EP1082478B1 - Gripper and weft insertion device for a rapier loom - Google Patents

Description

The invention relates to a gripper for a Rapier weaving machine according to the preamble of the claim 1 and a weft insertion device with a gripper.

To insert a weft thread, either a gripper is used to guide the weft thread through the shed or a rapier and rapier gripper is used, the weft thread being transferred from the rapier gripper to the rapier rapier within the shed. The grippers have thread clamps, which in the first-mentioned embodiment are controlled outside the shed and in the second embodiment inside the shed positively, that is to say, forcibly. Mechanical or electromechanical means (GB 2 059 455 A; EP 0 690 160 A) are used for this purpose, the actuating element for opening or closing the thread clamp being arranged outside or below the shed. In particular with thread transfer within the shed, this essentially results in the following disadvantages.

If mechanical means are used, it must Actuator inserted between the warp threads to operate the thread clamp.

If electromagnetic means are used, the trigger magnet must be placed outside the shed. The air gap between the armature and the magnetic core thus becomes large, as a result of which a higher field strength must be generated, ie a winding with a higher ampere number of turns is required. Since this release magnet can be switched sluggishly, the speed of the weaving machine is reduced.
When the thread is transferred within the shed, the distances of the grippers overlap in the transfer area. Ie the thread transfer takes place while the grabber and the picker are still in motion. At this time, the thread clamp is actuated, during which the actuating element exerts pressure on the hook. For the elements involved in the actuation of the thread clamp, such as the looper belt or the looper webs or the shop bench and belt guide or rod guide, this results in a higher load and wear. In addition, this pressurization presses the belt gripper against the warp threads, thus causing warp thread breaks. For this reason, the gripper belt and its guides must be made stronger. It follows that the moving masses become larger, which is contrary to the demand for the smallest possible masses and thus a reduction in the speed of the weaving machine. It must also be taken into account that, due to the high cadence, the grippers in the shed vibrate in the area of the transfer and can collide with the actuating elements. As a result, special measures are required in order to reduce vibrations with such a frequency and amplitude as much as possible.

As is well known, the clamping force is due to the type of thread predetermined. With the mechanical as well as with the Electromechanical control of the thread clamp are therefore adjust the clamping force accordingly. For weaving with Different types of thread prove to be such Controls at least restrictive because on the one hand an average clamping force was determined by means of tests must be and on the other hand an adjustment of the Clamping force during the operation of the weaving machine and in particular along the path between the actuators not possible and is therefore not provided.

a) Bringergreifer: Ansteuerung in der Fachmitte,

b) Holergreifer: Ansteuerung in der Fachmitte,

c) Bringergreifer: Ansteuerung der Fadeneinlesung an der Eintragseite,

d) Holergreifer: Fadenfreigabe an der Fangseite und

e) Bringergreifer: Ansteuerung der Entlüftung an der Eintragseite.

The embodiments described above also have the disadvantage that an arrangement of actuating elements for controlling the thread clamp is assigned to each influencing point, namely:

a) Bring gripper: control in the center,

b) Holer gripper: control in the center,

c) Bring gripper: control of the thread reading on the entry side,

d) Holer gripper: thread release on the catch side and

e) Bringer gripper: control of the ventilation on the entry side.

1) Wartung von bis zu fünf Anordnungen;

2) Hohe Ausfallrate;

3) Abfall im Nutzeffekt und

4) Hoher Kostenaufwand.

Thus, up to five arrangements of actuators are required, which must be controlled individually. This has the following disadvantages:

1) maintenance of up to five assemblies;

2) high failure rate;

3) waste in efficiency and

4) High cost.

Thus, the known versions for individual control the thread clamps in particular along the path between the actuators unsuitable.

The closest prior art according to the preamble of Claim 1 results from the embodiment of the figure 17 of EP 0 690 160A. A gripper is shown and described there, one actuator designed as a piezo element contained in the housing of the gripper. The expansion of the piezoelectric Actuator when applying a voltage is used for Closing the thread clamp, that is to put on the movable one Clamping part on the fixed clamping part. The contraction the piezoelectric actuator in the de-energized state to open the thread clamp, that is, to release the movable one Clamping part from the fixed clamping part.

The object of the invention is a gripper of the type mentioned to improve to avoid the disadvantages described.

The task is characterized by the features of the claim 1 solved.

The fact that the movable clamping part with preload on immobile clamping part is pending a secure recording and a secure hold of the weft thread is guaranteed and that too when there is a power cut. By the preload on the clamping part also needs the holding force of Actuator should not be excessively large because the entire Clamping force is composed of the holding force A and the clamping force B of the actuator. This makes an actuator with less Performance can be used. Nevertheless, due to the dissolving power, which the holding force in the opposite direction exceeds a safe one Guaranteed opening of the clamp, this opening process can also be done again in two stages, initially by switching off the clamping force on the actuator so that the Weft only by the clamping force of the movable Clamping part is obtained and then further by additional Apply a release force that the movable clamping part from fixed clamp part lifts off and a gap for cleaning releases.

