Clamping frame, drawing-in machine comprising such a clamping frame and drawing-in method using such a clamping frame

Abstract

A clamping frame comprises first and second side posts (642, 644) and upper and lower clamping rails (646, 648). Each side post comprises a spindle (652, 654) with a threaded outer surface. The clamping frame comprises two primary nuts (662, 664) in threaded engagement with one of the threaded outer surfaces. At least a first clamping rail is connected to the two primary nuts (662, 664). A primary driving arrangement (800) includes two primary actuators (802, 804) configured to cause a relative rotation between the primary nuts and the spindles. The position of the second clamping rail is not modified by the relative rotation between each primary nut and the respective spindle. From a configuration where the upper and lower clamping rails (646, 648) define a maximum value of a spacing distance (d6) between them, the first clamping rail (646, 648) is movable relative to each spindle to reduce the spacing distance (d6) to a value strictly less than half of the maximum value. The clamping frame comprises a controller for controlling the two primary actuators (802, 804).

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a clamping frame for clamping warp yarns of at least one yarn layer. The present invention also relates to a drawing-in machine for drawing-in warp yarns from at least one yarn layer into a weaving harness and to a drawing-in method. The invention belongs to the field of harness preparation for weaving looms.BACKGROUND OF THE INVENTION

[0002] It is known to use, during weaving harness preparation, a clamping frame for clamping warp yarns of at least one yarn layer obtained from a warp beam.

[0003] In this context, EP4033021A1 discloses a clamping frame formed of an upper clamping rail and a lower clamping rail and two lateral side posts. This clamping frame gives globally satisfaction. The lower clamping rail is mounted on the side posts without possibility of relative movement, whereas the upper clamping rail may move relative to the lateral posts along a vertical axis. The two clamping rails remain parallel to each other. A tensioning device includes rotating spindles, each in threaded engagement with a nut, which cause a vertical movement of the upper clamping rail in order to adjust its position relative to the lower clamping rail and, thus, the tension of the clamped yarns. This tension cannot be automatically and / or locally adjusted during drawing-in. Moreover, the position of the clamping rails relative to the floor cannot be adjusted during drawing-in. When it is needed to tear-down a weaving harness, when all warp yarns have been drawn-in, the lower clamping rail is interposed between the weaving harness elements and the weaving beam. Thus, a tearing-down operation includes several relatively complex steps.

[0004] On the other hand, CN206089969U discloses a clamping frame movable laterally with respect to a supporting rail. This allows a quick tearing-down of the weaving harness after completion of drawing-in. This lateral movement must be implemented in addition to any movement affecting the yarn layer tension before drawing-in.SUMMARY OF THE INVENTION

[0005] The present invention aims at solving these problems by providing a clamping frame allowing accurate adjustment on the position of its clamping rails with respect to its side posts, on a wide range. This allows more efficient layer tensioning, yarn drawing-in and tearing-down.

[0006] With this respect, the present invention relates to a clamping frame for clamping warp yarns of at least one yarn layer, the clamping frame comprising at least: first and second side posts; an upper clamping rail and a lower clamping rail configured for clamping the warp yarns of the at least one yarn layer, the first and second side posts mechanically connecting the upper and lower clamping rails together, the upper and lower clamping rails extending between the first and second side posts and being spaced along a transverse axis.

[0007] According to the invention the first side post comprises a first spindle with a first threaded outer surface centered on a first longitudinal axis; the second side post comprises a second spindle with a second threaded outer surface centered on a second longitudinal axis; the first longitudinal axis and the second longitudinal axis are parallel to the transverse axis, have a fixed position relative to one another and together define a main plane; the clamping frame comprises two primary nuts, each primary nut being in threaded engagement with one of the first threaded outer surface and the second threaded outer surface respectively; at least a first clamping rail, among the upper and lower clamping rails, is mechanically connected to the two primary nuts, so that a movement of each primary nut with regard to the respective spindle in a direction parallel to the transverse axis causes a movement of the first clamping rail with regard to the respective spindle in a direction parallel to the transverse axis and the first clamping rail has no possibility of translational movement relative to the primary nuts along an axis perpendicular to the main plane; the clamping frame comprises a primary driving arrangement including two primary actuators, each primary actuator being configured to cause a relative rotation, around the respective first or the second longitudinal axis, between the respective primary nut and the respective spindle, the position of the second clamping rail, among the upper and lower clamping rails, along the transverse axis relative to the first and second spindles is not modified by the relative rotation between each primary nut and the respective spindle; from a configuration where the positions of the upper and lower clamping rails along the transverse axis with regard to the first and second spindles define a maximum value of a spacing distance between the upper clamping rail and the lower clamping rail along the transverse axis, the first clamping rail is movable relative to each spindle along the transverse axis to reduce the spacing distance to a value strictly less than half of the maximum value of the spacing distance; the clamping frame comprises a controller for controlling the two primary actuators.

[0008] Thanks to the invention, the two primary actuators of the primary driving arrangement are dedicated to the first clamping rail and allow a fine adjustment of its position along the transverse axis, on a wide range, thanks to the cooperation between the two primary nuts and the two spindles. This confers ergonomics advantages to the clamping frame. Moreover, as the controller controls the two first actuators, it is possible to finely adjust the position of the first clamping rail along the transverse axis during drawing-in.

[0009] According to advantageous and optional aspects of the invention, such a clamping frame may incorporate one or several of the following features: Each primary nut is mounted on a primary support without possibility of translational movement between the primary nut and the primary support, in a direction parallel to the transverse axis and in all directions perpendicular to the transverse axis, whereas each primary support cooperates with a guide member of the adjacent side post, the guide member extending parallel to the transverse axis and blocking the primary support in rotation around the respective longitudinal axis and whereas each longitudinal end of the first clamping rail is articulated on a primary support so that a longitudinal axis of the first clamping rail has a possibility of tilting movement with regard to the transverse axis. Thanks to this aspect of the invention, the two longitudinal ends of the first clamping rail may be individually driven by one of the first actuators and the tilting of the first clamping rail allows adjusting the tension in the yarn layer, along the direction of the main longitudinal axis. The side posts and the clamping rails form a deformable quadrangle, with at least two corners with variable angles. An articulation axis of one longitudinal end of the first clamping rail with regard to the respective primary support is perpendicular to the main plane and stationary relative to the first clamping rail and to the respective primary support. The other longitudinal end of the first clamping rail comprises an articulation recess which cooperates, in a direction parallel to the transverse axis, with a cylindrical pin of the respective primary support, the cylindrical pin being centered on an articulation axis perpendicular to the main plane and the articulation recess having an oblong shape with a larger dimension in a direction parallel to the longitudinal axis of the first clamping rail. Each primary nut is mechanically connected to the first clamping rail with a possibility of relative rotation around the respective first longitudinal axis or second longitudinal axis; each primary actuator is secured to the respective primary nut, at least along the transverse axis and each primary actuator is configured to rotate the respective primary nut with regard to the first clamping rail and to the respective spindle around the respective longitudinal axis. The primary driving arrangement is co-moved with the first clamping rail, providing more versatility for the positioning of the first clamping rail with regard to the second clamping rail. The primary driving arrangement includes at least one brake configured to selectively oppose a relative rotation between a primary nut and the respective spindle. The brake brings a safety feature and avoids undesired movements of the first clamping rail. The first and the second spindles are secured with mounting bases of the side posts without possibility of rotation around the respective first longitudinal axis or second longitudinal axis. Thanks to this aspect of the invention, the spindles are fixed around the first and second longitudinal axis, which provides a higher stiffness for the clamping frame. The second clamping rail is mechanically connected to two secondary nuts, each secondary nut being in threaded engagement with one of the first threaded outer surface and the second threaded outer surface respectively. The second clamping rail is mechanically connected to the two secondary nuts, so that a movement of the secondary nut with regard to the respective spindle in a direction parallel to the transverse axis causes a movement of the second clamping rail with regard to the respective spindle in a direction parallel to the transverse axis and the second clamping rail has no possibility of translational movement relative to the secondary nuts along an axis perpendicular to the main plane. The clamping frame comprises a secondary driving arrangement which includes at least one secondary actuator configured to cause at least a relative rotation, around the respective first or the second longitudinal axis, between a secondary nut and the respective spindle. The first threaded outer surface and the second threaded outer surface extend continuously from the respective primary nut to the respective secondary nut and the controller is configured to control the at least one secondary actuator. Thanks to this aspect of the invention, the second clamping rail is also movable relative to the spindles, along the first and second longitudinal axes. This provides more versatility for the clamping frame, which can adapt to many configurations of use. The same spindles are in engagement with the primary and secondary nuts for compactness. The clamping frame also comprises an outer frame with two vertical stands configured to stand on a ground, wherein the first and second side posts and the upper and lower clamping rails are mounted on the outer frame, between the two vertical stands, with a possibility of tilting movement of the main plane relative to the two vertical stands, around a pivoting axis. The pivoting axis is perpendicular to the transverse axis, fixed in position with respect to the outer frame, and situated between the ground and the lower clamping rail along the transverse axis. The tilting capacity of the main frame, thus of the side posts and of the two clamping rails, allows inclining, with low forces, the clamping rails together to the front side or to the back side relative to the outer frame, in a variable way, in order to adapt to the cooperation with the drawing-in unit. The clamping frame comprises an upper crossbeam, which extends above the upper clamping rail when the upper clamping rail is in the position with regard to the first and second spindles along the transverse axis defining the maximum value of the spacing distance between the upper clamping rail and the lower clamping rail. The upper crossbeam is equipped with connection means for connection to a drawing-in unit and / or to another clamping frame. The connection between the clamping frame and the drawing-in unit or between the clamping frame and the other clamping frame does not limit ergonomics, in particular during drawing-in and tearing down phases implemented with the clamping frame. The clamping frame includes at least one sensor configured to detect a relative position between a nut and the respective spindle, the sensor being connected to the controller. The sensor gives the possibility to memorize some dedicated positions of the nut along the longitudinal axis of the corresponding spindle and to control the actuator to quickly, precisely and reliably reach these positions. The first clamping rail is the lower clamping rail and a volume defined between the first and second side posts and below the lower clamping rail is free from a crossbeam mechanically connected to first and second side posts or cables extending between the first and second side posts. The free volume defined below the lower clamping rail facilitates movements of the drawing-in unit, of the operator and / or of the weaving harness along and through the clamping frame. The height of this volume can be increased by raising the lower clamping rail. In case only one clamping rail is movable along the spindles, with respect to the side posts, this movable clamping rail is advantageously the lower clamping rail, in order to allow increasing the height of the free volume. The clamping frame includes a carriage removably mounted on the first clamping rail and configured for supporting a weaving harness so that the weaving harness is co-moved with the first clamping rail relative to the first and second spindles along the transverse axis by the primary driving arrangement. The carriage supporting the weaving harness can be lifted by the clamping frame during tearing-down, for more ergonomics.

[0010] According a second aspect, the invention relates to a drawing-in machine for drawing-in warp yarns from at least one yarn layer into a weaving harness including at least one clamping frame as previously described; a drawing-in unit equipped at least with ∘ a yarn separation device configured to separate a warp yarn from the at least one yarn layer clamped in the clamping frame; ∘ a threading device configured to draw-in each separated warp yarn through the weaving harness.

[0011] This drawing-in machine induces the advantages mentioned here above regarding the clamping frame.

[0012] According to a third aspect, the invention relates to a drawing-in method for drawing-in warp yarns from at least one yarn layer into a weaving harness, using a clamping frame as described above and a drawing-in unit equipped at least with ∘ a yarn separation device configured to separate a warp yarn from at least one yarn layer clamped in the clamping frame; and ∘ a threading device configured to draw-in each separated warp yarn through the weaving harness, whereas the method includes at least the following successive steps consisting in: a) preparing the at least one yarn layer from a weaving beam by clamping the warp yarns on the upper and lower clamping rails of the clamping frame ; b) drawing-in warp yarns from the at least one yarn layer into the weaving harness; and c) tearing-down the weaving harness drawn-in with warp yarns, from a front side to a back side of the main plane and whereas the controller of the clamping frame controls the at least two primary actuators in order to place the first clamping rail at a first position along the transverse axis during one of the steps a), b) or c) and at a second position along the transverse axis during another step among steps a), b) or c), the first and second positions being different positions and being each defined with regard to the position of each primary nut with regard to the respective spindle along the transverse axis.

