sewing machine

Abstract

Sewing machine (100), comprising: a sewing needle (11) having an eye through which a needle thread is inserted; a shuttle (12) including a point for grasping the needle thread in order to interlace the needle thread and a bobbin thread; a thread take-up lever (13) having a small hole (122) through which the needle thread is inserted, the thread take-up lever (13) lifting the needle thread from a sewn object, which is a sewing target, in accordance with the rise of the small hole (122) from a bottom dead center to a top dead center; a central pusher (15) to prevent the sewn object from floating; and a drive source to drive the central pusher (15) in such a way that the central pusher (15) is stopped at a fixed height during a period in which the small hole (122) rises in accordance with an operation of the thread lever (13) after the needle thread caught by the shuttle (12) has been released.

Description

Area

[0001] The present invention relates to a sewing machine including a sewing needle, a shuttle, a thread take-up lever and a center presser. background

[0002] In conventional sewing machines which perform sewing while feeding a sewn article such as cloth or leather in a plane perpendicular to a sewing needle, a center presser is provided. The center pusher presses down on the periphery of a needle piercing portion of the sewn object during raising and lowering of the sewing needle to prevent the sewn object from rising and rising and fluttering together with the sewing needle due to friction between the sewn object and the sewing needle.

[0003] A sewing machine disclosed in Patent Literature 1 includes a second drive source separate from a first drive source that moves the center presser, which presses down on a sewn object, up and down in parallel with the sewing needle and changes the height of the center presser during sewing . The first drive source moves the sewing needle and the center presser up and down. The second drive source varies the amplitude of the up and down movement of the center pusher, which is driven along a sinusoidal path with respect to the angle of rotation of the first drive source. The second drive source can change the amplitude of the up and down movement of the center pusher by applying height change control to change the height of the top dead center or the bottom dead center of the center pusher.

[0004] Specifically, a motor is used as the second drive source of the sewing machine disclosed in Patent Literature 1. The height change control of the center pusher is performed by controlling the rotation of the motor. In the sewing machine disclosed in Patent Literature 1, the first drive source is driven so as to adjust the bottom dead center height of the center presser to be lower than the top of a slide plate that functions as a stand when the sewn object is moved by a positioning unit is transported. When the center presser is lowered and comes into contact with the sewn object and a torque disturbance is applied to the output shaft of the motor, the second drive source controls the center presser to rise. As a result, in the sewing machine disclosed in Patent Literature 1, the downward force of the center presser due to the first drive source, an elastic force of a spring that constantly presses down the center presser when the center presser moves up and down in synchronism with the sewing needle, and balanced the rising force of the center pusher due to the second drive source. Consequently, the height of the central pusher can be controlled.

[0005] The sewing machine disclosed in Patent Literature 1 is designed to move the sewing needle up and down in one cycle while the rotation angle of the motor, which is the first driving source for driving the sewing needle, is once from 0° to 360° turns. In one cycle of the sewing needle, the center presser is driven so as to be at top dead center when the rotation angle of the motor, which is the first drive source for driving the sewing needle, is 0°, and so as to be is at bottom dead center when the rotation angle is 180°. The central presser of the sewing machine disclosed in Patent Literature 1 usually presses the sewn object during the period from when the central presser comes into contact with the sewn object to when the sewing needle reaches the bottom dead center down. In this way, in the sewing machine disclosed in Patent Literature 1, the center presser usually presses down on the sewn object during the period in which the motor, which is the first drive source, rotates from 0° to 180°. However, from Patent Literature 1, even if the rotation of the motor exceeds 180°, fine adjustment can be performed in a range up to about 190°, for example.

[0006] Some general sewing machines with a feeder include a cloth pressing device as disclosed in Patent Literature 2 or Patent Literature 3 . Patent Literature 2 discloses a cloth pressing device of a sewing machine, including a press rod that moves up and down in association with the rotation of the spindle motor of the sewing machine; a cloth pressing unit supported at the lower end of the presser bar so as to be slidable in the axial direction of the presser bar; an urging unit that applies an urging force to press down the cloth pressing unit with respect to a frame; a presser bar driving unit that drives the presser bar such that the presser bar presses down on a sewn object at least when a needle moves up from the bottom dead center and a tip of a shuttle picks up a needle thread; and a height changing device which can change the height at which the cloth pressing unit is held and which can change the urging force applied to the cloth pressing unit. Patent Literature 2 discloses a structure in which the cloth pressing device is driven in the up-down direction by a servo motor. Patent Literature 3 discloses a sewing machine capable of changing the up and down stroke of a presser or the timings of raising and lowering of the presser with respect to a sewing needle by using a presser driving mechanism driven by a motor, which is different from the spindle motor that drives the sewing needle. In the sewing machine with the presser drive mechanism, vibration and noise during sewing can be reduced by changing the drive of the motor, which causes the presser to rise and rise, in accordance with the status of the sewing process or the properties of the material of the sewn object to lower. Patent Literature 3 discloses a scheme for driving the presser so as to reach the bottom dead center during a period from before the sewing needle is inserted into the sewn object to until the sewing needle is pulled out of the sewn object achieved. List of Documents CitedPatent Literature Patent Literature 1: Japanese Patent Application Laid-Open No. 2010-148551 Patent Literature 2: Japanese Patent Application Laid-Open No. H8-38763 Patent Literature 3: Japanese Patent Application Laid-Open No. H11-128576 AbstractTechnical issue

[0007] The sewing machine disclosed in Patent Literature 1 causes the center presser to descend to adjust the bottom dead center height of the center presser to be lower than the top of the slide plate. When the center presser comes into contact with the sewn object and thus a disturbance torque is applied to the rotary shaft of the motor that drives the center presser, the sewing machine adjusts the height of the center presser so that the center presser moves up. Consequently, the sewing machine disclosed in Patent Literature 1 can change the heights of the bottom dead center and the top dead center of the center presser to a given height, and can change the operation amplitude of the center presser even when the sewing machine sews. Since the sewing machine causes the center presser to descend to adjust the bottom dead point height of the center presser to be lower than the top of the slide plate, it is possible to avoid a situation where the center presser goes up returns before the second power source, which adjusts the height of the center pusher, is operational.

[0008] However, in the sewing machine disclosed in Patent Literature 1, both the sewing needle and the center presser move up and down in unison with the first driving source; therefore, it is difficult to change the up and down movement of the center presser such that the center presser presses down on the sewn object at a given timing with a phase largely shifted from the movement of the sewing needle, the center presser e.g. during a long period of time before the sewing needle is inserted into the sewn object until the sewing needle is pulled out of the sewn object, or the sewing needle continues to press down on the sewn object for a long period of time even after the sewing needle is pulled out of the sewn object .

[0009] For example, the bottom dead point of the center presser can be finely adjusted up to about 190° when the rotation angle of the motor, which is the first drive source driving the sewing needle, exceeds 180°. In order to set the bottom dead point of the center pusher outside of this range, a mechanism for transmitting a driving force of the first drive source to the center pusher must be mechanically adjusted. Unless mechanical adjustment or change is made, the center presser cannot press down on the sewn object when the rotation angle of the motor, which is the first driving source, exceeds 190°. This means that the central presser cannot press down on the sewn object with a rotation angle beyond 190°, while a thread lever rises from the bottom dead center to the top dead center. As a result, the sewing machine disclosed in Patent Literature 1 has a problem that, particularly when a seam is formed in a sewn article that is stretchable, the seam tightening effect exerted by the thread take-up lever is uneven or insufficient at each stitch in some cases.

[0010] The cloth pressing device of the sewing machine disclosed in Patent Literature 2 includes the urging unit that applies an urging force to the cloth pressing unit to urge the pressing unit down, and the height changing device that can change the holding height of the cloth pressing unit and change the urging force exerted on the cloth pressing unit. With such a structure, if the bottom dead center of the cloth pressing unit is set higher than the surface of the frame, even if the sewn object is hard, collision between the frame and the cloth pressing unit can be avoided, and the noise during sewing can be reduced. The cloth pressing device of the sewing machine disclosed in Patent Literature 2 presses down the sewn object when the needle moves up from the bottom dead center and the tip of the shuttle picks up the needle thread. In this way, it is possible to reduce the rate of occurrence of stitch skipping, which is a phenomenon in which the tip of the shuttle cannot catch the needle thread and a seam is not formed. However, in the sewing machine with the cloth pressing device disclosed in Patent Literature 2, the sewn object is likely to flutter while the thread take-up lever rises from the bottom dead center to the top dead center. As a result, in the patent literature 2, as in the patent literature 1, there is a problem that the seam tightening effect exerted by the thread take-up lever is uneven or insufficient in each stitch in some cases.

[0011] The sewing machine with the cloth pressing device disclosed in Patent Literature 3 presses down the sewn object in a cycle of up and down movement of the needle bar during the period from before the sewing needle is inserted into the sewn object until the sewing needle is withdrawn from the sewn object. In this way, the cloth pressing device disclosed in Patent Literature 3 can reduce the rate of occurrence of the stitch skipping described above. The presser device disclosed in Patent Literature 3 can reduce vibration and noise during sewing by changing the driving of the motor that causes the presser to rise and fall in accordance with the status of sewing or the properties of the material of the sewn object . However, in the sewing machine with the cloth pressing device disclosed in Patent Literature 3, the sewn object is likely to flutter while the thread take-up lever rises from the bottom dead center to the top dead center. As a result, the patent literature 3, like the patent literatures 1 and 2, has a problem that the seam tightening effect exerted by the thread take-up lever is uneven or insufficient in some cases. As explained above, the center pushers disclosed in the patent references are mainly used to reduce the rate of occurrence of stitch skipping and are not used to improve the seam tightening performed by the thread take-up lever. In the patent literatures, damage to the sewn object and vibration and noise during sewing are reduced by changing the operation of the center presser by using a driving source different from the driving source for the sewing needle.

