Method for forming a shed on a dobby weaving machine and dobby weaving machine

Abstract

In a method for forming a shed on a dobby weaving machine having a plurality of heald shafts and a plurality of shaft drives, wherein each shaft drive drives at least one of the heald shafts independently of the other heald shafts via at least one transmission mechanism, wherein the at least one transmission mechanism defines a first and a second mechanical reversal point (MP1, MP2) of the at least one heald shaft driven by it, the shaft drive driving the at least one heald shaft is operated with an alternating direction of rotation. The at least one heald shaft is moved towards the first mechanical reversal point (MP1); upon reaching the first mechanical reversal point (MP1) of the heald shaft, the direction of rotation of the shaft drive is maintained, so that a first operational reversal point (BP1) of the heald shaft coincides with the first mechanical reversal point (MP1) of the heald shaft.The at least one heald shaft is moved via a shed closing position (13) in the direction of the second mechanical reversal point (MP2) and at the latest when the second mechanical reversal point (MP2) of the heald shaft is reached, the direction of rotation of the shaft drive is reversed to form a second operational reversal point (BP2) of the heald shaft.

Description

[0001] The present invention relates to a method for forming a shed on a dobby weaving machine having a plurality of heald shafts and a plurality of shaft drives. In this case, each shaft drive drives at least one of the heald shafts independently of the other heald shafts via at least one transmission mechanism. The at least one transmission mechanism defines a first and a second mechanical reversal point of the at least one heald shaft, and the shaft drive driving the at least one heald shaft is operated with alternating rotational directions. Furthermore, the invention relates to a corresponding dobby weaving machine.

[0002] It is known from the prior art not to drive the heald frames of dobby weaving machines with a common shedding drive, but rather to equip the heald frames with individual drives. The motor drives the associated heald frame in a conventional manner via a crank drive and a transmission system of deflection levers. A dobby weaving machine with such individually driven heald frames is shown, for example, in EP 1 260 620 A1.

[0003] In addition to rotating drives, i.e., continuous drives, shaft drives have also become known that operate with alternating directions of rotation or oscillation. The shaft drives change their direction of rotation when the shaft end positions (the high shed position or the low shed position) are reached.

[0004] Such a drive system with alternating directions of rotation is shown in EP 3 327 190 A1. Individual heald shafts are to be held in an open position in accordance with the weaving pattern, while other heald shafts continue to be driven. The heald shafts to be stopped are first moved beyond the high shed position or the low shed position and then stopped so that the heald shaft remains in a specific open position. The heald shafts are then driven from this position in the opposite direction, so that the previously passed high shed or low shed position is traversed again. The direction of movement of the respective drive is reversed for this purpose.

[0005] The object of the present invention is to propose a method for forming a shed on a shaft weaving machine which reduces the load on the shaft drives operated with alternating directions of rotation.

[0006] The problem is solved by a method for forming a shed on a dobby weaving machine and a dobby weaving machine having the features of the independent patent claims.

[0007] A method is proposed for forming a shed on a dobby weaving machine having a plurality of heald shafts and a plurality of shaft drives. Each shaft drive drives at least one of the heald shafts independently of the other heald shafts via at least one transmission mechanism. The at least one transmission mechanism defines a first and a second mechanical reversal point of the at least one heald shaft, and the shaft drive driving the at least one heald shaft is operated in an oscillating manner with alternating rotational directions.

[0008] In the method it is proposed that the at least one heald frame is moved in the direction of the first mechanical reversal point, when the first mechanical reversal point of the heald frame is reached, the direction of rotation of the frame drive is maintained so that a first operational reversal point of the heald frame coincides with the first mechanical reversal point of the heald frame, that the at least one heald frame is moved via a shed closing position in the direction of the second mechanical reversal point and that at the latest when the second mechanical reversal point of the heald frame is reached, the direction of rotation of the frame drive is reversed to form a second operational reversal point of the heald frame.

[0009] Unlike the prior art, the direction of rotation is not reversed upon reaching each of the shaft end positions. Rather, according to the invention, the direction of rotation of the shaft drive is only reversed in one of the two shaft end positions. In the other shaft end position, however, the shaft drive is operated as a through-feed drive. This allows for very gentle operation on the drive. While in fully oscillating operation the shaft drive must be accelerated repeatedly and very strongly, reaching up to twice the speed of a through-feed drive in the shed closing position, the method according to the invention limits the speed of the shaft drive to the speed of a through-feed drive. As with the through-feed drive and fully oscillating operation, a guide shaft can be used to guide the drive.The guide shaft can be formed by an imaginary guide shaft or the drive of the weaving machine's main shaft. Furthermore, by passing through one of the two shaft end positions without reversing the shaft drive's rotation direction, an acceleration and deceleration phase is eliminated, which further reduces the load on the shaft drive. It is not absolutely necessary for the shaft drive's rotation direction to be reversed in each movement cycle, at the latest when the second mechanical reversal point is reached. For example, it is also possible to operate the shaft drive in continuous operation for several revolutions and then to complete another movement cycle with the direction of rotation reversed.

[0010] The process distinguishes between mechanical reversal points and operational reversal points. The mechanical reversal points correspond to the reversal points of the heald frame, which are specified by the transmission mechanism during a fully continuous shaft drive and determine the maximum possible stroke of the heald frame between the high shed position and the low shed position. The operational reversal points, on the other hand, are the reversal points of the heald frame actually reached during operation. The operational reversal point, which is passed through without reversing the direction of rotation of the shaft drive, corresponds to the mechanical reversal point. The operational reversal point at which the direction of rotation of the shaft drive reversals occurs, however, can differ from the mechanical reversal point.

