Pile-formation method and pile-formation device in cloth-shifting-type pile loom

Abstract

 In a cloth-shifting-type pile loom (1) that drives a take-up-side terry motion member (18) and a let-off-side terry motion member (7) individually with designated first and second electrical actuators (41, 42), respectively, the cloth-shifting-type pile loom (1) drives the first electrical actuator (41) and the second electrical actuator (42) in an asynchronous manner. A driving condition corresponding to each of a plurality of weaving conditions is set for at least one of the electrical actuators (41, 42) such that a magnitude of a difference in driving amounts between the electrical actuators (41, 42) varies depending on weaving operations performed under different weaving conditions. The driving condition of one of or each of the electrical actuators (41, 42) is changed when a weaving condition is switched to another weaving condition during a weaving operation.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present invention relates to a pile-formation method and a pile-formation device in a cloth-shifting-type pile loom.

2. Description of the Related Art

[0002] Japanese Unexamined Patent Application Publication No. 2-47334 discloses an example of a cloth-shifting-type pile loom. According to Fig. 11 and the specification in Japanese Unexamined Patent Application Publication No. 2-47334, a guide roller 4 defining a let-off-side terry motion member for guiding ground warp yarns and a breast beam 6 defining a take-up-side terry motion member for guiding woven cloth are respectively driven by servo-motors 37, 36. It is also disclosed that a control operation of the guide roller 4 includes shedding compensation. The term "shedding compensation" refers to an operation for compensating for a change (an increase) in warp tension caused by a shedding motion.

[0003] Another example of a cloth-shifting-type pile loom is disclosed in Japanese Unexamined Patent Application Publication No. 11-172552. In Japanese Unexamined Patent Application Publication No. 11-172552, a ground-warp tension roller 7 defining a let-off-side terry motion member and a take-up-side terry motion member are controlled in an asynchronous fashion. It is disclosed that this structure allows for compensation for a change in warp tension caused by a shedding motion.

[0004] Although the phrase "shedding compensation is performed" is written in the specification of Japanese Unexamined Patent Application Publication No. 2-47334, the specification does not have any detailed description concerning the phrase. On the other hand, according to the embodiment that describes the structure in detail in Japanese Unexamined Patent Application Publication No. 11-172552, the terry motion members are driven by a cam mechanism, which is driven by a main shaft. Consequently, according to this structure, the difference in driving modes (i.e. driving distances, driving timings, and driving speeds) between the terry motion members is always constant for the driving operations of the terry motion members.

[0005] In this case, however, if a weaving operation is performed while a weaving condition, such as the shedding pattern and the weft density, is switched to another weaving condition during a continuous run of the loom, the difference in driving modes between the terry motion members cannot be suitably adjusted between the weaving operation before the switching of the weaving conditions and the weaving operation after the switching of the weaving conditions. As a result, if the difference in driving modes is set based on one of the weaving conditions, the weaving operation performed under the other weaving condition may easily induce weaving problems, such as broken warp yarns.

SUMMARY OF THE INVENTION

[0006] Accordingly, it is an object of the present invention to provide a method and a device that prevents weaving problems, such as broken warp yarns, even when weaving conditions are switched in the process of a weaving operation performed by a cloth-shifting-type pile loom in which a let-off-side terry motion member (ground-warp tension roller) and a take-up-side terry motion member (breast beam / cloth guide roller) are individually driven by designated actuators.

[0007] The present invention provides a pile-formation method in a cloth-shifting-type pile loom which drives a take-up-side terry motion member and a let-off-side terry motion member individually with designated first and second electrical actuators, respectively. The pile-formation method includes the steps of driving the second electrical actuator for the let-off-side terry motion member and the first electrical actuator for the take-up-side terry motion member in an asynchronous manner, wherein a driving condition corresponding to each of a plurality of weaving conditions is set for at least one of the electrical actuators such that a magnitude of a difference in driving amounts between the electrical actuators varies depending on weaving operations performed under different weaving conditions; and changing the driving condition of one of or each of the electrical actuators when a weaving condition is switched to another weaving condition during a weaving operation.

[0008] The designated electrical actuators are generally defined by servo-motors, but are not limited to servo-motors. Alternatively, the electrical actuators may be any type of actuators as long as they are capable of electrically controlling the driving distances. Furthermore, instead of performing the asynchronous driving operations of the second electrical actuator for the let-off-side terry motion member and the first electrical actuator for the take-up-side terry motion member based on different driving distances, the asynchronous driving operations may alternatively be performed based on different driving timings (drive-start timings and drive-end timings) or on different speed patterns (speed patterns when shifting between a forward-limit position and a backward-limit position). Consequently, the term "driving condition" for each electrical actuator includes the driving distance, the driving timing, and the driving speed.

