EP2027316B1 - Method for clamping a weft thread in a jet weaving machine, in particular air-jet weaving machine, clamping device and jet weaving machine - Google Patents

Abstract

In a method for clamping a weft thread (3) in a jet loom in which the thread is blown into a weaving region using transporting fluid through main blast nozzle(s) (1) with a mixing tube (2), where the thread is temporarily clamped during passage through the nozzle and tube using a movable clamping member, moved by an actuator outside the tube between thread clamping and release (non-clamping) positions, the clamping force of the member in clamping position is magnetically reinforced. Independent claims are included for: (1) a corresponding clamping device for carrying out the process, having at least one retaining magnet (11) for magnetically reinforcing the clamping force of the clamping member in the clamping position; and (2) a corresponding jet loom incorporating the clamping device.

Description

The invention relates to a method for clamping a weft thread in a jet loom, in particular air jet loom, according to the preamble of claim 1. The invention further relates to a clamping device on a weaving machine, in particular air jet machine according to the preamble of claim 11. Finally, the invention also relates to a jet loom according to the The preamble of claim 22.

The prior art according to the preambles of claims 1, 11 and 22 is by the DE 10 2004 036 996 B3 played. Thereafter, a device for entering a weft thread is provided in the shed on a jet loom, which consists of a block of Hauptblasdüsen with connected mixing tubes. In each mixing tube, a clamping device is provided, by means of which the weft thread located in the mixing tube is held straight in alignment before it is introduced into the shed. Each of these clamping devices has an actuator located outside the mixing tube, which can be pneumatically or piezoelectrically actuated and deformed. Characterized a connected to the actuator clamping member is placed in a tilting or pivoting movement. The clamping member engages in the mixing tube and clamps with its free end the weft thread against an abutment located on the mixing tube. Preferably, the embodiment of the actuator in the form of an elastomeric bellows, which is directly connected to the clamping member. By different pneumatic loading of the actuator can be controlled and deformed, with a supply line is provided for a separate pneumatic control fluid.

In addition to the different pressurization and the inherent elasticity of the formed as an elastomer bellows actuator, a spring or a bending elastic holding element can influence the respective position of the clamping member. Finally, the clamping member itself can be elastically deformed.

The known clamping devices according to the DE 10 2004 036 996 B3 are already constructed of modular units of two clamping devices; several can do this Module units are combined into a block. Nevertheless, relatively little space is available for the individual clamping unit. However, the holding force of a pneumatically actuated holding device is dependent on its size. If the dimensions must be small, the holding power is limited. The same applies to a hydraulic or piezoelectric actuation of the actuators. In addition, in the case of pneumatic control, the compressibility of the controlling air flows is still disturbing. This leads to a delayed Ans prechverhalten the clamping device. It has been found that the clamping member is set in the transition from its clamping position to the release position and vice versa in vibrations, so that particularly fine weft threads are no longer reliably clamped timely. The delayed response of the clamping devices can already lead to disturbances in the weaving process at today's speeds of up to 1000 U / min in modern weaving machines.

From the JP 2000 119 936 A is another pneumatically actuated clamping device of holding weft yarns on jet looms known. The clamping member is located there similar to a non-return valve at the outlet of the mixing tube, where it is pivotally mounted on a hinge located outside the mixing tube and is retracted by a tension spring also located outside in the outlet opening of the mixing tube. In this case, a weft thread is clamped against a shoulder which forms part of the outlet opening. The blowing air flow of the main blowing nozzle which introduces the weft threads is intended to open the clamping member against the action of the spring and thereby release the clamped weft thread. In this known clamping device, an exact, fast-running and precisely controllable transition from the clamping position into the release position can not be expected because the control of the clamping member inseparably linked to the transport of the weft thread.

The invention has for its object to provide a method and a clamping device of the initially mentioned type with which in a simple, compact design, a reliable holding power can be achieved in conjunction with an accurate response, so that a nearly trouble-free weaving operation even at high speeds the weaving machine is possible.