[0011] It is advantageous if, during regular weaving operation, the at least one heald frame is moved again in the direction of the first mechanical reversal point via the shed closing position after reaching the second operational reversal point. Preferably, the steps of claim 1 are then repeated cyclically. The first operational reversal point is thus passed through again, but with the shaft drive rotating in the opposite direction, and the heald frame is moved again in the direction of the second mechanical reversal point via the shed closing position. At the latest upon reaching the second mechanical reversal point, the direction of rotation of the shaft drive is then reversed again to form the second operational reversal point of the heald frame. During regular weaving operation, the shaft drive is therefore operated in a one-sided oscillating manner.The heald shaft cyclically passes through one of the two mechanical reversal points, while the second operational reversal point of the heald shaft is formed by reversing the direction of rotation of the shaft drive.

[0012] It is also advantageous if the first operational reversal point is the high shed position of the heald frame and the second operational reversal point is the low shed position of the heald frame. This is particularly advantageous with a rapier weaving machine, as there are restrictions imposed by the shop sole and the rapier guide. If the shaft drive reverses its direction of rotation before reaching the second mechanical reversal point in the low shed, these geometric conditions can be taken into account. In particular, deflection of warp threads at the shop sole, which would otherwise occur if the low shed is set too low, is avoided.

[0013] It is also advantageous if the shaft drive is operated according to a predetermined speed curve or a predetermined motion profile from which this speed curve results. This allows particularly gentle operation because a suitable speed can be specified for each phase of the movement cycle. By specifying a motion profile, synchronization with the drive of the weaving machine or the guide shaft of the weaving machine can be achieved in a conventional manner at selected points, such as the shed closure, the high shed position and the low shed position. The motion profile can, for example, contain the specification of a target position over time or the target position in relation to the position of the guide shaft.

[0014] It is also advantageous if the shaft drive is not operated synchronously with a guide shaft of the dobby weaving machine while the heald shaft passes through the second operational reversal point, especially the low shed position. This avoids unnecessarily strong braking and acceleration processes, which place a strain on the shaft drive. The shaft drive can be gently decelerated until the heald shaft reaches the second operational reversal point and gently accelerated again after the heald shaft passes through the second operational reversal point.

[0015] It is advantageous if the shaft drive is operated according to a ramp function while the heald shaft passes through the second operational reversal point. The shaft drive thus follows a ramp function. This allows it to be operated with gentle, even acceleration.

[0016] It is also advantageous if the shaft drive is operated at a constant speed while the heald shaft passes through the first operational reversal point, especially the high shed position. This also ensures particularly gentle operation, as strong braking and acceleration processes are avoided.

[0017] Furthermore, it is advantageous if the shaft drive is operated synchronously with a guide shaft of the dobby weaving machine while the heald shaft passes through the first operational reversal point, especially the high shed position. Due to the constant speed, this is particularly simple and gentle. In particular, this allows the synchronization with the guide shaft of the dobby weaving machine required at the shed closure point to be achieved.

[0018] It is advantageous if the shaft drive is operated at a constant speed from the end point of a weft insertion, during which the heald shaft was in a position between the shed closing position and the second operational reversal point, in particular the low shed position, until the start point of the next but one weft insertion, during which the heald shaft, after passing through the first operational reversal point, in particular the high shed position, is again in a position between the shed closing position and the second operational reversal point, in particular the low shed position. This makes it possible to achieve a particularly long phase with a constant speed that is gentle on the drive, despite the oscillating operation of the shaft drive. In this phase, the operating mode is therefore similar to that of a continuous drive, despite the essentially oscillating operation.

[0019] It is also advantageous if the shaft drive is operated according to a ramp function in terms of speed from the start time of a weft insertion, during which the heald shaft is in a position between the shed closing position and the second operational reversal point, in particular the low shed position, to the end time of the same weft insertion, during which the heald shaft, after passing through the second operational reversal point, in particular the low shed position, is again in a position between the shed closing position and the second operational reversal point, in particular the low shed position. As already described, by following a ramp function in this area, the shaft drive can be gently braked or accelerated, since it does not have to run synchronously with a guide shaft of the weaving machine during this phase.

[0020] It is also advantageous if the height of the second operational reversal point, in particular the low shed position, is changed by changing the specified speed curve or the specified movement profile from which this speed curve results in a range before reaching the second operational reversal point, in particular the low shed position. For example, by specifying a lower speed in a certain range or by specifying a corresponding movement profile, the heald frame can only travel a shorter distance, so that the second operational reversal point moves further away from the second mechanical reversal point. Likewise, by specifying a higher speed or a corresponding movement profile, at least in some areas, the heald frame can travel a longer distance, so that the second operational reversal point moves closer to the second mechanical reversal point.This allows electronic compartment adjustment to be realized in the area of ​​the second mechanical reversal point.

[0021] It is particularly advantageous if the specified speed curve or the specified movement profile from which this speed curve results is only changed at or after the start of weft insertion, at which the heald frame is in a position between the shed closing position and the second operational reversal point, especially the deep shed position. This achieves a long phase with constant speed.

[0022] It is also advantageous if the height of the second operational reversal point is adjusted depending on the pattern, particularly if it is adjusted on a pick-by-pick basis. According to the described method, this can advantageously be done electronically in the weaving machine's control unit. This avoids the need for complex adjustments in the area of ​​the shaft drive rocker for each individual heald shaft. Adjusting the shed stroke on a pick-by-pick basis can be particularly advantageous for satin weaves.

