Yarn tensioning system and method for keeping a yarn which is taken from a yarn storage system to a yarn take-off system of a weaving machine under tension

Abstract

Disclosed is a yarn tensioning system for keeping at least one yarn, which is taken from a yarn storage system to a yarn take-off system of a weaving machine, under tension. The system includes a brake roller around which the yarn is at least partially wound, and a motor for supplying a torque to the brake roller, the motor being actuable in generator operation to keep the yarn under tension between the brake roller and the yarn take-off system. Also disclosed is a weaving machine including such a yarn tensioning system, as well as a method for keeping at least one yarn under tension, the at least one yarn being taken from a yarn storage system to a yarn take-off system.

Claims

1. A yarn tensioning system for keeping at least one yarn under tension, the system comprising: a brake roller rotatably arranged in a yarn tensioning system, at least one yarn that is at least partially wound around the brake roller, a motor supplying torque to the brake roller, wherein the motor is actuable in generator operation to keep the at least one yarn under tension, wherein the motor is actuable in motor operation to recover the at least one yarn between the brake roller and the yarn take-off system in a second direction that is opposite to the first direction, and a funnel-shaped guide for guiding the at least one yarn to the brake roller, wherein the funnel-shaped guide comprises a top open end and a bottom open end, wherein the top open end is wider than the bottom open end, wherein the at least one yarn is taken, under tension, from a yarn storage system in a first direction to a yarn take-off system of a weaving machine.

2. The yarn tensioning system of claim 1, further comprising: a tubular guide for guiding the at least one yarn to the funnel-shaped guide.

3. The yarn tensioning system of claim 1, wherein the motor is individually actuable.

4. The yarn tensioning system of claim 1, further comprising: a central control unit, and a means for providing energy generated during the generator operation of the motor to the central control unit.

5. The yarn tensioning system of claim 4, further comprising: energy storage for storing energy generated during the generator operation of the motor, wherein the motor is capable of being driven by the stored energy in the energy storage.

6. The yarn tensioning system of claim 1, further comprising: measurers for determining a length of the yarn that is taken off by the yarn take-off system.

7. The yarn tensioning system of claim 1, further comprising: time monitors for keeping track of a time during which the motor operates in motor operation to recover the at least one yarn, and for comparing the time with a pre-determined reference value.

8. The yarn tensioning system of claim 1, further comprising: signal receivers for receiving signals from the yarn take-off system, parameter measurers for measuring parameters related to operation of the yarn take-off system, and tension monitors for monitoring the measured parameters relative to the received signals.

9. The yarn tensioning system of claim 1, further comprising: a tension measuring device for measuring tension of the at least one yarn.

10. The yarn tensioning system of claim 9, further comprising: actuators for actuating the motor based on the measured tension, and communicators for communicating the measured tension from the tension measuring device to the actuators.

11. The yarn tensioning system of claim 1, further comprising: a brake roller and a motor for each yarn of the at least one yarn.

12. The yarn tensioning system of claim 1, wherein the motor is a pancake motor.

13. The yarn tensioning system of claim 1, further comprising: a tension roller that is arranged in a clamped manner against the brake roller to clamp the at least one yarn between the brake roller and the tension roller.

14. The yarn tensioning system of claim 1, wherein the brake roller winds the at least one yarn several times around the brake roller.

15. The yarn tensioning system of claim 1, further comprising: a braking device for braking the at least one yarn to prevent the at least one yarn from slipping on the brake roller.

16. The yarn tensioning system of claim 1, wherein the brake roller comprises a running surface for at least partially winding the at least one yarn around the brake roller, wherein the running surface comprises an anti-slip layer and/or a profiling.

17. The yarn tensioning system of claim 1, wherein the yarn tensioning system is part of a weaving machine that further comprises the yarn take-off system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will now be explained in more detail through the following detailed description of an embodiment of a yarn tensioning system and a method according to the present invention. The sole aim of this description is to give illustrative examples and to indicate further advantages and particulars of the present invention, and can therefore should not be interpreted as a limitation of the area of application of the invention or of the patent rights defined in the claims.

