Dobby device for controlling the motions of at least one weaving frame of a weaving machine, and a weaving machine provided with such a dobby device

Abstract

The invention relates to an electronic dobby device (100) for controlling the motions of at least one weaving frame of a weaving machine, wherein the at least one weaving frame is connected to two rotors (1,2) by means of a rod and lever system, wherein each rotor (1,2) is mounted on a rotor shaft (5,6) by means of an eccentric bearing, and wherein each rotor (1,2) is individually selected to be connected or not to the rotor shaft (5,6) by means of one or several selection elements in accordance with the weaving pattern to be woven, in order to move between two possible positions that can be taken up by the rotor (1,2) with respect to the rotor shaft when the rotor (1,2) is disconnected from the rotor shaft (5,6) by the selection elements, wherein the said two rotors (1,2) each are eccentrically journalled on a different rotor shaft (5,6) and both rotor shafts (5,6) are rotating continuously and for rotating over a complete rotation require the same period of time, and in that the said weaving frame can take up at least three different positions during each machine cycle to weave the required weaving pattern. On the other hand, the invention relates to a weaving machine provided with such a dobby device (100).

Description

Furthermore, some of these embodiments are discussed in the figures herewith attached, wherein reference is made to these figures by means of reference numbers, wherein:

FIG. 1 represents a perspective view of a dobby device according to the invention;

FIGS. 2 and 3 represent schematic views of a dobby device according to the invention with a lever system to realize four positions with two rotors;

FIGS. 4 and 5 represent a schematic view of a dobby device according to the invention with an adjustable lever system for switching between a device with three and four positions.

As represented in FIG. 1, in an electronic dobby device (100) according to the invention, for controlling the motions of at least one weaving frame of a weaving machine, the at least one weaving frame is connected to two rotors (1,2) through a rod and lever system, wherein each rotor (1,2) is journalled eccentrically (3) on a rotor shaft (5,6). Each rotor (1,2) is individually selected by means of one or several selection elements (not represented in the figures) in accordance with the weaving pattern to be woven, in order to be connected or not to the rotor shaft (5,6), thus to move between two possible positions which may be taken up by the rotor (1,2) with respect to the rotor shaft (5,6) when the rotor (1,2) is disconnected from the rotor shaft (5,6) by means of the selection elements. The said two rotors (1,2) each are eccentrically journalled on a different rotor shaft (5,6) and both rotor shafts (5,6) rotate continuously and need the same period of time for rotating through a complete rotation. In other words, both rotor shafts (5,6) perform a same number of rotations within a same period of time. Furthermore, the said weaving frame can take up at least three different positions during each machine cycle, generated by the at least three different positions (I, II, III, IV) taken up by the intermediate rods and levers, in order to weave the required weaving pattern.

The two rotor shafts (5,6) may therewith rotate in the same direction or in a different (opposite) direction. The modulation on the rotating motion of each rotor shaft (5,6) that brings the rotor shaft (5,6) to a standstill for a short moment in order to enable a possible coupling of the rotors (1,2) with their respective rotor shaft (5,6), may be the same for both rotor shafts (5,6) but may also be chosen to be different.

Both rotor shafts (5,6) may be connected mechanically to the main drive shaft of the weaving machine. The rotor shafts (5,6) may also be driven by a stepping motor or a servomotor (7). Both rotor shafts (5,6) may be driven by one and the same stepping motor or servomotor (7) with an intermediate driving mechanism with an input shaft which is connected to the output shaft of the stepping motor or servomotor or to two output shafts that each are connected to one of the two rotor shafts (5,6). However, both rotor shafts (5,6) may also be driven separately by a stepping motor or a servomotor (7), by which a greater flexibility is offered towards adjustment. When driving the rotor shafts (5,6) by means of one or several stepping motors or servomotors (7), the selection elements that take care that the rotors (1,2) are connected or not to the respective rotor shafts (5,6) may be carried out as actuators that realize the connection or disconnection between rotor (1,2) and rotor shaft (5,6).

Furthermore a control device (not represented in the figures) is provided that coordinates the synchronization of the drive of the said rotor shafts (5,6) and the selection elements with the drive of the main drive shaft of the weaving machine.

