Tatami stitching device

Abstract

The objective is to provide a tatami mat sewing device capable of detecting thread breakage. [Solution] A tatami sewing device according to one aspect of the present invention is a tatami sewing device for sewing tatami mats, comprising a thread breakage prediction means for predicting thread breakage of the upper thread and / or lower thread sewing machine thread, wherein the thread breakage prediction means comprises a detection sensor for detecting the amount of thread used and a control means, and the control means comprises a thread breakage determination means which determines that thread breakage has occurred when the sum of the cumulative amount of thread actually used measured by the detection sensor and a predetermined predicted amount of thread used exceeds the initial set amount of thread.

Description

Technical Field

[0001] The present invention relates to a tatami sewing device for sewing tatami, such as sewing a tatami edge to the side of a tatami, and particularly to a tatami sewing device capable of determining thread breakage.

Background Art

[0002] Conventionally, in the manufacturing process of tatami, a hemming process of sewing a tatami surface to the side surface of the short side of the tatami and a return sewing process of sewing a tatami edge to the side surface of the long side of the tatami have been carried out.

[0003] During the sewing of the tatami, thread breakage may occur due to some trouble or using up all the thread. In that case, the operator has to perform replacement work such as untying the sewing thread from under the tatami while the tatami is placed on the device, which is very time-consuming. Also, stitches may form at the part where the thread is added, leading to deterioration of the finish.

[0004] Therefore, the applicant of the present application has previously proposed a thread breakage detection device for detecting thread breakage of a sewing thread (see Patent Document 1). The thread breakage detection device of Patent Document 1 is provided with a speed detector 19 for detecting the running speed when the upper thread runs on the upper thread supply side, compares the upper thread running speed detected by this speed detector 19 with the upper thread lower limit speed set in advance in the speed setter, and includes a thread breakage determination means for outputting a stop signal when the upper thread running speed is smaller than the upper thread lower limit speed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the thread breakage detection device described in Patent Document 1 is a device specifically designed for thick tatami mats and cannot be applied to thin tatami mats. Furthermore, the thread breakage detection device described in Patent Document 1 detects thread breakage after it has occurred, such as when the thread is cut midway for some reason or when the thread is used up, and does not stop before the thread breaks.

[0007] If the machine stops only after the thread breaks, the needle will still be operating immediately before and after the break, resulting in loose stitching and a messy seam. Furthermore, if the machine is notified in this state, the operator will have to change the thread in a cramped space with the tatami mat still on the machine, which is extremely time-consuming. In addition, if the thread breaks while sewing the tatami mat, the machine will need to be re-stitched, resulting in a poor finish.

[0008] The present invention has been made in view of the above problems, and aims to provide a tatami sewing device that can predict thread breakage before it occurs. [Means for solving the problem]

[0009] A tatami sewing device according to one aspect of the present invention is a tatami sewing device for sewing tatami mats, comprising a thread breakage prediction means for predicting thread breakage of the upper thread and / or lower thread sewing machine thread, wherein the thread breakage prediction means comprises a detection sensor for detecting the amount of thread used and a control means, and the control means comprises a thread breakage determination means for determining thread breakage when the sum of the cumulative amount of thread actually used measured by the detection sensor and a predetermined predicted amount of thread used exceeds the initial set amount of thread.

[0010] Here, the initial thread set amount refers to the amount of sewing thread set at the start of sewing. For example, if unused sewing thread is used, the initial thread set amount will be the amount of unused sewing thread. If used sewing thread, it will refer to the remaining amount of thread obtained by subtracting the amount of used sewing thread from the amount of unused sewing thread. With this configuration, a thread break is determined when (cumulative amount of thread consumed) + (predetermined predicted amount of thread used) > (initial thread set amount). In other words, a thread break is determined when (predetermined predicted amount of thread used) > (current amount of sewing thread remaining).

[0011] This allows for detection of thread breakage before the thread actually breaks, and enables the device to be stopped before the thread breaks. This prevents the unsightly appearance of the seam caused by sewing continuing with a completely broken thread, and also prevents the seam from looking bad when it is resewn midway through, as thread replacement is easier.

[0012] Furthermore, this tatami sewing device is characterized in that the predetermined predicted amount of thread used is the amount of thread used to sew one tatami mat.

[0013] According to this configuration, a thread break is detected when (cumulative thread consumption) + (amount of thread used to sew one tatami mat) > (initial set amount). In other words, a thread break is detected when (amount of thread used to sew one tatami mat) > (current amount of sewing machine thread). In other words, this ensures that thread breakage is detected before it actually occurs, preventing thread breakage during the sewing of a single tatami mat. Therefore, thread changes can be performed smoothly by the worker, and the appearance of the stitching can be minimized.

[0014] Furthermore, this tatami sewing device is characterized in that the predetermined predicted amount of thread used is the amount of thread used to sew a tatami mat of the maximum length.

[0015] With this configuration, regardless of the size of the tatami mat, thread breakage can be reliably detected before it occurs during the sewing process of a single mat. Therefore, regardless of the size of the tatami mat, the worker can change the thread smoothly, and the appearance of the stitching can be minimized.

[0016] Furthermore, this tatami sewing device is characterized in that, when the thread breakage prediction means replaces the sewing thread, the initial set amount of thread is reset and the cumulative amount of thread consumed starts counting from 0.

[0017] With this configuration, the count is reset each time the thread is changed, making it possible to detect the amount of thread used and, consequently, predict when the thread will break, based on the amount of thread remaining after the change.

[0018] This tatami sewing device is characterized in that, if the thread breakage detection means determines that a thread has broken during the sewing of a tatami mat being worked on, it stops the sewing work after the sewing of the tatami mat being worked on is completed, or the thread breakage detection means determines that a thread has broken after the sewing of the tatami mat being worked on is completed, or the thread breakage detection means determines that a thread has broken between the completion of sewing of the tatami mat being worked on and the start of sewing of the next tatami mat.

[0019] With these configurations, the device can be stopped after the sewing of the tatami mat in progress is completed without the thread breaking. This allows the operator to smoothly change the thread before starting the sewing of the next tatami mat, even when the tatami mat is not in the device.

[0020] This tatami sewing device is further characterized by comprising a notification means that notifies the operator of thread breakage when the thread breakage detection means determines that the thread has broken.

[0021] This configuration allows the worker to know when the thread is about to break and replace it at the appropriate time.

[0022] This tatami sewing device is further characterized by comprising remaining amount display means for displaying the remaining amount of the thread.

[0023] According to this configuration, since the operator can know the remaining amount of the sewing thread at any time, the timing for replacing the thread can be adjusted.

[0024] This tatami sewing device is characterized by comprising input means for inputting and setting a numerical value for the initial set amount of the thread.

[0025] According to this configuration, when the actual remaining amount of the thread is known by measurement or the like, more accurate prediction of thread breakage becomes possible. In the case of unused sewing thread, since the amount of the thread is known in advance, it is only necessary to input the numerical value of the amount of the thread.

[0026] This tatami sewing device is characterized in that the thread breakage prediction means predicts the thread breakage of the upper sewing thread.

[0027] According to this configuration, it becomes possible to measure the cumulative consumed amount of the upper thread and predict thread breakage.

[0028] This tatami sewing device is characterized in that the detection sensor is an encoder attached to a roller through which the thread is wound and passed, and the cumulative consumed amount of the thread is calculated by multiplying the number of rotations of the roller by the unit thread amount fed out in one rotation.

[0029] According to this configuration, it becomes possible to easily detect the amount of thread used. That is, the amount of thread used can be detected by the number of rotations of the roller provided with the encoder.

[0030] This tatami sewing device further comprises a thread holding portion for installing the sewing thread, and the roller to which the encoder is attached is arranged on the path from the thread holding portion to the sewing needle and between two tension members for applying tension to the sewing thread.

