WO2003038170A1

WO2003038170A1 - Method and device for supplying weft thread in a wearing machine, as well as a brake and/or damper mechanism applied thereby

Info

Publication number: WO2003038170A1
Application number: PCT/BE2002/000161
Authority: WO
Inventors: Jean-Marie Bamelis; Herman Salomez; Arnold Moerman; Chris Delanote; Jozef Peeters
Original assignee: Picanol N.V., Naamloze Vennootschap
Priority date: 2001-10-29
Filing date: 2002-10-25
Publication date: 2003-05-08
Also published as: CN1578859A; EP1442166B1; DE60235483D1; BE1014441A3; CN1578859B; ATE458843T1; EP1442166A1

Abstract

Method for supplying weft thread in a weaving machine, in particular a pneumatic loom, whereby weft thread (2) is taken from a weft accumulator (5) and this weft thread (2) is brought in the shed (7) via insertion devices (6), and whereby this weft thread (2) is carried between the above-mentioned weft accumulator (5) and above-mentioned insertion devices (6) along a brake and damper mechanism (20) with which, during the insertion cycle, it is possible to exert a brake action as well as a damping action on the weft thread (2), characterised in that the weft thread (2) is carried, in the above-mentioned brake and damper mechanism, along at least one movable thread guide (21-24) on the one hand which can bring about a damping effect whith regard to the tension in the weft thread (2), and also along at least two other thread guides (22-23-24-25-39-40) on the other hand, of which at least one can be moved and which always allow for a bending, irrespective of the position of the first-mentioned thread guide (21-24).

Description

Method and device for supplying weft thread in a weaving machine, as well as a brake and/or damper mechanism applied thereby.

The present invention concerns a method and a device for supplying weft thread in a weaving machine, as well as a brake and/or damper mechanism for weft thread applied thereby.

It is known that in weaving machines, the weft thread is taken from a weft accumulator, and this weft thread is brought in the shed via insertion devices, after which the inserted length of weft thread is beaten against the cloth line in the known manner by means of the reed.

Especially in pneumatic looms, where the weft thread is inserted by means of nozzles, in particular one or several main nozzles and relay nozzles, it is known that the weft thread is exposed to relatively large tensions, which may lead to thread breaks. These tensions occur especially at the end of the insertion cycle. As is known, the supply of weft thread is interrupted at the end of the insertion cycle by blocking the weft thread on the insertion side of the shed. Due to this sudden blocking, and also because the weft thread has a certain inertia, relatively large tensions arise.

In order to prevent the risk of thread breaks, it is known to brake the weft thread at the end of the insertion cycle, as a result of which the speed is reduced and the stress peak which is created due to the sudden blocking at the end of the cycle is minimised. In order to further level such stress peaks, it is also known to make use of damper systems, for example thread guides which bend the weft thread locally with a certain force, such that these thread guides, when a certain tension is exceeded, spring back and create a damping effect.

An example of such a method and device for inserting weft thread, whereby a brake action as well as a damping action takes place, is known from EP 0.356.380. In this known embodiment, the braking and damping always go hand in hand, as the bending of the weft thread, which is necessary for the braking action, is partly brought about by means of the element providing for the damping.

The present invention aims a method and device for supplying weft thread which are improved in relation to the known embodiments.

To this aim, the invention in the first place concerns a method for supplying weft thread in a weaving machine, in particular a pneumatic loom, whereby weft thread is taken from a weft accumulator and this weft thread is brought in the shed via insertion devices, and whereby this weft thread is carried between the above-mentioned weft accumulator and above-mentioned insertion devices along a brake and damper mechanism with which, during the insertion cycle, it is possible to exert a brake action as well as a damping action on the weft thread, characterised in that the weft thread is carried, in the above-mentioned brake and damper mechanism, along at least one movable thread guide on the one hand, which can bring about a damping effect with regard to the tension in the weft thread, and also along at least two other thread guides on the other hand, of which at least one can be moved and which always allow for a bending, irrespective of the position of the first-mentioned thread guide. This method offers the advantage that when the thread guides which have to bring about the brake effect are excited, a bending is always guaranteed, even when, due to a failure of the thread guide which has to bring about the damping effect, the latter thread guide can no longer provide for a bending as such. Hence, this also implies that the brake effect remains guaranteed, even when the damping action should fail .

