DE112017008004B4 - sewing machine - Google Patents

Abstract

A sewing machine (100) comprising: a looper (132) which links an upper thread (T, T ') and a lower thread (Td, Td') together by engaging the thread through a needle eye (131a, 131a ') of a sewing needle ( 131, 131 ') catches the upper thread (T, T'); a thread lever (133) which has a small hole (113a) through which the upper thread (T, T ') is guided and which holds the upper thread (T, T ') lifts from a sewing material (Ob, Ob'), which is an object to be sewn, by lifting the small hole (113a) from a lower turning point to an upper turning point; a central foot (135, 135 '), which prevents the sewing material (Ob, Ob') from being lifted; a drive source (136) which drives the central foot (135, 135 '); a transport unit (P1) which transports the sewing material (Ob, Ob'); anda tension monitoring unit (1A3c) which monitors an upper thread tension on the basis of a force exerted by the upper thread (T, T ') on the central foot (135, 135') by the central foot (135, 135 ') during transport of the sewing material (Ob, Ob ') is brought into contact with the upper thread (T, T') by the transport unit (P1).

Description

TECHNICAL AREA

The present invention relates to a sewing machine with a central foot which presses on a material to be sewn during sewing.

STATE OF THE ART

In the prior art, an upper thread of a sewing machine is guided along a thread guide path, with a supply source such as a bobbin attached to an arm section or a stand serving as a starting point and a sewing needle, which is a removal point for the upper thread, serving as an end point.

Patent Document 1 illustrates an upper thread tension detector which detects an upper thread tension during a sewing operation by means of a piezoelectric element arranged in the thread guide path described above. Further, Patent Document 1 describes a sewing machine in which a piezoelectric element is arranged at a position where the piezoelectric element can be brought into contact with the upper thread, and a thread breakage is detected through the contact of the upper thread with the piezoelectric element. In Patent Document 2, an automatic thread tensioning sewing machine is disclosed in which a strain gauge is arranged in the thread guide path described above, the tension curves of the upper thread relative to the rotational phase of the sewing machine main shaft are calculated on the basis of the output signal thereof, and the upper thread tension is set according to the tension waveforms.

Patent Documents 3 and 4 show a sewing machine which not only detects an upper thread tension but also controls the upper thread tension in accordance with a sewing pattern using an upper thread tension adjusting device or an upper thread tension unit. Specifically, an upper thread tension adjusting device is explained in Patent Document 3, whereby the resistance force of the upper thread passed between a fixed plate and a thread pressure plate can be changed with the aid of a pressing force applied by an electromagnetic actuator or a torque applied by an electromagnetic actuator during a sewing process. Patent document 4 discloses a sewing machine which has a thread tension unit for optimally setting a thread tension even when the seam width and direction are constantly changing in order to produce an embroidery with a good texture. Further, Patent Documents 3 and 4 describe a configuration of a control for adjusting the thread tension based on the output of an upper thread tension detector (a tension detection unit in Patent Document 4) that detects the thread tension using a piezoelectric element or a detection coil.

In addition, a sewing machine is disclosed in Patent Document 5, which has a separate motor for driving each machine element such as a needle bar, a thread lever and a presser foot and which adjusts an upper thread tension based on predetermined torque data and one of the motor in accordance with a Angle of rotation of the motor driving the thread lever controls the current value to be supplied.

Furthermore, in the vicinity of the end point of the thread guide path described above, a sewing material pressure device, which is generally referred to as a sewing foot or central foot, is attached in order to prevent the sewing material from being lifted up when the sewing needle is raised. Patent Document 6 discloses a sewing machine in which the pressing accuracy of a fabric is improved by controlling the driving force of a motor driving the pressing device. In Patent Document 7, a sewing machine is disclosed which detects the thickness or hardness of a sewing material on the basis of detected rotational angle values or drive torque values of a motor driving a central foot.

Patent Documents 1 to 5 thus disclose a sewing machine which, in order to improve sewing quality, has a device for detecting or controlling an upper thread tension during sewing such as a thread breakage or a thread tension caused by the upper thread tension. Further, in Patent Documents 6 and 7, a sewing machine is disclosed which changes a functional scheme of the presser in order to improve sewing quality such as the tightening accuracy caused by the pressing accuracy of the sewing material by the pressing device.

LIST OF QUOTES

PATENT LITERATURE

• Patent Document 1: Japanese Patent Application Laid-Open No. JP H06 - 343 784 A
• Patent Document 2: Japanese Patent Laid-Open No. JP H07-662 A
• Patent Document 3: Japanese Patent Laid-Open No. JP H11-47,479 A
• Patent Document 4: Japanese Patent Laid-Open No. JP H07-661 A
• Patent Document 5: Japanese Patent Application Laid-Open No. JP 2010 - 178 785 A
• Patent Document 6: Japanese Patent Application Laid-Open No. JP H11-19358 A
• Patent Document 7: Japanese Patent Application Laid-Open No. JP 2010 - 131 175 A

The German Offenlegungsschrift DE 10 2008 051 617 A1 discloses a thread tension control device of a sewing machine. The thread tension control device comprises thread tension discs which wind up a thread and a pulse motor, the thread tension discs being connected to the pulse motor via a motor output shaft. A phase difference that occurs when the motor output shaft of the pulse motor rotates is detected and used to set the thread tension.

BRIEF DESCRIPTION OF THE INVENTION

TECHNICAL PROBLEM POSITION

In the sewing machines disclosed in Patent Documents 1 to 4, detection of an upper thread tension always leads to an increase in the manufacturing cost of the sewing machine because it requires a thread tension detecting device or an assembling tool therefor and a circuit equipped with a piezoelectric element, a strain gauge or the like. In addition, the maintenance costs of the sewing machine increase because the detector has to be recalibrated due to changes in its sensitivity or bandwidth over time. Furthermore, the arrangement of the detector in the thread guiding path results in restrictions for the structural design, for example an extension of the thread guiding path or the provision of an installation space, which lead to a restriction in the design of a sewing machine head. In addition, the sewing machine disclosed in Patent Document 5 must be equipped with a motor for individually driving the thread take-up lever. In brief, the sewing machines of the prior art disclosed in Patent Documents 1 to 5 may have many components to be added to the sewing mechanism for detecting the upper thread tension, which leads to a problematic increase in cost and constructional limitations.

On the other hand, the sewing machines disclosed in Patent Documents 6 and 7 can improve sewing quality such as the tightening accuracy described above, since the pressing accuracy of the sewing material is improved by changing the functional scheme of the pressing device. Since the behavior of the upper thread, i. H. the supply amount, tension and the like of the upper thread, however, is not monitored, no seam is formed in the event of a thread breakage, for example, whereby the sewing work becomes faulty. In addition, the sewing process is continued even if the thread tension or the texture is disturbed by external influences. In order to check the sewing quality, such as the thread tension or the texture, in the sewing machines of Patent Documents 6 and 7, the finished work must be checked with the aid of test devices or the like after several sewing processes have been completed. In brief, the prior art sewing machines disclosed in Patent Documents 6 and 7 drive the pressing device so that sewing quality such as thread tension or tightening accuracy is improved, but there is a problem that the quality of the seam to be made is not can be guaranteed.

The present invention was made in view of the above, and an object of the invention is to provide a sewing machine which, with a simple structure of a few additional components, monitors the occurrence of thread breaks during sewing and also the sewing quality, such as the thread tension or the tightening accuracy, can ensure.

SOLVING THE PROBLEM

A sewing machine according to the present invention comprises: a sewing needle having an eye of a needle through which an upper thread is passed; a looper that chains the upper thread and a lower thread together by catching the upper thread; a thread lever which has a small hole through which the upper thread is passed and which lifts the upper thread of a sewing material which is the object to be sewn by lifting the small hole from a lower dead point to an upper dead point; a central foot that prevents the material from being lifted upwards; a drive source that drives the center leg; a transport unit for transporting the sewing material; and a tension monitoring element that monitors the upper thread tension on the basis of a load exerted on the central foot by the upper thread as a result of the upper thread coming into contact with the central foot when the sewing material is being transported by the transport unit.

ADVANTAGEOUS EFFECTS OF THE INVENTION

According to the present invention, the tension exerted on the upper thread via the central foot can be detected, and a thread breakage or a tightening accuracy, which is related to the sewing quality, can be detected with a simple one Configuration of a few additional components can be recorded.

Figure list

• 1 FIG. 13 is a perspective view showing an overall configuration of a sewing machine according to Embodiment 1. FIG.
• 2 FIG. 13 is a perspective view showing details of a transport mechanism of the sewing machine according to Embodiment 1. FIG.
• 3 FIG. 13 is a perspective view showing a sewing mechanism of the sewing machine according to Embodiment 1. FIG.
• 4th FIG. 13 is a perspective view showing details of a center foot drive mechanism of the sewing machine according to Embodiment 1. FIG.
• 5A and 5B 14 are perspective views showing an upper thread guide path of the sewing machine according to Embodiment 1. FIG.
• 6th FIG. 13 is a block diagram showing a control configuration of the sewing machine according to Embodiment 1. FIG.
• 7th Fig. 13 is a view for explaining the operation of a conventional electronic sewing machine.
• 8th FIG. 13 is a view illustrating a tension detection operation on the sewing machine in accordance with Embodiment 1. FIG.
• 9 FIG. 13 is a timing chart showing the functional scheme of a sewing needle and a central foot of a general electronic sewing machine and the sewing machine according to Embodiment 1. FIG.
• 10 FIG. 13 is a timing chart showing the operation of the sewing machine in accordance with Embodiment 1. FIG.
• 11 FIG. 13 is a block diagram showing details of an LF shaft motor control calculation unit of the sewing machine according to Embodiment 1. FIG.
• 12th FIG. 13 is a block diagram showing details of an LF wave deviation suppressing element of the sewing machine according to Embodiment 1. FIG.
• 13th FIG. 13 is a block diagram showing details of a tension monitoring unit of the sewing machine according to Embodiment 1. FIG.
• 14th FIG. 13 is a timing chart illustrating the operation of a sewing machine according to Embodiment 2. FIG.
• 15A and 15B are views showing a result of a tension detection operation on a sewing machine according to Embodiment 3. FIG.
• 16 FIG. 13 is a timing chart showing the operation of a sewing machine according to Embodiment 3. FIG.
• 17th FIG. 13 is a block diagram showing details of an LF shaft motor control calculation unit of the sewing machine according to Embodiment 4. FIG.
• 18th FIG. 13 is a block diagram showing details of an LF wave deviation suppressing element of the sewing machine according to Embodiment 4. FIG.
• 19th FIG. 13 is a view showing a first hardware configuration example of a control panel of a sewing machine according to Embodiments 1 to 4. FIG.
• 20th FIG. 13 is a view showing a second hardware configuration example of a control panel of a sewing machine according to Embodiments 1 to 4. FIG.

