JP2010131175A - Sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the thickness of a workpiece while reducing the number of components and securing a space around a needle bar. <P>SOLUTION: The sewing machine includes: a sewing machine motor 2a for vertically moving a sewing needle 108; a center presser foot 29 for preventing the floating of the workpiece during sewing; a center presser foot vertically moving mechanism M1 for vertically moving the center presser foot in synchronism with the sewing needle; a center presser foot height adjusting mechanism M4 for adjusting the bottom dead center height of the center presser foot by a center presser foot motor 42; center presser foot height control means 73 for controlling the center presser foot motor so as to stop the center presser foot by pressurization during the lowering contact of the center presser foot; and thickness acquisition processing means 73 for obtaining the thickness of the workpiece from the height of the center presser foot at the state change time of the output shaft of the center presser foot motor by the lowering contact of the center presser foot. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sewing machine having an intermediate presser.

In conventional sewing machines, the sewing product is pressed by an intermediate presser that moves up and down with a smaller stroke than the sewing needle so that the sewing product is not pulled by the sewing needle that moves up. Since the vertical movement is performed at a low position, in the case of a thick sewing product, there is a problem that the sewing product is stepped on when the intermediate presser is lowered.
Therefore, a conventional sewing machine is provided with a stepping motor that adjusts the vertical position of the intermediate presser by moving the intermediate presser up and down separately from the sewing machine motor, and a cloth thickness detector composed of an optical element. Based on this, control is performed to adjust the bottom dead center height of the intermediate presser by the stepping motor (see, for example, Patent Document 1).
Japanese Examined Patent Publication No. 7-44983 (Fig. 5)

However, in the conventional sewing machine in Patent Document 1, the cloth thickness detector composed of optical elements cannot detect the cloth thickness when compressed by the seam during sewing, and the detection accuracy is low. The height control was also of low accuracy. In addition, there is a problem that a dedicated cloth thickness detector is indispensable and the productivity is lowered due to an increase in the number of parts. The cloth thickness detector must be placed around the needle bar where the item to be sewn is located, but in a sewing machine equipped with an intermediate presser, the intermediate presser and its vertical movement mechanism are provided. There is also a problem that it is difficult to secure a space for arranging the cloth thickness detector.
Further, the conventional sewing machine has a problem that even if the cloth thickness can be obtained, it cannot be obtained by the hardness of the cloth.
The present invention reduces the number of parts and makes it possible to accurately and automatically detect the fabric thickness at the time of forming the seam, excluding the wipe, while allowing a wide space around the needle bar to be secured. And its purpose.

  According to the first aspect of the present invention, there is provided a needle up-and-down moving mechanism for moving a sewing needle up and down by a sewing motor, a spindle angle detecting means for detecting an angle of a spindle driven to rotate by the sewing machine motor, and lifting of a sewing object during sewing. An intermediate presser and a middle presser vertical movement mechanism that obtains power from the sewing machine motor and moves the intermediate presser up and down in synchronization with the vertical movement of the sewing needle, and the intermediate presser vertical movement mechanism by an intermediate presser motor. In the sewing machine comprising an intermediate presser height adjusting mechanism for moving the bottom dead center height of the intermediate presser up and down, the intermediate presser is provided with motor shaft angle detecting means for detecting the angle of the output shaft of the intermediate presser motor and is lowered. The intermediate presser height control means for performing variable height control for reducing the torque of the intermediate presser motor to be lower than when it is raised so that it can be stopped by the pressing force at the time of contact with the workpiece by During variable control, when the change in the angle of the output shaft of the intermediate presser motor is detected because the intermediate presser is in contact with the workpiece and stopped descending halfway, the height of the intermediate presser corresponding to the angle change is detected. A thickness acquisition processing means is provided for performing a thickness acquisition process for determining the thickness of the sewing product.

  The invention according to claim 2 has the same configuration as that of the invention according to claim 1, and after obtaining the thickness of the sewing product in the height variable control, The intermediate presser pressing control means for performing the press control for gradually changing the torque value of the intermediate presser motor so that the contact pressure increases, and the lowering of the intermediate presser is detected by the motor shaft angle detecting means during the execution of the press control. In this case, it comprises a hardness acquisition processing means for recording the torque value of the intermediate presser motor at the time of lowering or the hardness of the sewing product obtained from the torque value.

  The invention according to claim 3 has the same configuration as that of the invention according to claim 2, and the hardness acquisition processing means is based on the acquired torque value of the intermediate presser motor or the hardness of the sewing product. At least one of the setting of the yarn tension of the yarn tension adjusting means and the torque of the sewing machine motor is corrected.

In the first aspect of the invention, when the intermediate presser is lowered, the height variable control is performed so that the torque output is reduced so that the pressure at the time of contact with the sewing product is smaller than that at the time of the rise. When it comes into contact with the sewing product, it is defeated by the contact pressure received from the sewing product side, and the lowering operation of the intermediate presser is stopped.
Since the output shaft of the intermediate presser motor changes in angle due to the stoppage of the intermediate presser, the motor shaft angle detection means can detect the occurrence of contact between the intermediate presser and the workpiece, The height can be obtained from the detection angle of the presser, and the thickness of the workpiece can be obtained.
Further, in the above invention, since the thickness of the sewing product is detected by bringing the intermediate press into contact with the sewing product, it is possible to detect an accurate cloth thickness that suppresses the wiping of the sewing product.

According to the first aspect of the present invention, there is a case where the thickness of the workpiece is detected during an actual sewing operation, and the vertical movement of the intermediate presser for maintaining the sewing by only the intermediate presser motor without driving the sewing machine motor. Both cases where the thickness of the workpiece is detected during teaching to reproduce the operation are assumed (the same applies to claims 2 and 3). In the case of actual sewing, when the intermediate presser is lowered, the intermediate presser motor keeps the output shaft constant so that the output shaft does not rotate, and the holding torque has a size that cannot resist the pressing force generated at the time of contact ( By making it smaller than the holding torque of the intermediate presser motor at the time of ascent), the output shaft of the intermediate presser motor is caused to rotate when contacting the workpiece.
In the case of teaching, the intermediate presser is moved up and down only by driving the intermediate presser motor, so that the driving torque in the downward direction cannot withstand the pressing force generated at the time of contact (the intermediate presser motor when it is raised) Therefore, the output shaft of the intermediate presser motor is caused to rotate at the time of contact with the workpiece.
Therefore, the “angle change of the output shaft” by the thickness acquisition processing means indicates the time when a change of [output shaft stop → output shaft rotation] occurs in actual sewing, and in the case of teaching, The time when a change of [output shaft rotation → output shaft stop] occurs is shown.

  In addition, here, “to reduce the torque of the intermediate presser motor so that it can be stopped by the pressing force at the time of contact with the sewing product than when it is increased” means that the intermediate presser is lowered by the sewing machine motor (actual operation ) Means that when the intermediate presser is pressed against the workpiece by the power of the sewing machine motor, the holding torque of the intermediate presser motor is lost against the press contact force and rotates in the upward movement direction to cancel the vertical movement of the intermediate presser. When the intermediate presser is lowered by the intermediate presser motor (in the case of teaching), the drive torque during the downward movement of the intermediate presser motor is controlled as much as possible to reduce or eliminate the generation of contact pressure. To tell.

According to the above invention, the thickness of the workpiece can be obtained without using a cloth thickness detector that performs contact position detection, distance detection, and the like, and productivity can be improved by reducing the number of parts. Further, since the press at the time of contact with the sewing product by the intermediate presser is reduced by the intermediate presser motor, it is possible to avoid damaging the sewing product by pressing, and the sewing quality can be improved by protecting the sewing product. It becomes possible.
In the present invention, the cloth thickness detector can be omitted, but the motor shaft angle detecting means of the intermediate presser motor is essential. However, the motor shaft angle detection means of the intermediate presser motor is not limited to the cloth thickness detection, and is highly versatile.For example, it is possible to monitor the operation control and deviation to prevent the intermediate presser motor from stepping out. Since it can be used in combination with other applications such as power saving control such as switching between large and small, the number of parts does not increase by using the motor shaft angle detection means for these applications. Furthermore, since it is only necessary to detect the shaft angle of the output shaft of the intermediate presser motor, there is no need to provide it around the needle bar unlike the cloth thickness detector, and it is possible to secure a wide space around the needle bar as a work space. At the same time, it does not prevent other mechanisms and members from being mounted around the needle bar of the sewing machine.

The execution section of the variable height control is not limited to the entire range of the lowering operation of the intermediate presser, but only the section that can contact the workpiece, and the section that cannot contact the workpiece (for example, the sewing target to be sewn) For the height that cannot be touched with the thickness of the intermediate press), the intermediate presser motor is controlled to have a normal torque that can maintain the bottom dead center of the intermediate presser (torque of the same magnitude as when it is raised) The height variable control may be started after the section that cannot be in contact with the workpiece is removed.
In addition, the torque of the intermediate presser motor in the variable height control is preferably 0 or reduced as much as possible to reduce the contact pressure to the workpiece by the intermediate presser. Pressure may be generated.
In addition, the “height variable control” and the “thickness acquisition process” may be performed on the intermediate presser that performs the lowering operation during actual sewing, or the lowering operation during the reproduction operation (teaching) described later. You may carry out with respect to the intermediate presser which performs.

