjustable. The pneumatic thread stretcher works continuously. It is also useful in a loom thread processing system. The continuous operation of the pneumatic thread stretcher does not only result in high air consumption due to the air flow spreading laterally on the cylinder, but the thread can be damaged in its resting phase by the flow dynamics of the air flow. Furthermore, there is a permanent risk that the air stream emerging at the blow-out end flows out in front of the cylinder through the space between the blow-out end and the cylinder, so that the thread in this space can form a false loop, which can easily hang up or move sideways on the cylinder , which can cause the thread to tear when stretched by pulling the textile machine.

In the thread processing system known from US Pat. No. 5,816,296 with a weaving machine, a tube-like structure is arranged in the thread path, through which the thread passes. Two nozzles are arranged in the tubular structure, one of which blows against the direction of travel and the other in the direction of travel. The two nozzles are acted upon by solenoid valves depending on the operating cycle of the weaving machine and / or disconnected from the pressure supply. A pneumatic thread stretcher according to US 6 009 915 A works with two nozzles working at an acute angle to one another in order to stretch a relaxing thread by forming a loop.

The invention has for its object to provide a pneumatic thread stretcher of the type mentioned, which is structurally simple and stretches the thread effectively, has relatively low air consumption, and does not pose a risk to the thread. It is also an object of the invention to provide a thread processing system with at least one pneumatic thread stretcher, in which the thread stretcher operates with a relatively low air consumption and does not pose a hazard to the thread.

The object is achieved according to the invention with the features of claim 1 and the features of claim 7.

Since the air flow deflection surface in the thread stretcher is a seamless and laterally limited extension of the inner wall of the guide channel, essentially the entire energy of the air flow is used to stretch the thread. Portions of the air flow cannot vanish sideways in front of the deflection surface. The result is a relatively laminar flow that optimally exploits the Coanda effect by adhering to the deflection surface and pulling the thread from the tube body axis laterally into the loop and thus stretching the thread if the thread should yield at this point. The lateral limitation of the deflection surface avoids loss of compressed air and acts in the sense of an effective and defined control of the thread when forming the loops.

In the thread processing system, by changing the flow rate or the pressure of the air flow along the deflection surface between at least two different levels and in association with the operating cycle of the textile machine, not only the air consumption is reduced, but especially in the resting phases of the thread, the risk of thread damage due to the flow dynamics of the air flow minimized. At the low level, the mechanical load on the thread is not critical. The high level is assigned to the operating cycle of the textile then set, and only temporarily, if an additional stretching action by the pneumatic thread stretcher is required for proper thread control.

In terms of construction, the air flow deflection surface in the thread stretcher is in one piece with the tubular body. This means that no separate holder for the deflection surface is required.

The extension is expediently designed in the manner of a half pipe, which is delimited on both sides by guide walls, so that the air flow is guided cleanly as soon as it follows the deflection surface, and the thread is also deformed into the stretching loop in a controlled manner.

The side walls can diverge or converge from the airflow deflecting surface or can also run parallel to one another. They should be spaced so far apart that the thread does not contact the side walls when the normal thread path is stretched.

In terms of production technology, the extension is formed from an excess length of the tube body, which is cut open in the longitudinal direction, so that the tube walls bend or open outwards and the entire excess length can be bent away to one side of the tube body axis.

In the communication with the pressure supply, the thread stretcher includes an adjusting element, with which the flow rate or the pressure of the air flow generated along the deflection surface can be switched between at least two different setting values, expediently remote-controlled, so that the thread stretcher only then has a significant stretching effect in the thread generated when this effect is required for thread control. In phases in which no stretching effect is required, for example in a dysentery phase of the thread, work is carried out at the low level, at which the air flow is sufficiently weak and has no harmful effect on the thread. If, in the rest phase of the thread, the air was blown with an undiminished flow rate or pressure, it would not be possible to avoid the thread dancing in the flow and being dissolved by the flow or even striking contact with the pipe body or the deflection surface and damage.