The solution of this problem is inventively achieved by the totality of the features of claim 1 and in terms of the clamping device according to the invention by the totality of the features of claim 11 in terms of the method. Claim 22 is directed to a jet loom having the clamping device according to the invention.

According to the invention thus an amplification of the clamping force of the movable clamping member is achieved by an additional magnetic force. Since the holding and clamping force is applied essentially by the magnetic force, the components for operating the clamping device can be dimensioned smaller despite safe operation. It is thus a particularly compact design possible, so that the main blowing nozzles and mixing tubes can be arranged advantageously and as straight as possible weft yarn guide is guaranteed up to the weft insertion channel of the reed. The amount of reinforcing magnetic force is advantageously adapted to the properties of the weft thread, so that an additional clamping is ensured without significantly affecting the quality of the weft thread at the nip.

According to a first development of the method, the magnetic reinforcement is designed such that the release of the movable clamping member from its clamping position initially inhibited, but its approach to the clamping position is accelerated.

In a further advantageous embodiment of the method according to the invention, the holding force of the movable clamping member is magnetically reinforced in its release position. If further measures are taken to the fact that the release of the clamping member initially inhibited from its release position, but its approach to the release position is accelerated, so that overall the dynamic behavior of the clamping member in the mixing tube is influenced very beneficial.

Namely, the magnetic force acts on the clamping member in the first end position until the actuating force originating from the actuator is built up on the clamping member, which is larger than the attracting magnetic force. If this point is reached, then the clamping member goes almost abruptly in the second end position. As well When approaching the respective second end position, an acceleration is achieved by the attractive magnetic force.

Both effects together reduce the switching time required to move the clamping member from the release position to the clamping position and vice versa. The dynamics of the clamping device is thus increased. While in a purely pneumatically operated clamping device, the time behavior of the clamping member qualitatively corresponds approximately to a cosine curve, succeeds by the reinforcing magnetic forces, a temporal compression of this process in the direction of the ideal vertical. It was found that the susceptibility of the clamping member to reverberation after a position change was largely reduced. As a result, especially thin weft threads of up to 0.02 mm can be reliably clamped.

The method may be performed by actuating the actuator hydraulically or piezoelectrically. However, particularly preferred is the control of the actuator by means of a separate pneumatically acting control fluid.

The magnetic reinforcement in the clamping position and / or the release position of the clamping member can be made permanently magnetic in a particularly simple manner.

For certain applications, according to a further preferred embodiment of the method, the permanent magnetic amplification is temporarily canceled by a controlled electromagnet. In this way, z. B. reduces the release force for releasing the clamping member controlled from its end positions or canceled and operated the clamping device with a further lower pressure.

Particularly versatile control options for the method according to the invention result if, according to a further advantageous embodiment, the magnetic amplification is generated by at least one electromagnet. The control of the solenoid (s) is then incorporated into the loom control. In this way, z. B. the clamping force can be adjusted during operation to changed yarn properties or operating conditions. If, for example, a sensitive weft yarn is processed, then the magnetic force the electromagnet and thus the clamping force of the clamping member are set to a lower value, and damage to the weft yarn at the nip are avoided. Robust yarns with a smooth surface can be processed with a high clamping force to ensure that the yarns are held securely despite the smooth surface. In addition, the temporal occurrence of the magnetic force to various operating conditions such as different speeds of the loom can be adjusted.

The invention made possible by the particularly compact design of the associated clamping device makes it possible to make the magnetic reinforcement of the clamping member at each point of Hauptblasdüse and mixing tube. A particularly advantageous possibility, however, is that the weft thread is clamped in the mixing tube, as that of the aforementioned DE 10 2004 036 996 B3 is known.

For the clamping device according to the invention according to claim 11, the same advantages apply, as they have already been indicated for the process.

