CN113825866B

CN113825866B - Shed forming device

Info

Publication number: CN113825866B
Application number: CN202080036347.5A
Authority: CN
Inventors: B.范德朱格特
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-06-20
Filing date: 2020-06-19
Publication date: 2024-04-02
Anticipated expiration: 2040-06-19
Also published as: ES2970174T3; US20220316103A1; EP3987094A1; WO2020255066A1; WO2020255066A9; BE1027384B1; CN113825866A; EP3987094B1; BE1027384A1; EP3987094C0

Abstract

The invention relates to a shed forming device comprising a jacquard device (2), in which jacquard device (2) heddles (16, 17) are connected to return elements (18, 19) for exerting a downward force on the heddles (16, 17), wherein for each heddle (16, 17) one yarn tensioning element (8) is provided for changing the yarn tension in at least one associated warp yarn (11, 12), and a control or handling unit is provided for handling or controlling the yarn tension in at least one associated warp yarn (11, 12) for each heddle (16, 17) respectively, for bringing the total downward force on the heddles (16, 17) to a specific value, or for changing the total downward force according to a specific curve.

Description

Shed forming device

Technical Field

The invention relates to a shed forming device comprising a jacquard device having a plurality of heddles for positioning at least one associated warp yarn, wherein each heddle is connected to a return element for exerting a downward force on the heddle.

Background

In successive weft insertion cycles on a loom, one or more weft yarns are inserted into a shed formed between warp yarns. In order to weave in accordance with a predetermined weave pattern, the individual warp yarns must be positioned correctly in each shed with respect to one or more weft insertion heights. Jacquard machines are used to position a plurality of warp yarns differently in each shed.

The positioning is performed with heddles connected to respective hooks by means of ropes, wherein each heddle has one heddle eyelet. The hook may be moved up and down by means of a blade that moves up and down and selected by a selection means to hold it in one of a plurality of possible positions or not. Each warp yarn passes through a heddle eye of the heddle such that each distinct position of the heddle corresponds to a distinct position of the warp yarn.

In order for the shed formation to take place correctly and for the downward movement of the hooks to be facilitated, each heddle is connected to a return spring for exerting a downward force on the heddle. At the lowest position of the heddle, the amount of tension of the spring is at its minimum value, so that the downward force exerted by the return spring on the heddle is minimal. The return spring is chosen such that this minimum force is still just enough to allow the hook connected to the heddle to engage correctly on the chosen edge of the blade.

In the lowest position of the heddle, the warp yarn passing through the heddle eyelet also exerts an upward force on the heddle. This is caused by yarn tension in these warp yarns. Thus, in this lowermost position, the return spring must exert a downward force on the heddle that is greater than said upward force, and the resultant downward force must also be just sufficient to allow the selection hook to engage on the selection edge of the blade. Therefore, this minimum downward tension cannot be too small.

As the heddle is moved to a higher position by the blade, the downward spring force increases proportionally with the upward movement of the heddle, eventually reaching a value that is much greater than desired. As a result, the average tension on the warp yarn is much higher than necessary. Higher tension means more wear on the machine parts, more general, more frequent damage to the warp yarn itself, and more energy consumption of the machine.

Disclosure of Invention

The object of the present invention is to remedy these drawbacks.

This object is achieved by providing a shed forming device having the features described in the first paragraph of the present description, wherein, according to the invention, the shed forming device comprises, for each heddle, a yarn tensioning element for varying the yarn tension in at least one associated warp yarn, the shed forming device further comprising a control or operating unit which cooperates with the respective yarn tensioning element for operating or controlling the yarn tension in at least one associated warp yarn, respectively, for each heddle such that the total downward force on the heddle reaches a specific value or varies according to a specific curve.

The shed-forming device according to the invention can be used to manipulate or control the tension curve in the warp yarn such that the combined action of yarn tension and spring always exerts a downward force on the heddle that is large enough to achieve good shed formation but reaches a maximum value that is lower than when using existing shed-forming devices. This means less wear, less yarn damage and lower energy consumption.

In addition, less powerful pullback elements may be selected. At the lowest heald position, the yarn tension can still be manipulated or controlled to a lower value than when using existing shed forming devices. Thus, the pullback element must provide a lower force to achieve the necessary minimum downward force.

