Device and method to protect seams on textile machines

Description

FIELD OF THE INVENTION

[0001] The invention concerns a device and a method to protect the stitches on a fabric being worked in textile machines.

[0002] The invention is applied to textile machines, in particular drum-type raising machines and grinding machines, to protect the transverse stitches used to join the pieces of fabric together so as to achieve a continuous strip to be worked.

[0003] The invention prevents the joining stitches from being subjected to the action of the working elements of the textile machines, thus preventing possible damage and breakages.

BACKGROUND OF THE INVENTION

[0004] In various textile operations the state of the art joins together various pieces of fabric, by means of transverse stitches, to be subjected to treatment in order to achieve a single, continuous strip, in order to increase the productivity of machines performing a continuous, prolonged process.

[0005] This technique, however, has the disadvantage that the zones where the pieces are joined are structurally weak since these stitches, if caught by the working elements of the machine, can be damaged and even torn. If these stitches are broken, this leads to the adjacent pieces becoming separated, and consequently it is necessary to stop the machine to restore the continuity of the strip.

[0006] This disadvantage occurs particular in raising machines or grinding machines, wherein the working cylinders are covered with metal points or abrasive elements which exert an energetic action of removing or abrading the threads of the fabric. In such machines, therefore, the fabric is subjected to mechanical stresses which can cause the stitches between adjacent pieces to break.

[0007] To solve this problem of breaking the stitches, it has been proposed to locate sensors, at least upstream of the drums, which are suitable to detect the arrival of the stitches, and to command the working cylinders to idle.

[0008] This solution has the advantage that it is simple but, on the contrary, it entails discarding many metres of fabric, because some parts of the fabric are not worked; these are of a length substantially equal to almost twice the circumference of the drum of the machine which, in average-size raising and grinding machines, is about three metres.

[0009] There has also been a proposal, in EP 613.972, for a device which uses a protection element consisting of a cusp-shaped bar arranged between the working cylinders and the fabric, and suitable to rotate around the drum of the textile machine. This bar is started by sensors which detect the arrival of the stitches at the machine, and rotates around the drum, keeping the fabric raised in correspondence with the stitch and protecting it from the action of the working cylinders.

[0010] This device has a plurality of disadvantages, including the risk that the bar may come into contact with the linings of the working cylinders, damaging them and itself, the risk that the fabric may tie the bar to the working cylinders, possible damage to the brushes which clean the cylinders, and other problems.

[0011] This device also causes the formation of a considerable section of fabric, in the range of 70ö80 cm, either side of the stitch, which is not raised and which therefore has to be eliminated when the pieces are separated at the end of the process.

[0012] Placing a bar between the working cylinders and the fabric in order to raise the fabric puts tension on the fabric too, with a consequent difference in the raising or grinding effect.

[0013] The present Applicant, in the European patent application EP-A-959.168, described a stitch-saving device comprising a bar which rotates around and outside the raising or grinding drum; this bar includes means to grip and raise the fabric which are made to act when a stitch is about to arrive and prevent the stitch from entering into contact with the surface of the working cylinders. This solution has proved to be very satisfactory and has entailed considerable advantages in raising and grinding operations.

[0014] However, it has been found in this field that there is a need for a device which will achieve the same result, that is, preserving the stitches from the action of the working cylinders, but without needing any further contact with the fabric while it is being worked.

[0015] Moreover, such devices cannot be effectively used on machines with a considerable working height, due to the deflection of the bars.

[0016] The present Applicant has devised and embodied this invention to overcome the shortcomings of the state of the art and to obtain further advantages.

SUMMARY OF THE INVENTION

[0017] The invention is set forth and characterized in the main claims, while the dependent claims describe other characteristics of the main embodiment.

[0018] The purpose of the invention is to provide a device to protect the stitches from the action of the working elements of a drum-type textile machine, which will create minimum impact on the working of the fabric and which will not require a direct action on the fabric to prevent contact between stitches and working elements.

[0019] Another purpose of the invention is to provide a device which can also be employed on existing textile machines without substantially altering the configuration of the machine.

[0020] In accordance with such purposes, the invention provides to use means able to temporarily disconnect the drive to transmit motion only to the working cylinders which are substantially in correspondence with the stitch advancing around the drum of the textile machine.

[0021] To be more exact, the invention provides that, when a stitch arrives, as detected by sensors arranged for the purpose in cooperation with the inlet zone to the drum, rotary means are activated which act, sequentially and selectively, on the means which transmit motion from the drive member to the working cylinders arranged on the circumference of the drum.

[0022] Transmission of motion to the working cylinders is then sequentially de-activated, in coincidence with the passage of the stitch on the cylinders, or of the cylinders on the stitch, and immediately afterwards restarted when the stitch has passed, since the action of de-activating the motion, determined by said rotary means, is stopped.

