Method for forming a shed on a dobby loom and dobby loom

Abstract

The invention relates to a method for forming a shed on a dobby loom that has a plurality of heald shafts and a plurality of shaft drives, wherein in each case one 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, and the shaft drive driving the at least one heald shaft is operated with alternating directions of rotation. The at least one heald shaft is moved in the direction of the first mechanical reversal point (MP1). When the first mechanical reversal point (MP1) of the heald shaft is reached, the direction of rotation of the shaft drive is maintained such 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 in the direction of the second mechanical reversal point (MP2) via a shed closure position (13) 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 in order to form a second operational reversal point (BP2) of the heald shaft.

Description

[0001] Method for forming a shed on a shaft loom and shaft loom

[0002] The present invention relates to a method for forming a shed on a dobby loom, which has a plurality of heddles and a plurality of heddle drives. In this method, each heddle drive, via at least one transmission mechanism, drives at least one of the heddles independently of the other heddles, wherein the at least one transmission mechanism defines a first and a second mechanical reversal point of the at least one heddle, and wherein the heddle drive driving the at least one heddle is operated with alternating directions of rotation. The invention further relates to a corresponding dobby loom.

[0003] It is known from the prior art to drive the heddles of dobby looms not with a common shed drive, but rather to equip the heddles with individual drives. The motor drives its assigned heddle in a manner known per se via a crank mechanism and a transmission system of deflection levers. A dobby loom with such individually driven heddles is shown, for example, in EP 1 260 620 A1.

[0004] In addition to rotary drives, i.e., continuous drives, shaft drives have also become known, which are operated with alternating directions of rotation or in an oscillating manner. These shaft drives change their direction of rotation when they reach the end positions of the shaft (the up-folding position or the down-folding position).

[0005] Such a drive system with alternating directions of rotation is shown in EP 3 327 190 A1. In this system, individual shafts are held in an open position in accordance with the weaving pattern, while other shafts continue to be driven. To achieve this, the shafts to be stopped are first moved beyond the up-heel or down-heel position and then stopped, so that the shaft remains in a specific open position. The shafts are then driven from this position in the opposite direction, so that the previously traversed up-heel or down-heel position is passed through again. The direction of movement of the respective drive is reversed for this process.

[0006] The object of the present invention is to propose a method for forming a shed on a shaft loom which reduces the load on the shaft drives operated with alternating directions of rotation.

[0007] The problem is solved by a method for forming a shed on a shaft loom and a shaft loom with the features of the independent patent claims.

[0008] A method for forming a shed on a dobby loom is proposed, which has a plurality of heddles and a plurality of heddle drives. In this method, each heddle drive, via at least one transmission mechanism, drives at least one of the heddles independently of the other heddles. The at least one transmission mechanism defines a first and a second mechanical reversal point for the at least one heddle, and the heddle drive driving the at least one heddle is operated in an oscillating manner with alternating directions of rotation.

[0009] The method proposes that the at least one weaving shaft is moved towards the first mechanical reversal point; upon reaching the first mechanical reversal point of the weaving shaft, the direction of rotation of the shaft drive is maintained, so that a first operational reversal point of the weaving shaft coincides with the first mechanical reversal point of the weaving shaft; that the at least one weaving shaft is moved via a shed-closing position towards the second mechanical reversal point; and that, at the latest upon reaching the second mechanical reversal point of the weaving shaft, the direction of rotation of the shaft drive is reversed to form a second operational reversal point of the weaving shaft. Unlike in the prior art, the direction of rotation is thus not reversed upon reaching each of the shaft end positions. Rather, according to the invention, a reversal of the direction of rotation of the shaft drive only occurs in one of the two shaft end positions.In the opposite shaft end position, the shaft drive operates as a continuous drive. This allows for very gentle operation of the drive. Whereas in fully oscillating operation the shaft drive must be repeatedly accelerated very strongly and, in the closed shed position, reaches up to twice the speed of a continuous drive, the inventive method limits the speed of the shaft drive to that of a continuous drive. As with continuous drives and fully oscillating operation, a guide shaft can be used for drive guidance. This guide shaft can be formed by an imaginary guide shaft or by the drive of the main shaft of the weaving machine.Furthermore, by passing through one of the two shaft end positions without reversing the direction of rotation of the shaft drive, an acceleration and deceleration phase is eliminated, thus further reducing the load on the shaft drive. It is not absolutely necessary for the direction of rotation of the shaft drive to be reversed in every movement cycle at the latest upon reaching the second mechanical reversal point. For example, it is also possible to operate the shaft drive in continuous mode for several revolutions and then perform another movement cycle with a reversal of the direction of rotation.

[0010] The procedure distinguishes between mechanical reversal points and operational reversal points. Mechanical reversal points correspond to the reversal points of the weaving shaft, which are predetermined by the transmission mechanism during a fully continuous shaft drive and determine the maximum possible stroke of the weaving shaft between the up-fold and down-fold positions. Operational reversal points, on the other hand, are the reversal points of the weaving shaft actually reached during operation. The operational reversal point, which is traversed without a reversal of the shaft drive's direction of rotation, corresponds to the mechanical reversal point. The operational reversal point at which the shaft drive's direction of rotation reverses, however, may differ from the mechanical reversal point.