According to the second aspect of the present invention, when the thickness of the sewing product is obtained in the height variable control, torque control of the intermediate presser motor is performed so that the contact pressure to the sewing product by the intermediate presser is increased. When the contact pressure of the intermediate presser that has been defeated by the workpiece is increased to a certain degree by torque control, the workpiece can be lowered while being depressed. Since the torque value at that time has a certain correspondence with the hardness of the sewing product, the hardness of the sewing product is obtained and recorded from the torque value or the torque value, so that it corresponds to the hardness of the sewing product. It can be applied to various types of control.
In the above-described control, torque control is performed so as to gradually increase the holding torque in the case of actual sewing and gradually increase the driving torque in the downward direction in the case of teaching.
The torque itself may be recorded, or the hardness may be obtained. However, when the hardness is obtained, the relationship between the torque value and the hardness of the sewing product is obtained in advance by measurement or the like and stored. The table may be used, or the correspondence relationship may be expressed as a mathematical expression.
In addition, the hardness of the sewing product can be obtained without using a hardness detecting means including a dedicated sensor for obtaining the hardness of the sewing product, and the productivity is improved by reducing the number of parts. Is possible.
In the present invention, a dedicated hardness detecting means is not required, but a motor shaft angle detecting means for the intermediate presser motor is essential. However, as described above, the motor shaft angle detection means of the intermediate press motor is highly versatile, so that the number of parts of the sewing machine that the motor shaft angle detection means is necessary for other uses is small. There is no increase. Furthermore, it is only necessary to be able to detect the shaft angle of the output shaft of the intermediate presser motor, so there is no need to provide it around the needle bar as in the case of dedicated hardness detection means, and it is possible to secure a wide working space around the needle bar. At the same time, it does not prevent other mechanisms and members from being mounted around the needle bar of the sewing machine.

  The invention according to claim 3 corrects the set thread tension of the thread tension adjusting means or the torque of the sewing machine motor based on the acquired torque value of the intermediate presser motor or the hardness of the sewing product. It is possible to optimize the thread tension or the torque of the sewing machine motor according to the hardness, and it is possible to improve the sewing quality.

Hereinafter, embodiments of a sewing machine according to the present invention will be described in detail with reference to the drawings.
In the present embodiment, an electronic cycle sewing machine will be described as an example of the sewing machine.
The electronic cycle sewing machine has a holding frame that holds a cloth that is a sewing object to be sewn, and the holding frame moves relative to the sewing needle, so that a predetermined sewing is performed on the cloth held by the holding frame. The sewing machine forms a seam based on pattern data (sewing pattern).
Here, the direction in which the sewing needle 108 described later moves up and down is the Z-axis direction (up-and-down direction), and one direction orthogonal to this is the X-axis direction (left-and-right direction). The direction perpendicular to the Y axis direction is defined as the Y-axis direction (front-rear direction).

  As shown in FIG. 1, an electronic cycle sewing machine 100 (hereinafter referred to as a sewing machine 100) is provided with a sewing machine main body 101 provided on the upper surface of the sewing machine table T and a lower part of the sewing machine table T, and operates the start and stop of sewing. A pedal R for operation, an operation panel 74 provided on an upper part of the sewing machine table T for performing an input operation by a user, and the like.

(Sewing frame and spindle)
As shown in FIGS. 1 and 2, the sewing machine main body 101 includes a sewing machine frame 102 whose outer shape is substantially U-shaped in a side view. The sewing machine frame 102 has an upper part of the sewing machine body 101 and extends in the front-rear direction, a sewing machine bed part 102 b that forms the lower part of the sewing machine body 101 and extends in the front-rear direction, and the sewing machine arm part 102 a and the sewing machine bed part 102 b. And a vertical body portion 102c that connects the two.
The sewing machine main body 101 includes a main shaft 2 (see FIG. 4) and a lower shaft (not shown). The main shaft 2 is disposed inside the sewing machine arm portion 102a, and the lower shaft (not shown) is disposed inside the sewing machine bed portion 102b.

The main shaft 2 is connected to a sewing machine motor 2a (see FIG. 8), and rotational power is applied by the sewing machine motor 2a. The lower shaft (not shown) is connected to the main shaft 2 via a vertical axis (not shown). When the main shaft 2 rotates, the power of the main shaft 2 is transmitted to the lower shaft side via the vertical axis. The lower shaft rotates.
A needle bar 108a that moves up and down in the Z-axis direction by the rotation of the main shaft 2 is connected to the front end of the main shaft 2, and a sewing needle 108 is replaceably provided at the lower end of the needle bar 108a. That is, the sewing needle 108 moves up and down in the Z-axis direction as the main shaft 2 rotates.
The needle vertical movement mechanism is constituted by the main shaft 2, the sewing machine motor 2a, the needle bar 108a, and a transmission mechanism (not shown) that applies a driving force for vertical movement from the main shaft 2 to the needle bar 108a.

  The main shaft 2 is provided with an encoder 2b (see FIG. 7) as main shaft angle detecting means. The encoder 2b detects the rotation angle of the main shaft 2 of the sewing machine motor 2a. For example, the encoder 2b outputs a pulse signal to the control device 1000 every time the main shaft 2 rotates 1 ° by the sewing machine motor 2a. Further, as the main shaft 2 rotates once, the needle bar 108a performs one reciprocating motion.

A hook (not shown) is provided at the front end of the lower shaft (not shown). When the lower shaft rotates together with the main shaft 2, a seam is formed by the cooperation of the sewing needle 108 and the shuttle (not shown).
The connection configuration of the sewing machine motor 2a, the main shaft 2, the needle bar 108a, the sewing needle 108, the lower shaft (not shown), the shuttle (not shown) and the like are the same as those conventionally known and will not be described in detail here.

(Positioning means)
As shown in FIGS. 1 and 2, a needle plate 110 is disposed on the sewing machine bed portion 102 b, and a holding frame 111 and a sewing needle 108 as a cloth holding portion are disposed above the needle plate 110. It has become so.
The holding frame 111 is attached to an attachment member 113 disposed at the front end of the sewing machine arm portion 102a. The attachment member 113 has an X-axis motor 76a and a Y-axis as positioning motors arranged in the sewing machine bed 102b. A motor 77a is connected as drive means (see FIG. 7).
The holding frame 111 holds the cloth that is the sewing object, and moves the held cloth in the front-rear and left-right directions together with the holding frame 111 as the X-axis motor 76a and the Y-axis motor 77a are driven. Then, the movement of the holding frame 111 and the operation of the sewing needle 108 and the hook (not shown) are interlocked to form a seam based on the seam data of predetermined sewing pattern data on the fabric.
The holding frame 111 includes a cloth presser (not shown) and a lower plate (not shown), and the mounting member 113 can be driven up and down by driving a cloth presser motor 79b disposed in the sewing machine arm 102a. Yes, the fabric is clamped and held between the lower plate when the fabric presser is lowered.
The holding frame 111, the mounting member 113, the X-axis motor 76a, and the Y-axis motor 77a function as a positioning mechanism that relatively positions the sewing needle and the fabric in the X-axis direction and the Y-axis direction.

  The pedal R operates as an operation pedal for driving the sewing machine 100 and moving the needle bar 108a (the sewing needle 108) up and down and operating the holding frame 111. That is, the pedal R incorporates a sensor for detecting the depression operation position when the pedal R is depressed, and an output signal from the sensor is output as an operation signal of the pedal R to the control device 1000 described later, and the control is performed. The apparatus 1000 is configured to drive and operate the sewing machine 100 according to the operation position and operation signal.

In addition, the sewing machine 100 is provided with an operation panel 74 for performing an operation input by a user, and various data and operation signals input to the operation panel 74 are output to a control device 1000 described later.
The operation panel 74 includes a liquid crystal display panel and a touch panel provided on the display screen of the liquid crystal display panel, and is operated by touching various operation keys displayed on the liquid crystal display panel. The position where the touch panel is touched is detected, and an operation signal corresponding to the detected position is output to the control device 1000 described later.