Another advantage consists in that the brake effect, if required, can be disconnected from the damping effect.

Preferably, the thread guides which make sure that a bending of the weft thread is always possible, or at least the movable thread guide or thread guides that are part of them, are driven and moved by means of a position control, for example by means of a step motor. Thus can be obtained a very precise bending, outward bending respectively, of the weft thread, as well as a brake effect, whereby the position can be determined and can possibly be continuously adjusted as a function of several parameters.

Preferably, the movable thread guide which is intended to bring about a damping effect is forced with a certain force out of the path of the weft thread, at least during certain parts of the insertion cycle. In this manner, it is possible to set a specific stress level above which damping occurs .

More in particular, the movable thread guide which aims to bring about a damping effect is preferably forced into a stop position by means of said force, with such a force that this thread guide, at least while said force is being exerted, is only released from the stop position during stress peaks in the weft thread. The use of a stop position offers the advantage that the thread guide bringing about the damping effect remains in one and the same position during the normal brake action, so that the bending of the weft thread can only be controlled by means of the movement of the other thread guides, which allows for an accurate adjustment.

According to a preferred embodiment, the thread guide which aims to bring about a damping effect is excited with gas pressure, at least during the periods when a damping action is required, in particular air pressure, either overpressure or underpressure. Such a control by means of gas pressure, in particular air pressure, offers the advantage that one has a relatively large adjustment range.

In a particularly preferred embodiment, the movement of said thread guide is carried out by means of a transmission mechanism upon which can be exerted a force by means of gas pressure on one side, resulting in a lateral force on the thread guide on the other side, whereby the above-mentioned transmission has such a transmission ratio that there is a force reduction. The use of such a transmission makes it possible for the large adjustment range, which is available thanks to the use of air pressure, at least the use of overpressure, to be converted in optimal forces at the height of the thread guide. Moreover, this offers the advantage that a very precise adjustment can be obtained.

Practically, use is preferably made of a transmission mechanism with a transmission ratio, so that the force is at least reduced by half, in other words, a specific force is obtained by means of a gas pressure, resulting in a force at the thread guide which is half or less than half of the first -mentioned force. In order to make sure that the parts which have to provide for the damping take up as little space as possible, use is preferably made of a rotating lever for the above-mentioned transmission mechanism, onto which the above-mentioned thread guide is provided at one end, while the other far end works in conjunction with a little pressure cylinder.

It is clear that the invention also concerns a device for supplying weft thread in a weaving machine which makes it possible to realise the above-mentioned method. The construction of such a device will become clear from the following description.

It should be noted that the advantages obtained when a damping effect is brought about thanks to the combination of an excitation with gas pressure on the one hand, and a transmission mechanism which converts the force generated by the gas pressure into a smaller force exerted at a thread guide, can also be useful in other devices than those described above. This combination of characteristics thus forms an inventive idea which can be applied in all sorts of devices for supplying weft thread in weaving machines, irrespective of whether there is a brake effect or not, and irrespective of the manner in which such brake effect is possibly brought about.

According to a second aspect, the invention thus also concerns a device for supplying weft thread in a weaving machine, in particular in a pneumatic loom, whereby this device comprises a damper mechanism for stress peaks in the weft thread, with a thread guide which, under the influence of the thread tension, can be moved against a specific force, characterised in that this damper mechanism for exciting and moving the thread guide bringing about the damping action comprises devices, such as a little pressure cylinder or such, which can be excited by means of a gas pressure, in particular air pressure, either overpressure or underpressure, whereby these devices are connected to the above-mentioned thread guide via a transmission, whereby this transmission provides for a force reduction.

It is clear that the invention also concerns brake and/or damper mechanisms for weft thread in a weaving machine with which the above-mentioned method and devices can be realised.