[0009] On the other hand, the term "weaving condition" includes a plurality of weaving-related parameters. The "weaving-related parameters" include, for example, a shedding pattern, a rotational speed of the loom, a weft density, a weft type, a warp tension, a shifting distance of cloth (pile length), and the number of pile picks. The term "a plurality of weaving conditions" refers to two or more weaving conditions, such that at least one of the weaving-related parameters is different between the weaving conditions.

[0010] Furthermore, the present invention also provides a pile-formation device in a cloth-shifting-type pile loom. The pile-formation device includes a first electrical actuator for driving a take-up-side terry motion member; a second electrical actuator for driving a let-off-side terry motion member; a driving-condition setting device for setting driving conditions for the first electrical actuator and the second electrical actuator; and drive-control means for driving the electrical actuators based on the driving conditions set in the driving-condition setting device. The cloth-shifting-type pile loom drives the first electrical actuator and the second electrical actuator in an asynchronous manner based on different driving conditions so that the take-up-side terry motion member and the let-off-side terry motion member are driven in different modes. The driving-condition setting device sets a plurality of driving conditions for at least one of the electrical actuators.

[0011] Furthermore, each weaving condition may include a rotational speed of the loom, a weft density, a weft type, a shifting distance of cloth, and the number of pile picks. In this case, at least one of the rotational speed of the loom, the weft density, the weft type, the shifting distance of cloth, and the number of pile picks is different between the weaving conditions. Furthermore, each driving condition may be set in view of at least two of a shedding pattern, a rotational speed of the loom, a weft density, and a weft type.

[0012] According to the present invention, the first electrical actuator and the second electrical actuator are driven asynchronously so that the take-up-side terry motion member and the let-off-side terry motion member are driven in different modes. Moreover, the magnitude of the difference in driving modes between the two actuators is changed in correspondence with the weaving conditions. Accordingly, the present invention has the following advantages.

(1) Due to the fact that the balance between the upper yarns and the lower yarns of the shed changes when a shedding pattern is switched to another pattern during a weaving operation, the warp tension changes during the shifting of the terry motion members in response to the switching of the shedding patterns. In this case, the conventional art, in which the difference in driving modes between the two terry motion members is always constant, cannot respond to such a change in the warp tension. For this reason, the warp tension cannot be properly compensated. As a result, this could cause the warp tension to lower, which may lead to a weft-insertion problem caused by a shedding failure due to a dull movement of the warp yarns, or could cause the warp tension to increase by a large degree, which may lead to broken warp yarns.
In contrast, according to the present invention, the difference in driving modes between the two terry motion members, that is, the driving conditions of the two actuators, is set in correspondence with each shedding pattern so that the difference in driving modes can be changed in response to the switching of the shedding patterns. Accordingly, even when the warp tension changes in response to the switching of the shedding patterns, such a change in the warp tension can be compensated, whereby the problems mentioned above can be effectively prevented.

(2) Generally, the driving timing of each terry motion member is determined based on the rotational angle of a main shaft of the loom (crank angle). For this reason, the shifting speed of each terry motion member is different according to the rotational speed of the loom. In other words, in a case where each terry motion member is shifted by the same distance within the same range of the rotational angle of the main shaft, it is natural that the shifting speed of the terry motion member is different according to the rotational speed of the loom. Consequently, if the shifting speed is different according to the rotational speed of the loom, the inertia forces acting upon the terry motion members during the reverse shifting of the terry motion members may vary. This means that the effect on the warp yarns may also vary.
When the rotational speed of the loom is changed during a weaving operation, the effect on the warp yarns changes due to the inertia forces mentioned above. For this reason, the warp tension may become too high or too low, thus causing the same problems described above with regard to the switching of the shedding patterns. In contrast, according to the present invention, the terry motion members are given different driving amounts in order to compensate for the warp tension, and moreover, the difference in driving amounts can be changed in correspondence with the rotational speed of the loom. Accordingly, the problems mentioned above can be effectively prevented.