Also for the inventive, specified in claim 11 clamping device is provided as an advantageous development that the magnetic reinforcement is carried out by at least one holding magnet in cooperation with the clamping member not only in the clamping position, but also in the release position of the clamping member.

For constructive design of the clamping device according to the invention are basically all constructions in question, already in the DE 10 2004 036 996 B3 are listed. However, the embodiment is particularly preferred with a pneumatically actuated actuator, which is designed as Elastomer bellows, which is pneumatically controlled and deformed by overpressure, pressure equalization with respect to the environment or negative pressure and is deformed with the clamping member such that the pneumatic deformation of the elastomer bellows Tilting or pivoting movement of the clamping member for the transition from the clamping position to the release position or vice versa causes. In this case, advantageously, the clamping member may be attached directly to the elastomer bellows. By the actuator formed as Elastomer bellows is deformed or deformed by air as the actuating means, resulting in the tilting movement of the clamping member. Here is the Tilting movement when releasing the clamping member from the clamping position or the release position inhibited by the magnetic force and accelerated when approaching the clamping member to the respective opposite position by the magnetic force.

In an actuator in the form of an elastomeric bellows, the reinforcing magnetic force is particularly advantageous because it not only prevents delays caused by the compressibility of the air. In addition, delays are avoided, which are caused by the resistance with which the elastomer bellows opposes in its deformation of the pneumatic actuating force. In addition, such an elastomer bellows will be deformed at least in one end position and therefore constantly oppose the clamping or holding force in this end position an opposing force; because the elastomer bellows strives to return to its undeformed initial shape. The installation of the holding magnets causes the clamping member is held securely in one of the end positions even in the unpressurized state. This ensures, for example, in the release position that the clamping member does not hinder the free passage through the Hauptblasdüse and the mixing tube by being always held by the magnetic force outside the conveying air flow.

Further embodiments are contained in the other back-related, directed to the clamping device claims. Hereby, further advantages are achieved.

If the clamping member is arranged at a position of the mixing tube and the actuator is located outside the mixing tube, so there is a compact design, in which on the one hand the main blowing nozzles and the clamping devices can be combined in blocks. In the structural design in detail while in the DE 10 2004 036 996 B3 already described detailed solutions are taken advantage of.

For example, the subdivision of the mixing tube in a longer initial section and a much shorter end portion is not just an emergency solution that will allow the engagement of the clamping member in the mixing tube. The significantly shorter end portion of the mixing tube causes, above all, that the free end of the Weft thread after cutting the registered weft thread section can not collide with the clamping device and therefore does not strike back. By dividing the mixing tube thus takes place a decoupling of the clamping device from the thread end.

The arrangement of two clamping devices each with directly adjacent mixing tubes to a module unit in a first plane not only brings the advantage of compact design, but also makes it possible that at least one holding magnet can be used together for each two clamping devices; because those from the DE 10 2004 036 996 B3 known and adopted module unit causes the beginning and end portions of the mixing tube closely adjacent and mirror images of each other. The actuators are provided on the outside of the mixing pipe sections; therefore, a holding magnet located between the mixing tube sections of both clamping devices may optionally be effective for both clamping devices.

• Fig. 1 zeigt eine Vorrichtung zum Einbringen von vier Schussfäden, die nach dem erfindungsgemäßen Verfahren arbeitet und erfindungsgemäß ausgebildete Klemmeinrichtungen enthält.
• Fig. 2 stellt eine Moduleinheit dar, zu der zwei erfindungsgemäße Klemmeinrichtungen zusammengefasst sind.
• Fig. 3 erläutert die Funktion der erfindungsgemäßen Klemmeinrichtung, wobei gemäß Fig. 3a ihre Freigabestellung und gemäß Fig. 3b ihre Klemmstellung dargestellt ist.