As represented in FIG. 2, the extremities of each one of the rotors (1,2) may be connected to a first lever (8,9) which hinges round a shaft (10) with a fixed center axis and the two first levers (8,9) connected to a common second lever (11). The first levers (8,9) may therewith be connected to the common second lever (11) by means of one or more connecting rods (12).

Preferably, the rotors (8,9) are installed on their respective rotor shafts (5,6) at a pitch being equal to the pitch at which the weaving frames are installed one behind the other in the weaving machine. Preferably, the thickness of the rotors (8,9) substantially corresponds to the thickness of a weaving frame.

According to the state-of-the-art, the pitch at which the weaving frames are installed one behind the other in velvet weaving machines amounts for instance 18 mm. The currently available rotors for dobby devices for flat weaving machines have a thickness enabling their installation next to each other on the rotor shaft at a pitch of 12 mm.

In the state-of-the-art, a three-position electronic dobby device for velvet, is realized by installing two rotors per weaving frame, as used in flat weaving machines, next to each other on the same shaft (the total pitch across 2 rotors being 24 mm). The weaving frames are installed at a pitch of 18 mm in order to restrict the overall dimension of the package of weaving frames as much as possible (in order to limit the lift to be realized by the weaving frames to form the shed). Each pair of rotors have a width of 2×12 mm, and are connected to first levers at the same pitch of 2×12 mm, that are connected together with one second lever which each time is carried out with 6 mm more axial displacement of his two ends, in order to realize the transition of the position of the rotors at 2×12 mm to the position of the weaving frames at 18 mm in order to maintain the packages of weaving frames compact. Because of this displacement the force generated by the tension of the warp yarns exerts a couple on the second lever with axially displaces end through weaving frames and rod system, that causes a radial load as well as an axial load on the shaft of the lever around which the second levers hinge. For this reason, the said lever shaft has to be axially journalled.

Now, according to the invention, by dividing the rotors (1,2) over two different rotor shafts (5,6), the rotors (1,2) may be installed on the rotor shaft (5,6) at the same pitch as the pitch of the weaving frames, i.e. 18 mm. Because of it, the rotors (1,2) can be made stronger having a thickness of 17 mm, for instance, instead of 12 mm. Thus, a three- or four-position electronic dobby device (100) may be realized that is able to manage much higher loads and wherein it is no longer required to make use of second levers (11) with axially displaced ends, such that the load of the warp yarn on the axis onto which the first levers (8,9) are hinging remains limited to an almost radial load and an axial bearing of the second levers (11) on their shaft can be avoided. The use of wider rotors (1,2) may also offer the advantage that standard bearings can be used to journal the rotors (1,2) eccentrically on the rotor shaft (5,6). It is usual to use specifically developed bearings or integrated bearings to journal the eccentric disk (3,4) and the rotor (1,2) when constructing a dobby device, because normally for the loads and speeds that are used in weaving machines for producing flat fabrics, the dimensions of the rotor (1,2) as to thickness are comparatively small with respect to the diameter of the rotor shaft (5,6), Bearings in this ratio of width with respect to the diameter are not commercially available and therefore also often are used as special bearings or integrated bearings. By using wider rotors (1,2) on shorter rotor shafts (5,6), a ratio of bearing width to bearing diameter may be obtained which indeed is commercially available, by which the price of these bearings when produced in smaller quantities yet remains interesting and notably lower than in case special bearings should herefore have to be manufactured.

The embodiment as represented in FIG. 2 and as described above has indeed the disadvantage that it contains many pivoting points, levers and connecting rods. This is disadvantageous both for the cost prize as well as the cost of maintenance of the dobby device (100). This problem is solved by connecting the two rotors (1,2) directly by means of a second lever (11) which in turn is connected to the weaving frame by means of a lever and rod system known, as is represented in FIG. 3. One of the rotors (1,2), in FIG. 3 this is the first rotor (1), still is connected to a fixed point (14) through a hinged arm (13), for instance to the frame of the dobby device (100). As already mentioned above, this fixed point (14) however may be situated also in some other part of the weaving machine. The two positions of the second rotor (2) result in four positions of the second lever (11). This embodiment has the advantage that the number of pivoting points and the number of components is strongly reduced.