The steering or control system may also be designed to allow the total downward force during the weaving process to take on a number of predetermined continuous values. In some cases, certain machine parameters (e.g., machine position or machine speed) or data related to the weave pattern or weave structure may also be provided to the steering or control system for consideration in determining a target value for the total downward force.

The curve may be selected, for example, from a set of two or more reference curves or two or more reference sequences (e.g., tables or files) having at least one yarn tension reference value. In this way, during weaving, an appropriate reference curve or sequence of references can be selected, for example, based on machine parameters and/or weaving pattern data.

In a preferred embodiment, each yarn tensioning element comprises a roller driven by a motor and in contact with at least one warp yarn and intended to rotate in one or the other direction of rotation to move said warp yarn in a direction opposite to the feeding direction of the warp yarn, or to move the warp yarn or to promote the movement of the warp yarn, so as to move in the same direction as the feeding direction of the warp yarn with the movement of the warp yarn (i.e. the moving warp yarn) to increase or decrease the yarn tension in said warp yarn, respectively.

The pullback element may be any type of element designed to exert a force, such as other elements that provide a force at least in part by a pneumatic drive element and/or gravity. Preferably these elements are elements which provide the downward force at least partially, preferably fully or mainly using elastically deformable elements. In a most preferred embodiment, the pullback element is a spring.

The yarn tensioning device preferably comprises a measuring device for measuring yarn tension or a measured variable of yarn tension in at least one warp yarn or in a plurality of (at least two) warp yarns constituting a group. Preferably, the control unit also has means to repeatedly or continuously compare the measured yarn tension or a yarn tension measurement variable with a reference value and to generate a control signal when there is a difference between the measured yarn tension or variable and the reference value, which control signal is used to drive the yarn tensioning element (for example by adjusting the current of the control motor or by adjusting the motor torque) such that the difference between the measured value and the reference value is reduced.

The control unit preferably comprises an adjustor for generating a control signal for driving the yarn tensioning element (e.g. by adjusting the current of the control motor or by adjusting the motor torque) when a specific target value of the yarn tension is set, so that the target value is approached or reached. The regulator is preferably a "feed forward control" type regulator.

In one particular embodiment of the steering or control unit, machine parameters (e.g., machine position or machine speed, or data related to weave pattern or weave structure) may also be obtained, and one or more of these parameters may be used for control or steering.

If one or more yarn tension influencing conditions are different for different groupings of warp yarns, in the loom different reference yarn tension profiles can be determined for these groupings and can be individually adjusted according to the conditions that have changed during weaving and in different groupings as required during weaving. This allows the average value of the yarn tension to be kept somewhat lower while the maximum value of the yarn tension is not as high.

The yarn tensioning device comprises, for example, detection means for detecting the status of one or more yarn tension influencing situations during weaving, and/or storage means and/or data processing means to predefine the time or stage of the yarn tension influencing situation occurring during weaving according to the weaving pattern and/or according to the recommended warp path between the yarn store and the fabric.

In this loom, the method according to the invention preferably uses a control system with a "bi-directional forced feed forward function". This means that as the movement of the yarn changes, the yarn tensioning unit may intervene to facilitate such a change, so as to react more quickly.

Further specific features of the shed-forming device are specified in the claims.

The invention will now be further explained with reference to the following more detailed description of one possible embodiment of a jacquard machine according to the invention. It is emphasized that the described apparatus and methods are merely examples of the general principles of the invention and should not be taken as limiting the scope of protection or application of the invention as defined by the claims.

Drawings

In this detailed description, reference is made to the accompanying drawings, wherein:

FIG. 1 is a schematic side view of the structure of a loom and creel with an associated yarn tensioning device;

fig. 2 is a graph of the following for a pile-forming warp yarn in a number of successive weft insertion cycles during weaving in the prior art:

development of the position of the heddle eyes (in mm),

development of an upward or downward component (in newtons) of the force acting on the heddle due to yarn tension in the pile warp yarns,

development of the downward spring force (in newtons) of the return spring acting on the heddle of the pile warp yarn, and

development of the sum of the downward spring force on the heddle (in newtons) and the upward or downward component of the force acting on the heddle due to the yarn tension in the pile warp yarn (in newtons);

FIG. 3 is a graph of the following for a pile-forming warp yarn in a plurality of successive weft insertion cycles during weaving with controlled or manipulated yarn tension in accordance with the present invention:

development of the position of the heddle eyes (in mm),

development of the downward spring force (in newtons) of the return spring acting on the heddle of the pile warp yarn,

development of the sum of the downward spring force (in newtons) on the heddle and the upward or downward component (in newtons) of the force acting on the heddle due to the yarn tension in the pile warp yarn, and

-an average value of the sum of said forces.