The thread clamp of the hook is replaced by one in the hook arranged actuator positively controlled, i.e. without from external forces, so that any load on the Rapier head, the rapier guide and the warp threads is avoided. Subsequent adjustments and Repairs to the gripper elements largely. It will Warp thread breaks avoided, reducing operating costs be significantly reduced and web performance significantly is increased. The thread clamp can during the Operation of the weaving machine and within a weaving cycle by the shot of the physical and technical web data of the weft thread to be entered is influenced accordingly become. The setpoint of the The clamping force of the thread clamp is set and regulated.

1. Der Bringergreifer übernimmt den Schussfaden vom Fadenvorleger und

2. transportiert den Schussfaden in das Webfach;

3. der Schussfaden wird etwa in der Fachmitte vom Bringergreifer an den Holergreifer übergeben;

4. am Ende des Eintragvorganges gibt die Fadenklemme des Holergreifers den Schussfaden frei;

5. die Fadenklemmen werden zur Reinigung gelüftet und

6. falls erforderlich wird die Klemmkraft der Fadenklemmen geändert.

The thread clamp performs the following functions during the weft insertion cycle:

1. The rapier gripper takes the weft thread from the thread feeder and

2. transports the weft into the shed;

3. the weft thread is passed from the rapier gripper to the holer rapier approximately in the middle of the compartment;

4. at the end of the entry process, the thread clamp of the holer gripper releases the weft thread;

5. The thread clamps are released for cleaning and

6. If necessary, the clamping force of the thread clamps is changed.

The thread clamps for the bringer and holster are formed substantially similar, which makes the Actuation of the actuators using the same Control device takes place. This will make the Manufacturing costs significantly reduced. Through the Use of transformers to actuate the Thread clamp becomes a force on the hook avoided. Because of these measures, one is possible Rapier weaving machine with up to 1000 revolutions per minute with simultaneous processing of different Yarns like zero twist or pimple yarn.

Fig. 1

Eine erste Ausführungsform eines erfindungsgemässen Greifers;

Fig. 2

eine zweite Ausführungsform eines erfindungsgemässen Greifers;

Fig. 3

eine dritte Ausführungsform eines erfindungsgemässen Greifers;

Fig. 4

ein Kraft/Zeit-Diagramm, des Zyklus der Fadenklemmwirkung innerhalb eines Schusseintrages und

Fig. 5

eine Ausführungsform einer erfindungsgemässen Schusseintragvorrichtung.

The invention is explained below with reference to the accompanying drawings.
Show it:

Fig. 1

A first embodiment of a gripper according to the invention;

Fig. 2

a second embodiment of a gripper according to the invention;

Fig. 3

a third embodiment of a gripper according to the invention;

Fig. 4

a force / time diagram, the cycle of the thread clamping effect within a weft insertion and

Fig. 5

an embodiment of a weft insertion device according to the invention.

Reference is made to FIG. 1, the one Embodiment of a gripper according to the invention shows. The gripper contains a housing 1, an electromagnet 2 and a thread clamp 3. The housing 1 consists of a Base body 4 and a cover 5, which means not represented means are interconnected. The Electromagnet 2 is arranged on the one hand on the base body. The thread clamp 3 comprises a clamping lever 6, which as Two-armed lever designed and on an axis 7 is arranged pivotably and one on the base body 4 trained clamping surface 8. A lever arm has one Clamping section 9, which is connected to the base body 4 trained clamping surface interacts and at the free End an angled section 10 together with the main body an inlet gap for a weft (not shown) forms. On the inlet side of the The end facing away from the gripper is on the base body 4 Connection section 11 for a transport unit educated. Furthermore, a spring 12 is provided around the Bias clamping section 9 against the clamping surface 8. The gripper is also with a stop member 15 for the Equipped weft. To generate the translational movement to operate the clamping lever can use a linear motor or a servo motor become. If such drive means are used, then is the clamping lever with the drive axis of the Motors coupled.

In the embodiment according to the invention according to FIG. 2 the gripper contains a housing 21, a thread clamp 22 and a piezo quartz element 23. The housing consists of a base body 24 and a cover part 25. Die Thread clamp comprises a strip-shaped clamping part 26, which consists of a resilient material and one formed on the base body 24 clamping section 17. Der Clamping part 26 is at one end on the base body 24 attached and angled at the other end Provide section 27, one with the base body Inlet gap for a weft thread, not shown forms. The clamping part 26 is with a shoulder 28 and provided a pin 29 which projects transversely to the neck. The Piezo quartz element 23 is on the one hand on the base body attached and on the other hand with a coupling part 30th provided, which is engaged with the pin 29. To the The end facing away from the inlet side of the gripper is at Base body 24 of the connection section 11 for the Transport unit trained.