[0013] This method is particularly efficient for the preparation of a weaving harness.

[0014] Advantageously the controller of the clamping frame includes a memory; several different dedicated positions of the first clamping rail are stored in the memory of the controller, each dedicated position being defined with regard to the position of each primary nut with regard to the respective spindle along the transverse axis, the controller controls the at least the two primary actuators in order to place the first clamping rail in one of the dedicated positions. The memorization of the different dedicated positions makes the method much faster.

[0015] According to another optional aspect the drawing-in unit is equipped with a yarn separation detection device connected to the controller and configured to detect a result of the yarn separation performed by the yarn separation device; and during step b), at least one of the primary actuators is controlled by the controller, depending on a signal received by the controller from the yarn separation detection device, to adjust the position of the first clamping rail with regard to the first and second spindles along the transverse axis. Thanks to this aspect of the invention, the yarn separation may be improved, in real time in particular during step b), by taking into account the result of each action of the yarn separation device.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention will be better understood, based on the following description, given as a non-limiting example and made in reference to the following figures: [Fig. 1] Figure 1 is a front view of a clamping frame according to a first embodiment the invention, in a preparation configuration; [Fig. 2] Figure 2 is a side view of the clamping frame of figure 1, where a left vertical stand is represented in dotted lines for showing other components of the clamping frame; [Fig. 3] Figure 3 is a back view of the clamping frame of figures 2 and 3; [Fig. 4] Figure 4 is an enlarged partial cut view along line IV-IV on figure 3; [Fig. 5] Figure 5 is a perspective back view of the clamping frame of figures 1 to 4; [Fig. 6] Figure 6 is a partial perspective view of the clamping frame of figures 1 to 5 corresponding to detail VI on figure 5, seen from another angle; [Fig. 7] Figure 7 is a sectional view of the clamping frame of figures 1 to 6 along line VII-VII on figure 5; [Fig. 8] Figure 8 is an enlarged view of detail VIII on figure 7; [Fig. 9] Figure 9 is an enlarged view of detail IX on figure 7; [Fig. 10] Figure 10 is a side view similar to figure 2, when the clamping frame is in a drawing-in configuration; [Fig. 11] Figure 11 is a front view comparable to figure 1, showing tilting of the clamping rails; [Fig. 12] Figure 12 is a side view similar to figure 2, at the beginning of a tearing-down phase; [Fig. 13] Figure 13 is a side view similar to figure 2, at the end of the tearing-down phase; [Fig. 14] Figure 14 is a back view of a clamping frame according to a second embodiment of the invention; [Fig. 15] Figure 15 is a horizontal cut view along line XV-XV on figure 14 and; [Fig. 16] Figure 16 is a sectional view comparable to figure 7, for a clamping frame according to a third embodiment of the invention. DETAILED DESCRIPTION OF SOME EMBODIMENTS

[0017] A drawing-in machine 2 according to the invention is represented on figure 10 and includes, amongst others, a drawing-in unit 4 and a clamping frame 6. This clamping frame 6 is also represented on figures 1 to 9 and 11 to 13.

[0018] The front side of the clamping frame 6 is visible on figure 1 and its back side is visible on figures 3 and 5. The front side of the clamping frame faces the drawing-in unit and its backside faces a weaving beam B during when drawing-in takes place.

[0019] The drawing-in unit 4 includes a unit controller 42 and a yarn separation device 44, such as yarn suction means known from WO02088445A2, configured to separate a warp yarn Y from a yarn layer L1. The drawing-in unit 4 also includes a yarn detection device 46, such as a camera, configured to detect the result of the yarn separation performed by the yarn separation device 44. In particular, the yarn separation detection device 46 is capable of detecting if a single warp yarn has been separated from the yarn layer L1 by the yarn separation device 44.

[0020] The drawing-in unit 4 also includes a non-represented threading device configured to draw a separated warp yarn through elements of a weaving harness 8. Such elements are, for instance, a dropwire, as shown by a group of dropwires 82 on figures 10, 12 and 13, a heddle, as shown by a group of heddles 84, and / or a reed 86.

[0021] The clamping frame 6 also includes a carriage 10 removably mounted on a clamping rail 646 or 648 and configured for supporting the weaving harness 8 after its elements have been drawn-in with separated yarns Y, as represented on figure 12.

[0022] The drawing-in machine 2 also includes a non-represented transport device for moving the drawing-in unit 4 relative to the clamping frame 6 along a longitudinal direction which is parallel to a main longitudinal axis A6 of the clamping frame 6.

[0023] In the first embodiment of the invention represented on figures 1 to 13, the clamping frame 6 stands on a surface S of the ground G of a drawing-in room, as represented on figure 1 only.

[0024] The clamping frame 6 includes an outer frame 62 fixed on the ground G during drawing-in. In other words, the outer frame 62 is static in the drawing-in room during drawing-in. The outer frame 62 includes a left vertical stand 622, a right vertical stand 624 and a horizontal upper crossbeam 626, which extends parallel to the main longitudinal axis A6, from the left vertical stands 622 to the right vertical stand 624. The outer frame 622 does not include a lower crossbeam, which would extend close to the ground G, between the two vertical stands 622 and 624.

[0025] Right and left directions are defined with regard to main longitudinal axis A6 and with the orientation of figure 1.

[0026] Each vertical stand 622 or 624 is provided with a lower sole 628 immobilized on the ground G by fixing means, such as screws represented by a longitudinal axis 629 on figures 1 and 2 only.

[0027] The outer frame 62 supports a sub-frame 64, a controller 66 and a display screen 68.

[0028] Advantageously, the controller 66 is formed of a printed circuit board equipped with electronic components and integrated within one of the vertical stands 622 and 624, the left stand 622 in the example of the figures. The display screen 68 may be located on the external side face of one of items 622, 624, on the external front face of the left vertical stand 622 in the example of the figures. For the sake of simplicity, the controller 66 and the display screen 68 are represented on figures 1, 6 and 10 only.

[0029] The controller 66 includes a memory 166 for storing data corresponding to some positions of some elements of the clamping frame 6, as explained here below.

[0030] The display screen 68 enables an operator to monitor operation of the clamping frame 6 and, possibly, of the drawing-in unit 4. It may be a touch screen, which allows the operator to give instructions to the controller 66 through this screen.

[0031] The sub-frame 64 includes a left side post 642 and a right side post 644. Side posts 642 and 644 respectively form first and second side posts and are parallel to each other.

[0032] B6 denotes a transverse axis of the clamping frame 6, which is perpendicular to the main longitudinal axis A6 and, in the example of figures 1 to 13, globally vertical. By globally vertical, one means that the transverse axis B6 is vertical or slightly inclined relative to a vertical axis Z6. By slightly inclined, one means that the transverse axis B6 can be inclined up to 3°, preferably up to 10°, toward the front side of the clamping frame 6, or up to 8°, preferably up to 10°, toward the back side of this clamping frame 6. In the configuration of figures 1 to 9, the transverse axis B6 is strictly vertical. In a drawing-in configuration shown on figure 10, the transverse axis B6 is tilted toward the front side of the clamping frame 6 with respect to the vertical axis Z6. Actually, the orientation of the transverse axis B6 can adapt and this axis can be tilted to the front or to the back, in particular by + / - 3°. The configuration represented on figure 10 is one of the possible drawing-in configurations of the drawing-in machine 2. In the configurations of figures 12 and 13, the transverse axis B6 is tilted toward the back side of the clamping frame 6 with respect to the vertical axis Z6.

[0033] The sub-frame 64 also includes an upper clamping rail 646 and a lower clamping rail 648. The lower clamping rail 648 extends closer to the ground G than the upper clamping rail 646, with respect to the vertical axis Z6. Each clamping rail 646 or 648 extends along a respective longitudinal axis A646 or A648, between the first and second side posts 642 and 644. The first and second side posts 642 and 644 mechanically connect the upper and lower clamping rails 646 and 648 together.

[0034] Generally speaking, the axes A6, A646 and A648 are globally parallel, i.e. parallel or forming between them an angle of less than 10°. The axes A6, A646 and A648 are parallel in the configuration of figures 1 to 10. However, they can also be slightly tilted or inclined with respect to each other, as shown in figure 11 and explained here below. Preferably each of the axes A646 and A648 may incline + / - 5° from a horizontal direction.

[0035] The upper and lower clamping rails 646 and 648 are spaced along the transverse axis B6, by a spacing distance d6 measured parallel to this axis. The spacing distance d6 is a transverse span between the two clamping rails, at a given longitudinal level along the main longitudinal axis A6, for instance midway between the two side posts 642 and 644.

[0036] The left or first side post 642 comprises a first pole 651 and a first spindle 652, parallel to each other. The first spindle 652 extends along a first longitudinal axis B652, parallel to the transverse axis B6.

[0037] On the other hand, the right or second side post 644 comprises a second pole 653 and a second spindle 654, parallel to each other. The second spindle 654 extends along a second longitudinal axis B654, which is always parallel to the first longitudinal axis B652.

[0038] The first longitudinal axis B652 and the second longitudinal axis B654 have a fixed position relative to one another. They are offset along the main longitudinal axis A6 and together define a main plane P6 of the clamping frame 6. The transverse axis B6 is included in the main plane P6 and parallel to the first and second longitudinal axes B652 and B654 and located midway between these two longitudinal axes.

[0039] The left and right vertical stands 622 and 624 of the outer frame 62 and the first and second poles 651 and 653 are located out of a volume defined between the first and second longitudinal axes B652 and B654.

[0040] Each side post 642 or 644 also includes a lower mounting base 656 and an upper mounting base 658. Each spindle 652 or 654 extends from the lower mounting base 656 to the upper mounting base 658 of the corresponding side post 642 or 644 and it is secured with these mounting bases and with the adjacent pole 651 or 653, in rotation around the respective first or second longitudinal axis B652 or B654 and along the transverse axis B6. Securing of the spindle 652 or 654 with the adjacent pole 651 or 653 in rotation around the respective first and second axes B652 and B654 is obtained by a locking pin 660, which extends through each lower mounting base 656 and through the corresponding spindle 652 or 654 engaged in this mounting base 656. The lower mounting bases 656, the upper mounting bases 658 and the poles 651, 653 of the clamping frame 6 cannot move with respect to each other.

[0041] In a non-represented variant of the invention, the locking pin 660 can be provided at the level of the upper mounting base 658, or two locking pins are provided, respectively at the level of the lower and upper mounting bases.

[0042] A linear rail 666 is formed along each side post 642 or 644 and extends parallel to the transverse axis B6, between the two mounting bases 656 and 658. Each linear rail 666 forms a guide member belonging to the pole 651 or 653 of the side post 642 or 644 and is fixed in rotation around the respective first longitudinal axis B652, B654.

[0043] Advantageously, the linear rail 666 is provided and extends on one external face of the first or second pole 651 or 653, between this pole and the adjacent spindle 652 or 654 and along the main longitudinal axis A6.

[0044] Advantageously, the linear rail 666 extends on the whole length of the first or second pole 651 or 653, taken along the transverse axis B6.

[0045] Advantageously, the first and second spindles 652 and 654 are identical. Thus, the description of one of these spindles applies to the other one.

[0046] The first spindle 652 has a continuous outer threaded surface S652 centered on the first longitudinal axis B652, whereas the second spindle 654 has a continuous outer threaded surface S654 centered on the second longitudinal axis B654. The continuous threaded outer surface S652, respectively S654, has a constant pitch.

[0047] Thanks to the locking pin 660, the outer threaded surface S652 and the outer threaded surface S654 have no possibility of rotation around the first longitudinal axis B652, respectively the second longitudinal axis B654, in particular with regard to the mounting bases 656, 658 and to the outer frame 62.

[0048] A first primary nut 662 is mounted around the first spindle 652, in threaded engagement with its threaded outer surface S652. The first longitudinal axis B652 is a rotation axis for the first primary nut 662 with regard to the first spindle 652. The first primary nut 662 is secured with the first spindle 652 in all directions perpendicular to the first longitudinal axis B652.

