SPINNING UNIT AND AIR JET SPINNING MACHINE HAVING SUCH A SPINNING UNIT

Abstract

An air jet spinning machine, air jet spinning machine for producing a thread from a fed sliver, and method for detecting a thread strength, which falls below a target value, of a thread produced at a spinning unit of an airjet spinning machine are provided. A thread manipulation unit is arranged in the region between the airjet spinning machine and the spooling device, which thread manipulation unit acts mechanically on the thread and exerts an adjustable thread tension influencing force, in particular an adjustable braking force, compression force and/or clamping force, onto the thread in order to variably increase thread tension. In the method, an adjustable thread tension influencing force is exerted onto the thread, and a thread breakage and/or thread breakage rate are/is detected and compared with a specified target rate, and thread breakage and/or deviations of thread breakage rate beyond a predetermined limit value are displayed and/or evaluated.

Claims

1. A spinning unit for an air jet spinning machine for manufacturing a thread from a supplied fibre band, comprising an air-jet spinning device for forming a thread from at least one fibre band fed via a drafting system, and a winding device for taking up the thread on a take-up package, characterised in that, in the area between the air-jet spinning device and the winding device, a thread manipulation unit is arranged, which acts mechanically on the thread and exerts an adjustable thread-tension-influencing force on the thread to variably increase the thread tension.

2. The spinning unit according to claim 1, characterised in that the thread manipulation unit has an adjustable clamp toward the thread.

3. The spinning unit according to claim 2, characterised in that the clamp is formed by a disc tensioner and/or gate tensioner for adjustable drawing of the thread.

4. The spinning unit according to claim 1, characterised in that the thread manipulation unit has an adjustable deflector.

5. The spinning unit according to claim 1, characterised in that the adjustable thread-tension-influencing force is electrically adjustable.

6. The spinning unit according to claim 1, characterised by a sensor for measuring the thread tension of the thread section that can be or is influenced by the thread manipulation unit.

7. The spinning unit according to claim 1, characterised in that the thread manipulation unit is arranged in the area between the air-jet spinning device and a thread take-up unit.

8. Air jet spinning machine for manufacturing a thread from a supplied fibre band, characterised by at least one spinning unit according to claim 1.

9. Air jet spinning machine according to claim 8, characterised by an associated evaluating unit for detecting a thread break and/or thread break rate at the spinning units and comparing the thread break rate with target rates that can be specified.

10. Air jet spinning machine according to claim 8, characterised by an associated controlling unit for detecting the thread tensile force by thread tensile-force sensors arranged at the spinning units and for adjusting the thread-tension-influencing force of the thread manipulation unit.

11. A method for detecting a thread strength of a thread manufactured at a spinning unit of an air jet spinning machine which falls below a target value, wherein an adjustable thread-tension-influencing force is applied to the thread by a thread manipulation unit, which is arranged in the area between an air-jet spinning device and a winding device and acts mechanically on the thread, and a thread break and/or thread break rate is detected and compared with a specified target rate, and the thread break and/or deviations of the thread break rate beyond a predefined limit value are indicated and/or evaluated.

12. The spinning unit according to claim 1, characterized in that the adjustable thread-tension-influencing force is an adjustable braking, compressive and/or clamping force.

13. The spinning unit according to claim 4, characterized in that the adjustable deflector is an adjustable eyelet for variably altering the thread path.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] An embodiment example of the present invention is explained below with reference to the drawings. In the drawings:

[0032] FIG. 1 shows a simplified view of an air jet spinning machine having several spinning units, according to a preferred embodiment example;

[0033] FIG. 2 shows a spinning unit of the air jet spinning machine from FIG. 1 in regular spinning operation and

[0034] FIG. 3 shows a thread manipulation unit of the spinning unit from FIG. 2, which thread manipulation unit has clamping means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] FIG. 1 shows a simplified representation of an air jet spinning machine 1 having a plurality of spinning units 2 arranged side by side, according to a preferred embodiment example. Each spinning unit 2 comprises a fibre band source 3, which can be designed, for example, as a spinning can, a drafting system 4, an air-jet spinning device 5, a take-up roller pair 6a, 6b, a thread clearer 7, a thread repositioning apparatus 8, a thread manipulation unit 17 as well as a cross-wound package 9 of a winding device. A service trolley 10 is movably mounted on rails 11, 12 extending along the air jet spinning machine 1. A machine end housing 13 is provided at one longitudinal end of the air jet spinning machine 1 for the arrangement of central devices required for the operation of air jet spinning machine 1.

