KR20100064344A - Sewing machine - Google Patents

Abstract

PURPOSE: A sewing machine is provided to reduce manufacturing costs while preventing floating of an object to be sewn by a center presser foot regardless of change of a sewing state of kinds of the object to be sewn. CONSTITUTION: A sewing machine includes the following: a principal axis angle detecting unit detecting an angle of a main shaft which is driven by a motor; a center presser foot(29) preventing floating an object to be sewn; a center presser foot up and down unit moving the center presser foot; a center presser foot height adjusting unit adjusting a height of the presser foot; and a height control unit of the center presser foot controlling a center presser foot motor(42). The height control unit of the center presser foot controls the center presser foot motor to maintain the final output shaft angle of a variable control section.

Description

Sewing machine {SEWING MACHINE}

The present invention relates to a sewing machine having a central presser foot.

Conventionally, in a sewing machine for forming a needle stitch of a predetermined shape while moving a frame-shaped fabric retaining member for retaining fabric with respect to a moving position of the sewing needle, the fabric holding member has a holding force near the center of the frame. When the sewing needle rises, the sewing material is pulled up due to the frictional resistance with the sewing needle when the sewing needle rises, so-called 'fluffing phenomenon' occurs, and the sewing quality deteriorates due to the improper thread tension of the needle stitches. There was.

For this reason, the center presser foot which presses the to-be-processed object by an elastic force is moved by the stroke smaller than the needle to prevent the to-be-drawn object to attract | attract at the time of a rise of a sewing needle. However, since the center presser foot is moving at a lower position than the sewing needle, in the case of a to-be-sealed material, the center presser foot is lowered to a predetermined level or more, and the center presser foot presses the to-be-sealed object with a predetermined force or more, so that the center presser foot is pressed. There was a problem that the traces of the pressurization portion of the left part in the to-be-sealed material deteriorated the quality of the product.

Thus, for example, as described in Patent Document 1, a stepping motor for adjusting the up and down position of the reference position of the center presser foot is provided separately from the sewing machine motor, and the thickness data of the to-be-sealed object is stored in advance, and according to the thickness data during sewing. By operating the stepping motor, the upper and lower positions of the reference position of the center presser foot are adjusted, and the center presser foot is moved up and down at a position suitable for the thickness of the workpiece.

In addition, Patent Document 1, a sewing machine is provided with a cloth thickness detector made of an optical element for detecting the thickness during sewing, and performs a control to adjust the bottom dead center height of the center presser foot by the stepping motor based on the detected cloth thickness. Is described.

[Patent Document 1] Japanese Patent Publication H7-44983 (Fig. 5)

However, in the conventional sewing machine of patent document 1, since the number of working steps for preparing the thickness data of the to-be-sealed object is needed beforehand, there existed a problem that production efficiency became low.

Moreover, when the thickness data of the to-be-sealed object is not prepared beforehand, since the exclusive cloth thickness detector is essential, there existed a problem that productivity fell as the number of components increased.

In addition, a cloth thickness detector must be disposed around the needle bar where the object to be sewn is located. In a sewing machine having a central presser foot, the cloth presser and the shank moving mechanism are provided so that the cloth thickness detector is arranged around the needle bar. There was also a problem that it was difficult to secure space.

Furthermore, when sewing a to-be-finished material such as wool material, the to-be-finished material is in a so-called fluffy state (bulky state), and the cloth thickness detector cannot detect such a fluffy cloth thickness, so There is a problem with the height adjustment precision.

In addition, since the detection of the cloth thickness by the cloth thickness detector and the control of the stepping motor for adjusting the center presser foot height by the detected cloth thickness cannot be performed for each needle during sewing, the response of the needle stitch longer than one needle stitch is delayed. In the case where there is a thick end or the like in the sewing area, the height adjustment of the center presser foot cannot follow a sudden change in thickness, thereby causing a problem of damaging the sewing object.

In addition, it is preferable that the original presser foot is pressurized by the elastic force as described above in the conventional center presser foot. In this state, it was not possible to do so.

An object of the present invention is to stably reduce the cost of an object to be sealed by the central presser foot at all times regardless of the type of the object or the state of sewing.