[0049] A second primary nut 664 is mounted around the second spindle 654, in threaded engagement with its threaded outer surface S654. The second longitudinal axis B654 is a rotation axis for the second primary nut 662 with regard to the second spindle 654. The second primary nut 664 is secured with the first spindle 654 in all directions perpendicular to the first longitudinal axis B654.

[0050] Advantageously, the primary nuts 662 and 664 are identical.

[0051] Generally speaking, the threaded outer surface S652 extends, on the first spindle 652 and along the first longitudinal axis B652, continuously at least from the level of the first primary nut 662 to the level of the lower clamping rail 648, in all positions of the clamping rails 646 and 648. Similarly, the threaded outer surface S654 extends, on the second spindle 654 and along the second longitudinal axis B654, continuously at least from the level of the second primary nut 664 to the level of the lower clamping rail 648, in all positions of the clamping rails 646 and 648. Unless otherwise specified, a level corresponds to a height measured from the surface S of the ground G, parallel to the vertical axis Z6.

[0052] L6 denotes the length of a spindle 652 or 654 measured along its longitudinal axis B652 or B654. The length L6 is 0.9 to 1.1 times the length of the side posts 642, 644 along the transverse axis B6. Advantageously, the continuous threaded outer surface S652, respectively S654, of a spindle extends on at least 90% of its length L6, preferably at least 95% of this length L6. Preferably, the continuous threaded outer surface S652, respectively S654, of a spindle extends on at least 90% of the length of the side posts 642, 644 along the transverse axis B6.

[0053] A longitudinal movement of each primary nut 662 or 664 along the first or second longitudinal axis B652 or B654 is possible via a relative rotation between each primary nut and the corresponding spindle.

[0054] The amplitude or range of this movement depends on the length of the threaded outer surfaces S652 and S654. Since each of these threaded outer surfaces extends at least between the primary nut 662 or 664 and the lower clamping rail 648, preferably on at least 90% of the length L6, this amplitude or range of movement is close to the total length L6 of the spindles.

[0055] Each primary nut 662 or 664 is mounted on a respective primary support, with no possibility of translational movement between the nut and the corresponding primary support, in a direction parallel to the transverse axis B6 and in all directions perpendicular to the transverse axis B6. More precisely, the first primary nut 662 is secured to a first primary support 672 in a direction parallel to the transverse axis B6, with a possibility of rotation of the first primary nut 662 with respect to the first primary support 672 around the first longitudinal axis B652. Moreover, the second primary nut 664 is secured to a second primary support 674 in a direction parallel to the transverse axis B6, with a possibility of rotation of the second primary nut 664 with respect to the second primary support 674 around the second longitudinal axis B654.

[0056] The left and right longitudinal ends of the upper clamping rail 646 are respectively articulated on the first primary support 672 and on the second primary support 674. The upper clamping rail 646 has no possibility of translational movement relative to the first and second primary nuts 662, 664 along an axis perpendicular to the main plane P6.

[0057] Each clamping rail 646 or 648 is equipped with a clamping profile 676, which extends parallel to the longitudinal axis A646 or A648. The only possibility of movement of the clamping profile 676 with regard to the clamping rail 646 or 648 is along the longitudinal axis A646 or A648. Preferably, as proposed by the first embodiment, the clamping profile 676 has no possibility of movement with regard to the clamping rail 646 or 648. A clamping rod 678 is received within each clamping profile 676. Each clamping rail 646 or 648 is configured to clamp the yarns Y of the yarn layer L1 within the corresponding clamping profile 676 thanks to the clamping rod 678. The teachings of EP4033021A1 can be used for the construction and use of the clamping rails 646 and 648.

[0058] The two primary supports 672 and 674 are symmetrical relative to one another with respect to a plane perpendicular to the main longitudinal axis A6 and including the transverse axis B6.

[0059] The first primary support 672 is described here below. Its description can be transposed to the second primary support 674, by symmetry.

[0060] The first primary support 672 comprises an L shape armature 722, which supports, on one of its outer surfaces, a skid 724 forming a groove. Such a groove is visible on figure 4 for another support 1674. The groove of the skid 724 is configured to accommodate the linear rail 666 and the skid 724 can slide along this rail, in a direction parallel to the transverse axis B6. Thus, the first primary support 672 is guided along the linear rail 666, along a direction parallel to the transverse axis B6 and to the first longitudinal axis B652. The respective shapes of the linear rail 666 and the skid 724 are such that the first primary support 672 can only move parallel to the axes B6 and B652 with respect to the first side post 642. In particular, the first primary support 672 is blocked in rotation with regard to the first pole 651 around an axis parallel to the transverse axis B6, such as the first longitudinal axis B652 or a longitudinal axis B653 of the second pole 653.

[0061] The main plane P6 is a plane of symmetry of the linear rail 666 and of the groove of the skid 724.

[0062] The first primary support 672 also includes a transverse plane bracket 726, which is perpendicular to the first longitudinal axis B652. A parallelepiped box 728, fixed on the bracket 726, also belongs to the first primary support 672.

[0063] A first primary actuator 802 is secured to the first primary support 672, at least along the transverse axis B6. In other words, the first primary actuator 802 is co-moved with the first primary support 672 parallel to the transverse axis B6.

[0064] The first primary actuator 802 includes an electric motor 806, a belt 807 and a pulley 808 fast in rotation with the first primary nut 662. 806A and 806B respectively denote an output shaft and a splined head of the electric motor 806 which form the mobile parts of the electric motor 806. The fixed part of the electric motor 806 is secured to the first primary support 672 in all directions, for example secured with screws. The output shaft 806A of the electric motor 806 extends parallel to the first longitudinal axis B652 and rotates with the splined head 806B with regard to the first primary support 672 around an axis parallel to the transverse axis B6.

[0065] Items 806A and 806B allow the electric motor 806 to drive the belt 807 when the electric motor 806 is supplied with electric power. Thus, the first primary actuator 802 is configured to rotate the first primary nut 662 around the first longitudinal axis B652 with regard to the first spindle 652.

[0066] For instance, the motor 806 is a step motor. Other types of motor may also be considered.

[0067] A first primary brake 902 is also mounted on the first primary support 672 and includes a splined shaft 906 mounted around the spindle 652 and a first jaw 907 fast in rotation with the splined shaft 906. The first jaw 907 forms a brake plate. Advantageously, the first jaw 907 is provided with inner splines 907A in meshing engagement with outer splines 906A of the splined shaft, which secures parts 906 and 907 together, in rotation around the first longitudinal axis B652.

[0068] The first primary brake 902 also includes a second jaw 908, fixed with the primary support 672 in rotation around the first longitudinal axis B652 and axially mobile along this axis with regard to the primary support 672. Movements of the second jaw along the first longitudinal axis B652 are controlled by a non-represented coil.

[0069] A bearing 909 holds the splined shaft 906 within the box 728, with a possibility of rotation around the first longitudinal axis B652.

[0070] The spindle 652 crosses the nut 662, the splined shaft 906, the bracket 726, the jaws 907 and 908 and the bearing 909.

[0071] The first primary nut 662, the pulley 808 and the splined shaft 906 are secured in rotation around and in translation along the first longitudinal axis B652 via several screws 910. Thus, the primary nut 662 and the splined shaft 906 rotate together around the first longitudinal axis B652 when they are driven by the pulley 808, under the action of the motor 806 and the belt 807 of the first primary actuator 802.

[0072] By default, when the coil of the first primary brake 902 is not supplied with electric power, the first jaw 907 is clamped by the mobile jaw 908 and the first primary brake 902 opposes a rotational relative movement between the jaws 907 and 908, thus between the splined shaft 906 and the first primary support 672 around the first longitudinal axis B652. A non-represented elastic member, such as a spring, pushes the second jaw 908 against the first jaw 907, which, in case of a failure of the electric power, immobilizes the first jaw 907 in rotation around the first longitudinal axis B652. In other words, the second jaw 908 is configured to be moved by the elastic member, from a disengaged position, where it allows rotation of the first jaw 907 relative to the primary support 672, around the first longitudinal axis B652, into an engaged position, where it secures the first jaw 907 with the primary support 672, around the first longitudinal axis B652. The result is that the nut 662, connected to the first jaw 907 by the screws 910, is also immobilized, in rotation around the first longitudinal axis B652, through the splined shaft 906 and the screws 910. Thus, due to the connection between the first primary nut 662 and the adjacent splined shaft 906, the first primary brake 902 selectively oppose s in case of a failure of the electric power, the rotation of the first primary nut 662 with regard to the first spindle 652 around the first longitudinal axis B652. In other words, the brake 902 selectively opposes a relative rotation between the primary nut 662 and the spindle 652.

[0073] A position sensor 912 is mounted around the first primary nut 662 and allows determining instantaneous angular position between the first spindle 652 and the first primary nut 662 around the first longitudinal axis B652.

[0074] The position sensor 912 is, for instance, a resolver. It is connected by a connector 914 to an electrical signal transmission line L914, which conveys the output signal S912 of the position sensor 912 to the controller 66.

[0075] The controller 66 is connected to the first primary actuator 802 by a second signal transmission line L802. A control signal S802 for the actuator 802 is sent by the controller 66 to the actuator 802, via this signal transmission line.

[0076] Moreover, a third signal transmission line L902 connects the controller 66 to the first primary brake 902 and allows conveying a control signal S902 for the first primary brake 902, in particular an electric power supply for its coil.

[0077] The left end of the upper clamping rail 646 is mechanically connected with the first primary support 672 next to the left or first side post 642, in particular on the armature 722 of the primary support 672, via a cylindrical pin 686. The cylindrical pin 686 is press-fitted in the armature 722 of the first primary support 672 and a screw 687 screwed in the cylindrical pin 686 secures the upper clamping rail 646 with the first primary support 672 along a lateral axis C6 perpendicular to main plane P6. An articulation recess 696 is provided on the upper clamping rail 646, at the left end of the upper clamping rail and receives the cylindrical pin 686. A686 denotes a central axis of the cylindrical pin 686, which forms an articulation axis of the first primary support 672 with regard to the clamping rail 646. Articulation axis A686 is parallel to the lateral axis C6. Articulation axis A686 is stationary with regard to the first primary support 672.

[0078] The second primary support 674 is made of parts 722, 724, 726 and 728 similar to the ones of the first primary support 672. A second primary actuator 804 is secured to the second primary support 674, at least in along the transverse axis B6. In other words, the second primary actuator 804 is co-moved with the second primary support 674 parallel to the transverse axis B6.

[0079] The second primary actuator 804 includes an electric motor 806 with an output shaft 806A, a splined head 806B, a belt 807 and a pulley 808 fast, in rotation and in translation with regard to the second longitudinal axis B654, with the second primary nut 664. Items 806, 806A, 806B, 807 and 808 are not represented specifically on the figures for the second primary actuator 804. They are respectively identical to items of the first primary actuator 802 bearing the same reference. Thus, the second primary actuator 804 is configured to rotate the second primary nut 664 around the second longitudinal axis B654 with regard to the second spindle 654.

[0080] A second primary break 904 is provided, with the same structure as the first primary brake 902.

[0081] Screws 910, a position sensor 912 and a connector 914 are provided, as for the left extremity of the upper clamping rail 646.

[0082] The right end of the upper clamping rail 646 is mechanically connected with the second primary support 674 next to the right or second side post 644, in particular on the armature 722 of the primary support 674, via a cylindrical pin 688. The cylindrical pin 688 is press-fitted in the second primary support 674. An articulation recess 698 is provided at the upper clamping rail 646, at the right end of the upper clamping rail. A688 denotes a central axis of the cylindrical pin 688, which forms an articulation axis of the second primary support 674 with regard to the upper clamping rail 646. Articulation axis A688 is parallel to lateral axis C6. Articulation axis A688 is stationary with regard to the upper clamping rail 646.

[0083] A primary driving arrangement 800 includes the two primary actuators 802 and 804, which are configured to cause a relative rotation, around the first and second longitudinal axes B652 and B654, between the primary nuts 662 and 664, on the one hand, and the spindles 652 and 654, on the other hand. The primary driving arrangement 800 also includes the two primary brakes 902 and 904.