[0012] The present invention has been made in view of the foregoing, and a purpose of the present invention is to provide a sewing machine which can improve seam tightness of a seam formed in a sewn article. the solution of the problem

[0013] In order to solve the above problems and achieve the purpose, a sewing machine according to an aspect of the present invention includes: a sewing needle having a needle eye through which a needle thread is inserted; a shuttle including a tip for grasping the needle thread to interlace the needle thread and a bobbin thread; a thread take-up lever having a small hole through which the needle thread is inserted, the thread take-up lever drawing the needle thread from a sewn object, which is a sewing target, in accordance with the rise of the small hole from a bottom dead center to an upper one dead center lifts; a center presser to prevent the sewn object from floating; and a drive source for driving the center presser such that the center presser is stopped at a fixed height during a period in which the small hole rises in accordance with an operation of the thread take-up lever after the needle thread caught by the shuttle is released. Advantageous Effects of the Invention

[0014] According to the present invention, an effect is obtained by which it is possible to improve seam tightness of a seam formed in a sewn article. character list figure 1 is a perspective view showing an overall structure of a sewing machine according to a first embodiment. figure 2 is a perspective view showing the construction of a sewing mechanism of the sewing machine according to the first embodiment. figure 3 is a perspective view showing the structure of a driving mechanism of the center presser of the sewing machine according to the first embodiment. figure 4 is a perspective view showing the structure of a feeding mechanism of the sewing machine according to the first embodiment. figure 5 is a block diagram showing a control structure of the sewing machine according to the first embodiment. figure 6 is a time chart when the sewing machine according to the first embodiment is operated with a conventional drive pattern. figure 7 is a time chart when the sewing machine according to the first embodiment is operated with a drive pattern according to the present invention. figure 8 is a timing chart showing a driving pattern of a sewing machine according to the second embodiment. figure 9 is a block diagram showing a control structure of a control panel of a sewing machine according to a third embodiment. figure 10 is an operation diagram of a center presser of the sewing machine according to the third embodiment. Description of Embodiments

[0015] Hereinafter, a sewing machine according to embodiments of the present invention will be explained in detail with reference to the drawings. The present invention is not limited by the embodiments. First embodiment.

[0016] In a first embodiment, a sewing machine including a holding device that holds a sewn object, which is a sewing material such as cloth or leather, will be described as an example. In the sewing machine, the sewn object is fed with respect to a sewing needle by the holding device, whereby a seam is formed in the sewn object at a predetermined predetermined position. In order to simplify the explanation, in the first embodiment, a case where a seam is formed in a sewn article that is not stretchable will be described.

[0017] First, the construction of the sewing machine according to the first embodiment will be explained with reference to FIG figure 1 to figure 4 explained. figure 1 is a perspective view showing an overall structure of the sewing machine according to the first embodiment. figure 2 is a perspective view showing the structure of a sewing mechanism of the sewing machine according to the first embodiment. figure 3 is a perspective view showing the structure of a driving mechanism of the center presser of the sewing machine according to the first embodiment. figure4 is a perspective view showing the structure of a feeding mechanism of the sewing machine according to the first embodiment. In figure 1 to figure 4, a direction in which a sewing needle moves up and down is shown as a Z-axis direction or up-down direction, a direction perpendicular to the Z-axis direction is shown as an X-axis direction, and a Direction perpendicular to both the Z-axis direction and the X-axis direction is represented as the Y-axis direction. The X-axis direction is the longitudinal direction of a bed 2 , which will be explained later. [overall structure]

[0018] The main part of an in figure 1 shown sewing machine 100 is made of a housing mechanism P0 , a sewing mechanism P1 , a feeding mechanism P2 and a control device P3 built up. [housing mechanism P0]

[0019] The housing mechanism P0 includes an arm 1 , in which a drive source of the sewing mechanism P1 is provided; the bed 2 , in which a drive source of the feeding mechanism P2 is provided; a support leg 3 , which the bed 2 supports starting from the ground surface; and a skid plate 4 , which is a frame that attaches to the top of the bed 2 is attached. The case mechanism P0 is constructed of a fabricated material such as steel plate or cast body with high rigidity, which is designed to withstand mechanical breakage due to impact during operation of the sewing machine 100 to withstand. [Sewing Mechanism P1]

[0020] The sewing mechanism P1 includes a sewing needle 11 ; a boat 12 ; a thread lever 13 ; a spindle motor 14 , which is a driving source; a center button 15 ; an engine 16 the central pusher; and a thread tension adjuster 17 . The sewing mechanism P1 Executes sewing to sew a stitch in a sewn item on the slide plate 4 to build. [Feeding Mechanism P2]

[0021] The feeding mechanism P2 includes an X-axis motor 21 , a Y-axis motor 22 , an X-axis drive mechanism 23 , a Y-axis drive mechanism 24 , a sled 25 , a holding device 26 , a rotation information detector 27 and a rotation information detector 28 .

[0022] The feeding mechanism P2 holds the sewn item with the holding device 26 who are on the trolley 25 is fixed, which is a movable portion of the feeding mechanism P2 acts, so that a needle insertion position of the sewing needle 11 into the sewn object at a predetermined position on a horizontal plane perpendicular to the up and down movement of the sewing needle 11 located. The feeding mechanism P2 performs a feeding operation to move the sewn object in the X-axis direction and the Y-axis direction on the slide plate 4 to move. [Control device P3]

[0023] The control device P3 includes a control panel 31 , a control panel 32A and a footswitch 33 . The control panel 31 generated based on sewing pattern data D1 and sewing print data D2 made by a user of the sewing machine 100 showing the control panel 31 operated, a sewing command signal for driving the sewing machine 100 , and the control panel 31 then sends the sewing command signal to the control panel 32A . The Control Panel 32A controls the operating speed and time of sewing by the sewing mechanism P1 and controls the operating speed and the time of the transporting work by the feeding mechanism P2 . In response to the user of the sewing machine 100 performed operation of pressing a button or a touch pad is the footswitch33 The following into the control panel 32A on: an operation start signal showing the time of start of control of the sewing machine 100 and a hold signal indicating the time of performing the switching between holding and releasing the sewn object by the holding device 26 indicates. [Sewing Mechanism P1]

[0024] Details of the sewing mechanism P1 the sewing machine 100 according to the first embodiment are described with reference to FIG figure 2 explained. As in figure 2 includes the sewing mechanism P1 the sewing needle 11 , which has a needle eye; the boat 12 that includes a tip that grasps a needle thread and intertwines the needle thread and a bobbin thread; the thread lever 13 that performs seam tightening of a seam formed in the sewn object, the spindle motor 14 , which is a first drive source of the sewing machine 100 acts; the middle button 15 , pressing down on the sewn object; and the engine 16 of the center presser, which is a second drive source of the sewing machine 100 acts. In addition to these components includes the sewing mechanism P1 Components such as the thread tension adjuster 17 , which adjusts the tension of the needle thread, and a rotation information detector 18 . However, these components have no direct influence on the effect of the present invention; therefore, a description of these components is omitted. [Sewing Needle 11]

[0025] The sewing needle 11 has an eye of the needle through which the needle thread is threaded, which becomes the thread on the upper side when the seam is formed, making up and down movement by driving the spindle motor 14 used as a power source. The sewing needle 11 reaches the bottom dead center after being lowered from the top dead center and inserted into the sewn object. Then the sewing needle 11 pulled out from the sewn object while rising from the bottom dead center toward the top dead center. After reaching the bottom dead center, the sewing needle acts 11 with the boat 12 together until pulled out of the sewn object to interlace the needle thread and the bobbin thread, which becomes the thread on the lower side of the sewn object when the seam is formed. Then the eye of the needle becomes the sewing needle 11 pulled out of the sewn object, thereby pulling the needle thread to the top of the sewn object.

[0026] The rotation information detector 18 is on the spindle motor 14 attached to the the sewing needle 11 drives. The rotation information detector 18 detects information such as an angle, an angular velocity and an angular acceleration of the rotor with respect to the stator of the motor. In the first embodiment, the rotation information detector 18 described as an optical encoder that detects the angle of the rotor with respect to the stator. The Spindle Motor 14 is on the arm 1 fastened. One end of a shaft shaped upper shaft 19 is via a coupling 110 to the rotor of the spindle motor 14 coupled. The rotation of the upper shaft 19 is in the translational movement of a shaft-shaped needle bar 115 converted to a needle bar connecting pivot 114 is fixed, via a crank 111 that at the other end of the upper shaft 19 attached to which the coupling 110 is not paired; a needle bar crank 112 ; and a connecting rod 113 . The sewing needle 11 is at the distal end of the needle bar 115 appropriate. The sewing needle 11 moves in an up-down direction in unison with the up-down movement of the needle bar 115 . A mechanism for driving the needle bar 115is a well known technology; therefore, an explanation of the mechanism referring to an enlarged view is omitted. [Shuttle 12]

[0027] In the first embodiment, a full rotation shuttle is used as the shuttle 12 used. The boat 12 however, is not limited to a full turn shuttle. For example, the boat 12 a half-turn shuttle, or it may be a horizontal shuttle or a vertical shuttle. The boat 12 is composed of an outer shuttle containing a tip; a bobbin around which a bobbin thread is wound; and a bobbin case accommodating the bobbin to prevent the bobbin from slipping out of the outer shuttle.

[0028] Near a section where one end of the upper shaft 19 and the coupling 110 coupled together is a pulley 116 of the upper shaft concentric with the upper shaft 19 appropriate. The Pulley 116 the upper shaft on the drive side rotates via a drive belt 117 a pulley 118 the lower shaft on the driven side. The Pulley 118 the lower shaft rotates a large-diameter gear wheel via a shaft 119 , and it rotates a small-diameter gear 120 , the one with the large diameter gear 119 combs. With such a structure, a shaft-shaped lower shaft rotates 121 that with the small diameter gear 120 is coupled at a speed twice the speed of the upper shaft 19 . The boat 12 and the lower shaft 121 are coupled at the shaft end where the small diameter gear 120 not on the lower shaft 121 is attached. If the spindle motor 14 turns, the boat turns 12 at a speed twice as fast as the speed of the up and down movement of the sewing needle 11 . While the sewing needle 11 descends and is inserted into the sewn object, and then rises toward the top dead center after reaching the bottom dead center, catches the tip of the shuttle 12 a ring formed by the needle thread passing through the eye of the sewing needle 11 is introduced. The construction of the full turn shuttle is a well-known technology; therefore, an explanation referring to an enlarged view is omitted. [thread lever 13]

[0029] The thread lever 13 is a rigid body made of a metal material and shaped like a rocker arm. A small hole 122 , through which the needle thread is inserted, is at one end of the thread take-up lever 13 intended. The other end of the take-up lever 13 is rotatable with the crank 111 connected to the upper shaft 19 connected is. One end of a take-up lever rod 123 is rotatable with the arm 1 tied together. The other end of the thread take-up rod 123 is coupled to a bent end of the rocker arm shape. With such a structure, the take-up lever 13 through the upper wave 19 driven, moving synchronously with the spindle motor 14 rotates, causing a cycle of up and down movements of the sewing needle 11 and the thread lever 13 become equal. The little hole 122 the thread lever 13 is usually driven in such a way that it reaches the top dead center when the rotation angle of the spindle motor is 60° from the top dead center of the sewing needle 11 is delayed. The construction of the take-up lever 13 is a well known technology; therefore, an explanation using an enlarged view is omitted. [Central pusher 15]

[0030] A drive mechanism of the central pusher 15 according to the first embodiment, reference is made to FIG figure 3 explained. As in figure3, the driving mechanism of the center pusher is composed of the center pusher 15 ; the engine 16 the central pusher; a rotation information detector 124 working on the engine 16 of the central pusher; a pinion 125 ; a rack 126 ; a sliding guide 127 ; a slide 128 ; a connecting pin 129 for the central pusher bar; and a pole 130 of the central pusher. The rotation information detector 124 , which detects information such as an angle, an angular velocity, and an angular acceleration of the rotor with respect to the stator, is on the motor 16 attached to the central pusher. In the first embodiment, the rotation information detector 124 described as an optical encoder that detects an angle of the rotor with respect to the stator. The motor 16 of the central pusher is a servo motor attached to the arm 1 is attached. A small circular hole is in the center of the sprocket 125 is provided which is a small diameter circular gear with this hole fitting around the rotor. The teeth of the pinion 125 mesh with the teeth of the rack 126 and convert the rotational movement of the rotor of the motor 16 of the central pusher in the translation movement of the rack 126 around. The rack 126 is with the slider 128 coupled by the sliding guide 127 guided to move in the vertical direction. The connecting pin 129 for the central pusher rod is by bolts on the slider 128 fastened. The pole 130 of the central handle is secured by the connecting pin 129 inserted and screwed for the rod of the central handle. The middle pusher 15 is at the distal end of the rod 130 attached to the central pusher. The pole 130 of the center pusher moves in up-down direction, causing the center pusher 15 is driven in the up-down direction.