Detailed Description

In a particular installation, a weaving machine (1) which cooperates with a jacquard device (2) is mounted beside a creel (3), and a creel (4) with four rolls (40) - (43), each containing a yarn store, is arranged in the space between the weaving machine (1) and the creel (3).

The yarn tensioning device (6) is mounted in the space between the creel (3) and the weaving machine (1) and consists of a yarn tensioning module (20), which yarn tensioning module (20) extends in a horizontal direction parallel to a vertical plane containing the front side (30 a) of a plurality of adjacent creel units (30). The yarn tensioning module (20) comprises two plate-like carriers (21), (22) with flat outer surfaces, which run symmetrically towards each other with respect to the horizontal plane in the direction of the weaving machine (1), wherein they are brought together and joined together at an angle. The yarn tensioning module (20) has a V-shaped profile as seen in a vertical section. Each carrier (21), (22) carries a plurality of rows of yarn tensioning elements (8) arranged in close proximity to each other. For clarity, only three yarn tensioning elements (8) are shown for each carrier (21), (22). For each warp yarn guided from the corresponding bobbin in the creel (3) to the loom (1), a conduit (10) is provided to guide the warp yarn without tension to the corresponding yarn tensioning element (8).

The warp threads are moved further from the thread tensioning element (8) to a grid (100) which has the same width as the thread tensioning module (20) but a smaller height. The warp threads (11, 12) run from the grid (100) to the weaving machine (1), where they pass through the heald eyes of the respective heald threads (16, 17), which heald threads are symbolically shown here with vertical threads representing circular widening of the heald eyes. The respective return springs (18), (19) exert a downward force on each heddle (16), (17).

According to the prior art, warp threads are supplied in a stretched state from a creel (3) to a first grid (X). Fig. 1 shows a prior art situation, in which a straight line (S1) runs from the uppermost row of bobbins in the creel (3) first through the grid (X) of the prior art device and then onto the grid (100); the straight line (S2) passes from the lowest row of bobbins in the creel (3) through the grid (X) of the existing device and then onto the grid (100). The mesh (X) is not part of the device of the invention, which is added to the figures for clarity only for comparison with the prior art to present the effects of the invention.

The lines (S1), (S2) show the magnitude of the angle (with respect to the horizontal) at which the warp yarn is brought to the grid (X) and then onto the grid (100) in the prior art, and thus the angle taken by the supplied warp yarn subsequently.

During weaving, the heddles (16, 17) move up and down to correctly position the warp yarns (11, 12) according to a predetermined weaving pattern. The return springs (18), (19) in their lowermost position provide the necessary downward force to properly form the shed, but must also overcome the upward force due to yarn tension.

If the heald is moved to a higher position to form the shed, the downward spring force increases proportionally with the upward movement of the heald, eventually reaching a value that is much greater than necessary.

In fig. 2, the line G1 in the drawing shows the development of the downward force of the springs (18), (19) acting on the heddle (16), (17) of the pile warp yarn (on the vertical axis on the left in newtons) for a number of successive weft insertion cycles (the state of the main shaft of the loom being shown in degrees on the horizontal axis); line G2 in the figure shows the development of alternating upward and downward components of the forces (in newtons) acting on the heddles (16), (17) due to yarn tension in the pile warp yarns. The latter force is hereinafter simply referred to as "yarn tension".

For clarity, in fig. 2 and 3 the force (spring force or yarn tension) is marked as negative, which means that the force pulls the heddle upwards. This is clear, for example, because the yarn tension is negative in the pattern area where the heddle is in its lowest position. It is evident that the force exerted on the heddle by the yarn tension has an upward component that pulls the heddle upwards.