[0084] It is possible to move the upper clamping rail 646 along the transverse axis B6 with regard to the side posts 642, 644 by proper control of the first and second primary actuators 802 and 804 of the primary driving arrangement 800, via the controller 66. A movement of each primary nut 662, 664 with regard to the respective spindle 652, 654 causes a movement of the upper clamping rail 646 with regard to the respective spindle 652, 654 along the respective longitudinal axis B652, B654. This movement of the upper clamping rail 646 occurs independently of a possible movement of the lower clamping rail 648 with regard to the side posts 642, 644 along the transverse axis B6, the lower clamping rail 648 remaining stationary or moving during the displacement of the upper clamping rail.

[0085] In particular, as the first and second spindles 652, 654 don't move relative to the lower clamping rail 648 during this displacement, the position of the lower clamping rail 648 along the transverse axis B6 is not modified by the relative rotation between the first primary nut 662 and the first spindle 652, on the one hand, and between the second primary nut 664 and the second spindle 654, on the other hand. Here, in the meaning of the invention, the upper clamping rail 646 is a first clamping rail, whereas the lower clamping rail 648 is a second clamping rail.

[0086] Due to the fact that the threaded outer surfaces S652 and S654 extend continuously at least from the level of the primary nut 662, 664 to the level of the lower clamping rail 648, preferably on at least 90% of the length L6 of the spindles 652 and 654, the amplitude or range of displacement of the upper clamping rail 646 along the transverse axis B6 can be high. In particular, the upper clamping rail 646 can be brought into close vicinity to the upper crossbeam 626, or into close vicinity to the lower clamping rail 648, when necessary.

[0087] With this respect, the upper crossbeam 626 is located above the upper clamping rail 646 and above the lower clamping rail 648, with respect to the vertical axis Z6, in all positions of these clamping rails along the spindles 652, 654.

[0088] Advantageously, the lower clamping rail 648 is moved along the transverse axis B6 via the same kind of driving arrangement.

[0089] The references of parts of the clamping frame 6 interacting with the lower clamping rail 648, which are structurally or functionally similar to some parts interacting with the upper clamping rail 646, are increased by 1000, as compared to the references of the parts interacting with the upper clamping rail.

[0090] In particular, a first secondary nut 1662 and a second secondary nut 1664 are respectively mounted around the spindles 652 and 654 and have no possibility of movement in a direction parallel to the transverse axis B6 with regard to respectively a first secondary support 1672 and a second secondary support 1674, which are structurally and functionally similar to the first and second primary supports 672 and 674.

[0091] The nuts 662, 664, 1662 and 1664 are preferably identical.

[0092] The first and second secondary supports 1672 and 1674 are respectively similar to the first and second primary supports 672 and 674. The lower clamping rail 648 has no possibility of translational movement relative to the secondary nuts 1662, 1664 along an axis perpendicular to the main plane P6. All these supports include an armature 722, a skid 724, a bracket 726 and a box 728 similar to the ones of the first primary support 672.

[0093] A secondary driving arrangement 1800 is formed of two secondary actuators 1802 and 1804, respectively similar to the first and second primary actuators 802 and 804.

[0094] Figure 4 is taken across the actuator 1804 and shows some screws 1805 securing this actuator to the bracket 726 of the second secondary support 1674. Similar screws are used for the other actuators 802, 804 and 1802.

[0095] A secondary brake 1902 and 1904 is also associated to each secondary actuator 1802 or 1804. The first and second secondary brakes 1902 and 1904 belong to the secondary driving arrangement 1800.

[0096] Each secondary actuator 1802 and 1804 is configured to cause a relative rotation, around the first or second longitudinal axis B652 or B654, between a secondary nut 1662 or 1664 and the spindle 652 or 654 with the outer surface of which this secondary nut is in threaded engagement.

[0097] In other words, the secondary driving arrangement 1800 allows moving the lower clamping rail 648 with regard to the side posts 652, 644 along the direction parallel to the transverse axis B6, basically in the same way as the primary driving arrangement 800 for the upper clamping rail 646. In other words, a movement of each secondary nut 1662, 1664 with regard to the respective spindle 652, 654 causes a movement of the lower clamping rail 648 with regard to the respective spindle 652, 654 along the respective longitudinal axis B652, B654. In particular, as the secondary driving arrangement 1800 does not move the spindles 652, 654 relative to the primary nuts 662, 664, the position of the upper clamping rail 646 is not modified by the relative rotation between the first secondary nut 1662 and the first spindle 652, on the one hand, and between the second secondary nut 1664 and the second spindle 654, on the other hand.

[0098] The displacement of the upper clamping rail 646 parallel to the transverse axis B6 is obtained via the primary driving arrangement 800 independently of the displacement of the lower clamping rail 648 parallel to the transverse axis B6, which is obtained by the secondary driving arrangement 1800. In particular, depending if only one or two of the driving arrangements 800 and 1800 is / are supplied with electric power, the upper clamping rail 646 is moved parallel to the transverse axis B6 whereas the lower clamping rail 648 remains stationary, when only the primary driving arrangement 800 is supplied with electric power; the lower clamping rail 648 is moved parallel to the transverse axis B6 whereas the upper clamping rail 646 remains stationary, when only the primary driving arrangement 1800 is supplied with electric power; and both clamping rails 646 and 648 are moved parallel to the transvers axis B6, potentially with different speeds and different ranges of movement, when both driving arrangements 800 and 1800 are supplied with electric power.

[0099] For safety reasons, each brake 902, 904, 1902 or 1904 is adapted to stop rotation of the adjacent nut 662, 664, 1662 or 1664 with regard to its support 672, 674, 1672 or 1674 in case of power failure. Indeed, in case of power failure, the controller 66 does not supply energy to the coil that moves the second jaw 908 away from the first jaw 907 of each brake. In other words, all brakes 904, 1902 and 1904 work in the same way as the brake 902. This implies that any rotation of the nut 662, 664, 1662 or 1664 is prevented when the coils are not supplied with electric power, for instance in the event of a power failure or controller malfunction, which means that any displacement of the upper and lower clamping rails 644 and 646 along transverse axis B6 is also prevented.

[0100] Advantageously, a diameter of the threaded outer surface S652 or S654 is equal to about 25 mm and the pitch of the outer thread provided on this surface equals about 5 mm. A lead screw angle LSA of this thread is defined as α = arctan pitch / diameter × π = arctan 5 / 25 × π = 3.64 °

[0101] This lead screw angle α is small enough to guarantee a self-locking operation of the primary and secondary driving arrangements 800 and 1800 due to the geometry and thread friction between the spindles and the nuts. This lead screw angle α also reduces the torque to be exerted by a brake 902, 904, 1902 or 1904 to stop a nut along the first or second axis. In view of this construction, the brakes 902, 904, 1902 and 1904 can be more compact than usual brakes.

[0102] Each clamping rail 646 or 648 is mounted on the primary supports 672 and 674, or on the secondary supports 1672 and 1674, via cylindrical pins 686, 688, 1686 or 1688, partly housed in corresponding articulation recesses 696, 698, 1696 and 1698.

[0103] The articulation recesses 696 and 1696 are cylindrical with a circular cross section, respectively centered on the articulation axes A686 and A1686, A1686 being a central axis of the cylindrical pin 1686. These recesses are located, respectively in the upper clamping rail 646 and in the lower clamping rail 648, next to the left or first side post 642. The cylindrical pins 686 and 1686 cooperate with reduced radial clearance with the respective articulation recesses 696 and 1696. Articulation axes A686 and A1686 are thus stationary with regard to the upper clamping rail 646, respectively the lower clamping rail 648.

[0104] The articulation recesses 698 and 1698 are respectively located on the upper clamping rail 646 and on the lower clamping rail 648, close to the right or second side post 644. These articulation recesses 698 and 1698 are non-circular. Preferably the articulation recesses 698 and 1698 have an oblong shape. Their longitudinal dimension, parallel to the respective longitudinal axis A646, A648, is larger than their width, perpendicular to the respective longitudinal axis A646, A648 and to the lateral axis C6. The cylindrical pins 688 and 1688 cooperate with reduced clearance in a direction parallel to the transverse axis B6 with the respective articulation recesses 698 and 1698. This allows a relative movement of the cylindrical pins 688 and 1688, located at the right end of the clamping rails 646 and 648, with respect to these clamping rails. Thanks to this feature of the clamping frame 6, the longitudinal axis A646 of the upper clamping rail 646 may tilt, in particular relative to a horizontal direction represented by the main longitudinal axis A6 on figure 11 and relative to the transverse axis B6. Similarly, the longitudinal axis A648 of the lower clamping rail 648 may tilt, in particular relative to the horizontal direction and relative to the transverse axis B6. In such a case, axes A646 and A648 may be not parallel with respect to each other and not parallel to the main longitudinal axis A6. Such tilting movements occur in the main plane P6. The side posts 642, 644 and the clamping rails 646, 648 thus form a deformable quadrangle.

[0105] This allows moving the upper and lower clamping rails 646 and 648 respectively from the configuration represented in plain lines to the configuration represented in axis lines on figure 11. The tilting movement of the upper clamping rail 646 between its two positions represented on figure 11 is obtained exclusively via the primary driving arrangement 800 independently of the tilting movement of the lower clamping rail 648 between its two positions represented on figure 11, which is obtained exclusively via the secondary driving arrangement 1800. Such a tilting movement of one or two of the clamping rails 646 and 648 occurs in the main plane P6 and allows adjusting, along the main longitudinal axis A6, the yarn tension of any yarn layer held by the clamping frame 6 by locally reducing or increasing the spacing distance d6 between the clamping rails 646, 648.

[0106] The memory 166 of the controller 66 is configured to memorize several dedicated positions of the nuts 662, 664, 1662 and 1664, thus several dedicated positions of the clamping rails 646 and 648, along the spindle 652 or 654. A dedicated position can be the position of each clamping rail for layer preparation, as represented on figures 1 to 3 and 5, a position for drawing-in yarns into the weaving harness 8, as represented on figures 10 and 11, a position at the beginning of a tearing-down step, as represented on figure 12 or a position at the end of the tearing-down step, as represented on figure 13. The tearing-down is a step when the weaving harness 8 drawn-in with yarns is moved through the clamping frame 6 from the front side to the back side of the clamping frame 6, in order to bring this weaving harness 8 closer to the weaving beam B. Each dedicated position is defined with regard to the position of the respective nuts 662, 664 or 1662, 1664 with regard to the respective spindle 652, 654 along the transverse axis B6. The controller 66 can determine, depending on a present position of a nut 662, 664, 1662 or 1664 sensed by the sensor 912 and a set point position of this nut 662, 664, 1662 or 1664 corresponding to one of the dedicated positions, the rotation movement of this nut to be driven by the corresponding actuator 802, 804, 1802 or 1804 around the first longitudinal axis B652 or the second longitudinal axis B654, in order to safely and quickly bring the clamping rail 646 or 648 in the dedicated position.

[0107] Power supply and control of the motors 806 of the respective actuators 802, 804, 1802 and 1804 is provided through cables. Some of these cables extend from the controller 66 to the bottom of the left side post 642 and, from there, to each motor 806. Some other cables extend from the controller 66 to the right side of the clamping frame 6, at the level of the crossbeam 626 and, from there, into the right side post 644. Therefore, drawing-in of the warp yarns Y and tearing-down of the weaving harness 8 is not impacted by the cables. The cables are represented by chain-dotted lines 200 on figure 5 only. In order to accommodate the movements of the upper and lower clamping rails 646 and 648 parallel to the transverse axis B6, the cables 200 form deformable loops and partially extend into deformable cable guides 202, for instance made of articulated plastic parts. As visible on figure 5, the cable guides 202 and the cables 200 are located on the back side of the sub-frame 64.

[0108] According to an advantageous aspect of the invention, the upper crossbeam 626 is also equipped with connection means for connecting the clamping frame 6 to the drawing-in unit 4, for power and / or data transmission. These connection means are preferably carried by a drag chain 270 which is as long as the whole displacement of the drawing-in unit 4 with regard to the clamping frame 6 to follow this displacement and which is connected to the controller 66. These connection means are preferably releasable means so that the connection between the clamping frame 6 and the drawing-in unit 4 can be connected or disconnected.