In the thread processing system, the communication of the thread stretcher with the compressed air supply contains at least one adjusting element with an electric actuator, preferably a solenoid valve, in order to switch between at least two different levels of the flow rate or the pressure. The operation of the thread stretcher can be controlled in this way depending on the operating cycle of the textile machine. The signals which cause the changeover between the levels are transmitted via a signal connection, either from a control device of the textile machine or the thread delivery device, or from a communication system into which the textile machine and / or the thread delivery device is (are) integrated. In the case of a communication system, e.g. a data bus system (CAN or the like), a control box is often provided, from which different functional units are controlled or monitored. The signals for actuating the actuator of the thread stretcher can preferably be derived from this central control box, e.g. by means of a message translating processor.

If the textile machine is used to produce a patterned product, e.g. in a weaving machine with weft threads of different qualities or colors in several thread channels, or in a knitting machine with several knitting systems, then it is advisable to design the device so that it adjusts the thread stretcher depending on the pattern between the Levels. This means that, for example, only the thread stretcher of an activated thread channel operates at the high flow rate or pressure level, while the thread stretchers in the non-activated thread channels are passivated or only operate at the low level. The thread stretcher of an activated thread channel can be switched between the high and low levels by the device, adapted to the operating cycle of the textile machine in this thread channel. The high level is set in each case, for example, if additional thread stretching is to be used to prevent the thread from being too loosely at times, or to prevent a component of the text Assist the tilmaschine by increased thread tension, which temporarily needs a stronger pull in the thread to function properly.

In a thread processing system with a rapier weaving machine, the device can be designed in such a way that the strong flow rate or the high pressure in the thread stretcher is temporarily set in each case during an insertion process when the bringer gripper takes over the thread tip and / or transfers the thread tip to the take-up rapier, and / or the entry process is ended. In the other phases of the entry process, on the other hand, the low level is set because then a significant pull in the thread is safely translated. The changeover is carried out by the device by means of signals which represent certain angles or ranges of rotation of the main shaft of the rapier weaving machine in the aforementioned operational phases.

In a thread processing system with a rapier weaving machine with several thread channels that can be activated alternately depending on the weaving pattern, a pneumatic thread stretcher is provided in each thread channel. The device is designed in such a way that it switches the flow rate or the pressure to the low level when the thread channel is not activated with this thread stretcher and the thread e.g. remains in a resting phase. This is preferably done using signals, e.g. derived from the control of a thread selector, which represent the at least one non-activated thread channel.

Optimal results are achieved with the controlled pneumatic thread stretcher if the thread stretcher downstream of the thread delivery device is functionally combined in the thread travel path with a stationary thread brake ring, preferably a soft, bristle brake ring, which contacts a pull-off end of a stationary storage drum in the thread delivery device. The bristle brake ring generates a relatively constant, low basic tension in the thread, on which the thread stretcher superimposes an additional tensile load, at all at the low level or not at all significantly, but significantly at the high level. The bristle brake ring also prevents the thread from possibly extending upstream of the loop formed the storage drum can relax, which would disturb the thread turns held there.

Embodiments of the subject matter of the invention are explained with reference to the drawing. Show it:

1 shows a schematic overall view of a thread processing system, with several detailed variants being indicated,

Fig. 2 is a partial longitudinal section of a pneumatic thread stretcher, and

Fig. 3 is a view of the thread stretcher of Fig. 2 from the left side.

A thread processing system S in Fig. 1 includes i.a. a textile machine R, for example a rapier weaving machine or a knitting machine, at least one thread delivery device F, and a pneumatic, controlled thread stretcher T in the thread travel path downstream of the thread delivery device.

The textile machine R explained using the example of a rapier weaving machine has a shed D and drivable bring and take grippers B, N for inserting at least one thread Y, Y1 from at least one thread channel. The gripper B takes over the thread tip in an entry and thread selector device 2 and pulls the thread into the middle of the shed D, where it transfers the thread tip in an area 1 to the take-up gripper N, which then pulls the thread entirely through the shed and that Entry ended.