[0031] In the first embodiment, a rotary-type servomotor, i.e., a rotary electric machine including an annular stator and a columnar rotor, is used as the motor 16 of the central pusher. The rotary movement of the rotor is transformed into the translational movement of the central pusher by means of a rack and pinion 15 converted. The second power source of the sewing machine 100 however, is not limited to a rotary electric machine such as a servo motor or a stepping motor. From a technical standpoint that ignores cost, the second drive source can be a variety of actuators such as linear motors, planar motors, or spherical motors. For example, when using linear motors, it is not necessary to use a conversion mechanism for converting rotation to translational motion. In this way, the structure of a mechanical system can be further simplified. Note that when pressure control of a center pusher to be explained in a third embodiment is performed, it is desirable to use linear motors. This is because when linear motors are used, they do not have non-linear characteristics such as backlash between the rack and pinion. [Feeding Mechanism P2]

[0032] The feeding mechanism P2 the sewing machine 100 according to the first embodiment, reference is made to FIG figure 4 explained. As in figure 4 includes the feed mechanism P2 the X-axis motor 21 ; the Y-axis motor 22 ; the X-axis drive mechanism 23 ; the Y-axis drive mechanism 24 ; the sled 25 ; and the holding device 26 . The feeding mechanism P2 is a positioning unit for feeding the sewn object through the sewing machine 100 .

[0033] The X-axis motor 21 and the Y axis motor 22 , which are power sources of the feeding mechanism P2 are servo motors mounted on the side surface of the bed 2 are attached. The X-axis motor 21 and the Y axis motor 22 drive the X-axis drive mechanism 23 and the Y-axis drive mechanism, respectively 24 on. The running sled 25 is a movable unit driven by the X-axis drive mechanism 23 and the Y-axis driving mechanism 24 is driven. The running sled 25 is perpendicular to the up and down movement of the sewing needle in the X-axis direction and the Y-axis direction in the horizontal plane 11 arranged. The rotation information detector 27 , which detects information such as an angle, an angular velocity, and an angular acceleration of the rotor with respect to the stator, is on the X-axis motor 21 appropriate. The rotation information detector 28 , which detects information such as an angle, an angular velocity, and an angular acceleration of the rotor with respect to the stator, is on the Y-axis motor 22 appropriate. In the first embodiment, the rotation information detectors 27 and 28 described as optical encoders that detect the angle of the rotor with respect to the stator.

[0034] In the first embodiment, the X-axis drive mechanism 23 and the Y-axis drive mechanism 24 made up of shafts coupled to the rotors of the X-axis motor and the Y-axis motor via couplings, driving pulleys connected to the shafts, and drive belts interconnecting the driving pulleys and driven pulleys. The X-axis drive mechanism 23 and the Y-axis drive mechanism 24 however, are not limited to this. It is obvious that ball screw mechanisms or ball spline mechanisms can also be used. The X-axis motor 21 and the Y axis motor 22 need not necessarily be a rotating electric machine such as a servo motor or a stepping motor. From a technical standpoint that ignores cost, it can be the X-axis motor 21 and the Y-axis motor 22 be a variety of actuators such as linear motors, planar motors or spherical motors.

[0035] The running sled 25 is with the holding device 26 is coupled, which holds the sewn object and transports the sewn object in the X-axis and Y-axis directions. The running sled 25 is driven by the X-axis motor 21 and the Y-axis motor 22 driven so that the sewn object is positioned at a predetermined position with respect to the sewing needle. In the first embodiment, the holding device 26 constructed from a feed plate 29 , which is a feed plate; an outside pusher 210 ; a press table 211 ; and an air cylinder 212 . The Holding Device 26 however, is not limited to this. It is sufficient if the holding device 26 is a device represented, for example, by a robot hand holding the sewn object on top of the slide plate 4 can hold and transport.

[0036] The feed plate 29 the holding device 26 who use the trolley 25 coupled is at the top of the in figure 1 slide plate shown 4 arranged. If the holding device 26 positioned in the horizontal direction becomes the feed plate 29 smoothly at the top of the skid plate 4 guided. For this reason, it is desirable to choose the materials for the sliding plate 4 and the feed plate 29 select such that the coefficient of friction between the sliding plate 4 and the feed plate 29 is reduced.

[0037] The running sled 25 is with the pusher table 211connected to the trolley 25 and the outer pusher 210 rigidly coupled.

[0038] The sewn item is between the feed plate 29 and the outer pusher 210 arranged, with the outer handle 210 vertically from top to bottom on the feed plate 29 presses, causing the holding device 26 holding the sewn item. At this time, in order to maintain the holding force, in the first embodiment, a pneumatic press is used to adjust the pressure with the air cylinder 212 used. However, this is not a limitation. Other methods such as an electromagnetic press or a hydraulic press can also be used.

[0039] A control structure of the sewing machine 100 according to the first embodiment, reference is made to FIG figure 5 explained. figure 5 is a block diagram showing the control structure of the sewing machine according to the first embodiment. Before the control structure of the sewing machine 100 is explained, the operation of the sewing machine 100 explained in an overview. At the sewing machine 100 will when the footswitch 33 is pressed, a hold signal output of the footswitch 33 to the control panel 32A sent. The air cylinder 212 is operated according to this stop command signal. The sewn item is fed between the feed plate 29 and the inside figure 4 shown outer pusher 210 held. Subsequently, when the foot switch 33 is pressed and an operation start signal output from the foot switch 33 to the control panel 32A is sent, the spindle motor 14 , which is a drive source of the sewing mechanism P1 and the feeding mechanism P2 acts, the engine 16 of the central pusher, the X-axis motor 21 and the Y axis motor 22 operated. The sewing machine 100 begins at a position set by the user of the sewing machine 100 using the control panel 31 has been predetermined to form a seam in the sewn object. Circuit layout of the control panel 31

[0040] As in figure 5 is the control panel 31 the sewing machine 100 built from an ad 311 ; a processor 312 ; a storage device 313 , which is the sewing pattern data D1 and the sewing print data D2 stores; and an input device 314 . The user of the sewing machine 100 activates the input device 314 , which are designed as push buttons or a touch pad, referring to the display 311 obtains, and outputs the sewing pattern data D1 for each stitch and the sewing print data D2 generated according to the repulsive force of the sewn object. This data is stored in the storage device 313 the control panel 31 saved. An operating system of the operator panel 31 is through the processor 312 operated.

[0041] The ones through the control panel 31 generated sewing pattern data D1 and sewing print data D2 are through the processor 312 as a sewing command signal to the control panel 32A transfer. In the sewing pattern data D1 is data for determining the drive patterns of the spindle motor 14 , of the motor 16 the center pusher, the X-axis motor 21 and the Y-axis motor 22 . At the sewing print data D2 is data for determining a driving pattern at the time when the motor 16 of the center presser exerts a downward pressing force on the sewn object. It should be noted that the sewing print data D2 be adjusted so that the pressing accuracy of the central pusher 15 is mainly improved when a sewn article is stretchable. In this way, the sewing print data D2 is set when the repulsive force of the sewn object can be input in advance using a mathematical model or a measuring device. The sewing print data D2do not necessarily need to be adjusted if the sewn item is inextensible or if the repulsion force is unknown. The storage device 313 is not on one in the control panel 31 provided memory device limited. The storage device 313 can be a storage device located outside the control panel 31 and is connected by a communication device, whether the communication device is wired or wireless. Using the memory device makes it easy to create, edit and copy a sewing pattern. [Circuit Structure of Control Panel 32A]

[0042] As in figure 5 includes the control panel, 32A, which controls the sewing machine 100 controls, at least one command generating device 321 , an arithmetic circuit 322 to control the spindle motor, an arithmetic circuit 323 to regulate the motor of the central pusher, an arithmetic circuit 324 for controlling the X-axis motor and an arithmetic circuit 325 to control the Y-axis motor. In addition, includes the control panel 32A in some cases, a control circuit that drives a solenoid that cuts the thread when sewing is complete; a notification sensor to notify the user that a thread has run out and a position sensor used to return the feeding mechanism to the starting point; and a power supply circuit. Since these circuits are not directly related to the effects of the present invention, an explanation of these circuits is omitted.

[0043] The Control Panel 32A receives the inputs of a sewing command signal generated by the processor 312 the control panel 31 is issued; a stop signal and an operation start signal by the foot switch 33 be issued; a spindle rotation signal detected by the rotation information detector 18 of the spindle motor 14 is issued; a center pusher rotation signal detected by the rotation information detector 124 of the motor 16 of the central pusher; an X-axis rotation signal detected by the rotation information detector 27 of the X-axis motor 21 is issued; and a Y-axis rotation signal detected by the rotation information detector 28 of the Y-axis motor 22 is issued. The Control Panel 32A outputs a spindle drive signal for driving the spindle motor based on these signals 14 ; a signal to operate the central pusher to drive the motor 16 the central pusher; an X-axis drive signal for driving the X-axis motor 21 ; a Y-axis drive signal for driving the Y-axis motor 22 ; and a stop command signal for driving the air cylinder 212 the end.