[0023] The working cylinders rotate idle when the fabric passes due to the drawing action caused by the fabric itself, but they do not exert any energetic action thereon, and therefore there is no risk of ruining and breaking the stitches.

[0024] In one embodiment of the invention, the de-activation means consist of at least a contact element, for example a roller, associated with a rotary bar which supports and moves the roller; this roller is pre-set to be selectively inserted between each pulley which provides motion to a relative working cylinder and the belt means which make said pulleys rotate.

[0025] During its rotation around the drum, said roller lifts the belt and sequentially disconnects the kinematic connection between the belt and the pulleys, causing the momentary interruption of the transmission of motion during the passage of the stitch in coincidence with a specific working cylinder. When the working cylinders, and the relative pulleys, which rotate with the drum at a speed advantageously greater than that of the bar, reach the position wherein the bar itself is found, substantially corresponding to the position of the stitch on the fabric, they find the belt raised, and therefore in that segment the pulley does not receive any command to move from the belt, and the relative cylinder rotates idle to draw the fabric.

[0026] With this invention, which does not require any direct contact with the fabric being worked, we obtain the advantage that we reduce to a minimum the unworked segment either side of the stitch, for segments in the order of only 300ö400 mm.

[0027] Moreover, there is no limit to the working height, so that the device can also be applied on machines which are quite high.

[0028] Furthermore, both the fabric and the drum can be made to rotate without distinction in one direction or another, either clockwise or anti-clockwise. Since the device according to the invention acts on the transmission belt means, not on the fabric, it can make a complete rotation of 360° without interfering in any way with the devices located adjacent and outside the working cylinders, for example the brushes which clean the cylinders.

[0029] In the event that there are obstacles which prevent the complete rotation of the device, it can be made to rotate alternately in one direction and in the other, from inlet to outlet of the fabric and vice versa.

[0030] In the event that the bar is made to return to position with a rotation in the inverse direction, it can be moved at a higher speed, up to 4-5 times, compared to the outward speed, facilitated by the fact that it moves in a direction concordant with the direction of the belts.

[0031] In this way, even if the bar lifts the belts and disconnects the working cylinders from the relative motion transmission members during repositioning, this action of disconnection is very short and therefore has a minimum effect on the raising or grinding action.

[0032] According to a variant, during the inverse movement when the bar is repositioned, a mechanism to displace the contact elements is temporarily activated which eliminates interference thereof with the belt; therefore, the bar can be repositioned without interfering with the action of the working cylinders and remain stationary in a position wherein it waits for the next stitch.

[0033] There can be two, three or more contact elements which act on the belt means, depending on the desired entity of the segment of fabric either side of the stitch which is to be protected.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] These and other advantages of the invention will be apparent from the description of a preferential form of embodiment given with reference to the attached drawings, wherein:

Fig. 1

is a schematic view of a raising or grinding machine equipped with a device to protect the stitches according to the invention;

Fig. 2

shows an enlarged view from A of a detail of Fig. 1.

DETAILED DESCRIPTION OF PREFERENTIAL EMBODIMENT

[0035] Fig. 1 shows schematically a raising or grinding machine 10 equipped with a rotary drum 11, on the circumference of which a plurality of rotary working cylinders 16, 116 are mounted, covered with raising or abrasive material according to the type of machine.

[0036] A continuous fabric 12 is made to pass around said drum 11, and in contact with said working cylinders 16, 116, by means of an inlet drawing element 13 and an outlet drawing element 14; advantageously, said drawing elements 13 and 14 are associated with means to control and regulate the tension of the fabric 12.

[0037] In the lower part of the drum 11 there are means 15 to clean the cylinders 16, 116, in this case consisting of two brushes 15a.

[0038] The rotatory motion is transmitted to the working cylinders by means of at least a drive member 17 connected to a toothed wheel 18 on which transmission belt means 19 are engaged.

[0039] The belt means 19 engage on a plurality of pulleys 20 distributed along the periphery of the drum 11 and able to axially transmit motion to a relative working cylinder (Fig. 2).

[0040] In the case of Fig. 1, said belt means 19 are able to make a first plurality of working cylinders 16, or pile cylinders, rotate simultaneously; the cylinders 16 are arranged in alternation with a second plurality of working cylinders 116, or counterpile cylinders; the counterpile cylinders 116 are made to rotate by a similar mechanism arranged on the opposite side of the drum 11, and hence not visible in Fig. 1.

[0041] The machine 10 also comprises at least a sensor 21, arranged in cooperation with the inlet to the drum 11 and able to detect and signal the arrival of a transverse stitch 22 on the fabric 12.

