EP0518809B1 - Device to change the loop pile length of terry fabrics and loom with such device - Google Patents

Description

The invention relates to a device for changing the loop length, or loop height, when weaving terry fabrics with weaving machines, in which the loop formation takes place via the fabric table movement.

In terry weaving machines, the loops are created by weaving a so-called pile chain into the basic chain. The pile chain is woven in with the weft insertion through the compartment formed by the pile and base chain.

Terrycloth looms have the peculiarity that with a certain successive number of weft entries, the weft thread is only partially cast, ie the weft thread is integrated into the compartment, but not fully cast from the reed or reed to the fabric edge. In these shots with a partial stop, the fabric table moves from a basic position to a partial stop position that is further away from the Riet reversal point.

After the specified number of partial stops, there is a so-called full stop, in which the fabric table is usually in the basic position, i.e. is brought into the position closer to the Riet reversal point, the full stop position. In the course of this, all of the partially weft threads are attached to the fabric edge and, on the other hand, the pile warp threads are pushed open up and down, thereby forming the actual loops of the terry fabric. It is understood that in order to define the full or partial stop position, the position of the fabric edge in relation to the reversion point is decisive. The position of the fabric edge to the reed turning point is thus adjusted with the position of the fabric table.

The back and forth movement of the fabric table is usually done with a cam-controlled lever mechanism.

From EP-A-0.257.857 a device for the drive, i.e. the back and forth movement of the fabric table is known, in which the point of engagement of a drive rod on the lever arm can be changed such that the drive rod becomes shorter or longer. The size of the stroke of the lever arm is not changed, only the position of the reversal points.

This device has the disadvantage that a basic stroke predetermined by the terry cam has to be superimposed to change the loop height. This means that in the event of a deviation from a desired loop height, an adjusting device must be made for each terry weaving cycle to make a stroke correction that changes the partial stop position compared to the full stop position, i.e. the point of application of the drive rod must be changed.

The device therefore has the disadvantage that the point of attack of the Drive rod moved from the basic position to a stop position and from there must be brought back to the basic position.

This leads to high wear of parts of the actuator that are subjected to high loads. Above all, however, the requirements for the precision of the device are even higher if the position of the full and / or partial stop position of the fabric table has to be changed frequently.

The present invention is to provide a device for changing the loop height, in which the full stop or basic position remains unchanged for a change in the loop height and the partial stop position is permanently changed over several terry weaving cycles compared to the full stop position.

The present invention is also intended to provide a device for moving the fabric table, in which the drive of the lever is only to be changed in the rhythm of the change from full stop to partial stop and back to full stop, that is to say not with every terry weaving cycle. In addition, the distance of the shift between the position of the fabric table at full stop and partial stop should be able to be changed in a simple manner.

According to the invention, this is achieved with a device which has the features of independent claim 1. A weaving machine according to the invention has such a device. The dependent claims relate to advantageous developments of such devices.

The pivoting movements of the lever arm, ie the so-called pivoting stroke, are translated into the forward and backward movements of the Fabric tables of the terry weaving machine implemented. If the point of application of the drive on the lever is changed, the fabric table stroke changes even if the amplitude of the drive does not change. By changing the length of the lever arm, ie shifting the point of application of the lever drive and thus the effective length of the lever arm, the function of changing the distance between the full and the partial stop position becomes dependent on the function of the actual tissue table back and forth - Movement separated in terry weaving. The distance between the point of engagement of the drive on the lever and its pivot point is called the effective lever length. The point of application of the lever drive on the lever in terry weaving operation is not changed as long as the loop length is correct. In the solution according to the invention, the full stop, ie the basic position or basic setting of the fabric table remains unchanged even when the effective lever length is changed. This separation of the two functions leads to an increased precision of the terry apparatus, ie the terry device, without the need for additional, complex design measures.

With a weaving machine which has a device for loop formation according to the invention, it is of course also possible to use a specific pattern of terry cloth with loops of different lengths, i.e. to produce varying loop heights. For this purpose, the partial stop position is changed according to a predefined program.

Precise setting and simple changing of the swivel stroke of the fabric table is the prerequisite for the precise regulation of the loop length in the case of fabric-controlled terry towers. The exact adjustment of the loop length is of great importance for the weaver, especially for the appearance of the fabric. This is also important because in the trade of terry fabrics, which are expensive to use, the unit weight is an important price factor. Weight deviations from the target weight of ± 2% are generally tolerated. Larger downward deviations usually result in price reductions at the weaver's expense. Weight deviations upwards, i.e. terry fabrics that are too heavy with the correspondingly higher cost of materials, are also borne by the weaver without additional proceeds. So it is understandable that the weaver has an interest in making terry toweling within the tolerated weight limit of ± 2% and within this tolerance range as close as possible to the target value or even at the lower weight limit.

In this regard, a terry device with a device according to the invention has advantages in that the adjustment of the loop length can be adjusted and regulated more precisely.

The invention is explained in more detail below with reference to the examples and details shown in the figures.

Fig. 1

eine Seitenansichten einer schematisch dargestellten Frottiereinrichtung, bei welcher die Lage des Gewebetischs, mit einer Vorrichtung gemäss der Erfindung verändert werden kann;

Fig. 2

in einer Seitenansicht Einzelheiten eines anderen Hebels mit Antrieb gemäss der Erfindung.

Show it:

Fig. 1

a side views of a schematically represented terry toweling, in which the position of the fabric table can be changed with a device according to the invention;

Fig. 2

in a side view details of another lever with drive according to the invention.

