JP2006149806A - Tape cutter control device of sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the tape cutter control device of a sewing machine which can correctly cut a tape at a target position even when the tape is over-sewn on a sewn object consisting of a perforated material, a mesh-like material, etc. <P>SOLUTION: The tape cutter control device comprises a sensor 22 which detects existence of the sewn object, a stitch number counter 26 which initiates counting of the number of stitches by the signal of the sensor, and a cloth end distinction means driven with the timing when the number of stitches counted by the counter agrees with the target number of stitches and discriminating whether or not continuation length until a cloth detection signal varies after starting counting of the stitch number counter about a tape cutter for cutting the tape sewn on the sewn object at a downstream side in the cloth feed direction from a needle location is beyond a considered cloth end effective distinction value, and a driving stitch number counter is reset when the continuation length of the cloth detection signal is determined to be less than the cloth end effective distinction value based on the distinction results of the cloth end distinction means and count action by the driving stitch number counter is continued when the continuation length of the detection signal is determined to be beyond the cloth end effective distinction value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is capable of realizing a stable cutter operation even when sewing a tape on a sewing tape tape control device, in particular, a sewing material made of a material having a hole or a mesh-like material. The present invention relates to a tape cutter control device for a sewing machine.

  Conventionally, after sewing in the longitudinal direction of the tape in a state where a tape such as a long cloth is overlapped on a material to be sewn (hereinafter also referred to as cloth), the tape protruding from the cloth edge is removed from the cloth edge. Cutting is automatically performed at a predetermined length, and a sewing machine equipped with a tape cutter is used for that purpose (see, for example, Patent Document 1).

  FIG. 10 shows an outline of an example of a tape cutter control device provided in such a sewing machine.

  This tape cutter control device moves a tape cutter (not shown) installed in the vicinity of the needle position of the sewing machine at a predetermined timing by a drive signal output from a control unit (CPU) 110 that controls the entire sewing machine. By driving, the tape is cut at a target position.

  The needle position detector 120 detects a needle position signal as the sewing machine main shaft rotates, and the needle position signal is input to the CPU 110.

  In addition, near the needle position of the sewing machine, the cloth end (front end / rear end) sent to the needle position during sewing is detected based on a signal change (cloth end detection signal) corresponding to the presence or absence of the cloth (sewing material). The photo sensor 122 is installed, and an output signal from the sensor 122 is input to the CPU 110 via the cloth edge detection circuit and the I / O interface.

  Further, the tape cutter control device includes a signal (needle) detected by the needle position detector 120 until the tape cutter is driven after the cloth edge is detected based on a signal change output from the sensor 122. The counter circuit 126 for starting the counting operation is provided.

  Further, the CPU 110 compares the number of stitches (count value) output from the counter circuit 126 with the target number of stitches set in advance by the sewing start setting switch 128 or the sewing end stitch number setting switch 130, and the target stitch number. And the count value of the counter circuit 126 coincide with each other, a CPU 110 outputs a cutter driving signal to the solenoid 111 via the drive circuit 137, and the tape is cut.

  By performing the tape cutter operation as described above, both the front end side and the rear end side can be cut from the cloth end to an appropriate tape length.

Japanese Patent Publication No. 7-38911

  However, in the tape cutter control device, there is a part where a signal indicating no cloth is detected by a sensor at a part other than the cloth edge, such as a material having a design-like hole or a mesh-like material. When sewing tape on the workpiece to be sewn, design holes and mesh portions are detected by sensors, and the number of stitches is counted from there. Therefore, not only the tape but also the material is cut by mistake. There was a problem that.

  In such a case, it is determined whether or not the duration from the first signal change of the sensor to the next change is greater than or equal to a predetermined length. When the counting is started and the length is less than the predetermined length, it is easily considered that the occurrence of the above problem is prevented by not counting. However, in such a configuration, there is always a time delay for determining the duration of the sensor signal from when there is a change in the signal of the sensor until the count starts, and in tape cutting at the front end of the cloth, The tape is cut at a position closer to the sewing product than the set number of stitches, and the tape is cut at a position farther from the sewing product than the set number of stitches when cutting the tape at the rear end of the fabric. There is a problem that the tape cannot be cut.