[0044] The command generator 321 receives inputs of the sew command signal processed by the processor 312 the control panel 31 is output, as well as the stop signal and the operation start signal which are output by the foot switch 33 are output, and then outputs a spindle command signal, a center pusher command signal, an X-axis command signal, a Y-axis command signal, and a stop command signal. The spindle command signal, the center pusher command signal, the X-axis command signal, and the Y-axis command signal are electric signals for determining the rotation angles of the spindle motor, respectively 14 , of the motor 16 the center pusher, the X-axis motor 21 and the Y-axis motor 22 , where they are generated by the command generator 321 in accordance with the sewing pattern data D1 be calculated. The stop command signal is an electric signal for determining the pressure of the air cylinder so that the sewn object is between the feed plate 29 and the outer pusher 210 is held. The operation start command signal is an electric signal for determining the timing at which the command generating device 321starts, the spindle command signal, the center pusher command signal, the X-axis command signal and the Y-axis command signal to the arithmetic circuit, respectively 322 for controlling the spindle motor, the arithmetic circuit 323 for controlling the motor of the central pusher, the arithmetic circuit 324 to control the X-axis motor and the arithmetic circuit 325 to control the Y-axis motor.

[0045] The arithmetic circuit 322 for controlling the spindle motor receives inputs of the spindle command signal and the spindle rotation signal and then outputs a spindle operation signal for rotating the spindle motor 14 off so that the difference between the spindle command signal and the spindle rotation signal becomes 0. In this way, the arithmetic circuit includes 322 for controlling the spindle motor, at least one of a proportional compensator that performs a proportional operation, an integral compensator that performs an integral operation, and a differential compensator that performs a differential operation. In the first embodiment, it is described that a PI control performed by the proportional compensator and the integral compensator is included in the arithmetic circuit 322 used to control the spindle motor.

[0046] The arithmetic circuit 323 for controlling the center pusher motor receives inputs of the center pusher command signal and the center pusher rotation signal and then rotates the motor 16 of the center handle so that the difference between the center handle command signal and the center handle rotation signal 0 will. In this way, the arithmetic circuit includes 323 for controlling the center pusher motor, at least one of a proportional compensator that performs a proportional operation, an integral compensator that performs an integral operation, and a differential compensator that performs a differential operation. In the first embodiment, it is described that a PI control performed by the proportional compensator and the integral compensator is included in the arithmetic circuit 323 used to regulate the motor of the central pusher.

[0047] The arithmetic circuit 324 for controlling the X-axis motor receives inputs of the X-axis command signal and the X-axis rotation signal and then outputs an X-axis operation signal for rotating the X-axis motor 21 out so that the difference between the X-axis command signal and the X-axis rotation signal 0 will. In this way, the arithmetic circuit includes 324 for controlling the X-axis motor, at least one of a proportional compensator that performs a proportional operation, an integral compensator that performs an integral operation, and a differential compensator that performs a differential operation. In the first embodiment, it is described that a PI control performed by the proportional compensator and the integral compensator is included in the arithmetic circuit 324 used to control the X-axis motor.

[0048] The arithmetic circuit 325 for controlling the Y-axis motor receives inputs of the Y-axis command signal and the Y-axis rotation signal, and then outputs a Y-axis operation signal for rotating the Y-axis motor so that the difference between the Y- axis command signal and the Y-axis rotation signal 0 will. In this way, the arithmetic circuit includes 325 for controlling the Y-axis motor, at least one of a proportional compensator that performs a proportional operation, an integral compensator that performs an integral operation, and a differential compensator that performs a differential operation. In the first embodiment, it is described that a PI control performed by the proportional compensator and the integral compensator is included in the arithmetic circuit 325 used to control the Y-axis motor.

[0049] The times when the sewing needle 11 , the boat 12 , the central pusher 15 , the thread lever 13, the X-axis motor 21 and the Y axis motor 22 are operated with reference to figure 6 and figure 7 explained.

[0050] figure 6 is a time chart when the sewing machine according to the first embodiment is operated with a conventional drive pattern. figure 7 is a time chart when the sewing machine according to the first embodiment is operated with a driving pattern according to the present invention.

[0051] figure 6 shows the position of the sewing needle from top to bottom 11 in relation to the angle of rotation of the spindle motor 14 ; the angle of rotation of the boat 12 in relation to the angle of rotation of the spindle motor 14 ; the position of the central pusher 15 in relation to the angle of rotation of the spindle motor 14 ; the position of the take-up lever 13 in relation to the angle of rotation of the spindle motor 14 ; the position of the X-axis motor 21 in relation to the angle of rotation of the spindle motor 14 ; and the position of the Y-axis motor 22 in relation to the angle of rotation of the spindle motor 14 .

[0052] As in figure 6 are the times at which the sewing needle 11 , the boat 12 , the central pusher 15 , the thread lever 13 , the X-axis motor 21 and the Y axis motor 22 the sewing machine 100 be operated according to the rotation angle of the spindle motor 14 synchronized with each other. The following description uses the sewing needle 11 , the boat 12 , the central pusher 15 , the thread lever 13 , the X-axis motor 21 and the Y axis motor 22 the sewing machine 100 , by the control device P3 are driven are collectively described as objects to be driven.

[0053] Waveforms at the time when the objects to be driven are controlled by the conventional driving pattern are in figure 6 shown. Waveforms at the time the objects to be driven are controlled by the drive pattern according to the first embodiment are shown in FIG figure 7 shown. The waveforms are driving waveforms of objects to be driven for the (n-1)th stitch and subsequent stitches at the time when sewing for n or more stitches (n≥3) is repeatedly performed. Driving patterns of objects to be driven are shown, with a seam in a first sewn object Ob1 formed with the (n-1)th stitch and sewn items Ob1 and Ob2 sewn together with the nth stitch and subsequent stitches. [Drive with the conventional drive pattern]

[0054] To explain the features of the present invention, the objects of the sewing machine to be driven will first be explained 100 explained, which are driven with the conventional drive pattern. In the following description, a case where, as in the patent literature 2 revealed, the central pusher 15 presses down on the sewn object when a needle moves up from the bottom dead center and the tip of the shuttle 12 picks up the needle thread.

[0055] In the conventional drive pattern, the following is particularly observed: After the holding device 26 of the feeding mechanism P2 sewn object has stopped at a predetermined position and has finished feeding, presses the center pusher 15 down on the sewn item when the sewing needle 11 and the boat 12 cooperate and the needle thread and the bobbin thread are crossed. In this case, the waveform draws the position of the center pusher 15 for the (n-1)th stitch, a sine wave with respect to the angle of rotation of the spindle motor 14 after.

[0056] As in the upper section of figure 6 shows the waveform of the position of the sewing needle 11 , by the spindle motor 14is driven is controlled by the spindle operation signal so that it is at the top dead center when the rotation angle of the spindle motor 14 a=0° (=360°) before sewing of the (n-1)th stitch is started. The sewing needle 11 starts to move in unison with the rotation of the spindle motor 14 to lower from top dead center; she becomes into the sewn object Ob1 introduced when the rotation angle of the spindle motor 14 are you; and it reaches the bottom dead center when the angle of rotation is c=180°. The tip of the boat 12 at a time when the angle of rotation is d, grasps a ring formed by the needle thread passing through the eye of the sewing needle 11 is inserted, whereby the needle thread and the bobbin thread are entangled.

[0057] In figure 6 will be the position of the sewing needle 11 at the time when the rotation angle of the spindle motor 14 d is indicated by a black circle. In the following description, this point in time will be referred to as the meeting of the sewing needle 11 and the boat 12 described. The sewing needle 11 becomes from the sewn object Ob1 pulled out when the rotation angle of the spindle motor 14 e is. Then the sewing needle rises 11 further on. When the rotation angle of the spindle motor 14 a' reaches the sewing needle 11 the top dead center at which the sewing needle 11 starts sewing the nth stitch.

[0058] At the nth stitch and the following stitches, the sewing needle sews 11 the sewn items Ob1 and Ob2 together. At the nth stitch, the sewing needle 11 regulated in such a way that they are at the angle of rotation a'=0° of the spindle motor 14 is at top dead center, that it is inserted at b', that it is at bottom dead center at c'=180°, that it hits the shuttle at d', that it is extracted at e' and that it moves at (n +1)-th stitch is at a"=360° at top dead center.

[0059] The waveform of the position of the sewing needle 11 however, is adjusted to produce a sine wave of amplitude at the (n-1)th stitch 1h is. If the sewn item Ob2 is particularly thick, the period of the nth stitch from a' to b' is shorter than the period of the (n-1)th stitch from a to b, and the period of the nth stitch from d' to e' is longer than the period of the (n-1)th stitch from d to e. Consequently, the sewing needle 11 driven such that the needle insertion time th' of the nth stitch from b' to e' is longer than the needle insertion time th of the (n-1)th stitch from b to e.

[0060] The second section from the top in figure 6 shows the rotation angle of the boat 12 , which corresponds to the angle of rotation of the spindle motor 14 is equivalent to. The angle of rotation is a sine wave with the amplitude 1k . When a full rotation boat is used, the frequency of the waveform is the rotation angle of the boat 12 twice the frequency of the waveform of the sewing needle position 11 . The black circles in the second part of figure 6 indicate the times at which the needle hits the shuttle. When the rotation angle of the spindle motor 14 d or d', grabs the tip of the shuttle 12 a loop formed by the needle thread. Releasing the by the shuttle 12 gripped needle thread begins at the angle of rotation i of the spindle motor 14 , where the boat 12 one and a half revolutions starting from the angle of rotation a of the spindle motor 14 has executed. The boat 12 performs the same operation for the (n-1)th stitch and the nth stitch.

[0061] The third section from the top in figure 6 shows a waveform of the position at the time when the center pusher 15 is operated with the conventional drive pattern, i.e. with a drive pattern which has a sinusoidal path in relation to the angle of rotation of the spindle motor 14 having. As indicated in the figure by a white circle, the central pusher reaches 15in this case, the bottom dead center at the time when the needle hits the shuttle, i.e. when the angle of rotation of the spindle motor 14 d is The middle pusher 15 presses the sewn item Ob1 for a period dto against the top of the skid plate 4 , which is shorter than the period when using the driving pattern of the present invention, which will be explained later. If the movement trace of the central pusher 15 is adjusted in such a way that the amplitude is lo at the (n-1)th stitch, the central pusher 15 the thickness of the sewn item Ob2 however, do not cope when the sewn items Ob1 and Ob2 sewn together with the nth stitch. Contrary to the intention of the user of the sewing machine 100 , which is the sewing pattern data D1 has entered, the middle pusher presses 15 in this way for a period of time to' on the sewn objects Ob1 and Ob2 down, during which the angle of rotation of the spindle motor 14 changed from f to g. In this case, the central pusher lowers 15 to lo 'down from top dead center, where he is with the sewn object Ob2 collided and stopped. In this way, the central pusher 15 the surface of the sewn item Ob2 to damage. In order to avoid the collision, it suffices if the drive pattern is changed to a sinusoidal drive pattern with the amplitude lo' at the nth stitch. When the amplitude is changed, however, the period of time to' during which the central pusher 15 pressed down on the sewn object is shorter than when the amplitude is not changed.