[0042] The device to protect said stitches 22 is denoted generally by the reference number 23 and comprises a bar 24, arranged radially with respect to the drum 11 and able to support, at its outer end, in this case, two rollers 25 arranged parallel and separated by a segment "1". The distance "1" defines the amplitude of fabric 12 either side the stitch which is protected from the action of the working cylinders 16, 116.

[0043] Said rollers 25 can have a cylindrical surface, or have surface grooves for positioning the belts 19, mating in number to that of said belts 19, in the same way as the pulleys 20.

[0044] It comes within the field of the invention to provide that only one roller 25 is mounted on the bar 24, or three or more rollers 25 defining an overall distance equal to or more than "1", according to the amplitude of fabric 12 in correspondence with a stitch which has to be preserved from the action of the working cylinders 16, 116.

[0045] The inner end of the bar 24 is solidly associated with a toothed crown 26, coaxial with the drum 11 and able to be made to rotate by a reduction gear 27 by means of a command pinion 28. The drive of the reduction gear 27 is governed by the detection, by means of the sensor 21, of the arrival of a stitch 22 at the inlet to the drum 11.

[0046] The device 23 to protect stitches 22 functions as follows: At first, the bar 24 is stationary in a stand-by position 24a, substantially in correspondence with the inlet of the fabric 12 to the drum 11, wherein the relative rollers 25 do not interfere with the belt means 19. This position can be controlled, according to a variant, by a suitable magnetic sensor.

[0047] When the sensor 21 detects the arrival of a stitch 22 in the fabric 12, it sends a signal to activate the reduction gear 27 which begins to make the bar 24 rotate, and make it describe a circumference which has its center of rotation substantially coincident with the center of rotation of the drum 11, and a radius greater than the radius of the drum 11.

[0048] Moreover, the bar 24 has a length such as to extend radially beyond the outer circumference of the pulleys 20 (Fig. 1, positions 24b and 24c). Therefore, during the rotation of the bar 24, the rollers 25 lift the belt means 19 and disengage them, on each occasion and sequentially, from a relative pulley 20 (Fig. 2), momentarily interrupting the transmission of motion to the relative working cylinders 16.

[0049] By suitably synchronizing the axial position of the bar 24, that is, the moment when it is made to rotate and its speed, with the position of the stitch 22 on the fabric 12, we obtain that every working cylinder 16 is sequentially disconnected from its movement members 17, 18 and 19 at the moment the stitch 22 passes on its circumference. Therefore, the working cylinder 16 cannot perform an energetic action on the fabric 12, and risk ruining or breaking the stitch 22, but is only made to rotate idly by the fabric 12, without exerting any effect thereon.

[0050] According to one embodiment of the invention, the bar 24 rotates at a lower speed than the speed of rotation of the drum 11 around its axis, and hence the speed at which the pulleys 20 rotate around said axis of rotation of the drum 11. When the bar 24 starts to rotate, moving substantially into correspondence with the stitch, it lifts the relative belts 19 and keeps them raised for the whole of its rotation. One by one the pulleys 20, rotating with the drum 11 more quickly than the bar 24, come to find themselves sequentially in the zone corresponding to the stitch, wherein the belts 19 are raised and therefore, in that segment either side the stitch, they do not receive any command to move from said belts 19.

[0051] In the segment when there is no contact with the belts 19, the pulleys 20 are kept in rotation only due to the drawing effect of the fabric 12 advancing with the relative working cylinders 16, 116.

[0052] It has to be considered that the difference in the number of revolutions between the cylinders commanded by the belts 19 and the cylinders drawn due to the drawing effect of the fabric 12 is about 70ö100 revolutions, therefore, in this second case, any damaging effect on the stitches of the fabric is considerably reduced.

[0053] In this way, the action of the working cylinders 16 on the stitches 22 is prevented, safeguarding their wholeness and preventing tears and damage. The zone either side of the stitches 22 which is not worked is limited to the minimum, by acting on the number of, and reciprocal distance between, the rollers 25. Moreover, the action to protect the stitches 22 does not entail any direct action on the fabric 12 being worked, and in particular it does not exert any increase or decrease in the tension thereof.

[0054] To compensate the lengthening caused by the continuous lifting of the belt means 19, the pulley 18 is displaced in coordinated fashion by means of a lever 29 driven by a pneumatic command 30 in order to keep the tension of said belt means 19 substantially constant.

[0055] Obviously, an analogous device 23 is provided on the opposite side of the machine 10 to act on the mating counterpile cylinders 116.

[0056] Modifications or additions of parts may be made to the device as described heretofore, without departing from the scope of the invention.