DESCRIPTION OF EMBODIMENTS

In the following, a sewing machine according to embodiments of the present invention is described in detail with reference to the figures. The present invention is not limited to the embodiments.

Embodiment 1

In a first embodiment, an example of a structure of an industrial electronic sewing machine that performs sewing while sewing an object to be sewn, which is a sewing material such as cloth or leather, by means of a transport device such as an XY table will be described emotional. However, the configuration example of the embodiments can also be used, for example, in a common sewing machine, an industrial sewing machine, a household sewing machine, an embroidery machine and the like, the sewing machine having at least one pressure device such as a presser foot or a central foot and the material to be sewn can be transported in such a way that a Upper thread comes into contact with the pressure device.

First, the 1 until 5 an example of a structure of a sewing machine 100 according to the present embodiment described, with the right-handed XYZ coordinates of the 1 until 5 a direction in which a sewing needle moves up and down is defined as the Z-axis direction, a direction orthogonal to the Z-axis direction as the X-axis direction, and a direction orthogonal to both the Z-axis direction and the X-axis direction is defined as the Y-axis direction . The X-axis direction corresponds to a longitudinal direction of a sub-structure described later.

The main components of an in 1 illustrated sewing machine 100 include a housing mechanism P0, a transport mechanism P1 shown in FIG 2 is shown in detail, a control device P2 and a sewing mechanism P3 shown in FIG 3 is shown.

How out 1 As can be seen, the housing mechanism comprises P0 of the sewing machine 100 : one arm 101 , in which an upper shaft is housed, which is part of the sewing mechanism P3 of FIG 3 is; a main shaft motor housing 102 for housing a main shaft motor connected to the upper shaft; a sewing machine head 103 , in which the sewing mechanism P3 sews a distal end of the arm 101 executes; a substructure 104 for receiving an XY table which is part of the transport mechanism P1; a support leg 105 holding the arm 101 and the substructure 104 supported on a mounting base, and a sliding plate 106 attached to an upper surface of the substructure 104 is attached and the holding device comprised by the transport mechanism P1 112 supported so that it can slide on a flat surface.

The housing mechanism P0 is made of a material such as a high-strength steel plate or a cast material, or a shock-dispersing and absorbing flexible material, which is designed to be mechanically broken from impacts when the sewing machine is operated 100 withstands.

Even if the main shaft motor housing 102 in 1 for attachment to one end of the arm 101 is configured to specifically illustrate the arrangement of the main shaft motor, the main shaft motor 201 of FIG 3 also within the arm 101 be included. Furthermore, the main shaft motor 201 of FIG 3 also in the sewing machine head 103 integrated and not within the arm 101 be arranged.

As in 1 is shown, the transport mechanism P1 is the sewing machine 100 the XY table 111 and a holding device 112 on. In 2 becomes the XY table 111 driven in the direction of the X-axis by an X-axis drive motor and in the direction of the Y-axis by a Y-axis drive motor and moves with a movable portion of the XY table 111 connected holding device 112 on a horizontal surface of the slide plate 106 .

In the present embodiment, it is the X-axis motor 113 and the Y-axis motor 114 around servomotors attached to one side of the base 104 and an X-axis drive mechanism 115 and a Y-axis drive mechanism, respectively 116 drive. As in 2 is shown in detail, the XY table transports 111 the one with the moving part of the XY table 111 connected holding device 112 on the horizontal surface of the slide plate 106 , where the X-axis motor 113 and the Y-axis motor 114 serve as drive sources in the X or Y axis direction. The X-axis drive mechanism 115 uses a movable slide as a movable element 115a that with the holding device 112 connected, and the Y-axis drive mechanism 116 uses a Y-axis guide as a movable element 116a that come with the holding device 112 connected is.

On the X-axis motor 113 and the Y-axis motor 114 are each rotation information detectors 117 and 118 attached to the acquisition of rotational information such as angle and angular speed of a rotor relative to a stator. As rotation information detectors 117 and 118 In the present embodiment, optical encoders can be specified which detect the angle of the rotor relative to the stator. The angular velocity and angular acceleration of the rotor can be determined by differentiating a detected angle signal.

The one with the XY table 111 connected holding device 112 includes a pressure bar 112a , a transport plate 112b , an upper pusher 112c and a pneumatic cylinder 112d . The pressure bridge 112a is with the movable slide 115a , the Y-axis guide 116a and the XY table 111 connected, the sliding plate 106 at the other end with the transport plate 112b and the top pusher 112c connected is. The transport plate 112b is at the top of the sliding plate 106 arranged and moves when the XY table is driven 111 sliding on the sliding plate 106 . The sewing material, which is an object that the sewing machine is working on 100 forming a seam is between the transport plate 112b and the top pusher 112c arranged and is from the holding device 112 held by the top pusher 112c vertically downwards against the transport plate 112b is pressed.

The holding device 112 alternates between holding and not holding the sewing material using the pneumatic cylinder 112d as Drive source around. The holding device 112 carries out a transport process for holding and transporting the sewing material in such a way that a needle penetration position of the sewing needle in relation to the sewing material is a certain one specified by the user of the sewing machine 100 corresponds to the specified position.

To the holding force of the holding device 112 In the present embodiment, to ensure the air pressure with the pneumatic cylinder 112d is set, but the invention is not limited thereto, and the sewing material can also be held by means of an electromagnetic pressure device or a hydraulic pressure device. Furthermore, the configuration of the transport mechanism P1 is not limited to that in 2 The configuration shown is limited, although the technique shown in the present embodiment for detecting the upper thread tension can also be used in other types of sewing machines that convey the sewing material to the sewing needles by means of conveyors, or in sewing machines that transport the sewing material with the aid of robots. In 2 are the X-axis drive mechanism 115 and the Y-axis drive mechanism 116 furthermore equipped with a toothed belt mechanism, but not limited thereto, and a ball screw mechanism or a ball screw mechanism can also be used. In addition, the drive source is the XY table 111 not limited to a rotary electric machine, and a variety of linear motors, planar motors and spherical motors or the like can be used.

The control device P2 of the sewing machine 100 includes a control panel 121 , a control console 122 and a foot switch 123 . The user of the sewing machine 100 based on sewing data, for example with the help of the control panel 121 generated sewing pattern data, a sewing instruction signal for controlling the sewing machine 100 from the control panel 121 to the control console 122 the end. The control console 122 controls the transport operation of the transport mechanism P1 and also controls the speed and timing of the sewing work carried out with the aid of the sewing mechanism P3 described later. By pressing a button on the foot switch 123 or a touch panel by the user of the sewing machine 100 are attached to the control console 122 an operation start signal for starting sewing work by the sewing machine 100 and a hold signal for switching between holding and not holding the sewing material with the aid of the holding device 112 issued. The operation of the control device P2 will be described following the description of details of the sewing mechanism P3.

The details of the sewing machine sewing mechanism P3 100 according to the present embodiment, referring to FIG 3 until 5 described. As in 3 As shown, the sewing mechanism P3 comprises: a sewing needle 131 with the eye of a needle; a gripper 132 that grips the upper thread and chains the upper thread and a lower thread together; a take-up lever 133 which tightens the seam to be formed by lifting the upper thread from the sewing material; a main shaft motor 134 , which is a drive source that the sewing needle 131 , the gripper 132 and the take-up lever 133 drives; a central foot 135 which prevents the material from being lifted upwards; and a center foot motor that is a drive source for the center foot 135 represents. In addition, as shown in FIG 5B is shown, a thread pretensioner 162 and a main thread tensioner 163 to adjust the upper thread tension.

The sewing needle 131 has the eye of a needle 131a through which the upper thread, which is a thread located on the top when the seam is formed, is passed, and moves using the main shaft motor 134 as a drive source in the direction of the Z-axis up and down. The sewing needle 131 reaches the lower dead center point after it has been lowered from the upper dead center point and inserted into the sewing material, whereby the sewing needle 131 is then pulled out of the material when lifting from the lower reversal point to the upper reversal point. The sewing needle 131 works after reaching the lower reversal point until it is pulled out of the sewing material with the hook 132 together, whereby the upper thread is linked with the lower thread, which is a thread located on the underside of the sewing material when the seam is formed. The needle thread is then pulled out when the eye of the needle is pulled out 131a the sewing needle 131 pulled out of the sewing material at the top of the sewing material.