  The present invention has been made to solve the above-described conventional problems, and even when a sewing is performed by overlaying a tape on a design-like hole or a sewing product having a mesh-like portion, the end portion of the sewing product is attached. It is an object of the present invention to provide a tape cutter control device that can accurately detect, prevent the workpiece from being cut accidentally when cutting the tape, and cut the tape accurately at a set position. To do.

  The present invention is a sensor that is arranged in the vicinity of a needle position, and outputs a cloth detection signal according to the presence or absence of the workpiece to be fed to the needle position when the workpiece to which the tape is overlapped is fed to the needle position for sewing. And a driving needle number counter that starts counting the number of stitches based on a change in the cloth detection signal output from the sensor, and a timing at which the number of stitches counted by the counter matches the target stitch number. In a tape cutter control device for a sewing machine, comprising: a tape cutter for cutting a tape sewn on a workpiece to be downstream of the needle position in the cloth feeding direction; the drive needle number counter based on a change in the cloth detection signal A cloth edge determining means for determining whether or not a length of time until the cloth detection signal changes next is equal to or greater than a predetermined cloth edge effective determination value. Based on the above, if it is determined that the cloth detection signal has a duration of less than the cloth edge valid determination value, the driving needle number counter is reset, and the detection signal has a duration of not less than the cloth edge valid determination value. If it is determined that the above problem is solved, the counting operation by the driving needle counter is continued.

  According to the present invention, the end of the workpiece is detected based on the cloth detection signal corresponding to the signal change caused by the presence or absence of the material detected by the sensor, and the cloth detection signal when the end is detected is detected. If the continuous length is determined and the continuous length is less than the predetermined cloth edge valid determination value, the counter of the number of drive needles for driving the tape cutter is reset, and conversely, the continuous length is effective at the cloth edge. Since counting is continued when the value is greater than or equal to the discriminant value, it is possible to prevent detection of holes or meshes that output detection signals less than the fabric edge discriminating value as fabric end parts. ) Can be detected accurately, and the workpiece can be prevented from being accidentally cut when cutting the tape, and the tape can be cut accurately at the set position.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an outline of a tape cutter control device for a sewing machine according to an embodiment of the present invention. The tape cutter control device of the present embodiment controls the entire sewing machine based on a program stored in the ROM 8, and controls to drive the tape cutter 12 installed in the vicinity of the needle position of the sewing machine at a predetermined timing. A section (CPU) 10 is provided, and the tape is cut at a target position by a drive signal output from the control section 10.

  When a rotation command signal is input by a pedal sensor 14 that detects the depression amount of a pedal instructing the rotation speed of the sewing machine and converts it into an electric signal, the control unit 10 turns the motor 18 that rotates the sewing machine spindle into a motor encoder. Based on the encoder signal output from 6, the normal sewing operation is controlled by outputting a signal for rotating at a rotational speed corresponding to the depression amount. The rotation of the main spindle of the sewing machine by the motor 18 is detected as the number of stitches at the time of sewing by the needle position detector 20, and this detection signal is input to the control unit 10.

  Also, in the vicinity of the needle position of the sewing machine, when the workpiece with the tape overlapped is sent to the needle position and sewing is performed, the cloth sent to the needle position during sewing is detected, and the workpiece to be sent to the needle position is detected. A sensor 22 that outputs a cloth detection signal corresponding to the presence or absence of the cloth is installed and input to the control unit 10.

  Further, the tape cutter control device includes a signal (number of stitches) detected by the detector 20 until the tape cutter 12 is driven after the cloth end is detected based on a signal change output from the sensor 22. ) And a reset signal for resetting the count value of the counter 26 is input from the control unit 10 to the counter 26. The

  Further, a sewing start stitch number setting unit 28 and a sewing end stitch number setting unit 30 for setting the number of stitches (count value N) output from the counter 26 and target stitch numbers S and E for comparison are respectively provided. It is installed on an operation panel (not shown), and setting signals of both setting devices are input to the control unit 10 respectively. The sewing start setting device 28 is a setting device for setting the cutting position of the tape at the front end of the sewing product as the number S of sewing needles from when the front end of the sewing product is detected until the tape cutter 12 cuts the tape. The sewing end setting device 30 sets the cutting position of the tape at the rear end of the sewing product as the number E of sewing needles from when the rear end of the sewing product is detected until the tape cutter 12 cuts the tape. It is a setter.