(3) When the weft density is changed to a higher density or when the weft yarn to be inserted is changed to a thicker type while the weft density is maintained at the same density, a sufficient warp tension that corresponds to such a change must be attained. Or else, the beating properties may deteriorate and an overhanging phenomenon of the cloth (a phenomenon in which the cloth fell retreats in response to the retreating of the reed after the beating operation) may be induced. This is problematic in view of the quality of the cloth.
According to the conventional art, when the weft density or the weft type is changed during a weaving operation, if the difference in driving modes between the terry motion members is set such that the warp tension corresponds to, for example, the previous weft density, a sufficient warp tension that corresponds to, for example, the subsequent weft density cannot be attained. For this reason, the conventional art is problematic in not having the capability to respond to a high-weft-density weaving operation or to a weaving operation that uses a thick type of weft yarn. In order to obtain a sufficient warp tension after the switching of the weft densities or the weft types, it is possible to set the warp tension constantly at a high value for the beating operation. However, setting the warp tension constantly at a high value could increase the possibility of warp-yarn breakage in response to the impact of the beating motion. For this reason, it is undesirable to set the warp tension constantly at a high value for the beating operation.
In contrast, according to the present invention, the difference in driving modes between the terry motion members can be set in correspondence with the weft density or the weft type for each weaving operation. Accordingly, while significantly reducing the possibility of warp-yarn breakage, the present invention is capable of responding to switching of a weaving operation to a higher-density weaving operation or to a weaving operation that uses a thicker type of weft yarn.
Furthermore, when the set warp tension is to be changed to another warp tension, if the difference in driving modes between the terry motion members is constantly fixed, as in the conventional art, a sufficient warp tension for the beating operation cannot be obtained in both the weaving operation with the previous warp tension and the weaving operation with the subsequent warp tension. This is problematic in that the beating properties may deteriorate or that the possibility of warp-yarn breakage may become higher due to the fact that the warp tension during the beating operation is kept constantly at a high value. In contrast, in the present invention, the difference in driving modes between the terry motion members can be set in correspondence with the set warp tension, whereby the problems mentioned above can be effectively prevented.

(4) In a case where the shifting distance of cloth is changed during a weaving operation, namely, in a case where the pile length of cloth being woven is changed, the shifting distance of each terry motion member is changed accordingly. Specifically, if the shifting distance of cloth (pile length) is changed to a larger value, for example, the inertia forces acting upon the terry motion members during the reverse shifting thereof become larger in comparison with the inertia forces according to the previous shifting distance. This may increase the effect on the warp yarns. Accordingly, the same problems occur as in the case where the rotational speed of the loom is changed.
In contrast, according to the present invention, the difference in driving modes between the terry motion members is set in correspondence with the shifting distance of cloth such that the difference in driving modes can be changed in accordance with the change in the shifting distance of cloth. Accordingly, the problems mentioned above can be effectively prevented.

(5) In a case where the number of pile picks (the number of weft insertions in one unit for pile formation) is changed, specifically, in a case where the number of beating operations for the first pick is changed, the beating properties of the weft yarns and the impact applied to the warp yarns during the beating operation may vary. In comparison with a case where one beating operation is performed for the first pick, the beating properties of the weft yarns is better when two beating operations are performed for the first pick. On the other hand, the impact applied to the warp yarns in this case becomes greater. For example, the number of pile picks is set to three picks (one beating operation for the first pick) and the difference in driving modes between the terry motion members is set such that a high warp tension is obtained for the beating operation in order to achieve better beating properties of the weft yarns. In this case, if the number of pile picks is changed (to, for example, four pile picks) and two beating operations are to be performed for the first pick, the possibility of warp-yarn breakage may become higher due to the impact applied to the warp yarns. On the other hand, for example, when the difference in driving modes between the terry motion members is set in correspondence with a case where two beating operations are performed for the first pick, if the number of pile picks is changed to three picks, the beating properties of the weft yarns, for example, may deteriorate.

[0013] In contrast, according to the present invention, the difference in driving modes between the terry motion members is set in correspondence with the number of pile picks such that the difference in driving modes can be changed in accordance with the change in the number of pile picks. Accordingly, the problems mentioned above can be effectively prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] 

Fig. 1 is a side view illustrating a relevant section of a cloth-shifting-type pile loom 1;

Fig. 2 is an enlarged side view of a terry motion mechanism 20 included in the cloth-shifting-type pile loom 1;

Fig. 3 is a block diagram illustrating a control section of the cloth-shifting-type pile loom 1; and

Figs. 4A and 4B are diagrams illustrating driving patterns of let-off-side and take-up-side terry motion members (let-off-side tension roller 7 and take-up-side cloth guide roller 18).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Fig. 1 illustrates an example of a cloth-shifting-type pile loom 1 according to the present invention. Fig. 2 illustrates a terry motion mechanism 20 of the cloth-shifting-type pile loom 1. In Fig. 1, pile warp yarns 4 for pile formation are fed from an upper warp beam 2 and are wound around guide rollers 8 and a pile-warp tension roller 6 so as to be supplied to a cloth fell 11 of cloth 13 via a heald 9 and a reed 10. In order to apply an appropriate tension to the pile warp yarns 4, the pile-warp tension roller 6 is supported by tension-applying means 19 in a movable manner in the front-back direction such that the pile-warp tension roller 6 is biased in a direction for applying a predetermined tension to the pile warp yarns 4.