[0011] It is advantageous if, during regular weaving operation, at least one weaving shaft is moved again towards 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 direction of rotation of the shaft drive reversed, and the weaving shaft is moved again towards 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 weaving shaft. In regular weaving operation, the shaft drive is therefore operated in a unidirectional oscillating manner.The weaving shaft cyclically passes through one of the two mechanical reversal points, while the second operational reversal point of the weaving 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-fold position of the heddle and the second operational reversal point is the low-fold position of the heddle. This is particularly beneficial for rapier looms, as there are limitations imposed by the heddle base and the rapier guide. If the heddle drive reverses its direction of rotation before reaching the second mechanical reversal point in the low-fold position, these geometric constraints can be accommodated. In particular, this prevents warp threads from being deflected at the heddle base, which would otherwise occur if the low-fold position is set too low.

[0013] It is also advantageous if the shaft drive is operated according to a predetermined pattern.

[0014] speed curve or a predefined movement profile from which this

[0015] The speed curve results in operation. This allows for particularly gentle operation, as a suitable speed can be specified for each phase of the motion cycle. Furthermore, by specifying a motion profile, synchronization with the drive of the weaving machine or the guide shaft of the weaving machine can be achieved at selected points, such as the shed closure, the up-shed position, and the down-shed position, in a manner known per se. The motion profile can, for example, include the specification of a target position over time or the target position relative to the position of the guide shaft.

[0016] It is also advantageous if the shaft drive is not operated synchronously with a guide shaft of the shaft loom while the weaving shaft passes through the second operational reversal point, particularly the low-space position. This avoids unnecessarily strong braking and acceleration processes that put stress on the shaft drive. The shaft drive can be gently braked until the second operational reversal point of the weaving shaft is reached and gently accelerated again after the second operational reversal point has been reached.

[0017] It is advantageous if the shaft drive is operated according to a ramp function during the passage of the second operational reversal point through the weaving shaft. The shaft drive thus follows a ramp function, allowing for gentle and consistent acceleration.

[0018] It is also advantageous if the shaft drive is operated at a constant speed while passing through the first operational reversal point of the weaving shaft, particularly the high-space position. This again results in particularly gentle operation, as strong braking and acceleration phases are avoided.

[0019] Furthermore, it is advantageous if the shaft drive is operated synchronously with a guide shaft of the shaft loom while passing through the first operational reversal point, particularly the upright position. Due to the constant rotational speed, this is possible in a particularly simple and gentle manner. In particular, this ensures the synchronization with the guide shaft of the shaft loom required at the point of shed closure.

[0020] It is advantageous if the shaft drive operates at a constant speed from the end of a weaving cycle, when the weaving shaft is in a position between the closed shed position and the second operational reversal point, particularly the low shed position, until the start of the next but one weaving cycle, when the weaving shaft, after passing through the first operational reversal point, particularly the high shed position, is again in a position between the closed shed position and the second operational reversal point, particularly the low shed position. This allows for a particularly long phase of constant, drive-friendly speed despite the oscillating operation of the shaft drive. During this phase, the operation, despite its inherent oscillation, resembles that of a continuous drive.

[0021] It is also advantageous if the shaft drive is operated according to a ramp function from the start of a weft entry, when the weft shaft is in a position between the shed closing position and the second operational reversal point, particularly the low shed position, until the end of the same weft entry, when the weft shaft, after passing through the second operational reversal point, particularly the low shed position, is again in a position between the shed closing position and the second operational reversal point, particularly the low shed position. As already described, because the shaft drive follows a ramp function in this area, it can be gently decelerated or accelerated, since it does not have to run synchronously with a guide shaft of the weaving machine during this phase.It is also advantageous to change the elevation of the second operational reversal point, particularly the low-space position, by modifying the specified speed curve or the motion profile from which this speed curve is derived in a region before reaching the second operational reversal point, particularly the low-space position. For example, by specifying a lower speed in a certain region or by specifying a corresponding motion profile, the weaving shaft can travel a shorter distance, thus moving the second operational reversal point further away from the second mechanical reversal point. Likewise, by specifying a higher speed or a corresponding motion profile, at least in certain regions, the weaving shaft can travel a longer distance, thereby moving the second operational reversal point closer to the second mechanical reversal point.This allows for electronic compartment adjustment in the area of ​​the second mechanical reversal point.

[0022] It is particularly advantageous if the predetermined speed curve or the predetermined motion profile from which this speed curve is derived is only changed at or after the start of the weft insertion, at which point the weft shaft is in a position between the shed closing position and the second operational reversal point, in particular the deep shed position. This results in a long phase with constant speed.