The invention will be explained in more detail in an embodiment with reference to the figures. In the drawings, the following is shown:

• Fig. 1 shows a device for introducing four weft threads, which operates according to the inventive method and includes inventively designed clamping devices.
• Fig. 2 represents a modular unit to which two clamping devices according to the invention are summarized.
• Fig. 3 explains the function of the clamping device according to the invention, wherein according to Fig. 3a their release order and according to Fig. 3b its clamping position is shown.

Fig. 1 shows by way of example of a jet loom, a block 17 with four main blowing nozzles 1, to which the mixing tubes 2 connect. Via the connections 13, the main blowing nozzles 1 are supplied with compressed air, which serves to introduce the weft threads 3. The illustrated example allows weaving with four different colors or four different materials of weft yarns 3. The weft yarns 3 through the main blowing nozzles 1 and through the mixing tubes 2 therethrough not shown weft insertion channel of a reed and thus supplied to the shed. The mixing tube 2 is divided into a longer initial section 2.1 and a comparatively shorter end section 2.2. The separation point between the beginning and the end section 2.1, 2.2 is located within the clamping devices, of which in Fig. 1 a common, four clamping devices comprehensive module unit 18 can be seen.

After leaving the end section 2.2 of the associated mixing tube 2, the relevant weft thread 3 passes into the shed, is struck by the reed at the binding point and cut off by a scissors located between the end section 2.2 and the fabric edge. Beforehand, however, the weft thread 3 is clamped in the mixing tube 2 by its associated clamping device located in the modular unit 18, so that it does not spring back into the mixing tube 2.

The block 17 and the module unit 18 are mounted on a common base plate 4, which serves for attachment to the sley, not shown, of the jet loom. Denoted by 11 and 12 are holding magnets which will be explained later; the same applies to the schematically indicated pumps 15 and the valve 16.

In Fig. 2 a single modular unit 18 is shown spatially and enlarged. In this case, two clamping devices 5 are mounted one above the other and close to each other in a frame-like carrier 14. The frame-like support 14 causes the assembly of the mixing tubes 2 is additionally stiffened with the clamping devices 5 in the end region of the mixing tubes 2. The clamping devices 5 are arranged with closely adjacent end portions 2.2 of the mixing tube 2, wherein the associated actuators 6 are outside. The clamping devices 5 also have clamping members 7, which can perform a tilting or pivoting movement and thereby dive into engagement openings 8. These separate the initial sections 2.1 of the mixing tubes 2 from their end sections 2.2. With 11 and 12, the already mentioned holding magnets are again referred to. The basic structure of the clamping devices 5 goes with all the details and in different variants of the DE 10 2004 036 996 B3 the applicant. The embodiments shown there are all for the present invention with magnetic amplification of Holding force suitable. An exemplary embodiment thereof will be described below Fig. 3 out.

Fig. 3a shows a clamping device 5 according to the invention in the release position of the clamping member 7, in which the weft thread 3 is not clamped. Outside the beginning section 2.1 of the mixing tube 2 there is an actuator 6 which is designed as an elastomer bellows with a chamber 10. The chamber 10 is connected via a supply line 20 to the valve 16, which is a pneumatic valve in the present example. The unillustrated control unit of the weaving machine controls the electromagnetically operable valve 16 and thereby can pressurize the chamber 10 of the actuator 6 with air, which is under pressure or is pressureless to the environment. With the actuator, the clamping member .7 is connected, which is designed as a lever with a long lever arm 7.1 and an angled short lever arm 7.2. The clamping member 7 is inserted into a slot which is formed in the elastically deformable actuator 6. The angled short lever arm 7.2 is opposite to an engagement opening 8, which separates the mixing tube 2 in an initial section 2.1 and an end section 2.2. Beginning section 2.1 and end section 2.2 are connected to each other by an abutment 9. The clamping member consists of a ferromagnetic material. The clamping device 5 also has a stop member 19, which may be formed on the frame-like carrier 14.