[0016] On the other hand, ground warp yarns 5 for ground weaving are fed from a lower warp beam 3 and are wound around a ground-warp tension roller 7 so as to be supplied to the cloth fell 11 of the cloth 13 via the heald 9 and the reed 10. The pile warp yarns 4 and the ground warp yarns 5 are interwoven with each weft yarn 12 inserted in a shed, whereby the cloth 13 of pile fabric is formed. The cloth 13 of pile fabric is subsequently guided by a cloth guide roller 18, a take-up roller 14, a guide roller 15, and a guide roller 16 so as to be finally taken up by a cloth roller 17.

[0017] The ground-warp tension roller 7 defines a let-off-side terry motion member, whereas the cloth guide roller 18 defines a take-up-side terry motion member. The ground-warp tension roller 7 is supported by a rocking lever unit 22 and a rocking shaft 24 in a rocking manner in the front-back direction with respect to, for example, a loom frame (not shown). On the other hand, the cloth guide roller 18 is supported by a rocking lever unit 21 and a rocking shaft 23 in a rocking manner in the front-back direction with respect to, for example, the loom frame (not shown).

[0018] The ground-warp tension roller 7 and the cloth guide roller 18 defining the terry motion members may be unrotatable or rotatable, and are supported by the terry motion mechanism 20 in a movable manner in the front-back direction. During a first pick, the ground-warp tension roller 7 and the cloth guide roller 18 are set at a backward-limit position where the amount of terry motion is zero, that is, a first-pick position F corresponding to a beating position. On the other hand, during a loose pick, the ground-warp tension roller 7 and the cloth guide roller 18 are set at a forward-limit position where the amount of terry motion is present, that is, a loose-pick position L. The first-pick position F and the loose-pick position L will be described below in detail with reference to the ground-warp tension roller 7 and the cloth guide roller 18 in Figs. 4A and 4B.

[0019] The top ends of the rocking lever units 21, 22 are respectively linked with the top ends of two rocking lever units 36, 37 disposed at the central section of the terry motion mechanism 20. Specifically, the top ends of the rocking lever units 21, 22 are respectively linked with the top ends of two rocking lever units 36, 37 via linking rods 25, 26 and linking pins 27, 28 disposed at opposite ends of the linking rods 25, 26. The lengths of the linking rods 25, 26 can be adjusted with screws (not shown) provided at the opposite ends thereof. The rocking lever unit 36 is supported by a spindle 38 in a rotatable manner with respect to, for example, the loom frame (not shown). On the other hand, the rocking lever unit 37 is supported by a spindle 39 in a rotatable manner with respect to, for example, the loom frame (not shown).

[0020] Intermediate sections of the rocking lever units 36, 37 are respectively linked with front end portions of cranks 31, 32 via link components 29, 30 and linking pins 33, 34 disposed at opposite ends of the link components 29, 30. The base end portions of the cranks 31, 32 are respectively attached to a driving shaft 40 of a first electrical actuator 41 and a driving shaft 43 of a second electrical actuator 42 in a rotatably-locked fashion.

[0021] The first electrical actuator 41 and the second electrical actuator 42 are designated electrical actuators that operate in synchronization with the rotation of a main shaft 35 of the loom 1. In detail, the first electrical actuator 41 and the second electrical actuator 42 are electrical servo-motors that are individually controlled by a loom-controlling computer 50 shown in Fig. 3 in an asynchronous manner with respect to each other.

[0022] During a weaving operation, the rotation of the first electrical actuator 41 is converted to a rocking motion by the crank 31, the link component 29, the rocking lever unit 36, the linking rod 25, and the rocking lever unit 21. The rocking motion is transmitted to the cloth guide roller 18 serving as the take-up-side terry motion member. On the other hand, the rotation of the second electrical actuator 42 is converted to a rocking motion by the crank 32, the link component 30, the rocking lever unit 37, the linking rod 26, and the rocking lever unit 22. The rocking motion is transmitted to the ground-warp tension roller 7 serving as the let-off-side terry motion member.