[0023] According to an advantageous embodiment of the method, it is possible to change the height of the shed closure, i.e. the position of the shaft at the time of shed closure (shed closure position). This makes it possible, for example, to set an asymmetrical shed. This can also be done particularly advantageously depending on the weaving pattern and, if necessary, also for individual wefts. The shed closure time is an important and strict synchronization criterion between the shaft loom and the heald shafts in weaving technology. If the weaving process speed remains constant, the shed closure times follow a temporally equidistant sequence. For the purpose of changing the height of the shed closure, it is now possible to change the speed of a shaft drive between a first and a second of these shed closure times in such a way that it changes on average (e.g.decreased), while the speed between the second and third shed closing times is changed in such a way that, on average, it changes in the opposite direction (in this example, increased). In this way, the shaft position at the shed closing time, i.e., the height of the shed closing position, is adjusted.

[0024] It is advantageous if the height of the shed closing position is changed by changing the specified speed curve or the specified movement profile from which this speed curve results in a range before and / or after reaching the second operational reversal point, in particular the low shed position.

[0025] It is particularly advantageous if the predetermined speed curve or the predetermined movement profile from which this speed curve results is only changed at or after the start time of the weft insertion, at which the heald frame is in a position between the shed closing position and the second operational reversal point, in particular the low shed position, and / or if the predetermined speed curve is only changed before the end time of the same weft insertion, at which the heald frame is still in a position between the shed closing position and the second operational reversal point, in particular the low shed position. The start time of the weft insertion is predetermined and is not influenced by the altitude of the shed closing position.

[0026] The shed closing position is always defined as the position of the heald frame at the time of shed closing. This can therefore be the unchanged shed closing position that the heald frame assumes when operated according to the specified speed curve or the specified motion profile from which this speed curve results. However, if, as in the aforementioned embodiment, the speed curve or the specified motion profile from which this speed curve results is changed to change the height of the shed closing position, the shed closing position is the changed shed closing position.

[0027] According to another embodiment of the method, it is further advantageous if the height of the shed closing position is changed by changing the specified speed curve or the specified movement profile from which this speed curve results in a range before and / or after reaching the first operational reversal point, in particular the high shed position. For example, a somewhat lower speed or a corresponding movement profile can be specified for the shaft drive in this range. Depending on the specified speed or movement profile, it is possible to simultaneously set or change the height of the second operational reversal point, or to maintain it.

[0028] Preferably, the predetermined speed curve or the predetermined movement profile from which this speed curve results is only changed at or after the end time of the weft insertion, at which the heald frame was in a position between the shed closing position and the second operational reversal point, in particular the deep shed position, and / or preferably the predetermined speed curve or the movement profile from which this speed curve results is changed before the start time of the next but one weft insertion, at which the heald frame is again in a position between the shed closing position and the second operational reversal point, in particular the deep shed position. In this way, the phases of reaching the first and second operational reversal point can each be controlled separately. For example, the change in the speed curve orThe movement profile in the high shed position area affects not only the reaching of the shed closing position, but also the reaching of the second operational reversal point. This can be taken into account by specifying a specific speed or a movement profile in each phase of a movement cycle.

[0029] It is also advantageous if the speed curve or the predetermined movement profile from which this speed curve results is only changed upon or after reaching the shed closing position after the end time of weft insertion, at which the heald frame was in a position between the shed closing position and the second operational reversal point, in particular the deep shed position. It is also advantageous if the predetermined speed curve or the predetermined movement profile from which this speed curve results is changed before or until the next time the shed closing position is reached after the heald frame has passed through the first operational reversal point.

[0030] As long as the time integral over the speed modification between a first and a second compartment closing time and the time integral over the speed modification between the second and the third compartment closing time cancel each other out (ie have the same amount but differ in sign), the compartment stroke remains unchanged.

[0031] Furthermore, it is also advantageous for the height of the shed closing position to be changed depending on the pattern, in particular if it is adjusted on a weft-by-weft basis in order to take into account the special features of the weave type.

[0032] The same advantages can also be achieved with a dobby weaving machine for implementing the method, for which protection is also claimed. The dobby weaving machine has a control unit for controlling or electronically generating a guide shaft of the dobby weaving machine and for controlling the dobby drives, which is designed to operate the dobby drives according to the described method.

[0033] In a particularly preferred embodiment, the control unit for operating the shaft drives allows selection between, on the one hand, the method according to the invention and, on the other hand, operation as a continuous drive and / or operation in fully oscillating operation with a change in the direction of rotation at both operational reversal points. The selection can preferably be made individually for each shaft drive.

[0034] In a particularly preferred manner, the selection is made automatically by the control unit and preferably based on the requirements of the order to be woven, which include, for example, the type of fabric weave, the desired or economically necessary minimum operating speed, properties of the yarn material and optical effects to be achieved and / or based on framework data such as specifications for energy consumption or the ambient temperature.

[0035] Alternatively, the selection can also be made manually by an operator.

[0036] Further advantages of the invention are described in the following exemplary embodiments. They show: Fig. 1 an overview of a dobby weaving machine in a schematic, partially sectioned side view, Fig. 2 a schematic representation of a heald frame with a frame drive and a transmission mechanism in a front view, Fig. 3 a schematic representation of a method for forming a shed according to a first embodiment, Fig. 4 is a schematic representation of a method for forming a shed according to a second embodiment, Fig. 5 is a schematic representation of a method for forming a shed according to a third embodiment, Fig. 6 is a schematic representation of a method for forming a shed according to a fourth embodiment, Fig. 7 is a schematic representation of a method for forming a shed according to a fifth embodiment, Fig. 8 is a schematic representation of a method for forming a shed according to a sixth embodiment, Fig. 9 a schematic representation of a method for forming a shed according to a seventh embodiment, and Fig. 10 is a schematic illustration of a conventional method for forming a shed with a continuous shaft drive.