[0062] The fourth section from the top in figure 6 shows a movement trace of the pinhole 122 the thread lever 13 according to the angle of rotation of the spindle motor 14 . The little hole 122 the thread lever 13 performs the same operation on the (n-1)th stitch and on the nth stitch. Specifically, corresponds to a pinhole cycle 122 one rotation of the spindle motor 14 . The little hole 122 reaches the top dead center at a timing of the rotation angle h (=h') of the spindle motor 14 , and it reaches the bottom dead center at a timing of the rotation angle i (=i').

[0063] By mechanically adjusting the center of rotation of the oscillation of the take-up lever 13 and the thread take-up rod 123 becomes the angle of rotation h of the spindle motor 14 , at which the small hole 122 the thread lever 13 reaches top dead center, to an angle between the start of rotation of the spindle motor 14 and inserting the sewing needle 11 into the sewn object Ob1 or Ob2 set, i.e. to an angle between the angle of rotation a and the angle of rotation b of the spindle motor 14 or an angle between the rotation angle a' and the rotation angle b' of the spindle motor 14 . In the first embodiment, an angle which is 60° from the rotation angle a or a' of the spindle motor 14 was rotated is set as the rotation angle h or h' at which the small hole 122 the thread lever 13 reaches top dead center.

[0064] Furthermore, the rotation angle i of the spindle motor 14 , at which the small hole 122 reaches the bottom dead center, adjusted to the timing at which the rotation angle of the shuttle 12 made one and a half turns from a or a'. The reason for this is that the release of the shuttle 12 gripped needle thread at angle of rotation i of the spindle motor 14 begins. If the small hole 122 the thread lever 13 is raised before passing through the shuttle 12 When the needle thread is released, the needle thread cannot withstand the tension generated when the thread take-up lever rises 13 applied, causing the needle thread to fray or break. Specifically, the take-up lever reaches 13 in the first embodiment, the bottom dead center when the rotation angle i of the spindle motor 14 is 270°.

[0065] In order to avoid such a phenomenon, the top dead center and the bottom dead center of the thread take-up lever 13 set as explained above. At the (n-1)th stitch, there is a relationship td>tu between a rotating angle td of the spindle motor 14 during a period in which the in the take-up lever 13 intended small hole 122 from top dead center to bottom dead center, and a rotation angle tu of the spindle motor 14 during a period during which the small hole 122 increases from bottom dead center to top dead center. Similarly, at the n-th stitch, there is a relationship td'>tu' between a rotation angle td' of the spindle motor 14 during a period in which the small hole 122 from top dead center to bottom dead center drops, and a rotation angle tu 'of the spindle motor 14 during a period in which the small hole 122 increases from bottom dead center to top dead center.

[0066] The fifth section from the top in figure 6 shows a waveform of the position of the X-axis motor 21 powered holding device 26 in the X-axis direction. A mark lx in the figure shows the moving distance of the holding device 26 which moves in the X-axis direction stitch by stitch. The Holding Device 26 is driven in such a way that it stands still while the sewing needle 11 into the sewn object Ob1 is inserted, and that it will move after the suture needle is withdrawn 11 from the sewn object Ob1 moved up the sewing needle 11 back into the sewn object Ob2 is introduced.

[0067] Specifically, the period during which the rotation angle of the spindle motor 14 changes from b to b' as one cycle is set, with the X-axis motor changing 21 during a period of time tm up to the rotation angle b of the spindle motor 14 turns to which the sewing needle 11 at the (n-1)th stitch in the sewn object Ob1 is introduced. The X-axis motor 21 stands for a period of time ts from the angle of rotation b of the spindle motor 14 up to the angle of rotation e of the spindle motor 14 still, at which the sewing needle 11 from the sewn object Ob1 is pulled out. Then, to perform the sewing of the nth stitch, the X-axis motor rotates 21 during a period tm' from the rotation angle e of the spindle motor 14 , in which the sewing needle 11 is pulled out at the (n-1)th stitch, to the angle of rotation b', at which the sewing needle 11 at the nth stitch into the sewn object Ob2 is introduced. Then the X-axis motor stops 21 during a period ts' silent until the sewing needle 11 at the nth stitch from the sewn item Ob2 is pulled out.

[0068] The sixth section from the top in figure 6 shows a waveform of the position of the Y-axis motor 22 powered holding device 26 in Y-axis direction. A mark ly in the figure indicates the moving distance of the holding device 26 which moves in the Y-axis direction stitch by stitch. As with the drive pattern in the X-axis direction, the jig 26 driven in such a way that it stands still while the sewing needle 11 into the sewn object Ob1 is inserted, and that it will move after the suture needle is withdrawn 11 from the sewn object Ob1 moved up the sewing needle 11 back into the sewn object Ob2 is introduced.

[0069] Specifically, the period during which the rotation angle of the spindle motor 14 changes from b to b' as one cycle, with the Y-axis motor changing 22 rotates during the period tm up to the angle of rotation b at which the sewing needle 11 at the (n-1)th stitch in the sewn object Ob1 is introduced. The Y axis motor 22 stands still during the period ts from the angle of rotation b to the angle of rotation e, at which the sewing needle 11 from the sewn object Ob1is pulled out. To perform the sewing of the nth stitch, the Y-axis motor rotates 22 then during the period tm' from the rotation angle e of the spindle motor 14 , in which the sewing needle 11 is pulled out at the (n-1)th stitch, to the angle of rotation b', at which the sewing needle 11 at the nth stitch into the sewn object Ob2 is introduced. Then the Y-axis motor stops 22 during the period ts' silent until the sewing needle 11 at the nth stitch from the sewn item Ob2 is pulled out.

[0070] In the example where the driven body of the sewing machine 100 are driven with the conventional drive pattern, the center pusher is driven in this manner to follow a sinusoidal trajectory with respect to the angle of rotation of the spindle motor 14 follows, so that the central pusher 15 at the time when the needle is on the shuttle 12 hits, presses down on the sewn object. In this way, it is possible to reduce the rate of occurrence of stitch skipping, which is a phenomenon in which the needle thread and the bobbin thread are not entangled and thus a seam is not formed. Because the engine 16 of the central pusher is not driven in such a way that the central pusher 15 presses down on the sewn object while the thread take-up lever is engaged 13 intended small hole 122 increases, but that fluctuates due to the take-up lever 13 tensile force provided on the needle thread with each stitch, whereby the seam tightness of a seam is insufficient in some cases. Thereby, in the present invention, the method of driving the motor 16 of the central pusher changed as explained below. [Drive with the drive pattern of the present invention]

[0071] In figure 7 there is a trace of movement of the central pusher shown in the third section 15 , a waveform shown in the fifth section of the position of the X-axis motor 21 powered holding device 26 in the X-axis direction and a waveform shown in the sixth section of the position of the Y-axis motor 22 powered holding device 26 in the Y-axis direction from those in figure 6 shown. The waveforms of the sewing needle position 11 and the thread lever 13 , by the spindle motor 14 are driven are the same as they are in figure 6 are shown. On a description of parts that are the same as those in figure 6 are parts shown are omitted.

[0072] A waveform of the position of the sewing needle shown in the top section 11 and one in the second section of figure 7 waveform of the rotation angle of the boat 12 are the same as they are in figure 6 are shown. Black dots indicate the times when the needle hits the shuttle.

[0073] Now there is a trace of movement of the central pusher 15 explained in the third section of figure 7 is shown. After starting to descend from the top dead center or from the stop position in accordance with the rotation of the engine 16 of the center pusher becomes the center pusher 15 at the (n-1)th stitch so that it is driven during a period of time before the sewing needle 11 is inserted into the sewn object, in contact with the top of the sewn object Ob1 arrives after the transport of the holding device 26 by the rotation of the X-axis motor 21 and the Y-axis motor 22 is completed. Because the sewn item Ob1 is not stretchable, the central pusher presses 15 on the sewn object Ob1 in height down to which the central pusher 15 drops to come into contact with the sewn item Ob1 to get. The middle pusher 15 presses on the sewn item Ob1 down before the sewing needle 11 into the sewn object Ob1 is introduced. The middle pusher15 then climbs off the sewn item Ob1 on after the take-up lever 13 has reached top dead center. The extent of sinking and the extent of rising of the central pusher 15 at this time are 1o. The middle pusher 15 pushes at least during a period between the rotation angles b and h' of the spindle motor 14 on the sewn object Ob1 down. In this way, at the (n-1)th stitch, the center presser driven by the drive pattern according to the first embodiment presses 15 at the time of inserting the sewing needle 11 ; at the bottom dead center of the sewing needle 11 ; at the time when the sewing needle 11 on the boat 12 meets, at the time of withdrawal of the sewing needle 11 ; and while the thread lever 13 increases from the bottom dead center to the top dead center on the sewn object Ob1 down. The middle pusher 15 is held at a fixed height in the position to which the central pusher 15 drops to come into contact with the sewn item Ob1 to get. The height at this point is the height obtained by dividing the thickness of the sewn item Ob1 to the top of the feed plate 29 is added to the sewn item Ob1 located. With the nth stitch, as with the (n-1)th stitch, the central presser is reached 15 after the start of the descent from the top dead center in accordance with the rotation of the engine 16 of the center presser during a period before the sewing needle 11 into the sewn object Ob2 is introduced, and after the transport of the holding device 26 is completed, in contact with the sewn object Ob2 . After coming into contact with the sewn item Ob2 reached, the central pusher arrives 15 in contact with the sewn item Ob2 , before the sewing needle 11 into the sewn object Ob2 is inserted and rises from the sewn object Ob2 on after the take-up lever 13 in accordance with the regulation of the rotation angle of the motor 16 of the central pusher has reached top dead center. Because the sewn items Ob1 and Ob2 are not stretchable, presses the central pusher 15 on the sewn items Ob1 and Ob2 in height down to which the central pusher 15 drops to come into contact with the sewn item Ob2 to get. The middle pusher 15 presses on the sewn items Ob1 and Ob2 down before the sewing needle 11 into the sewn object Ob2 is introduced. The middle pusher 15 rises from the sewn item Ob2 on after the take-up lever 13 has reached top dead center.

[0074] The extent of sinking and the extent of rising of the central pusher 15 at this time are lo'. The middle pusher 15 presses between the angles of rotation b' and h" of the spindle motor for at least a period of time to' 14 on the sewn object Ob2 down. In this way, the amount of lowering of the central presser changes at the nth stitch compared to the (n-1)th stitch 15 from lo to lo', and the pressing period changes from to to to'.

[0075] At the extent of sinking lo and lo' of the central pusher 15 are parameters that change in accordance with the thickness of the sewn object. The sinking amounts lo and lo' must be preset as sewing pattern data D1 be entered. If the height of the top dead center of the center pusher 15 in relation to the sliding plate 4 is fixed, lo and lo' can be calculated by inputting the thickness of the sewn object. In addition, the pressing periods to and to' also change in accordance with the thickness of the sewn object. However, since the angles of rotation b, b', h' and h" of the spindle motor 14can be calculated using a sine wave function in accordance with the thickness of the sewn object, the pressing periods to and to' need not be input in advance.