In order to better explain the characteristics of the invention, the following preferred embodiments are described as an example only without being limitative in any way, with reference to the accompanying drawings, in which:

figure 1 represents a weaving machine in perspective equipped with a device according to the invention; figure 2 schematically represents a device according to the invention; figures 3 to 6 represent the part indicated by F3 in figure 2 to a larger scale, for different positions; figure 7 is a view in perspective of a practical embodiment of the above-mentioned part, placed flat; figures 8 and 9 represent a section according to line

VIII-VIII in figure 7 for two different positions; figures 10 to 12 represent the part indicated with F10 in figure 7, for different positions; figures 13 to 15 schematically represent a variant of the device according to the invention, also for different positions.

As is represented in figures 1 and 2, the invention concerns a device 1 for supplying weft thread 2 in a weaving machine 3. This device 1 comprises devices 4 for supplying weft thread 2 from a weft accumulator 5, as well as insertion devices 6 to systematically bring the supplied weft thread 2 in the shed 7.

In the given example, the weft accumulator 5 consists of one or several bobbins 8, while the devices 4 are formed of an accumulator 9 which, as is known, consists of a prewinder drum 10 upon which weft thread 2 can be wound by means of a winding arm 11, and along which is provided a pin 12 which can be activated which, by means of a control, allows weft thread 2 to be either or not taken from the prewinder drum 10.

The actual insertion devices 6 consist of_. one or several nozzles, in this case a main nozzle 13 and several relay nozzles 14 provided in the shed 7.

Further, also the reed 15 and the formed cloth line 16 are indicated in figure 2, as well as the warp threads 17, a thread collection element 18 arranged at the end of the shed 7 and a weft cutter 19 arranged at the inlet of the shed 7.

The present invention is^" special in that the device 1 comprises a brake and damper mechanism 20 for the weft thread which is provided between the above-mentioned devices 4 and the insertion devices 6, whereby this brake and damper mechanism 20 at least consists of at least one movable thread guide 21 which can bring about a damping effect with regard to the tension in the weft thread 2, as well as of at least two other, in this case even four other thread guides 22-23-24-25, at least one of which, but in this case two, namely 23 and 24, are movable, which always allow for a bending, irrespective of the position of the first-mentioned thread guide 21.

As is schematically represented in figure- 3, the thread guides 22 and 25 are preferably arranged fixed, and the thread guide 21 is situated in line with the thread guides 22 and 25 when in rest. The movable thread guides 23 and 24 are situated in such a position when in rest that they do not provoke a bending of the weft thread 2, at least when the thread guide 21 is in rest as well.

The thread guides 21, 22 and 25 preferably consist, as represented, of thread eyes, while the thread guides 23 and

24 are formed of elements which are arranged alongside the weft thread 2.

The thread guides 21, 23 and 24 are movable in directions which stand crosswise to the general feed-through direction of the weft thread 2. The thread guides 23 and 24 are fixed to one another and can be moved together by means of drive devices 26 which preferably allow for a position control, in other words which make it possible to bring the thread guides 23 and 24 in one or several specific positions, possibly as a function of different parameters and either or not as a function of the course of the insertion cycle. In a practical embodiment, these drive devices 26 consist of a controllable step motor.

In order to excite the thread guide 21, such that a damping effect can be obtained, the yarn break mechanism 20 is provided with devices 27 with which a certain force F can be exerted on the thread guide 21, according to the direction of movement in which the thread guide 21 can be moved. These devices 27 preferably consist of a drive element which can be switched on and off which, when switched on, forces the thread guide 21 into a stop position with said force F, determined by a stop 28, such that, in this stop position, the thread guide 21 is situated in the prolongation or almost the prolongation of the path which is normally followed by the weft thread 2, in other words in the position as represented in figure 3.

The devices 27 make it possible to set the value of the force F such that the thread guide 21 can only be released from the stop position during stress peaks in the weft thread 2.