Line G4 in the figure shows the position of the heald eye (on the right vertical axis in mm).

Line G3 in the figure shows the development of the sum of the spring force and the yarn tension. Here, two peaks (P1), (P2) of this total force can be seen. Line G3 in the figure shows the forces to which the different machine parts are subjected. It should be noted that the graphs in fig. 2 and 3 show the forces resulting from the movement of a single pile warp yarn, whereas on a typical double layer fabric loom, there may be more than 32000 pile warp yarns, for example.

Fig. 3 shows the development of spring forces and yarn tension on the heddle of the pile warp yarn when the yarn tension is controlled or manipulated to obtain a lower peak value and an average of the sum of the lower spring force and the yarn tension.

Due to this manipulation or control, springs with a lower spring constant and a lower spring preload (below 0.15 newton), which is the downward spring force when the heddle is in the lowest position, can also be used. The pretension may be lower because the pile warp yarn applies less upward yarn tension due to manipulation or control of yarn tension.

In fig. 3, the same marks (G1), (G2), (G3), and (G4) as in fig. 2 are used for the lines in the drawing, and they have the same meaning: namely the development of the downward spring force (G1), the development of the yarn tension (G2), the development of the sum of spring force and yarn tension (G3) and the position of the heald wire (G4). The vertical axis on the left gives the force values (in newtons) and the vertical axis on the right gives the heald position values (in millimeters). The horizontal axis represents the state of the loom main shaft in degrees.

The line (G5) (dashed line) in the figure gives the average value of the sum of the spring force and the yarn tension.

It is clear from line (G3) in the figure that the peak has disappeared (compared to peaks P1 and P2 in fig. 2) for the total force on the heddle. Furthermore, the average value of this total force is low. In a design without a steering or control system (fig. 2), the calculated average value of the total force is 2.91 newtons, whereas in a design with a control system the total force is 2.72 newtons (line G5 in fig. 3).

These effects mean a lower load on the machine, where it is also not forgotten that the values in the figure show the forces due to the movement of a single pile warp yarn, whereas on a typical double-layer fabric loom there may be more than 32000 pile warp yarns, for example.

The advantageous aspects of the invention are not limited to pile warp yarns, but are also applicable to another type of warp yarn positioned by a jacquard device, or to single-sided looms.

Claims

1. Shed forming device comprising a jacquard device (2) having a plurality of heddles (16, 17) for positioning at least one associated warp yarn (11, 12), wherein each heddle is connected to a return element (18, 19) for exerting a downward force on the heddle (16, 17), characterized in that for each heddle (16, 17) the shed forming device comprises a yarn tensioning element (8) for varying the yarn tension in the at least one associated warp yarn (11, 12), the shed forming device comprises a control or handling unit which cooperates with the respective yarn tensioning element (8) and which handles or controls the yarn tension in the at least one associated warp yarn (11, 12) for each heddle (16, 17) by determining a target value of the yarn tension or yarns, respectively, such that the total downward force on the heddle (16, 17) reaches a specific value or varies according to a specific curve.

2. Shed forming device according to claim 1, characterized in that each yarn tensioning element (8) comprises a roller which is driven by a motor and which is in contact with at least one warp yarn and which is intended to rotate in one or the other direction of rotation for moving the warp yarn (11, 12) in a direction opposite to the feeding direction of the warp yarn, or for moving the warp yarn (11, 12) in the same direction as the feeding direction of the warp yarn or for moving or promoting the movement of the warp yarn for increasing or decreasing the yarn tension in the warp yarn, respectively.

3. Shed-forming device according to claim 1 or 2, characterized in that the parameters of the jacquard device (2) or the weaving machine (1) with which the jacquard device cooperates, or the data or parameters relating to the weaving pattern, are provided to the control or operating unit for consideration in determining the target value of the total downward force.

4. Shed-forming device according to claim 1 or 2, characterized in that it comprises a memory unit in which two or more reference yarn tension curves and/or two or more reference sequences of at least one yarn tension reference value are stored, and that the control or manipulation unit is arranged to select a reference curve or reference sequence from the set for use as a manipulated or controlled target value or series of target values.

5. Shed forming device according to claim 1 or 2, wherein the return element is a spring (18, 19).