[0031] With this configuration, the roller equipped with the encoder is located on the needle side of the tension member that applies tension to the sewing thread, and near the tension member, that is, in a location where the thread is less likely to loosen, thereby enabling accurate detection of the amount of thread used.

[0032] This tatami sewing device is characterized in that the thread breakage prediction means predicts the breakage of the lower thread sewing machine thread.

[0033] This configuration makes it possible to measure the cumulative amount of yarn consumed by the lower thread and to predict yarn breakage.

[0034] This tatami sewing device is used by winding the sewing thread onto a bobbin, the detection sensor is an encoder attached to the bobbin, or an encoder attached to a disk that rotates in conjunction with the rotation of the bobbin, and the cumulative amount of thread consumed is calculated by multiplying the number of rotations of the bobbin or disk by the amount of thread dispensed per rotation.

[0035] This configuration makes it easy to detect the amount of yarn used. Specifically, the amount of yarn used can be detected by the rotation speed of the disk to which the encoder is attached or the rotation speed of the bobbin.

[0036] Furthermore, this tatami sewing device is characterized in that the initial amount of thread set is the initial amount of thread measured by a measuring means that measures the amount of thread wound when the sewing thread is wound onto the bobbin.

[0037] This configuration allows for more accurate prediction of yarn breakage, as it is based on the measured initial yarn quantity.

[0038] This tatami sewing device is characterized in that the thread breakage prediction means predicts thread breakage of the upper and lower sewing threads, and is capable of determining two thread breakages: a first thread of either the upper or lower sewing thread, and a second thread of either the upper or lower sewing thread. The thread breakage determination means comprises: a first thread breakage determination means that determines thread breakage of the first thread when the sum of the cumulative amount of thread consumed by the first thread actually used, as measured by the detection sensor, and the predicted amount of thread used by the first thread exceeds the initial set amount of thread for the first thread; and a second thread breakage determination means that determines thread breakage of the second thread when the sum of the cumulative amount of thread consumed by the second thread, calculated by multiplying the cumulative amount of thread consumed by the first thread by a predetermined coefficient, and the predicted amount of thread used by the second thread exceeds the initial set amount of thread for the second thread.

[0039] This configuration allows a single detection sensor to measure the cumulative amount of thread consumed for both the upper and lower threads, and to predict thread breakage. By preventing thread breakage during sewing, work efficiency is improved.

[0040] One embodiment of the present invention is a tatami sewing device in which the thread breakage prediction means predicts thread breakage of the upper thread and the lower thread, and is capable of determining two thread breakages: a first thread of either the upper thread or the lower thread, and a second thread of either the upper or lower thread, and is equipped with a plurality of detection sensors, the plurality of detection sensors including a first detection sensor for detecting the amount of the first thread used and a second detection sensor for detecting the amount of the second thread used, and the thread breakage determination means comprises a first thread breakage determination means which determines that the first thread has broken if the sum of the cumulative amount of thread actually used by the first thread measured by the first detection sensor and the predicted amount of thread used by the first thread exceeds the initial set amount of thread for the first thread, and a second thread breakage determination means which determines that the second thread has broken if the sum of the cumulative amount of thread actually used by the second thread measured by the second detection sensor and the predicted amount of thread used by the second thread exceeds the initial set amount of thread for the second thread.

[0041] This configuration allows for more accurate measurement of the cumulative thread consumption of both the upper and lower threads, as well as prediction of thread breakage, by attaching detection sensors to both. This improves work efficiency by preventing thread breakage during sewing. [Effects of the Invention]

[0042] According to the present invention, it is possible to predict the breakage of sewing thread used for sewing tatami mats. [Brief explanation of the drawing]

[0043] [Figure 1] This is a plan view showing the schematic configuration of a tatami mat sewing device. [Figure 2] This is a side view showing the schematic configuration of a tatami mat sewing device. [Figure 3] This is a front view of the sewing machine body. [Figure 4] This is a side view of the sewing machine body with the sewing needle in the upper position. [Figure 5] This is a side view of the sewing machine body with the sewing needle in the lower position. [Figure 6] This is a plan view of the sewing machine body. [Figure 7] This is a magnified cross-sectional view of the tip of a sewing needle. [Figure 8] This diagram shows a sewing machine rotation detection plate that detects the movement of the sewing needle. [Figure 9] This is a front view of the control panel. [Figure 10] This is a schematic side view showing a configuration including a thread breakage prediction means according to the first embodiment of the present invention. [Figure 11] This is a partially enlarged perspective view showing the configuration of the thread breakage detection means according to the first embodiment of the present invention. [Figure 12] This is an explanatory diagram of the thread path for ladder stitch or zigzag stitch. [Figure 13] This figure shows examples of warning displays and battery level indicators on a display. [Figure 14] This is a schematic side view showing a configuration including a thread breakage prediction means according to a second embodiment of the present invention. [Figure 15] This is a partially enlarged perspective view showing the configuration of the bobbin and hook area of ​​the thread break detection means according to a second embodiment of the present invention. [Figure 16] This shows an exploded view (a) of a bobbin and a spool according to a second embodiment of the present invention, a perspective view (b) of the bobbin and spool combined, and a side view (c) of the same. [Figure 17] This diagram shows the relationship between the bobbin, the upper thread, and the lower thread according to a second embodiment of the present invention. [Figure 18] This is a schematic side view showing a configuration including a thread breakage prediction means according to a third embodiment of the present invention. [Figure 19] This is a schematic diagram of a thread winding device that winds thread onto a bobbin. [Modes for carrying out the invention]

[0044] The following describes in detail a tatami sewing device according to one embodiment of the present invention. However, the present invention is not limited by this embodiment. Furthermore, the components in the following embodiment include those that are easily substituted or substantially identical to those that are easily substituted by those skilled in the art. Moreover, the configurations described below can be combined as appropriate. In addition, various omissions, substitutions, or modifications of the configurations can be made without departing from the spirit of the present invention.

[0045] <First Embodiment> [1. Overall configuration of the tatami sewing device] Figure 1 is a plan view showing the schematic configuration of the tatami sewing device of this embodiment, and Figure 2 shows the schematic configuration of the same sewing device. This is a side view showing the scene.

[0046] In this embodiment of the tatami sewing device, the side edge 110 of the tatami 100 refers to the long side of the tatami 100 when it is a full-size tatami mat, and to the side perpendicular or approximately perpendicular to the frame side when it is a half-size tatami mat. Also, in Figure 1, the left-right direction (long side of the tatami) is referred to as direction A, the up-down direction (short side of the tatami) as direction B, and in Figure 2, the up-down direction (thickness direction of the tatami) as direction C.

[0047] As shown in Figures 1 and 2, the tatami sewing device 1 of this embodiment is a device for sewing the edges of tatami mats, and its main components are a sewing machine body 10, a mounting table 11 on which the tatami mat 100 is placed, and a frame 12. The mounting table 11 has a central base extending in direction A in Figure 1, and a plurality of rollers 11A are attached to the left and right of the base at predetermined intervals in direction A. This makes it possible to transport the placed tatami mat 100 along direction A.

[0048] Furthermore, the sewing machine bodies 10 are positioned on both sides of the mounting table 11 in the direction B, which is perpendicular to direction A. With direction A in Figure 1 being the longitudinal direction of the tatami mat 100, and the tatami mat 100 placed on the mounting table 11, the sewing machine bodies 10 are used to perform backstitching on the side edges 110 of the tatami mat 100 while feeding the tatami mat 100 in the direction A, thereby sewing the tatami mat edging to the side edges 110 of the tatami mat 100.

[0049] (2. Components of the sewing machine body) Next, we will describe the main component of the tatami sewing device, the sewing machine body 10. Figure 3 is a front view of the sewing machine body of the sewing device of this embodiment, Figure 4 is a side view of the sewing machine body with the sewing needle in the upper position, Figure 5 is a side view of the sewing machine body with the sewing needle in the lower position, and Figure 6 is a top view of the sewing machine body.