[0023] It is also advantageous if the height of the second operational reversal point is changed depending on the pattern, in particular if it is adjusted individually. According to the described method, this can advantageously be done electronically in the control unit of the weaving machine. This avoids the need for time-consuming adjustments in the area of ​​the heddle drive arm for each individual heddle. Adjusting the shed stroke individually can be particularly advantageous for satin weaves. 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 heddle at the time of closure (shed closure position). This makes it possible, for example, to set an asymmetrical shed. This, too, can be done particularly advantageously depending on the weaving pattern and, if necessary, individually.The shed closure point is a crucial and strictly defined synchronization criterion between the dobby loom and the weaving heddle. At a constant weaving speed, the shed closure points occur in equidistant sequences. To alter the height of the shed closure, the heddle speed can be adjusted between the first and second of these closure points so that the average speed changes (e.g., decreases), while between the second and third closure points, the speed is adjusted so that the average speed changes in the opposite direction (in this example, increases). In this way, the heddle position at the shed closure point, and thus the height of the shed closure position, is changed.

[0024] Advantages arise when the height of the compartment closing position is changed by modifying the specified speed curve or the specified movement profile from which this speed curve results in an area before and / or after reaching the second operational reversal point, in particular the low compartment position.

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

[0026] The sheave closing position is always defined as the position of the weaving shaft at the time of sheave closing. This can therefore be the unchanged sheave closing position that the weaving shaft assumes when operated according to the specified speed curve or the specified motion profile from which this speed curve is derived. However, if, as in the aforementioned design, the speed curve or the specified motion profile from which this speed curve is derived is changed to alter the height of the sheave closing position, then the sheave closing position is the altered sheave closing position.

[0027] According to another embodiment of the method, it is further advantageous to change the height of the compartment closing position by modifying the predefined speed curve or the predefined motion profile from which this speed curve is derived, in a range before and / or after reaching the first operational reversal point, particularly the upright compartment position. For example, a slightly lower speed or a corresponding motion profile can be specified for the shaft drive in this range. Depending on the specified speed or motion profile, it is also possible to simultaneously adjust or change the height of the second operational reversal point, or to maintain it as is.

[0028] Preferably, the predetermined speed curve or the predetermined motion profile from which this speed curve is derived is changed only at or after the end time of the shot entry, at which the weft shaft 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 motion profile from which this speed curve is derived is changed before the start time of the next but one shot entry, at which the weft shaft is again in a position between the shed closing position and the second operational reversal point, in particular the deep shed position. This allows the phases of reaching the first and second operational reversal points to be controlled separately. For example, the change in the speed curve or the motion profile from which this speed curve is derived can be controlled separately.The motion profile in the area of ​​the upper compartment position affects not only reaching the compartment closing position, but also reaching the second operational reversal point. This can be taken into account by a targeted speed setting or by specifying a motion profile in each phase of a motion cycle.

[0029] It is also advantageous if the speed curve or the predetermined motion profile from which this speed curve is derived is changed only at or after reaching the shed closing position following the end time of the weft insertion, at which the weft shaft 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 motion profile from which this speed curve is derived is changed before or until the next reaching of the shed closing position after the weft shaft 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 slot closure time and the time integral over the speed modification between the second and third slot closure time cancel each other out (i.e. have the same magnitude but differ in sign), the slot stroke remains unchanged.

[0031] Furthermore, it is also advantageous to adjust the height of the shed end position depending on the pattern, particularly by adjusting it individually, to accommodate the specific characteristics of the weave type. The same advantages can be achieved using a dobby loom for carrying out the process, for which patent protection is also claimed. The dobby loom has a control unit for controlling or electronically generating a guide shaft for the dobby loom and for controlling the dobby drives, which is designed to operate the dobby drives according to the described process.

[0032] In a particularly preferred embodiment, the control unit for operating the shaft drives allows the 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 mode with a change of direction of rotation at both operating reversal points. Preferably, this selection can be made individually for each shaft drive.

[0033] In a particularly preferred manner, the selection is carried out automatically by the control unit and preferably based on the requirements of the order to be woven, which include, for example, the type of weave, the desired or economically necessary minimum operating speed, properties of the material and optical effects to be achieved, and / or based on framework data such as specifications for energy consumption or ambient temperature.

[0034] Alternatively, the selection can also be made manually by an operator.

[0035] Further advantages of the invention are described in the following exemplary embodiments. These show:

[0036] Figure 1 shows an overview of a shaft loom in a schematic, partially cut-away side view; Figure 2 shows a schematic representation of a weaving shaft with a shaft drive and a transmission mechanism in a front view.

[0037] Figure 3 shows a schematic representation of a method for forming a web shed according to a first embodiment.

[0038] Figure 4 shows a schematic representation of a method for forming a shed according to a second embodiment.

[0039] Figure 5 shows a schematic representation of a method for forming a web shed according to a third embodiment.

[0040] Figure 6 shows a schematic representation of a method for forming a shed according to a fourth embodiment.