[0023] Accordingly, the cloth guide roller 18 and the ground-warp tension roller 7 are rocked in an asynchronous manner so as to move in the front-back direction. Therefore, the cloth 13 of pile fabric is moved in the front-back direction in response to the weaving operation of the cloth-shifting-type pile loom 1, whereby the cloth fell 11 reciprocates between the first-pick position F and the loose-pick position L. Accordingly, the terry motion mechanism 20 asynchronously moves the cloth guide roller 18 and the ground-warp tension roller 7 in the front-back direction so as to change the distance between the cloth guide roller 18 and the ground-warp tension roller 7. As a result, the tension of the pile warp yarns 4 and the tension of the ground warp yarns 5 are adjusted to appropriate values for pile formation.

[0024] When the cloth fell 11 is at the loose-pick position L, the inserted weft yarn 12 is not completely beaten against the cloth fell 11 for the purpose of preparing for pile formation. Therefore, the incompletely beaten weft yarn 12 and the cloth fell 11 form a distance therebetween that corresponds to the amount of terry motion (i.e. an amount of reed clearance). In contrast, when the cloth fell 11 is at the first-pick position F, the inserted weft yarn 12 is completely beaten against the cloth fell 11. During the beating motion of the first pick following the beating motion of the loose pick, the cloth fell 11 is retreated to the beating position (i.e. the first-pick position F) where the weft yarn 12 is completed beaten against the cloth fell 11. As a result, the pile warp yarns 4 form piles having a length that corresponds to the amount of terry motion (i.e. the amount of reed clearance).

[0025] Specifically, the terry motion mechanism 20 includes the link mechanism (i.e. a combination of the crank-lever units and the lever units) which is driven based on the rotations of the first electrical actuator 41 and the second electrical actuator 42. The first electrical actuator 41, the second electrical actuator 42, and the link mechanism (the combination of the crank-lever units and the lever units) are designed to predetermined dimensions in view that desired movements are attained for the cloth guide roller 18 defining the take-up-side terry motion member and the ground-warp tension roller 7 defining the let-off-side terry motion member. The cloth guide roller 18 and the ground-warp tension roller 7 are capable of being reciprocated between the first-pick position F and the loose-pick position L at individual timings, or may be stopped at one of the positions F and L.

[0026] Instead of being defined by the combination of the link mechanism and the electrical actuators (the first electrical actuator 41 and the second electrical actuator 42) that operate in synchronization with the rotation of the main shaft 35, the terry motion mechanism 20 may alternatively be defined by a combination of a cam mechanism and electrical actuators that operate in synchronization with the rotation of the main shaft 35.

[0027] As will be described below in detail, the magnitude of the difference in driving amounts between the first electrical actuator 41 and the second electrical actuator 42 varies depending on weaving operations performed under different weaving conditions. In order to achieve this, a driving condition corresponding to each weaving condition is set for at least one of the electrical actuators. When the weaving condition is switched to another weaving condition during a weaving operation, the driving condition for one of or each of the electrical actuators is changed.

[0028] Fig. 3 illustrates the loom-controlling computer 50 for controlling the driving operation of the first electrical actuator 41 and the second electrical actuator 42; a weaving-condition setting device 46 connected to an input side of the loom-controlling computer 50; a driving-condition setting device 47; a rotation detector 48, such as an encoder; and first drive-control means 44 and second drive-control means 45 which are connected to an output side of the loom-controlling computer 50.

[0029] The first drive-control means 44 includes a control circuit 51 which receives an output from the loom-controlling computer 50 and an output from the rotation detector 48, and an amplification circuit 53 which receives an output from the control circuit 51 so as to drive the first electrical actuator 41. On the other hand, the second drive-control means 45 includes a control circuit 52 which receives an output from the loom-controlling computer 50 and an output from the rotation detector 48, and an amplification circuit 54 which receives an output from the control circuit 52 so as to drive the second electrical actuator 42.

[0030] Referring to Fig. 3, various set values for a plurality of weaving-related parameters included in each weaving condition are set in the loom-controlling computer 50. Specifically, the weaving-related parameters include, for example, a shedding pattern, the rotational speed of the loom 1, the weft density, the weft type, and the warp tension. During a continuous operation of the cloth-shifting-type pile loom 1, at least one of the weaving-related parameters is changeable. Accordingly, a plurality of condition settings can be set in the loom-controlling computer 50 with respect to at least one changeable weaving-related parameter. On the other hand, in a case where a plurality of weaving conditions are set such that at least one of the weaving-related parameters is set differently between the weaving conditions, a switch timing is additionally set. In this case, this switch timing is set based on, for example, a cycle number in a weaving operation.