[0050] As shown in Figures 3-6, the sewing machine body 10 is equipped with a sewing mechanism 20, a lifting mechanism 30, and a motor 40 for the lifting mechanism as its main components.

[0051] The sewing mechanism 20 is a mechanism for sewing the tatami mat edge to the side edge 110 of the tatami mat 100. The sewing mechanism 20 performs the sewing operation by oscillating in response to a driving force from the sewing mechanism motor 25.

[0052] The sewing mechanism 20 includes a sewing machine arm 21, a needle arm 22, a cam 23, a connecting member 24, a motor 25 for the sewing mechanism, and a hook 26.

[0053] The sewing machine arm 21 is provided so as to be able to swing around the sewing machine pivot axis 211, which is the pivot axis of the sewing mechanism 20. By swinging the sewing machine arm 21, the height and depth positions of the sewing needle 112 relative to the tatami mat 100 are changed.

[0054] A handle shaft 51 is provided so as to pass through the sewing machine arm 21, and a circular handle 50 is attached to one end of it. The handle 50 is provided for situations where the machine stops due to overload, such as when a foreign object gets caught during sewing, and it is easier to control the needle hook by rotating the handle 50 manually rather than using a motor to determine whether to rotate it in the forward or reverse direction to remove the foreign object. The rotation of the handle shaft 51 causes the sewing machine arm 21 to rotate as a whole. In other words, the handle shaft 51 is the sewing machine pivot shaft 211.

[0055] The needle arm 22 is mounted on the upper part of the sewing machine arm 21 so as to be able to pivot around the sewing needle pivot axis 221. An arc-shaped sewing needle 112 is attached to the tip of the needle arm 22. A sewing thread called the upper thread is threaded through the sewing needle 112.

[0056] The cam 23 rotates under power from the sewing mechanism motor 25, causing the needle arm 22 to oscillate. Furthermore, because the outer circumference of the cam 23 is uneven, the guide roller 71 rotates along the outer circumference of the cam 23, physically determining the amount the balance beam 70 pulls the thread. The rotational force of the sewing mechanism motor 25 is transmitted to the sprocket 52 and handle shaft 51 via the sprocket 252 and chain 60, and the rotation of the handle shaft 51 transmits this force to the cam 23.

[0057] The connecting member 24 has one end rotatably connected to the cam 23 and the other end rotatably connected to the sewing needle pivot shaft 221. The connecting member 24 causes the needle arm 22 to pivot around the sewing needle pivot shaft 221 by the rotation of the cam 23.

[0058] The rotation of the handle shaft 51 is transmitted to the sewing needle oscillating shaft 221 via the connecting member 24, causing the sewing needle oscillating shaft 221 to rotate and the needle arm 22 to oscillate. In other words, the handle shaft 51 acts as the sewing needle drive shaft 113.

[0059] Therefore, the sewing machine's rotating shaft 211 and the sewing needle drive shaft 113 are on the same axis. This reduces the number of parts and simplifies the structure.

[0060] The sewing mechanism motor 25 is located at the end of the sewing mechanism 20. The sewing mechanism motor 25 is fixed in position relative to the sewing machine swivel shaft 211, the sewing needle drive shaft 113, and the sewing needle oscillating shaft 221, and the sewing mechanism motor 25 moves up and down according to the position of the sewing needle 112. As a result, even if the sewing machine swivel shaft 211 and the sewing needle drive shaft 113 are on the same axis, the sewing mechanism motor 25 moves in conjunction with the entire sewing machine, preventing the sewing needle 112 from moving.

[0061] A chain 60 is stretched between a sprocket 252 attached to the rotating shaft 251 of the sewing mechanism motor 25 and a sprocket 52 attached to the handle shaft 51. The rotation of the sewing mechanism motor 25 is transmitted to the handle shaft 51 via the chain 60.

[0062] The needle arm 22 is mounted on the upper part of the sewing machine arm 21 so as to be able to pivot around the sewing needle pivot axis 221. An arc-shaped sewing needle 112 is attached to the tip of the needle arm 22. A sewing thread called the upper thread is threaded through the sewing needle 112.

[0063] The bobbin 26 houses a bobbin 27 wound with sewing thread, called the lower thread for sewing, and rotates in conjunction with the drive of the sewing needle 112. The bobbin 26 is also attached to the tip of the sewing machine arm 21, which vibrates around the sewing machine's pivot axis 211, and rotates synchronously with the needle arm 22 to perform sewing operations.

[0064] The bobbin 26 is attached to the tip of the sewing machine arm 21, and the central axis of the bobbin 26 and the sewing mechanism motor 25 is the sewing machine pivot axis 211, so that the operation of the sewing mechanism 20 is stable.

[0065] The rotational force of the sewing mechanism motor 25 is transmitted to the handle shaft 51 via the sprocket 252 and chain 60. The rotation of the handle shaft 51 causes the bevel gear 263 attached to the handle shaft 51 to rotate, transmitting power to the bobber shaft 261, which in turn transmits power to the bobber 26. In other words, the handle shaft 51 acts as the bobber rotation drive shaft 262, and the bobber rotation drive shaft 262 is on the same axis as the sewing machine swivel shaft 211 and the sewing needle drive shaft 113.

[0066] The lifting mechanism 30 is driven based on the rotation of the motor 40 for the lifting mechanism. As shown in Figures 4 and 5, the lifting mechanism 30 applies a vertical (direction C) movement force to the sewing mechanism 20 by the rotation of the motor 40 for the lifting mechanism, causing the sewing mechanism 20 to oscillate. Figure 4 shows the lifting mechanism 30 in an upward position, and Figure 5 shows it in a downward position.

[0067] The motor 40 for the lifting mechanism is composed of a feedback-controllable servo motor, so it can be driven accurately and quickly. The servo motor may be any type of feedback-controllable servo motor, such as a DC servo motor, an AC servo motor, or a pulse motor equipped with an encoder means capable of outputting a rotational phase angle signal.

[0068] The lifting mechanism 30 is composed of multiple links. Specifically, the base end of the first link 31 is connected to the motor shaft 41 for the lifting mechanism so as to rotate together. One end of the second link 32 is rotatably connected to one end of the first link 31, and the other end of the second link 32 is rotatably connected to one end of the third link 33.

[0069] The other end of the third link 33 is connected to the sewing machine arm 21. The third link 33 is connected to the sewing machine arm 21 near the sewing needle pivot shaft 221.

[0070] The balance beam 70 moves the upper thread supplied from the thread source to the sewing needle 112 up and down. The balance beam 70 moves up and down during sewing to pull up the upper thread. Sewing becomes possible when the thread is passed through the needle eye of the sewing needle 112. The balance beam 70 is positioned near the end opposite to the end where the sewing needle 112 is located, and the balance beam drive shaft 701 that drives the balance beam 70 is on the same axis as the sewing machine swivel shaft 211. In other words, the balance beam drive shaft 701 is on the same axis as the sewing machine swivel shaft 211 and the sewing needle drive shaft 113.

[0071] As shown in Figures 4 and 5, the tatami sewing device 1 is equipped with a tatami presser foot 81. This tatami presser foot 81 moves up and down, pressing against the upper surface of the tatami mat 100 to fix it in place. The tatami presser foot 81 is configured to move up and down between the position shown by the solid line during sewing work and the position shown by the dotted line during the retracted / standby state in Figures 4 and 5.

[0072] Furthermore, the tatami sewing device 1 is equipped with a thread holding means for holding a roll of thread 90 91 for sewing the tatami mats (see Figure 10). The thread 90 is wound from the roll 91 held by the thread holding means through a thread guide 92, then through a tension roller 93, an encoder-equipped roller 94, and a tension roller 95 in that order, and then through a thread path 96, a balance beam 70, another thread path 96, and a slack-removing section 97 before being placed on a sewing needle 112.