[0036] FIG. 2 shows a spinning unit 2 according to a preferred embodiment example in regular spinning operation. A fibre band 14 supplied by a fibre band source 3 passes through a drafting system 4, in which the fibre band 14 is drafted. The drafted fibre band 14 is then fed to the air-jet spinning device 5 via a pair of output rollers 16a, 16b of the drafting system 4. In the air-jet spinning device 5, the outer fibres of the fibre band 14 are wound around the inner core fibres of the fibre band 14 due to the air flow generated within the air-jet spinning device 5 and thus form the wrap fibres, which are decisive for the desired strength of the thread 15. The spun thread 15 is taken up from the air-jet spinning device 5 by means of a take-up roller pair 6a, 6b and, after passing through the thread clearer 7 and the thread repositioning apparatus 8, is wound onto the cross-wound package 9 of the winding apparatus.

[0037] In the area between the air-jet spinning device 5 and the take-up roller pair 6a, 6b, the thread 15 passes through the thread manipulation unit 17, by means of which a thread-tension-influencing force is mechanically exerted on the thread 15, which thread-tension-influencing force results in an increase in the thread tension. The thread tension, which can be adjusted by means of the thread-tension-influencing force, depends on the expected thread strength, and the magnitude of the thread tension is set in such a way that, if the thread strength falls below an expected value, a thread break occurs due to the increased thread tension.

[0038] An embodiment example of a thread manipulation unit 17 for applying a thread-tension-influencing force to the thread 15 is shown in FIG. 3. The thread manipulation unit 17 has two clamping discs 23a, 23b, which can set to different distances apart from one another and between which the thread 15 is passed. The clamping force acting on the thread 15 is determined by the spring stress applied by a coil compression spring 21, which spring stress in turn results from the distance between the clamping disc 23a and a stop 22 adjustable along a shaft 20, against which clamping disc 23a and stop 22 the opposite ends of the coil compression spring 21 rest. An adjustment of the stop 22, and thus the setting of the distance between the clamping disc 23a and the stop 22, is carried out by means of an actuating motor 18, which is arranged on a carrier 19 and rotates the shaft 20 and is connected to an open-loop and closed-loop control unit (not shown here) of the air jet spinning machine.

[0039] According to an embodiment example not shown here, the thread manipulation unit 17 has an eyelet through which the thread 15 passes, which eyelet can be adjusted transversely to the thread running direction. The thread path is deflected by means of a displacement of the eyelet; the thread-tension-influencing force acting on the thread, in the form of a compressive force and in particular additionally in the form of a braking force, and thus the thread tension can be adjusted according to the position of the eyelet. According to a preferred embodiment example, the preferably provided additional braking force can be achieved by means of an appropriate surface coating on the surface section of the eyelet which touches or deflects the thread.

[0040] According to an embodiment example which is also not shown, a thread braking means is provided for generating such a braking force, which thread braking means comprises a thread contact section for contacting the running thread, the thread braking means being designed to brake the running thread in a defined manner by means of a braking force acting on the thread.

LIST OF REFERENCE SIGNS

[0041] 1 Air jet spinning machine [0042] 2 Spinning unit [0043] 3 Fibre band source [0044] 4 Drafting system [0045] 5 Air-jet spinning device [0046] 6a, 6b Take-up roller pair [0047] 7 Thread clearer [0048] 8 Thread repositioning apparatus [0049] 9 Cross-wound package [0050] 10 Service trolley [0051] 11 Rail [0052] 12 Rail [0053] 13 Machine end housing [0054] 14 Fibre band [0055] 15 Thread [0056] 16a, 16b Pair of output rollers [0057] 17 Thread manipulation unit [0058] 18 Actuating motor [0059] 19 Carrier [0060] 20 Shaft [0061] 21 Coil compression spring [0062] 22 Stop [0063] 23a, 23b Clamping disc