On the main shaft motor 134 is a rotation information detector 137 for detecting rotational information, such as the angle and angular speed of the rotor in relation to the stator, attached. In the present embodiment, the rotation information detector 137 an optical encoder specified the angle of the rotor in relation to the stator of the main shaft motor 134 recorded. The main shaft motor 134 is on the arm 101 attached, one end of the shaft-shaped upper shaft 139 via a clutch 138 with the rotor of the main shaft motor 134 connected is.

A rotary motion of the upper shaft 139 is operated by a take-up lever drive mechanism 140 and a needle bar drive mechanism 141 the one on the other not with the clutch 138 connected end of the upper shaft 139 is appropriate in an up and down movement of the needle bar 142 translated. The sewing needle 131 is at a distal end of the needle bar 142 mounted, with the sewing needle 131 when the needle bar moves up and down 142 moves up and down in the direction of the Z-axis. The needle bar drive mechanism 141 holding the sewing needle 131 with the help of the main shaft motor 134 up and down as a drive source, is equipped with a crank, a connecting rod, a needle bar holder and the like, but since this is a known technology, further descriptions with reference to an enlarged view or the like can be omitted.

The gripper 132 is a rotary hook with a hook, a bobbin wrapped with the bobbin thread and a bobbin case 143 designed, which is designed to receive the coil so that the coil cannot fall out of the rotary hook. In the present embodiment, as a gripper 132 a fully rotating gripper is used, but the present invention is not limited thereto. The gripper 132 can be, for example, a semi-rotating gripper, a horizontal boat or a vertical boat.

The gripper 132 uses the main shaft motor 134 as a drive source. In 3 is near the junction of one end of the upper shaft 139 with the clutch 138 a pulley 144 for the upper shaft concentrically on the upper shaft 139 attached, with the drive-side pulley 144 for the upper shaft 144 via a toothed belt 145 a belt pulley on the output side 146 for the lower shaft rotates. The pulley 146 a gear wheel rotates over the shaft for the lower shaft 147 large diameter and one in the gear 147 large diameter meshing gear 148 with a small diameter. In this configuration, one rotates with the gear 148 small diameter connected shaft-shaped lower shaft 149 , with opposite the upper shaft 139 double speed.

The gripper 132 and the lower shaft 149 are with the lower shaft 149 at one end of the shaft, on which the gearwheel 148 small diameter is not attached, connected, causing the gripper 132 rotates at twice the frequency with which the sewing needle rotates 131 when the main shaft motor rotates 134 moves up and down. At this point the hook of the gripper catches 132 a loop that goes through the eye of the sewing needle 131 guided upper thread forms when the sewing needle 131 is lowered, guided through the material and, after reaching the lower reversal point, is raised in the direction of the upper reversal point. Since the configuration of a full revolving hook is a known technology, further description with reference to an enlarged view or the like will be omitted.

The take-up lever 133 is with the take-up lever drive mechanism 140 connected to the main shaft motor 134 uses as a drive source and is designed with a crank or a thread lever rod. The take-up lever 133 is a rigid body made of a metallic material in the form of a rocker arm, one end of which has a small hole 133a is provided for inserting the upper thread, and the other end with that with the upper shaft 139 connected crank is rotatably connected. The other end of the one end rotates with the arm 101 connected thread lever rod is connected to a curved area of the deflection lever contour. In this configuration, the take-up lever 133 from which is in sync with the main shaft motor 134 rotating upper shaft 139 driven, being a cycle of up and down movement of the sewing needle 131 a cycle of up and down movement of the take-up lever 133 is equivalent to. The little hole 133a of the take-up lever 133 is usually moved so that it reaches the top dead center when the angle of rotation of the main shaft motor 134 opposite the upper turning point of the sewing needle 131 about 60 degrees behind. As the configuration of the take-up lever drive mechanism 140 to drive the take-up lever 133 is a known technology, further description is omitted with reference to an enlarged view or the like.

Next is a drive mechanism for the central foot 135 according to the present embodiment with reference to FIG 4th described. The central foot 135 is with a central foot drive mechanism 151 connected, in which a central foot motor as the drive source 136 with a rotation information detector 150 is used. The central foot drive mechanism 151 drives a sewing foot shaft (NF shaft) of the sewing machine 100 on. The central foot motor 136 includes a rotation information detector 150 , which is the angle or the speed of the rotor in relation to the stator of the central foot motor 136 recorded. In the present embodiment, the rotation information detector 150 an optical encoder is listed, which detects the angle of the rotor relative to the stator.

The central foot drive mechanism 151 includes a pinion 152 , a rack 153 , a sliding guide 154 , a runner 155 , a central foot bar holder 156 and a central foot bar 157 .

In the present embodiment, the central foot motor is 136 one on the arm 101 attached servo motor, with the small circular hole in the center of the pinion 152 , which has a circular gear shape with a small diameter, on the rotor is appropriate. The teeth of the pinion 152 grip the teeth of the rack 153 and convert the rotational movement of the central foot motor 136 into a translational movement of the rack 153 around. The rack 153 is with the runner 155 connected, being the runner 155 on the sliding guide 154 is guided so that it moves up and down in the Z-axis direction. The central foot rod holder 156 is with a screw on the runner 155 attached, with the central foot bar 157 with the help of the central foot rod holder 156 is used, tightened and fastened. The central foot 135 is at the distal end of the central foot bar 157 attached, with the central foot 135 moves up and down when the central foot bar moves 157 moves up and down in the direction of the Z-axis. At the distal end of the central foot 135 is a round through hole 135a formed through which the sewing needle is guided. Because of this configuration, the sewing machine 100 the height of the central foot 135 the rotation of the central foot motor 136 independently of the other sewing mechanisms.

In the present embodiment, the central foot motor 136 a servomotor of the rotary type, ie a rotary electric machine with an annular stator and a cylindrical rotor, is used, the rotational movement of the rotor being converted into translational movement of the central base via the rack and pinion 135 is translated. The drive source of the central foot 135 however, it is not applicable to a rotary electric machine such as e.g. B. a servo motor or a stepping motor, but can also be an actuator that directly implements a translational movement of a linear motor, a voice coil motor or the like. By using them, the loss of power transmission caused by the rack and pinion mechanism can be reduced. Since the influence of play or friction is also reduced by the simpler mechanism, one can touch the central foot from outside 135 acting external force can easily be recorded based on the behavior of the actuator.

With reference to the 5A and 5B becomes one with the control of the upper thread guide path and the upper thread tension of the sewing machine 100 related sewing mechanism described. 5A Fig. 13 is an overall view showing the entire upper thread guide path of the sewing machine 100 illustrates, and 5B an enlarged view showing the upper thread guide path on the sewing machine head 103 illustrated. Before executing a sewing operation on the sewing machine 100 a user of the sewing machine threads 100 the upper thread T , which forms the thread on the top when the seam is formed, starting from a bobbin 159 , which is a supply source for the upper thread T represents, up to the sewing needle 131 a, which represents a removal point of the upper thread guide path. The upper thread guide path has that on a bobbin stand 158 recorded coil 159 as a starting point and extends over the upper thread guides in the specified order 160 and 161 , the thread pretensioner 162 , the main thread tensioner 163 , the little hole 133a of the take-up lever 133 and the upper thread guides 164 , 165 and 166 up to the one at the distal end of the sewing needle 131 trained eye of a needle 131a as an end point. As the sewing needle 131 through the through hole formed in the cylindrical part at the distal end of the central foot 135a is led through the eye of the needle 131a guided upper thread T through the through hole 135a guided. The upper thread guides 160 , 161 , 164 , 165 and 166 are holes through which the upper thread T is guided, with the upper thread T so on the arm 101 run along that the upper thread T is not tangled or unwound. The upper thread tension T is controlled by a spring that is part of the thread pretensioner 162 and the main thread tensioner 163 is applied, and a plate that clamps the thread.

Next, a control configuration of the sewing machine is made 100 according to the present embodiment with reference to FIG 6th described. 6th FIG. 13 is a block diagram showing the control configuration of the sewing machine in accordance with Embodiment 1. FIG. The ones with the reference number 122A control panel is the same as in 1 control console shown 122 .

As in 6th includes the control panel 121 the sewing machine 100 a display 121a , a processor 121b , a storage device 121c to save the sewing pattern data D1 and an input device 121d . A user of the sewing machine 100 gives the sewing pattern data D1 for each stitch by using the input device equipped with a push button or a touch panel 121d operated and on the display 121a Refers. The sewing pattern data D1 are in this case in the storage device 121c saved. The operating system of the operator console 121 is used by the processor 121b operated. The use of the in the storage device 121c saved sewing pattern data D1 simplifies the creation, editing and duplication of the sewing pattern.

The one on the control panel 121 generated sewing pattern data D1 are used by the processor 121a converted into a sewing instruction signal and sent to an instruction generating unit 1A1 the control console 122A transfer. The sewing pattern data D1 are data relating to the position and shape of the seam formed on the material and the working speed of the sewing machine 100 establish. The transmission of signals between the control console 121 and the control console 122A takes place via a communication circuit (not shown).

the display 121a the control console 121 receives as input a voltage monitoring signal obtained from an LF shaft motor control calculation unit 1A3 the control console 122A is issued to the user of the sewing machine 100 indicates that a sewing error has occurred if a thread break is detected on the basis of the tension monitoring signal and if the upper thread tension changes with each stitch, although the same seam is formed.

Furthermore, the display 121a not on a display in the control panel 121 limited, it can also be a display such as a liquid crystal display or a signal mechanism that is outside the control panel 121 is located. In this case, communication between the display and the control console can be avoided 122A either wired or wireless. In addition, the display 121a in the control console 122A be integrated.