In the embodiment as represented in the FIGS. 4 and 5, both rotors (1,2) are connected to a same first lever (8) which is connected to a second lever (11) by means of a connecting rod (12). One extremity of the second lever (11) is connected hingedly on a shaft with a fixed center in the dobby device or in the weaving machine, and its other extremity is connected to a lever and rod system realizing the connection with a weaving frame. This embodiment has a number of components and pivoting points situated between the numbers of the embodiments as represented in the FIGS. 2 and 3. By exerting the coupling of the connecting rod (12) to the first lever (8) and to the second lever (11) in an adjustable manner, the positions taken up by the free extremity of the second lever (11) may be adjusted with respect to one another. This for instance allows to position the backing warp yarns in a face-to-face weaving machine asymmetrically, such that the shed forming of the backing warp yarns of the lower fabric is different from shed forming of the backing warp yarns of the upper fabric which, under certain circumstances, may be important from a weaving technological viewpoint, for instance, for guiding the weft insertion means in the lower fabric on the backing warp yarns when moving through the shed.

In the embodiment as represented in FIG. 4, the second lever (11) may impose three positions (I, II, III) on the weaving frame, whereas in the embodiment as represented in FIG. 5, the second lever (4) may impose 4 positions (I, II, II, IV) on the weaving frame. The embodiments as represented in the FIGS. 4 and 5 are different from one another only because of the fact that the connecting rod (12) provided to be adjustable in the dobby device, is taking up another position.

In the embodiment as represented in the FIGS. 2 to 5, the common second lever (11) moves in accordance with a superposition of motions generated by the first rotor (1) on the first rotor shaft (5) and generated by the second rotor (2) on the second rotor shaft (6). The two possible positions of the first rotor (1) with the two positions of the second rotor (2) thus result in four positions (I, II, II, IV) of the second lever (11). The rod system that is constituted by the first (8,9) and second levers (11) and the possible connecting rods (12) may be chosen such that two of the four positions (I, II, II, IV) coincide, in order to be able to position the weaving frames into three positions.

The rotors (1,2) that are mounted on two different rotor shafts (5,6) and that are connected or not to a common second lever (11) by means of intermediate levers and connecting rods, preferably are situated in a same plane perpendicular to their respective rotor shafts (5,6).

The first levers (8,9) or the second lever (11) which are connected to a rotor (1,2) may be connected single-sidedly to the rotors (1,2). This means that the first lever (8,9) or the second lever (11) extend on one side of the rotor(s) (1,2) there where they are connected to each other. In this case, the levers (8,9,11) are of a simple construction, however, this embodiment is generating a couple of forces on the rotor (1,2) because of the eccentric transmission of the load of the warp yarns on the rotor (1,2) through these first (8,9) or second (11) levers. In order to avoid this, the levers (8,9,11) are preferably connected to the rotor (1,2), by means of a double-sided connection. This means that either the extremity of the rotor (1,2) is extending around the lever (8,9,11), for instance, through a radial recess at the extremity of the rotor (1,2) or that the lever (8,9,11) extends around the rotor (1,2), for instance, through a radial recess at the extremity of the lever (8,9,11). The levers (8,9,11) are in turn connected to the rod system driving the weaving frames.

Claims

1. Electronic dobby device (100) for controlling the motions of at least one weaving frame of a weaving machine, wherein the at least one weaving frame is connected to two rotors (1,2) by means of a rod and lever system, wherein each rotor (1,2) is mounted on a rotor shaft (5,6) by means of an eccentric bearing, and wherein each rotor (1,2) is individually selected to be connected or not to the rotor shaft (5,6) by means of one or several selection elements in accordance with the weaving pattern to be woven, in order to move between two possible positions which may be taken up by the rotor (1,2) with respect to the rotor shaft when the rotor (1,2) is disconnected from the rotor shaft (5,6) by the selection elements, wherein the said two rotors (1,2) each are eccentrically journalled on a different rotor shaft (5,6) and both rotor shafts (5,6) are rotating continuously and for rotating over a complete rotation require the same period of time, and in that the said weaving frame can take up at least three different positions during each machine cycle to weave the required weaving pattern.

2. Electronic dobby device according to claim 1, wherein both said rotor shafts (5,6) are rotating in the same direction.

3. Electronic dobby device according to claim 1, wherein both said rotor shafts (5,6) are rotating in an opposite direction.