[0037] In the following description of the exemplary embodiments, features which are identical and / or at least comparable in their design and / or mode of operation in the various figures are each provided with the same reference numerals. Furthermore, features are usually only explained in detail when they are mentioned for the first time, whereas the following exemplary embodiments only address the differences from the exemplary embodiments already described. If features are not explained in detail again, their design and / or mode of operation corresponds to the design and mode of operation of the features already described with reference to one or more of the preceding figures. Furthermore, for reasons of clarity, often only one or only a few of several identical components or features are labeled.

[0038] Fig. 1 shows a dobby weaving machine 1 in a schematic, partially sectioned side view. The dobby weaving machine 1 includes, in a conventional manner, a warp beam 5, from which warp threads 6 are fed to a shed 2 in a warp direction KR. The shed 2 is formed in the present case by heald frames 3, which can be moved back and forth between two reversal points in a likewise known manner. In the heald frames 3, the warp threads 6 are each guided in heddles (not designated here). In the present illustration, only two heald frames 3 are shown. In reality, however, depending on the weaving pattern, considerably more heald frames 3 can be provided. Furthermore, the dobby weaving machine 1 has a reed 7, with which an inserted weft thread (not designated here) can be beaten onto a fabric edge (not designated here), as shown by the dash-dotted representation of the reed 7.The weft insertion means are not shown here and can, in the usual way, include, for example, one or more rapiers, air jets, or projectiles. The finished woven fabric 8 is then drawn off in the warp direction KR and wound onto a fabric beam 9 of the dobby weaving machine 1.

[0039] As mentioned, the heald frames 3 are each movable between two reversal points. This allows the heald frames 3 and thus the warp threads 6 guided by them to be moved alternately from the upper shed 15 to the lower shed 16 and back. According to the present illustration, a first operational reversal point BP1 and a second operational reversal point BP2 are shown. These are the points at which the respective heald frame 3 actually reverses in the respective movement cycle. These can differ from mechanical reversal points MP1, MP2, as will be explained below. Furthermore, a zero position 18 of the shed 2 is shown in a dash-dotted line. This is the position which the warp threads 6 have at the shed closing time FS (see Fig. 3). At this point, the heald shafts 3 are in the shed closing position 13 (see Fig. 3).

[0040] The dobby weaving machine 1 further comprises a drive 11 for driving the reed shaft 10 or the reed 7. Likewise, shaft drives 4 are provided for driving the heald shafts 3. As a rule, one shaft drive 4 drives one heald shaft 3, as will be explained below with reference to the Fig. 2 will be explained later. However, it is also conceivable for one shaft drive 4 to drive multiple heald shafts 3. The heald shaft(s) 3 driven by one shaft drive 4 can be moved independently of heald shafts 3 driven by other shaft drives 4. The shaft drives 4 are operated at least pointwise synchronously with a guide shaft of the heald weaving machine 1. The heald weaving machine further comprises a control unit 17, which controls the shaft drives 4 and, according to the present illustration, also the drive 11 of the reed shaft 10.

[0041] Fig. 2 shows a schematic front view of a heald frame 3 with an associated frame drive 4 and a transmission mechanism 12, via which the frame drive 4 drives the heald frame 3. The transmission mechanism 12 includes, in a conventional manner, an articulated gear, which in this case has a crank 21, a coupling rod 22, and deflection levers 19, which raise and lower the heald frame 3 via lifting rods 23. Furthermore, the transmission mechanism 12 includes a beam 20 for connecting the two deflection levers 19. The frame drive 4 can be operated with alternating directions of rotation DR or in continuous operation in order to move the heald frame 3 back and forth or up and down between two reversal points.

[0042] The transmission mechanism 12 specifies a first and a second mechanical reversal point MP1, MP2. The first and second mechanical reversal points MP1, MP2 define a maximum possible stroke H maxof the heald frame 3. In the present example, the first mechanical reversal point MP1 designates the highest possible position of the heald frame 3 and the second mechanical reversal point MP2 designates the lowest possible position. The operational reversal points BP1 and BP2 must be distinguished from the mechanical reversal points MP1, MP2. These are the points to which the respective heald frame 3 actually reverses in one movement cycle. These points BP1, BP2 are determined by the operating mode of the frame drive 4 and can differ from the mechanical reversal points MP2, MP2 or coincide with them. Furthermore, 13 designates the shed closing position, which is located between the operational reversal points BP1 and BP2 and is usually arranged centrally between them. In the present example, the first operational reversal point BP1 corresponds to the high shed position and the second operational reversal point BP2 corresponds to the low shed position.However, depending on the type and mode of operation of the dobby weaving machine 1, this could also be the other way around.