In the abutment 9, a first holding magnet 11 and in the stop member 19, a second holding magnet 12 is inserted, for. B. poured. In the release position according to Fig. 3a the chamber 10 is depressurized to the environment. The formed as an elastomer bellows actuator 6 is therefore in its relaxed state in which the associated clamping member 7 is parallel to the mixing tube 2 and the weft thread 3 is not clamped. In addition, the clamping member 7 is held by the second holding magnet 12 in the release position.

In Fig. 3b the state is shown in which via the valve 16 and the supply line 20, the chamber 16 of the actuator 6 is charged with air under elevated pressure. As a result, the actuator 6, which is designed as Elastomerbalg, inflated and deformed. The clamping member 7 connected to the actuator 6 follows the deformation and therefore causes a tilting or pivoting movement from, wherein it dives with its angled short lever arm 7.2 in the engagement opening 8 and comes to the abutment 9 in the region of the first holding magnet 11 to the plant. The clamping member 7 presses thereby the weft thread 3 to the abutment 9 with the first holding magnet 11 and holds the weft thread 3 by clamping. The holding force of the first holding magnet 11 thus amplifies the clamping force exerted by the pneumatically deformed actuator via the clamping member. The short end section 2.2 of the mixing tube 2 has mainly the function of preventing the cut end of the weft thread 3 from colliding with the clamping device 5. For each weft thread 3 and thus for each Hauptblasdüse 1 and each clamping device 5, a separate valve 16 is provided. The control of the individual valves 16 takes place depending on which weft thread just has to be entered.

If two of the in Fig. 3 shown clamping devices 5 to a module unit 18 according to Fig. 2 are summarized, there is the possibility, at the location of two first holding magnet 11 to provide a single, which holds the clamping member 7 amplified in its clamping position for both clamping devices 5.

Claims (22)