[0073] Furthermore, since the encoder-equipped roller 94 is positioned between the tension roller 93 and the tension roller 95, the thread 90 does not loosen before or after the encoder-equipped roller 94, enabling accurate detection of rotation speed and thread usage.

[0074] As shown in Figure 7, the sewing needle 112 has a through hole 112a through which the thread 90 is inserted, and a guide groove 112b is formed axially from the sewing needle 112 through the through hole 112a to guide the thread 90 in the axial direction. As a result, the thread 90 is passed through the through hole 112a of the sewing needle 112 and positioned along the guide groove 112b in the axial direction, and the thread 90 is supplied in conjunction with the movement of the sewing needle 112.

[0075] The thread 90 attached to the sewing needle 112 becomes the upper thread. The lower thread, on the other hand, is wound onto the bobbin 27 inside the bobbin case 26 of the sewing mechanism 20.

[0076] Then, in conjunction with the oscillation of the needle arm 22, the sewing needle 112 pierces and penetrates the side of the tatami mat 100, enters the bobbin of the bobbin 26, is pulled out of the bobbin, and is withdrawn from the side of the tatami mat 100 in a reciprocating circular motion.

[0077] Furthermore, as the sewing needle 112 is pulled out of the bobbin, the lower thread is pulled up, and the sides of the tatami mat 100 are sewn together using the upper and lower threads. At this time, the tatami mat 100 is transported in direction A in Figure 1, and its sides are sewn together sequentially.

[0078] Furthermore, when the sewing needle 112 uses the thread 90, the thread 90 is supplied from the raw material 91 held by the thread holding means through the aforementioned path. When the thread 90 passes through the encoder-equipped roller 94, the encoder-equipped roller 94 rotates to calculate the amount of thread 90 used (see Figures 10 and 11).

[0079] The encoder-equipped roller 94 is connected to a control means. Specifically, the encoder-equipped roller 94 is connected to the control panel 85 shown in Figure 9. The control panel 85 has a computer installed inside, which consists of components such as I / O, CPU, ROM, RAM, SSD, and peripheral circuits (not shown), and this computer functions as the control means. The aforementioned sewing machine body 10 and the like are connected to this computer by cables.

[0080] Furthermore, the computer is not limited to being located inside the control panel 85, but may be located in another location, and the number of computers is not limited to one, but may be configured with multiple computers located in various places.

[0081] On the other hand, a sewing machine rotation detection plate is attached to the part that is linked to the reciprocating circular motion of the sewing needle 112. In this embodiment, a sewing machine rotation detection plate 264 is attached to the bevel gear 263 (see Figure 6).

[0082] Furthermore, as shown in Figures 8(a) and 8(b), the sewing machine rotation detection plate 264 is roughly disc-shaped, with a fan-shaped portion 264a extending from the outer circumference of a part of the disc so that a part of the disc extends radially.

[0083] A needle position detection sensor 265 is mounted behind the sewing machine rotation detection plate 264. When the sewing machine rotation detection plate 264 rotates in conjunction with the reciprocating circular motion of the sewing needle 112, the needle position detection sensor 265 detects the start and end positions of the fan-shaped portion 264a, thereby detecting the movement of one full rotation (one reciprocating circular motion) of the sewing needle 112.

[0084] Furthermore, the needle position detection sensor 265 is connected to the control panel 85 shown in Figure 9. The control panel 85 has a computer installed inside, which consists of components such as I / O, CPU, ROM, RAM, SSD, and peripheral circuits (not shown in the figure), and this computer functions as a control means.

[0085] As described above, the control panel 85, which is equipped with a computer, is connected to an encoder-equipped roller 94 and a needle position detection sensor 265. The reciprocating motion of the sewing needle 112 detected by the needle position detection sensor 265 and the rotation speed of the encoder-equipped roller 94 are stored in the control means of the control panel 85. The control means of the control panel 85 then calculates the cumulative amount of thread actually used by multiplying the rotation speed of the encoder-equipped roller 94 by the amount of thread used per rotation. Based on this information, a thread breakage prediction, which will be described later, is made.

[0086] [3. Method for predicting thread breakage] Next, a control method for detecting thread breakage using a thread breakage prediction means will be described. Figure 10 is a schematic side view showing a configuration including a thread breakage prediction means according to the first embodiment of the present invention. Figure 11 is a partially enlarged perspective view showing the configuration of the thread breakage detection means. Figure 12 is an explanatory diagram of the thread path for ladder stitching or zigzag stitching. Figure 13 is a diagram showing examples of warning displays and remaining amount displays on the display.

[0087] First, as shown in Figures 9, 10, and 11, the yarn breakage prediction means of this embodiment is mainly realized by an encoder-equipped roller 94 and an operation panel 85 equipped with a computer. As described above, the operation panel 85 is connected to an encoder-equipped roller 94 that detects the amount of yarn 90 used.

[0088] The thread breakage prediction means of this embodiment determines that a thread has broken if the sum of the cumulative amount of thread actually used and a predetermined predicted amount of thread used exceeds the amount of sewing machine thread remaining at the start of sewing, i.e., the initial amount of thread set. As an example of this embodiment, the predetermined predicted amount of thread used is the amount of thread used to sew one tatami mat of the maximum length. However, the predetermined predicted amount of thread used is not limited to this and may be set to a value such as 10m, 20m, or 30m, for example. A value that allows sewing to be completed without stopping midway through sewing one tatami mat is preferable.

[0089] Furthermore, the tatami sewing device 1 of this embodiment sews tatami mats using an upper thread and a lower thread, but in this embodiment, it is configured to perform thread breakage detection for either the upper thread or the lower thread. The present invention can also be configured to perform thread breakage detection for either the upper thread or the lower thread. Even with thread breakage detection for only one of the upper or lower threads, it can achieve a sufficiently greater effect compared to conventional methods.

[0090] (Upper thread breakage detection) First, let a be the initial set amount of upper thread in the raw material 91 held by the thread holding means, which is used as the upper thread of the sewing machine. In this embodiment, the raw material 91 is, for example, in an unused state, so the initial set amount of upper thread a is the amount of thread in the unused state of the raw material 91. In this embodiment, for example, the initial set amount of upper thread a can be entered as any value, such as 3000m, from the display panel of the control panel 85. However, this is not limited to this, and a configuration in which the lengths of multiple types of raw material are stored in advance and selected from is also possible.

[0091] Then, as the raw material 91 rotates and the thread is unraveled, the thread 90 is fed towards the sewing needle 112, and in the process, the tension roller 93, the encoder-equipped roller 94, and the tension roller 95 are rotated. Let e ​​be the count value of the number of rotations of the encoder-equipped roller 94 from the start of sewing.

[0092] Furthermore, if A is the amount of yarn 90 that is fed out each time the encoder-equipped roller 94 rotates, the cumulative consumption of the upper yarn is expressed by the following formula 1. c=A*e…Equation 1 (Cumulative needle thread consumption amount)

[0093] On the other hand, the predicted upper thread usage amount f is the sum of the upper thread usage amount h at the start and stop stitches when sewing the tatami mat begins, the upper thread usage amount j at the end and stop stitches when sewing the tatami mat ends, the upper thread usage k at the maximum length of the sewn section, and the distance m from the end of sewing to the cutting position of the tatami mat. Therefore, the predicted upper thread usage amount f is given by the following equation 2. Figure 12 is an example of the thread path for ladder stitching or zigzag stitching. The relationship f = h + j + k + m ... (Equation 2) holds true.