So is the storage device 121c not on a device in the control panel 121 limited, it is also possible to use a storage medium that is located outside the control console 121 is located. In this case, the communication between the storage device and the control console 122A either via a wired communication unit or a wireless communication unit.

As in 6th shown includes the control console 122A to control the sewing machine 100 at least the instruction generation unit 1A1 , a main shaft motor control calculation unit 1A2 , the LF shaft motor control calculation unit 1A3 , an X-axis motor control calculation unit 1A4 and a Y-axis motor control calculation unit 1A5 . Besides, a control circuit and a power supply circuit that drive an electromagnet that cuts the thread after sewing is completed, a sensor that indicates loss of thread, a position sensor for returning the transport mechanism P1 to a starting point, and the like may be provided; however, since the control circuit and the power supply circuit are not directly related to the effects of the present invention, they will not be described.

The control console 122A receives one from the processor 121b the control console 121 sewing instruction signal output, one from the foot switch 123 output hold signal and operation start signal, a main shaft rotation signal which is rotation information of the main shaft motor 137 is that of the rotation information detector 137 of the main shaft motor 134 is output, an LF shaft rotation signal, which is rotation information of the central foot motor 136 is that of the rotation information detector 150 of the central foot motor 136 is outputted, an X-axis rotation signal which is rotation information of the X-axis motor 113 is that of the rotation information detector 117 of the X-axis motor 113 is output, and a Y-axis rotation signal obtained from the rotation information detector 118 of the Y-axis motor 114 is issued.

The control console 122A gives a main shaft control current to drive the main shaft motor 134 , an LF wave control current to drive the central foot motor 136 , an X-axis control current for driving the X-axis motor 113 , a Y-axis control current for driving the Y-axis motor 114 , a restraint instruction signal that the pneumatic cylinder 112d drives, and a voltage monitoring signal that is generated by the LF shaft motor control calculation unit 1A3 is output.

The instruction generation unit 1A1 the control console 122A receives this from the processor 121b the control console 121 sewing instruction signal output as well as the hold signal and that of the foot switch 123 outputted operation start signal as input and outputs a main shaft instruction signal, an LF shaft instruction signal, an X-axis instruction signal, a Y-axis instruction signal, and a hold instruction signal. The main shaft instruction signal, LF shaft instruction signal, X-axis instruction signal, and Y-axis instruction signal are electrical signals each representing the rotation angles of the main shaft motor 134 , the central foot motor 136 , the X-axis motor 113 or the Y-axis motor 114 set and in the instruction generation unit 1A1 the sewing pattern data D1 calculated accordingly.

The one from the foot switch 123 The output hold signal is an electrical signal that indicates the pressure of the pneumatic cylinder 112d so that the material to be sewn from the transport plate 112a and the top pusher 112b the holding device 112 is being held. The one from the foot switch 123 output operation start signal is an electrical signal that determines the point in time at which the instruction generation unit 1A1 with sending the main shaft instruction signal, the LF wave instruction signal, the X-axis instruction signal and the Y-axis instruction signal to the main shaft motor control calculation unit 1A2 , the LF shaft motor control calculation unit 1A3 , the X-axis motor control calculation unit 1A4 and the Y-axis motor control calculation unit, respectively 1A5 records.

The main shaft motor control calculation unit 1A2 the control console 122A receives the main shaft instruction signal and the main shaft rotation signal as input and outputs a main shaft control current that controls the main shaft motor 134 rotates so that the difference between the main shaft instruction signal and the main shaft rotation signal becomes zero.

The LF shaft motor control calculation unit 1A3 the control console 122A receives the LF shaft instruction signal and the LF shaft rotation signal as input, and outputs a LF wave control current that controls the central foot motor 136 rotates so that the difference between the LF shaft instruction signal and the LF shaft rotation signal becomes zero. In addition, the LF shaft motor control calculation unit monitors 1A3 the tension of the upper thread when lifting the small hole 133a of the take-up lever 133 with the rotation of the main shaft motor 134 and outputs an upper thread tension monitoring signal. In other words, the sewing machine is 100 configured according to the present invention so that the LF shaft motor control calculation unit 1A3 the upper thread tension is monitored. The X-axis motor control calculation unit 1A4 the control console 122A receives the X-axis instruction signal and the X-axis rotation signal as inputs and outputs an X-axis control current that controls the X-axis motor 113 rotates so that the difference between the X-axis instruction signal and the X-axis rotation signal becomes zero.

The Y-axis motor control calculation unit 1A5 the control console 122A receives the Y-axis instruction signal and the Y-axis rotation signal as input and outputs a Y-axis control current that controls the Y-axis motor 114 rotates so that the difference between the Y-axis instruction signal and the Y-axis rotation signal becomes zero.

Next, a description will be given of an operation in which the sewing machine 100 forms a seam. First, the user performs the sewing machine 100 the upper thread T off the spool 159 along the upper thread guide path described above and into the eye of the needle 131a on. The bobbin thread Td , which forms the thread on the underside when the seam is formed, is around the one in the bobbin case 143 of the gripper 132 recorded coil wound.

If the user then presses the foot switch 123 the sewing machine 100 and presses the hold signal to the instruction generation unit 1A1 the control console 122A is sent, the pneumatic cylinder 112d by that from the instruction generation unit 1A1 The stop signal output is actuated and the material to be sewn is stopped in the in 1 shown holding device 112 pinched so that it can be transported. When the foot switch 123 is still pressed and the start signal to the control panel 122A is sent, the X-axis motor will rotate 113 and the Y-axis motor 114 , which are the drive sources for the transport mechanism P1 and the main shaft motor 134 and the central foot motor 136 which are the driving source for the sewing mechanism P3 and the sewing machine 100 starts on a specific by the user of the sewing machine 100 using the control panel 121 to form a seam in the pre-determined position of the sewing material. This is how the sewing needle becomes 131 when turning the main shaft motor 134 by means of the main shaft motor control calculation unit 1Ab of the control panel 122A with the one through the eye of the needle 131a guided upper thread T into the sewing material from the top towards the bottom of the sliding plate 106 introduced. By operating the sewing needle 131 becomes the upper thread T guided to the underside of the sewing material. When the sewing needle 131 is guided upwards from the lower reversal point, forms the upper thread T Due to the friction with the sewing material, a loop forms on the underside of the sewing material.

The hook of the gripper 132 catches the upper thread synchronized with the point at which the upper thread is looped T and chains the upper thread with the bobbin thread. When the hook of the gripper 132 detects the upper thread, the angle of rotation of the main shaft motor is usually in a range from 190 to 210 degrees, the angle of rotation of the main shaft motor being 0 degrees when the sewing needle is at the top dead center. After the upper thread and bobbin thread have been linked, the upper thread becomes the sewing needle when it is pulled out 131 pulled out of the sewing material at the top of the sewing material. In addition, the upper thread T by lifting the upper thread with the thread take-up lever 133 stretched above the sewing material and the seam is formed. At this point the central foot is pressing 135 when lifting the sewing needle 131 and the take-up lever 133 the sewing material down so that the sewing material is not lifted up and does not flutter.

In addition, the upper thread is tightened by the thread pretensioner 162 and the main thread tensioner 163 during a period in which the sewing machine 100 forms a seam, constantly tensioned.

Next will be the operation of upper thread tension detection in the sewing machine 100 according to Embodiment 1 of the present invention with reference to FIG 7th until 13th described.

First, referring to the 7th until 9 the functional features of detecting the upper thread tension on a sewing machine 100 according to the present embodiment in comparison with the operation of a conventional electronic sewing machine.

7th and 8th show the positional relationship between the sewing needle, central foot and material to be sewn when the sewing needle is lowered from the upper reversal point to the lower reversal point and raised again to the upper reversal point and the seam is formed for a conventional electronic sewing machine or a sewing machine 100 according to the present embodiment. In both figures, the seam is already formed up to the (N-1) th stitch, whereupon the sewing needle is lowered to carry out the sewing process for the N th stitch.

9 illustrates the course of a movement path of the sewing needle and central foot of a conventional electronic sewing machine and a sewing machine according to the present invention. 9 shows the rotation angle of the main shaft motor when the sewing needles move 131 ' and 131 when sewing the (N-1) th stitch at a point in time a indicated by dashed lines at the upper reversal point, the sewing needles are located 131 ' and 131 to be inserted at a time b, the sewing needles 131 ' and 131 are at a point in time c at the lower reversal point, the looper picks up the loop of the upper thread at a point in time d and the sewing needles 131 ' and 131 to be withdrawn at a time e. Similarly, the times a 'to e' represent times when the sewing machine 100 sews the Nth stitch. 7th and 8th show an operating state in which the rotation angle of the main shaft motor is at the point in time a 'of the time chart of FIG 9 is equivalent to. A black circle (•) at the top of 9 explicitly marks the position of the sewing needle at time d when the looper picks up the upper thread loop.

As in the upper part of 9 shown, the sewing needles are moving 131 ' and 131 with a stroke lh up and down. As in the middle and lower part of 9 is shown, the central feet move 135 ' and 135 with a hub lo up and down. In contrast, the curves show in the middle and lower part of 9 the movements of the underside of the central foot 135 , being the central foot 135 is driven so that it is stopped at a position at which the bottom of the central foot 135 during the period from time e to time b ', during which the sewing needles 131 ' and 131 withdrawn from the sewing material and inserted again, is at a distance dlo above the sewing material. The distance dlo is at least longer than the diameter of the upper thread T so that the upper thread T between the central foot 135 and a sewing material If can run through.