(Medium holding device)
In order to prevent the cloth from being lifted by the vertical movement of the sewing needle 108, the sewing machine arm 102a moves up and down in conjunction with the vertical movement of the needle bar 108a and presses the cloth around the sewing needle 108 downward. An intermediate pressing device 1 having 29 (see FIG. 3) is provided. Note that the main body of the intermediate presser 1 is disposed inside the sewing machine arm portion 102 a, and the sewing needle 108 is inserted into a through hole formed on the distal end side of the intermediate presser 29.
As shown in FIGS. 3 to 5, the intermediate presser 1 includes an intermediate presser 29 that presses the cloth against the needle plate 110 during sewing and a sewing presser 108 that moves up and down by the rotation of the main shaft 2. An intermediate presser vertical movement mechanism M1 that moves up and down, an urging mechanism M2 that enables the escape operation that is performed when the lowering operation of the intermediate presser 29 is inhibited and that urges the intermediate presser 29 toward the needle plate 110 during the escape operation The intermediate presser retracting mechanism M3 that raises the intermediate presser 29 to the retracted height position after the end of sewing and the intermediate presser height adjusting mechanism M4 that adjusts the height of the intermediate presser 29 are provided.

The intermediate presser vertical movement mechanism M1 moves the intermediate presser 29 up and down by the rotation of the main shaft 2 (see FIG. 4) that drives the needle bar 108 having the sewing needle 108 at the tip in the vertical direction.
As shown in FIG. 4, an eccentric cam 3 is fixed to the main shaft 2, and a connection link 4 is connected to the eccentric cam 3. A rocking shaft holder 5 is connected to the connection link 4, and one end of the rocking shaft 6 is connected to the rocking shaft holder 5.
As shown in FIG. 5, the base end portion of the intermediate presser adjustment arm 7 that adjusts the amount of movement of the intermediate presser in the vertical direction D <b> 1 is fixed to the other end portion of the swing shaft 6. A groove cam 7 a is formed on the intermediate presser adjusting arm 7. The groove cam 7a is an arc-shaped long hole, and one end of the first link 8 is pivotally supported by an adjusting nut 9 and a step screw 10 at a desired position of the groove cam 7a. The fixed position of the one end portion of the first link 8 can be adjusted toward and away from the center of the swing shaft 6, and the amount of reciprocating motion applied to the first link 8 is increased or decreased in proportion to the distance from the center. be able to.

As shown in FIG. 5, the other end of the first link 8 is connected to the middle of the second link 11 in the longitudinal direction by a step screw 12 so as to be rotatable. Here, the groove cam 7a with which the adjusting nut 9 is engaged is formed so as to be a part of an arc centered on the axis of the step screw 12 when the intermediate presser 29 is at the bottom dead center of the vertical reciprocation. Has been. In other words, by adjusting the position of the first link 8 in the cam groove 7a when the angle of the upper shaft 2 is in a phase for moving the intermediate presser 29 to the bottom dead center, the bottom dead center position of the intermediate presser 29 is fixed. Stroke adjustment can be performed as it is.
However, since the sewing machine 10 performs processing for calculating the thickness of the sewing product from the height of the intermediate presser 29 when it contacts the sewing product, as will be described later, the stroke is related to the calculation. Therefore, do not make any adjustments. Further, when adjusting, it is necessary to set and input the stroke value as a parameter for calculating the thickness of the sewing product into the control device 1000 and update it.

  And the one end part of the 2nd link 11 is pivotally supported by the positioning link 13 mentioned later. When one end of the second link 11 is pivotally supported by the positioning link 13 and the intermediate presser 29 moves up and down during normal sewing, the one end of the second link 11 is caused by the elastic force of the tension spring 16. Is kept pressed against the regulating member 19. When the intermediate presser 29 cannot be lowered to the planned bottom dead center position by stepping on the fabric or being caught by something, the positioning link 13 rotates against the elastic force of the tension spring 16, and The fulcrum at one end of the two links 11 descends against the tension spring 16 so that the intermediate presser 29 can escape upward. As a result, the intermediate presser vertical movement mechanism M1 is prevented from being damaged.

As shown in FIG. 5, the other end of the second link 11 is rotatably connected to one end of the third link 20 by a step screw 21. One end of the fourth link 22 is rotatably connected to the other end of the third link 20 by a step screw 23 so as to be in series with the longitudinal direction of the third link 20. In the present embodiment, the third link 20 and the fourth link 22 constitute an intermediate presser link member 24.
A link relay plate 25 is connected to the other end of the fourth link 22 by a step screw 26. An intermediate presser bar holder 27 is fixed to the link relay plate 25, and an intermediate presser bar 28 extending in the vertical direction is held on the intermediate presser bar holder 27. An intermediate presser 29 is attached to the lower end of the intermediate presser bar 28 to press the fabric against the needle plate 110 during sewing. A pressing spring 30 is provided at the upper end portion of the intermediate presser bar 28 and is attached to the intermediate presser bar holder 27 by a bolt 31 and a nut 32. The pressing spring 30 always presses the intermediate presser 29 downward when the intermediate presser 29 moves up and down in synchronization with the sewing needle 108 during sewing.
In the present embodiment, the first link 8, the second link 11, the third link 20, the fourth link 22, and the like constitute an intermediate presser vertical movement mechanism M1.

  The step screw 23 connects the third link 20 and the fourth link 22 together with the square piece 33 and the guide member 34. That is, a guide member 34 is provided on the front side of the fourth link 22, and a square piece 33 is provided on the front side of the guide member 34, and the third link 20, the fourth link 22, the square piece 33, and A guide member 34 is connected by one step screw 23.

  The guide member 34 is a substantially F-shaped plate member, and an upper end portion 34t is rotatably attached to the sewing machine casing (sewing machine frame 102) by a step screw 35. In the vicinity of the lower end portion of the guide member 34, a long hole 34a elongated in the vertical direction is formed. The long hole 34 a is fitted with a square piece 33 slidably inside, and the guide member 34 can move the connecting portion P of the third link 20 and the fourth link 22 in the vertical direction D 1 of the intermediate presser 29. And the movement of the third link 20 and the fourth link 22 in the direction D3 across the series direction D2 is restricted.

Further, as shown in FIG. 5, the guide member 34 has an end portion of a moving link 36 that moves the guide member 34 in a direction D <b> 3 across the series direction D <b> 2 of the third link 20 and the fourth link 22. 37 is rotatably connected to the vicinity of the upper portion of the long hole 34a. An eccentric cam 38 is connected to the other end of the moving link 36, and one end of a variable shaft 39 is connected to the eccentric cam 38.
As shown in FIG. 4, the other end of the variable shaft 39 is connected to an intermediate presser motor 42 via a bearing 40 and a bevel gear 41. That is, the driving of the intermediate presser motor 42 is transmitted in the order of the variable shaft 39, the eccentric cam 38, and the moving link 36, and the moving link 36 changes and adjusts the inclination of the rotation angle of the guide member 34.
The intermediate presser motor 42 is rotatable in forward and reverse directions, and the amount of rotation and the drive timing can be controlled by the control device 1000.
The moving link 36, the guide member 34, the square piece 33, and the like are configured as an operation transmission member of the intermediate presser vertical movement mechanism, and the intermediate presser described later by changing the inclination of the operation transfer member by the intermediate presser motor 42. It functions as an intermediate presser height adjusting mechanism M4 that adjusts the bottom dead center height of 29.

The positioning link 13 is rotatably attached to a sewing machine frame 102 as a sewing machine case by a step screw 14 in the vicinity of the center thereof, and the position of the step screw 14 is the step screw when the intermediate presser 29 is at the bottom dead center. 12 positions are coincident with each other.
One end of the positioning link 13 is folded back in a substantially U shape toward the sewing machine surface, and a spring hook 13a is formed at the folded tip. The positioning link 13 in this embodiment has a spring hook 13a at one end thereof folded back to the vicinity of the step screw 14 that is the rotation center of the positioning link 13, and the distance from the rotation center to the spring hook 13a is shortened. It is formed as follows. One end (upper end) of the tension spring 16 is connected to the spring hook 13a, and the other end (lower end) of the tension spring 16 is connected to a spring hook 15 fixed to the sewing machine frame.
The tension spring 16 urges the one end of the positioning link 13 on which the spring hook 13a is formed to be lowered. That is, the tension spring 16 is connected when the connection portion of the second link 11 with the third link 20 receives a reaction force and receives an upward reaction force due to the occurrence of stepping by the intermediate presser 29. Energize to pull the part down. That is, the tension spring 16 and the positioning link 13 enable the intermediate presser vertical movement mechanism M1 to perform an escape operation for avoiding an excessive load when the lowering operation of the intermediate presser 29 is inhibited, and the intermediate presser 29 is moved to the needle plate during the escape operation. It functions as an urging mechanism M2 that urges to the 110 side. The tension spring 16 functions as a pressing spring for avoiding excessive load.
The urging mechanism M2 is connected to the intermediate presser vertical movement mechanism M1 by connecting the positioning link 13 to the second link 11.

  A stopper 17 is connected to the other end of the positioning link 13, and one end of the second link 11 and the other end of the positioning link 13 are connected by a single stepped screw 18. The stopper 17 is rotatably attached to the sewing machine frame 102 together with the positioning link 13 by a step screw 14. A restricting member 19 is provided above the one end portion 17 a of the stopper 17 so as to restrict the upward movement of the one end portion of the stopper 17. The restricting member 19 may be replaced with a part of the sewing machine frame 102.