  The control unit 10 compares the target number of stitches set by the sewing start stitch number setting device 28 or the sewing end stitch number setting device 30 with the number of stitches counted by the drive stitch number counter 26, and the target stitches are compared. When the number matches the count value, a drive signal is output to the rotary solenoid 58 (see FIGS. 2 to 4) for driving the tape cutter via the cutter drive circuit 24, the tape cutter 12 is driven, and the tape Disconnection is performed.

  Furthermore, the tape cutter control device of the present embodiment sets the sewing end effective edge determination value as a cloth edge effective determination value setting means for determining the continuous length of the cloth detection signal input from the sensor 22. The machine 38 and the cloth end effective discrimination value setting unit 40 at the end of sewing are installed on an operation panel (not shown), and these setting signals are input to the control unit 10. Although details will be described later, the sewing start effective edge determination value J and the sewing end effective edge determination value J for detecting the front edge of the cloth by means of the sewing start cloth edge effective determination value setting unit 38 and the sewing end cloth edge effective determination value setting unit 40. An end cloth edge valid discrimination value K is set.

  In FIG. 2, the principal part of the sewing machine provided with the tape cutter control apparatus of this embodiment is shown.

  In this sewing machine, a cloth C placed on the sewing machine bed 52 and a tape T superimposed thereon are guided by a cloth guide 54 by a needle 32 that can be moved up and down of the sewing head 50, and a well-known (not shown). The tape is fed in the length direction of the tape T indicated by the arrow F by the feed dog, and sewing is performed by the vertical movement of the needle 32.

  In the vicinity of the side of the needle 32, a cloth detection sensor 22 that detects the front end and the rear end (cloth end) of the cloth C is attached to an attachment plate 56. The sensor 22 is a reflection type having a light projecting unit and a light receiving unit at the center, and the reflected light reflected by the reflecting plate 53 attached on the sewing machine bed 52 below the sensor 22 is received by the light receiving unit. The presence or absence of the cloth is detected depending on whether or not it is detected.

  A tape cutter 12 is disposed downstream of the position of the needle 32 in the cloth feeding direction, and the tape T is cut by driving the cutter 12 with a rotary solenoid 58.

  6A and 6B schematically show the positional relationship in the planar direction of the cloth C, the tape T, the tape cutter 12, the sensor 22, and the needle 32 on the front end side and the rear end side of the cloth. . This figure shows an image in which the tape T is overlapped on the cloth C moving forward in the sewing direction indicated by the arrow (upward in the figure) and the tape is sewed in the longitudinal direction by the needle 32 indicated by a circle. There is a sensor 22 on the left side in the vicinity of the needle 32, and a cutter 12 is installed in front of the needle 32. For convenience, the front side of the tape T is omitted and shown in a short form. Actually, however, the tape T is supplied from a tape reel (not shown) installed above the sewing machine before cutting and has a continuous shape. ing.

  The tape cutter (unit) 12 has a lower fixed knife 60 and an upper moving knife 62 as shown in an enlarged perspective view in FIG. 3 and a front view of the main part in FIG. The knife 62 is fixed to the tip end portion of a cutter arm 66 that can swing around a support shaft 64 with a screw 60A.

  Further, a screw 68A at the tip of the link 68 screwed to the rotary shaft of the rotary solenoid 58 is movably engaged with the long hole 66A at the rear end of the cutter arm 66. When the rotary arm 58 rotates the cutter arm 66 together with the link 68 in the direction of the arrow W in the figure, the moving knife 62 in the moving knife cover 70 is driven in the closing direction, and the cloth guide 54 and the tape guide 72 are moved. The tape T sewn on the cloth C to be guided is cut. When the rotation of the solenoid 58 is released, the moving knife 62 returns to the initial position shown in FIG. 4 by the spring 74 connected to the link 68. 4 denotes an arm stopper that restricts the movement of the cutter arm 66.