[0094] Here, if we let n be the number of times we start and stop sewing, and p be the amount of upper thread used per stop sewing, then h = n * p. Furthermore, if q is the standard amount of upper thread used per stop stitch, and Y is the ratio of the current needle height to the standard needle height, then p = q * Y. Therefore, from these equations, the amount of upper thread used h for the start and stop stitching is expressed by the following equation 3. h = n * q * Y ... Equation 3

[0095] On the other hand, if the number of stop stitches at the end of sewing is r and the amount of upper thread used per stop stitch is p, then the amount of upper thread used j for the stop stitches at the start and end of sewing is j = r * p. Also, since p = q * Y, the amount of upper thread used j for the stop stitches at the start and end of sewing is expressed by the following formula 4. j = r * q * Y … formula 4

[0096] Also, if the amount of upper thread consumed per pitch is s and the number of pitches at the maximum length is t, then the amount of upper thread used k for the sewn part is k = s * t. At the set values during operation, if the reference upper thread consumption in the sewing pitch direction is x, the reference upper thread consumption in the needle height direction is y, the current sewing pitch magnification with respect to the reference sewing pitch is X, and the current needle height magnification with respect to the reference needle height is Y, then the amount of upper thread consumed per pitch s is s = Y * y + X * x. From these formulas, the amount of upper thread used k for the sewn part is expressed by the following formula 5. k = (Y * y + X * x) * t … formula 5

[0097] And the predicted amount of upper thread used f is based on the above formula 2: f = h + j + k + m and formulas 3, 4, 5, so f = (n * q * Y) + (r * q * Y) + (Y * y + X * x) * t + m, and when this is rewritten together, the predicted amount of upper thread used f is expressed by the following formula 6. f = (n + r) * q * Y + (Y * y + X * x) * t + m … formula 6 (predicted amount of upper thread used)

[0098] Based on the initial set amount a of the upper thread of the original fabric 91, the cumulative consumption amount c of the upper thread, and the predicted amount of upper thread used f obtained as described above, a thread break determination is made. That is, when the following formula 7 is satisfied, it is determined that the upper thread has broken. This determination is made by the computer of the operation panel 85. a < f + c … formula 7

[0099] In this embodiment, a thread breakage check is performed each time a tatami mat is sewn, and if the control panel 85 determines that the above formula 7 is satisfied and a thread breakage is detected, the device is stopped, preventing the sewing of the next tatami mat from being performed. This prevents thread breakage from occurring during the sewing of the next tatami mat, and also allows for smooth thread replacement with the tatami mat removed, without having to replace the thread midway through sewing.

[0100] Furthermore, it is also possible to configure the system so that thread breakage is detected during sewing. In this case, even if the control panel 85 determines that the upper thread satisfies equation 7 during the sewing of one tatami mat and detects that the thread has broken, the device will not stop during sewing, but will stop after the sewing of one tatami mat is completed. This configuration allows for smooth thread replacement, as thread replacement can be done with the tatami mat removed, without having to replace the thread during sewing.

[0101] Furthermore, when the computer in the control panel 85 determines that the thread has broken, a warning is displayed on the control panel 85's display, and the warning light 86 at the top of the control panel flashes. Figure 13(a) shows an example of the warning display. When a warning is issued, the operator can replace the upper thread before starting the next sewing operation.

[0102] Note that the configuration in which the device is not stopped until the sewing of one tatami mat is complete is just one example of this embodiment; the device may also be stopped during sewing and a warning display may be shown. Replacing the thread is easier after sewing one tatami mat is complete, but even replacing the thread during sewing is easier than replacing it after it breaks in the conventional method, and the stitching does not become messy.

[0103] (Bottom thread breakage detection) Next, I will explain how to determine if the lower thread has broken. Simply put, lower thread breakage is determined by multiplying the amount of upper thread used by a predetermined coefficient.

[0104] Specifically, the remaining thread length b is defined as the length of the lower thread wound onto the bobbin 27 in the bobbin case 26 of the sewing mechanism 20 at the start of sewing the tatami mat. The length of the remaining thread length b is measured by the thread winding device 400 that winds the lower thread onto the bobbin, as shown in Figure 19.

[0105] In this thread winding device 400, sewing thread 410 is rotatably mounted on the right side, and the thread passes through the hole on the right side of the thread guide member 420 above, is wound onto an encoder-equipped roller 430 provided on the left side, and then wound onto the bobbin 440 below it.

[0106] Furthermore, the bobbin 440 is attached to the motor 450, and by rotating the motor 450, the sewing thread 410 is wound onto the bobbin 440 at high speed. As the sewing thread 410 is wound onto the bobbin 440, the thread rotates the encoder-equipped roller 450, and the encoder is configured to detect the rotation speed of the roller 430.

[0107] Furthermore, by multiplying the rotational speed of the encoder-equipped roller 430 by the amount of thread dispensed per rotation of the roller 430, the length of thread wound onto the bobbin 440 can be measured. The measured length of the lower thread becomes the initial set amount b of the lower thread. This thread winding device can also use the bobbin mounted on the left side as a thread holding means for the upper thread, thereby enabling the measurement of the upper thread length.

[0108] Furthermore, if we let d be the cumulative amount of lower yarn consumed, and K be the ratio of lower yarn consumption to upper yarn consumption, then the cumulative amount of lower yarn consumed is proportional to the cumulative amount of upper yarn consumed. Therefore, given the cumulative amount of upper yarn consumed c as described above, the cumulative amount of lower yarn consumed d can be expressed by the following equation 8. d=K*c…Equation 8 (Cumulative amount of bobbin thread consumption)

[0109] On one hand, let the predicted amount of the lower thread used when attaching the tatami be \(g\), and let the magnification ratio of the predicted amount of the lower thread to the upper thread be \(L\). \(L\) is, for example, in the range of \(0.3\) to \(0.5\), but it varies depending on the sewing method and tension. Since the predicted amount of the lower thread used \(g\) is proportional to the predicted amount of the upper thread used \(f\) described above, the relationship \(g = L\times f\) holds.

[0110] Since the predicted amount of the upper thread used is as shown in Equation 6 above, the predicted amount of the lower thread used \(g\) can be expressed by the following Equation 9. \(g = L\times\{(n + r)\times q\times Y+(Y\times y + X\times x)\times t + m\}\)… Equation 9 (predicted amount of the lower thread used)

[0111] Based on the initial set amount \(b\) of the lower thread, the cumulative consumption amount \(d\) of the lower thread, and the predicted amount of the lower thread used \(g\) obtained as described above, the thread break determination of the lower thread is performed. That is, when the following Equation 10 is satisfied, it is determined that the lower thread has broken. This determination is also performed by the computer of the operation panel 85. \(b\lt g + d\)… Equation 10

[0112] Similar to the case of the upper thread, the thread break determination is performed every time the sewing of one tatami is completed. Here, when the operation panel 85 determines that the above Equation 10 is satisfied and determines that the thread has broken, the device is stopped so that the sewing of the next tatami cannot be performed. This prevents the lower thread from breaking during the sewing of the next tatami, and also enables smooth thread replacement in the state where the tatami is removed without performing thread replacement during sewing.

[0113] Note that, similar to the upper thread, it is also possible to configure the thread break determination of the lower thread to be performed during sewing. In this case, when the operation panel 85 determines that the above Equation 10 is satisfied and determines that the upper thread has broken during the sewing of one tatami, the device is not stopped during sewing, but is stopped after the sewing of one tatami is completed. By configuring it in this way, thread replacement can be performed smoothly in the state where the tatami is removed without performing thread replacement during sewing.

[0114] Also, as with the upper thread, when the computer in the control panel 85 determines that the thread is broken, a warning is displayed on the display of the control panel 85, and the warning light 86 at the top of the control panel flashes. Figure 13(b) shows an example of the warning display. When a warning is issued, the operator can change the lower thread before starting the next sewing operation.