  As shown in FIG. 4, a bevel gear 43 is engaged with the bevel gear 41, and the drive of the intermediate pressing motor 42 can be output in a direction D <b> 4 orthogonal to the axial direction of the variable shaft 39. ing. A bearing 44, an intermediate presser raising / lowering cam 45, and the like are coaxially connected to the rear end of the bevel gear 43.

The intermediate presser raising / lowering cam 45 is a groove cam having a groove (not shown) on its axial end face.
The groove of the intermediate presser raising / lowering cam 45 is a cam portion, and half of the rotation range of the intermediate presser raising / lowering cam 45 is formed in an arc shape whose distance from the center of rotation to the groove is substantially the same (hereinafter referred to as an arc shape). The remaining half is a shape in which the distance from the rotation center to the groove is larger than the distance from the rotation center to the groove in the maintenance part and changes smoothly (hereinafter referred to as a change part). It has become.
This intermediate presser raising / lowering cam 45 moves up and down one end portion 46a of the intermediate presser raising member 46 that raises the intermediate presser 29 to the retracted position after the sewing is completed. A cylindrical roller 47 provided at the other end of the intermediate presser lifting member 46 is slidably fitted. When the roller 47 moves along the maintaining portion of the intermediate presser raising / lowering cam 45, the one end portion 46a of the intermediate presser lifting / lowering member 46 does not move up / down, but the roller 47 moves along the changing portion of the intermediate presser lifting / lowering cam 45. When moving, the one end 46a of the intermediate presser lifting member 46 moves up and down.
Since the other end portion of the presser lifting member 46 is engaged with the inner side of the groove (not shown) of the intermediate presser raising / lowering cam 45 which is such a groove cam via the roller 47, the intermediate presser raising / lowering cam 45 rotates. As long as there is no limit, the intermediate presser lifting member 46 does not swing and can maintain a constant state. The intermediate presser raising / lowering cam 45, the intermediate presser lifting member 46, and the roller 47 constitute an intermediate presser retracting mechanism M3.

  The intermediate presser lifting member 46 is rotatably attached to and supported by the sewing machine frame 102 by a shaft member, that is, a pin 48 at its middle abdomen. The intermediate presser lifting member 46 is provided so that one end portion 46a thereof is positioned below the intermediate presser bar holder 27, and the roller 47 moves along the changing portion of the intermediate presser raising / lowering cam 45 so that the intermediate presser lifter 46 is moved. When the one end 46a of the member 46 is raised, the intermediate presser bar holder 27 can be raised, and the intermediate presser 29 can be raised to the retracted position.

(Operation of the intermediate presser during sewing)
Next, the operation of the intermediate presser vertical movement mechanism M1 having the above configuration will be described.
When the main shaft 2 is rotated by driving the sewing machine motor 2a to rotate the eccentric cam 3, the tip of the connection link 4 is in a direction substantially perpendicular to the axis of the main shaft 2 (the series direction D2 of the third link 20 and the fourth link 22). Oscillating in the direction D3) transverse to the oscillating shaft, and the oscillating shaft holder 5 connected to the connecting link 4 also oscillates in the same direction. Since the swing shaft holder 5 swings, the swing shaft 6 also swings. Therefore, one end of the first link 8 serves as a swing fulcrum, and the other end of the first link 8 serves as the swing shaft 6. Oscillates in a direction substantially perpendicular to the axis (direction D3 transverse to the series direction D2 of the third link 20 and the fourth link 22). As the other end portion of the first link 8 swings, the other end portion of the second link 11 swings in the series direction D2 of the third link 20 and the fourth link 22, and the other end portion of the second link 11 The connected third link 20 and fourth link 22 swing in the series direction (vertical direction) D2. As the third link 20 and the fourth link 22 swing, the intermediate presser bar 28 connected to the fourth link 22 moves downward along the vertical direction D1, so the intermediate presser 29 moves in the vertical direction. Further, since the sewing needle 108 moves up and down by the rotation of the main shaft 2, the intermediate presser 29 moves up and down so as to interlock with the vertical movement of the sewing needle 108.
In the following description, the sewing needle 108 and the intermediate presser 29 are positioned at the top dead center when the angle of the main shaft 2 is 0 °, and the sewing needle 108 and the intermediate presser 29 are lowered when the angle of the main shaft 2 is 180 °. It shall be located at the dead point.

(Adjusting the bottom dead center height of the intermediate presser with the intermediate presser)
Next, the operation of adjusting the height of the intermediate presser 29 by the intermediate presser height adjusting mechanism M4 of the intermediate presser device 1 having the above configuration will be described.
The drive of the intermediate presser motor 42 is transmitted to the movable shaft 39 via the bevel gear 41 and the bearing 40, and the movable shaft 39 starts to rotate. The eccentric cam 38 is also rotated by the rotation of the movable shaft 39, and the moving link 36 is in a direction substantially orthogonal to the axis of the movable shaft 39 (a direction crossing the series direction D2 of the third link 20 and the fourth link 22). Swing to D3). As the moving link 36 swings, the guide member 34 swings in a direction D3 that intersects the series direction D2 of the third link 20 and the fourth link 22.
At this time, as shown in FIGS. 6A and 6B, the stepped screw 23 (square piece 33) of the connecting portion P of the third link 20 and the fourth link 22 connected by the elongated hole 34a of the guide member 34. Since the threaded portion of the third link 20 and the fourth link 22 is restricted from moving in the direction D3 across the series direction D2 by the long hole 34a (see FIGS. 5 and 6A). The place where the force transmitted by the swing is released is eliminated, and the step screw 23 (square piece 33) moves upward along the long hole 34a, and the movement following the guide member 34 of the step screw 23 (square piece 33). Accordingly, the angle formed between the third link 20 and the fourth link 22 that are connected in series is changed, and the intermediate presser link member 24 has a substantially square shape (see FIG. 6B). . When the intermediate presser link member 24 has a substantially square shape, the intermediate presser 29 moves upward along the vertical direction D1. Thereby, the bottom dead center height of the intermediate presser 29 from the needle plate 110 of the intermediate presser 29 can be adjusted.

(Sewing machine control system: control device)
Further, as shown in FIG. 7, the sewing machine 100 includes a control device 1000 as an operation control unit for controlling the operation of each unit and each member described above. The control device 1000 stores a program memory 70 in which a sewing program 70a, a frame position teaching program 70b, and an intermediate presser height teaching program 70c are stored, a sewing pattern data 71a, and various setting information (not shown). A data memory 71 as means and a CPU 73 for executing each program 70a, 70b, 70c in the program memory 70 are provided.

  The CPU 73 is connected to the operation panel 74 via the interface 74a. The operation panel 74 includes a display unit 74b that displays various screens and input buttons, and a touch sensor 74c that is provided on the surface of the display unit 74b and detects a contact position thereof, and functions as an input / output unit for various types of information. To do. Any of the input buttons and input switches used on the operation panel 74 are displayed on the display unit 74b and function in the same manner as push-down buttons and switches when an input is detected by the touch sensor 74c.

The CPU 73 is connected to a sewing machine motor driving circuit 75b that drives the sewing machine motor 2a via the interface 75, and controls the rotation of the sewing machine motor 2a. Further, the increase / decrease in torque can be adjusted by controlling the energization current of the sewing machine motor 2a through the sewing machine motor drive circuit 75b.
The sewing machine motor 2a is provided with an encoder 2b. In the sewing machine motor driving circuit 75b for driving the sewing machine motor 2a, a Z-phase signal output from the encoder 2b for each rotation of the sewing machine motor 2a is transmitted via the interface 75. Input to the CPU 73, and the CPU 73 can recognize the origin (0 ° position) in one rotation of the main shaft 2 by this signal. Further, an A-phase signal output from the encoder 2b every 1 ° in the rotation angle of the sewing machine motor 2a is input to the CPU 73 via the interface 75, and the number of pulses of the A-phase signal based on the Z-phase signal described above. The CPU 73 can recognize the current rotation angle of the main shaft 2.
For example, a servo motor can be applied to the sewing machine motor 2a.

  The CPU 73 also has an X-axis motor driving circuit 76b and a Y-axis motor for driving an X-axis motor 76a and a Y-axis motor 77a provided in the holding frame 111 that holds the fabric to be sewn via the interface 76 and the interface 77, respectively. A drive circuit 77b is connected to control the operation of the holding frame 111 in the X-axis direction and the Y-axis direction.