[0109] When the drawing-in unit 4 is used for drawing-in and separating warp yarns Y from the yarn layer L1 of warp yarns stretched between the upper and lower clamping rails 646 and 648, as shown on figure 10, the controller 66 communicates with this unit in a bidirectional way, as shown by the connection line 206 on this figure. Preferably, this connection line 206 is provided at the level of the upper crossbeam 626 of the outer frame 62. Via this connection line L206, the controller 66 is connected to the unit controller 42, to the yarn separation device 44 and to the yarn separation detection device 46. In particular, bi-directional signals S206 transiting in the connection line 206 may include a signal received from the yarn separation detection device 46, which is taken into consideration by the controller 66 to control at least one of the actuators 802, 804, 1802, 1804 during drawing-in. The yarn separation can be improved in real time by taking into account the efficiency of the yarn separation assessed by the yarn separation detection device 46 and by modifying the tension within the layer L1 during drawing-in.

[0110] As each motor 806 can be piloted by the controller 66 individually, and thanks to the possibility of movement given by the cylindrical pins 686, 688, 1686 and 1688 and the articulation recesses 696, 698, 1696, 1698, the controller 66 can pilot the primary and secondary driving arrangements 800 and 1800 so that the upper and lower clamping rails 646 and 648 may be parallel to one another or not, within the main plane P6.

[0111] When the two clamping rails are non-parallel, during drawing-in, the controller 66 can progressively modify the tension of the warp yarns Y within the yarn layer L1 in an uneven way. For instance, the relative orientation of the upper and lower clamping rails can be chosen to increase the tension of the yarns close to the yarn separation device 44, in order to facilitate yarn separation and increase the rate of successful operation of the yarn separation device 44.

[0112] On the other hand, the two clamping rails 646 and 648 may also be spread out in a parallel configuration, in order to evenly increase the yarn layer tension within the whole yarn layer L1. They can also be brought closer together in a parallel configuration in order to decrease the yarn layer tension within the whole yarn layer L1.

[0113] According to an advantageous aspect of the invention, the sub-frame 64, thus the main plane P6, may tilt with regard to the outer frame 62 around a pivoting axis A8, which is parallel, or globally parallel, to the main longitudinal axis A6. In particular, the pivoting axis is coplanar with the main plane P6. This pivoting axis A8 is materialized by a pivoting pin 208, secured to the lower end of each side post 642 or 644 and rotatably mounted in a cylindrical recess of the adjacent vertical stand 622 or 624 of the outer frame 62. The pivoting axis A8 has a fixed position relative to the outer frame 62 and is located below the lowest position of the lower clamping rail 648 with regard to the spindles 652, 654. In other words, the pivoting axis A8 is shifted to the ground G with respect to an area of the main plane P6 defined between the two clamping rails 646 and 648. In other words, the pivoting axis A8 is situated between the ground G and the lower clamping rail 648.

[0114] Preferably, the pivoting pin 208 is located at the level of the lower mounting base 656 of each side post 642 or 644.

[0115] First and second sides posts 642, 644 are secured to the outer frame 62 along the main longitudinal axis A6. First and second sides posts 642, 644 have no possibility of relative movement in a direction parallel to the transverse axis B6.

[0116] A guiding pin 210 is attached to the upper base 658 of each side post 642 or 644 and is engaged into a curved slot 212 provided in the upper part of the adjacent vertical stand 622 or 624. Advantageously, each curved slot 212 has a circular arc shape centered on the pivoting axis A8. This allows guiding a tilting movement of the sub-frame 64 with regard to the outer frame 62 around the pivoting axis A8.

[0117] This tilting movement of the sub-frame 64 induces a corresponding tilting movement of the main plane P6, of the transverse axis B6, of the spindles 652 and 654, of the side posts 642 and 644, of the supports 672, 674, 1672 and 1674 and of the upper and lower clamping rails 646 and 648.

[0118] Tilting of the sub-frame 64 can be initiated by an operator via a manual tilting actuation device 240, also called an inclination device, which includes a hand lever 242 connected to a sprocket wheel 244 which cooperates with an elongated toothed hole 246 provided on a guide plate 248. The hand lever 242 is rotative in the outer frame 62. The guide plate 248 is movable relative the outer frame 62 along a vertical direction, due to a rotation of the hand lever 242, thus to a rotation of the sprocket wheel 244. A cam groove 250 of the guide plate 248 pushes an inclination pin 252, which cooperates with one of the side posts 642 or 644, in order to control the position of this side post around the pivoting axis A8. In the example of the figures, the inclination pin 252 lies against the left side post 642.

[0119] The synchronization between the right and left side posts 642 and 644 regarding tilting around the pivoting axis A8 is made by a cable pull device with metallic transmission cables 402 secured to the two upper mounting bases 658 and guided by pulleys 404 on both left and right sides of the sub-frame 64.

[0120] During drawing-in, when warp yarns Y are drawn in through the elements 82, 84 and 86 of the weaving harness 8, the inclination pin 252 is situated in a recess 253 of the cam groove 250 giving the pin 252 a degree of freedom around the pivoting axis A8 with regard to the outer frame 62 and the vertical axis Z6 so that the transverse axis B6 may be inclined of + / - 3° with regards to the vertical axis Z6 by rotation of the sub-frame 64 around the pivoting axis A8. On figure 10, reference 252' shows the position of the inclination pin when it is tilted by 3° to the back side. The sub-frame 64 is in contact with the drawing-in unit in a direction parallel to the lateral axis C6 and may itself adjust its inclination with regard to the vertical axis Z6, depending on the location of the drawing-in unit, in particular in case of an unevenness of the ground G of the drawing-in room, on the path of the drawing-in unit 4.

[0121] In a non-representative preferred embodiment of the invention, a camera is provided on the outer frame 62 and connected to the controller 66. This camera allows monitoring the position of the sub-frame 64 relative to the outer frame 62, that is the tilting angle of the sub-frame 64 around the pivoting axis A8. This camera also allows monitoring the presence of an operator within an internal volume delimited by the outer frame 62, in order to avoid collision between the movable clamping rails 646 and 648, on the one hand, and the operator, on the other hand, when the primary and / or secondary actuators 802, 804, 1802 and 1804 are actuated by the controller 66.

[0122] A drawing-in method according to the invention can be implemented with the clamping frame 6 and the drawing-in unit 4 and includes, in particular, the following steps consisting in: a) preparing the yarn layer L1 from the weaving beam B by clamping the warp yarns of layer L1 on the upper and lower clamping rails 646, 648 of the clamping frame 6, before the actual drawing-in step; b) drawing-in warp yarns Y from the yarn layer L1 into the weaving harness 8; and c) tearing-down the weaving harness 8 drawn-in with warp yarns .

[0123] The tearing-down step c) requires bringing the weaving harness 8 from the front side of the main plane P6 to the back side of the main plane P6, that is on the side of the weaving beam B along the lateral axis C6, after drawing-in.

[0124] For one of the above steps or for each step, the controller 66 uses at least a dedicated position stored in the memory 166 of the controller 66, for the upper and lower clamping rails 646 and 648. A dedicated position is a position to be reached by a given clamping rail at the beginning of a step, during a step or at the end of a step.

[0125] For the layer preparation of step a), represented on figures 1 to 9, the spindles 652 and 654 and the main plane P6 are vertical and the controller 66 can actuate the four actuators 802, 804, 1802 and 1804 to reach the dedicated positions of the upper and lower clamping rails 646 and 648 for layer preparation. The two motors 806 of the two primary actuators 802 and 804 are actuated synchronously and the two motors 806 of the secondary actuators 1802 and 1804 are actuated synchronously.

[0126] In what follows, a height is a position along the transverse axis B6 with regard to spindles 652 and 654. The height of the upper clamping rail 646, respectively of the lower clamping rail 648, depends on the position of the primary nuts 662 and 664, respectively secondary nuts 1662 and 1664, with regard to the spindles 652 and 654, along the transverse axis B6. H6-1 denotes the height of the upper clamping rail 646 in this layer preparation position. This height is measured between the central axis A686 of the cylindrical pin 686 and the pivoting axis A8. H8-1 denotes the height of the lower clamping rail 648 in this layer preparation position. It is measured between the central axis A1686 of the cylindrical pin 1686 and the pivoting axis A8. Heights H6-1 and H8-1 are measured parallel to the transverse axis B6.

[0127] ΔH68-1 denotes the difference between heights H6-1 and H8-1. It corresponds to a distance between respective cylindrical pins 686 and 1686 cooperating with the two clamping rails 646 and 648 or to a distance between respective cylindrical pins 688 and 1688 cooperating with the two clamping rails 646 and 648 since these clamping rails are horizontal. The height difference ΔH68-1 equals the spacing distance d6, taken at the longitudinal level of axes A686 and A1686, plus a distance d646 between the axis A686 and a lower edge of the upper clamping rail 646 plus the distance d648 between the axis A1686 and an upper edge of the lower clamping rail 648, the distance d646 and d648 being taken along the transverse axis B6.

[0128] More generally, one has the following relationship: Δ H68 = d6 + d646 + d648 where ΔH68 and d6 are taken at the same longitudinal level. Distances d646 and d648 have constant values for a given inclination of the upper clamping rail 646, respectively of the lower clamping rail 648 with regard to the horizontal direction, since distances d646 and d648 are fixed by the geometry of the upper and lower clamping rails 646, 648. The relationship of equation 2 prevails in all positions of the upper and lower clamping rails 646 and 648.

[0129] During the preparation step a), the operator pulls the yarns of the layer L1 out from the weaving beam B, below the lower clamping rail 648 from the back side of the clamping frame 6 to the front side of the clamping rails 646 and 648, in front of the lower clamping profile 676, then in front of the upper clamping profile 676.

[0130] Then, the clamping rods 678 are inserted into the clamping profiles 676, respectively in the lower clamping rails 648 and in the upper clamping rail 646, while the yarns Y are tensioned, which clamps the yarns Y of the yarn layer L1 within the clamping profiles 676.

[0131] When the yarn layer L1 is clamped by the clamping rails 646, 648, the yarn extension within the yarn layer L1 is globally parallel to the transverse axis B6 and the yarn layer L1 is parallel to the main plane P6.

[0132] For more ergonomics, each operator can configure and store its own dedicated clamping rail positions, corresponding to heights H6-1 and H8-1, depending upon his / her own height. A tall operator can set height H6-1 to a higher value than a short operator.

[0133] During this operation, from the positions corresponding to the heights H6-1 and H8-1, the height difference ΔH68-2, thus the spacing distance d6 between the two clamping rails 646 and 648, can be adjusted step by step by the operator which can give instructions to the controller 66 through the display screen 68, in order to get a correct tension within the yarn layer L1.

[0134] In this preparation step a), the spindles 652 and 654 extend globally vertically and the upper and lower clamping rails 646 and 648 extend parallel to each other and to the main longitudinal axis A6. Therefore, the spacing distance d6 taken at the longitudinal level of axes A686 and A1686 is equal to the spacing distance d6 taken at the longitudinal level of axes A688 and A1688.

[0135] One defines second heights H6-2 and H8-2, in the drawing-in position represented on figure 10, third heights H6-3 and H8-3, at the beginning of a tearing-down step represented on figure 12, and fourth heights H6-4 and H8-4, at the end of the tearing-down step represented on figure 13.

[0136] After the layer preparation step a), the controller 66 can actuate the four actuators 802, 804, 1802 and 1804 of the sub-frame 64 to reach some other dedicated positions represented by heights H6-2 and H8-2 on figure 10, for the drawing-in step b). The difference ΔH68-2 between these heights H6-2 and H8-2 is the same as the difference ΔH68-1 between the first heights H6-1 and H8-1 at the end of step a). In other words, the tension of the yarn layer is kept constant between the configuration represented on figure 2 and the configuration represented on figure 10. One has the following relationship: Δ H68 − 2 = Δ H68 − 1

[0137] The situation is the same for the spacing distance d6, which keeps the same value between these dedicated positions.

[0138] In the drawing-in configuration of figure 10, during step b), the upper clamping rail 646 is higher, with regards to the pivoting axis A8, than in the preparation configuration represented on figure 2. In other words, one has the following relationship: H6 − 2 > H6 − 1

[0139] Since the differences ΔH68-2 and ΔH68-1 are equal, one also as the following relationship: H8 − 2 > H8 − 1

[0140] Bringing the clamping rails 646 and 648 and the yarn layer L1 upward enables the plugging of the clamping frame 6 with the drawing-in unit 4, at the height required by the drawing-in unit 4.