In the toweling device 1, the fabric table 11 is moved by a system of levers from the basic position, the so-called full stop position V, by the distance X to the partial stop position T and back again. The fabric table 11 is shown in the basic position V in the figure. In this position, the reed or reed W, shown in its reverse and stop position, makes a full stop. The weft threads are attached to the fabric edge R. The loops of the terry fabric are formed by pushing open the pile warp threads. The arrows indicate the direction in which the various components of the lever system are moved by the distance X to the partial stop position T when they are moved. When returning to the starting or full stop position V, the movement takes place in the opposite direction of the arrow. The retraction is supported by the forces which the terry fabric F exerts on the terry device, in particular on the breast tree 19 and the drive lever 18.

The lever system is driven by the terry cam disk 12. The terry cam disc drives the roller lever 13, which in turn moves the pull hook 14. The pulling movement of the pull hook 14 is transmitted to the rocker arm 17 via the intermediate plate 15 and the pull tab 16. The sliding block 171 is at least approximately displaceable and adjustable transversely to the direction of pull of the rocker arm 17 and transmits the movement of the rocker arm 17 to the drive lever 18 and via the movable breast boom 19 to the tissue table 11.

The amplitude of the back and forth movements of the roller lever 13, the pull hook 14, the intermediate plate 15 and the pull tab 16 with the rocker arm 17 remains unchanged. In contrast, when moving the point of attack P in Area G of the sliding block 171 of the breast tree 19 with the tissue table 11 withdrawn to different degrees. The distance X between the full stop position V and the partial stop position T is thus very fine and precisely adjustable and changeable. With a change and adjustment of the distance X, the loop length of the terry fabric is also changed and adjusted.

The fabric table 11 of the device 1 is brought with a lever system from the basic position V to the partial stop position T and back to the basic position V. The lever system has a lever 18 and a drive 17, 171 acting at least approximately at right angles to this lever (18). The change in the distance X between the basic or full stop position V and the partial stop position T of the fabric table 11 is carried out by moving the drive point P of the drive 17, 171 on the lever 18 and thus the length of the effective lever arm of the lever 18. The separation of the function thus achieved of changing the position of the fabric table 11 between the full V and the partial stop position T, from the function of the actual back and forth movement of the fabric table 11 enables an improved and simplified change and adjustment of the fabric table stroke (distance X) and hence the loop length.

In the example shown in FIG. 1, the sliding block 171 is disc-driven with a spindle 172 which is driven by the stepper motor 173 via the flexible shaft 174. The sliding block 171 could of course also be moved in other ways, e.g. pneumatically, hydraulically or via a push-pull cable.

In the example shown in FIG. 1, the position of the sliding block 171 is determined by the control and regulating electronics 10 certainly. The control electronics calculate the desired position of the sliding block 171, and thus the distance X from the basic position V to the partial stop position T, for example on the basis of variables such as the pile warp speed, the pile warp tension, the number of turns of the weaving machine, the loop thread length per cm of terry cloth. The calculation is usually carried out by comparing actual values and setpoints of the quantities or of products from these quantities. If the actual sizes are measured with sufficient accuracy, the loop thread length woven in can be regulated and recorded in the range of ± 2% of the nominal value.

The pile warp or pile thread speed can be in the range from less than one meter to several meters per minute, for example 0.2 to 5 m / min. The speeds of modern terry weaving machines range from 150 to over 500 rpm.

2 shows part of a device 2 according to the invention, in which the intermediate disk 25, which is rotatable about the Z axis, drives the lever 27 via the joint 271. The effective lever arm of the intermediate disk 25 can be driven with the aid of the spindle 272, which is driven by a stepper motor 273 via an angular gear. In this example, too, the intermediate disk 25 is driven with a pull hook 24.

A construction would of course also be conceivable in which a spindle for changing the effective lever length is provided at each end of the lever 27.

Claims (10)

1. A device (1) for altering the loop length when weaving terry cloths (F), which for desplacing (X) the fabric table (11) between the full (V) and the partial beat-up position (T) comprises at least one lever (18) and a driving lever (17, 171), that acts at a working point (P; 271) and at least roughly at a right angle onto the lever (18), characterized by means (P, 171, 172, 173, 174, 10) for moving the working point (P; 171) of the driving lever (17; 27) sideward along the lever (18).
2. A device (1) according to claim 1, in which the alteration in the effective length of the lever arm (18) for the driving lever (17; 27) is performed with a spindle drive (G, 171, 172).
3. A device (1) according to claim 2, with a stepping motor (173) to drive the spindle drive (G, 171, 172).
4. A device (1) according to claim 1, in which the alteration (G) in the effective length of the lever arm (18) is performed with hydraulic and/or pneumatic means.
5. A device according to one of claims 1 to 4, having a measuring appliance to determine the pile thread velocity (actual value) and having a control and adjustment appliance (2) to alter the pile thread velocity, which contains storage means for set values of the pile thread velocity, and the adjustment and control of the pile thread velocity on the basis of the deviation of the measured actual values from the set value.
6. A device (1) according to claim 5, having means to transmit the weaving machine velocity to the control and adjustment appliance (2), and having means to determine the set values of the pile thread velocity from the R.P.M.. of the weaving machine and the specified pile length of the terry cloth (F).
7. A device (1) according to one of claims 1 to 6, having means to measure and to regulate the tension of the pile threads.
8. A device according to claim 7, having means to keep the tension of the pile warp threads constant.
9. A device (1) according to one of claims 5 to 8, having an adjusting and control appliance (2) which influences the alteration (G) in the length of the lever arm (18) for the driving lever (17), and thus the partial beat-up position (T) of the fabric table (11).
10. A loom having a device (1) for altering the loop length according to one of claims 1 to 9.

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