The CPU 73 is connected to an intermediate presser motor drive circuit 78b for driving an intermediate presser motor 42 that can move the intermediate presser 29 up and down separately from the vertical movement by the sewing machine motor 2a via the interface 78. Control the behavior. Further, the increase / decrease in torque can be adjusted by controlling the energization current of the intermediate presser motor 42 through the intermediate presser motor drive circuit 78b.
The output shaft of the intermediate presser motor 42 is provided with an encoder 81 as a motor shaft angle detecting means. In the intermediate presser motor drive circuit 79b for driving the intermediate presser motor 42, the encoder 81 is connected to one of the intermediate presser motors 42. A Z-phase signal output for each rotation is input to the CPU 73 via the interface 75, and the CPU 73 can recognize the origin (0 ° position) in one rotation of the output shaft of the intermediate presser motor 42 by this signal. Further, an A-phase signal output from the encoder 81 every 1 ° in the rotation angle of the intermediate presser motor 42 is input to the CPU 73 via the interface 78, and the pulse of the A-phase signal is based on the Z-phase signal described above. Counting the number, the CPU 73 can recognize the current rotation angle of the output shaft of the intermediate press motor.

Further, the CPU 73 is connected to a cloth presser motor driving circuit 79b for driving a cloth presser motor 79a that moves the cloth presser (not shown) up and down via the interface 79, and controls the vertical movement operation of the cloth presser.
The cloth presser motor 79a is connected to a cloth presser vertical movement mechanism and a thread trimming device (not shown) via a cam mechanism, and the cloth presser moves up and down in a part of a 360 ° rotation range. The other section is assigned to drive the thread trimming operation of the thread trimming device. Therefore, by controlling the cloth presser motor 79a, not only the vertical movement operation of the cloth presser but also the thread trimming operation can be controlled.
For example, a stepping motor can be applied to the X-axis motor 76a, the Y-axis motor 77a, the intermediate presser motor 42, and the cloth presser motor 79a.

  Further, the CPU 73 is connected to a solenoid drive circuit 82b that drives a thread tension solenoid 82a that is a drive source of a thread tension device (not shown) that applies a thread tension to the sewing thread via the interface 82, and increases or decreases the thread tension. Control.

As shown in FIG. 8, the sewing pattern data 71a stored in the data memory 71 includes an X-direction movement amount and a Y-direction movement when the holding frame 111 is moved in order to execute a hand movement pattern for sewing. A sewing command indicating the amount data (stitch data indicating the needle entry position), an end command, an intermediate presser height command that determines the bottom dead center height of the intermediate presser 29, a thread tension command, a thread trimming command, and an end command are combined. ing.
Then, various commands are executed in accordance with the arrangement order, whereby sewing with an arbitrary pattern (pattern) is executed.
In the sewing pattern data shown in FIG. 8, in the “sewing” command, the X-direction movement amount and Y-direction movement amount data (parameters) when moving the holding frame 111 are set to the first set value and the second set value. These are recorded, and the rotational drive amounts of the X-axis motor 76a and the Y-axis motor 77a are determined by these.
In the “intermediate presser height” command, the bottom dead center height of the intermediate presser 29 determined by the intermediate presser motor 42 is recorded as the first set value, and the rotational drive amount of the intermediate presser motor 42 is determined thereby. The
In the “thread tension” command, the thread tension to be applied to the sewing thread by the thread tension device is recorded as the first set value, and the output of the thread tension solenoid 82a is determined thereby.
“Thread trimming” is a command for operating a thread trimming device (not shown), and “End” is a command for driving the cloth pressing motor 79a of the sewing machine 100 to release the cloth.
In addition, the notation in the numerical data of the X movement amount, the Y movement amount, and the intermediate presser height in FIG. 8 is 10 times, for example, “15” indicates “1.5 mm”.
Further, although not shown, the sewing pattern data 71a can also record the hardness of the sewing product acquired by executing an intermediate presser height teaching program 70c described later.

(Sewing process by sewing program)
The sewing program 70a stored in the program memory 70 reads out each command of the sewing pattern data 71a in order, specifies the control target according to the command, and based on the set numerical value in the command, the sewing machine motor 2a, the X axis This program controls the operation of the motor 76a, the Y-axis motor 77a, the intermediate presser motor 42, and the thread tensioner solenoid 82a, and executes sewing based on the sewing pattern data 71a.
For example, in the case of the sewing pattern data 71a shown in FIG. 8, the “intermediate presser height”, “thread tension”, and “sewing” commands, which are data related to the first stitch in the sewing pattern data, are input by the pedal R and The set values are read, and based on these, the intermediate presser motor 42, the thread tensioner solenoid 82a, the X-axis motor 76a, and the Y-axis motor 77a are driven with an operation amount corresponding to each set value. Further, the driving of the sewing machine motor 2a is started by reading the first “sewing” command.
After the start of driving of the sewing machine motor 2a, the main shaft angle is monitored by the count of the encoder 2b, and the command of each needle in the sewing pattern data 71a is read at a predetermined main shaft angle, and a predetermined value determined for each command. The operation of the controlled object is executed at the main shaft angle.

The rotational speed at the time of sewing of the sewing machine motor 2a and the torque value at the time of rotational driving are recorded in the data memory 71 as set values set from the operation panel 74, and the drive control of the sewing machine motor 2a is performed accordingly. To be done.
Further, regarding the positioning control of the holding frame 111 of the X-axis motor 76a and the Y-axis motor 77a, the operation period from the start to the stop of the frame movement is determined by the spindle angle. During the operation period, a table indicating the correspondence between the operation amount and the operation period is recorded in advance in the data memory 71 for each of the X-axis motor 76a and the Y-axis motor 77a. When the movement amount of the “sewing” command is read from the data 71a, the operation period is read with reference to the corresponding table, and the control of the motors 76a and 77a is executed by the operation start and end timings by the encoder 2b.

(Processing by frame position teaching program)
The frame position teaching program 70b is for confirming the operation based on the “sewing” and “intermediate presser height” commands of each needle in the sewing pattern data 71a and correcting the set value. In teaching based on the frame position teaching program 70b, the sewing motor 2a is not driven, and commands for each needle of the sewing pattern data 71a are sent to a forward key and a backward key (not shown) provided on the operation panel 74. Reproduce by executing one stitch at a time in the sewing order or reverse order according to the input. At this time, if the setting value needs to be corrected by the reproduction operation for each stitch, the operator selects the type of command through the operation panel 74 and corrects the setting value using the increase / decrease key. When there is such an input, the CPU 73 executes an operation control for performing a reproduction operation with a new set value for the corrected command. When confirmation is input, the sewing pattern data 71a is updated according to the correction content.
If the sewing pattern data 71a includes commands other than “sewing” and “intermediate presser height”, they can be reproduced and corrected in the same manner.

(Processing by intermediate presser height teaching program)
The intermediate presser height teaching program 70c is used to set the command and set value of the “intermediate presser height” and record the hardness of the sewing product for the sewing pattern data 71a. It is possible to set the intermediate presser height even when the above-described frame position teaching program 70b is executed. In this case, the setting is performed by numerically inputting the intermediate presser height determined by the operator. .
On the other hand, when the intermediate presser height teaching program 70c is executed, the “cloth presser” is determined from the cloth thickness of the sewing product actually measured at each needle drop position in the process in which the frame moving operation is reproduced according to the sewing pattern data 71a by the process described later. The "height" command is obtained and automatically set in the sewing pattern data 71a by the sewing machine.

Control performed by the CPU 73 by the intermediate presser height teaching program 70c will be described in detail with reference to FIGS.
FIG. 9 is a diagram (upper diagram) showing a change in the height of the intermediate presser 29 which reproduces the vertical movement while simulating the vertical movement at the time of sewing only by the intermediate presser motor 42 without driving the sewing machine motor 2 and its It is the diagram (lower figure) which showed the torque change of the intermediate pressing motor 42 at the time. In the diagram showing the torque change in FIG. 9, the upper side shows the magnitude of torque in the rotational direction that moves the intermediate retainer 29 upward from the zero position, and the lower side shows torque in the rotational direction that moves the intermediate retainer 29 downward. Indicates the size.
10A is the point a in FIG. 9, FIG. 10B is the point bc section in FIG. 9, and FIG. 10C is the intermediate presser height at each intermediate presser height at the point c in FIG. It is the schematic diagram which showed the operation state of the thickness adjustment mechanism M4. In FIG. 10, for the sake of convenience, the bending direction of the links 20 and 22 and the arrangement of the intermediate presser motor 42 are reversed left and right for the sake of convenience, but this does not affect the following explanation of the principle.