[0057] For example, a mechanism (not shown here) may be provided to displace, lower or rotate the rollers 25 to a position of non-interference with the belt means 19, in order to reposition the bar 24 in the stand-by position 24a, rotating it in the opposite direction, without disconnecting motion to the working cylinders 16, 116.

Claims

1. Device to protect stitches (22) on a fabric (12) being worked in textile machines (10) equipped with at least a rotary drum (11) on the periphery of which a plurality of rotary working cylinders (16, 116) are assembled, characterized in that it includes means (24, 25) selectively rotating and able to temporarily disconnect the drive to transmit rotatory motion only to the working cylinders (16, 116) which are substantially in correspondence with one of said stitches (22) advancing around said drum (11).

2. Device as in claim 1, characterized in that said means (24, 25) are able to rotate along a circumference having as its center of rotation substantially the center of rotation of said drum (11).

3. Device as in claim 1 or 2, characterized in that said means comprise at least a contact element (25) associated with bar means (24) to support and move said contact element (25), said contact element (25) being able to act selectively and sequentially on the means which make said working cylinders (16, 116) rotate, in order to disconnect the kinematic connection from said cylinders (16, 116) during the passage of said stitches (22) in correspondence therewith.

4. Device as in claim 1, wherein the means to transmit motion to the working cylinders (16, 116) comprise belt means (19) and a plurality of pulleys (20) distributed along the periphery of said drum (11), each of said pulleys (20) being associated with at least a relative working cylinder (16, 116), characterized in that said contact element consists of at least a roller (25) able to be selectively inserted between said belt means (19) and each of said pulleys (20) to disconnect the kinematic connection between them and to momentarily interrupt the transmission of motion to the relative working cylinder (16, 116).

5. Device as in claim 4, characterized in that said roller (25) is associated with the terminal part of bar means (24), said bar means (24) having a length greater than the diameter of said drum (11).

6. Device as in claim 4, characterized in that said contact element comprises two or more rollers (25) arranged separated from each other by a distance "1" correlated to the desired segment of fabric (12), either side the stitch (22), to be preserved from the action of the working cylinders (16, 116).

7. Device as in claim 4, characterized in that said rollers (25) have a substantially cylindrical surface.

8. Device as in claim 4, characterized in that said rollers (25) have grooves on the surface, mating in number to that of said belts (19).

9. Device as in claim 1, characterized in that said means (24, 25) include a first position (24a) wherein they await the arrival of said stitch (22), substantially in proximity with the inlet of the fabric (12) to said drum (11), wherein they do not interfere with the drive to transmit motion to said working cylinders (16, 116).

10. Device as in any claim hereinbefore, wherein said machines (10) include sensor means (21) located in cooperation with the zone of inlet to said drum (11) and suitable to detect the arrival of a stitch (22) at the machine, characterized in that said bar means (24) are able to be made to rotate by means of drive means (26, 27, 28) the selective activation of which is governed by the detection, by said sensor means (21), that a stitch (22) is arriving in correspondence with the inlet to said drum (11).

11. Device as in claim 10, characterized in that said bar means (24) are able to be made to rotate through 360° around said drum (11) and substantially at the same peripheral speed of said fabric (12).

12. Device as in claim 10, characterized in that said bar means (24) are able to be made to rotate, substantially at the same peripheral speed as said fabric (12), from the inlet zone of the fabric (12) to said drum (11) to the outlet zone of said fabric (12) from said drum (11), and to then make an inverse rotation in order to return in correspondence with said inlet zone.

13. Device as in claim 12, characterized in that during said inverse rotation, said bar means (24) are able to rotate at a greater speed than the speed assumed during the rotation from the inlet zone to the outlet zone of said fabric (12) from said drum (11).

14. Device as in claim 12, characterized in that it comprises a mechanism able to displace said rollers (25) to a position of non-interference with said belt means (19) during said inverse rotation of re-positioning said bar means (24) to a stand-by position (24a).

15. Device as in claim 4, characterized in that said belt means (19) cooperate with tensioning and compensation means (29, 30).

16. Method to protect stitches (22) on a fabric (12) being worked in textile machines (10) equipped with at least a rotary drum (11) on the periphery of which a plurality of rotary working cylinders (16, 116) are assembled, wherein said machines (10) include sensor means (21) located in cooperation with the inlet zone to said drum (11) and suitable to detect the arrival of a stitch (22) at the machine (10), characterized in that, when said stitch (22) arrives in correspondence with the inlet to said drum (11), it provides to activate a device (23) rotating on a circumference having as its center of rotation substantially the center of rotation of said drum (11) and including means (24, 25) able to temporarily and selectively disconnect the drive to transmit rotatory motion only to the working cylinders (16, 116) which are in correspondence with said stitch (22) advancing around said drum (11).