Further, the devices 27 are preferably made such that, when these devices 27 are not excited, the thread guide 21 concerned freely follows the position of the weft thread 2.

The working and the method related to it are described hereafter with reference to the different positions in figures 3 to 6.

When a length of weft thread 2 must be inserted in the shed 7, the weft thread 2, as is generally known, is released at the accumulator 9 by withdrawing the pin 12, and the weft thread 2 is blown in the shed 7 by activating the nozzles concerned, in particular the main nozzle 13 and the relay nozzles 14. As a result, the weft thread 2 will move through the shed 7, until its front end has reached the far end of the shed 7. At that moment, the yarn supply as of the accumulator 9 is interrupted by exciting the pin 12.

In order to exclude excessive tensions in the weft thread 2, as explained in the introduction, a yarn brake as well as a tension damping are provided during the weft cycle by means of the yarn brake mechanism 20. At the start of the insertion cycle, the thread guides 21 and 23-24 are in the position as represented in figure 3, whereby it is clear that there is no braking or damping whatsoever, as all these guides are in line with the fixed guides 22 and 25.

It should be noted that the devices 27 are preferably permanently excited, and the guide 21 is thus permanently pushed into the stop position.

Towards the end of the insertion cycle, the thread guides 23 and 24 are moved by means of the drive devices 26, as a result of which, as represented in figure 4, several bendings are realised, so that a brake effect is created due to the ensuing friction between the weft thread 2 and the respective thread guides. As the drive devices 26 allow for a position control, the position of the thread guides 23-24 can be set as a function of different parameters, such as the required brake effect, the nature of the weft thread and the like. Also a control as a function of the course of the insertion cycle is possible, either or not on the basis of feedback values.

The brake effect reduces the speed of the weft thread 2 and thus also its remaining inertia, so that when the weft thread 2 is stopped, the yarn tension therein is lower than in the case when no braking action would have preceded.

Since the weft thread 2 is yet stopped all of a sudden, there is still a considerable increase of tension in the weft thread 2 at such time. When a certain value is exceeded, the thread guide 21 is detached from the stop 28, against the force F, as represented in figure 5, so that a damping takes place and stress peaks are attenuated. The invention is special in that, by doing as described above, it is always possible to obtain a brake effect by means of a bending, even when, due to failures, the damping effect provided by the thread guide 21, would get lost. This is schematically illustrated in figure 6. This figure shows that when a force F is no longer exerted on the thread guide 21, and the latter thus ends up in line with the thread guides 23 and 24, it is still possible to bring about a good bending and brake effect .

The invention also offers the advantage that the damping effect can be switched off, while at the same time a brake effect can still be realised.

Figures 7 to 9 represent a practical embodiment of the brake and damper mechanism 20. The thread guides 22 and 25 hereby consist of thread eyes provided in supports 29 and 30. The thread guides 23 and 24 are formed of a brace 31 mounted on a shaft 32 which can be revolved by means of a ^' step motor 33. The thread guide 21 consists of a thread eye which is provided at the end of an element which can rotate around a shaft 34, in particular a lever 35, which can work in conjunction with the stop 28.

According to a special aspect of the present invention, the mechanism 20 is provided with devices 27 which make it possible to excite the thread guide 21 by means of gas pressure, in particular air pressure, in order to obtain the above-mentioned damping effect.

To this end, the devices 27 comprise a little pressure cylinder 36 to which compressed air can be supplied via a controlled valve 37. The pressure cylinder 36 has a piston 38 which is coupled to the lever 35 so that, by supplying compressed air, the lever 35 is moved and forced against the stop 28.

The lever 35 forms a transmission mechanism which preferably provides for a force reduction, since, as indicated in figure 9, the lever arm A is shorter than the lever arm B. A is preferably smaller than or equal to the half of B, so that the force is at least reduced by half.

The working of the brake and damper mechanism as represented in figures 7 to 9 is analogous to what has been described above by means of the schematic figures 3 to 6.

When in rest, the brace 31 is in a position as represented in figures 8 and 10.