The central foot 135 ' a common electronic sewing machine from 7th becomes sinusoidal and essentially in phase with the movement path of the sewing needle 131 ' driven. When the sewing needle 131 ' is at the top dead center is the sewing needle 131 ' in comparison with 8th positioned further away from the sewing material Ob '. More precisely, as in the middle part of 9 Explicitly marked by a white circle (O), the central foot 135 ' a conventional sewing machine driven in a sinusoidal path in order to press down the sewing material at the point in time d at which the hook of the looper picks up the loop of the upper thread. Especially when a standard electronic sewing machine is used and the central foot 135 ' uses the main shaft motor as a drive source, one can be shown in the lower part of 9 shown drive pattern of the central foot can only be realized with difficulty. Since the central foot 135 in 8th from the central foot motor 136 is driven independently, the central foot 135 at the time a 'at which the sewing needle 131 is positioned at the upper reversal point, on one of the sewing material If be held a distance dlo spaced position.

Incidentally, the upper thread T 'or the upper thread T the tension between the sewing material Ob 'and the small hole is generated when the small hole of the thread lever is lifted. The main concern of this invention is to ensure sewing quality by detecting the amount of tension based on the behavior of the central foot motor 136 while sewing without using a special detector. The sewing machine according to the invention controls this 100 the transport mechanism P1, which the sewing material If so that the upper thread T and the central foot 135 come into contact with each other. Plus, as in 8th is shown, characterized in that by stopping the central foot 135 on one of the sewing material If by the distance dlo spaced position while the small hole of the thread lever is raised, the influence of the force on the central foot motor 136 through the upper thread T is larger than that of the upper thread T '.

In the following, with reference to 10 a sewing and transport process described in which the sewing machine 100 according to the present embodiment, the upper thread tension is detected.

10 shows the movements of a driven object on the (n-1) th and subsequent stitches when the sewing machine 100 repeated the sewing processes of n or more stitches (n ≥ 3) relative to the material to be sewn If at the top of the sliding plate 106 executes. Specifically, the figure shows the position of the eye of the needle from top to bottom 133a the sewing needle 131 , the angle of rotation of the hook of the gripper 132 , the position of the central foot 135 , the position of the small hole 133a of the take-up lever 133 , the position of the sewing material transported by the transport mechanism P1 in the direction of the X-axis and the position of the sewing material transported by the transport mechanism P1 in the direction of the Y-axis.

As in the top part of 10 shows the eye of the needle 131a the sewing needle 131 using the main shaft motor 134 as the drive source the same trajectory as in 9 , the eye of the needle 131a is at the top reversal point at time a, is inserted into the sewing material at time b, is at the lower reversal point at time c and is pulled out of the sewing material at time e. The point in time d is the point in time at which the hook of the gripper 132 picks up the needle thread loop, with the black circle (•) indicating the position of the sewing needle 131 explicitly marked at this point. In addition, the stroke of the sewing needle is 131 similar to in 9 lh.

The second partial representation of 10 shows the rotation angle of the gripper 132 using the main shaft motor 134 as a drive source, with a course of movement of the gripper 132 corresponds to a sinusoidal curve with the amplitude lk. In the present embodiment, the course of the rotational movement of the gripper 132 a frequency twice as high as the position of the sewing needle 131 because a completely rotating gripper is used. The black circle (•) in the figure explicitly marks the angle of rotation of the gripper 132 when the loop formed by the upper thread is picked up by the hook of the looper 132 . The one from the hook of the grapple 132 recorded upper thread T is from the gripper 132 released at the time the gripper is 132 has turned one and a half times since the angle of rotation a.

In the third partial representation of 10 is a position history of the small hole 133a of the take-up lever 133 using the main shaft motor 134 to be seen as a drive source. The little hole 133a of the take-up lever 133 is driven so that the rotation of the main shaft motor 134 at time h corresponds to the upper reversal point and at time i corresponds to the lower reversal point, with one revolution of the main shaft motor 134 corresponds to a cycle. The point in time h is determined by mechanically adjusting the fulcrum around which the thread lever drive mechanism 140 commutes, set so that it is within a period of time from the start of rotation of the main shaft motor 134 until the needle penetrates 131 into the sewing material If is located, ie at an angle of rotation of the main shaft motor 134 in a time span extending from a to b. In the present embodiment, the time point h corresponds to an angle made by rotating the main shaft motor 134 is obtained by 60 degrees from the time point a.

The time i at which the small hole 133a is at the bottom reversal point, corresponds to the point in time of one and a half times the gripper rotation 132 . Because at the angle of rotation i of the main shaft motor 134 the upper thread caught by the gripper 12 begins to detach from the latter. When the little hole 133a is lifted before the upper thread caught by the looper 132 is released, the upper thread can T the tension applied when lifting the take-up lever 133 arises, no longer withstand and the problem arises that the upper thread can loosen or the upper thread breaks. Further, the time i in the present embodiment corresponds to an angle made by rotating the main shaft motor 134 is obtained by 270 degrees from the time point a. That's why the little hole becomes 133a of the take-up lever 133 when sewing the (N-1) -th stitch is lowered during a time period td extending from time h to time i, and is raised for the N-th stitch during a time period tu extending from time i to time h '. The relationship td> tu exists between the period td and the period tu.

Similar to the bottom part of 9 shows the fourth partial representation of from above 10 the position of the underside of the central foot 135 when using the central foot motor 136 as a drive source. After the central foot 135 by turning the central foot motor 136 begins to lower starting from the upper turning point, becomes the central foot 135 until time b, at which the sewing needle 131 into the sewing material If is inserted at the top of the fabric If brought to the facility. When the sewing material If consists of a non-elastic material, the central foot presses 135 the sewing material If downwards at the height at which the central foot 135 when lowering to the sewing material If bumps. In this case, the lower turning point of the central foot corresponds to the height, at the bottom of the central foot 135 to the sewing material If abuts, with the central foot 135 moves up and down with a stroke lo from the top dead center to the bottom dead center.

When the sewing material If consists of a material with high elasticity, the central foot presses 135 the sewing material If downwards at the height at which the central foot 135 when lowering the sewing material If compressed. In this case, the lower reversal point of the central foot corresponds to the height at which the sewing material If is compressed. Then the Central foot 135 the sewing material If before piercing the sewing needle 131 into the sewing material If press down and will after retracting the sewing needle 131 a stretch dlo of the sewing material If lifted.

The fifth partial representation of 10 shows a position profile of the holding device 122 taken from the X-axis motor 113 is moved in the direction of the X-axis. As the holding device 122 the sewing material If holds, the position progression corresponds to the position progression of the sewing material If in the X-axis direction. The symbol lx in the figure corresponds to a movement distance of the holding device 122 that moves in the X direction between each stitch. While the sewing needle 131 into the sewing material If the holding device is inserted 122 still so that the sewing material If will not be damaged or the needle will break, and will after the sewing needle is pulled out 131 from the sewing material If moved until the sewing needle 131 back into the sewing material If is introduced.

In the present embodiment, since the upper thread tension when the thread lever is raised is determined from the behavior of the central foot motor, it becomes the XY table 111 driven so that the upper thread T with the central foot 135 comes in contact when the little hole 133a of the take-up lever 133 is raised. That is why the X-axis motor becomes 113 from the time e at which the sewing needle 131 from the sewing material If is pulled out, driven up to the time i, at which the lifting of the small hole 133a begins. Thus the X-axis motor rotates 113 at the (N-1) -th needle stick during a time period tm from the time point e to the time point i and stops at the N-th stitch during a time period ts from the time point i to the time point e '.

The sixth partial representation of 10 shows a position profile of the holding device 122 taken from the Y-axis motor 114 is moved in the direction of the Y-axis. As the holding device 122 the sewing material If holds, the position progression corresponds to the position progression of the sewing material If in the direction of the Y-axis. The symbol ly in the figure corresponds to a movement distance of the holding device 122 that moves in the direction of the Y-axis between each stitch. In the present embodiment, the Y-axis motor 114 with the same position curve as the X-axis motor 113 driven.

When the sewing material If is moved with lx in the direction of the X-axis and with ly in the direction of the Y-axis, a traverse path L of the XY table 111 , that is, a stitch length, can be obtained by Equation 1 below. $$\mathrm{L.}=\sqrt{l{x}^2+\mathrm{<figure-callout\; id="2"\; label="l\; y"\; filenames="DE112017008004B4\_0013.png,DE112017008004B4\_0014.png"\; state="\{\{state\}\}">l</figure-callout>}{y}^{}{}^2}$$

In addition, the XY table can be moved so that the central foot 135 and the upper thread T come into contact with each other when the bottom of the through hole 135a of the central foot 135 corresponds to a circle with a radius r, the sewing needle 131 in the center of the through hole 135a moves up and down and the distance of movement L is longer than the radius r.

It can also be influenced by the upper thread T on the central foot motor 136 exerted force by reducing the angle θ created by the material If and the upper thread T is formed as in 14th shown enlarged. The angle θ can be obtained by Equation 2. $$\theta =\text{arctan}\left(\frac{dlO}{\mathrm{L.}-r}\right)$$

To decrease the angle θ, (L-r) can be increased or the distance dlo by which the central foot is raised can be decreased.

(Operation of voltage detection with the help of the LF shaft motor control calculation unit 1A3 )

Next, the configuration and process for capturing the on the central foot motor 136 through the upper thread tension T applied force using the LF shaft motor control calculation unit 1A3 the control console 122A with reference to the 11 until 13th described in detail.

As in 11 is shown, the LF shaft motor control calculation unit 1A3 the control console 122A an LF wave deviation suppressing unit 1A3a that controls the rotation of the central pedestal motor 136 controls, a current control unit 1A3b and a tension monitoring unit 1A3c that control the upper thread tension when sewing the sewing machine 100 monitored, on.