  The tape cutting operation by the tape cutter control device having the above configuration will be described below with reference to the timing chart of FIG. 5 and the flowcharts of FIGS. In addition, the number described at the left end of the timing chart is a code of an element that outputs a corresponding signal.

  However, in this example, as shown in FIGS. 6A and 6B, holes H1 and H2 having a hole diameter equivalent to 0.5 stitches are formed in the cloth C, and the sewing start stitch number setting device 28 is provided. The target number of stitches S on the cloth front end side set by S is 3 stitches (S = 3), and the target number of stitches E on the cloth rear end side set by the sewing end stitch number setting unit 30 is 5 stitches (E = 5). The stitch start effective edge determination value J set by the sewing start cloth edge effective determination value setter 38 is set to 0 stitch (J = 0) and the sewing end cloth edge effective determination value setter 40 is set. It is assumed that the cloth end effective discrimination value K at the end of sewing is set to one stitch (K = 1).

  First, when power is supplied to the tape cutter control device, in step S1, a reset signal is output from the control unit 10 to the drive needle counter 26 at the timing t0, and the drive needle counter 26 is reset (initialized). The

  Further, in this step S1, the above-described target stitch numbers S and E, the sewing start cloth end effective determination value J, and the sewing end cloth end effective determination value K are read by the control unit 10.

  Next, the process proceeds to step S2, where it is determined whether or not a sewing machine rotation command has been input to the control unit 10 by the pedal sensor 14 in response to the depression of the pedal. , The motor drive command signal is output from the control unit 10 to the motor 18 via the motor drive circuit 16 at the timing t1, the motor 18 is started, and the sewing machine main shaft starts rotating.

  Next, the process proceeds to step S4, where the cloth edge determination process is started. As shown in detail in FIG. 8, in the cloth edge determination fetching process, first, in step S12, it is determined based on the logical value of the cloth detection signal whether or not the cloth detection signal output from the sensor 22 has changed. The Here, when the motor 18 is started in step S3, the cloth C is fed into the needle 32, and the front end C1 of the cloth C on which the tape T is stacked reaches the lower side of the sensor 22 as shown in FIG. Then, in step S12, it is determined that the cloth edge detection signal has changed at the timing t2, and the process proceeds to step S13.

  In step S13, a count start signal is output from the control unit 10 to the drive needle number counter 26, and the count operation of the needle position signal is started by the drive needle number counter 26. Then, the process proceeds to step S14.

  In step S14, based on the logical value of the cloth detection signal, whether the change in the cloth detection signal output from the sensor 22 is a change indicating that the cloth is present or not is a change indicating that the cloth is present or not. It is judged by.

  Here, since the cloth detection signal changes from the absence of cloth to the presence of cloth at the timing t2 when the front end C1 of the cloth C reaches below the sensor 22, an affirmative determination is made in step S14 and the process proceeds to step S15. To do.

  In step S15, it is determined whether or not the count value N counted by the drive needle number counter 26 is equal to or greater than the sewing start cloth edge effective determination value J. Here, the cloth end effective discrimination value J at the start of sewing is set to 0 stitch (J = 0), and the count value N of the drive stitch counter 26 is 0 (N = 0) immediately after the count starts, so step S15. 7, it is determined that the count value N is equal to or greater than the cloth edge effective determination value J at the start of sewing (N = J), and this cloth edge determination process is terminated while continuing the counting operation by the driving needle number counter 26 to complete the step of FIG. The process proceeds to S5. As described above, by the process of step S15, after the count operation of the driving needle number counter 26 based on the change of the cloth detection signal in step S12, the duration until the cloth detection signal changes next is increased. Then, it is determined whether or not a predetermined sewing start cloth edge effective determination value (J) is exceeded.

  In step S5, determination is made until the count value N counted by the drive stitch number counter 26 matches the target stitch number S (here, S = 3) on the cloth front end side set by the stitch start stitch number setting unit 28. When it is determined that they coincide with each other at the timing t3 (YES in step S5), the process proceeds to step S6, and the drive signal is sent from the control unit 10 to the rotary solenoid 58 via the cutter drive circuit 24 for a predetermined time. The tape cutter 12 is output and the tape on the cloth front end side is cut. FIG. 6A shows a state in which the front end C1 of the cloth C is detected by the sensor 22. Thereafter, the front end C1 of the cloth C moves in the direction of the tape cutter 12 by three stitches. When the position C2 shown in (A) is reached, the tape cutter 12 is driven.