[0031] The loom-controlling computer 50 is provided with a counter (pick counter), which is not shown, for counting the number of cycles of the loom 1. This pick counter performs a count-up operation every time a predetermined main-shaft angle (for example, 0°) is detected based on a signal from the rotation detector 48 provided for the main shaft 35. In contrast, the pick counter performs a count-down operation when the main shaft 35 rotates in the reverse direction.

[0032] Based on the set weaving condition and the set cycle number, the loom-controlling computer 50 outputs a driving signal to each of devices included in the cloth-shifting-type pile loom 1 (such as a main driving device, a weft-insertion device, a shedding device, a take-up device, and a let-off device).

[0033] The driving-condition setting device 47 sets the driving conditions of the two electrical actuators (i.e. the first electrical actuator 41 and the second electrical actuator 42) for respectively driving the two terry motion members (i.e. the cloth guide roller 18 and the ground-warp tension roller 7). Consequently, each driving condition includes a pile pattern (the number of pile picks and the length of the piles); the driving distance (the amount of rotation of each electrical actuator for moving the corresponding terry motion member by a predetermined distance); the driving timing (the timing for retreating each terry motion member from the forward-limit position in order to perform the beating operation for the first pick, and the end timing at which each terry motion member reaches the forward-limit position when the terry motion member is shifted from the backward-limit position toward the forward-limit position); and a speed pattern (the transition pattern of speed of each terry motion member in the process of the movement from the forward-limit position towards the backward-limit position or from the backward-limit position towards the forward-limit position).

[0034] According to the present invention, a plurality of set values can be set in the driving-condition setting device 47 with respect to a driving condition for one of or each of the first electrical actuator 41 of the take-up side and the second electrical actuator 42 of the let-off-side. Specifically, each driving condition may include at least one of the driving distance, the driving timing, and the speed pattern.

[0035] The loom-controlling computer 50 outputs the driving condition for the first electrical actuator 41 set in the driving-condition setting device 47 to the control circuit 51 in the first drive-control means 44, the driving condition corresponding to the current weaving condition. Based on the set timing and the set driving distance in the output driving condition, the control circuit 51 drives and controls the corresponding first electrical actuator 41 via the amplification circuit 53. Similarly, the loom-controlling computer 50 outputs the driving condition for the second electrical actuator 42 set in the driving-condition setting device 47 to the control circuit 52 in the second drive-control means 45, the driving condition corresponding to the current weaving condition. Based on the set timing and the set driving distance in the output driving condition, the control circuit 52 drives and controls the corresponding second electrical actuator 42 via the amplification circuit 54.

[0036] An embodiment of a specific operation of the cloth-shifting-type pile loom 1 according to the present invention will now be described. Specifically, while the pile-fabric cloth 13 is woven to a predetermined length in a continuous operation of the cloth-shifting-type pile loom 1, a portion of the cloth 13 is woven under a weaving condition that is different from the weaving condition for the other portion woven with a different weft density and a different weft type.

[0037] The present invention may also be applied to an example in which a predetermined unit length is woven under a predetermined weaving condition and the subsequent predetermined unit length is woven under a weaving condition different from the previous weaving condition, or to an example in which multiple types of weft yarns 12 are used for the weaving operation such that the type of weft yarn 12 inserted is changed for every predetermined number of picks. In these examples, the operation of the cloth-shifting-type pile loom 1 is performed in the same manner.

[0038] Accordingly, in this embodiment, the weaving operation is performed under two types of weaving conditions (i.e. weaving condition A and weaving condition B) between which the weft density and the weft type included in the weaving-related parameters are different. Consequently, two types of set values for each of the weft density and the weft type included in the weaving-related parameters are set in the weaving-condition setting device 46.

[0039] Furthermore, as the driving condition to be changed in this embodiment, the driving distance of the second electrical actuator 42 may be changed. Accordingly, two types of driving distances for the second electrical actuator 42, which correspond to the two respective weaving conditions, are set in the driving-condition setting device 47. The magnitude of each of the driving distances is set in view of the content of the corresponding weaving-related parameters in each weaving condition.