When compressed air is hereby supplied to the pressure cylinder 36, the lever 35 is pressed against the stop 28 with a certain force.

When a brake action is required, the brace 31 is rotated, which leads to a situation as represented in figure 11.

When a stress peak occurs, it will be attenuated, as the thread guide 21 and the lever 35 are then detached from the stop 28 against the force F, as represented in figure 9.

When the damper mechanism fails or no damping is required, a sound bending and brake action are still required, which is illustrated by means of figure 12.

It should be noted that the use of compressed air to activate the thread guide 21 which provides for the damping, in combination with a transmission mechanism, in particular a transmission mechanism causing a force reduction, provides major advantages as far as the possibilities to control the damping effect are concerned.

For, in this manner, it is possible to have a relatively large regulating range at the height of the pressure cylinder 36, as a pressure regulation with overpressures can for example be realised in practice, for example from 0.1 to 7 bar, which results in a factor 70. Another advantage consists in that certain deviations in the control on the input side of the transmission mechanism, by which is meant the set air pressure at the pressure cylinder 36, are hardly felt as deviations on the output side, in other words in the force F supplied to the thread guide 21. A further advantage consists in that the whole, thanks to the combination of a compressed air excitation and a transmission mechanism, can be realised in a simple and compact manner. Finally, such a system also offers the advantage that it is little sensitive to failures due to friction and such, as frictional forces are negligible compared to the forces which can be generated by means of compressed air or such.

Another advantage is the very low inertia of the transmission and its drive, since no mechanical springs or electromagnetic elements need to be used. As a result, the system concerned can easily react with a high frequency on a stepwise thread tension increase, it will have a low time constant and can easily make deflections when necessary.

It is clear that the above-mentioned combination of a compressed air excitation and a transmission mechanism can also be realised in other manners while still remaining within the scope of the invention. According to a variant which is not represented, the lever 35 can be made in a simple manner as a movable finger which can push laterally against the weft thread 2, whereby this finger is situated outside the path of the weft thread 2 when in rest, whereas it swings while being excited and is pushed with a certain force against the weft thread 2. In such an embodiment, use can be made of devices to push the above-mentioned finger with a certain force against the weft thread 2 on the one hand, and of recall devices to bring the finger in a position of rest when it is not activated on the other hand. To this end, use can be made for example of a double-acting cylinder to move the finger, whereby the excitation in one direction of movement provides for a damping and the excitation in the other direction of movement makes sure that the finger is put back in a position of rest and is held tight.

Of course, the magnitude of the force F can possibly be adjusted, for example as a function of different parameters. Such an adjustment may take place on the basis of parameters that are known beforehand, for example the type of weft thread 2, or on the basis of parameters which vary during the weaving, either or not as a function of measurement data.

It is clear that the use of a lever 35, a finger or such, also offers the advantage that relatively large deviations are possible, so that variations in the thread tension, not only as a result of the stop of the weft thread 2, but also of other nature, can be easily absorbed, such as for example an increase in tension resulting from tensile forces exerted on the weft thread 2 due to the movement of the sley or resulting from what is called residual stress. Although, in the examples from figures 2 to 11, use is always made of five thread guides 21 to 25, it is clear that the invention can also be realised with more or less of such thread guides. For clarity's sake, an embodiment is represented in figures 13 to 15 with only two thread guides 39 and 40 guaranteeing that it is always possible to realise a bending of the weft thread 2 and with a single thread guide 41 which provides for the damping. The whole of thread guides can be rotated, so that, as represented in figure 14, a bending and brake action can be realised thanks to the rotation. By moreover pushing the thread guide 41 with a certain force against the weft thread 2, as represented in figure 15, it is possible to obtain a damping effect .

It should be noted that, according to a simple embodiment, use can also be made of a spring excitation for the devices 27 which, for example in the embodiment of figures 7 to 9, permanently pushes the lever 35 towards the stop 28.