  Further, the process shifts to step S8 and the process shifts again to the cloth edge determination process shown in FIG. 8, and the change of the cloth detection signal is detected again in step S12.

  When the cloth C is further fed and the logical value of the cloth detection signal of the sensor 22 is changed by the hole H1 at timing t4, an affirmative determination is made in step S12, and the process proceeds to step S13, as in step S4. The count operation by the drive needle number counter 26 is started by the command of 10. Further, in step S14, whether the change in the cloth detection signal detected in step S12 is a change indicating the presence of cloth or no change is controlled based on the logical value of the cloth detection signal. Determined by the unit 10.

  In the timing chart of FIG. 5, the cloth detection signal is omitted from t3 to t4 because there is no change.

  At the timing t4, since the hole H1 is detected and the cloth detection signal changes from the presence of cloth to the absence of cloth, a negative determination is made in step S14, and the process proceeds to step S16. Then, after the start of the counting operation of the drive needle number counter 26 based on the change of the cloth detection signal in step 12, the count value N counted by the drive needle number counter 26 is equal to or greater than the cloth end effective determination value K at the end of sewing. Judgment is made. Here, since K = 1 is set, immediately after the change in the cloth inspection signal is detected in step S12, the count value N is 0, so a negative determination is first made and the process proceeds to step S17.

  In step S17, it is determined whether or not the cloth detection signal has changed again after the change of the cloth detection signal is detected in step S12. In step S17, since there is no change in the cloth detection signal between t4 and t5, a negative determination is made, the process returns to step S16, and the negative processing in steps S16 and S17 is repeated.

  Here, when the hole H1 passes below the sensor 22 at the timing of t5, the cloth detection signal changes from absence of cloth to presence of cloth, so an affirmative determination is made in step S17, and the routine proceeds to step S18.

  In step S18, a reset signal is sent from the control unit 10 to the drive needle number counter 26 to initialize the count value of the drive needle number counter 26, and the count operation by the drive needle number counter 26 is stopped. Shifting to S12, the change of the cloth detection signal is monitored again.

  That is, when the hole H1 is detected by the sensor 22, the cloths are subsequently counted after the count operation of the drive needle number counter 26 based on the change of the cloth detection signal in Step 12 by the processing of Steps S17 and S18. Number of driving needles started when it is determined that the length of time until the detection signal changes is less than the cloth edge effective determination value K at the end of sewing, and the cloth detection signal changes from the presence of cloth to the absence of cloth by the hole H1. The counting operation of the counter 26 is interrupted.

  By the processing of Steps S12 to S14 and Steps S16 to S18 at the timing from t4 to t5, a hole H1 having a diameter (0.5 stitches) smaller than the cloth end effective discrimination value K (1 stitch) at the end of sewing is detected by the sensor 22. When detected, the control unit 10 prevents the cutter 12 from malfunctioning by erroneously determining the hole H1 as the cloth rear end.

  As shown in FIGS. 6A and 6B, since the cloth C has another hole H2, when the sensor 22 detects the hole H2, the same processing as the hole H1 described above is repeated. In the timing chart of FIG. 5, the processing section for the hole H <b> 2 is omitted in the timing chart of FIG. 5.

  When the sewing further progresses and the trailing end C3 of the fabric C reaches below the sensor 22, an affirmative determination is made in step S12 at the timing t6, the process proceeds to step S13, and the counting operation by the driving needle number counter 26 is started again. The

  Next, the process proceeds to step S14, and it is determined whether or not the change in the cloth detection signal in step S12 is a change indicating the presence of cloth to the presence of cloth. Here, since the cloth rear end C3 has reached below the sensor 22, the detection signal changes from the presence of cloth to the absence of cloth. Therefore, a negative determination is made in step S14, and the process proceeds to step S16.

  In step S16, it is determined whether or not the count value N counted by the drive needle number counter 26 is equal to or greater than the cloth edge valid determination value K (K = 1), but the trailing edge C3 of the cloth C is below the sensor 22. Since the count value N of the drive needle number counter 26 is still 0 immediately after reaching, a negative determination is made in step S16 and the routine proceeds to step S17.