According to the invention of claim 1, there is provided a frame-shaped cloth holding member for holding the cloth, a needle shank synchronizing tool for rotating the main shaft by rotating the main shaft by a sewing machine motor, and the sewing needle in the frame of the cloth holding member. A moving means for moving the cloth holding member to move up and down, a central presser foot in contact with the to-be-engaged material to prevent injury of the to-be-engaged material during sewing, and a power source from the sewing machine motor, A bottom presser foot height of the center presser foot is changed to an arbitrary height by having a center presser foot shandong mechanism for synchronously moving the center presser foot, a center presser foot motor, and a rotation angle of the center presser foot motor to an arbitrary angle, Bottom dead center of the center presser foot by providing a holding torque for maintaining the rotation angle to the center presser foot motor. A sewing machine having a center presser foot height adjusting mechanism for maintaining a height, wherein a section from the beginning of the descending or descending of the center presser foot to the bottom dead center is balanced with respect to a torque that receives the torque of the center presser foot motor from the outside. The center presser foot is controlled so as not to cause rotation of the output shaft of the center presser foot motor, and based on the reaction force received by the center presser foot from the to-be-sealed object during the lowering of the center presser foot. As the angle of the output shaft of the motor changes, a variable control of the height at which the center presser foot stops midway at a height corresponding to the thickness of the to-be-sealed object is performed, and the section from the bottom dead center of the center presser foot to the next start of descent or descent Silver maintains the center presser foot at a height corresponding to the thickness of the to-be-sealed material To be in the center of the presser foot motor, it characterized in that it includes a central foot height control means for performing control of maintaining the height to give the holding torque.

The invention as set forth in claim 2 has the same configuration as the invention as set forth in claim 1, and is provided with section setting means for setting a main axis angle at which a section for performing the variable control of the height is started.

The invention according to claim 3 has the same configuration as the invention according to claim 1 or 2, and the center presser foot height control means is a position in which the center presser foot rises above the sewing object in each needle in the holding control of the height. , The center presser foot motor is controlled to return the bottom dead center height of the center presser foot to a constant height.

The invention according to claim 4 has the same configuration as the invention according to claim 1 or 2, and further includes a motor shaft angle detecting means for detecting a rotation angle of the output shaft of the center presser foot motor, and the center presser foot height control means. In the height maintenance control, the center presser foot motor is controlled to maintain the rotation angle of the output shaft of the center presser foot motor detected by the motor shaft angle detection means when the variable control of the height is terminated. do.

The invention according to claim 5 has the same configuration as the invention according to claim 1, and further includes motor shaft angle detection means for detecting a rotation angle of the output shaft of the center presser foot motor, wherein the center presser foot height control means, The height maintaining control is characterized in that the torque of the central presser foot motor is returned to the holding torque so as to maintain the center presser foot at a height corresponding to the rotation angle detected by the motor shaft angle detecting means.

The invention according to claim 1 performs variable control of the height of the center presser foot when the center presser foot descends while moving. For this reason, when a contact is made with the descending of the center presser foot by the sewing machine motor, and the reaction force is raised to raise the bottom dead center of the center presser foot by the center presser foot shank / dong mechanism, Since the presser foot motor has been performing torque output to balance the torque received from the outside until then, the current bottom dead center height cannot be maintained (the output shaft is maintained at an angle), and the center presser foot is pushed upward to return. The output shaft of the center presser foot motor generates a rotation in the direction of rotation (the sewing machine motor gives downward movement, and the center presser foot motor rotates in the rising direction, so the center presser foot maintains the height at the time of contact with the workpiece). .

For this reason, even if the descending center presser foot abuts when the to-be-sealed material is thick, the center presser foot maintains the height at the time of contact with the to-be-sealed object, and it is possible to avoid the situation of damaging the pressurized object.

Furthermore, in the height retention control, after the bottom dead center of the center presser foot, the torque value is returned to the holding torque and the axial angle at the bottom dead center is maintained, whereby the sewing object is pulled up by the rising needle to rise. It can fully exhibit the original function of the center presser foot which prevents it.

That is, according to the above invention, the center presser foot is precisely adjusted to the height according to the thickness of the object to be stitched during sewing without stopping the sewing even if the thickness of the cloth changes, and the operation such as interference of the center presser foot is performed in advance. It is possible to relieve the burden, such as, and at the same time, it is possible to cope with the thickness of the object to be sewing, not only the sewing machine for setting the sewing pattern in advance.

In addition, the above-described invention performs control to stop the center presser foot after contacting the to-be-sealed material, so that the to-be-sealed material can be pressurized with a cloth thickness corresponding to the thick state of the to-be-sealed material, thereby preventing flapping of the to-be-sealed object. By exerting the original function of the presser foot, it is possible to effectively reduce the flutter. Further, the present invention performs the control to maintain the height when the center presser foot is lowered and touched, so that, for example, the detection of the cloth thickness and then the height of the center presser foot to control the height of the center presser foot to be an appropriate bottom dead center height are detected. Unlike the case of performing the two-step processing of " control ", the response delay of more than one needle can be avoided, and the center presser foot can be adjusted to an appropriate height for each needle.

