DRIVESYSTEM FOR WEAVING LOOMS

Abstract: Transmission for weaving looms characterized by the fact that it is composed of the combination of a main transmission (1), of an auxiliary transmission (2), of a main shaft (3), of an auxiliary shaft (4), a shot search coupling (5) that achieves connectable and disconnectable connection between the main shaft (3) and the auxiliary shaft (4) whereby the connection may occur with a large number of mutually different positions of the main shaft (3) and of the auxiliary shaft (4) in function of a set value for the angular difference.

Description: The present invention concerns a drive system for weaving looms of any kind. More particularly, the invention concerns a drive system comprising a shot search coupling which makes possible to achieve a connection between the auxiliary shaft and the main shaft, whereby this connection between these shafts can occur with a large number of different positions and automatically in function of a previously adjustable parameter. The wording "main shaft" is related in this case as already known, to the shaft which is mainly driving the batten and, in the case of a gripper weaving loom, is also driving the gripper. The main shaft rotates at the same speed as the weaving loom. The wording "auxiliary shaft" means, in this case, as already known, the shaft which is driving the weaving loom parts which are rotating at half speed. The auxiliary shaft is mainly driving the frames in this case. Drive systems of the abovesaid type are known from US 4.424.835 and US 4.474.219. The drive systems as disclosed in these documents show however the disadvantage that it is rather difficult to modify the crossing moment of the weaving frames in relationship to the movement of the batten. The present invention is designed to achieve a drive system whereby the crossing moment of the weaving frames can relatively easily be modified in relationship to the beating moment of the batten, whereby such operation takes place automatically in function of the adjustment carried out by the weaver after having considered the aspect of the woven cloth. It is indeed already known that the crossing moment related to the beating moment of the batten is a decisive factor in weaving looms as far as the aspect of the woven cloth is concerned. Consequently, it is necessary to be able to adjust these values, whereby fine adjustment should be preferably possible. According to a well-known method, the auxiliary shaft of the weaving loom which is mainly driving the frames, as already reported, and the main shaft which is mainly driving the batten, can manually be adjusted in order to modify the crossing moment. This operation is achieved, for instance, by means of a belt pulley or of a gear wheel which is rotated in relation with the shaft after loosening the clamp connection or, for instance, to shift a toothed-belt over a few teeth or, in the case, of a gear transmission, to shift the toothed gears over a few teeth in relationship to each other and to get them engaged afterwards. Quite obviously this method implies time losses for these mounting and assembling operations. It is also well known that, for shot search couplings, methods are designed, whereby the main shaft and the auxiliary shaft are always engaging each other without erroneous mutual rotation. To this end, clutch couplings are used which make coupling possible only for a specific mutual position of the main shaft and of the auxiliary shaft. Quite obviously, such shot search couplings have the disadvantage that they don't make possible to automatically adjust the crossing moment of the frames. The objective of the present invention is thus to foresee a drive system for weaving loom, whereby the crossing moment can be modified in relationship with the beating movement of the batten and whereby this occurs according to the invention by means of the fully automatic switching-on of the shot search coupling in function of a set value. Another objective of the invention comprises the fact that the shaft whereon the coupling element of the shot search coupling is mounted must not necessarily rotate at the weaving loom speed or the shaft speed. According to a preferred embodiment of the invention, the coupling element of the shot search coupling is mounted on a shaft which is normally rotating at a larger speed than the speed of the main shaft. This system is advantageous because, owing to the larger speed of the coupling element, a smaller rotation moment must be applied to this latter one. Still another advantage of this embodiment whereby the coupling element of the shot search coupling is rotating at a larger speed than the main shaft is related to the fact that such a shot search coupling system is specially suitable to achieve the automation reported hereabove. To this end, the drive system for weaving looms in accordance with the invention comprises at least one drive, a main shaft, an auxiliary shaft and a shot search coupling that can achieve the connection or disconnection between the main shaft and the auxiliary shaft, characterized in that the connection can occur for a large number of mutually different positions of the main shaft and of the auxiliary shaft; and in that said system further comprises detection means for determining the angular difference between the positions of the main shaft and of the auxiliary shaft, and a