[0043] According to the method, the heald frame 3 is now moved in the direction of the first mechanical reversal point MP1, in the present example upwards towards the high shed position. Upon reaching the high shed position, the frame drive 4 maintains its direction of rotation DR, so that the heald frame 3 passes through the first mechanical reversal point MP1 in the direction of the low shed position. In this case, the first operational reversal point BP1 of the heald frame 3 coincides with the first mechanical reversal point MP1 of the heald frame 3. Subsequently, with the direction of rotation of the frame drive 4 still in the same, the heald frame 3 is moved downwards via the shed closing position 13 towards the second mechanical reversal point MP2, in this example downwards towards the low shed position.At the latest when the second mechanical reversal point MP2 is reached, the direction of rotation DR of the shaft drive 4 is reversed in order to form the second operational reversal point BP2 of the heald shaft 3. It is conceivable that the second operational reversal point BP2 also coincides with the second mechanical reversal point MP2, namely when the direction of rotation DR of the shaft drive 4 is only reversed when the second mechanical reversal point MP2 is reached. However, it is also possible to reverse the direction of rotation DR before the second mechanical reversal point MP2 is reached. This is shown in the present example. In this case, the second operational reversal point BP2 is higher than the second mechanical reversal point MP2, so that the actual stroke H of the heald shaft 3 is also smaller than the maximum possible stroke H. maxAs already mentioned, it would also be conceivable to pass through the lower mechanical reversal point so that the lower mechanical reversal point coincides with the lower operational reversal point. In this case, to form the upper operational reversal point, the direction of rotation would be reversed before or at the latest upon reaching the upper mechanical reversal point. In this case, the upper operational reversal point would be the second operational reversal point BP2, and the upper mechanical reversal point would be the second mechanical reversal point MP2. The described one-sided oscillating process enables particularly drive-friendly and flexible operation of the dobby weaving machine 1.

[0044] To further explain the method according to the invention, reference will now first be made to Fig. 10. This shows a speed-time diagram in the upper section and a corresponding stroke-time diagram in the lower section for a conventional, continuous shaft drive 4 (see Fig. 1 and Fig. 2). On the time axis, cyclically recurring points in time that are important for the weaving process are plotted, as well as at least some of the corresponding angles. SS denotes the start time of a weft insertion, ES the end time of a weft insertion, and FS the shed closure time. The shed closure time also corresponds to an angle of 360° of the guide shaft of the dobby weaving machine 1. Furthermore, the angles of the guide shaft of 180° are also plotted. At 180° of the guide shaft, the angle generated by the dobby drive 4 (see Fig. 1 and Fig. 2) Driven heald shaft 3 is either in the high shed position or in the low shed position. The vertical axis in the speed-time diagram shows the speed n of the shaft drive 4. The vertical axis in the stroke-time diagram also shows the progression of the stroke H of the heald shaft 3 over time.

[0045] As the speed-time diagram in the upper part of the Fig. 10, the shaft drive 4 is operated at a constant speed n and thus in rotation. In this case, both the first mechanical reversal point MP1 and the second mechanical reversal point MP2 are always passed through without reversing the direction of rotation of the shaft drive 4. In other words, the first operational reversal point BP1 coincides with the first mechanical reversal point MP1, and the second operational reversal point BP2 coincides with the second mechanical reversal point MP2. The actual stroke H of the heald shaft 3 (see Fig. 2) corresponds to the maximum possible stroke H max and is in the stroke-time diagram in the lower part of the Fig. 3 is shown in a solid line. With an oscillating shaft drive 4, a similar stroke curve would result, however, due to the constant reversal of rotation direction with acceleration and deceleration, it would deviate from the sinusoidal curve. For the following explanation of the inventive unidirectional oscillating method based on the Fig. 3 - 9 should therefore be the Fig. 10 shows the curve of the stroke H over time t with the shaft drive 4 running continuously (see Fig. 2), where the actual stroke H exceeds the maximum stroke H max reached, serve as a reference and is shown there in dashed lines.

[0046] Fig. 3 now shows a first embodiment of the method for forming a shed 2 using a loom 2 in the upper area of ​​the Fig. 3 and a stroke-time diagram shown below. The dashed lines show the stroke H over time when, as shown in the Fig. 10, with a continuous shaft drive 4 (see Fig. 2) the actual stroke H the maximum stroke H max As in Fig. 3, the shaft drive 4 is operated according to a speed ramp function during a weft insertion 24, during which the heald shaft 3 is located in the area of ​​the second operational reversal point BP2. In Fig. In the example shown in Figure 3, this would be while the heald frame 3 is located in the area of ​​the low shed 16. This can be achieved by specifying the speed of the frame drive 4 directly or by a motion profile from which the corresponding speed is derived. In this area, the heald frame 3 is operated in a non-synchronized manner with respect to the guide shaft of the dobby weaving machine 1. This allows the frame drive 4 to move with uniform acceleration and thus in a drive-friendly manner in the area of ​​the second operational reversal point BP2.

[0047] From the end time ES of this weft insertion 24 until the start time SS of the next but one weft insertion 24, during which the heald frame 3 is again in the area of ​​the low shed 16, the shaft drive 4 is operated at a constant speed and synchronously with the guide shaft of the dobby weaving machine 1. Even during the weft insertion 24, which in turn follows the next but one weft insertion 24, as well as during the passage of the heald frame 3 through the first operational reversal point BP1, the shaft drive 4 is operated at a constant speed and synchronously with the guide shaft of the dobby weaving machine 1. In this area, the shaft drive 4 is thus operated in a drive-friendly manner like a through-feed drive. In contrast to the purely oscillating operation of the prior art, the direction of rotation of the shaft drive 4 is only reversed with every second shed change of the heald frame 3.In this way, high speeds and excessive accelerations of the shaft drive 4 can be avoided, whereby the load on the shaft drive 4 can also be reduced by eliminating one of the two braking and acceleration phases.