The LF shaft motor control calculation unit 1A3a receives a LF shaft instruction signal which is a rotation instruction for the central foot motor 136 is issued by the instruction generation unit 1A1 is output, an LF shaft rotation signal, which is rotation information obtained from that in the central foot motor 136 Rotation information detector included 150 is output, and a voltage monitoring signal output from the voltage monitoring unit 1A3c as input signals and outputs an LF shaft motor drive signal that the central foot motor 136 so controls that the difference between the LF shaft instruction signal and the LF shaft rotation signal becomes 0. The current control unit 1A3b generates an LF wave control current for rotating the central foot motor 136 based on the LF wave motor control signal and feeds the generated LF wave control current into the central foot motor 136 on. The tension monitoring unit 1A3c detects the tension in the upper thread by lifting the small hole 133a of the take-up lever 133 generated voltage based on the LF shaft motor control signal and sends the voltage monitoring signal to the display 121a the control console 121 and the LF wave deviation suppressing unit 1A3a.

As in 12th As shown, the LF shaft deviation suppressing unit 1A3a comprises the LF shaft motor control calculation unit 1A3 a switch a1 , a differentiator a2 and a deviation suppression compensator a3 .

When the switch a1 that from the instruction generation unit 1A1 receives the output LF wave instruction signal and the voltage monitoring signal output from the voltage monitoring unit 1A3c as inputs and during the sewing operation of the sewing machine 100 detects a thread break or a change in the upper thread tension, the central foot motor is stopped when a sewing error occurs by stopping a change in value of the LF wave instruction signal on the basis of the tension monitoring signal. By one the switch a1 If a function corresponding to the main shaft instruction signal is also provided for the X-axis instruction signal and the Y-axis instruction signal, the operation of the entire sewing machine can be stopped when a sewing failure occurs. This can prevent the sewing machine 100 carries out another sewing process after the occurrence of a sewing error.

The differentiator a2 calculates a difference between that from the switch a1 output LF wave instruction signal and that from the rotation information detector 150 output LF shaft rotation signal, and outputs a deviation signal. The deviation suppression compensator a3 outputs the LF shaft motor control signal that the LF shaft motor 136 controls in such a way that the deviation signal approaches zero. The deviation suppression compensator a3 comprises a proportional compensator that performs a proportional operation and / or an integral compensator that performs an integral operation and / or a differentiation compensator that performs a differentiating operation so that the deviation signal approaches zero. In the present embodiment, the deviation suppression compensator is used a3 described as a PI controller with the help of the proportional compensator and the integral compensator.

In addition, the voltage monitoring unit 1A3c includes the LF shaft motor control calculation unit 1A3 , as in 13th is shown, a filter processing unit c1 , a recording unit c2 and a comparator c3 .

In order to improve the detection accuracy for the upper thread tension, the filter processing unit calculates c1 an evaluation signal and outputs this by performing a calculation to reduce the frequency component of the LF shaft motor control signal that is higher than the rotational frequency of the main shaft motor 134 and / or performs a calculation to reduce the frequency component of the LF shaft motor drive signal that is lower than the rotational frequency of the main shaft motor 134 is. In addition, in the filter processing unit c1 a proportional operation for changing a phase filter for processing the phase of the LF wave motor drive signal or the amplitude can be performed. By using the phase filter, a detection delay or communication delay of the rotary information detector can be avoided 150 corrected and the accuracy of the point in time for voltage detection can be improved. Furthermore, the evaluation signal can be normalized to any acquisition specification by performing a proportional operation for changing the amplitude by multiplying the gain.

The recording unit c2 draws the filter processing unit when sewing the previous stitch c1 output evaluation signal and at the same time outputs the recorded evaluation signal for synchronization with the current sewing time. In other words, the recording unit can c2 can represent a delay calculator that generates a delay that corresponds to a time that results from a multiplication of the time required for a stitch.

The comparator c3 outputs a voltage monitoring signal to indicate a rate of change of the from the filter processing unit c1 output current evaluation signal in relation to that of the recording unit c2 The evaluation signal output one stitch before is greater or less than a threshold value.

When a seam with a certain shape of the sewing material If is formed, for example, in a constant direction, is the one on the central foot motor 136 through the upper thread tension T over the central foot 135 force exerted evenly when the sewing process and the feeding process the sewing machine 100 can be carried out normally and no sewing error occurs. In this case, the rate of change of the evaluation signal described above is small (ideally constant). If, on the other hand, the rate of change of the evaluation signal described above is high, the upper thread tension detected for each stitch can vary, so that the thread tension and the tightening accuracy are not constant. Also, if from the upper thread T as the upper thread T not in contact with the central foot 135 no force on the central foot motor 136 is exercised and the evaluation signal is zero, the occurrence of a thread break can be detected. In this way, by setting the threshold value for the rate of change of the evaluation signal, the sewing quality can be assessed quantitatively on the basis of the change in the upper thread tension.

In addition, the comparator c3 Calculate the size of a feature such as a maximum value, minimum value and mean value of the evaluation signal in the previous stitch and compare the calculated size of the feature with the current evaluation signal. As a result, the rate of change of the current evaluation signal in relation to the previous stitch can easily be recorded. By normalizing the maximum value and the minimum value of the evaluation signal recorded in the period from time i of the (N-1) th stitch to time h 'of the N th stitch to 100% and 0%, respectively, the rate of change can be calculated, for example, by using the comparator 703 evaluates how much the maximum value and the minimum value decrease from the time i 'of the N-th stitch to the time h' of the (N + 1) -th stitch.

In addition, it is desirable to set the threshold value described above in consideration of the change caused by the sewing direction or the shape of the sewing material for each stitch. Furthermore, the control console 121 and the control panel 122A be designed so that the user of the sewing machine 100 the threshold value determined on the basis of a trial sewing carried out in advance from outside the control console 122A with the help of the input device 121d can adjust. For example, a configuration can be used in which the threshold value in the storage device 121c the control console 121 recorded and processed by the processor 121b or a communication circuit (not shown) to the LF shaft motor control calculation unit 1A3 the operator console 121A is transmitted. Therefore, the criteria for determining the sewing quality can be tailored to the needs of the sewing machine user 100 be changed.

Even when the voltage detection unit 1A3c receives the LF shaft motor drive signal as an input, the voltage monitoring signal can also be calculated and output using the LF shaft control current or the LF shaft rotation signal as an input.

The voltage detection unit 1A3c can configure a disturbance variable observer, which receives the LF shaft motor control signal and the LF shaft rotation signal as input and which is directed to the central foot motor 135 Acting upper thread tension based on a mathematical model of the central foot motor 136 and the central foot drive mechanism.

In addition, by means of the thread pretensioner 162 and the main thread tensioner 163 on the upper thread T applied tension can be controlled on the basis of the tension monitoring signal that the variation of the upper thread tension is reduced with each stitch.

Because the sewing machine 100 according to embodiment 1 the material to be sewn If so that the upper thread T with the central foot 135 comes into contact and that of the upper thread T over the central foot 135 when lifting the small hole 133a of the take-up lever 133 on the central foot motor 136 The force exerted on the basis of the low-frequency wave motor control signal can, as described above, change the force acting on the upper thread by lifting the small hole 133a applied upper thread tension can be detected with each stitch.

Therefore, the sewing machine can 100 Form a seam according to embodiment 1 and thereby ensure the sewing quality, such as the thread tension or the tightening accuracy, which can decisively influence the quality, on the basis of the change in the upper thread tension.

Because the sewing machine 100 According to Embodiment 1, if a seam is formed while guaranteeing the sewing quality for each stitch, it is also possible to recognize a seam in which a sewing error has occurred.

The sewing machine 100 according to embodiment 1 can detect a thread breakage when from the upper thread T no more force on the central foot motor 136 is exercised.

Because the sewing machine 100 According to Embodiment 1, the upper thread tension based on the LF wave motor control signal, which is a drive control signal for the central foot motor 135 is detected, occurrence of thread breakage during sewing is monitored with a simple configuration of a few additional components, and further, sewing quality such as thread tension or tightening accuracy can be ensured.

Furthermore, the sewing machine 100 According to embodiment 1 in comparison to a configuration in which a special detector is provided in the upper thread guide path for detecting the upper thread tension, in a simple manner keeping the space around the arm area free or ensuring simple assembly, allowing greater freedom of design for the design of the sewing machine head.

Embodiment 2

A configuration and functionality of a sewing machine 100 according to Embodiment 2, referring to FIG 14th described. 14th FIG. 13 is a timing chart illustrating the operation of the sewing machine in accordance with Embodiment 2. FIG.

The sewing machine 100 according to embodiment 2 is different from the sewing machine 100 according to embodiment 1 by the drive curve courses of the holding device 112 in the X-axis direction and in the Y-axis direction by the XY table included in the transport device P1 111 is driven. The rest of the configuration and functionality corresponds to that of the sewing machine 100 according to Embodiment 1. Descriptions of similar parts will be omitted.

Since the XY table described above 111 of Embodiment 1, the X-axis motor 113 between time e and time i, the holding device must 112 when the main shaft motor 134 is operated at high speed and the sewing time for one stitch is short or when the travel distance L of the XY table 111 is large, can be driven at high speed and high accuracy. In order to achieve high speed and high accuracy of the XY table, the rigidity of the mechanism must be improved and the power of the drive source must be increased, resulting in an increased cost. In the present embodiment, the drive type of the holder became 112 changed as follows.