The embodiment according to the invention shown in FIG. 3 differs from that of Fig. 1 by the Training and arrangement of the electromagnet. The gripper includes a housing 31, a thread clamp 32 and one Electromagnet 33. The housing consists of a Base body 34 and a cover 35. The thread clamp 32 does not include a management body 36 for one shown weft and a clamping part 37. Das Guide member 36 is strip-shaped and has an angled section 38. The clamping part 37 is also strip-shaped and has one angled section 39. The clamping part on the Guide part arranged so that the angled section 38, 39 a V-shaped Inlet gap for a weft thread, not shown form. The electromagnet 33 has a U-shaped core - 43-and a winding 40- and is below the Guide part arranged so that the guide part on rest on the end faces of the legs of the core. at In this embodiment, the guide part 36 consists of magnetically non-conductive material during the clamping part 37 forms the magnet armature and made of magnetically conductive Material exists. The base body 34 also has the Connection section 11 for the transport unit. Instead of the stop organ is with this Embodiment provided a stop bracket 41.

In the above-described embodiments the actuator is actuated by induction. This is a primary induction coil 70 which is outside the Gripper is arranged and a secondary Induction coil 71 provided in the housing 1,21,31 des Gripper is arranged. In the housing are also a Power converter and amplifier 72 arranged over Connection lines 52 are connected to the actuator. in the Cover part 5, 25, 35 is an opening 75 in each case intended.

5 is referred to. The following The embodiment according to FIG. 2 is described based. The figure shows a diagram with an abscissa for the angle of rotation of the main shaft of the weaving machine and with an ordinate for the clamping force. As the figure shows are dependent on the angle of rotation for the thread clamp three operating positions defined, namely hold A, Terminals A + B and ventilation A-C. Every operating position is assigned a force A, B, C. The holding force A is applied exclusively by the resilient element 26 and also acts when the weaving machine and the actuator are switched off first inserted into the open thread clamp and then with the clamping force B generated by the actuator applied. The weft thread is clamped with a force which is the sum of the forces A + B. The Clamping force B is continuously adjustable up to the maximum, to safely avoid weft losers. During the Transfer of the weft thread from the rapier to the According to one, the actuators become grabbers Control program reversed so that a ventilating force is generated, which is the difference of the forces A-C. After completing the registration process, the in Blown out thread clamp located in the ventilation position become. The above process applies to the Bring gripper and also for the hand gripper contrary cycle.

6 shows a weft insertion device with a Bring gripper 61, a Holger gripper 62, one Transport unit 64, which the Bringer- or the Holer rapier each over the middle 63 of the weaving width promoted and a device for operating the Actuators. The transport unit 64 is a gripper belt 66 with a guide 69 and a belt wheel 67, which with a Drive means, not shown, is drive-connected. The gripper belt is made of a flexible material, e.g. Plastic composite. The facility for Actuating the actuators is in the area of Thread transfer above the formed shed and is arranged on both sides of the center 63. The facility contains two air transformers or converters, which one a primary induction coil 70 and that on the gripper 61, 62 arranged secondary induction coil 71 includes and a control device 65, each via lines 68 connected to the primary inductor 70 to the primary induction coils depending on the Angle of rotation of the main shaft of the weaving machine and / or the to control textile or web technical data.

Claims (7)

1. Gripper for a gripper weaving machine, containing a housing (1, 21, 31) with a connecting portion (11) for a gripper band or a gripper rod (66), a thread clamp (3, 22, 32) with a fixed clamping part (8, 17, 36) and with a moveable clamping part (6, 26, 37), an electrically operable actuator (2, 23, 33) which is arranged in the housing and is drive-connected to the moveable clamping part, in order to control the clamping force and the clamping cycle of the thread clamp, characterized in that the moveable clamping part (6, 26, 37) is prestressed against the fixed clamping part (8, 17, 36) by means of a holding force, and in that the actuator (2, 23, 33) is capable of being changed over from a clamping force (B) acting in the direction of the holding force (A) into a release force (C) which counteracts the holding force (A) and which is greater than the holding force (A), whereby the clamping force (B) is continuously adjustable.
2. Gripper according to Claim 1, characterized in that the actuator is an electromagnet (2, 33).
3. Gripper according to Claim 1, characterized in that the actuator is a piezoelectric element (23).
4. Gripper according to Claim 1, characterized in that the actuator is a linear motor or a stepping motor.
5. Gripper according to one of Claims 1 to 4, characterized in that the actuator (2, 23, 33) is connected to a secondary induction coil (71) which is intended to co-operate with a primary induction coil (70), arranged outside the gripper, of a device (65) for operating the actuator (2, 23, 33).
6. Weft insertion device for a gripper weaving machine, with a transport unit (64) for a feed gripper (61) and a pick-up gripper (62), in order to move the grippers back and forth in translational motion, and with a gripper according to one of Claims 1 to 5, characterized by a device (65, 68, 70, 71) for operating the actuator (2, 23, 33) and by a control device (65) in order to control the actuator (2, 23, 33) as a function of the angle of rotation of the main shaft and/or the textile or weaving data.
7. Device according to Claim 6, characterized in that the control device (65) has a microprocessor in order to control the actuator by the open-loop or closed-loop method.

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