[0141] Preferably, in order to protect the yarn layer L1 against over-tension of the warp yarns Y, the upper and lower clamping rails 646 and 648 are moved with the same speed along the transverse axis B6, from their first layer preparation positions, with heights H6-1 and H8-1, to their second drawing-in positions, with heights H6-2 and H8-2 respectively. This is obtained by driving all the nuts 662, 664, 1662 and 1664 at the same speed, simultaneously, via the primary and secondary driving arrangements 800 and 1800.

[0142] Step b), that is drawing-in of the yarns Y of the yarn layer L1 through the weaving harness elements 82, 84 and 86, can then start.

[0143] An information about the type or dimension of the yarns Y to be separated from the yarn layer L1 can be stored in the memory 166 as a part of a drawing-in pattern. Alternatively, the type or dimension of the yarns Y to be separated can be recognized by the camera 46 belonging to the yarn separation detection device.

[0144] During the drawing-in step b), depending for instance on the yarn separation result assessed by the yarn separation device 46 or depending on the type of the yarns Y to be separated, the controller 66 may adjust automatically the height difference ΔH68-2, thus the spacing distance d6, or the tilting of the clamping rails 646 and 648 with respect to the main longitudinal axis A6 as shown on figure 11, that is the evolution of the spacing distance d6 along this main longitudinal axis A6. This enables adjusting the tension of the whole yarn layer L1 along the length of the clamping frame 6, or to adjust only the tension of the warp yarns Y close to the yarn separation device 44.

[0145] Alternatively, this adjustment of the height difference ΔH68-2 and the evolution of spacing distance d6 along this main longitudinal axis A6 can be driven by the operator through the display screen 68 and the controller 66.

[0146] On figure 11, the heights corresponding to the positions of the upper and lower clamping rails 648 and 646 in the tilted configuration represented by axis lines are different on the left side and on the right side of the clamping frame 6. The heights H6-2L of the clamping rail 646 next to the left side post 642, at the longitudinal level of articulation axis A686, is higher than the height H6-2R of the same clamping rail next to the right side post 644, at the longitudinal level of articulation axis A688. On the other hand, the height H8-2R of the lower clamping rail 648 next to the right side post 644, at the longitudinal level of articulation axis A1688, is higher than the height H8-2L of the same clamping rail next to the left side post 642, at the longitudinal level of articulation axis A1686.

[0147] During drawing-in of the yarns Y of the yarn layer L1 through the weaving harness elements 82, 84 and 86, the drawing-in unit 4 moves with regard to the sub-frame 64 and to the outer frame 62 along the main longitudinal axis A6. The controller 66 may take into account the position of the drawing-in unit 4 along the main longitudinal axis A6 in order to automatically adjust the spacing distance d6 at the longitudinal level of the front most yarn Y of the yarn layer L1 to be separated.

[0148] During drawing-in of the yarns Y, the sub-frame 64 may have a tilted movement around the pivoting axis A8 toward the front of the clamping frame 6, in the direction of the rotation arrow R64 on figure 10. The sub-frame 64 may also be tilted in the reverse direction, toward the back side of the clamping frame 6, in a non-represented position. The amplitude of this tilting movement is + / - 3° between the positions respectively represented on figure 10.

[0149] During drawing-in of the yarns Y of the yarn layer L1 through the elements 82, 84 and 86 of the weaving harness 8, in case of unevenness of the ground G on which the drawing-in unit 4 is moving parallel to the main longitudinal axis A6, the controller 66 may adjust the position of the upper and lower clamping rails 646 and 648, that is the heights H6-2 and H8-2, depending on the position of the drawing-in unit 4, especially the position of the yarn separation device 44 parallel to the transverse axis B6. In such a case, the lower and upper clamping rails 646 and 648 are preferably moved synchronously in the same direction parallel to the transverse axis B6. This is obtained by synchronously moving the primary and secondary nuts 662, 664, 1662 and 1664, at the same speed, via the primary and secondary actuators 802, 804, 1802 and 1804.

[0150] The drawing-in step b) ends when all yarns Y of the yarn layer L1 have been separated and drawn-in the elements of the weaving harness 8.

[0151] In the tearing-down step c), after all warp yarns Y of the yarn layer L1 have been drawn-in through the weaving harness elements 82, 84 and 86, the sub-frame 64 may have a tilted movement around the pivoting axis A8 toward the back side of the clamping frame 6, in the direction of the rotation arrow R'64 on figure 12. This is obtained by moving the inclination pin 252 via the actuating device 240 and especially the cam groove 250 between the positions respectively represented on figures 10 and 12.

[0152] This tilting movement of the sub-frame 64 is guided by the displacement of the guiding pin 210 within the circular arc shape slot 212.

[0153] β denotes the tilt angle of the sub-frame 64 to the back side of the clamping frame, relative to the outer frame 62. The maximum value of the tilt angle β is defined by the span of the circular arc shape slot 212.

[0154] This allows reaching the configuration of figure 12 where the drawing-in unit 4 has been removed from the clamping frame 6 and an angle between the transverse axis B6 and the vertical axis Z6 equals the maximum value of the tilt angle, about 8°.

[0155] At the beginning of the tearing-down step c), the upper and lower clamping rails are first brought horizontal and parallel to each other. In other words, the heights H6-2L and H6-2R are made equal and the heights H8-2L and H8-2R are made equal if they were previously different. Consequently, the heights difference ΔH68-2L and ΔH68-2R are also made equal along the main longitudinal axis A6. In other words, after the upper and lower clamping rails have been brought horizontal, the heights H6-2L and H6-2R are equal and the heights H8-2L and H8-2R are equal.

[0156] Then, the lower clamping rail 648 and the upper clamping rail 646 are moved toward each other, while remaining horizontal, in order to reach a position close to each other. The configuration reached at the end of this movement is shown on figure 12. The height difference ΔH68-3 in this configuration is much smaller than the height difference ΔH68-1 in the configuration of figure 2. The height difference ΔH68-3 and the spacing distance d6 in this configuration are the smallest possible height difference and distance between the lower and upper clamping rails 646 and 648, as the primary supports are in abutment against the secondary supports along transverse axis B6.

[0157] Preferably, ΔH68-1 is at least 7 times bigger as ΔH68-3. One has the following relationship: Δ H68 − 1 ≥ Δ H68 − 3 × 7

[0158] Heights H6-3 and H8-3 are low enough so that the operator can advantageously install the carriage 10 on at least one of the clamping rails, for instance the lower clamping rail 648 as shown on the figures. Here again each operator can configure and store its own dedicated clamping rail positions, corresponding to the heights H6-3 and H8-3. The operator then introduces the carriage 10 into the group of dropwires 82 and into the group of heddles 84 in a direction going from the front side to the back side of the clamping frame 6.

[0159] An arm 12 of the carriage 10 is telescopic and movable along a direction D12 perpendicular to axes A6 and Z6, in particular parallel to the plane of figures 2, 10, 12 and 13. This direction D12 is perpendicular to the outer frame 62.

[0160] The arm 12 is located below the lower clamping rail 648 in the configuration of figure 12.

[0161] At the end of the tearing-down step c), as shown on figure 13, the upper and lower clamping rails 646 and 648 are moved upwardly. In other words, they are brought to a fourth position with their heights H6-4 and H8-4 respectively bigger than the corresponding heights H6-3 and H8-3 in the configuration of figure 12, at the beginning of the tearing-down step c). One has the following relationships: H6 − 4 > H6 − 3 H8 − 4 > H8 − 3

[0162] The distance ΔH68-4 between the two clamping rails 646 and 648 remains the same as the distance ΔH68-3 in the configuration of figure 12. One has the following relationship: Δ H68 − 4 = Δ H68 − 3

[0163] Between configuration of figure 12 and configuration of figure 13, the lower and upper clamping rails 646 and 648 are preferably moved synchronously in the same direction parallel to the transverse axis B6. Thus, the upwardly directed movement of the clamping rails 646 and 648 induces a similar upper movement of the carriage 10 and of the harness elements 82, 84 and 86 which brings the arm 12 higher than the weaving beam B. It is then possible to move the carriage 10 along the direction D12, between the left and right side posts 642 and 644, through a free volume located between the side posts 642 and 644, which is no more obstructed by the upper and lower clamping rails 646 and 648 and which extends down to the ground G. In other words, the weaving harness 8 supported by the carriage 10 can be lifted and transferred from the front side to the back side of the clamping frame 6, without interference with the outer frame 62 or with the sub-frame 64. From the position represented on figure 13, the weaving harness elements 82, 84 and 86 can be transferred to a non-represented warp beam truck, which also supports the weaving beam B, on the back side of the clamping frame 6. The carriage 10 can then be disconnected from the corresponding clamping rail, for instance the lower clamping rail 648.

[0164] Then, the warp beam truck is used to carry the weaving beam B and the drawn-in weaving harness 8 to a non-represented loom.

[0165] As can be deducted from the different configurations represented on the figures, for instance by comparing heights H6-4 and H6-3, respectively heights H8-1 and H8-4, a wide range of displacement of the clamping rails 646 and 648 along the transverse axis B6 is advantageous. In particular, height H6-4 is the biggest height reachable by the upper clamping rail 646 on the clamping frame 6 as the primary supports 672 and 674 abuts against the upper mounting bases 658. Height H8-1 is the smallest height reachable by the lower clamping rail 648 on the clamping frame 6 as the secondary supports 1672 and 1674 abuts against the lower mounting bases 656. Height H8-4 is the biggest height reachable by the lower clamping rail 648 on the clamping frame 6.

[0166] One considers a non-represented configuration, where the upper clamping rail 646 is in the horizontal position represented on figure 13, at height H6-4, and the lower clamping rail 648 is in the horizontal position represented on figure 2, at height H8-1. In this configuration, the height difference and the spacing distance d6 have maximum values, respectively ΔH68 max and d6 max . The relationship of equation 2 prevails.

[0167] Consider the case where the upper clamping rail 646 remains in position H6-4 and where the lower clamping rail 648 moves from a first position shown on figure 2, at height H8-1, to a second position shown on figure 13, at height H8-4. In other words, the lower clamping rail 648 starts from the first position, where it is spaced from the upper clamping rail 646 with the maximum value d6 max of the spacing distance d6, and moves relative to each spindle 652, 654 along the transverse axis B6 on a range equal to H8-4 - H8-1 to reach the second position H8-4. This range of movement of the lower clamping rail 648 is strictly more than half of the maximum value d6 max . For example, H8-4 - H8-1 is equal to 1600mm and the maximum value d6 max is equal to 1700mm. Preferably, the upper clamping rail 646 and the lower clamping rail 648 have the same maximal range of movement.

[0168] Advantageously, the maximum value d6 max of the spacing distance d6 is greater than 1000mm, preferably greater than 1500 mm.

[0169] The wide range of displacement of the clamping rails 646 and 648 is obtained thanks to the primary and secondary driving arrangements 800 and 1800. In particular, when the lower clamping rail 648 is at the smallest height H8-1, the range on which the upper clamping rail 646 is movable along the transverse axis B6 is strictly more than half of the maximum value d6 max of the spacing distance d6 between the two clamping rails 646, 648. Also, when the upper clamping rail 646 is at the highest position H6-4, the range on which the lower clamping rail 648 is movable along the transverse axis B6 is strictly more than half of the maximum value d6 max of the spacing distance d6 between the two clamping rails 646, 648. In other words, from the configuration where the positions H6-4, H8-1 of the upper and lower clamping rails 646, 648 along the transverse axis B6 with regard to the first and second spindles 652, 654 define the maximum value d6 max of the spacing distance d6, the upper clamping rail 646 is movable relative to each spindle 652, 654 along the transverse axis B6 to reduce the spacing distance d6 to strictly less than half of the maximum value d6 max of the spacing distance d6. Also, from the configuration where the positions H6-4, H8-1 of the upper and lower clamping rails 646, 648 along the transverse axis B6 with regard to the first and second spindles 652, 654 define the maximum value d6 max of the spacing distance d6, the lower clamping rail 648 is movable relative to each spindle 652, 654 along the transverse axis B6 to reduce the spacing distance d6 to a value strictly less than half of the maximum value d6 max of the spacing distance d6.