The thread delivery device F has a housing 3 with a stationary storage drum 4, to which the thread Y is fed in successive turns by means of a winding element 5. A trigger eyelet 7 is positioned on a housing bracket 6. Furthermore, a thread brake A in the form of a, preferably soft, bristle brake ring 8 is held on the housing arm 6 and contacts a withdrawal end 9 of the storage drum 4 from the outside and counter to the withdrawal direction of the thread. The pneumatic thread stretcher T has a housing 10 and a tubular body 11 which extends in the direction of the thread travel path and which has an extension 12 bent laterally in a curved manner opposite to the thread running direction. The detailed design of the thread stretcher T will be explained later with reference to FIGS. 2 and 3. A connector 13 is provided on the housing 10 and is or can be connected to a pressure supply P for compressed air. A device with a flow rate or pressure setting element 14, for example a solenoid valve with an electric actuator M (for example a switching magnet or a proportional magnet), serves to switch the flow rate or the pressure between at least two different setting values. The changeover is carried out remotely by means of the device H by signals which come via a signal connection 15 either from a control device C of the thread delivery device or a control device CU of the textile machine R or a communication system K. In the case of a communication system K, in which the thread delivery device F and the textile machine R are incorporated, a central control box CB can be provided, in which the signals for the actuator M are generated from messages in the communication system K (for example a CAN bus system). The high level and the low level are nominally adjustable. The low level is expediently chosen so that the thread is hardly or not at all loaded. The high level is set so that the thread is subjected to an appropriate tensile load by an air stream and, along the extension 12, is deflected from the straight thread path into a lateral loop L and is thereby stretched from the downstream.

In the case of the rapier weaving machine, it is expedient to temporarily set the high flow rate or pressure level at that very moment, e.g. as a function of the tapped angle of rotation of the main shaft of the rapier weaving machine when the rapier gripper B takes over the thread tip and / or as soon as the rapier gripper B transfers the thread tip to the slave rapier N and / or finally at the end of the entry process. In between, the thread stretcher T operates at the low level.

If, as is often the case, the rapier weaving machine R works with several thread channels (threads Y, Y1), then each thread channel is a pneumatic thread assigned to the stretcher B. In addition, the device H, which is responsible for controlling the thread stretcher T, is designed such that it sets the thread stretcher of a non-activated thread channel to the low flow rate or pressure level. The device H can be assigned to all thread stretchers together, or a corresponding device H is provided for each thread stretcher.

In an analogous manner, a knitting machine is equipped in its thread channels with pneumatic thread stretchers T of the type shown here, and a device H is provided with which the thread stretchers are controlled depending on the operating cycle of the knitting machine between different flow rate and pressure levels.

According to FIG. 2, the straight tubular body 11 defines an air flow and thread guide channel 20. The air flow is generated from the connection 13 against the thread running direction via a nozzle device, which is accommodated in the housing 10 and is not shown in detail. The extension 12 forms an air flow deflecting surface 19 which is bent laterally convexly away from the imaginary extension of the tubular body axis and is delimited on both sides by guide walls 17. This design is easily produced, for example, by manufacturing the tubular body 11 with an excess length corresponding to the extension 12 and then cutting the excess length lengthwise up to a shoulder 16. Then the tube walls are bent apart to form the guide walls 17 and the extension 12 is brought into the curved shape. The inner edges of the guide walls 17 can have inside phases 18 or be rounded in order not to become dangerous for the thread. The guide walls 17 of the extension 12, which is U-shaped in its basic form, can diverge or converge starting from the deflection surface 19 or can also run parallel. The thread stretcher T works with the so-called Coanda effect. This means that the relatively laminar air flow directed along the guide channel 20 adheres to the deflecting surface 19 and follows it, thereby deforming and stretching the thread (as indicated in FIG. 1) into the loop L, provided the thread is currently under low internal stress , In Fig. 3 it is indicated that the distance between the guide walls 17 gradually widened. Alternatively, the tubular body 11 with its extension 12 could also be a plastic molded part, for example an injection molded part.

The flow rate and pressure setting element 14 shown in FIG. 1 is expediently a quickly responding pneumatic solenoid valve. The nozzle device in the housing 10 is expediently a so-called ejector nozzle, which directs the air flow to the left in FIGS. 1 and 2, and can also suck in air from the right end of the housing 10. In the thread path downstream of the thread stretcher, further devices that monitor or control the thread path can be provided, as is conventional standard in rapier weaving machines.