control unit that controls the shot search coupling and at least one drive for driving the main and/or auxiliary shafts in order to create an automatic connection between the main shaft and the auxiliary shaft in function of a set value for the angular difference. The shot search coupling used to this end will preferably be equipped with a coupling element that is mounted on a shaft rotating at a larger speed, than the main shaft and the auxiliary shaft. To this end, the shot search coupling will be preferably composed of a coupling element, the first part of which is connected by means of a first transmission with the main shaft of the weaving loom and the second part of which is connected by means of a second transmission with the auxiliary shaft, whereby the transmission ratios of both transmissions are chosen in such a way that the coupling element has a larger working speed than the working speeds of the main shaft and of the auxiliary shaft. Quite obviously, owing to the fact that the coupling element is running a larger number of revolutions than the main shaft and the auxiliary shaft, the advantage is achieved that a large number of selections for the mutual connection of the main shaft and of the auxiliary shaft are made possible also if the aforesaid coupling element is made of a clutch coupling that has an inherently limited number of gripping capabilities. The main drive and the auxiliary drive will be preferably mounted respectively along both sides of the coupling element. This way a central location of both drives is obtained between the aforesaid first and second transmissions. Such a central position is advantageous because the main drive, the auxiliary drive, the coupling element of the shot search coupling, and possibly a brake can be included within one single assembly. To this end an electro-magnetic coupling can be used for achieving the necessary mutual connections between the various parts. Such a coupling is described in a separate patent application of the applicant. In order to achieve better understanding of the characteristics of the invention a few preferred embodiments will be described hereafter by way of examples without any limitative character and with reference to the figures in appendix, in which: figure 1 shows a schematic view of a drive system in accordance with the invention; figure 2 is a view of an embodiment of the invention whereby the main drive and the auxiliary drive, as well as the coupling element of the shot search coupling are mounted on a shaft that is rotating at a larger speed than the main shaft and the auxiliary shaft; figure 3 illustrates an alternative solution of the drive system in accordance with the invention; figure 4 illustrates still another alternative solution of the drive system in accordance with the invention; figure 5 is a magnification of a part of figure 4 which is indicated by F5; figure 6 is a cross-section following the line VI-VI of figure 5. As illustrated on the figures, the drive system for weaving looms is mainly composed of a main drive 1, of an auxiliary drive 2, of a main shaft 3 that is driving the batten and possibly the gripper transmission in the case of a gripper weaving loom, an auxiliary shaft 4 that is driving the frames and a shot search coupling 5. The shot search coupling 5 renders possible to disconnect the main shaft 3 and the auxiliary shaft 4 while the frames can be moved only by means of the auxiliary shaft 4 that is driven by the auxiliary drive 2. According to the present invention a shot search coupling 5 is used which makes possible to achieve mutual connection of the main shaft 3 and of the auxiliary shaft 4 following a large number of different mutual angular positions, whereby, as schematically illustrated on figure 1, switching-on is automatically achieved by means of a control unit 6 and in such a way that the shot search coupling 5 is achieving the connection between the main shaft 3 and the auxiliary shaft 4 in function of a set value. As illustrated on figures 1 to 4, detection means, respectively 7 and 8, are mounted to this end on the main shaft 3 and the auxiliary shaft 4, and are composed for instance of angle meters. The data from these detection means 7 and 8 are supplied through the measuring lines 9 and 10 to the control unit 6. On the other hand, control lines 11 and 12 are running from the control unit 6 to, on the one hand, the auxiliary drive 2 and possibly the main drive 1 and, on the other hand, to a switching-on mechanism which is not illustrated on the figures for switching-on or off the coupling element 13, properly speaking, of the shot search coupling 5. Moreover, a setting signal 14 can be also applied to the control unit 6 whereby this signal is indicating the desirable difference between the positions of the main shaft 3 and of the auxiliary shaft 4 at the moment of the next switching-on of the shot search coupling 5. The functioning of the drive system in accordance with the invention occurs mainly as described hereafter. If in case of break of a weft or chain thread the machine is stopped on a known manner and the defective thread is pulled from the shed. Quite obviously, the ratio shall be interrupted this way if an unadequate adjustment of the weaving loom is carried out. To this end and as already known, the coupling element 13 is switched off and the auxiliary shaft is kept rotating by means of