[0170] In the second and third embodiments represented on figures 14 to 16, elements identical or comparable to the ones of the first embodiment bear the same references. Hereafter, if a reference is shown on one of figures 14 to 16 without being mentioned in the description or mentioned in the description without shown on the figures, it corresponds to the element or part bearing the same element in the first embodiment. Hereafter, one describes mainly the differences between the second or third embodiment and the first embodiment.

[0171] In the non-represented configuration where, the upper clamping rail 646 is in the horizontal position represented on figure 13, at height H6-4, and the spacing distance d6 has its maximum value d6 max , the upper crossbeam 626 extends above the upper clamping rail 646.

[0172] In the second embodiment of figures 14 and 15, the primary driving arrangement 800 is located at the level of the lower clamping rail 648 and includes a first primary actuator 802 and a second primary actuator 804, working as the secondary actuators 1802 and 1804 of the first embodiment. The primary driving arrangement 800 also includes non-represented primary brakes, similar to primary brakes 902 and 904 in the first embodiment.

[0173] The secondary driving arrangement 1800 includes a single secondary actuator 1802.

[0174] Each actuator 802, 804 and 1802 is respectively mounted on a first primary support 672, on a second primary support 674 and on a first secondary support 1672.

[0175] As shown on figure 15, an output shaft 806A and a head 806B of an electric motor 806 of the secondary actuator 1802 drives a first pulley 808 via a first belt 807.

[0176] The first pulley 808 is synchronized with a second pulley 809 via a movement transfer belt 810. The second pulley 809 is supported by a second secondary support 1674. The first pulley 808 is secured with a secondary nut 1662 around and along first longitudinal axis B652 and the second pulley 809 is secured with a secondary nut 1664 around and along second longitudinal axis B654.

[0177] In this case, the single actuator 1802, in particular the single motor 806 of this actuator 1802, drives a rotation of the two secondary nuts 1662 and 1664 respectively in threaded engagement on the spindles 652 and 654 located close to the two side posts 642 and 644 of the sub-frame 64.

[0178] In this second embodiment, the outer threaded surfaces S652 and S654 of the spindles 652 and 654 extend at least between the primary nuts 662 and 664 and the upper clamping rail 646, in all positions of the clamping rails 646 and 648, preferably on at least 90% of the length of the spindles 652 and 654, this length being defined as in the first embodiment. Thus, the amplitude or range of movement of the clamping rails 646 and 648 is close to the total length of the spindles.

[0179] In this second embodiment, the position of the upper clamping rail 648 is not modified by the relative rotation between the first primary nut 662 and the first spindle 652, on the one hand, and between the second primary nut 664 and the second spindle 654, on the other hand, this relative rotation taking place at the level of the lower clamping rail 648. Here, in the meaning of the invention, the lower clamping rail 648 is a first clamping rail, whereas the upper clamping rail 646 is a second clamping rail. Advantageously, in addition, the position of the lower clamping rail 648 is not modified by the relative rotation between the first secondary nut 1662 and the first spindle 652, on the one hand, and between the second secondary nut 1664 and the second spindle 654, on the other hand.

[0180] In this second embodiment, the longitudinal axis A646 of the upper clamping frame 646 is parallel to the main longitudinal axis A6, i.e. parallel to a horizontal direction. The longitudinal axis A648 of the lower or first clamping rail 648 may tilt, in a main plane defined as main plane P6 for the first embodiment, in particular relative to a horizontal direction. The longitudinal axis A646 of the upper or second clamping rail 646 cannot tilt in the main plane P6. In this case, preferably, the upper clamping frame 646 always remains parallel to the main longitudinal axis A6, since it is not possible to vary a distance comparable to distance H6-2L with respect to a distance comparable to distance H6-2R in the first embodiment because the two secondary nuts 1662 and 1664 are always driven together and synchronously.

[0181] In the third embodiment of figure 16, the primary driving arrangement 800 is mounted at the level of the upper clamping rail 646, as in the first embodiment, and includes two primary actuators 802 or equivalent, having each an electric motor 806. The electric motor 806 of the first primary actuator 802 is capable of driving a primary nut 662 in rotation around a first longitudinal axis B652 of a spindle 652. The electric motor of the non-represented second primary actuator is capable of driving a non-represented second primary nut in rotation around a second longitudinal axis of a non-represented second spindle.

[0182] No secondary driving arrangement is mounted on the lower clamping rail 648. Instead, a secondary driving arrangement 1800 is formed of two secondary actuators, 1802 and equivalent, and associated non-represented secondary brakes. Each secondary actuator is mounted on a sole 628 of a left or right vertical stand 622 or equivalent of the outer frame 62 of the clamping frame 6 of the third embodiment. Figure 16 shows a first secondary actuator 1802, located next to the left vertical stand 622. A second non-represented secondary actuator is located next to the right vertical stand.

[0183] The first secondary actuator 1802 includes an electrical motor 806 with an output shaft 806A equipped with a splined head 806B which drives a pulley 807. The pulley 807 drives a wheel 1812 fast in rotation with the spindle 652. The wheel 1812 drives the spindle 652 in rotation around its first longitudinal axis B652 with regard to the outer frame 62.

[0184] A secondary nut 1662 is secured to a secondary support 1672, both in translation and in rotation around the first longitudinal axis B652. A rotation of the spindle 652 around its longitudinal axis B652 drives the secondary nut 1662 and the support 1672, thus the lower clamping rail 648, along this axis.

[0185] Here, the first longitudinal axis B652 is an axis of rotation for the first primary nut 662 driven by the primary actuator 802 and an axis of rotation for the first spindle 652 driven by the secondary actuator 1802.

[0186] The same arrangement is provided for the second secondary actuator, near the right side post.

[0187] In this case, tilting of the longitudinal axis of the upper clamping rail, in a main plane defined as main plane P6 for the first embodiment, can be obtained, as explained for the first embodiment. Tilting of the longitudinal axis of the lower clamping rail 648 in the main plane P6 with respect to a main longitudinal axis, as represented on figure 11 for the first embodiment, can be obtained by piloting differently the two secondary actuators 1802 and equivalent.

[0188] In this third embodiment, the outer threaded surface S652 of the spindle 652 extends at least between the primary nut 662 and the lower clamping rail 648, in all positions of the clamping rails 646 and 648, preferably on at least 90% of the length of the spindle defined as in the first embodiment. The same applies for the outer treaded surface of the second non-represented spindle. Thus, the amplitude or range of movement of the clamping rails 646 and 648 is close to the total length of the spindles.

[0189] In this third embodiment, the position of the lower clamping rail 648 is not modified by the relative rotation between the first primary nut 662 and the first spindle 652, on the one hand, and between the second primary nut and the second spindle, on the other hand. Here, in the meaning of the invention, the upper clamping rail 646 is a first clamping rail, whereas the lower clamping rail 648 is a second clamping rail. In this third embodiment, the position of the upper clamping rail 646 is modified by the relative rotation between the first secondary nut 1662 and the first spindle 652, on the one hand, and between the second secondary nut and the second spindle, on the other hand, and shall be compensated by the primary driving arrangement 800 to bring the upper clamping rail 646 at the correct position along transverse axis B6.

[0190] In all embodiments and in any position of the lower clamping rail 648 relative to the spindles 652 and 654, a volume delimited by the two side posts 642 and 644 and the lower clamping rail 648, below the lower clamping rail 648, is free from crossbeams and from cables. This facilitates movements of the operator, displacements of the drawing-in unit 4 and tearing-down of the weaving harness 8.

[0191] The invention is not limited to the embodiments represented on the figures.

[0192] In a non-represented variant of the invention, each clamping rail 646, 648 is configured to clamp the yarns Y of the yarn layer L1 within the corresponding clamping profile 676 thanks to a comb, according to the teachings of US2942324A.

[0193] In another non-represented variant of the invention, one clamping rail is fixedly mounted with regard to the side posts 642 and 644 of the sub-frame 64, without possibility of relative movement with regard to the spindles 652 and 654 parallel to the transverse axis B6. In such a case, the fixed clamping rail is preferably the upper clamping rail 646 of the sub-frame 64 and the first clamping rail, in the meaning of the invention, is the lower clamping rail 648. The primary driving arrangement can be either the driving arrangement 800, 1800 of the first embodiment or the driving arrangement 1800 of the third embodiment.

[0194] In another non-represented variant of the invention, in case the longitudinal axis of the first clamping rail cannot tilt in the main plane P6, the two primary supports may have a single piece construction and / or may be formed by the first clamping rail itself.

[0195] According to another non-represented variant, the cylindrical pin 686 or 688 is mounted and secured to the clamping rail and the circular-cylindrical articulation recess 1686 or 1688 is provided on the primary support 672.

[0196] In another non-represented variant of the invention, the secondary driving arrangement comprises only one actuator driving the rotation of a single secondary nut with regard to the corresponding spindle in order to adjust the orientation of the longitudinal axis of the second clamping rail with regard to the main longitudinal axis A6. The height position of the second clamping rail at the level of the other spindle is not adjustable.

[0197] In another non-represented variant of the invention, the sub-frame 64 is arranged to clamp two yarn layers of warp yarns side by side, with two clamping rails. Each clamping rail is thus equipped with two clamping profiles, as disclosed in EP4033021 A1. Considering one of the two clamping rails, a first clamping profile is secured with the clamping rail along the transverse axis whereas the second clamping profile is also secured with this clamping rail along the transverse axis or is movable relative to the first clamping profile along the transverse axis by an additional layer tensioning device which is manually actuated by the operator, preferably during the layer preparation of step a), and which doesn't change the position of this clamping rail relative to the spindles along the transverse axis. At least one of the clamping profiles is movable relative the clamping rail along the respective longitudinal axis of the clamping rail that supports the clamping profile. Adjustment of the positions of the two yarn layers along main longitudinal axis A6 may be made with a motor secured with the clamping rail and controlled by the controller 66. This allows adjusting an offset between the two yarn layers, which allows alternative yarn separation of yarn from the two yarn layers by a single yarn separation device 44. Dedicated positions can be memorized for each yarn layer and the clamping frame 6 may adjust the positions of at least one of the clamping rails each time a new layer is selected for yarn separation during step b).

[0198] According to another non-represented variant, the outer frame 62 is equipped with wheels and the clamping frame 6 can be moved to, and away from the drawing-in position in which step b) takes place. This allows performing layer preparation in a first preparation room, prior to moving the clamping frame 6 to a second drawing-in room where the drawing-in unit 4 is stored. When the drawing-in unit is mobile within the drawing-in room and relative to the clamping frame 6 during step b), the wheels of the outer frame 62 are braked during the preparation step, in the first room, and during the drawing-in and tearing-down steps, in the second room. When the drawing-in unit is fixed within the drawing-in room and the clamping frame 6 is mobile within the drawing-in room and relative to the drawing-in unit 4 during step b), the wheels of the outer frame 62 convey the clamping frame with regard to the drawing-in unit. A plug allows a removable connection of the clamping frame 6 in the preparation room and / or in the drawing-in room, for power and control signals.

[0199] According to another non-represented variant, the sub-frame 64 may include two pairs of upper and lower clamping rails, that is two upper clamping rails and two lower clamping rails. Each pair of clamping rails is configured for clamping one yarn layer. In such a case, preferably, a first pair of clamping rails is associated to a first pair of first and second spindles, whereas a second pair of clamping rails is associated to a second pair of first and second spindles. The spacing distance is thus to be considered between the upper and lower clamping rails of the same pair of clamping rails. The clamping frame 6 has thus four parallel spindles comparable to spindles 652 and 654, two main planes comparable to main plane P6, parallel to each other, and five to eight motors comparable to motors 806, for moving the clamping rails along the respective spindles, all being preferably controlled by the controller 66.

[0200] According to another non-represented variant of the invention, the inclination of the sub-frame 64 with regard to the outer frame 62 is motorized. Preferably, a sensing device may detect a tilting angle of the main plane P6 with regard to the vertical axis Z6 and provide the corresponding information to the controller 66.

[0201] According to another non-represented variant, instead of a resolver, the position sensor 912 may be an optical sensor, such as a camera watching the positions of a nut or the clamping rail with regard to the spindles parallel to the transverse axis B6. Alternatively, this sensor can be an inductive sensor.