[0115] Note that the configuration in which the device is not stopped until the sewing of one tatami mat is complete is just one example of this embodiment; the device may also be stopped during sewing and a warning display may be shown. Replacing the thread is easier after sewing one tatami mat is complete, but even replacing the thread during sewing is easier than replacing it after it breaks in the conventional method, and the stitching does not become messy.

[0116] Furthermore, in the tatami sewing device 1 of this embodiment, the remaining thread amounts for both the upper and lower threads are displayed on the display panel of the control panel 85 (see Figures 13(c) and 13(d)). The remaining upper thread amount is calculated by subtracting the cumulative upper thread consumption amount f from the initial upper thread set amount a at the start of sewing. Similarly, the remaining lower thread amount is calculated by subtracting the cumulative upper thread consumption amount g from the initial lower thread set amount b at the start of sewing. Real-time upper thread amount remaining = af Real-time bobbin thread remaining amount = bg

[0117] The real-time display of the remaining thread amounts for both the upper and lower threads allows operators to keep track of the remaining thread levels, eliminating the need to wait until a thread breaks before replacing it. This enables operators to perform thread replacements while other machines are running, thus improving their work efficiency.

[0118] <Second Embodiment> Next, a second embodiment will be described. The main difference between the second embodiment and the first embodiment is the thread breakage prediction means. Specifically, the second embodiment does not have a configuration in which the encoder-equipped roller 94 rotates when the thread 90 passes through it to calculate the amount of thread 90 used. Instead, the second embodiment is equipped with an encoder that rotates in conjunction with the rotation of the bobbin to detect the amount of lower thread used.

[0119] In the following description of the second embodiment, we will focus on the differences from the first embodiment, namely the configuration of the thread breakage prediction means, and will omit explanations of similar components as appropriate.

[0120] Figure 14 is a schematic side view showing a configuration including a thread breakage prediction means according to a second embodiment of the present invention. Figure 15 is a partially enlarged perspective view showing the configuration near the bobbin of the thread breakage detection means according to the second embodiment (with the encoder-equipped disk removed). Figure 16 is an exploded view (a) of the bobbin and hook, a perspective view (b) of the bobbin and hook combined, and a side view (c) of the same according to the second embodiment. Figure 17 is a diagram showing the relationship between the hook, the upper thread and the lower thread according to the second embodiment.

[0121] As shown in Figures 14 and 15, the tatami sewing device includes a bobbin 127 inside a bobbin 126 with the bobbin thread for sewing the tatami wound around it. The coupling 128 is mounted so as to cover one end of the bobbin 127 on the winding shaft, and an encoder-equipped disk 129 is connected to the other end. In this case, the coupling 128 does not restrict the rotation of the bobbin 127, and any other joint can be used as a substitute, regardless of shape or material, as long as it is a component that transmits the rotation of the bobbin 127 to the encoder-equipped disk 129.

[0122] As shown in Figure 16(a), the bobbin case 126 is constructed by stacking the outer bobbin case 123, inner bobbin case 122, bobbin 127, and bobbin case 121 in that order from the outside. Figure 16(b) is an enlarged view of the bobbin case 126, and Figure 16(c) is a side view of the bobbin case 126, in which the outer bobbin case 123 is equipped with a pointed tip 124. There is also a gap between the outer bobbin case 123 and the inner bobbin case 122 through which the thread can pass.

[0123] The bobbin 127 has the lower thread 190 wound around it. By operating a machine that has a measuring means for measuring the amount of thread wound around the lower thread 190, the sewing thread can be wound onto the bobbin 127.

[0124] The process of sewing the tatami mat using the upper and lower threads is similar to the operation of a typical sewing machine. As shown in Figure 17, with the thread 90 (upper thread) passed through the through hole 112a (see Figure 7), when the lower part of the sewing needle 112 is inserted to a depth that allows it to go under the tatami mat 100, the thread 90 follows the guide groove 112b in the direction of sewing, and on the opposite side of the direction of sewing, a loop of thread 90a is created on the underside of the tatami mat 100 adjacent to the sewing needle 112. Thread 90 is the upper thread, and thread 190 is the lower thread.

[0125] Then, the bobbin 126 rotates, powered by the sewing mechanism motor 25. As the bobbin 126 rotates counterclockwise, the needle tip 124 is first passed through the thread loop 90a. Once passed through, the sewing needle 112 rises and leaves the tatami mat. Next, using the rotation of the bobbin 126, the thread loop 90a is passed through the part of the needle tip 124 that gradually widens, causing the loop of the thread loop 90a to expand, and the thread loop 90a passes through the gap between the inner bobbin 122 and the outer bobbin 123, and goes around the inner bobbin 122.

[0126] This movement causes the thread 90 threaded through the needle 112 to be passed through the bobbin 127, and the thread 90 is held in place by the thread 190 so that the upper thread does not come out in conjunction with the upward movement of the needle 112.

[0127] As the bobbin 126 rotates, the bobbin 123 rotates while the bobbin 122 remains stationary. After the loop of the upper thread passes through the gap to make a full circle around the bobbin 122, the bobbin 122 rotates clockwise. This rotation of the bobbin 122 quickly releases the thread 190 from the bobbin 127, which is pulled in the direction of the needle 112's movement, causing the thread 190 to create a stitch along the underside of the tatami mat.

[0128] At the same time, the thread 90 creates stitches on the upper side of the tatami mat according to the stitching pitch of the needle 112, and the sides of the tatami mat 100 are sewn together. Also, as the tatami mat 100 is conveyed in direction A in Figure 1, its sides are sewn together sequentially.

[0129] During sewing, the rotation of the bobbin 127 in conjunction with the rotation of the inner bobbin 122 causes the encoder-equipped disk 129, which is attached via the coupling 128, to rotate in sync. By detecting this rotation, the amount of lower thread used is calculated by multiplying the number of rotations by the amount of thread dispensed per rotation.

[0130] Furthermore, the encoder-equipped disk 129 is connected to a control means. Specifically, the encoder-equipped disk 129 is connected to the control panel 85, which houses a computer consisting of components such as I / O, CPU, ROM, RAM, SSD, and peripheral circuits (not shown in the diagram). This computer functions as the control means. The aforementioned sewing machine body 10 is connected to this computer by a cable.

[0131] Thus, the control panel 85, which is equipped with a computer, is connected to an encoder-equipped disk 129 and a needle position detection sensor 265. The reciprocating motion of the sewing needle 112 detected by the needle position detection sensor 265 and the rotation speed information of the encoder-equipped disk 129 are stored in the control means of the control panel 85. Therefore, the cumulative amount of thread actually used can be obtained as information. Based on this information, a thread breakage prediction means is performed.

[0132] Next, a control method for detecting thread breakage using a thread breakage prediction means will be described. As mentioned above, the control panel 85 equipped with a computer is connected to a disk 129 with an encoder that detects the amount of lower thread used by the rotation of the bobbin.

[0133] When the bobbin rotates and the lower thread is fed out, the disk 129 with an encoder also rotates in synchronization with the rotation of the bobbin, and thereby the rotation speed of the disk 129 with an encoder is detected. Then, the cumulative consumed thread amount d of the lower thread is calculated by multiplying the rotation speed of the disk 129 with an encoder by the unit thread amount of the lower thread fed out in one rotation of the bobbin, that is, one rotation of the disk 129 with an encoder. Incidentally, the initial set amount b of the lower thread and the predicted thread usage amount g of the lower thread are calculated by the same method as in the first embodiment.

[0134] Then, based on the initial set amount b of the lower thread, the predicted thread usage amount g of the lower thread, and the cumulative consumed thread amount d of the lower thread calculated as described above, a thread break determination is made, and a thread break is determined in the following cases. b < g + d... Equation 10

[0135] Thus, in the first embodiment, the actual thread usage amount of the upper thread is detected by the roller 94 with an encoder and the thread usage amount of the lower thread is calculated by multiplying this by a predetermined coefficient. However, in the second embodiment, the actual thread usage amount of the lower thread is detected and calculated by the disk 129 with an encoder.