[0048] In the example shown here, the direction of rotation DR of the shaft drive 4 is reversed before reaching the second mechanical reversal point MP2. Therefore, the second operational reversal point BP2 lies before the second mechanical reversal point MP2. The stroke H of the heald shaft is therefore smaller than the maximum stroke H in this case. max

[0049] Fig. Figure 4 shows an embodiment of the method in which the second operational reversal point BP2 is located even further before the second mechanical reversal point MP2. The stroke H is thus smaller than the maximum stroke H max and also smaller than the stroke according to Fig. 3, as can be seen from the stroke-time diagram shown below. For reference, the course of the stroke H over time is shown in dashed lines when, as shown in the Fig. 10, with a continuous shaft drive 4 (see Fig. 2) the actual stroke H the maximum stroke H max Furthermore, for comparison, the course of the stroke H over time is shown in dotted lines according to Fig. 3. The adjustment of the stroke H is carried out by changing the height of the second operational reversal point BP2. This is done according to the procedure of Fig. 4 is achieved by specifying a specific speed curve or a corresponding movement profile, from which the speed results, to the shaft drive 4 in the area before reaching the second operational reversal point BP2. The shaft drive 4 is thus driven at least in the area before reaching the second operational reversal point BP2 with a speed which is different from the speed specified in Fig. 3 shown ramp function, as can be seen from the Fig. 4 speed-time diagram shown above. The ramp function of the Fig. 3 is still shown in dashed lines.

[0050] In order to change or adjust the stroke H of the heald frame 3 in this way, the frame drive 4 is assigned a slightly lower speed n1.1 or a corresponding movement profile than in the case of the weft insertion 24 starting from the starting time SS of the weft insertion 24, in which the heald frame 3 is located in the area of ​​the deep shed 16. Fig. 3. The heald frame 3 can therefore only cover a slightly shorter distance between the starting time SS of the weft insertion 24 and the moment the frame is stopped, so that the second operational reversal point BP2, which in the present case corresponds to the low shed position, is Fig. 3 slides even further upward. This allows a stroke adjustment in the lower shed 16 to be achieved. In order to return from this second operational reversal point BP2, which has been moved upwards, the rotational speed n1.2 is correspondingly lower until the end time ES of the weft insertion 24, or a corresponding movement profile is selected.

[0051] Fig. Figure 5 shows an embodiment of the method in which the second operational reversal point BP2 approaches the second mechanical reversal point MP2 more closely than in Fig. 3. For reference, the course of the stroke H over time is shown in dashed lines according to the Fig. 10 and in dotted lines the course of the stroke H over time according to Fig. 3. From the starting time SS of a weft insertion 24, in which the heald shaft 3 is located in the area of ​​the deep shed 16, the shaft drive 4 is given a somewhat higher speed n2.1 than in the process embodiment according to Fig. 3 or a corresponding movement profile is specified, as can be seen from the speed-time diagram in the upper part of the Fig. 5. In the stroke-time diagram in the lower part of the Fig. 5 is again the stroke H according to Fig. 3 enlarged stroke H clearly visible. To Fig. 3 to return to the second operational reversal point BP2 which has slipped downwards, the speed n2.2 is correspondingly higher or a corresponding movement profile is selected.

[0052] Fig. Figure 6 shows a further embodiment of the method in which the height of the shed closing position 13 was changed compared to the original position of the shed closing position 13. In the lower stroke-time diagram, the original height of the shed closing position 13 is shown in a dashed line and the height of the shed closing position 13 after adjustment is shown in a solid line. As can be seen, the shed closing position 13 is shifted in the direction of the first mechanical reversal point MP1, in this case in the direction of the high shed position. The stroke H, however, is compared to Fig. 3 remained the same and thus also smaller than the maximum stroke H max , which is activated when the shaft drive 4 (see Fig. 2) according to the Fig. 10 is reached. Accordingly, the second operational reversal point BP2 is also located before the second mechanical reversal point MP2. The dashed lines again show the course of the stroke H over time with a continuous shaft drive 4 (see Fig. 2). The course of the stroke H over time is also shown according to the Fig. 3 shown here in dotted lines.

[0053] This shift of the shed closing position in the direction of the first mechanical reversal point MP1 with a constant stroke can be achieved by, on the one hand, specifying a speed curve or a corresponding movement profile to the shaft drive 4 at least in an area before and / or after reaching the first operational reversal point BP1 such that the speed n3.3, n3.4 there is below the Fig. 3. On the other hand, from the start time SS of a weft insertion 24, in which the heald shaft 3 is located in the area of ​​the deep shed 16, until the end ES of this weft insertion 24, the shaft drive 4 is assigned a Fig. 3 slightly higher speed n3.1, n3.2 specified.

[0054] Fig. Figure 7 shows a further embodiment of the method, in which the height of the compartment closing position 13 was also changed, in this case also shifted upwards towards the high compartment position. The stroke H remains the same as the stroke H according to Fig. 3 (shown in dash-dotted form) is the same as in Fig. 7 below. The dashed lines show the course of the stroke H over time with a continuous shaft drive 4 (see Fig. 2) is shown.

[0055] The height of the shed closing position 13 is changed in the present example in that the shaft drive 4 after the end time ES of the weft insertion 24, in which the heald shaft is in the area of ​​the low shed 16, until before the start time SS of the next but one weft insertion 24, in which the heald shaft 3 is again in the area of ​​the low shed 16, is assigned a Fig. 3, a slightly lower speed n4.3 or a corresponding movement profile is specified. The upper shed 15 is thereby traversed somewhat more slowly by the heald frame 3. In addition, the frame drive 4 is specified a slightly higher speed (n4.1, n4.2) from the start time SS to the end time ES of the weft insertion 24, at which the heald frame 3 is in the area of ​​the lower shed 16, so that the second operational reversal point BP2 is at the same position as in Fig. 3. The stroke H is thus compared to the execution of the Fig. 3 not reduced.