17. Method as in claim 16, characterized in that it provides to make said means (24, 25) follow a circumference having as its center of rotation substantially the center of rotation of said drum (11) and a radius greater than the radius of said drum (11), so that during their rotation said means (24, 25) can sequentially interrupt the transmission of motion to at least one working cylinder (16, 116) at the moment said stitch (22) passes thereon, said transmission of motion to the working cylinders (16, 116) being automatically restored as soon as said means (24, 25) move from one cylinder (16, 116) to the adjacent one.

18. Method as in claim 16 or 17, characterized in that it provides that said means (24, 25) rotate around said drum (11) substantially at the same peripheral speed as said fabric (12).

19. Method as in claim 16, characterized in that it provides to make said means (24, 25) follow a rotation of 360° around said drum (11).

20. Method as in claim 16, characterized in that it provides to make said means (24, 25) make an alternate rotation in one direction and the other around said drum (11) from the inlet zone of said fabric (12) to the outlet zone.

21. Method as in claim 16, characterized in that said fabric (12) and/or said drum (11) can be made to rotate irrespectively in one direction or the other, clockwise or anti-clockwise.

Ansprüche

1. Vorrichtung zum Schützen von Stichen (22) an einem Gewebe (12), das in Textilmaschinen (10) bearbeitet wird, die mit mindestens einer rotierenden Trommel (11) versehen sind, an deren Umfang mehrere rotierende Arbeitszylinder (16, 116) angebaut sind, dadurch gekennzeichnet, dass sie über eine sich selektiv drehende Einrichtung (24, 25) verfügt, die den Antrieb zeitweilig unterbrechen kann, um eine Drehbewegung nur auf diejenigen Arbeitszylinder (16, 116) zu übertragen, die im Wesentlichen einem der Stiche (22) entsprechen, die um die Trommel (11) herum weitergeführt werden.

2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass sich die Einrichtung (24, 25) entlang einem Umfang drehen kann, der als Rotationszentrum im Wesentlichen das Rotationszentrum der Trommel (11) aufweist.

3. Vorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Einrichtung mindestens ein Kontaktelement (25) aufweist, dem eine Stabeinrichtung (24) zum Halten und Bewegen des Kontaktelements (25) zugeordnet ist, wobei das Kontaktelement (25) selektiv und sequenziell auf die Einrichtung einwirken kann, die dafür sorgt, dass sich die Arbeitszylinder (16, 116) drehen, um die kinematische Verbindung von diesen Zylindern (16, 116) während des Durchlaufs der Stiche (22) entsprechend zu diesen zu trennen.

4. Vorrichtung nach Anspruch 1, bei der die Einrichtung zum Übertragen einer Bewegung an die Arbeitszylinder (16, 116) eine Riemeneinrichtung (19) und mehrere Riemenscheiben (20) aufweist, die entlang dem Umfang der Trommel (11) verteilt sind, wobei jede der Riemenscheiben (20) mindestens ein zugehöriger Arbeitszylinder (16, 116) zugeordnet ist, dadurch gekennzeichnet, dass das Kontaktelement aus mindestens einer Rolle (25) besteht, die selektiv zwischen die Riemeneinrichtung (19) und jede der Riemenscheiben (20) eingeführt werden kann, um die kinematische Verbindung zwischen ihnen zu trennen und die Übertragung der Bewegung an den zugehörigen Arbeitszylinder (16, 116) momentan zu unterbrechen.

5. Vorrichtung nach Anspruch 4, dadurch gekennzeichnet, dass die Rolle (25) dem Abschlussteil einer Stabeinrichtung (24) zugeordnet ist, die über eine Länge verfügt, die größer als der Durchmesser der Trommel (11) ist.

6. Vorrichtung nach Anspruch 4, dadurch gekennzeichnet, dass das Kontaktelement zwei oder mehr Rollen (25) aufweist, die um einen Abstand "1", der mit dem gewünschten Segment eines Gewebes (12) korreliert ist, getrennt voneinander auf einer jeweiligen Seite des Stichs (22) angeordnet sind, um gegen die Wirkung der Arbeitszylinder (16, 116) geschützt zu sein.

7. Vorrichtung nach Anspruch 4, dadurch gekennzeichnet, dass die Rollen (25) eine im Wesentlichen zylindrische Oberfläche aufweisen.

8. Vorrichtung nach Anspruch 4, dadurch gekennzeichnet, dass die Rollen (25) in der Oberfläche Rillen aufweisen, deren Anzahl zu der der Riemen (19) passt.

9. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass die Einrichtung (24, 25) über eine erste Position (24a) verfügt, in der sie auf das Eintreffen des Stichs (22), im Wesentlichen in der Nähe des Einlasses des Gewebes (12) zur Trommel (11), wartet, wobei sie den Antrieb zum Übertragen einer Bewegung an die Arbeitszylinder (16, 116) nicht behindert.

10. Vorrichtung nach einem der vorstehenden Ansprüche, bei der die Maschinen (10) eine Sensoreinrichtung (21) aufweisen, die in Zusammenwirkung mit der Einlasszone zur Trommel (11) vorhanden ist, und das Eintreffen eines Stichs (22) an der Maschine erkennen kann, dadurch gekennzeichnet, dass dafür gesorgt werden kann, dass sich die Stabeinrichtung (24) durch eine Antriebseinrichtung (26, 27, 28) dreht, deren selektive Aktivierung durch die Erkennung, durch die Sensoreinrichtung (21), gesteuert wird, dass ein Stich (22) entsprechend zum Einlass zur Trommel (11) eintrifft.

11. Vorrichtung nach Anspruch 10, dadurch gekennzeichnet, dass dafür gesorgt werden kann, dass sich die Stabeinrichtung (24) um 360° um die Trommel (11) und im Wesentlichen mit derselben Umfangsgeschwindigkeit wie der des Gewebes (12) dreht.

12. Vorrichtung nach Anspruch 10, dadurch gekennzeichnet, dass dafür gesorgt werden kann, dass sich die Stabeinrichtung (24) im Wesentlichen mit derselben Umfangsgeschwindigkeit wie das Gewebe (12) von der Einlasszone des Gewebes (12) zur Trommel (11) zur Auslasszone des Gewebes (12) von der Trommel (11) dreht, und dass sie dann eine umgekehrte Drehung ausführt, um entsprechend zur Einlasszone zurückzukehren.

13. Vorrichtung nach Anspruch 12, dadurch gekennzeichnet, dass sich die Stabeinrichtung (24) während der umgekehrten Drehung mit einer größeren Geschwindigkeit drehen kann, als sie während der Drehung von der Einlasszone zur Auslasszone des Gewebes (12) von der Trommel (11) eingenommen wird.

14. Vorrichtung nach Anspruch 12, dadurch gekennzeichnet, dass sie einen Mechanismus aufweist, der die Rollen (25) während der umgekehrten Drehung zur Neupositionierung der Stabeinrichtung (24) in einer Bereitschaftsposition (24a) in eine Position verschieben kann, in der keine Wechselwirkung mit der Riemeneinrichtung (19) besteht.

15. Vorrichtung nach Anspruch 4, dadurch gekennzeichnet, dass die Riemeneinrichtung (19) mit einer Spann- und Kompensationseinrichtung (29, 30) zusammenwirkt.

16. Verfahren zum Schützen von Stichen (22) an einem Gewebe (12), das in Textilmaschinen (10) bearbeitet wird, die mit mindestens einer rotierenden Trommel (11) versehen sind, an deren Umfang mehrere rotierende Arbeitszylinder (16, 116) angebaut sind, wobei die Maschinen (10) eine Sensoreinrichtung (21) aufweisen, die in Zusammenwirkung mit der Einlasszone zur Trommel (11) vorhanden ist und die das Eintreffen eines Stichs (22) an der Maschine (10) erkennen kann, dadurch gekennzeichnet, dass dann, wenn der Stich (22) entsprechend dem Einlass zur Trommel (11) eintrifft, dadurch eine Vorrichtung (23) aktiviert wird, die sich auf einem Umfang dreht, der als Rotationszentrum im Wesentlichen das Rotationszentrum der Trommel (11) aufweist, und mit einer Einrichtung (24, 25) zum zeitweiligen und selektiven Trennen des Antriebs zum Übertragen einer Drehbewegung nur an diejenigen Arbeitszylinder (16, 116), die entsprechend zum Stich (22) vorhanden sind, der um die Trommel (11) herum weitergeführt wird.

17. Verfahren nach Anspruch 16, dadurch gekennzeichnet, dass es dafür sorgt, dass die Einrichtung (24, 25) einem Umfang folgt, der als Rotationszentrum im Wesentlichen das Rotationszentrum der Trommel (11) aufweist und über einen Radius verfügt, der größer als der Radius der Trommel (11) ist, so dass die Einrichtung (24, 25) während ihrer Drehung die Übertragung einer Bewegung an mindestens einen Arbeitszylinder (16, 116) zum Zeitpunkt, zu dem der Stich (22) daran vorbei läuft, sequenziell unterbrechen kann, wobei die Übertragung der Bewegung an die Arbeitszylinder (16, 116) automatisch wiederhergestellt wird, sobald sich die Einrichtung (24, 25) von einem Zylinder (16, 116) zum benachbarten bewegt.