[0076] In this way, the middle presser also presses with the nth stitch 15 , which is driven with the drive pattern according to the first embodiment, at the time of inserting the sewing needle 11 ; at the bottom dead center of the sewing needle 11 ; at the time when the sewing needle 11 on the boat 12 meets; at the time of pulling out the sewing needle 11 ; and while the thread lever 13 increases from the bottom dead center to the top dead center on the sewn object Ob1 down. The middle pusher 15 is held at a fixed height in the position to which the central pusher 15 drops to come into contact with the sewn item Ob2 to get. The height at this point is the height that is obtained by dividing the thickness of the sewn items Ob1 and Ob2 to the top of the feed plate 29 is added to the sewn items Ob1 and Ob2 condition.

[0077] The fourth section from the top in figure 7 shows a trace of movement of the take-up lever 13 , which corresponds to the rotation angle of the spindle motor 14 is equivalent to. The motion track is the same as the motion track in figure 6. Therefore, a description thereof is omitted.

[0078] The fifth section from the top in figure 7 shows a waveform of the position of the X-axis motor 21 powered holding device 26 in the X-axis direction. A mark lx in the figure indicates the moving distance of the holding device 26 which moves in the X-axis direction stitch by stitch. The Holding Device 26 is driven in such a way that it stands still while the sewing needle 11 into the sewn object Ob1 is inserted and while the central pusher 15 on the sewn object Ob1 or Ob2 down. This is how the X-axis motor positions 21 the holding device 26 , while the spindle motor 14 turns from h to b and while turning from h' to b'.

[0079] The sixth section from the top in figure 7 shows a waveform of the position of the Y-axis motor 22 powered holding device 26 in the Y-axis direction. In a similar way to the X-axis motor, the Y-axis motor positions 22 the holding device 26 , while the spindle motor 14 turns from h to b and while turning from h' to b'. [Effects of the first embodiment]

[0080] In this way, the central pusher 15 the sewing machine 100 according to the first embodiment at the time of inserting the suture needle 11 ; at the bottom dead center of the sewing needle 11 ; at the time when the sewing needle 11 on the boat 12 meets; at the time of pulling out the sewing needle 11 ; and while the thread lever 13 increases from the bottom dead center to the top dead center on the sewn objects Ob1 and Ob2 press down This can at the sewing machine 100 according to the first embodiment, a needle deflection can be prevented in which the sewing needle 11 at the time of insertion and at the time of withdrawal of the suture needle 11 vibrates in the horizontal direction with respect to the sewn item, and it becomes a by the friction between the sewn items Ob1 and Ob2 and the sewing needle 11 caused flapping and floating of the sewn items Ob1 and Ob2 prevented while the sewing needle 11 increases, and the accuracy of the seam tightening of a seam by the thread take-up lever 13 be improved.

[0081] In addition, at the sewing machine 100 according to the first embodiment, the motor 16 of the central pusher independent of the spindle motor 14 powered by the sewing needle 11drives. I.e. the central pusher 15 can be independent of the operation of the sewing needle 11 are driven. In this way is a mechanism for connecting the spindle motor 14 and the central pusher 15 unnecessary. Therefore, the user of the sewing machine 100 the extent of sinking and the extent of rising of the central pusher 15 change and the pressing period of the central pusher 15 change by a position command of the motor 16 of the central pusher can be changed without adjusting the mechanical system. It should be noted that in the first embodiment, the spindle motor 14 as a drive source for the sewing needle 11 , the boat 12 and the thread lever 13 is used. The sewing needle 11 , the boat 12 and the thread lever 13 however, they can also be driven by drive sources that are provided independently of each other.

[0082] In addition, the command generating device of the sewing machine generates 100 According to the first embodiment, a drive signal for the drive source that presses the center presser in a period until the small hole has risen in accordance with the operation of the thread take-up lever to reach the top dead point after releasing the needle thread caught by the shuttle, in a fixed height with respect to the surface of the sewn object. Thereby, the drive source drives the center presser to be in the fixed position in the period until the small hole rises in accordance with the operation of the thread take-up lever to reach the top dead center after releasing the needle thread caught by the shuttle height in relation to the surface of the sewn object stops. In this way, compared to the case where the drive source drives the center presser to stop at a fixed height with respect to the top of the stand on which the sewn article is placed, it is possible to reduce the possibility of damage to the to reduce the surface area of ​​the sewn object and to prevent the sewn object from floating and fluttering. Second embodiment.

[0083] figure 8 is a timing chart showing a driving pattern of a sewing machine according to a second embodiment. The sewing machine 100 according to the second embodiment differs from the sewing machine 100 according to the first embodiment in that they have different timing charts for driving the center pusher 15 , the X-axis motor 21 and the Y-axis motor 22 the sewing machine 100 having. The other drive patterns and the construction of the sewing machine 100 according to the second embodiment are the same as the sewing machine 100 according to the first embodiment. Therefore, description of similar portions is omitted.

[0084] One in the upper section of figure 8 waveform of the position of the sewing needle 11 and a waveform of the rotation angle of the boat shown in the second section 12 are the same as they are in figure 7 are shown. Black circles in the figure indicate the times when the sewing needle 11 on the boat 12 meets.

[0085] Now, one in the third section of figure 8 shown movement trace of the central pusher 15 explained. With the (n-1)th stitch, the middle presser is reached 15 after the start of the descent from the top dead center in accordance with the rotation of the engine 16 of the center presser during a period before the sewing needle 11 into the sewn object Ob1 is introduced and after the transport of the holding device 26 by the rotation of the X-axis motor 21 and the Y-axis motor 22 is completed, in contact with the sewn object Ob1 . Because the sewn item Ob1 is not stretchable, the central pusher presses 15 in height, on which the central pusher 15 drops to come into contact with the sewn item Ob1 to get to the sewn object Ob1 down. The middle pusher 15 presses on the sewn item Ob1 down before the sewing needle 11 into the sewn object Ob1 is introduced. The middle pusher 15 rises from the sewn item Ob1 on after the sewing needle 11 from the sewn object Ob1 was pulled out. The amount of drop in the center pusher 15 at this time is lo. The extent of the rise of the central pusher 15 at this time is dlo. The amount of rise dlo is an amount that provides an air gap to prevent the needle thread from getting between the center presser 15 and the sewn item Ob1 gets stuck when the fixture is stalled by the rotation of the X-axis motor 21 and the Y-axis motor 22 is transported after passing through the eye of the sewing needle 11 inserted needle thread to the top of the sewn object Ob1 was raised.

[0086] After he order dlo from the sewn item Ob1 has risen, the central pusher retains it 15 at a fixed height, up to the angle of rotation of the spindle motor 14 h' reached at which the take-up lever 13 reaches top dead center on the nth stitch. I.e. while the thread lever 13 moved from the bottom dead center towards the top dead center, the central pusher keeps 15 the fixed height at a height at which the central pusher 15 starting from the position in which the central pusher 15 on the sewn object Ob1 down to dlo has increased. Then the central pusher rises 15 starting from the position to which the central pusher 15 increased by dlo, further increased by a distance equal to or greater than the thickness of the sewn article Ob2 is to avoid collision with the sewn item Ob2 to avoid. Then the central pusher 15 shifted to operation for the nth stitch.

[0087] With the nth stitch, the middle presser 15 after the start of the descent from the top dead center in accordance with the rotation of the engine 16 of the central pusher so driven that he during a period before the sewing needle 11 into the sewn object Ob2 is introduced after the rotation of the X-axis motor 21 and the Y-axis motor 22 stops and the transport of the holding device 26 is completed, in contact with the sewn object Ob2 reached.

[0088] Because the sewn items Ob1 and Ob2 are not stretchable, presses the central pusher 15 in the height to which the central pusher 15 drops to come into contact with the sewn item Ob2 to get to the sewn items Ob1 and Ob2 down. The middle pusher 15 presses on the sewn item Ob2 down before the sewing needle 11 into the sewn object Ob2 is introduced. The middle pusher 15 then climbs off the sewn item Ob2 on after the sewing needle 11 from the sewn object Ob2 was pulled out. The amount of drop in the center pusher 15 at this time is lo'. The amount of increase dlo is the same as the amount of increase at the (n-1)th stitch. After starting from the position in which the central pusher 15 on the sewn object Ob2 presses down has risen by ldo, the center pusher becomes 15 is maintained at a fixed height until the rotation angle of the spindle motor reaches a rotation angle h' of the spindle motor at which the thread take-up lever 13 reaches top dead center on the nth stitch. I.e. while the thread lever 13 moved from bottom dead center towards top dead center, the center pusher 15 held at a fixed height at the position to which the central pusher 15 starting from the position in which the central pusher 15 on the sewn object Ob2down to dlo has increased. Then the central pusher 15 shifted to operation for the (n+1)th stitch. If the sewn items Ob1 and Ob2 , which have the same thicknesses as the thicknesses at the nth stitch are sewn together by the (n+1)th stitch, it is possible that the center presser 15 unlike the (n-1)th stitch, starting from the position to which the central presser 15 has increased by dlo, does not continue to increase.

[0089] As described above, the central pusher presses 15 at least during a period ta between the angles of rotation b and e of the spindle motor 14 and a period ta' between the rotation angles b' and e' of the spindle motor 14 on the sewn items Ob1 and Ob2 down. This is how the central pusher presses 15 at the time of inserting the sewing needle 11 , at the bottom dead center of the sewing needle 11 , at the time when the sewing needle 11 on the boat 12 hits, and at the time of pulling out the sewing needle 11 on the sewn objects Ob1 and Ob2 down. While the thread lever 13 increases from bottom dead center to top dead center, the center pusher 15 held at a fixed height at the position to which the central pusher 15 um dlo starting from the sewn item Ob1 or Ob2 has increased.

[0090] The fourth section from the top in figure 8 shows a trace of movement of the take-up lever 13 , which corresponds to the rotation angle of the spindle motor 14 is equivalent to. This trace of movement is the same as that shown in figure 7 is shown. Therefore, a description thereof is omitted.

[0091] The fifth section from the top in figure 8 shows a waveform of the position of the X-axis motor 21 powered holding device 26 in the X-axis direction. A mark lx in the figure indicates the moving distance of the holding device 26 which moves in the X-axis direction stitch by stitch. In the second embodiment, the holding device 26 as in the fifth section of figure 6 driven in such a way that it stands still while the sewing needle 11 into the sewn object Ob1 or Ob2 is introduced.