[0136] In this case, the cumulative consumed thread amount c of the upper thread is calculated by multiplying the cumulative consumed thread amount d of the lower thread by a predetermined coefficient. If the same symbol as in the first embodiment is used for the cumulative consumed thread amount c of the upper thread, the multiplying coefficient is 1 / K. That is, the cumulative consumed thread amount c of the upper thread is calculated by the following Equation 11. c = d * 1 / K... Equation 11

[0137] Then, based on this, for the thread break determination of the upper thread as well, a thread break determination is made based on the initial set amount a of the upper thread, the predicted thread usage amount f of the upper thread, and the cumulative consumed thread amount c of the upper thread, and a thread break is determined in the following cases. a < f + c... Equation 7

[0138] Also, regarding the operation when a thread break is determined, as in the first embodiment, a warning display is shown on the display of the operation panel 85 and the warning lamp 86 at the upper part of the operation panel blinks.

[0139] In the first embodiment, the predicted amount of lower yarn used was calculated by multiplying the predicted amount of upper yarn used f by a predetermined coefficient. However, it is also possible to calculate the predicted amount of upper yarn used by first determining the predicted amount of lower yarn used and then multiplying it by the coefficient. The calculation of the predicted amount of lower yarn used is performed as follows.

[0140] The predicted amount of bobbin thread to be used, g, is the sum of the amount of bobbin thread used at the start and end of sewing when sewing the tatami mat begins, the amount of bobbin thread used at the end of sewing when sewing ends, the amount of bobbin thread used at the maximum length of the sewn section, k', and the distance m' from the end of sewing to the cutting position of the tatami mat. In this case, the predicted amount of bobbin thread to be used, g, is given by the following formula 12. The relationship g = h' + j' + k' + m' ... as shown in equation 12 holds true.

[0141] Here, the number of times stitching is started and stopped is n. ’ The amount of bobbin thread used per stop stitch is p ’ Then, h' = n'*p'. Furthermore, if q' is the standard amount of bobbin thread used per stop stitch, and Y' is the ratio of the current needle height to the standard needle height, then p' = q' * Y'. Therefore, from these formulas, the amount of bobbin thread used for the start and stop stitches is h. ’ This is expressed by the following equation 13. h ’ =n'*q'*Y'…Equation 13

[0142] On the other hand, if the number of stitches to stop at the end of sewing is r', then the amount of upper thread used per stop stitch is p', so the amount of lower thread used for the start and end of sewing stitches, j' is j' = r' * p'. Also, since p' = q' * Y', the amount of lower thread used for the start and end of sewing stitches, j ’ This is expressed by the following formula 14. j'=r'*q'*Y'…Equation 14

[0143] Also, the amount of bobbin thread consumed per pitch is s ’ If the pitch count at the maximum length is t', then the amount of bobbin thread used at the seam, k', is k' = s' * t'. At the time of operation, if x' is the standard bobbin thread consumption in the stitch pitch direction, y' is the standard bobbin thread consumption in the needle height direction, X' is the ratio of the current stitch pitch to the standard stitch pitch, and Y' is the ratio of the current needle height to the standard needle height, then the bobbin thread consumption s' per pitch is given by s' = Y'*y' + X'*x'. From these equations, the amount of bobbin thread used in the sewing area k' is expressed by the following equation 15. k'=(Y'*y'+X'*x')*t'…Equation 15

[0144] Then, the predicted amount of bobbin yarn to be used, g, is given by the above formula g = h' + j' + k' + m' ... Equation 12, and from Equations 13, 14, and 15, g = (n'*q'*Y') + (r'*q'*Y') + (Y'*y' + X'*x')*t' + m', and when this is rewritten together, the predicted amount of yarn to use for the bobbin, g, is expressed by the following equation 16. g = (n'+r')*q'*Y' + (Y'*y'+X'*x')*t' + m' ... Equation 16 (Predicted amount of yarn to use for the bobbin thread)

[0145] <Third Embodiment> Next, a third embodiment will be described. In the third embodiment, in addition to the encoder-equipped roller used in the first embodiment, two encoder-equipped disks that rotate in conjunction with the rotation of the bobbin, as used in the second embodiment, are provided as detection sensors. That is, in the tatami sewing device of the third embodiment, the actual amount of thread used is detected and calculated by the detection sensors for both the upper thread and the lower thread.

[0146] In the following description of the third embodiment, we will focus on the differences from the first and second embodiments, namely the configuration of the thread breakage prediction means, and will omit explanations of similar components as appropriate.

[0147] Figure 18 is a schematic side view showing a configuration including a thread breakage prediction means according to a third embodiment of the present invention. The thread 390 is wound in order from the raw material 391 held by the thread holding means, through the thread guide 392, onto the tension roller 393, the encoder-equipped roller 394 with an encoder, and the tension roller 395, and then passes through the thread path 96, the balance 70, the thread path 96, and the slack-removing section 97 in that order before being placed on the sewing needle 312.

[0148] When the sewing needle 312 uses the thread 390, the thread 390 is supplied from the raw material 391 held in the thread holding means through the above-described path. When the thread 390 passes through the encoder-equipped roller 394, the amount of thread 390, or upper thread, used is calculated by multiplying the number of rotations of the encoder-equipped roller 394 by the amount of thread dispensed per rotation.

[0149] Furthermore, the sewing needle 312 penetrates the side of the tatami mat 300 and enters the bobbin 327 of the bobbin 326. The sewing needle 312 is then pulled out of the bobbin 327, performing a reciprocating circular motion that pulls the sewing needle 312 out from the side of the tatami mat 300. As the bobbin 327 rotates, it supplies the lower thread wound around it, and as the sewing needle 312 is pulled out of the bobbin 327, it pulls up the lower thread, and the side of the tatami mat 300 is sewn using the upper and lower threads.

[0150] As the bobbin 327 rotates, an encoder-equipped disk 329, which is attached to the bobbin 327 via a coupling 328, also rotates. The amount of lower thread used is calculated by multiplying the number of rotations of the bobbin 327 by the amount of thread dispensed per rotation. Based on the above information on the amount of upper and lower thread used, a thread breakage prediction means is performed.

[0151] The roller 394 with an encoder and the disk 329 with an encoder attached to the bobbin 327 are connected to the control means. Specifically, the roller 394 with an encoder and the disk 329 with an encoder are connected to the operation panel 85 shown in FIG. 9. Inside the operation panel 85, a computer composed of components such as I / O, CPU, ROM, RAM, SSD, and peripheral circuits (not shown) is mounted, and this computer functions as the control means. The above-mentioned sewing machine main body 10, etc. are connected to this computer by a cable.

[0152] In this way, the operation panel 85 equipped with a computer is connected to the roller 394 with an encoder, the disk 329 with an encoder, and the needle position detection sensor 265. Information on the reciprocating motion of the sewing needle 112 by the needle position detection sensor 265, the rotational speed of the roller 394 with an encoder, and the disk 329 with an encoder is stored in the control means of the operation panel 85. As a result, for both the upper thread and the lower thread, the cumulative consumption amount of the actually used thread can be obtained as information. Based on that information, a thread break prediction is made.

[0153] The method for predicting a thread break is the same as that of the first embodiment described above for the upper thread. Based on the cumulative consumption amount c of the upper thread measured by the roller 394 with an encoder, the initial set amount a of the upper thread described above, and the predicted usage amount f of the upper thread, a thread break determination is made, and a thread break is determined in the following cases. a < f + c... Equation 7

[0154] [[ID=*]] Also, for the lower thread, it is the same as the second embodiment described above. Based on the cumulative consumption amount d of the lower thread measured by the disk 329 with an encoder, the initial set amount b of the lower thread described above, and the predicted usage amount g of the lower thread, a thread break determination is made, and a thread break is determined in the following cases. b < g + d... Equation 10

[0155] Also, regarding the operation when the upper thread or the lower thread is determined to be a thread break, similar to the first and second embodiments, a warning display is shown on the display of the operation panel 85, and the warning lamp 86 at the upper part of the operation panel blinks.