[0041] Figure 7 shows a schematic representation of a method for forming a web shed according to a fifth embodiment.

[0042] Figure 8 shows a schematic representation of a method for forming a shed according to a sixth embodiment.

[0043] Figure 9 shows a schematic representation of a method for forming a shed according to a seventh embodiment, as well as

[0044] Figure 10 is a schematic representation of a conventional method for forming a shed using a continuous shaft drive.

[0045] In the following description of the exemplary embodiments, features that are identical and / or at least comparable in their design and / or function across the various figures are each designated with the same reference numerals. Furthermore, features are generally only explained in detail upon their initial mention, while subsequent exemplary embodiments focus solely on the differences compared to those already described. Unless features are explained in detail again, their design and / or function correspond to the design and function of the features already described with reference to one or more of the preceding figures. For the sake of clarity, often only one or a few identical components or features are labeled.

[0046] Figure 1 shows a shaft loom 1 in a schematic, partially cutaway side view. The shaft loom 1 includes, in a manner known per se, 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 this case by heddles 3, which are movable back and forth between two turning points in a manner also known per se. In the heddles 3, the warp threads 6 are guided in heddles (not named here). In this illustration, only two heddles 3 are shown. In reality, however, depending on the weaving pattern, considerably more heddles 3 may be provided. Furthermore, the shaft loom 1 has a reed 7, with which a inserted weft thread (not named here) can be beaten onto a fabric edge (not named here), as shown by the dashed representation of the reed 7.The weft insertion devices are not shown here and can typically include, for example, one or more grippers, air nozzles, or projectiles. The finished woven fabric 8 is then unwound in the warp direction KR and wound onto a stock beam 9 of the dobby loom 1.

[0047] As mentioned, the weaving shafts 3 are movable between two reversal points. This allows the weaving shafts 3, and thus the warp threads 6 they guide, to be moved alternately from the high shed 15 to the low 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 weaving shaft 3 actually reverses in each movement cycle. These may 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 dashed line. This is the position that the warp threads 6 assume at the shed closure time FS (see Figure 3). At this time, the weaving shafts 3 are in the shed closure position 13 (see Figure 3).

[0048] The shaft loom 1 further comprises a drive 11 for driving the reed shaft 10 or the reed 7. Shaft drives 4 are also provided for driving the heddle shafts 3. As a rule, one shaft drive 4 drives one heddle shaft 3, as will be shown below with reference to Figure 2. However, it is also conceivable that one shaft drive 4 drives several heddle shafts 3. The heddle shaft(s) 3 driven by one shaft drive 4 are movable independently of heddle shafts 3 driven by other shaft drives 4. The shaft drives 4 are operated at least partially synchronously with a guide shaft of the shaft loom 1. The shaft loom further comprises a control unit 17, which controls the shaft drives 4 and, as shown here, also the drive 11 of the reed shaft 10.

[0049] Figure 2 shows a schematic front view of a woven shaft 3 with an associated shaft drive 4 and a transmission mechanism 12, via which the shaft drive 4 drives the woven shaft 3. The transmission mechanism 12 comprises, in a manner known per se, a linkage drive, which in this case includes a crank 21, a connecting rod 22, and deflection levers 19, which raise and lower the woven shaft 3 via connecting rods 23. Furthermore, the transmission mechanism 12 includes a cross member 20 for connecting the two deflection levers 19. The shaft drive 4 can be operated with alternating rotation DR or in continuous operation to move the woven shaft 3 back and forth or up and down between two reversal points. The transmission mechanism 12 defines a first and a second mechanical reversal point MP1, MP2. The first and second mechanical reversal points MP1, MP2 define a maximum possible stroke Hmax of the woven shaft 3.In the present example, the first mechanical reversal point MP1 denotes the highest possible position of the weaving shaft 3, and the second mechanical reversal point MP2 denotes the lowest possible position. The operational reversal points BP1 and BP2 are distinct from the mechanical reversal points MP1 and MP2. These are the points to which the respective weaving shaft 3 actually reverses during a movement cycle. These points BP1 and BP2 are determined by the operating mode of the shaft drive 4 and may differ from or coincide with the mechanical reversal points MP2 and MP2. Furthermore, the position 13 denotes the sheave closing position, which is located between the operational reversal points BP1 and BP2 and is usually positioned midway between them. In the present example, the first operational reversal point BP1 corresponds to the high-fold position, and the second operational reversal point BP2 corresponds to the low-fold position.However, depending on the type and operating mode of the shaft loom 1, this could also be the other way around.