1. A method for clamping a weft thread (3) in a jet weaving machine, in particular an air jet weaving machine, wherein a weft thread (3) is injected by means of a transport fluid through at least one main blowing nozzle (1) with a mixing tube (2) into a shed, and on its way through the main blowing nozzle (1) and the mixing tube (2), is temporarily clamped by a movable clamping element (7), the movable clamping element (7) being brought by driving an actuator (6) arranged outside the mixing tube (2) selectively into a clamping position or into a release position, in which the weft thread is not clamped, and being maintained in the respective position, characterized in that
   the clamping force of the movable clamping element (7) in the clamping position thereof is magnetically reinforced.
2. The method according to claim 1, characterized in that the magnetic reinforcement is realized so that the release of the movable clamping element (7) from the clamping position thereof is first inhibited, but the approach thereof to clamping position is accelerated.
3. The method according to claim 1 or 2, characterized in that the holding force of the movable clamping element (7) is magnetically reinforced even in the release position thereof.
4. The method according to claim 3, characterized in that the magnetic reinforcement is realized so that the release of the movable clamping element (7) from the release position thereof is first inhibited, but the approach thereof to the release position is accelerated.
5. The method according to any of claims 1 to 4, characterized in that the actuator (6) is controlled pneumatically, hydraulically or piezoelectrically, or controlled pneumatically by means of a separate control fluid.
6. The method according to any of the preceding claims, characterized in that the magnetic reinforcement in the clamping position and/or the release position of the clamping element (7) is done by means of a permanent magnet.
7. The method according to claim 6, characterized in that the permanent magnet reinforcement is temporarily cancelled by a controlled solenoid.
8. The method according to any of claims 1 to 5, characterized in that the magnetic reinforcement is generated by at least one solenoid (11, 12).
9. The method according to claim 8, characterized in that the solenoid (11, 12) is controlled by the controller of the jet weaving machine.
10. The method according to any of claims 1 to 9, characterized in that the weft thread (3) is clamped in the mixing tube (2).
11. A clamping device on a jet weaving machine, in particular an air jet weaving machine, having at least one main blowing nozzle (1) with a mixing tube (2) for picking a weft thread (3) in a shed by means of a transport fluid ejected by the main blowing nozzle (1), with an actuator (6) arranged outside the mixing tube (2), and a movable clamping element (7), which by driving the actuator (6) is brought selectively into a clamping position, in which the weft thread (3) is clamped at a point of the path of the main blowing nozzle (1) and the mixing tube (2), or into a release position, in which the weft thread (3) is not clamped, and is maintained in the respective position, for implementing the method according to any of claims 1 to 10, characterized in that the clamping device (5) has at least one holding magnet (11), and the clamping element (7) is made ferromagnetically at least in some areas, namely in an arrangement such that the clamping force of the clamping element (7) in the clamping position thereof is magnetically reinforced by the effect of the holding magnet (11).
12. The clamping device according to claim 11, characterized in that at least one further holding magnet (12) is provided for cooperating with the clamping element (7) in the release position thereof in terms of a reinforced holding effect.
13. The clamping device according to claim 11 or 12, with a pneumatically controlled actuator, characterized in that the actuator (6) is made as an elastomeric bellows, which can be deformed by means of a pneumatic control fluid via positive pressure, pressure compensation with respect to the environment, or negative pressure, and is operatively connected to the clamping element (7) so that the pneumatic deformation of the elastomeric bellows causes a tilting movement of the clamping element (7) for the transition from the clamping position into the release position or vice versa.
14. The clamping device according to claim 13, characterized in that the clamping element (7) is fastened to the elastomeric bellows.
15. The clamping device according to claim 11 or 12, having a hydraulically controlled actuator, characterized in that for actuating thereof, a hydraulic fluid is supplied and discharged via at least one pump (15) and control valves (16).
16. The clamping device according to any of claims 11 to 15, characterized in that the clamping element (7) is arranged at a location of the mixing tube (2), and the actuator (6) is situated outside the mixing tube (2).
17. The clamping device according to claim 16, characterized in that the clamping element (7) is made as an angled lever with a long lever arm (7.1) and a short lever arm (7.2), wherein the long lever arm (7.1) is extending in the length direction of the mixing tube (2), and the short lever arm (7.2) for moving towards the clamping position plunges into an engagement opening (8) of the mixing tube (2) and puts the weft thread, by clamping the same, against an abutment (9), on which the holding magnet (11) is located, which reinforces the clamping force.
18. The clamping device according to claim 17, characterized in that the engagement opening (8) of the mixing tube (2) divides the latter into a longer first section (2.1) and a substantially shorter ending section (2.2), which is axially aligned with the first section (2.1), and the end thereof forming the outlet of the mixing tube (2), and in that the abutment (9) has a contact surface of increased frictional effect connecting the ending section (2.2) to the first section (2.1) of the mixing tube (2) and closing the engagement opening (8) in a substantially single-sided way.
19. The clamping device according to any of claims 11 to 18, characterized in that pairs of two clamping devices (5) with mixing tubes (2) located directly adjacent to each other are combined into a modular unit (18), both mixing tubes (2) being located in a plane in a mirror-image arrangement, with the actuators (6) being oriented outwards.
20. The clamping device according to claim 19, characterized by the parallel arrangement of up to four modular units (18), vertically to the plane of the modular unit (18), so that a block of up to eight mixing tubes (2) and actuators (6) is formed.
21. The clamping device according to claim 19 or 20, characterized in that both mixing tubes (2) of a modular unit (18) are assigned a common holding magnet (11).
22. A jet weaving machine, in particular an air jet weaving machine, having at least one main blowing nozzle (1) with a mixing tube (2) for picking a weft thread (3) in a shed by means of a transport fluid ejected by the main blowing nozzle (1), wherein the clamping device is provided with an actuator (6) arranged outside the mixing tube (2) and a movable clamping element (7), which by driving the actuator (6) is selectively brought into a clamping position, in which the weft thread (3) is clamped at a location of the mixing tube (2), or into a release position, in which the weft thread (3) is not clamped, and is maintained in the respective position, characterized by the arrangement of a clamping device according to any of claims 11 to 21.

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