[0156] <Other Embodiments> As described above, preferred embodiments of the present invention have been explained with reference to the drawings, but various additions, modifications, or deletions are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, the configuration is such that thread breakage of either the upper thread or the lower thread can be determined, but it is also possible to have a configuration that can determine thread breakage of only one of them.

[0157] Furthermore, while an encoder is used to detect the actual amount of thread used, it is also possible to use a configuration that employs a method other than an encoder. Additionally, the predicted amount of thread used is the amount of thread used for sewing one tatami mat of maximum length, but it is also possible to use the amount of thread used for a typical tatami mat, not limited to the maximum length, and it is also possible to configure the system to set an arbitrary fixed value. [Explanation of Symbols]

[0158] 1 Tatami sewing device 10 Sewing machine body 11. Mounting platform 11A Roller 12 frames 13 Tatami mat edge supply reel 20 Sewing mechanism 21 Sewing machine arm 22 needle arms 23 Cam 24 Connecting member 25. Motor for sewing mechanism 26 Kama 27 Bobbins 30 Lifting mechanism 31. Link 1 32. Second Link 33 Third Link 40 Motor for lifting mechanism 41 Motor shaft for elevator 50 handle 51 Handle shaft 52 sprocket 60 chain 70 Balance 71 Guide roller 81 Tatami mat holder 85 Control panel 86 Warning light 90 threads 90a Thread loop 91 Original fabric 92 Threading 93 Tension Roller 94 Encoder-equipped rollers 95 Tension Roller 96 Itomichi 97 Slackening section 100 tatami mats 110 Side 112 Sewing needles 112a Through hole 112b Guide groove 113 Sewing needle drive shaft 121 Bobbin Case 122 Inner pot 123 Outer pot 124 Sword tip 126 Kama 127 bobbins 128 Coupling 129 Disks with encoders 190 Bobbin thread 211 Sewing machine pivot axis 221 Sewing needle pivot axis 251 Motor's rotating shaft 252 sprocket 261 Kama shaft 262 Rotary drive shaft 263 Bevel gear 264 Rotation detection plate 264a Sector 265 Needle position detection sensor 300 tatami mats 312 Sewing needles 326 Kama 327 bobbins 329 Disks with encoders 390 thread 391 Original fabric 392 Threading 393 Tension Roller 394 Roller with encoder 395 Tension Roller 701 Balance drive shaft

Claims

1. A tatami sewing device for sewing tatami mats together, It is equipped with a thread breakage prediction means that predicts thread breakage of the upper and / or lower sewing threads, The aforementioned thread breakage prediction means is It has a detection sensor for detecting the amount of yarn used, and a control means, The control means is The device is characterized by having a yarn breakage determination means that determines yarn breakage when the sum of the cumulative amount of yarn actually used, as measured by the detection sensor, and a predetermined predicted amount of yarn used exceeds the initial set amount of yarn. Tatami sewing device.

2. The predetermined predicted amount of yarn to be used is This is characterized by the amount of thread used to sew together one tatami mat. The tatami sewing device according to claim 1.

3. The aforementioned tatami mat is characterized by being the largest possible tatami mat. The tatami sewing device according to claim 2.

4. The aforementioned thread breakage prediction means is When the sewing machine thread is replaced, the initial thread amount and the cumulative thread consumption amount are reset, and the cumulative thread consumption amount starts counting from 0. The tatami sewing device according to claim 1.

5. If the thread breakage detection means detects a thread breakage during the sewing of a tatami mat, the sewing process is stopped after the sewing of the tatami mat is completed. Alternatively, the thread breakage detection means is configured to detect thread breakage after the sewing of the tatami mat being worked on is completed. Alternatively, the thread breakage detection means is configured to detect thread breakage between the completion of sewing the tatami mat being worked on and the start of sewing the next tatami mat. The tatami sewing device according to claim 1.

6. If the thread breakage detection means determines that the thread is broken, It further includes a notification mechanism to alert the worker when the thread breaks. The tatami sewing device according to claim 1.

7. It further includes a means for displaying the remaining amount of yarn. The tatami sewing device according to claim 1.

8. The initial set amount of the aforementioned yarn is provided with an input means that allows setting a numerical value. The tatami sewing device according to claim 1.

9. The aforementioned thread breakage prediction means predicts the breakage of the upper sewing thread. The tatami sewing device according to claims 1 to 8.

10. The detection sensor is an encoder attached to a roller through which the thread is wound. The cumulative amount of yarn consumed is calculated by multiplying the number of rotations of the roller by the amount of yarn dispensed per rotation. The tatami sewing device according to claim 9.

11. A sewing thread is installed, and a thread holding section is further provided. The roller to which the encoder is attached is Located on the path from the thread holding part to the sewing needle, and positioned between two tension members that apply tension to the sewing thread, The tatami sewing device according to claim 10.

12. The aforementioned thread breakage prediction means predicts the breakage of the lower thread sewing machine thread. The tatami sewing device according to claims 1 to 8.

13. The aforementioned sewing thread is used by winding it onto a bobbin. The detection sensor is an encoder attached to the bobbin, or an encoder attached to a disk that rotates in conjunction with the rotation of the bobbin. The cumulative amount of yarn consumed is calculated by multiplying the number of rotations of the bobbin or the disk by the amount of yarn dispensed per rotation. The tatami sewing device according to claim 12.

14. The initial thread amount is the initial thread amount measured by a measuring means that measures the amount of thread wound onto a bobbin when the sewing thread is wound onto the bobbin. The tatami sewing device according to claim 12.

15. The thread breakage prediction means predicts thread breakage of the upper and lower sewing threads, and the sewing device is capable of detecting two thread breakages: a first thread from either the upper or lower sewing thread, and a second thread from either the upper or lower sewing thread. The aforementioned thread breakage detection means is A first yarn breakage determination means determines that the first yarn has broken if the sum of the cumulative amount of yarn actually used by the first yarn, as measured by the detection sensor, and the predicted amount of yarn used by the first yarn exceeds the initial set amount of yarn for the first yarn. The device is characterized by having a second yarn breakage determination means that determines that the second yarn has broken if the sum of the cumulative amount of yarn consumed by the second yarn, calculated by multiplying the cumulative amount of yarn consumed by the first yarn by a predetermined coefficient, and the predicted amount of yarn used by the second yarn exceeds the initial set amount of yarn for the second yarn. The tatami sewing device according to claims 1 to 8.

16. The thread breakage prediction means predicts thread breakage of the upper and lower sewing threads, and the sewing device is capable of detecting two thread breakages: a first thread from either the upper or lower sewing thread, and a second thread from either the upper or lower sewing thread. The device comprises multiple detection sensors, each of which includes a first detection sensor for detecting the amount of first yarn used and a second detection sensor for detecting the amount of second yarn used. The aforementioned thread breakage detection means is A first yarn breakage determination means determines that the first yarn has broken if the sum of the cumulative amount of yarn actually used by the first yarn, as measured by the first detection sensor, and the predicted amount of yarn used by the first yarn exceeds the initial set amount of yarn for the first yarn. The device is characterized by having a second yarn breakage determination means that determines that the second yarn has broken if the sum of the cumulative amount of yarn actually used by the second yarn, as measured by the second detection sensor, and the predicted amount of yarn used by the second yarn exceeds the initial set amount of yarn for the second yarn. The tatami sewing device according to claims 1 to 8.

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