During intermediate presser height teaching based on the intermediate presser height teaching program 70c, the X-axis motor 76a and the Y-axis motor 77a are driven on the basis of the sewing pattern data 71a while the sewing machine motor 2a is stopped. Check operation control that reproduces the relative positioning operation of each workpiece to be sewn, and one reciprocation consisting of lowering and raising of the intermediate presser 29 for each reproduction operation of the holding frame 111 for one stitch based on the sewing pattern data 71a. Operation control for performing a vertical movement operation is performed. Since the confirmation operation control is performed by stopping the sewing machine motor 2a, the vertical movement of the intermediate presser 29 is executed using the intermediate presser motor 42 as a drive source.
In the lowering operation for each stitch of the intermediate presser 29, variable height control is performed in which the press when the intermediate presser 29 is in contact with the workpiece is reduced by the torque control of the intermediate presser motor 42 than when it is raised. When the stop of the lowering of the intermediate presser 29 by the encoder 81 is detected during execution of the variable height control, the thickness of the sewing product is obtained from the height of the intermediate presser 29 when the stop occurs. A thickness acquisition process is performed.
Further, when the thickness of the sewing product is obtained in the height variable control, the thickness for recording the acquired thickness of the sewing product in association with the sewing pattern data 71a in the order of the number of stitches. A recording process is performed.
In addition, when the thickness of the sewing product is obtained in the height variable control, pressing control for gradually changing the torque value of the intermediate presser motor 42 so that the contact pressure to the sewing product by the intermediate presser 29 increases. When the lowering of the intermediate presser 29 is detected by the encoder 81 during execution of the press control, a hardness acquisition process is performed to record the hardness of the sewing product obtained from the torque value of the intermediate presser motor 42 at the time of the lowering. .
Thus, by executing the intermediate presser height teaching program 70c, the CPU 73 causes the sewing control means, the intermediate presser height control means, the thickness acquisition processing means, the intermediate presser pressure control means, the hardness acquisition processing means, the thickness. It will function as a recording means.

(Medium presser height teaching program: Confirmation operation control)
Each control and each process will be described in more detail.
In the reproduction operation based on the sewing pattern data 71a, the CPU 73 does not drive the sewing machine motor 2a in a state where the sewing product is set on the holding frame 111, and does not drive the sewing machine 2a. The holding frame 111 is positioned one stitch at a time according to the sewing pattern data 71a.

(Medium presser height teaching program: Height variable control)
In the variable height control, as shown in FIG. 10, the main shaft angle of the sewing machine motor 2a is fixed at the upper stop position near the top dead center (the main shaft stop position at the end of normal sewing), and the holding frame 111 is moved. The lowering operation of the intermediate presser 29 by the intermediate presser motor 42 is started at a predetermined elapsed timing after the driving of the X-axis and Y-axis motors 76a and 77a to be started.
The intermediate presser motor 42 starts to descend from the position where the intermediate presser 29 is pulled up most within the movable range (the state shown in FIG. 9A and FIG. 10A) as the initial position in every vertical movement, and has a thickness. The vertical movement is performed so that the workpiece can be touched from above.

  When the intermediate presser 29 is lowered, it is desirable that the drive torque T2 of the intermediate presser motor 42 be sufficiently smaller than the drive torque T0 when the intermediate presser 29 is raised as shown in FIG. As a result, when it comes into contact with the sewing product when it is lowered, the intermediate presser 29 cannot be lowered further by the driving torque of the intermediate presser motor 42, and the intermediate presser 29 is stopped on the upper surface of the sewing product without excessive pressurization. be able to.

As described above, the intermediate presser 29 is constantly pressed downward by the pressing spring 30.
That is, as shown in FIG. 11, since the intermediate presser 29 is always pressed downward by the pressing spring 30 with the pressing force indicated by the arrow Y1, the spring thickness is increased so that the links 20 and 22 in the bent state extend straight. As a result, the link member 20 receives the torque indicated by the arrow Y2, the square piece 33 is pulled in the direction of the arrow Y3, the turning force is applied to the guide member 34 in the direction of the arrow Y4, and the moving link 36 is indicated by the arrow. Pulled in the direction of Y5, the load shaft T1 is applied to the output shaft of the intermediate presser motor 42 via the eccentric cam 38 in the direction of arrow Y6.
On the other hand, since the intermediate presser motor 42 also outputs a driving torque T2 having a magnitude smaller than that when the intermediate presser 29 is lowered in the direction in which the intermediate presser 29 is lowered, the pressing force applied to the sewing product when the intermediate presser 29 is lowered is a pressing spring. 30 is the sum of the pressing force and the pressing force resulting from the driving torque in the downward direction of the intermediate pressing motor 42, but the respective pressing forces are set sufficiently small so that excessive pressing does not occur. Yes.

  When the intermediate presser 29 moves downward and comes into contact with the thick step portion of the sewing product (the state shown in FIG. 10B), the lowering stops halfway. At this time, since the torque of the intermediate presser motor 42 when the intermediate presser 29 is lowered is smaller than the driving torque when it is raised as described above, the intermediate presser 29 stops the lowering without pressing the workpiece. be able to. Then, the CPU 73 can detect the arrival (downward stop) of the sewing product by switching from the rotation state of the shaft angle of the intermediate presser motor 42 to the stop state (angle change) through the encoder 81.

(Medium presser height teaching program: Thickness acquisition processing)
The thickness acquisition process is executed when the lowering stop of the intermediate presser 29 is detected in the variable height control performed for each needle reproduction operation.
The CPU 73 obtains the height from the intermediate presser 29 to the needle plate (= thickness of the sewing product) from the detection shaft angle of the encoder 81 in the descending stop state. For example, the shaft angle of the intermediate presser motor 29 and the height of the intermediate presser 29 are calculated in advance from design values of the respective members. Further, a correspondence table of shaft angle and intermediate presser height created by prior measurement or the like may be prepared in the data memory 71 and acquired by referring to this.

(Medium presser height teaching program: thickness recording process)
In the thickness recording process, the actually measured thickness of the sewing object is recorded with respect to the sewing pattern data 71a. Therefore, when the intermediate presser height teaching is started, the intermediate presser height already recorded in the sewing pattern data 71a is recorded. All of the command and its set value data are deleted in advance.
Then, when the thickness of the sewing product for each stitch is obtained by the thickness acquisition process, the CPU 73 compares the thickness of the sewing product at the previous needle drop position with a predetermined constant A. Only when the above difference occurs, the intermediate presser height command and the thickness of the sewing product obtained as the set value are newly recorded for the corresponding number of stitches in the sewing pattern data 71a.
Here, the value of the constant A is a threshold that can be set by the operation panel 74 and is stored in the data memory 71 by the setting.
Further, when the detected thickness of the sewing product is recorded in the sewing pattern data 71a, correction by adding the correction value α is performed. The correction value α is a numerical value that can be arbitrarily set by the operation panel 74 and is recorded in the data memory 71. In this example, the correction value is a value to be added, but a numerical value that performs addition, subtraction, multiplication, and division may be used as the correction value.

(Medium presser height teaching program: Press control)
When the lowering of the intermediate presser 29 is stopped, the CPU 73 changes the torque of the intermediate presser motor 42 so as to gradually increase the downward pressing force by the intermediate presser 29. That is, control is performed so as to gradually increase the torque to the lower side of the intermediate presser motor 42 that is stopped on the upper surface of the workpiece (from FIG. 12A to FIG. 12B).

When the pressing force of the sewing product exceeds a certain pressing force, the intermediate presser 29 moves downward while denting the sewing product (the state shown in FIG. 9 c and FIG. 10C). Such pressing control is continued until the encoder 81 detects a change in which the shaft angle of the intermediate presser motor 29 is lowered.
The variation rate of the torque of the intermediate presser motor 42 in the press control can be set from the operation panel 74, and the set value is stored in the data memory 71. Therefore, in the press control, the torque of the intermediate presser motor 42 is changed according to the change rate stored in the data memory 71. The smaller the variation rate, the more accurately the hardness of the sewing product can be detected.
Similarly, the lowering amount of the intermediate presser 29 for determining that a dent has occurred in the workpiece can be set from the operation panel 74, and the set value is stored in the data memory 71. It is desirable that the set value of the lowering amount be in a range that does not damage the sewing product.
Further, as shown in FIG. 11, the guide member 34 to which the turning motion is given by the intermediate pressing motor 42 is connected to the second link 11 via the third link 20, and the second link 11 is The intermediate portion is supported by the first link 8, and the other end is biased upward by the tension spring 16 and is in pressure contact with the regulating member 19 (the tension spring 16 is actually connected to the second member via the mounting member 13. Although it is connected to the link 11, the structure is simplified for easy understanding of the description, and there is no functional difference).
In such a structure, when the driving torque in the lowering direction of the intermediate presser motor 42 is gradually increased by pressing control, if the material to be sewn is an excessively hard material, the tension spring 16 bends before the thickness changes, and the second link 11 may be separated from the restricting member 19 so that the hardness cannot be detected. Therefore, it is desirable that the driving torque of the intermediate presser motor 42 in the pressure control is set to an upper limit within a range where the left end portion of the second link 11 does not separate from the regulating member 19 against the tension spring 16.