The bending of the weft thread 2 , provided for by the thread guides 22-23 and 24-25, as well as 39-40, preferably is always sufficiently large to provide for a sound brake effect in any case, irrespective of the position of the thread guides 21 and 41. Practically, this implies that, preferably in case of a brake action, irrespective of whether a damping is either or not provided for, a total bending over at least 90° is always possible, whereby the total bending is understood to mean the sum of all angles over which the weft thread 2 is bent.

The invention is by no means limited to the above-described embodiments represented in the accompanying drawings; on the contrary, such a method and device for supplying weft thread in a weaving machine, as well as the brake and/or damping mechanism used thereby, can be made in all sorts of variants while still remaining within the scope of the invention .

Claims

Claims .

1. Method for supplying weft thread in a weaving machine, in particular a pneumatic loom, whereby weft thread (2) is taken from a weft accumulator (5) and this weft thread (2) is brought in the shed (7) via insertion devices (6), and whereby this weft thread (2) is carried between the above-mentioned weft accumulator (5) and above-mentioned insertion devices (6) along a brake and damper mechanism (20) with which, during the insertion cycle, it is possible to exert a brake action as well as a damping action on the weft thread (2) , characterised in that the weft thread (2) is carried, in the above- mentioned brake and damper mechanism, along at least one movable thread guide (21-24) on the one hand, which can bring about a damping effect with regard to the tension in the weft thread (2), and also along at least two other thread guides (22-23-24-25-39-40) on the other hand, of which at least one can be moved and which always allow for a bending, irrespective of the position of the first-mentioned thread guide (21-24) .

2. Method according to claim 1, characterised in that the above-mentioned thread guides (22-23-24-25-39-40) which make sure that a bending of the weft thread (2) is always possible, or at least the movable thread guide or thread guides thereof, are controlled and moved by means of a position control.

3. Method according to any of the preceding claims, characterised in that the movable thread guide (21-41) which aims to provide for a damping effect is activated with a specific force (F) at least during certain parts of the insertion cycle.

4. Method according to claim 3, characterised in that the movable thread guide (21-41) which aims to provide for a damping effect is forced into a stop position with such a great force (F) that this thread guide (21) , at least while said force (F) is being exerted, is only released from the stop position during stress peaks in the weft thread (2) .

5. Method according to claim 4, characterised in that the stop position is selected such that the weft thread can pass freely along the thread guide (21-41) concerned when there is no brake action by means of the other thread guides (23-24) .

6. Method according to any of the preceding claims, characterised in that, for the movable thread guide (21- 41) which aims to bring about a damping effect, use is made of a thread guide (21-41) which can be laterally moved in relation to the weft thread (2) on the one hand, and which, when it is not excited, freely follows the lateral movement of the weft thread (2) resulting from the possible movement of the above-mentioned two thread guides (22-23-24-25-39-40) on the other hand.

7. Method according to any of the preceding claims, characterised in that the thread guide (21-41) which aims to provide for a damping effect, at least during the periods when a damping is required, is excited by means of a gas pressure, in particular air pressure, either overpressure or underpressure.

8. Method according to claim 7, characterised in that the movement of the above-mentioned thread guide (21-41) takes place via a transmission mechanism, onto which a force can be exerted on one side by means of gas pressure, which results in a force (F) at the thread guide (21) on the other side, whereby the above- mentioned transmission has such a transmission ratio that this results in a force reduction.

9. Method according to claim 8, characterised in that a transmission mechanism with a transmission ratio is used, such that the force is at least reduced by half.

10. Method according to any of claims 8 or 9, characterised in that, for the transmission mechanism, use is made of a rotating lever (35) onto which the above-mentioned thread guide (21) is provided at one end, whereas the other far end works in conjunction with a little pressure cylinder (36) .

11. Method according to any of the preceding claims, characterised in that the weft thread (2) is guided along at least two movable thread guides (23-24) in order to bend it, situated between two fixed thread guides (22-25) , whereas this weft thread (2) , in order to bring about the above-mentioned damping effect, is also guided through a third movable thread guide (21) , which is arranged between the above-mentioned two thread guides (23-24) .