[0056] The Fig. 3 deviating speed n4.3 is preferably specified only from the shed closing time FS following a weft insertion 24, during which the heald shaft 3 was in the area of ​​the low shed 16, and only until the shed closing time FS before the next but one weft insertion 24, during which the heald shaft 3 is again in the area of ​​the low shed.

[0057] As still in Fig. 8, it is also possible to carry out a stroke adjustment in addition to changing the height of the compartment closing position 13 by Fig. 3 the high compartment 15 is passed through more slowly according to the speed n5.1 shown here and in contrast to Fig. 6 and Fig. 7, no compensation is made by a higher speed in other areas. Therefore, both the height of the compartment closing position 13 and the second operational reversal point BP2 shift upwards.

[0058] The Fig. 3 deviating speed n5.1 is preferably specified only in the range between the compartment closing times FS, which include the first operational reversal point BP1.

[0059] As in Fig. As shown in Figure 9, it is of course also possible to adjust the height of the compartment closing position 13 not only upwards, but also downwards. Fig. In the stroke-time diagram shown below in Figure 9, the original position of the compartment closing position 13 is shown in dashed lines and the new position of the compartment closing position 13 is shown in solid lines.

[0060] As in Fig. 9 above, this is achieved by providing the shaft drive 4 with a speed which is higher than the speed of the weft insertion 24, after the end time ES of a weft insertion 24, in which the heald shaft 3 is in the area of ​​the low shed 16, until the start time SS of the next but one weft insertion 24, in which the heald shaft 3 is again in the area of ​​the low shed. Fig. 3 slightly higher speed n6.3 or a corresponding motion profile is specified. Preferably, the shaft drive 4 is also assigned the Fig. 3 Deviating speed n6.3 is only specified in the range between the two compartment closing times FS, which surround the first operational reversal point BP1. Furthermore, the shaft drive 4 is assigned a speed from the start time SS to the end time ES of the weft insertion 24, in which the heald shaft 3 is located in the area of ​​the deep shed 16, compared to Fig. 3 slightly lower speed (n6.1, n6.2) or a corresponding motion profile is specified. Thus, the stroke H corresponds to that in Fig. 3, like the one in the lower part of the Fig. The curve of the stroke H over time can be seen in Figure 9.

[0061] The present invention is not limited to the illustrated and described embodiments. Modifications within the scope of the claims are also possible. List of reference symbols 1 dobby weaving machine 2 sheds 3 Heald shaft 4 shaft drive 5 Warp beam 6 warp threads 7 reed 8 goods 9 Ware tree 10 blade shaft 11 Blade shaft drive 12 Transmission mechanism 13 Compartment closing position 14 Speed ​​curve 15 high compartments 16 deep compartment 17 Control unit 18 Zero position 19 bell crank 20 beams 21 Crank 22 coupling rod 23 Lifting rod 24 shot entry n speed n1.1 Speed n1.2 speed n2.1 Speed n2.2 speed n3.1 Speed n3.2 Speed n3.3 Speed n3.4 Speed n4.1 Speed n4.2 Speed n4.3 Speed n5.1 Speed n6.1 Speed n6.2 Speed n6.3 Speed t time W angle H Hub H max maximum stroke KR warp direction DR direction of rotation MP1 first mechanical reversal point MP2 second mechanical reversal point BP1 first operational turning point BP2 second operational turning point ES End time shot entry SS start time shot entry FS subject completion date