(Medium presser height teaching program: Hardness acquisition processing)
In the press control, when the encoder 81 detects the lowering of the intermediate presser 29, the CPU 73 proceeds to a hardness acquisition process. In the hardness acquisition process, the torque value of the intermediate presser motor 42 at the time when the intermediate presser 29 is lowered is stored, and the hardness of the workpiece is acquired from the torque value. In other words, the torque value of the intermediate presser motor 42 has a certain correspondence relationship with the pressing force applied to the sewing product by the intermediate presser 29, and the pressing force applied to the sewing product by the intermediate presser 29 that causes a dent in the sewing product and the applied pressure. Since there is a certain correspondence with the hardness of the sewing product, a correspondence table between the torque value created by prior measurement and the hardness of the sewing product is prepared in the data memory 71, and the sewing is performed by referring to this table. The hardness of an object can be acquired.
Then, the hardness of the sewing product obtained by the hardness acquisition process is stored in the sewing pattern data 71a. In addition, about the hardness of the to-be-sewn material recorded, not only the case where actual hardness is digitized and recorded, but the numerical information which can specify hardness should just be recorded. For example, the torque value itself of the intermediate pressing motor 42 at the time when the lowering occurs may be recorded.
In addition, about press control and hardness acquisition processing, you may carry out for every needle | hook, you may carry out only about the number of needle | hooks at the time of recording of intermediate presser height, or about one sewing thing It can be done only once.

In the hardness acquisition process, when the hardness of the sewing product is obtained, the CPU 73 rewrites the value obtained by multiplying the set thread tension of the thread tension command recorded in the sewing pattern data 71a by a coefficient and correcting it. Process. That is, when the sewing product becomes hard, the thread tension needs to be set high, so that the thread tension is increased or decreased according to the hardness of the sewing object. The relationship between the hardness of the sewing product and the coefficient to be multiplied by the thread tension is recorded in a correspondence table prepared in advance in the data memory 71, and is obtained by referring to this. When the thread tension solenoid 82a is controlled without rewriting the thread tension setting of the sewing pattern data 71a, for example, the coefficient is obtained from the hardness of the workpiece recorded in the sewing pattern data 71a when actually sewing is performed. In addition, correction may be performed.
Similarly, when the hardness of the sewing product is obtained, the CPU 73 performs a process for correcting the operation period of the X-axis motor 76a and the Y-axis motor 77a for positioning the sewing product. In other words, when the work to be sewn is hard, the operation of the sewing needle is slowed down and the operation period needs to be set short. Therefore, the correction values for the main shaft angles at the start and end of the motors 76a and 77a are corrected. Correction to increase or decrease is performed. The relationship between the hardness of the sewing product and the correction value is recorded in a correspondence table prepared in advance in the data memory 71, and is obtained by referring to this. The correction value may be recorded in the sewing pattern data 71a, or when actually sewing, the correction value is obtained from the hardness of the sewing product recorded in the sewing pattern data 71a, and each motor 76a, 77a is obtained. Correction may be performed when determining the drive timing.
Similarly, when the hardness of the sewing product is obtained, the CPU 73 performs a correction process by multiplying the set torque of the sewing machine motor 2a by a coefficient. That is, when the workpiece becomes hard, it is necessary to increase the penetrating force of the sewing needle, so that the torque value of the sewing machine motor 2a is increased or decreased by the coefficient. The relationship between the hardness of the workpiece and the coefficient is recorded in advance in a correspondence table prepared in the data memory 71, and is obtained by referring to this. The above coefficient may be recorded in the sewing pattern data 71a, or when actually sewing, the coefficient is obtained from the hardness of the sewing object recorded in the sewing pattern data 71a, and the torque when the sewing machine motor 2a rotates. Correction may be performed.

  Further, when the press control is performed (when the press control is not performed for each needle, after the descent stop by the variable height control), the intermediate presser motor 42 is in the middle presser motor 42 before the start of the next lowering operation. Is moved up to the uppermost position (points d and e in FIG. 9). For example, the torque of the intermediate presser motor 42 in the upward movement is controlled so that it is sufficiently large with respect to the load torque T1 in the pressing spring 30 as in the case of driving when changing the bottom dead center during normal sewing. Is done.

(Explanation of operation in teaching of the middle presser height of the sewing machine)
Control and processing performed by the CPU 73 by executing the intermediate presser height teaching program 70c will be described based on the flowchart shown in FIG.
The start of the intermediate presser height teaching can be input from the operation panel 74. Upon receiving the input, as shown in FIG. 13, the CPU 73 first starts reading the sewing pattern data 71a (step S1). Then, all the intermediate presser height commands and the set value data in the sewing pattern data 71a are deleted (step S2).
Then, when the sewing product is set in the holding frame 111 and an instruction to lower the holding frame 111 is input from the pedal R, the cloth holding motor 79a is driven to lower the holding frame 111 (step S3).

Next, it is determined whether or not there is an input for starting sewing from the pedal R (step S4). When there is an input, the cloth presser motor 79a is driven to lower the holding frame 111. At this time, the CPU 74 sets 0 as the value of the cloth thickness as an initial value (step S5).
Then, cloth thickness detection is started (step S6). The details of the cloth thickness detection will be described in detail with reference to the flowchart of FIG.

In the cloth thickness detection, first, the sewing motor 2a is not driven, and the positioning reproduction by the X-axis motor 76a and the Y-axis motor 77a is performed in accordance with the X-direction movement amount and Y-direction movement amount data in the current stitch number of the sewing pattern data 71a. The operation is started (step S31: confirmation operation control).
Next, the current of the intermediate presser motor 42 is reduced to a low current and the torque is suppressed to start the lowering of the intermediate presser 29 (step S32: height variable control).
When the thick step is sent to the seam forming position where the intermediate presser 29 is lowered, the intermediate presser stops the lowering operation halfway at the thickness position of the step.
Then, the output of the encoder 81 during the lowering of the intermediate presser 29 is monitored, and it is determined whether or not a change in the rotation state of the output shaft of the intermediate presser motor 42 (here, the rotational state → the stopped state) has occurred (step S33). .
When a change in the rotation state of the intermediate presser motor 42 is detected in this way, the thickness of the sewing product is calculated from the detection angle of the encoder 81 at that time (step S34: thickness acquisition process).

When the cloth thickness is obtained, the contact pressure of the intermediate presser 29 with respect to the workpiece is increased by the set increase ratio by the torque control of the intermediate presser motor 42 (step S35: press control). Then, it is determined whether or not the detection angle of the encoder 81 shows a downward change (step S36). When there is no downward change, the energization current value of the intermediate presser motor 42 is within the allowable range in the rotational direction in which the intermediate presser 29 is lowered (for example, the left end portion of the second link 11 described above is a regulating member). It is determined whether or not the current value is such that it is not separated from the current value 19 (step S37). If not, the process returns to step S35, and the current value to the intermediate presser motor 42 is increased again by the set increase ratio.
On the other hand, when the encoder 81 detects a downward change (step S36: YES) or when the energizing current value of the intermediate presser motor 42 reaches the maximum current value (step S37: YES), the hardness of the sewing product is set. Calculate (step S38: hardness acquisition process). If no change in the lowering of the intermediate presser 29 is detected even when the energizing current of the intermediate presser motor 42 is maximized, the hardness is determined to be greater than the measurable range.
Then, the intermediate presser 29 is returned to the uppermost position by driving the intermediate presser motor 42, whereby the reproduction operation for one stitch is completed. The torque of the intermediate presser motor 42 at the time of ascent is controlled to a high value as in the case where normal sewing is performed.

When the cloth thickness is detected, as shown in FIG. 13, the cloth thickness obtained in step S34 is compared with the value set as the current cloth thickness (step S7).
If the difference between the detected cloth thickness and the current cloth thickness is equal to or less than a preset constant A as a result of the comparison, the detected cloth thickness is not recorded as the cloth thickness corresponding to the number of stitches in the sewing pattern data 71a. The number is advanced by 1 (step S11), the process is returned to step S6, and the cloth thickness is detected at the next number of stitches.
In step S7, when the difference between the detected cloth thickness and the current cloth thickness is larger than a preset constant A, it is considered that the cloth thickness has changed from the previous needle drop position, The current fabric thickness is updated to the detected fabric thickness value (step S8).
Then, a process is performed in which the current fabric thickness (= detected fabric thickness) is written for the corresponding number of stitches in the sewing pattern data 71a (step S9: thickness recording process). That is, an intermediate presser height command is generated before the sewing command for the number of stitches, and a value corrected by adding the above-described correction value α to the current cloth thickness is recorded.
At the same time, the data of the hardness of the sewing object at the current number of stitches is written into the sewing pattern data 71a.
Then, it is determined whether or not the current number of stitches is the last stitch of the sewing pattern data 71a (step S10). If it is not the last stitch, the number of stitches is incremented by one, and the process returns to step S6. In this case, the intermediate presser height teaching is finished.

(Effect of embodiment)
The electronic cycle sewing machine 100 avoids pressing when the intermediate presser 29 that is lowered by the height variable control contacts the sewing product, and obtains the thickness of the sewing product by the thickness acquisition process. It is possible to detect the thickness of the cloth while preventing the occurrence of scratches due to the damage and protecting the cloth.
Further, since the cloth thickness detection is performed in synchronization with the positioning operation of the sewing object for each needle that is executed according to the sewing pattern data, an artificial intermediate presser height is obtained by repeating visual work and trial and error. Unlike simple setting work, it is possible to easily and quickly acquire sewing pattern data in consideration of the thickness of the workpiece.
In addition, since the positioning operation of the sewing product for each stitch executed in accordance with the sewing pattern data is performed without driving the sewing machine motor 2a, the sewing product is not wasted for data creation.