As in the upper part of 14th shown begins the holding device 122 the movement with the X-axis motor 113 as a drive source in the sewing process of the (N-1) -th stitch at the time e and stops the movement of the N-th stitch at the time b 'at which it stops. Hence the X-axis motor 113 stopped in the (N-1) -th stitch during the time period ts from the point in time b to the point in time e and rotates during the time period tm from the point in time e to the point in time b 'at the N-th stitch. The time at which the holding device 122 lasts, can be within the period from time e to time b.

Also shows the lower part of 14th a position profile of the holding device 122 taken from the Y-axis motor 114 is driven in the direction of the Y-axis. The Y-axis motor 114 rotates during the time tm in which the X-axis motor is also rotating 113 turns.

Because the sewing machine 100 according to Embodiment 2, the drive time of the X-axis motor 113 and the Y-axis motor 114 can extend through the upper thread over the central foot 135 on the central foot motor 136 force exerted even at high speed of the main shaft motor 134 and short sewing time of a stitch or with a large traverse path L of the XY table 111 are recorded. That's why the sewing machine can 100 according to Embodiment 2, even in such a case, the change in the by lifting the small hole 133a Detect the upper thread tension exerted on the upper thread with each stitch and form a seam, while at the same time the sewing quality, such as the thread tension or the tightening accuracy, which can determine the quality, is ensured on the basis of the change in the upper thread tension.

Embodiment 3

A configuration and functionality of a sewing machine 100 according to Embodiment 3, referring to FIG 15A , 15B and 16 described. the 15A and 15B are views showing a result of a tension detection operation of the sewing machine according to Embodiment 3. FIG. 16 FIG. 13 is a timing chart illustrating the operation of the sewing machine in accordance with Embodiment 3. FIG.

The sewing machine 100 according to embodiment 3 is different from a sewing machine 100 according to embodiment 1 or 2 by the drive courses of the XY table contained in the transport device P1 111 powered holding device 112 in the direction of the X-axis and in the direction of the Y-axis, the other configurations and functions corresponding to those of a sewing machine 1 according to Embodiment 1 or 2. A description of similar parts is omitted.

First there is a problem with the sewing machine 100 is to be solved according to the present embodiment, based on the 15A and 15B described. In the present embodiment, it is assumed that the diameter of the sewing needle 131 and the upper thread T is larger than Embodiments 1 and 2 described above. Therefore, the diameters of the sewing needle are 131 and the upper thread T in 15A and 15B larger than in 7th and 8th shown, where also the radius r of the through hole 135a of the central foot 135 is shown larger.

15A and 15B illustrate a state at time a 'when the sewing needle 131 located at the top dead center when the sewing machine 100 on the basis of the time course described above for embodiment 1 ( 10 ) is controlled. There in 15A the radius r of the through hole 135a is smaller than the travel L of the XY table, the upper thread comes T with a drive of the XY table with the in the time diagram of 10 shown progression patterns for the X-axis direction and Y-axis direction at time a 'without problems with the central foot 135 in contact. Therefore, in 15A those through the upper thread T when lifting the small hole 133a of the take-up lever 133 over the central foot 135 on the central foot motor 136 The force exerted can be detected on the basis of the LF shaft motor control signal.

There in 15B however, if the radius r is greater than the travel distance L, the upper thread can T even if the holding device 122 with the in the time diagrams of the 10 and 14th is driven in the X-axis direction and Y-axis direction when the small hole is raised 133a not with the underside of the central foot 135 get in touch. Around the upper thread T with the underside of the central foot 135 To bring into contact, a central foot should be used in which the radius r of the through hole 135a is minimized; Keeping several types of central foot ready and replacing a central foot with a central foot with the thickness of the sewing needle 131 and the upper thread T However, the corresponding smallest radius r is not efficient, so that there is a restriction on using a central base with the smallest radius r in each case. In the present embodiment, the drive pattern of the XY table is changed as follows.

As in the upper part of 16 illustrated by a solid line, the holding device begins 122 , as the holding device 122 with the X-axis motor 113 forms a seam as the drive source for the N-th stitch, to move the (N-1) -th stitch from time e in the direction of the X-axis during the transport process, the movement ends when time i is reached and stops. At this point in time, the traveled distance lxx is greater than the radius r of the through hole 135a so that the angle θ obtained by Equation 3 becomes 30 degrees or less. $$\theta =\text{arctan}\left(\frac{dlO}{lxx-r}\right)$$

As the holding device 122 during a period tss from time i to time h 'at which the small hole 133a of the take-up lever 133 is lifted, is stopped, the holding device holds 122 the sewing material If then so that the upper thread T with the underside of the central foot 135 comes into contact. In addition, the holding device moves 122 during a period from time h 'when the small hole is raised 133a is finished until the time b 'at which the sewing needle 131 into the sewing material If is inserted to a predetermined position where the seam on the Nth stitch will be formed. Then the holding device 122 during a period ts from time b 'at which the sewing needle 131 into the sewing material If is introduced until the time e 'at which the sewing needle 131 is withdrawn, stopped. After the point in time e ', the same process for forming the (N + 1) seam is carried out repeatedly.

The thick line in the lower part of 16 illustrates a drive course of the holding device 122 in the Y-axis direction with the Y-axis motor 114 as a drive source. In this figure shows the Y-axis motor 114 the same drive path as the X-axis motor.

Since the seams of the (N-1) th stitch and the N th stitch are separated in the X-axis direction by lx and in the Y-axis direction by ly, the distance to be covered from time h 'to time b' is in X- Axis direction (lxx-lx) and the Y-axis direction (lyy-ly), and the travel distance L2 of the XY table can be obtained by Equation 4. $$\mathrm{L.}2=\sqrt{{\left(lxx-lx\right)}^2+{\left(lyy-ly\right)}^2}$$

When the travel lxx in the X-axis direction compared with the radius r of the through hole 135a is sufficiently large, the course of motion lyy can be set to ly, since it is not necessary to change the course of the drive of the Y-axis motor. In other words, lxx and lyy can be set so that the distance L2 obtained by equation 5 is sufficiently large compared to the radius r. $$\mathrm{L.}2=\sqrt{lx{x}^2+ly{y}^2}$$

In addition, the period from time e to time i becomes when the main shaft motor is rotating at high speed 134 and short sewing time for a stitch or with a large travel distance L of the XY table 111 shortly. Like the thick dashed line in 16 shows, therefore, when the upper thread T with the underside of the central foot 135 comes into contact, the time at which the holding device 122 is stopped within the period from time e to time h '.

At the sewing machine 100 according to embodiment 3, due to the thickness of the sewing needle 131 or the upper thread T even if the radius r of the through hole 135a of the central foot 135 is greater than the stitch length, the holding device 122 during the period in which the small hole 133a is raised, driven so that the upper thread T with the underside of the central foot 135 comes into contact. That's why the sewing machine can 100 According to Embodiment 3, even in such a case, with each stitch, the change in the by lifting the small hole 133a Detect the upper thread tension applied to the upper thread and form a seam, while at the same time the sewing quality, such as the thread tension or the tightening accuracy, which determine the quality, is guaranteed on the basis of the change in the upper thread tension.

In addition, in the present embodiment, it is assumed that the through hole 135a of the central foot 135 has a circular bottom with the radius r, but also when using a central foot, the bottom of the through hole 135a is not circular, the quality can be ensured on the basis of the upper thread tension detection unit according to the invention.

Embodiment 4

A configuration and functionality of a sewing machine 100 according to Embodiment 4, referring to FIG 17th and 18th described. 17th FIG. 13 is a block diagram showing details of the LF shaft motor control calculation unit of the sewing machine according to Embodiment 4. FIG. 18th FIG. 13 is a block diagram showing details of the LF wave deviation suppressing unit of the sewing machine according to Embodiment 4. FIG.

The sewing machine 100 according to embodiment 4 is different from a sewing machine 100 according to the embodiments 1 to 3 by the in the memory 121c the control console 121 data to be stored and by the LF wave deviation suppressing unit 1B3a of the operation panel 122B, the other configurations and functions being those of a sewing machine 100 according to embodiments 1 to 3 correspond. A description of similar parts is omitted.

With reference to 17th describes the data that is between the control panel 121 and the control panel 121B of the sewing machine 100 are transferred according to execution 4. The storage device 121c the control console 121 stores one from the sewing machine user 100 with the input device 121d inputs parameter D2 and outputs parameter D2 to control panel 122B. The parameter D2 is transmitted via a communication circuit (not shown) on the basis of an instruction of the in the control panel 121 included processor 121b to control console 122B. The LF wave deviation suppressing unit 1B3a of the control panel 122B receives the parameter D2 and changes the control parameters in the LF wave deviation suppressing unit 1B3a.

Next, referring to FIG 18th Details of the LF wave deviation suppressing unit 1B3a will be described. The LF shaft deviation suppressing unit 1B3a receives the LF shaft instruction signal, the LF shaft rotation signal, the voltage monitor signal and the parameter D2 as inputs and outputs the LF shaft motor drive signal. The deviation suppression compensator a3 of the LF wave deviation suppressing unit 1B3a controls the rotation of the central foot motor 136 so that the difference between the LF shaft instruction signal and the LF shaft rotation signal becomes zero. When the deviation suppression compensator a3 in 18th is set up as a PI controller by the proportional compensator and the integral compensator and is the deviation signal Se and the LF shaft motor drive signal Sd, the transfer function of the deviation suppression compensator can be expressed by Equation 6. $$\frac{\mathrm{S.}d}{\mathrm{S.}e}=kp\left(\frac{1+Ti\cdot s}{Ti\cdot s}\right)$$

Here, the symbol kp denotes a gain of the proportional controller, the symbol Ti denotes an integration time constant and the symbol s denotes a Laplace operator. The values of kp and Ti, which are control parameters within the LF wave deviation suppressing unit 1B3a, are changed based on the parameter D2 input from the outside.