[0050] According to the procedure, the weaving shaft 3 is moved towards the first mechanical reversal point MP1, in this example upwards towards the upright position. Upon reaching the upright position, the shaft drive 4 maintains its direction of rotation DR, so that the weaving shaft 3 passes through the first mechanical reversal point MP1 in the direction of the downright position. The first operational reversal point BP1 of the weaving shaft 3 thus coincides with the first mechanical reversal point MP1 of the weaving shaft 3 in this case. Subsequently, with the shaft drive 4 still in the same direction of rotation, the weaving shaft 3 is moved downwards past the shed closing position 13 towards the second mechanical reversal point MP2, in this case downwards towards the downright position. At the latest upon reaching the second mechanical reversal point MP2, the direction of rotation DR of the shaft drive 4 is then reversed to form the second operational reversal point BP2 of the weaving shaft 3.It is conceivable that the second operational reversal point BP2 coincides with the second mechanical reversal point MP2, namely if the direction of rotation DR of the shaft drive 4 is only reversed upon reaching the second mechanical reversal point MP2. However, it is equally possible to reverse the direction of rotation DR before reaching the second mechanical reversal point MP2. This is illustrated 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 weaving shaft 3 is also smaller than the maximum possible stroke Hmax. As 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, the direction of rotation would be reversed before or at the latest upon reaching the upper mechanical reversal point to establish the upper operational reversal point. Therefore, 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 unidirectional oscillating method enables particularly drive-friendly and flexible operation of the shaft loom 1.

[0051] To further explain the method according to the invention, reference is first made to Figure 10. This figure shows a rotational 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 Figures 1 and 2). The time axis shows cyclically recurring points in time that are important for the weaving process, 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 corresponds to an angle of 360° of the guide shaft of the shaft loom 1. The 180° angles of the guide shaft are also shown. At 180° of the guide shaft, the weaving shaft 3, driven by the shaft drive 4 (see Figures 1 and 2), is either in the up-fold position or in the down-fold position.The vertical axis of the speed-time diagram shows the rotational speed n of the shaft drive 4. The vertical axis of the stroke-time diagram also shows the stroke H of the weaving shaft 3 over time.

[0052] As can be seen from the speed-time diagram in the upper part of Figure 10, the shaft drive 4 is operated at a constant speed n and thus continuously. In this case, both the first mechanical reversal point MP1 and the second mechanical reversal point MP2 are always passed through without a change in 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 weaving shaft 3 (see Figure 2) corresponds to the maximum possible stroke Hmax and is shown as a solid line in the stroke-time diagram in the lower part of Figure 3. With an oscillating shaft drive 4, a similar stroke profile would result, but due to the constant changes in direction of rotation with acceleration and deceleration, it would deviate from a sinusoidal curve.For the following explanation of the inventive one-sided oscillating method with reference to Figures 3 - 9, the course of the stroke H over time t shown in Figure 10 with continuous shaft drive 4 (see Figure 2), in which the actual stroke H reaches the maximum stroke Hmax, shall serve as a reference and is shown there in dashed lines.

[0053] Figure 3 shows a first embodiment of the method for forming a shed 2, illustrated by a speed-time diagram shown in the upper part of Figure 3 and a stroke-time diagram shown below it. The dashed lines again show the stroke H over time when, as illustrated in Figure 10, the actual stroke H reaches the maximum stroke Hmax during a continuous shaft drive 4 (see Figure 2). As can be seen in Figure 3, the shaft drive 4 is operated according to a speed-ramp function during a weft insertion 24, during which the weft shaft 3 is located in the region of the second operational reversal point BP2. In the example shown in Figure 3, this would be while the weft shaft 3 is in the region of the shed 16.This can be achieved by directly or via a motion profile specifying the rotational speed of the shaft drive 4, from which the corresponding rotational speed is derived. In this range, the weaving shaft 3 is operated asynchronously with respect to the guide shaft of the shaft loom 1. This allows the shaft drive 4 to move with uniform acceleration and thus in a manner that protects the drive within the range of the second operating reversal point BP2.

[0054] From the end time ES of this weft entry 24 until the start time SS of the next but one weft entry 24, at which the weft shaft 3 is again in the area of ​​the shed 16, the shaft drive 4 is operated at a constant speed and synchronously with the guide shaft of the dowsing machine. During the weft entry 24 that follows the next but one, as well as during the passage of the weft shaft 3 through the first operational reversal point BP1, the shaft drive 4 is also operated at a constant speed and synchronously with the guide shaft of the dowsing machine 1. In this area, the shaft drive 4 is thus operated in a drive-conserving manner, similar to a continuous drive. Therefore, in contrast to the purely oscillating operation of the prior art, the direction of rotation of the shaft drive 4 is reversed only every second shed change of the weft shaft 3.This avoids high rotational speeds and excessive accelerations of the shaft drive 4, and additionally reduces the load on the shaft drive 4 by eliminating one of the two braking and acceleration phases.