the auxiliary drive 2 until the appropriate weft thread is introduced at the right time into the shed, in other words the auxiliary shaft is brought to the correct position towards the main shaft. According to the present invention an angle is set on the control unit 6 and the auxiliary drive 2 will be automatically kept switched on by means of this control unit 6 until the correct switching condition is obtained whereby this result is achieved by means of the measurements which are carried out by the detection means 7 and 8. At the moment that the right mutual position of the main shaft 3 and of the auxiliary shaft 4 is achieved, the coupling element 13 is automatically switched-on. Quite obviously, the use of a shot search coupling 5 that makes possible to mutually connect the main shaft 3 and the auxiliary shaft 4 according to a large number of different mutual positions and, on the other hand, the use of a control unit 6 renders superfluous the manual adjustments with the advantage that the crossing moment of the frames can easily be modified in relationship to the beating moment. Figures 2 to 6 are illustrating by way of examples a few preferred embodiments of drive systems equipped with shot search couplings 5, which are particularly suitable for establishing an automatic connection with a large number of positions and which still have a lot of different other advantages. The shot search coupling 5 which is considered in this case is mainly composed of a coupling element 13 the first part 15 of which is connected to the main shaft 3 by means of a first transmission 16 and the second part 17 of this coupling element 13 is connected with the auxiliary shaft 4 by means of a second transmission 18 whereby the transmission ratios of both transmissions are chosen in such a way that, when the coupling element 13 is switched-on, the latter one will run at a larger speed than the speeds of the main shaft 3 and of the auxiliary shaft 4. The transmission ratios 16 and 18 will be generally chosen respective to each other in such a way that, as already known, the main shaft 3 is rotating in the normal working conditions of the weaving loom at a speed which is twice as large as the revolution speed of the auxiliary shaft 4. In the embodiment according to figure 2, the coupling element 13 is mounted on the shaft 19 that is made of two shaft parts 20 and 21, which are equipped on their ends facing each other of the aforesaid first and second part, respectively 15 and 17 of the coupling element 13. The main drive 1 and the auxiliary drive 2 are respectively mounted on the shaft parts 20 and 21 and in such a way that they are located between the corresponding coupling parts, respectively 15 and 17, and the transmissions 16 and 18. This way, we get the advantage that the whole system made of the drives 1 and 2 and of the coupling element 13 can be designed as a compact assembly 22. Another advantage is related to the fact that the drives 1 and 2 are centrally mounted between the main shaft 3 and the auxiliary shaft 4 whereby the number of couplings in the transmissions is kept limited. The aforesaid assembly 22 may be equipped preferably of an electro-magnetic coupling which makes possible that either the main drive 1 or the auxiliary drive 2 or a brake not illustrated on the figures can be switched on. The transmission 18 is composed in the embodiment according to figure 2 of the combination of a gear coupling 23 comprising two conical gears 24 and 25 and a belt transmission 26. The aforesaid coupling element 13 is made in this case, for instance, of a clutch coupling which has a relatively large number of gripping elements. The functioning of the drive system in accordance with figure 2 includes that, in case of break of thread, the main drive 1 is switched-off, and the aforesaid thread is actuated. This way, the main shaft, as well as the auxiliary shaft are set within a short time. Then the coupling element 13 is disconnected and the defective thread is eliminated. When the weaving loom is switched-on again, the shaft part 21 is first rotated back by means of the auxiliary drive 2 in such a way that the auxiliary shaft 4 is brought to a position corresponding to the set value supplied to the control unit. Such is automatically occurring by means of the detectors 7 and 8 and of the control unit 6. Afterwards, the control unit 6 causes the switching-off of the auxiliary drive 2, the switching-on of the coupling element 13 and finally the switching-on of the main drive 1. Quite obviously, the term auxiliary drive 2 means a drive designed to achieve slow running of the weaving loom. It is also obvious that, in the case of a shot search coupling 5, as illustrated on figure 2, the coupling element 13 is running a larger number of revolutions compared with the main shaft 3 and the auxiliary shaft 4. This gives the advantage that the main shaft 3 and the auxiliary shaft 4 can be connected to each other with a large number of possibilities and that this embodiment is particularly suitable for achieving an automated drive system. Figure 3 is illustrating an alternative solution of the embodiment according to figure 2. In this case, the transmission 18 is made, on the one hand, of a conventional gear transmission while, on the other hand, the main drive 1 and the auxiliary drive 2 are mounted in a common system and can co-operate with the shaft part 