Claims

[1] Method for forming a shed (2) on a shaft weaving machine (1) which has a plurality of heald shafts (3) and a plurality of shaft drives (4), wherein each shaft drive (4) drives at least one of the heald shafts (3) independently of the other heald shafts (3) via at least one transmission mechanism (12), wherein the at least one transmission mechanism (12) defines a first and a second mechanical reversal point (MP1, MP2) of the at least one heald shaft (3) driven by it, and wherein the shaft drive (4) driving the at least one heald shaft (3) is operated with an alternating direction of rotation (DR), characterized by , that the at least one heald shaft (3) is moved in the direction of the first mechanical reversal point (MP1), when the first mechanical reversal point (MP1) of the heald shaft (3) is reached, the direction of rotation (DR) of the shaft drive (4) is maintained so that a first operational reversal point (BP1) of the heald shaft (3) coincides with the first mechanical reversal point (MP1) of the heald shaft (3), that the at least one heald shaft (3) is moved over a shed closing position (13) in the direction of the second mechanical reversal point (MP2) and that at the latest when the second mechanical reversal point (MP2) of the heald shaft (3) is reached, the direction of rotation (DR) of the shaft drive (4) is reversed to form a second operational reversal point (BP2) of the heald shaft (3). [2] Method according to claim 1, characterized bythat in regular weaving operation, the at least one heald shaft (3) is moved again in the direction of the first mechanical reversal point (MP1) after reaching the second operational reversal point (BP2) via the shed closing position (13), wherein the steps of claim 1 are preferably repeated cyclically. [3] Method according to claim 1 or 2, characterized by that the first operational reversal point (BP1) is the high shed position of the weaving shaft (3) and the second operational reversal point (BP2) is the low shed position of the weaving shaft (3). [4] Method according to one of claims 1-3, characterized by that the shaft drive (4) is operated according to a predetermined speed curve or a predetermined movement profile from which this speed curve results. [5] Method according to one of claims 1-4, characterized bythat the shaft drive (4) is not operated synchronously with respect to a guide shaft of the shaft weaving machine (1) during the passage of the second operational reversal point (BP2) by the heald shaft (3). [6] Method according to one of claims 4 or 5, characterized by that the shaft drive (4) is operated in terms of speed according to a ramp function while the heald shaft (3) passes through the second operational reversal point (BP2). [7] Method according to one of claims 4-6, characterized by that the shaft drive (4) is operated at a constant speed (n) while the heald shaft (3) passes through the first operational reversal point (BP1). [8] Method according to one of claims 4-7, characterized by that the shaft drive (4) is operated synchronously with the guide shaft of the shaft weaving machine (1) while the heald shaft (3) passes through the first operational reversal point (BP1). [9] Method according to claim 7, characterized by that the shaft drive (4) is operated at a constant speed (n) from an end time (ES) of a weft insertion (24), at which the heald shaft (3) was in a position between the shed closing position (13) and the second operational reversal point (BP2), to a start time (SS) of a next but one weft insertion (24), at which the heald shaft (3) is again in a position between the shed closing position (13) and the second operational reversal point (BP2) after passing through the first operational reversal point (BP1). [10] Method according to claim 6, characterized byin that the shaft drive (4) is operated from a start time (SS) of a weft insertion (24), at which the heald shaft (3) is in a position between the shed closing position (13) and the second operational reversal point (BP2), to the end time (ES) of the same weft insertion (24), at which the heald shaft (3) is again in a position between the shed closing position (13) and the second operational reversal point (BP2) after passing through the second operational reversal point (BP2), in terms of speed according to a ramp function. [11] Method according to one of claims 4-10, characterized bythat a height of the second operational reversal point (BP2) is changed by changing the predetermined speed curve or the predetermined movement profile from which this speed curve results in a range before reaching the second operational reversal point (BP2), wherein preferably the predetermined speed curve or the movement profile from which this speed curve results is only changed at or after the start time (SS) of the weft insertion (24), at which the heald frame (3) is in a position between the shed closing position (13) and the second operational reversal point (BP2). [12] Method according to one of claims 4-11, characterized bythat a height of the shed closing position (13) is changed by changing the predetermined speed curve or the movement profile from which this speed curve results in a range before and / or after reaching the second operational reversal point (BP2), wherein preferably the predetermined speed curve or the movement profile from which this speed curve results is only changed at or after the start time (SS) of the weft insertion (24), at which the heald frame (3) is in a position between the shed closing position (13) and the second operational reversal point (BP2), and / or wherein preferably the predetermined speed curve or the movement profile from which this speed curve results is only changed before the end time (ES) of the same weft insertion (24), at which the heald frame (3) is still in a position between the shed closing position (13) and the second operational reversal point (BP2). [13] Method according to one of claims 4-12, characterized bythat a height of the shed closing position (13) is changed by changing the predetermined speed curve or the predetermined movement profile from which this speed curve results in a range before and / or after reaching the first operational reversal point (BP1), wherein preferably the predetermined speed curve or the predetermined movement profile from which this speed curve results is only changed at or after the end time (ES) of the weft insertion (24), at which the heald frame (3) was in a position between the shed closing position (13) and the second operational reversal point (BP2), and / or wherein preferably the predetermined speed curve or the movement profile from which this speed curve results is before the start time (SS) of the next but one weft insertion (24),in which the heald shaft (3) is again in a position between the shed closing position (13) and the second operational reversal point (BP2), [14] Method according to claim 13, characterized by that the speed curve or the predetermined movement profile from which this speed curve results is only changed when or after reaching the shed closing position (13) after the end time (ES) of the weft insertion (24), at which the heald frame (3) was in a position between the shed closing position (13) and the second operational reversal point (BP2), and / or that the predetermined speed curve or the predetermined movement profile from which this speed curve results is changed before or until the next time the shed closing position (13) is reached after the heald frame (3) has passed through the first operational reversal point (BP1). [15] Method according to one of claims 11-14, characterized bythat the height of the second operational reversal point (BP2) and / or the shed closing position (13) is changed depending on the pattern, in particular is adjusted on a single shot basis. [16] A shaft loom (1) for carrying out the method according to one of the preceding claims, comprising a plurality of heald shafts (3) and a plurality of shaft drives (4), wherein each shaft drive (4) drives at least one of the heald shafts (3) independently of the other heald shafts (3) via at least one transmission mechanism (12), wherein the at least one transmission mechanism (12) defines a first and a second mechanical reversal point (MP1, MP2) of the at least one heald shaft (3) driven by it, and wherein the shaft drive (4) is operable with an alternating direction of rotation (DR), and comprising a control unit (17) for controlling or electronically generating a guide shaft of the shaft loom (1) and for controlling the shaft drives (4), characterized by that the control unit (17) is designed to operate the shaft drives (4) according to one of the preceding claims. [17] Shaft weaving machine (1) according to claim 16, characterized by that the control unit (17) is designed to operate the shaft drives (4) selectively in a first operating mode according to the method according to one of claims 1-15 or in at least one further operating mode in continuous operation and / or in fully oscillating operation. [18] Shaft weaving machine (1) according to the preceding claim, characterized by that the operating mode of the shaft weaving machine (1) can be selected manually. [19] Shaft weaving machine (1) according to claim 17, characterized by that the operating mode of the shaft weaving machine (1) can be selected automatically depending on application data.

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