(2) In this detailed description, reference numerals are used to refer to the attached drawings, in which:

(3) FIG. 1 diagrammatically shows a first embodiment of a yarn tensioning system according to the present invention in side view with a yarn which is taken from a yarn storage system in a first direction to a yarn take-off system of a weaving machine or is recuperated in a second direction, opposite to the first direction, between the yarn tensioning system and the yarn take-off system;

(4) FIG. 2 diagrammatically shows a second embodiment of a yarn tensioning system according to the present invention in front view;

(5) FIG. 3 shows the yarn tensioning system from FIG. 2 in side view;

(6) FIG. 4 shows a third embodiment of a yarn tensioning system according to the present invention in front view, without yarn;

(7) FIG. 5 shows the yarn tensioning system from FIG. 4 partially in cutaway perspective view, without yarn;

(8) FIG. 6 shows the yarn tensioning system from FIG. 4 in perspective with yarn that is herewith tensioned.

DETAILED DESCRIPTION OF EMBODIMENTS

(9) The figures show some examples of yarn tensioning systems (1) according to embodiments of the present invention.

(10) These yarn tensioning systems (1) each comprise, for each yarn (2) to be tensioned, a brake roller (5) which is rotatably arranged and a motor (6) for supplying a torque to the brake roller (5).

(11) In the first embodiment illustrated in FIG. 1, a yarn (2) taken from a yarn storage system (3) in a first direction (A) to a yarn take-off system (4) of a weaving machine, or recuperated in a second direction (B), opposite to the first direction (A), between the brake roller (5) and the yarn take-off system (4), is wound several times around the brake roller (5) to limit slipping of the yarn (2) with respect to the brake roller (5).

(12) In order to further limit slipping of the yarn (2) with respect to the brake roller (5), this yarn tensioning system (1) furthermore comprises a braking device (7) which is arranged between the yarn storage system (3) and the brake roller (5).

(13) In order to prevent the yarn (2) from running off the brake roller (5), the brake roller (5) is provided with flanges (9) which limit the running surface (8) for the yarn (2). The running surface (8) of this brake roller (5) may be provided with an anti-slip layer by coating it, for example with rubber.

(14) In the second embodiment, which is illustrated in FIGS. 2 and 3, the yarn tensioning system (1) comprises a tension roller (10). In order to limit slipping of the yarn (2) with respect to the brake roller (5), springs (11) push the shaft (12) of this tension roller (10) towards the brake roller (5), so that the tension roller (10) is arranged in a clamped manner against the brake roller (5) to clamp the yarn (2) between the brake roller (5) and the tension roller (10).

(15) In the third embodiment, which is illustrated in FIGS. 4 to 6, the yarn tensioning system (1) is configured to keep 8 yarns (2) under tension. These yarns (2) may be, for example, warp threads (2) which are fed to a carpet weaving machine as yarn take-off system (4). To this end, the yarn tensioning system (1) comprises a brake roller (5), a motor (6) and a tension roller (10) as in the second embodiment for each yarn (2). For the sake of clarity of the figures, only one motor (6) is shown. Each yarn (2) is fed through a holder (15) via a corresponding tubular guide (14) and is passed to the corresponding brake roller (5) via a funnel-shaped guide (13), wound around this brake roller (5) and fed to the yarn take-off system in a first direction (A) through an eyelet (17). The outlet opening (16) of the tubular guide (14) is smaller than the inlet opening to the funnel-shaped guide (13). The funnel-shaped guide (13) comprises a cup-shaped cavity in which the yarn (2) is collected in the case of yarn recuperation in a second direction (B).

(16) In all illustrated embodiments, the motor (6) is a pancake motor (6) which is configured to supply a torque to the brake roller (5). On the one hand, the motor (6) is actuated in generator operation to keep the yarn (2) under tension. On the other hand, the motor (6) is actuated in motor operation to recuperate the yarn (2) between the brake roller (5) and the yarn take-off system (4) in a second direction (B), which is opposite to the first direction (A).

(17) The yarn tensioning systems (1) comprise a central control unit (not shown) and means for immediately providing the energy generated during the generator operation of the motor (6) available to this central control unit of the yarn tensioning system (1). Alternatively, the yarn tensioning systems (1) could comprise energy storage for storing energy generated during the generator operation of the motor (6), so that during the motor operation of the motor (6), the motor (6) is driven via the stored energy.

(18) Preferably, the yarn tensioning systems (1) also comprise a tension measuring device (not shown) for measuring the yarn tension. This measured yarn tension is then communicated to actuators for actuating the motor (6), preferably via communicators, so that this motor (6) can be actuated on the basis thereof. In addition, the yarn tensioning systems (1) may comprise indicators for generating a signal with regard to the measured yarn tension and communicators for communicating the measured yarn tension of the tension measuring device to these indicators.

(19) By referring to the speed of the motor (6) and the diameter of the brake roller (5), the length of the yarn (2) which is taken off by the yarn take-off system (4) can be easily determined.