[0092] The sixth section from the top in figure 8 shows a waveform of the position of the Y-axis motor 22 powered holding device 26 in the Y-axis direction. A mark ly in the figure indicates the moving distance of the holding device 26 which moves in the X-axis direction stitch by stitch. In the second embodiment, the holding device 26 as in the sixth section of figure 6 driven in such a way that it stands still while the sewing needle 11 into the sewn object Ob1 or Ob2 is introduced. [Effects of the second embodiment]

[0093] In the sewing machine according to the second embodiment, the lifting is performed such that during a period between the rotation angles e and h' of the spindle motor 14 at the (n-1)th stitch and during a period between the rotation angles e' and h'' of the spindle motor 14 at the nth stitch, an air gap through which the needle thread passes is provided between the sewn object and the central presser. In order to prevent the sewn object from floating and fluttering, it is desirable that the amount of rise dto be equal to or larger than the diameter of the needle thread and be as small as possible while being in a range that allows that the needle thread slides through. I.e. in a period until the small hole 122 consistent with the operation of the take-up lever 13 increases to reach top dead center after passing through the shuttle 12 gripped needle thread has been released, the command generating device stops 321 the middle button 15 at a fixed height at the position to which the central pusher moves 15moved by a distance equal to or larger than the diameter of the needle thread from the surface of the sewn object. In this way, the power source drives the central pusher 15 such that he is in a period until the small hole 122 consistent with the operation of the take-up lever 13 increases to reach top dead center after passing through the shuttle 12 gripped needle thread is released, stops at the position to which the center presser moves 15 moved by a distance equal to or larger than the diameter of the needle thread from the surface of the sewn object. Even if the holding device 26 is transported immediately after the sewing needle 11 from the sewn objects Ob1 and Ob2 been pulled out, it is possible in this way to increase the seam tightening effect of a seam using the thread take-up lever 13 to improve since the needle thread passes through the air gap while preventing a situation where the needle thread between the sewn object Ob1 or Ob2 and the central pusher 15 gets caught and becomes frayed or worn out.

[0094] With the drive pattern according to the second embodiment, the time of feeding the sewn articles Ob1 and Ob2 through the holding device 26 , i.e. the drive time of the X-axis motor 21 and the Y-axis motor 22 , to be extended. Especially if the sewing machine 100 is large and the weight of the trolley 25 and the holding device 26 passing through the feed mechanism P2 are driven is high, it is consequently possible to increase the sewing speed of the sewing machine 100 to increase.

[0095] When the thread lever 13 is raised while the sewn items Ob1 and Ob2 through the feeding mechanism P2 be transported in the horizontal direction, the distance between the sewn objects can also be increased Ob1 and Ob2 and the thread lever 13 compared to the case where the transport through the feeding mechanism P2 not carried out can be enlarged. This makes it possible to use the thread lever to tighten the seam 13 to improve. Third embodiment.

[0096] In a third embodiment, a case that the central pusher 15 on non-stretch sewn items Ob1 and Ob2 pushes down, and a case that the center pusher 15 on stretchable sewn items Ob3 and Ob4 pushes down, described when the engine 16 of the center pusher is driven by a pressure control scheme.

[0097] At the sewing machine 100 according to the third embodiment is a control scheme of the engine 16 of the central pusher, which is controlled by the arithmetic circuit 323 to control the motor of the center pusher is changed from a position control scheme to the pressure control scheme when the center pusher 15 on the sewn items Ob3 and Ob4 down. In this way, the control device drives P3 the engine 16 of the center pusher in accordance with a print command signal generated by the command generating device 321 is calculated by printing information about the sewn items Ob3 and Ob4 included in the sewing print data D2 are input, or estimated pressure signals of the sewn objects Ob3 and Ob4 used by a pressure estimation circuit 326 to be appreciated. This way involves the sewing machine 100 according to the third embodiment different from the sewing machine 100 according to the first or second embodiment, a control panel 32B instead of the control panel 32A . Otherwise the sewing machine 100 according to the third embodiment, same as the sewing machine 100according to the first or second embodiment. Therefore, descriptions concerning the same parts are omitted.

[0098] First, the structure of the control panel 32B the sewing machine 100 according to the third embodiment with reference to FIG figure 9 explained. figure 9 is a block diagram showing a control structure of the control panel of the sewing machine according to the third embodiment. As in figure 9 is the control panel 32B composed of the command generating device 321 , the arithmetic circuit 322 for controlling the spindle motor, the arithmetic circuit 323 for controlling the motor of the central pusher, the arithmetic circuit 324 to control the X-axis motor, the arithmetic circuit 325 to control the Y-axis motor and a pressure estimation circuit 326 .

[0099] The command generator 321 the control panel 32B receives inputs of a sewing command signal, a stop signal, and an operation start signal, and then outputs a spindle command signal, a center presser command signal, a print command signal, an X-axis command signal, a Y-axis command signal, and a stop command signal. The print command signal is an electrical signal for determining the torque of the center pusher motor. The print command signal is generated by the command generating device 321 according to the sewing pressure data D2 calculated. The arithmetic circuit 322 for controlling the spindle motor, the arithmetic circuit 324 for controlling the X-axis motor and the arithmetic circuit 325 to control the Y-axis motor of the control board 32B are the same as those of the control panel 32A .

[0100] The arithmetic circuit 323 to regulate the motor of the central pusher of the control panel 32B receives inputs of a center pusher command signal, a center pusher rotation signal, a pressure command signal, and a pressure estimation signal, and then outputs a center pusher operation signal to rotate the motor 16 of the central pusher. The arithmetic circuit 323 for controlling the motor of the central pusher is made up of a subtraction unit 327 , a deviation rejection compensator 328 and a switch 329 .

[0101] The subtraction unit 327 outputs, as a deviation signal, a signal obtained by subtracting the center trigger rotation signal from the center trigger command signal.

[0102] The Deviation Suppression Compensator 328 receives an input of the deviation signal and then outputs a deviation suppression signal to the engine 16 to drive the central pusher in such a way that the deviation signal 0 will. In this way, the deviation suppression compensator includes 328 at least one of a proportional compensator that performs a proportional operation, an integral compensator that performs an integral operation, and a differential compensator that performs a differential operation. In the third embodiment, the offset suppression compensator 328 described as a PI compensator.

[0103] The desk 329 receives inputs of the deviation suppression signal, the pressure command signal and the pressure estimation signal and then outputs the deviation suppression signal until the center pusher 15 descends from the top dead center and in contact with the sewn object Ob3 or Ob4 reached. After the central pusher 15 in contact with the sewn item Ob3 or Ob4 arrived, the switch 329 switched to output the pressure command signal or the pressure estimation signal. In this way, the switch returns 329 the signal to operate the center pusher off to start the motor 16 to drive the central pusher in such a way that the central pusher 15 towards the skid plate 4 on the sewn object Ob3 or Ob4down.

[0104] The switch chooses 329 the print command signal when the sewing print data D2 are set, and it selects the pressure estimation signal when the sewing pressure data D2 are not set. Then the switch 329 switched to output the deviation suppression signal when the center pusher 15 from the sewn object to the top dead center. The motor 16 of the center pusher is driven by the position control scheme when the switch 329 selects the deviation suppression signal and is driven by the pressure control scheme when the switch 329 selects the pressure command signal or the pressure estimation signal.

[0105] The pressure estimation circuit 326 the control panel 32B receives inputs of the center presser operation signal and the center presser rotation signal, and then outputs, as a pressure estimation signal, a signal obtained by estimating the repulsive force of the sewn object when the center presser is pressed 15 comes into contact with the sewn object. In addition, the pressure estimation circuit estimates 326 the disturbance to the rotor of the motor 16 of the central pusher is applied. Therefore includes the pressure estimation circuit 326 an engine characteristic compensator having a transfer function obtained by inverse characteristic of a transfer characteristic from the to the motor 16 of the center pusher applied to the angle of rotation of the motor 16 the center presser is given a low-pass characteristic, a low-pass filter for giving the center presser operation signal the low-pass characteristic, and a subtraction unit which calculates the difference between an output signal of the machine characteristic compensator and an output signal of the low-pass filter.

[0106] With reference to figure 10 will operate the central pusher 15 the sewing machine 100 according to the third embodiment, when pressing down on inextensible sewn articles Ob1 and Ob2 and when pressing down on stretchable sewn items Ob3 and Ob4 consistent with the pressure control scheme described.

[0107] figure 10 is an operation diagram of the center presser of the sewing machine according to the third embodiment. The middle pusher 15 the sewing machine 100 according to the third embodiment, on the in figure 7 or figure 8 is operated as far as the angle of rotation of the spindle motor is concerned. In particular shows figure 10 the operation of the central pusher 15 at the time when the sewing needle 11 on the boat 12 hits, i.e. at the time when the angle of rotation of the spindle motor 14 d and d' is. [Pressing down on non-stretch sewn items]

[0108] Referring to the top section of figure 10 describes a case in which the central pusher 15 in line with the pressure control scheme on the non-stretch sewn items Ob1 and Ob2 down. First, the switch chooses 329 the deviation suppression signal in a period until the center pusher 15 descends to be in contact with the surface of the sewn object Ob1 or Ob2 to get. During this period, the engine 16 of the central pusher driven by the position control scheme. After the central pusher 15 in contact with the surface of the sewn item Ob1 or Ob2 is reached, then the switch 329 switched to the pressure command signal or the pressure estimation signal to drive the motor 16 of the center pusher to be driven by the pressure control scheme. In this way, the sewn items Ob1 and Ob2 through the center button 15 down onto the skid plate 4 pressed. Because the sewn items Ob1and Ob2 are not stretchable, the height of the lowest point of the center presser is at the top of the sewn item Ob1 , when the rotation angle of the spindle motor is d, and it is at the top of the sewn item Ob2 , when the angle of rotation of the spindle motor is d'.

[0109] Whether the central pusher 15 in contact with the sewn item Ob1 or Ob2 reached or not may be determined when the deviation signal converges to 0, or it may be determined when an impulse-like noise is superimposed on the pressure estimation signal or the center pusher operation signal.