Specifically, the parameter D2 influences the amplitude of the deviation signal Se by changing the gain kp of the proportional controller or the amplitude and phase of the deviation signal Se by changing the integration time constant Ti. In a sewing machine 100 according to the present embodiment changes during the period of time from when the gripper 132 the caught upper thread T releases, until the point in time when the small hole 113a by operating the thread lever 133 is raised, ie a period of time in which there is the possibility that the central foot 135 of the sewing material If is lifted off and with the upper thread T comes into contact, based on the Parameter D2 adjust the gain kp of the proportional controller so that it becomes small, or the integration time constant Ti such that it becomes long.

There by the sewing machine 100 According to Embodiment 4, based on the parameter D2, the gain kp of the proportional controller is set to be small or the integration time constant Ti is set to be long, the response to the external force generated during the period in which the upper thread T with the central foot 135 comes into contact on the central foot motor 136 acts, be slowed down. This can reduce the frictional force between the upper thread T and the central foot 135 arises when the upper thread T using the central foot 135 as the pivot point is raised, be decreased. Therefore, the LF wave deviation suppressing unit 1B3a of the sewing machine 100 according to the present embodiment the central foot motor 136 drive and at the same time prevent the upper thread T when detecting the upper thread tension through the frictional force on the central foot 135 cut off or torn.

Every function of the control panel of a sewing machine 100 according to Embodiments 1 to 4 can be realized using a processing circuit. Under each function are the instruction generation unit 1A1 and the LF shaft motor control calculation unit 1A3 to understand. The view of 19th FIG. 11 illustrates a first hardware configuration example of the control panel of a sewing machine according to Embodiments 1 to 4. The view of FIG 20th FIG. 11 illustrates a second hardware configuration example of the control panel of a sewing machine according to Embodiments 1 to 4. FIG. 19th Fig. 10 shows an example in which the processing circuit described above is operated by a specialized hardware such as a special processing circuit 190 , is implemented. 20th FIG. 10 shows an example in which the processing circuit described above is implemented using a processor 191 and a memory device 192.

If the in 18th If the special hardware illustrated is used, the specialized processing circuitry corresponds 190 a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or any combination of these, if applicable. Each of the above functions can be implemented using a processing circuit, but the above functions can also be implemented collectively by a processing circuit. When the processor 191 and storage device 192 shown in 20th are used, each of the above functions is implemented by software, firmware, or a combination of software and firmware. Software or firmware are described as programs and are stored in the storage device 192. The processor 191 reads the program stored in the storage device 192 and executes it. Needless to say, these programs cause a computer to carry out a procedure or method carried out by the above functions. The memory device 192 corresponds to a semiconductor memory such as a random access memory (RAM), a read-only memory (ROM), a flash memory, an erasable programmable read-only memory (EPROM (registered trademark)) or an electrically erasable programmable read-only memory (EEPROM). The semiconductor memory can be a non-volatile memory or a volatile memory. In addition to the semiconductor memory, the storage device 192 can be a magnetic disk, a floppy disk, an optical disk, a compact disk, a mini disk, or a digital versatile disk (DVD).

In the configuration described in the embodiments described above, the one from the upper thread to the central foot 135 Detected force exerted on the basis of the LF shaft motor drive signal, but the present invention is not limited to this, wherein a detection element for detecting the on the central foot 135 exerted force in the central foot drive mechanism 151 can be provided.

List of reference symbols

100

sewing machine

101

poor

102

Main shaft motor housing

103

head

104

Substructure

105

Support leg

106

Sliding plate

111

XY table

112

Holding device

112a

Transport plate

112b

upper pusher

112c

Pressure bar

112d

pneumatic cylinder

113

X-axis motor

114

Y-axis motor

115

X-axis drive mechanism

115a

movable slide

116

Y-axis drive mechanism

116a

Y-axis guidance

117, 118, 137, 150

Rotation information detector

121

Control console

121a

Display

121b, 191

processor

121c, 192

Storage device

D1

Sewing pattern data

121d

Input device

122, 122A

Control console

123

Foot switch

1A1

Instruction generation unit

1A2

Main shaft motor control calculation unit

1A3

LF shaft motor control calculation unit

1A4

X-axis motor control calculation unit

1A5

Y-axis motor control calculation unit

131, 131 '

Sewing needle

131a, 131a '

Eye of a needle

132

Grapple

133

Take-up lever

133a, 131a '

small hole

134

Main shaft motor

135, 135 '

Central foot

135a, 135a '

Through hole

136

Central foot motor

138

coupling

139

upper shaft

140

Take-up lever drive mechanism

141

Needle bar drive mechanism

142

Needle bar

143

Bobbin case

144

Pulley for the upper shaft

145

Timing belt

146

Belt pulley for the lower shaft

147

Large diameter gear

148

Small diameter gear

149

lower shaft

151

Central foot drive mechanism

152

pinion

153

Rack

154

Sliding guide

155

runner

156

Central foot bar holder

157

Central foot bar

158

Bobbin rack

159

Kitchen sink

160, 161, 164, 165, 166

Upper thread guide

162

Thread pretensioner

163

Main thread tensioner

190

specialized processing circuit

a1

counter

a2

Differentiator

a3

Deviation suppression compensator

c1

Filter processing unit

c2

Recording unit

c3

Comparator

T, T '

Upper thread

Td, Td '

Bobbin thread

Whether, whether '

Sewing material

Claims (11)

A sewing machine (100) comprising: a looper (132) which links an upper thread (T, T ') and a lower thread (Td, Td') to one another by pulling the upper thread ( T, T ') catches; a thread lever (133) which has a small hole (113a) through which the upper thread (T, T ') is guided, and which removes the upper thread (T, T') from a sewing material (Ob, Ob '), in which it is an object to be sewn, lifts, by raising the small hole (113a) from a lower turning point to an upper turning point; a central foot (135, 135 ') which prevents the sewing material (Ob, Ob') from being lifted; a drive source (136) that drives the central foot (135, 135 '); a transport unit (P1) which transports the sewing material (Ob, Ob '); and a tension monitoring unit (1A3c) which monitors an upper thread tension on the basis of a force exerted by the upper thread (T, T ') on the central foot (135, 135') by the central foot (135, 135 ') being transported during the transport of the sewing material (Ob, Ob ') is brought into contact with the upper thread (T, T') by the transport unit (P1). Sewing machine (100) Claim 1 wherein the tension monitoring unit (1A3c) detects the upper thread tension on the basis of the force applied to the drive source (136). Sewing machine (100) Claim 1 or 2 , wherein the tension monitoring unit (1A3c) the upper thread tension for a period of time from the time at which the looper (132) releases the captured upper thread (T, T ') to the time at which the small hole (113a) the top dead center reached, monitored. Sewing machine (100) according to one of the Claims 1 until 3 , wherein the tension monitoring unit (1A3c) outputs a sewing error signal for reporting a sewing error if the upper thread tension is greater or less than a reference value entered from outside. Sewing machine (100) according to one of the Claims 1 until 3 wherein the tension monitoring unit (1A3c) has a recording unit (c2) which records the upper thread tension for each stitch and outputs a sewing error signal for reporting a sewing error if a change in the upper thread tension for a respective stitch is greater or less than an externally input reference value. Sewing machine (100) according to one of the Claims 1 until 3 wherein the tension monitoring unit (1A3c) comprises a recording unit (c2) which records the upper thread tension with each stitch and outputs a sewing error signal for reporting a sewing error when the difference between the upper thread tension recorded by the recording unit (c2) and that of the tension monitoring unit (1A3c ) monitored upper thread tension is greater than a preset threshold value. Sewing machine (100) according to one of the Claims 1 until 6th which further comprises: an instruction generation unit (1A1) which generates a control instruction for the drive source (136) for stopping the central foot (135, 135 ') at a certain height above the sewing material (Ob, Ob') during a period of time from the point in time at which the looper (132) releases the caught upper thread (T, T '), up to the point in time at which the small hole (113a) is raised. Sewing machine (100) Claim 7 further comprising: a deviation suppressing unit (1B3a) that controls the drive source (136) so that a deviation signal obtained by the difference between a drive state of the drive source (136) and the driving instruction becomes zero with a gain of a proportional calculator influences an amplitude of the deviation signal based on a parameter inputted from outside the deviation suppressing unit (1B3a) during a period from when the looper (132) releases the caught upper thread (T, T ') to the time where the small hole (113a) is raised by the operation of the thread take-up lever (133). Sewing machine (100) Claim 7 further comprising: a deviation suppressing unit (1B3a) that controls the drive source (136) so that a deviation signal obtained by the difference between a drive state of the drive source (136) and the drive instruction becomes zero, wherein an integration time constant of an integration calculator an amplitude and phase of the deviation signal based on a parameter inputted from outside the deviation suppressing unit (1B3a) during a period from when the looper (132) releases the caught upper thread (T, T ') to Time at which the small hole (113a) is raised by the operation of the thread take-up lever (133). Sewing machine (100) according to one of the Claims 1 until 9 , where, if based on the voltage monitoring unit (1A3c) monitored needle thread tension a sewing error is detected, the central foot (135, 135 '), or the sewing needle (131, 131'), the hook (132), the thread lever (133), the central foot (135, 135 ') and the transport unit ( P1) are stopped. Sewing machine (100) according to one of the Claims 1 until 10 which further comprises: a display (121a) which, when a sewing error is detected, on the basis of the upper thread tension monitored by the tension monitoring unit (1A3c), indicates that a sewing error has occurred.

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