18. Verfahren nach Anspruch 16 oder 17, dadurch gekennzeichnet, dass es dafür sorgt, dass sich die Einrichtung (24, 25) mit im Wesentlichen derselben Umfangsgeschwindigkeit wie das Gewebe (12) um die Trommel (11) dreht.

19. Verfahren nach Anspruch 16, dadurch gekennzeichnet, dass es dafür sorgt, dass die Einrichtung (24, 25) einer Drehung von 360° um die Trommel (11) folgt.

20. Verfahren nach Anspruch 16, dadurch gekennzeichnet, dass es dafür sorgt, dass die Einrichtung (24, 25) eine abwechselnde Umdrehung in einer Richtung und der anderen um die Trommel (11) von der Einlasszone des Gewebes (12) zur Auslasszone ausführt.

21. Verfahren nach Anspruch 16, dadurch gekennzeichnet, dass dafür gesorgt werden kann, dass sich das Gewebe (12) und/oder die Trommel (11) unabhängig in der einen Richtung oder der anderen, in der Uhrzeigerrichtung oder dagegen, drehen.

Revendications

1. Dispositif pour protéger des piqûres (22) sur un tissu (12) en phase d'usinage dans des machines textiles (10) dotées d'au moins un tambour rotatif (11) à la périphérie duquel on a assemblé une pluralité de cylindres travailleurs (16, 116) rotatifs, caractérisé en ce qu'il présente des moyens (24, 25) sélectivement rotatifs et .aptes à ne débrancher temporairement la commande de transmission du mouvement rotatoire qu'aux cylindres travailleurs (16, 116) qui se trouvent substantiellement à proximité d'une desdites piqûres (22) s'avançant autour dudit tambour (11).

2. Dispositif selon la revendication 1, caractérisé en ce que lesdits moyens (24, 25) sont aptes à tourner le long d'une circonférence ayant comme son propre centre de rotation substantiellement le centre de rotation dudit tambour (11).

3. Dispositif selon la revendication 1 ou 2, caractérisé en ce que lesdits moyens comprennent au moins un élément de contact (25) associé à des moyens à barre (24) de soutien et manutention dudit élément de contact (25), ledit élément de contact (25) étant apte à agir sélectivement et séquentiellement sur les moyens qui entraînent la rotation desdits cylindres travailleurs (16, 116) pour débrancher la connexion cinématique aux dits cylindres (16, 116) pendant le passage desdites piqûres (22) à proximité des cylindres en question.

4. Dispositif selon la revendication 1, où les moyens de transmission du mouvement aux cylindres travailleurs (16, 116) comprennent des moyens à courroie (19) et une pluralité de poulies (20) distribuées le long de la périphérie dudit tambour (11), chacune desdites poulies (20) étant associée à au moins un cylindre travailleur y afférent (16, 116) caractérisé en ce que ledit élément de contact se compose d'au moins un rouleau (25) apte à s'insérer sélectivement entre lesdits moyens à courroie (19) et chacune desdites poulies (20) pour débrancher la connexion cinématique entre eux et couper temporairement la transmission du mouvement au cylindre travailleur y afférent (16, 116).

5. Dispositif selon la revendication 4, caractérisé en ce que ledit rouleau (25) est associé à la partie terminale de moyens à barre (24), lesdits moyens à barre (24) présentant une longueur supérieure au diamètre dudit tambour (11).

6. Dispositif selon la revendication 4, caractérisé en ce que ledit élément de contact comprend deux ou plusieurs rouleaux (25) aménagés entre eux écartés d'une distance « 1 » en relation à la portion de tissu voulue (12), à cheval de la piqûre (22), à préserver de l'action des cylindres travailleurs (16, 116).

7. Dispositif selon la revendication 4, caractérisé en ce que lesdits rouleaux (25) présentent une surface substantiellement cylindrique.

8. Dispositif selon la revendication 4, caractérisé en ce que lesdits rouleaux (25) présente des gorges dans sa surface, à un nombre conjugué au nombre desdites courroies (19).

9. Dispositif selon la revendication 1, caractérisé en ce que lesdits moyens (24, 25) présentent une première position (24a) où ils attendent la venue de ladite piqûre (22), substantiellement à proximité de l'entrée du tissu (12) dans ledit tambour (11), où ils n'interfèrent pas avec la commande de transmission du mouvement aux dits cylindres travailleurs (16, 116).