[0202] According to another non-represented variant, the sub-frame 64 or the drawing-in unit 4 is equipped with a sensor for detecting the yarn tension within the yarn layer L1, at least in the vicinity of the yarn separation device 44. In a variant, brushless DC motors are used in the actuators 802, 804, 1802 and 1804 and, advantageously, the yarn tension is directly measured through the motors 806.

[0203] According to another non-represented variant of the invention, the sub-frame 64 or the drawing-in unit 4 is equipped with a sensor for detecting a relative position of the drawing-in unit 4 and the outer frame 62 parallel to the transverse axis B6 in order to adjust, when necessary, the position of the clamping rails 646 and 648 parallel to the transverse axis B6 during relative movement of the drawing-in unit 4 relative to the clamping frame 6, along the main longitudinal axis A6.

[0204] According to another non-represented variant of the invention, the drawing-in machine 2 comprises a mobile drawing-in unit 4 and two clamping frames 6 of the type mentioned here above, spaced relative to one another along the main longitudinal axis A6. The mobile drawing-in unit 4 interacts alternatively with one clamping frame 6 or with the other. In such a case, for safety reasons, the actuators of the two sub-frames 64 of the two clamping frames 6 are all connected to the same controller 66. In such a case, a power or data connection, in particular an emergency signal connection, is provided between the two clamping frames 6, advantageously at the level of the upper crossbeams 626 of their respective outer frames 62. In such a case, a sensor is advantageously provided for detecting the longitudinal position of the drawing-in unit 4, with regard to each sub-frame 64, along the main longitudinal axis A6.

[0205] The embodiments and variants of the invention mentioned here above may be combined, in any technically feasible way, in order to generate news embodiments of the invention, in the framework of the appended set of claims.

Claims

1. A clamping frame (6) for clamping warp yarns (Y) of at least one yarn layer (L1), the clamping frame comprising at least: - first and second side posts (642, 644); - an upper clamping rail (646) and a lower clamping rail (648) configured for clamping the warp yarns of the at least one yarn layer (L1), the first and second side posts mechanically connecting the upper and lower clamping rails together, the upper and lower clamping rails extending between the first and second side posts and being spaced along a transverse axis (B6), characterized in that: - the first side post (642) comprises a first spindle (652) with a first threaded outer surface (S652) centered on a first longitudinal axis (B652); - the second side post (644) comprises a second spindle (654) with a second threaded outer surface (S654) centered on a second longitudinal axis (B654); - the first longitudinal axis (B652) and the second longitudinal axis (B654) are parallel to the transverse axis (B6), have a fixed position relative to one another and together define a main plane (P6); - the clamping frame comprises two primary nuts (662, 664), each primary nut being in threaded engagement with one of the first threaded outer surface (S652) and the second threaded outer surface (S654) respectively ; - at least a first clamping rail (646; 648; 646), among the upper and lower clamping rails, is mechanically connected to the two primary nuts (662, 664), so that a movement of each primary nut with regard to the respective spindle in a direction parallel to the transverse axis (B6) causes a movement of the first clamping rail (646; 648; 646) with regard to the respective spindle in a direction parallel to the transverse axis (B6) and the first clamping rail (646; 648; 646) has no possibility of translational movement relative to the primary nuts (662, 664) along an axis perpendicular to the main plane (P6); - the clamping frame (6) comprises a primary driving arrangement (800) including two primary actuators (802, 804), each primary actuator being configured to cause a relative rotation, around the respective first or the second longitudinal axis (B652, B654), between the respective primary nut (662, 664) and the respective spindle (652, 654), - the position of the second clamping rail (648; 646; 648), among the upper and lower clamping rails, along the transverse axis (B6) relative to the first and second spindles (652, 654) is not modified by the relative rotation between each primary nut (662, 664) and the respective spindle (652, 654); - from a configuration where the positions (H6-4, H8-1) of the upper and lower clamping rails (646, 648) along the transverse axis (B6) with regard to the first and second spindles (652, 654) define a maximum value of a spacing distance (d6) between the upper clamping rail (646) and the lower clamping rail (648) along the transverse axis (B6), the first clamping rail (646, 648 ; 646) is movable relative to each spindle (652, 654) along the transverse axis (B6) to reduce the spacing distance (d6) to a value strictly less than half of the maximum value of the spacing distance (d6); - the clamping frame (6) comprises a controller (66) for controlling the two primary actuators (802, 804).

2. The clamping frame of claim 1, wherein : - each primary nut (662, 664) is mounted on a primary support (672, 674) without possibility of translational movement between the primary nut and the primary support, in a direction parallel to the transverse axis (B6) and in all directions perpendicular to the transverse axis (B6); - each primary support (672, 674) cooperates with a guide member (666) of the adjacent side post (642, 644), the guide member (666) extending parallel to the transverse axis (B6) and blocking the primary support (672, 674) in rotation around the respective longitudinal axis (B652, B654); - each longitudinal end of the first clamping rail (646; 648; 646) is articulated on a primary support (672, 674) so that a longitudinal axis (A646) of the first clamping rail (646; 648; 646) has a possibility of tilting movement with regard to the transverse axis (B6).

3. The clamping frame of claim 2, wherein : - an articulation axis (A686) of one longitudinal end of the first clamping rail (646; 648; 646) with regard to the respective primary support (672) is perpendicular to the main plane (P6) and stationary relative to the first clamping rail (646 ; 648 ; 646) and to the respective primary support (672) ; - the other longitudinal end of the first clamping rail (646 ; 648; 646) comprises an articulation recess (698) which cooperates, in a direction parallel to the transverse axis (B6), with a cylindrical pin (688) of the respective primary support (674), the cylindrical pin (688) being centered on an articulation axis (A688) perpendicular to the main plane (P6) and the articulation recess (698) having an oblong shape with a larger dimension in a direction parallel to the longitudinal axis (A646) of the first clamping rail (646; 648; 646).

4. The clamping frame of any preceding claim, wherein - each primary nut (661, 662) is mechanically connected to the first clamping rail (646; 648; 646) with a possibility of relative rotation around the respective first longitudinal axis (B652) or second longitudinal axis (B654); - each primary actuator (802, 804) is secured to the respective primary nut (661, 662), at least along the transverse axis (B6); and - each primary actuator (802, 804) is configured to rotate the respective primary nut (662, 664) with regard to the first clamping rail (646; 648; 646) and to the respective spindle (652, 654) around the respective longitudinal axis (B652, B654).

5. The clamping frame of any preceding claim, wherein the primary driving arrangement (800) includes at least one brake (902,904) configured to selectively oppose a relative rotation between a primary nut (662, 664) and the respective spindle (652, 654).

6. The clamping frame of any preceding claim, wherein the first and the second spindles (652, 654) are secured with mounting bases (656, 658) of the side posts (642, 644) without possibility of rotation around the respective first longitudinal axis (B652) or second longitudinal axis (B654).

7. The clamping frame of any preceding claim, wherein - the second clamping rail (648; 646; 648) is mechanically connected to two secondary nuts (1662, 1664), each secondary nut being in threaded engagement with one of the first threaded outer surface (S652) and the second threaded outer surface (S654) respectively ; - the second clamping rail (648; 646; 648) is mechanically connected to the two secondary nuts (1662, 1664), so that a movement of the secondary nut with regard to the respective spindle in a direction parallel to the transverse axis (B6) causes a movement of the second clamping rail (648; 646; 648) with regard to the respective spindle in a direction parallel to the transverse axis (B6) and the second clamping rail (648; 646; 648) has no possibility of translational movement relative to the secondary nuts (1662, 1664) along an axis perpendicular to the main plane (P6); - the clamping frame comprises a secondary driving arrangement (1800) which includes at least one secondary actuator (802) configured to cause at least a relative rotation, around the respective first or the second longitudinal axis (B652, B654), between a secondary nut (1662, 1664) and the respective spindle; - the first threaded outer surface (S652) and the second threaded outer surface (S654) extend continuously from the respective primary nut (662; 664) to the respective secondary nut (1662; 1664); and - the controller (66) is configured to control the at least one secondary actuator (802).

8. The clamping frame of any preceding claim, also comprising an outer frame (62) with two vertical stands (622, 624) configured to stand on a ground (G), wherein the first and second side posts (642, 644) and the upper and lower clamping rails (646, 648) are mounted on the outer frame (62), between the two vertical stands, with a possibility of tilting movement (R64, R'64) of the main plane (P6) relative to the two vertical stands (622, 624), around a pivoting axis (A8), the pivoting axis (A8) being perpendicular to the transverse axis (B6),fixed in position with respect to the outer frame (62) and situated between the ground (G) and the lower clamping rail (648) along the transverse axis (B6).

9. The clamping frame of any preceding claim, wherein - the clamping frame (6) comprises an upper crossbeam (626), which extends above the upper clamping rail (646) when the upper clamping rail (646) is in the position (H6-4) with regard to the first and second spindles (652, 654) along the transverse axis (B6) defining the maximum value of the spacing distance (d6) between the upper clamping rail (646) and the lower clamping rail (648); and - the upper crossbeam (626) is equipped with connection means for connection to a drawing-in unit (4) and / or to another clamping frame (6).

10. The clamping frame of any preceding claim, wherein it includes at least one sensor (912) configured to detect a relative position between a nut (662, 664, 1662, 1664) and the respective spindle (652, 654), the sensor (912) being connected to the controller (66).

11. The clamping frame of any preceding claim, wherein it includes a carriage (10) removably mounted on the first clamping rail (646, 648) and configured for supporting a weaving harness (8) so that the weaving harness (8) is co-moved with the first clamping rail (646; 648; 646) relative to the first and second spindles (652, 654) along the transverse axis (B6) by the primary driving arrangement (800).

12. A drawing-in machine (2) for drawing-in warp yarns (Y) from at least one yarn layer (L1) into a weaving harness (8), characterized in that it includes - at least one clamping frame (6) according to any preceding claim; - a drawing-in unit (4) equipped at least with ∘ a yarn separation device (44) configured to separate a warp yarn from the at least one yarn layer (L1) clamped in the clamping frame (6); ∘ a threading device configured to draw-in each separated warp yarn through the weaving harness (8).

13. A drawing-in method for drawing-in warp yarns (Y) from at least one yarn layer (L1) into a weaving harness (8), using - a clamping frame (6) according to one of claims 1 to 11 and - a drawing-in unit (4) equipped at least with ∘ a yarn separation device (44) configured to separate a warp yarn from at least one yarn layer (L1) clamped in the clamping frame (6); and ∘ a threading device configured to draw-in each separated warp yarn through the weaving harness (8), wherein the method includes at least the following successive steps consisting in: a) preparing the at least one yarn layer (L1) from a weaving beam (B) by clamping the warp yarns on the upper and lower clamping rails (646, 648) of the clamping frame (6) ; b) drawing-in warp yarns (Y) from the at least one yarn layer (L1) into the weaving harness (8); and c) tearing-down the weaving harness (8) drawn-in with warp yarns, from a front side to a back side of the main plane (P6) and wherein the controller (66) of the clamping frame (6) controls the at least two primary actuators (802, 804) in order to place the first clamping rail (646; 648; 646) at a first position along the transverse axis (B6) during one of the steps a), b) or c) and at a second position along the transverse axis (B6) during another step among steps a), b) or c), the first and second positions being different positions and being each defined with regard to the position of each primary nut (662, 664) with regard to the respective spindle (652, 654) along the transverse axis (B6).

14. The method according to claim 13, wherein - the controller (66) of the clamping frame (6) includes a memory (166); - several different dedicated positions of the first clamping rail (646; 648; 646) are stored in the memory of the controller, each dedicated position being defined with regard to the position of each primary nut with regard to the respective spindle (652, 654) along the transverse axis (B6), - the controller (66) controls the at least the two primary actuators (802, 804) in order to place the first clamping rail (646; 648; 646) in one of the dedicated positions.

15. The method according to one of claims 13 and 14, wherein - the drawing-in unit (4) is equipped with a yarn separation detection device (46) connected to the controller (66) and configured to detect a result of the yarn separation performed by the yarn separation device (44); and - during step b), at least one of the primary actuators (802, 804) is controlled by the controller (66), depending on a signal (S206) received by the controller (66) from the yarn separation detection device (46), to adjust the position of the first clamping rail (646; 648; 646) with regard to the first and second spindles (652, 654) along the transverse axis (B6).

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