  Further, in the electronic cycle sewing machine 100, since the cloth thickness is detected by the control of the intermediate presser motor 42 using the encoder 81, the thickness of the sewing object is not used without using a cloth thickness detector for detecting the contact position or the distance. Therefore, it is possible to improve productivity by reducing the number of parts. Furthermore, with the above configuration, it is not necessary to arrange the needle bar around the needle bar, and it is possible to secure a wide working space around the needle bar and mount other mechanisms and members around the needle bar of the sewing machine. Does not hinder.

Further, since the thickness of the obtained sewing product is recorded in the sewing pattern data 71a only when there is a change of a predetermined value or more as compared with the thickness of the sewing product acquired one stitch before, the sewing pattern It is possible to reduce the data amount of the data 71a and reduce the processing load of the processing means associated with the execution of the sewing pattern data.
Further, since the thickness of the sewing product recorded in the sewing pattern data 71a can be corrected, the correction is performed individually in consideration of changes in various conditions that affect the thickness detection of the sewing product. Thereby, it becomes possible to obtain | require the thickness of to-be-sewn material more correctly.

Further, in the electronic cycle sewing machine 100, after the thickness of the sewing product is detected, the contact pressure by the intermediate presser 29 is increased, and the torque value of the intermediate presser motor 42 when the sewing product is recessed and the intermediate presser 29 is lowered. Therefore, the hardness of the sewing product can be detected without using a dedicated detection device such as a pressure sensor.
Further, since the thread tension, the positioning operation period of the sewing product, and the torque of the sewing machine motor 2a are corrected according to the detected hardness of the sewing product, proper sewing is performed according to the hardness of the sewing product. Therefore, it is possible to improve the sewing quality. In addition, since it is not necessary to provide dedicated hardness detection means around the needle bar, as in the case of thickness detection, it is possible to secure a wide space around the needle bar as a work space and to use the needle bar of the sewing machine. It does not hinder the mounting of other mechanisms and members around.

(Other)
The thickness and hardness of the sewing product were detected with the sewing machine motor 2 a stopped. However, the sewing machine motor 2 a was driven to use the sewing machine motor 2 a as a vertical movement drive source for the intermediate presser 29. You may detect the thickness and hardness of a to-be-sewn material in a state.
In this case, during the height variable control, the intermediate presser 29 is lowered by the sewing machine motor 2a, so that the output shaft of the intermediate presser motor 42 is not changed so as to change downward, and a constant angle is set. Maintain a standstill to maintain. The torque value is controlled so that an upward driving torque is output so as to balance the pressing force of the pressing spring 30 so that the output shaft of the intermediate pressing motor 42 does not rotate.
Further, whether or not the intermediate presser 29 is in contact with the workpiece is determined by the encoder 80 detecting a change from the stop state to the rotation state of the output shaft of the intermediate presser motor 42.
In calculating the height of the intermediate presser 29 (the thickness of the sewing product), not only the detection angle of the intermediate presser motor 42 but also the spindle angle when the intermediate presser 29 contacts the sewing product is taken into consideration. There is a need to.
Further, when the hardness is detected, immediately after the contact with the sewing product is detected, the intermediate presser motor 42 maintains the constant angle while the sewing machine motor 2a is rotating. Control is performed to gradually increase the drive torque. At this time, while the torque is insufficient, the intermediate presser motor 42 cannot maintain the command angle, and the output shaft continues to rotate. However, if the torque exceeds the hardness of the sewing product, the intermediate presser 29 Following the intermediate presser motor 42, the lowering occurs and the rotation of the output shaft stops. The torque value when the rotation is stopped is recorded, and the hardness of the sewing product is calculated from the torque value.
Considering the above points, it is possible to detect the thickness and hardness of the sewing object even when the sewing machine motor 2a is driven.
In addition to the teaching, the thickness and hardness of the workpiece to be sewn may be detected in real time while the sewing motor 2a is driven to perform actual sewing.

It is a perspective view which shows the sewing machine which concerns on this invention. It is an expansion perspective view which shows the holding frame of a sewing machine, and the vicinity of intermediate pressing. It is a side view which shows the intermediate press apparatus of a sewing machine. It is a disassembled perspective view of an intermediate pressing device. It is a disassembled perspective view of an intermediate pressing device. It is explanatory drawing regarding the height adjustment of the intermediate presser of the intermediate press device, FIG. 6 (a) shows a case where the bottom dead center is adjusted downward, and FIG. 6 (b) abuts the bottom dead center for adjustment. Show the case. It is a block diagram which shows the control apparatus of the sewing machine which concerns on this invention. It is explanatory drawing which shows the data structure of sewing pattern data. FIG. 7 is a diagram showing a change in height of the intermediate presser that simulates a vertical motion during sewing by the intermediate presser motor and reproduces the vertical motion, and a diagram showing a torque change of the intermediate presser motor at that time. 10A is the point a in FIG. 9, FIG. 10B is the point bc section in FIG. 9, and FIG. 10C is the intermediate presser height adjustment at each intermediate presser height at the point c in FIG. It is the schematic diagram which showed the operation state of the mechanism. It is a schematic diagram for demonstrating the torque load which the press spring of an intermediate presser height adjustment mechanism brings to an intermediate presser motor. FIG. 12A is an explanatory view showing a state of a force applied to the intermediate presser that is being lowered in the variable height control, and FIG. 12B is a diagram when the intermediate presser is in contact with the sewing product in the variable height control. It is explanatory drawing which shows the state of the force to apply. It is a flowchart which shows the whole process in the intermediate presser height teaching based on this invention. It is a flowchart which shows the process in connection with the cloth thickness detection in the intermediate presser height teaching based on this invention.

Explanation of symbols

1 Intermediate presser 2 Spindle 2a Sewing machine motor 2b Encoder (Spindle angle detection means)
16 Tension spring 20 Third link 22 Fourth link 29 Intermediate presser 30 Pressing spring 33 Square piece (motion transmission member)
34 Guide member (motion transmission member)
42 Intermediate presser motor 70a Sewing program 70b Intermediate presser height control program 71a Sewing pattern data 73 CPU (sewing control means, intermediate presser height control means, thickness acquisition processing means, thickness recording means, intermediate presser pressure control means, hard Acquisition processing means)
74 Operation panel (section setting means)
76a X-axis motor (positioning motor)
77a Y-axis motor (positioning motor)
81 Encoder (Motor shaft angle detection means)
DESCRIPTION OF SYMBOLS 100 Electronic cycle sewing machine 110 Needle plate 1000 Control apparatus M1 Middle presser vertical movement mechanism M2 Energizing mechanism M3 Middle presser retraction mechanism M4 Middle presser height adjustment mechanism

Claims (3)

A needle up-and-down moving mechanism for moving the sewing needle up and down by a sewing motor, and a spindle angle detecting means for detecting an angle of a spindle driven to rotate by the sewing machine motor;
An intermediate presser that prevents the sewing product from lifting when sewing,
An intermediate presser vertical movement mechanism that obtains power from the sewing machine motor and moves the intermediate presser up and down in synchronization with the vertical movement of the sewing needle;
In a sewing machine comprising an intermediate presser height adjusting mechanism that moves the bottom dead center height of the intermediate presser of the intermediate presser vertical movement mechanism up and down by an intermediate presser motor,
Motor shaft angle detection means for detecting the angle of the output shaft of the intermediate press motor;
An intermediate presser height control means for performing variable height control for reducing the torque of the intermediate presser motor to be lower than that at the time of increase so that the lowering of the intermediate presser can be stopped by the pressing force at the time of contact with the workpiece;
During the height variable control, when the change of the output shaft of the intermediate presser motor is detected because the intermediate presser is in contact with the sewing product and the lowering is stopped halfway, the intermediate presser corresponding to the angle change is detected. A sewing machine comprising a thickness acquisition processing means for performing a thickness acquisition process for obtaining the thickness of the sewing product from the height of the presser. After obtaining the thickness of the sewing product in the height variable control, pressure control is performed to gradually change the torque value of the intermediate presser motor so that the contact pressure to the sewing product by the intermediate presser increases. Medium pressing pressure control means;
When the lowering of the intermediate presser is detected by the motor shaft angle detecting means during the execution of the pressing control, the torque value of the intermediate presser motor at the time of the lowering, and the hardness of the sewing product obtained from the torque value are determined. The sewing machine according to claim 1, further comprising a hardness acquisition processing unit for recording.   The hardness acquisition processing means is based on the acquired torque value of the intermediate presser motor or the hardness of the sewing product, and at least one of the set thread tension of the thread tension adjusting means and the torque of the sewing machine motor. The sewing machine according to claim 2, wherein the setting is corrected.

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