10. Dispositif selon l'une ou l'autre revendication précédente, où lesdites machines (10) présentent des moyens capteurs (21) aménagés en coopération avec la zone d'entrée dans ledit tambour (11) et aptes à détecter la venue à la machine d'une piqûre (22), caractérisé en ce que lesdits moyens à barre (24) sont aptes à qu'on les fasse tourner par des moyens d'actionnement (26, 27, 28) dont le démarrage sélectif est subordonné à la détection, par lesdits moyens capteurs (21), de la venue d'une piqûre (22) à proximité de l'entrée dudit tambour (11).

11. Dispositif selon la revendication 10, caractérisé en ce que lesdits moyens à barre (24) sont aptes à qu'on les fasse tourner de 360° autour dudit tambour (11) et substantiellement à la même vitesse périphérique dudit tissu (12).

12. Dispositif selon la revendication 10, caractérisé en ce que lesdits moyens à barre (24) sont à aptes à qu'on les fasse tourner, substantiellement à la même vitesse périphérique dudit tissu (12), de la zone d'entrée du tissu (12) sur ledit tambour (11) à la zone de sortie dudit tissu (12) dudit tambour (11), et à effectuer ensuite une rotation inverse pour remonter à proximité de ladite zone d'entrée.

13. Dispositif selon la revendication 12, caractérisé en ce que pendant ladite rotation inverse, lesdits moyens à barre (24) sont aptes à tourner à une vitesse supérieure par rapport à la vitesse prise tout au long de la rotation de la zone d'entrée à la zone de sortie dudit tissu (12) dudit tambour (11).

14. Dispositif selon la revendication 12, caractérisé en ce qu'il comprend un mécanisme apte à déplacer lesdits rouleaux (25) dans une position de non interférence avec lesdits moyens à courroie (19) pendant ladite rotation inverse de repositionnement desdits moyens à barre (24) dans une position d'attente (24a).

15. Dispositif selon la revendication 4, caractérisé en ce que lesdits moyens à courroie (19) coopèrent avec des moyens de tension et de compensation (29, 30).

16. Procédé pour protéger les piqûres (22) sur un tissu (12) en phase d'usinage dans des machines textiles (10) dotées d'au moins un tambour rotant (11) à la périphérie duquel on a assemblé une pluralité de cylindres travailleurs (16, 116) rotatifs, où lesdites machines (10) présentent des moyens capteurs (21) aménagés en coopération avec la zone d'entrée dans ledit tambour (11) et aptes à détecter la venue à la machine (10) d'une piqûre (22), caractérisé en ce que, lorsque ladite piqûre (22) arrive à proximité de l'entrée dudit tambour (11), il prévoit de démarrer un dispositif (23) rotatif sur une circonférence ayant comme son propre centre de rotation substantiellement le centre de rotation dudit tambour (11) et présentant des moyens (24, 25) aptes à ne débrancher, temporairement et sélectivement, la commande de transmission du mouvement de rotation qu'aux cylindres travailleurs (16, 116) qui se trouvent à proximité de ladite piqûre (22) s'avançant autour dudit tambour (11).

17. Procédé selon la revendication 16, caractérisé en ce qu'il prévoit de faire parcourir aux dits moyens (24, 25) une circonférence ayant comme son propre centre de rotation substantiellement le centre de rotation dudit tambour (11) et un rayon supérieur au rayon dudit tambour (11), afin que lesdits moyens (24, 25), pendant leur rotation, puissent couper séquentiellement la transmission du mouvement à au moins un cylindre travailleur (16, 116) lors du passage de ladite piqûre (22) sur ce dernier, ladite transmission dudit mouvement aux cylindres travailleurs (16, 116) étant automatiquement rétablie dès que lesdits moyens (24, 25) se déplacent d'un cylindre (16, 116) au cylindre contigu.

18. Procédé selon la revendication 16 ou 17, caractérisé en ce qu'il prévoit que lesdits moyens (24, 25) tournent autour dudit tambour (11) substantiellement à la même vitesse périphérique dudit tissu (12).

19. Procédé selon la revendication 16, caractérisé en ce qu'il prévoit de faire parcourir aux dits moyens (24, 25) une rotation de 360° autour dudit tambour (11).

20. Procédé selon la revendication 16, caractérisé en ce qu'il prévoit de faire parcourir aux dits moyens (24, 25) une rotation dans les deux directions alternativement autour dudit tambour (11) de la zone d'entrée dudit tissu (12) à la zone de sortie.

21. Procédé selon la revendication 16, caractérisé en ce qu'il prévoit qu'on puisse faire tourner ledit tissu (12) et/ou ledit tambour (11) indifféremment dans l'une ou l'autre direction, dans le sens des aiguilles d'une montre ou dans le sens inverse à celui des aiguilles d'une montre.

Drawing