[0110] If the central pusher 15 , which is consistent with the in figure 7 or figure 8 is driven, rises to the top dead center after hitting the sewn articles Ob1 and Ob2 pressed down or when it comes off the surfaces of the sewn items Ob1 and Ob2 to dlo increases, the switch 329 switched to select the deviation suppression signal. In this case, the time to switch the switch 329 be determined in accordance with the command signal for the center pusher. In figure 7 becomes the switch 329 switched when the rotation angle of the spindle motor 14 h' and h" is. In figure 8 becomes the switch 329 switched when the rotation angle of the spindle motor 14 e and e' is. [Pressing down on a stretchable sewn object]

[0111] As in the bottom section of figure 10, the position control scheme is first selected when applied to the stretchable sewn articles Ob3 and Ob4 is pushed down. The middle pusher 15 is driven in such a way that it descends until the central pusher 15 in contact with the surfaces of the sewn items Ob3 and Ob4 reached. After the central pusher 15 in contact with the surfaces of the sewn items Ob3 and Ob4 is reached, then the switch 329 switched. The middle pusher 15 is driven to be applied to the sewn articles by means of the pressure control scheme in accordance with the pressure command signal or the pressure estimation signal Ob3 and Ob4 down. Because the sewn items Ob3 and Ob4 are stretchable is the height at which the central pusher 15 reaches the lowest point, different when the rotation angle of the spindle motor is d and when the rotation angle of the spindle motor is d'. When the rotation angle of the spindle motor is d, the height is at the position to which the center pusher 15 by a distance dc1 from the surface of the sewn item Ob3 sinks. When the angle of rotation of the spindle motor is d', the height is at the position to which the center pusher 15 by a distance dc2 from the surface of the sewn item Ob4 sinks. Whether the central pusher 15 comes into contact with the sewn object or not can be determined when the deviation signal converges to 0, or it can be determined when an impulse-like noise is superimposed on the pressure estimation signal and the center presser operation signal.

[0112] If the middle pusher 15 from the position at which the central pusher 15 on the sewn items Ob3 and Ob4 pushes down, rises to top dead center, or when the center pusher 15 from the position at which the central pusher 15 on the sewn items Ob3 and Ob4 depressing to dlo increases, is based on the in figure 7 or figure 8 drive pattern of the switches 329 switched to select the deviation suppression signal. The time when the central pusher 15 rises from the sewn object is similar to the case that the center presser 15 on the non-stretch sewn items Ob1and Ob2 down. [Effects of the third embodiment]

[0113] In this way, at the sewing machine 100 according to the third embodiment, the motor 16 of the central pusher driven in accordance with the position control scheme, while the central pusher 15 falls or rises, and the engine 16 of the center pusher is driven in accordance with the torque control scheme, while the center pusher 15 presses down on the sewn object. In this way, even when sewing a stretchable sewn article in one cycle of up and down movement of the needle bar, it is possible to lengthen the period during which the center presser accurately presses down various stretchable sewn articles without using a machine component that a spring is represented, i.e. a machine element that accumulates elastic energy using the restoring force of an elastic body. As in figure 7 shown based on the first embodiment, it is possible, especially when the central pusher 15 down on the sewn object while the thread take-up lever 13 from bottom dead center to top dead center increases to improve seam tightness of seams formed in various stretchable sewn articles.

[0114] Note that the pressure estimation signal may be a signal obtained by directly detecting a repulsive force of the sewn object by using the pressure estimation circuit instead 326 using a pressure sensor such as a force transducer or piezoelectric element mounted on the central pusher 15 or the sewn objects Ob3 and Ob4 is attached.

[0115] A torque sensor mounted on the rotor of the motor can be used to estimate the repulsion force of the sewn object 16 of the central pusher is attached.

[0116] To estimate the repulsive force of the sewn object, a value of the to a winding wire of the motor 16 of the central pusher can be measured by a current sensor composed of a Hall element and a shunt resistor.

[0117] Instead of the switch 329 an output limiter can be used which receives inputs of the deviation suppression signal, the pressure command signal and the estimated pressure signal and limits the output of the second drive source to a fixed value so that the deviation suppression signal becomes equal to the pressure command signal or the estimated pressure signal. In this case, the output limiter outputs the deviation suppression signal directly without limiting the output until the center pusher 15 falls and comes into contact with the sewn object. After the central pusher 15 has come into contact with the sewn object, the output limiter then limits the output to prevent the deviation suppression signal from exceeding the pressure command signal or the estimated pressure signal. In this way it is possible to drive the engine 16 of the central pusher so that the central pusher 15 presses down on the sewn item with a fixed pressure. Compared to the case that the switch 329 is used, it is possible to reduce a sudden change in the center pusher operation signal due to the switching of the control scheme.

[0118] In the event that the distances dc1 and dc2 are larger than dlo, the needle thread can be loosened due to the restoring force of the sewn items Ob3 and Ob4 , which is pressed down, between the central pusher 15 , which increased by dlo, and the sewn item Ob3 or Ob4 get stuck. If the jig is transported in this situation and the needle thread becomes frayed or worn out, it is sufficient if the center pusher is pressed 15 is caused to dlo from the surfaces of the sewn items Ob3 and Ob4to rise, and not starting from the position in which the central presser on the sewn items Ob3 and Ob4 down.

[0119] When the sewn item is extra soft and there is no problem even if the center presser 15 stops due to collision with the sewn object, it is possible that the amount of sinking lo and lo' of the center presser 15 is not necessarily determined in advance, the engine 16 of the central pusher can be driven in such a way that the central pusher 15 at a fixed height in relation to the top of the skid plate 4 , which is the rack, or the feed plate 29 stops. By setting a stop position of the center presser using the frame on which the sewn object is placed as a reference when a sewn object is particularly soft, it is possible to reduce labor and time required are, by the amount of sinking lo and lo' of the central pusher 15 to be determined according to the thickness of the sewn object.

[0120] The command generating device generates a drive signal for the drive source to stop the center presser at a fixed height at the position where the center presser is sewn with a specific pressure in a period until the small hole rises and reaches the top dead center object down. In this way, the drive source drives the center presser such that the center presser stops at the position where the center presser presses down the sewn object with the specific pressure in a period until the small hole rises and reaches the top dead center . In this way, it is possible to prevent various compressible sewn articles from floating and fluttering.

[0121] The command generating device generates a drive signal for the drive source to stop the center pusher in the period until the small hole rises and reaches the top dead center at a fixed height at the position to which the center pusher moves by a distance equal to is equal to or larger than the diameter of the needle thread from the position where the center presser presses down the sewn object with the specific pressure. In this way, the drive source drives the center presser such that the center presser stops at the position to which the center presser has moved by a distance equal to or larger than the diameter of the needle thread from the position on which the central presser presses down with the specific pressure on the sewn object. In this way, it is possible to prevent various compressible sewn articles from floating and fluttering. Further, it is possible to increase the period during which the positioning unit can convey the sewn object.

[0122] The specific pressure is calculated using one or more of a pressure sensor attached to the sewn object, a pressure sensor attached to the center presser, and a sensor for detecting a state quantity of the driving source. By using these sensors it is possible to improve the reliability of the pressure control scheme.

[0123] As explained above, the sewing machines 100 according to the first to third embodiments constructed so as to generate a drive signal for the drive source to press the center presser during a period in which the small hole increases according to the operation of the thread take-up lever after releasing the needle thread caught by the shuttle in a to stop at a fixed height. With this construction, it is possible to improve the seam tightness of a seam formed in the sewn article by changing the operation of the center presser.

[0124] The configurations explained above with reference to the first to third embodiments give examples of the context of the present invention. The configurations can be combined with other publicly known technologies. Parts of the configurations may be omitted or changed within a range that does not depart from the gist of the present invention. Reference List

[0125] 1 Poor; 2 Bed; 3 supporting leg; 4 sliding plate; 11 sewing needle; 13 thread lever; 14 spindle motor; 15 central pusher; 16 Central pusher motor; 17 thread tension adjuster; 18 , 27 , 28 , 124 rotation information detector; 19 upper shaft; 21 X-axis motor; 22 Y-axis motor; 23 X-axis drive mechanism; 24 Y-axis drive mechanism; 25 trolley; 26 holding device; 29 feed plate; 31 control panel; 32A , 32B control panel; 33 foot switch; 100 Sewing machine; 110 Coupling; 111 Crank; 112 needle bar crank; 113 Connecting rod; 115 needle bar; 116 Upper shaft pulley; 117 drive belts; 118 Lower shaft pulley; 119 large diameter gear; 120 small diameter gear; 121 lower shaft; 122 small hole; 123 thread lever rod; 125 Pinion; 126 rack; 127 sliding guide; 128 slider; 130 Central pusher bar; 210 outer pusher; 211 press table; 212 air cylinder; 311 Advertisement; 312 Processor; 313 storage device; 314 input device; 321 command generating device; 322 Arithmetic circuit for controlling the spindle motor; 323 Arithmetic circuit for controlling the motor of the central pusher; 324 Arithmetic circuit to control the X-axis motor; 325 Arithmetic circuit to control the Y-axis motor; 326 pressure estimation circuit; 327 subtraction unit; 328 deviation suppression compensator; 329 Switch. QUOTES INCLUDED IN DESCRIPTION

[0000] This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Patent Literature Cited

[0000] JP 2010148551

[0006] JP H838763

[0006] JP H11128576

[0006]

Claims

[1] Sewing machine, including: a sewing needle which has an eye through which a needle thread is inserted; a shuttle which includes a point to grasp the needle thread, in order to interlace the needle thread and a bobbin thread; a thread lever having a small hole through which the needle thread is inserted, the thread lever lifting the needle thread from a sewn object, which is a sewing target, in accordance with the rise of the small hole from a bottom dead center to a top dead center; a central push button to prevent the sewn item from floating; and a drive source to drive the central pusher in such a way that the central pusher is stopped at a fixed height during a period in which the small hole rises in accordance with an operation of the thread lever after the needle thread caught by the shuttle has been released. [2] Sewing machine according to claim 1, wherein the drive source drives the central pusher such that the central pusher stops at a fixed height relative to the top of a frame on which the sewn object is located for a period of time until the small hole rises in accordance with an operation of the thread lever and reaches top dead center after the needle thread caught by the shuttle has been released. [3] Sewing machine according to claim 1, wherein the drive source drives the central pusher such that the central pusher stops at a fixed height relative to a surface of the sewn object for a period of time until the small hole rises in accordance with an operation of the thread lever and reaches the top dead center after the needle thread caught by the shuttle has been released. [4] Sewing machine according to claim 1, wherein the drive source drives the central pusher such that the central pusher stops at a position, for a period of time until the small hole rises in accordance with an operation of the thread lever and reaches the top dead center after the needle thread caught by the shuttle has been released, to which the central pusher moves by a distance equal to or greater than a diameter of the needle thread from a surface of the sewn object. [5] Sewing machine according to claim 1, wherein the drive source drives the central pusher such that the central pusher stops at a position in which the central pusher presses down on the sewn object with a specific pressure during a period of time until the small hole rises in accordance with an operation of the thread lever and reaches the top dead center after the needle thread caught by the shuttle has been released. [6] Sewing machine according to claim 1, wherein the drive source drives the central pusher such that the central pusher stops at a position, for a period of time until the small hole rises in accordance with an operation of the thread lever and reaches the top dead center after the needle thread caught by the shuttle has been released, to which the central pusher moves by a distance equal to or greater than a diameter of the needle thread from a position at which the central pusher presses down on the sewn object with a specific pressure. [7] Sewing machine according to claim 5 or 6, wherein the specific pressure is calculated by using one or more pressure sensors attached to the sewn item, pressure sensors attached to the central pusher and sensors for detecting a state variable of the drive source.