  In step S17, it is detected whether there is a change in the cloth detection signal. Since the hole H1 and the hole H2 have already passed under the sensor 22, here, a change in the cloth detection signal is not detected, a negative determination is made, the process returns to step S16, and until it reaches t7, step S16 is reached. And the negative judgment of step S17 is repeated.

  Thereafter, when the cloth C is further fed and reaches t7, the needle position signal is counted by the drive needle number counter 26, and the count value N becomes 1. Then, in step S17, it is determined that the count value N is equal to or greater than the cloth edge effective determination value K (K = 1) at the end of sewing (YES in step S16), and the cloth needle counter 26 continues the count operation while the count operation is continued. The edge determination process is terminated, and the process proceeds to step S9 in FIG.

  As described above, after the start of the counting of the drive needle counter 26 based on the change of the cloth detection signal in Step 12 by the processing of Step S16 and Step S17, It is determined whether or not the continuous length until the cloth detection signal changes is equal to or greater than a predetermined sewing end effective edge determination value (K). The processing of step S16 and step S17 performed by the control unit 10 is the cloth edge determination means of the present invention.

  Then, in step S9, until the count value N counted by the drive needle number counter 26 coincides with the target stitch number E (here, E = 5) set on the cloth front end side by the stitch number setting unit 28 at the end of sewing. If the determination is made and it is determined that they coincide with each other at the timing of t8 (YES in step S9), the process proceeds to step S10, and a drive signal is sent from the control unit 10 to the rotary solenoid 58 via the cutter drive circuit 24. The time is output, the tape cutter 12 is driven, the tape on the trailing edge side of the cloth is cut, and a series of processing is completed.

  FIG. 6B shows a state in which the tape cutter 12 cuts the tape in the state in which five stitches are stitched according to the target number of stitches after the rear end C3 of the cloth C is detected by the sensor 22 by the above processing. Is shown.

  Note that the timing chart shown in FIG. 5 shows an example in which the front end of the cloth C has no fluff or edge decoration, and the front end of the cloth C may be determined using the detection signal of the sensor 22 as it is. However, as shown in FIG. 9, when there is a fluff or edge decoration at the tip of the cloth C, the cloth edge effective determination value J may be set to a number other than 0 (for example, J = 1).

  That is, in the cloth edge determination process in step S4, if the cloth detection signal changes due to the fluff or edge decoration on the cloth front edge side, the process proceeds to steps S12, 13, 14, and 15, and a negative determination is made in step S15 and the process proceeds to step S19. When the count value N of the drive needle number counter 26 is less than the cloth edge effective determination value J (J = 1) at the start of sewing, and the change of the cloth detection signal is detected, the drive needle number counter 26 is set. It can be reset, and the tape cutting operation at the front edge of the cloth can be accurately detected as in the case where the cloth C has holes or mesh-like parts, and the tape cutter is erroneously detected. Thus, it is possible to prevent the workpiece from being cut.

  In this case, after the start of counting of the driving needle number counter 26 based on the change of the cloth detection signal in step 12 by the processing of step S15 and step S19, the number of stitches sewn during this time is counted, and then the cloth is counted. It is determined whether or not the continuous length until the detection signal changes is equal to or greater than a predetermined sewing start cloth edge effective determination value (J). In other words, the processing at step S15 and step S19 is also the cloth edge determination means of the present invention.

  As described above, in the present invention, based on the determination result of the cloth edge determination means that is executed by the processing of Steps S15 to S16 and Step S19, it is determined that the continuous length of the cloth detection signal is less than the cloth edge effective determination value. Control when the control unit 10 resets the driving needle number counter 26 in steps S18 and S20, and when the duration of the detection signal is determined to be greater than or equal to the cloth edge valid determination value. The processing of step S15 and step S16 for continuing the counting operation by the driving needle number counter 26 executed by the unit 10 is the control means of the present invention.

  According to the embodiment described above in detail, as shown in FIG. 6B, even when the tape T is sewn on the cloth C having the plurality of holes H1 and H2, the front end side and the rear end side of the cloth are As in the case where there is no hole, the tape T can be accurately cut at the target position.