[0055] 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 is located before the second mechanical reversal point MP2. The stroke H of the weaving shaft is thus smaller in this case than the maximum stroke Hmax. 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 therefore smaller than the maximum stroke Hmax and also smaller than the stroke according to Figure 3, as can be seen from the stroke-time diagram shown below. For reference, the course of the stroke H over time is again shown in dashed lines when, as illustrated in Figure 10, the actual stroke H reaches the maximum stroke Hmax with a continuously running shaft drive 4 (see Figure 2).For comparison, the stroke H over time is shown in dashed lines according to Figure 3. The stroke H is adjusted by changing the height of the second operational reversal point BP2. This is achieved according to the method shown in Figure 4 by specifying a particular speed curve or motion profile, from which the speed is derived, to the shaft drive 4 in the region before reaching the second operational reversal point BP2. The shaft drive 4 is thus operated at a speed that differs from the ramp function shown in Figure 3, at least in the region before reaching the second operational reversal point BP2, as can be seen from the speed-time diagram shown at the top of Figure 4. The ramp function of Figure 3 is shown in dashed lines.

[0056] To change or adjust the stroke H of the weaving shaft 3 in this way, the shaft drive 4 is given a slightly lower rotational speed n1.1 or a corresponding movement profile than in the ramp function shown in Figure 3, starting from the start time SS of a shot entry 24, at which the weaving shaft 3 is located in the area of ​​the deep slot 16. This means that the weaving shaft 3 can only travel a slightly shorter distance between the start time SS of the shot entry 24 and the moment the shaft comes to a standstill, so that the second operational reversal point BP2, which in this case corresponds to the deep slot position, shifts even further upwards compared to Figure 3. This allows for a stroke adjustment in the deep slot 16. To return from this upwardly shifted second operational reversal point BP2, the rotational speed n1.2 is correspondingly lower until the end time ES of the shot entry 24.A suitable movement profile is selected.

[0057] Figure 5 shows an embodiment of the process in which the second operational reversal point BP2 is closer to the second mechanical reversal point MP2 than in Figure 3. For reference, the stroke H over time is shown in dashed lines according to Figure 10, and the stroke H over time according to Figure 3 is shown in dashed lines. In this embodiment, the shaft drive 4 is given a slightly higher rotational speed n2.1 than in the embodiment of the process according to Figure 3, or a corresponding motion profile, from the start time SS of a shot entry 24, at which the weaving shaft 3 is located in the area of ​​the trough 16, as can be seen in the rotational speed-time diagram in the upper part of Figure 5. The increased stroke H compared to the stroke H in Figure 3 is clearly visible in the stroke-time diagram in the lower part of Figure 5.To return from the second operational reversal point BP2, which has shifted downwards compared to Figure 3, the rotational speed n2.2 is correspondingly larger or a corresponding motion profile is selected.

[0058] Figure 6 shows a further embodiment of the method in which the height of the compartment closing position 13 has been changed compared to its original position. In the lower stroke-time diagram, the original height of the compartment closing position 13 is shown as a dashed line, and the height of the compartment closing position 13 after the adjustment is shown as a solid line. As can be seen, the compartment closing position 13 has been shifted towards the first mechanical reversal point MP1, in this case, towards the upright compartment position. The stroke H, however, has remained the same as in Figure 3 and is therefore also smaller than the maximum stroke Hmax, which is achieved with continuous shaft drive 4 (see Figure 2) according to Figure 10. 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 for a continuously running shaft drive 4 (see Figure 2). Similarly, the course of the stroke H over time according to Figure 3 is shown here in dashed lines.

[0059] This shift of the shed closure position towards the first mechanical reversal point MP1, while maintaining a constant stroke, can be achieved by, firstly, specifying a speed curve or corresponding movement profile for the shaft drive 4, at least in a region before and / or after reaching the first operational reversal point BP1, such that the speed n3.3, n3.4 is lower than that shown in Figure 3. Secondly, from the start time SS of a weft entry 24, when the weft shaft 3 is located in the region of the shed 16, until the end ES of this weft entry 24, specifying a slightly higher speed n3.1, n3.2 for the shaft drive 4 compared to Figure 3.

[0060] Figure 7 shows another 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 upper compartment position. The stroke H remains the same compared to the stroke H according to Figure 3 (shown with dashed lines), as can again be seen from the stroke-time diagram shown below in Figure 1. The course of the stroke H over time with a continuously running shaft drive 4 (see Figure 2) is also shown here in dashed lines.

[0061] In this example, the height of the shed closing position 13 is modified by specifying a slightly lower rotational speed n4.3, or a corresponding movement profile, for the shaft drive 4 after the end time ES of the weft entry 24, at which the weft shaft is located in the area of ​​the shed 16, until before the start time SS of the next but one weft entry 24, at which the weft shaft 3 is again located in the area of ​​the shed 16. This results in the weft shaft 3 passing through the shed 15 somewhat more slowly. Additionally, from the start time SS to the end time ES of the weft entry 24, at which the weft shaft 3 is located in the area of ​​the shed 16, the shaft drive 4 is given a slightly higher rotational speed (n4.1, n4.2) so that the second operational reversal point BP2 is at the same location as in Figure 3. The stroke H is thus not reduced compared to the embodiment shown in Figure 3.