21. The main drive 1 and the auxiliary drive 2 can be implemented on quite different ways. According to a preferred embodiment, these elements are made of a given number of coupling parts, of an electro-magnetic coupling, whereby a brake is also foreseen and whereby separate coupling parts are used for the main drive 1 and for the auxiliary drive 2, these parts being respectively connected to a main motor and to an auxiliary motor. Quite obviously, the main drive 1 and the auxiliary drive 2, according to the embodiment of figure 3, can be also made of a motor running at the normal speed, as well as at the slow-run speed, whereby brake actuation can also be foreseen. The working of the drive system according to figure 3 is essentially similar to that of figure 2 and can also easily be understood by looking at the figure. Figure 4 is illustrating still another alternative solution of the drive system in accordance with the invention, whereby the coupling element 13 is cooperating with a gear 27 of the aforesaid transmission 16. As illustrated in details of figures 5 and 6 the shaft 19 is equipped with a threaded end 28 in such a way that the gear 27 can be axially shifted towards the end 28 by means of an adequate notch 29. The connection and the disconnection of the coupling element 13 are achieved in this case, for instance, by axially shifting the gear 27 until the transmission 16 is interrupted. This result is indeed automatically achieved by means of a switching mechanism not illustrated on figure 4 and that is actuated by the control unit 6. The aforesaid first 15 and the second part 17 of the coupling element 13 are made in this case of the gears of the transmission 16. As also illustrated on figure 4, additional couplings 30 and 31 can also be used in order to get the main drive 1 and the auxiliary drive 2 co-operating respectively with the gears 32 and 33 of the aforesaid transmissions 16 and 18. This way, it becomes possible to use drives 1 and 2 as well as motors having a large speed. Consequently, the moments applied to the motors can be kept limited. The additional transmission 31 between the auxiliary drive 2 and the aforesaid shaft 19 offers the possibility to foresee a second coupling element 34, whereby the auxiliary drive 2 can be completely loosened. This coupling element 34 can be designed for instance in the same way as the coupling element 13 already illustrated on figures 5 and 6. Quite obviously, all aforesaid transmissions 16, 18, 30 and 31 may be made of gears, belts, conical gears or combination of these elements. The shot search coupling 5 and more particularly the coupling element 13 must not necessarily be a clutch coupling and may also be made for instance of a continuously connectable coupling element. All aforesaid embodiments can be foreseen with a locking device prohibiting rotation and mounted on the main shaft 3, whereby this device can be switched-on or switched-off.

Claims: Driving system for weaving looms, comprising at least one drive (1,2), a main shaft (3), an auxiliary shaft (4) and a shot search coupling (5) that can achieve the connection or disconnection between the main shaft (3) and the auxiliary shaft (4), characterised in that the connection can occur for a large number of mutually different positions of the main shaft (3) and of the auxiliary shaft (4); and in that said system further comprises detection means (7,8) for determining the angular difference between the positions of the main shaft (3) and of the auxiliary shaft (4), and a control unit (6) that controls the shot search coupling (5) and at least one drive (1,2) for driving the main and/or auxiliary shafts (3,4) in order to create an automatic connection between the main shaft (3) and the auxiliary shaft (4) in function of a set value for the angular difference. Drive system according to claim 1, characterized by the fact that the shot search coupling (5) is mainly composed of a coupling element (13), the first part (15) of which is connected by means of a first transmission (16) to the main shaft (3) of the weaving loom, and the second part (17) of which is connected by means of a second transmission (18) to the auxiliary shaft (4), whereby the transmission ratios of both transmissions (16, 18) are chosen in such a way that the coupling element (13) has a larger speed than the speeds of the main shaft (3) and of the auxiliary shaft (4). Drive system according to claim 2, characterized by the fact that the second part (17) of the coupling element (13) can be connected with a main drive (1) as well as with an auxiliary drive (2). Drive system according to claim 2, characterized by the fact that the first part (15) of the coupling element (13) is connected with a main drive (1), while the second part (17) of the coupling element (13) is connected with an auxiliary drive (2). Drive system according to one of the previous claims, characterized by the fact that at least the main drive (1), the auxiliary drive (2) and the coupling element (13) are mounted on the same shaft (19). Drive system according to claim 5, characterized by the fact that the main drive (1), the auxiliary drive (2), the coupling element (13) and a brake are forming one single assembly (22).

Inventors: VAN BOGAERT, PHILIPPE, VANDENBROUCKE, ANDRE, Vandenbroucke, André
Applicants: PICANOL N.V.
Application year: 1987
Main classification: D03D51
IPC codes: D03D51