  In addition, even when the tape is sewn on a cloth having fluff or edge decoration on the front end side of the cloth as shown in FIG. 9, the tape T can be accurately cut at the target position.

  Furthermore, the tape cutter control device according to the present embodiment starts counting the number of stitches when a change in the fabric detection signal is detected. Therefore, if the fabric detection signal does not change more than a predetermined length, the count of the number of stitches is counted. Compared to the case of starting, there is no time delay for confirming the change of the cloth detection signal, the number of stitches from the edge of the cloth can always be counted accurately, and the tape is accurately positioned with respect to the sewing product. Can be cut off.

  In the above-described embodiment, in step S16 and step S19, the needle position signal after the drive needle number counter 26 starts counting is counted, and the count value of the drive needle number counter 26 is started at the start of sewing. Compared with the discriminant value (J) or the cloth end effective discriminant value (K) at the end of sewing, the duration of the fabric detection signal is judged. From the motor encoder 6 attached to the motor 18 for rotating the sewing machine main shaft. An encoder counter for counting the output encoder signal is provided separately from the driving needle number counter 26, and the counting operation by this encoder counter is started together with the start of the counting of the driving needle number counter 26 in step S13. In steps S15 and S16, The count value of this encoder counter and the material edge effective discrimination value (J) at the start of sewing Or, compared with the cloth edge effective determination value (K) at the end of sewing, the encoder counter is reset together with the driving needle number counter 26 in step S18 and step S20, and the duration of the cloth detection signal is determined. good.

  Moreover, although the case where the cloth was formed with holes has been described in the above embodiment, the present invention can also be applied to a case where the material is a mesh-like material.

The block diagram which shows the outline | summary of the tape cutter control apparatus of one Embodiment which concerns on this invention Partial perspective view showing relationship between tape cutter and sewing machine constituting tape cutter control device The perspective view which expands and shows the said tape cutter The front view which expands and shows the principal part of the said tape cutter Timing chart showing control operation of tape cutter according to this embodiment Schematic showing the characteristics of the tape cutting operation according to this embodiment The flowchart which shows the control operation of the tape cutter by this embodiment The flowchart which shows the characteristic of the control operation of the tape cutter by this embodiment Schematic showing fuzz of cloth Block diagram showing the outline of a conventional tape cutter control device

Explanation of symbols

10: Control unit (CPU)
DESCRIPTION OF SYMBOLS 12 ... Tape cutter 14 ... Pedal sensor 16 ... Motor drive circuit 18 ... Motor 20 ... Needle position detector 22 ... Cloth detection sensor 24 ... Cutter drive circuit 26 ... Drive needle number counter 28 ... Sewing start stitch number setting device 30 ... End of sewing Needle number setter 32 ... Needle 38 ... Start of sewing cloth edge effective discrimination value setter 40 ... End of sewing cloth edge effective discrimination value setter C ... Cloth T ... Tape

Claims (2)

A sensor that is arranged in the vicinity of the needle position, and outputs a cloth detection signal according to the presence or absence of the sewing object to be fed to the needle position when the sewing object on which the tape is overlapped is sent to the needle position for sewing.
A drive needle counter that starts counting the number of stitches based on a change in the cloth detection signal output by the sensor;
The sewing machine is provided with a tape cutter that is driven at the timing when the number of stitches counted by the counter coincides with the target number of stitches, and that cuts the tape sewn on the workpiece on the downstream side in the cloth feeding direction from the needle position. In the tape cutter control device,
A cloth edge determination for determining whether or not a continuous length until the cloth detection signal changes after the start of counting of the driving needle number counter based on the change of the cloth detection signal is equal to or greater than a predetermined cloth edge effective determination value. With means,
Based on the determination result of the cloth edge determination means, if the continuous length of the cloth detection signal is determined to be less than the cloth edge valid determination value, the drive needle number counter is reset, and the detection signal has a continuous length. Is determined to be equal to or greater than the cloth edge valid determination value, the count operation by the drive needle number counter is continued.   2. The sewing machine tape cutter control device according to claim 1, further comprising a cloth edge effective determination value setting means for setting the predetermined cloth edge effective determination value.

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