Claims

claims

1. Pneumatic thread stretcher (T), in particular for a rapier weaving machine (R) or a knitting machine, with an essentially straight tubular body (11) which has an end communicating with a compressed air supply (P) and has a blowout end facing away from it and a thread and Defined air flow guide channel (20), and with an air flow deflecting surface (19) which is arranged in front of the blow-out end and is approximately adjacent to an imaginary extension of the tubular body axis and is curved in the blow-out direction from the blow-out end and is bent away from the tubular body axis, characterized in that the Airflow deflecting surface (19) is a seamless, laterally limited extension of the inner wall (20) of the guide channel.

2. Pneumatic thread stretcher according to claim 1, characterized in that the air flow deflecting surface (19) with the tubular body (11) is in one piece.

3. Pneumatic thread stretcher according to claim 1 or 2, characterized in that the air flow deflecting surface (19) is arranged in the manner of a half pipe extension (12) and is delimited on both sides by guide walls (17).

4. Pneumatic thread stretcher according to claim 1, characterized in that the cross section of the extension (12) is approximately U-shaped, with side walls (17) which diverge or converge from the air flow guide surface (19) or run parallel.

5. Pneumatic thread stretcher according to claim 1, characterized in that the extension (12) is formed from an excess length of the tubular body (11) by cutting, bending the tube walls outwards and bending the excess length to one side of the tube body axis.

6. Pneumatic thread stretcher according to claim 1, characterized in that in communication with the pressure supply (P) at least one, preferably remotely controllable, adjusting element (14, M) is included, with which the flow rate or the pressure of an air flow generated along the air flow deflection surface (19) is adjustable and / or can be switched between at least two different setting values.

7. Thread processing system (S), with a thread consuming textile machine (R); in particular a rapier weaving machine or a knitting machine, at least one thread delivery device (F), and at least one pneumatic thread stretcher (T) arranged downstream of the thread delivery device in the thread travel path, which has a guide channel communicating with a compressed air supply (P) and a blow-out end pointing against the thread running direction An air flow deflecting surface (19) is arranged in the blow-out direction, along which the thread can be deflected with an air flow from the straight path into a loop, characterized in that a device (H) for changing the flow rate or the pressure of the air flow along the deflecting surface (19) is provided between at least two different levels and in association with the operating cycle of the textile machine (R).

8. Thread processing system according to claim 7, characterized in that in communication with the compressed air supply (P) at least one flow rate or pressure adjusting element (14) with an electric actuator (M), preferably a solenoid valve, is provided, and that between the actuator (M) and a control device (CU) of the textile machine (R) and / or the thread delivery device (F) and / or a communication system (K) of the thread processing system (S), preferably with a central control box (CB) within the communication system, a signal connection (15) is provided.

9. Thread processing system according to claim 8, characterized by a device (H) which can be converted depending on the pattern of the product manufactured in the textile machine (R) and which is associated with pneumatic thread stretchers (T) in several thread channels together.

10. Thread processing system according to claim 8, characterized by a depending on the operation cycle of the textile machine in a thread channel convertible device (H), which is assigned to a pneumatic thread stretcher (T) of a thread channel.

11. Thread processing system according to at least one of claims 7 to 10, characterized in that in a thread processing system (S) with a rapier weaving machine (R) with the device (H) the flow rate or the pressure in each case when the thread is taken over by the rapier gripper (B) and / or when transferring the thread from the rapier gripper (B) to the slave gripper (N) and / or at the entry end, it can be converted to the high level, preferably by means of signals which indicate the angle of rotation of the rapier weaving machine when the thread is taken over and / or the thread is transferred and / or when the entry ends represent.

12. Thread processing system according to at least one of claims 7 to 10, characterized in that in a thread processing system (S) with a rapier weaving machine (R) with a plurality of thread channels that can be activated alternately depending on the weaving pattern, a pneumatic thread stretcher (T) is assigned to each thread channel, and that with the Device (H) the flow rate or the pressure for the pneumatic thread stretcher (T) of a non-activated thread channel can be changed to the low level, preferably by means of signals which represent at least one non-activated thread channel (Y, Y1).

13. Thread processing system according to at least one of claims 7 to 12, characterized in that the pneumatic and controlled thread stretcher (T) is functionally combined with a stationary thread brake ring, preferably a soft bristle brake ring (8), which has a withdrawal end in the thread delivery device (F). 9) contacted a stationary storage drum (4).