12. Device for supplying weft thread in a weaving machine, in particular in a pneumatic loom, in particular according to the method of any of the preceding claims, whereby this device (1) at least comprises devices (4) for supplying weft thread (2) from a weft accumulator (5) , as well as insertion devices (6) to systematically bring the supplied weft thread (2) in the shed (7) of the weaving machine (3) , whereby the device (1) comprises a brake and damper mechanism (20) for the weft thread (2) provided between the above-mentioned devices (4) for supplying weft thread (2) from a weft accumulator (5) and the above-mentioned insertion devices (6) , characterised in that the brake and damper mechanism (20) comprises at least one movable thread guide (21-41) which can bring about a damping effect with respect to the tension in the weft thread (2), as well as of at least two other thread guides (22-23-24- 25-39-40) of which at least one can be moved and which always allow for a bending, irrespective of the position of the first-mentioned thread guide (21-41) .

13. Device according to claim 12, characterised in that the thread guides (22-23-24-25-39-40) which make sure that the weft thread (2) can always be bent, or at least the movable thread guide or thread guides thereof, are provided with drive devices (26) which allow for a position control .

14. Device according to claim 13, characterised in that the drive devices (26) are formed of a stepping motor.

15. Device according to any of claims 12 to 14, characterised in that the brake and damper mechanism (20) is provided with devices (27) with which a certain force (F) can be exerted on the movable thread guide (21-41) bringing about the damping effect.

16. Device according to claim 15, characterised in that the brake and damper mechanism (20) has stop-forming devices which determine a stop position for the above-mentioned movable thread guide (21-41) .

17. Device according to claim 15 or 16, characterised in that the above-mentioned devices (27) with which a certain force (F) can be exerted on the movable thread guide (21-41) bringing about the damping effect are made such that, when these devices (27) are not excited, the thread guide (21-41) concerned freely follows the possible lateral movement of the weft thread (2) .

18. Device according to any of claims 12 to 17, characterised in that, for the excitation and movement of the thread guide (21-41) bringing about the damping effect, it comprises devices, such as a little pressure cylinder (36) or such, which can be excited by means of a gas pressure, in particular air pressure, either overpressure or underpressure.

19. Device according to any of claims 12 to 18, characterised in that, for the movement of the thread guide (21-41) bringing about the damping, it comprises a transmission mechanism, onto which a force (F) can be exerted on one side by means of gas pressure, which results in a force (F) at the thread guide (21-41) on the other side, whereby this transmission mechanism has such a transmission ratio that this results in a force reduction.

20. Device according to claim 19, characterised in that the transmission mechanism consists of a rotating lever (35) onto which the above-mentioned thread guide (21-41) is provided at one end, while the other far end works in conjunction with a little pressure cylinder (36) .

21. Device according to any of claims 12 to 20, characterised in that the above-mentioned brake and damper mechanism (20) comprises at least two fixed thread guides (22-25) ; that, for the thread guides designed to provide for a bending of the weft thread (2), two movable thread guides (23-24) are provided, situated between the two fixed thread guides (22-25); and that the thread guide (21) which is meant to provide for a damping effect is situated between the above- mentioned two movable thread guides (23-24) .

22. Device for supplying weft thread in a weaving machine, in particular in a pneumatic loom, whereby this device comprises a damper mechanism for tension peaks in the weft thread (2), with a thread guide (21-41) which, under the influence of the thread tension, can be moved against a specific force (F) , characterised in that this damper mechanism, in order to excite and move the thread guide (21-41) providing for the damping, comprises devices, such as a little pressure cylinder (36) or such, which can be excited by means of a gas pressure, in particular air pressure, either overpressure or underpressure, whereby these devices are connected to the above-mentioned thread guide (21-41) via a transmission, whereby this transmission provides for a force reduction.

23. Device according to claim 22, characterised in that the transmission at least provides for a transmission ratio of 2 on 1.

24. Brake and/or damper mechanism for weft thread in a weaving machine, characterised in that it has the characteristics as described in any of claims 12 to 23.