[0062] The rotational speed n4.3, which differs from that shown in Figure 3, is preferably only specified from the loft closing time FS following a shot entry 24, in which the weaving shaft 3 was in the area of ​​the loft 16, and only until the loft closing time FS before the next shot entry 24, in which the weaving shaft 3 is again in the area of ​​the loft.

[0063] As further shown in Figure 8, it is also possible to adjust the stroke in addition to changing the height of the compartment closing position 13. This is achieved by moving the upper compartment 15 more slowly, corresponding to the rotational speed n5.1 shown here, compared to Figure 3. Unlike Figures 6 and 7, this is not compensated for by a higher rotational speed in other areas. Therefore, both the height of the compartment closing position 13 and the second operational reversal point BP2 are shifted upwards.

[0064] The rotational speed n5.1, which differs from that shown in Figure 3, is preferably only specified in the area between the compartment closing times FS, which include the first operational reversal point BP1.

[0065] As shown in Figure 9, it is of course also possible to shift the height of the compartment locking position 13 not only upwards but also downwards. In the stroke-time diagram shown below in Figure 9, the original position of the compartment locking position 13 is shown as a dashed line and the new position as a solid line.

[0066] As can be seen from the speed-time diagram shown in Figure 9 above, this is achieved by specifying a slightly higher speed n6.3 or a corresponding movement profile to the shaft drive 4 after the end time ES of a shot entry 24, at which the weaving shaft 3 is located in the area of ​​the trough 16, until the start time SS of the next shot entry 24, at which the weaving shaft 3 is again located in the area of ​​the trough. Preferably, the speed n6.3, which differs from that shown in Figure 3, is specified to the shaft drive 4 only in the area between the two shed closing times FS that surround the first operational reversal point BP1.

[0067] Furthermore, from the start time SS to the end time ES of the shot entry 24, at which the woven shaft 3 is located in the area of ​​the deep slot 16, the shaft drive 4 is given a slightly lower rotational speed (n6.1, n6.2) or a corresponding movement profile compared to Figure 3. Thus, the stroke H corresponds to that in Figure 3, as can be seen from the curve of the stroke H over time shown in the lower part of Figure 9.

[0068] The present invention is not limited to the embodiments shown and described. Modifications within the scope of the claims are also possible.

[0069] List of reference signs

[0070] 1 shaft loom

[0071] 2 Webbox

[0072] 3 Web shaft

[0073] 4 shaft drive

[0074] 5 warp beam

[0075] 6 warp threads

[0076] 7 Web sheet

[0077] 8 items

[0078] 9 Warenbaum

[0079] 10 leaf shaft

[0080] 11 Drive of the blade shaft

[0081] 12. Transmission mechanism

[0082] 13 specialist closing position

[0083] 14 Speed ​​curve

[0084] 15 vertical compartments

[0085] 16 deep compartments

[0086] 17 Control unit

[0087] 18 Zero position

[0088] 19 Deflection levers

[0089] 20 girder

[0090] 21 crank

[0091] 22 Connecting rod

[0092] 23 Lifting rod

[0093] 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

[0094] W angle

[0095] H Hub

[0096] H max maximum stroke

[0097] KR warp direction

[0098] DR Direction of rotation

[0099] MP1 first mechanical reversal point MP2 second mechanical reversal point BP1 first operational reversal point BP2 second operational reversal point ES end time shot entry

[0100] SS start time shot entry FS specialist closing time

Claims

P a t e n t a n s p r ü c h e 1. Method for forming a shed (2) on a dobby loom (1) which has a plurality of heddles (3) and a plurality of heddle drives (4), wherein each heddle drive (4) drives at least one of the heddles (3) independently of the other heddles (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 heddle (3) driven by it, and wherein the heddle drive (4) driving the at least one heddle (3) is operated with alternating direction of rotation (DR), characterized in that the at least one heddle (3) is moved in the direction of the first mechanical reversal point (MP1), and upon reaching the first mechanical reversal point (MP1) of the heddle (3), the direction of rotation (DR) of the heddle drive (4) is maintained.such that a first operational reversal point (BP1 ) of the weaving shaft (3) coincides with the first mechanical reversal point (MP1 ) of the weaving shaft (3), that the at least one weaving shaft (3) is moved via a shed closing position (13) in the direction of the second mechanical reversal point (MP2), and that at the latest upon reaching the second mechanical reversal point (MP2) of the weaving shaft (3), the direction of rotation (DR) of the shaft drive (4) is reversed to form a second operational reversal point (BP2) of the weaving shaft (3).

2. Method according to claim 1, characterized in that in regular weaving operation the at least one weaving 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), preferably the steps of claim 1 being repeated cyclically.

3. Method according to claim 1 or 2, characterized in that the first operational reversal point (BP1 ) is the high-pitch position of the weaving shaft (3) and the second operational reversal point (BP2) is the low-pitch position of the weaving shaft (3).

4. Method according to one of claims 1 - 3, characterized in that the shaft drive (4) is operated according to a predetermined speed curve or a predetermined motion profile from which this speed curve results.