[0040] Figs. 4A and 4B are diagrams illustrating the driving patterns of the let-off-side and take-up-side terry motion members (let-off-side tension roller 7 and take-up-side cloth guide roller 18) according to this embodiment. Figs. 4A and 4B illustrate an example of a triple-weft pile fabric (2L - 1F). Specifically, one unit for pile formation includes three weft yarns, such that one unit is equal to three cycles (three rotations) of the loom 1. In each unit, one weft yarn is inserted for the first pick, and two weft yarns are inserted for the loose picks. The let-off-side tension roller 7 and the take-up-side cloth guide roller 18 are at the forward-limit position (loose-pick position L) when the rotational angle of the main shaft 35 is at 0°. In the subsequent cycle, the let-off-side tension roller 7 and the take-up-side cloth guide roller 18 are shifted to the backward-limit position (first-pick position F) in which the rotational angle of the main shaft 35 is at 0°. Moreover, in the subsequent cycle, the let-off-side tension roller 7 and the take-up-side cloth guide roller 18 are shifted to the forward-limit position (loose-pick position L) in which the rotational angle of the main shaft 35 is at 0°. In the final cycle, the let-off-side tension roller 7 and the take-up-side cloth guide roller 18 are maintained at the forward-limit position (loose-pick position L).

[0041] Referring to Fig. 4A, the driving pattern for the cloth guide roller 18 in a moving state substantially forms a sinusoidal waveform. On the other hand, the driving pattern for the ground-warp tension roller 7 in a moving state changes drastically from the middle of the rising phase with respect to a sinusoidal waveform (indicated by a dotted line) so as to form a curve with high acceleration. In the subsequent falling phase, the driving pattern changes gradually with respect to the sinusoidal waveform (indicated by the dotted line) so as to form a curve with low acceleration. Accordingly, in the present invention, the ground-warp tension roller 7 serving as the let-off-side terry motion member and the cloth guide roller 18 serving as the take-up-side terry motion member are driven based on different driving modes (i.e. different timings and different speed patterns in the drawings). In other words, the first electrical actuator 41 corresponding to the cloth guide roller 18 and the second electrical actuator 42 corresponding to the tension roller 7 are driven and controlled in an asynchronous manner.

[0042] Furthermore, Fig. 4B illustrates an example in which the weaving condition is switched from weaving condition A to weaving condition B during a continuous operation of the loom 1. Weaving condition B has a weft density and a weft type of the weaving-related parameters that are different from those in weaving condition A. In this case, the weft density and the weft type in weaving condition B require higher warp tension during the beating operation for the first pick than those in weaving condition A. Therefore, as shown in Fig. 4B, the driving distance of the ground-warp tension roller 7 in weaving condition B is set in the driving-condition setting device 47 at a higher value (backward-limit position indicated by a dotted line) than that in weaving condition A.

[0043] In this case, the loom-controlling computer 50 determines switching of the weaving conditions based on the count value of the pick counter (loom cycle number), and outputs a command signal to the relevant devices (take-up device, weft-insertion device, etc.) in order to switch the driving modes. Moreover, the loom-controlling computer 50 also outputs the driving distance corresponding to the switched condition to the control circuit 52 in the second drive-control means 45. Accordingly, under the switched weaving condition, the second drive-control means 45 controls the driving operation of the second electrical actuator 42 based on an amount of rotation greater than that in the previous weaving condition. This changes the backward shifting distance of the ground-warp tension roller 7 (let-off-side terry motion member), whereby the warp tension during the beating operation of the first pick is increased.

[0044] Although not shown in the drawings, in a case where the weaving condition is switched back from weaving condition B to weaving condition A, the loom-controlling computer 50 outputs the driving distance corresponding to weaving condition A in response to the switching of the weaving conditions. Thus, the second drive-control means 45 drives the second electrical actuator 42 based on the corresponding amount of rotation.

[0045] Accordingly, the cloth-shifting-type pile loom 1 drives the let-off-side terry motion member (ground-warp tension roller 7) and the take-up-side terry motion member (cloth guide roller 18) individually via the designated second electrical actuator 42 and first electrical actuator 41, respectively, such that the let-off-side second electrical actuator 42 and the take-up-side first electrical actuator 41 are driven in an asynchronous manner. Moreover, the magnitude of the difference in driving amounts between the first electrical actuator 41 and the second electrical actuator 42 varies depending on weaving operations performed under different weaving conditions. This is achieved by setting a driving condition corresponding to each weaving condition in the weaving-condition setting device 46 for at least one of the first electrical actuator 41 and the second electrical actuator 42. When the weaving condition is switched during a weaving operation, the loom-controlling computer 50 changes the driving condition for one of or each of the first electrical actuator 41 and the second electrical actuator 42.

[0046] The technical scope of the present invention is not limited to the above embodiment, and modifications are permissible within the scope and spirit of the present invention.