4. Electronic dobby device according to claim 1, wherein in order to attain a standstill to couple a rotor (1,2) to its respective rotor shaft (5,6), the rotating motion of both rotor shafts (5,6) is modulated, wherein this modulation is the same for both rotor shafts (5,6).

5. Electronic dobby device according to claim 1, wherein in order to attain a standstill to connect a rotor (1,2) to its respective rotor shaft (5,6), the rotating motion of both rotor shafts (5,6) is modulated, this modulation being different for both rotor shafts (5,6).

6. Electronic dobby device according to claim 1, wherein the weaving machine is provided with a main drive shaft, wherein both rotor shafts (5,6) are mechanically connected to this main driving shaft.

7. Electronic dobby device according to claim 1, wherein both rotor shafts (5,6) are driven by one and the same stepping motor or servomotor (7) with an intermediate driving mechanism with an input shaft that is connected to the output shaft of the stepping motor or servomotor and with two output shafts each of them connected to one of the two rotor shafts (5,6).

8. Electronic dobby device according to claim 1, wherein both rotor shafts (5,6) each are separately driven by a stepping motor or a servomotor (7).

9. Electronic dobby device according to claim 7, wherein a control is provided for coordinating the synchronization of the drive of the said rotor shafts (5,6) with the main drive shaft of the weaving machine.

10. Electronic dobby device according to claim 7, wherein the selection elements that select whether the rotors (1,2) are connected or not to the rotor shafts (5,6) are carried out as actuators realizing the connection and disconnection between the rotor and rotor shaft.

11. Electronic dobby device according to claim 1, wherein the extremities of each of both rotors (1,2) are connected to a first lever (8,9) that hinges around a shaft (10) with a fixed center axis and wherein the two first levers (8,9) are connected to a common second lever (11).

12. Electronic dobby device according to claim 11, wherein the first levers (8,9) are connected to the common second lever (11) by means of one or several rods (12).

13. Electronic dobby device according to claim 11, wherein the first levers (8,9) are directly connected to the common second lever (11), wherein one of the rotors (1,2) are connected to a fixed point (14) through a hinged arm (13).

14. Electronic dobby device according to claim 11, wherein the second lever (11) moves in accordance with a superposition of motions that are generated by the first rotor (1) on the first rotor shaft (5) and of motions generated by the second rotor (2) on the second rotor shaft (6) enabling the second lever (11) to reach four positions (I, II, II, IV).

15. Electronic dobby device according to claim 11, wherein the rod system formed by the said first and second levers (8,9,11) and the possible connecting rods (12) is provided in such a way that two of the four positions which may be taken up by the second lever coincide, in order to enable the weaving frames to be brought into three positions (I, II, III).

16. Electronic dobby device according to claim 1, wherein both rotors (1,2) are connected to one and the same first lever (8 or 9) which is connected to a second lever (11) by means of a connecting rod (12).

17. Electronic dobby device according to claim 16, wherein the second lever (11) at one extremity hingedly is connected to a shaft (10) with a fixed center, and in that the other extremity is connected to a lever and rod system realizing the connection with a weaving frame.

18. Electronic dobby device according to claim 16, wherein the couplings of the connecting rod to the first and second lever respectively (8,9,11) are adjustable, through which the positions taken up by the free extremity of the second lever (11) are adjusted with respect to one another.

19. Electronic dobby device according to claim 1, wherein both rotors (1,2) are installed in a same plane perpendicular to their respective rotor shafts (5,6).

20. Electronic dobby device according to claim 11, wherein the first levers (8,9) or the second lever (11) are connected to their respective rotors by means of a single-sided connection.

21. Electronic dobby device according to claim 11, wherein the first levers (8,9) or the second lever (11) are connected to their respective rotors by means of a double-sided connection.

22. Electronic dobby device according to claim 1, wherein the rotors (1,2) are installed next to each other on their respective rotor shafts (5,6) at a pitch which is equal to the pitch at which the weaving frames are installed in the weaving machine one after the other.

23. Electronic dobby device according to claim 1, wherein the rotors (1,2) have a thickness substantially corresponding to the thickness of a weaving frame.

24. Weaving machine provided with an electronic dobby device according to claim 1.