5. Method according to one of claims 1 - 4, characterized in that the shaft drive (4) is not operated synchronously with respect to a guide shaft of the shaft weaving machine (1) during the passage through the second operational reversal point (BP2) by the weaving shaft (3).

6. Method according to one of claims 4 or 5, characterized in that the shaft drive (4) is operated on the speed side according to a ramp function during the passage through the second operational reversal point (BP2) by the weaving shaft (3).

7. Method according to one of claims 4 - 6, characterized in that the shaft drive (4) is operated at a constant speed (n) during the passage through the first operational reversal point (BP1) by the weaving shaft (3).

8. Method according to one of claims 4 - 7, characterized in that the shaft drive (4) is operated synchronously to the guide shaft of the shaft weaving machine (1) during the passage through the first operational reversal point (BP1) by the weaving shaft (3).

9. Method according to claim 7, characterized in that the shaft drive (4) is driven from an end time (ES) of a shot entry (24), at which the The weaving shaft (3) was in a position between the compartment closing position (13) and the second operational reversal point (BP2) until a start time (SS) of a shot entry after the next (24), at which the weaving shaft (3) is again in a position between the compartment closing position (13) and the second operational reversal point (BP2) after passing through the first operational reversal point (BP1), is operated at a constant speed (n).

10. Method according to claim 6, characterized in that the shaft drive (4) is operated on the speed side according to a ramp function from a start time (SS) of a weft entry (24), at which the weft shaft (3) is in a position between the shed closing position (13) and the second operational reversal point (BP2), until the end time (ES) of the same weft entry (24), at which the weft shaft (3) is again in a position between the shed closing position (13) and the second operational reversal point (BP2).

11. Method according to one of claims 4-10, characterized in that the height of the second operational reversal point (BP2) is changed by changing the predetermined speed curve or the predetermined motion profile from which this speed curve results in a region before reaching the second operational reversal point (BP2), wherein preferably the predetermined speed curve or the motion profile from which this speed curve results is changed only at or after the start time (SS) of the weft insertion (24), at which the weft shaft (3) is in a position between the shed closure position (13) and the second operational reversal point (BP2).

12. Method according to one of claims 4-11, characterized in that a height position of the compartment closure position (13) is changed by changing the predetermined speed curve or the motion profile from which this speed curve results in a range before and / or after reaching the second operational reversal point (BP2) is changed, wherein preferably the predetermined speed curve or the motion profile from which this speed curve results is changed only at or after the start time (SS) of the shot entry (24), at which the weaving shaft (3) is in a position between the compartment closing position (13) and the second operational reversal point (BP2), and / or wherein preferably the predetermined speed curve or the motion profile from which this speed curve results is changed only before the end time (ES) of the same shot entry (24), at which the weaving shaft (3) is still in a position between the compartment closing position (13) and the second operational reversal point (BP2).

13. Method according to one of claims 4-12, characterized in that the height of the shed closing position (13) is changed by modifying the predetermined speed curve or the predetermined motion profile from which this speed curve results in a region before and / or after reaching the first operational reversal point (BP1), wherein preferably the predetermined speed curve or the predetermined motion profile from which this speed curve results is modified only at or after the end time (ES) of the weft insertion (24), at which the weft shaft (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 motion profile from which this speed curve results is modified before the start time (SS) of the next but one weft insertion (24).in which the web shaft (3) is again in a position between the end position (13) and the second operational reversal point (BP2).

14. Method according to claim 13, characterized in that the rotational speed curve or the predetermined motion profile from which this rotational speed curve results is only displayed at or after reaching the closed position (13) after the end time (ES) of the weft insertion (24), at which the weft shaft (3) is in a position between the compartment closing position (13) and the second operational reversal point (BP2) is changed, and / or that the specified speed curve or the specified motion profile from which this speed curve results is changed before or until the next time the compartment closing position (13) is reached after passing through the first operational reversal point (BP1) by the weaving shaft (3).

15. Method according to one of claims 11 - 14, characterized in that the height position of the second operational reversal point (BP2), and / or the compartment closing position (13) is changed depending on the pattern, in particular is set individually.

16. Shaft weaving machine (1) for carrying out the method according to one of the preceding claims, comprising a plurality of shafts (3) and a plurality of shaft drives (4), wherein each shaft drive (4) drives at least one of the shafts (3) independently of the other 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 shaft (3) driven by it, and wherein the shaft drive (4) is operable with alternating direction of rotation (DR), and comprising a control unit (17) for controlling or electronically generating a guide shaft of the shaft weaving machine (1) and for controlling the shaft drives (4), characterized in that the control unit (17) is configured to operate the shaft drives (4) according to one of the preceding claims.

17. Shaft weaving machine (1) according to claim 16, characterized in 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 in that the operating mode of the shaft weaving machine (1 ) can be selected manually.

19. Shaft weaving machine (1 ) according to claim 17, characterized in that the operating mode of the shaft weaving machine (1 ) can be automatically selected depending on application data.

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