1. Although the above embodiment describes an example in which a continuous operation is performed under two types of weaving conditions between which the two weaving-related parameters, i.e. the weft density and the weft type, are different, the present invention is not limited to such an example. For example, the present invention may alternatively be applied to an example in which the continuous operation is performed under two or more weaving conditions between which at least one of the weaving-related parameters is different.

2. Although the above embodiment describes an example in which the first electrical actuator 41 and the second electrical actuator 42 are driven asynchronously so that the two terry motion members are shifted from the forward-limit position to the backward-limit position or from the backward-limit position to the forward-limit position at different driving timings and with different speed patterns, the present invention is not limited to such an example. For example, the two terry motion members may alternatively be driven at the same driving timing but with different speed patterns and by different driving distances, or the two terry motion members may be driven at the same driving timing and by the same driving distance but with different speed patterns. Furthermore, although the above embodiment describes an example in which the driving distance of the second electrical actuator 42 for driving the let-off-side terry motion member is changed in response to the switching of the weaving conditions, the present invention is not limited to such an example. Alternatively, the driving timing or the speed pattern may be changed in response to the switching of the weaving conditions. As a further alternative, these multiple parameters in the driving conditions may be changed simultaneously. Due to the fact that the driving distance of the take-up-side terry motion member (first electrical actuator 41) directly affects the shifting distance (pile length) of the cloth 13, it is basically preferable that the driving distance is kept constant. However, in a case where, for example, the rotational speed of the loom 1 is changed, the magnitude of inertia force acting on the take-up-side terry motion member changes. This may cause the shifting distance to change even if the set driving distance is the same. In such a case, the driving condition of the first electrical actuator 41 may be set in correspondence with each of multiple weaving conditions between which the rotational speed of the loom 1 is different.

3. Although the above embodiment describes an example in which the switching of the weaving conditions is performed at weaving intervals, the present invention is not limited to such an example. For example, in a case where a weaving operation is performed using multiple types of weft yarns, a driving condition of the second electrical actuator 42 may be set for each type of weft yarn, such that the driving condition is changed every time the corresponding type of weft yarn is to be inserted.

4. Although the above embodiment describes an example in which servo-motors are used as the first electrical actuator 41 and the second electrical actuator 42 for driving the two respective terry motion members, linear motors may alternatively be used as the electrical actuators. In that case, the two terry motion members are driven linearly by the linear motors.

Claims

1. A pile-formation method in a cloth-shifting-type pile loom (1) which drives a take-up-side terry motion member (18) and a let-off-side terry motion member (7) individually with designated first and second electrical actuators (41, 42), respectively, the pile-formation method comprising the steps of:

driving the second electrical actuator (42) for the let-off-side terry motion member (7) and the first electrical actuator (41) for the take-up-side terry motion member (18) in an asynchronous manner, wherein a driving condition corresponding to each of a plurality of weaving conditions is set for at least one of the electrical actuators (41, 42) such that a magnitude of a difference in driving amounts between the electrical actuators (41, 42) varies depending on weaving operations performed under different weaving conditions; and

changing the driving condition of one of or each of the electrical actuators (41, 42) when a weaving condition is switched to another weaving condition during a weaving operation.

2. A pile-formation device included in a cloth-shifting-type pile loom (1), comprising:

a first electrical actuator (41) for driving a take-up-side terry motion member (18);

a second electrical actuator (42) for driving a let-off-side terry motion member (7);

a driving-condition setting device (47) for setting driving conditions for the first electrical actuator (41) and the second electrical actuator (42); and

drive-control means (44, 45) for driving the electrical actuators (41, 42) based on the driving conditions set in the driving-condition setting device (47),

wherein the cloth-shifting-type pile loom (1) drives the first electrical actuator (41) and the second electrical actuator (42) in an asynchronous manner based on different driving conditions so that the take-up-side terry motion member (18) and the let-off-side terry motion member (7) are driven in different modes, and
wherein the driving-condition setting device (47) sets a plurality of driving conditions for at least one of the electrical actuators (41, 42).

3. The pile-formation method according to Claim 1, wherein each weaving condition includes a rotational speed of the loom (1), a weft density, a weft type, a shifting distance of cloth, and the number of pile picks, and
wherein at least one of the rotational speed of the loom (1), the weft density, the weft type, the shifting distance of cloth, and the number of pile picks is different between the weaving conditions.

4. The pile-formation device according to Claim 2, wherein each driving condition is set in view of at least two of a shedding pattern, a rotational speed of the loom (1), a weft density, and a weft type.

Drawing