Furthermore, the above invention can cope with the center presser foot with the cloth thickness without using the cloth thickness detector for detecting the contact position, the distance, and the like, and the productivity can be improved by reducing the number of parts.

In addition, the structure of this invention may add the motor shaft angle detection means of a center presser foot motor. The motor shaft angle detection means of the center presser foot motor is not limited to the detection of the cloth thickness, and thus has high general versatility. Since it can also be used in combination with other applications, such as for controlling power savings such as switching large, the motor shaft angle detection means can also be used for such applications, thereby reducing the number of parts. will be.

Furthermore, since the present invention does not require a configuration around the needle bar like a cloth thickness detector, it is possible to secure a wide space around the needle bar as a work space, and at the same time, there is no obstacle in mounting other mechanisms or members around the needle bar of the sewing machine. It doesn't work.

And according to this invention, the center presser foot mechanism does not employ | adopt the conventional center presser foot mechanism which presses a to-be-sealed object using elastic force, and can achieve the center presser foot mechanism which does not use elastic force.

The main axis angle at which the variable control of the height is started may be at or below the starting position of the center presser foot, that is, the top dead center position, and there is no limitation as to which angle during the lowering is to be used. It is preferable to set it as the main axis angle in which the height of the center presser foot in the main axis angle at which the variable control of the height is started is greater than the value that the thickness of the product can take.

In addition, "the output which balances the torque of the center presser foot motor with respect to the torque which receives from the outside" in height control is always lowered like the presser spring 30 (refer FIG. 5) which a center presser foot mentions later, for example. When it is pressurized by, it corresponds to the output of the torque in the upward direction to counterbalance the external torque in the downward direction applied to the output shaft of the central presser foot motor by the pressure spring (30). In addition, in a sewing machine that does not have a configuration such as a pressure spring, the torque in the upward direction counterbalances the external torque in the downward direction applied to the output shaft of the central presser foot motor, for example, by the weight of the central presser foot or each member supporting the same. This is equivalent to outputting.

On the other hand, the torque of the central presser foot motor in a period other than the variable control of the height is set to a torque value larger than that of the variable control of the height and capable of sufficiently pressing the sewing object when the sewing needle is removed from the sewing object.

The invention according to claim 2 is provided with section setting means for setting the main axis angle at which the section for performing the variable control of height is started, so that the variable control of the height can be started at an appropriate timing in accordance with the thickness of the workpiece. .

In the invention according to claim 3, the center presser foot motor is controlled so that the whole moving distance of the center presser foot by the sewing machine motor is pushed upward by the variable control of the height when the sewing object is pressed strongly. A control is performed to return the shank east range of the central presser foot pushed up by the variable control of height to a certain height. As a result, the bottom dead center is corrected upward by the previous height variable control to prevent the situation of being excessively separated from the object to be sewn at the next lowering of the central presser foot, so that the object of the object to be pressed can be pressed well every needle. .

In addition, it is preferable to set it as the height which the top dead center of a center presser foot becomes a position higher than the thickness of the thick to-be-sealed material which can be a sewing object, and the bottom dead center of a center presser foot becomes a needle plate upper surface.

Further, the control for lowering the bottom dead center of the center presser foot does not indicate a state in which the sewing needle is pulled out of the sewing object (the lower end of the sewing needle is completely out of the upper surface of the sewing object, and the sewing needle is caused by friction. It is preferable to carry out from the state of pulling up the to-be-sealed object together, and to the angle of the main axis which starts the variable control of height after passing the main axis angle which a center presser foot raises.

Hereinafter, with reference to the drawings will be described in detail an embodiment of the sewing machine according to the present invention.

In this embodiment, the electronic cycle sewing machine will be described as an example of the sewing machine.

The electronic cycle sewing machine has a frame-shaped holding frame 111 (cloth holding member) for holding a cloth, which is an object to be sewn, and a moving means to move the holding frame in the XY direction by a stepping motor, and the holding frame is It is a sewing machine which forms needle stitches based on predetermined sewing data (sewing pattern) on the fabric held by the holding frame as it moves relative to the sewing needle.

Here, the direction in which the sewing needle 108, which will be described later, moves up and down is called the Z-axis direction (up and down direction), and one direction orthogonal to this is the X-axis direction (left and right direction), both the Z-axis direction and the X-axis direction. The direction orthogonal is defined as the Y-axis direction (front and rear direction).

Electronic cycle sewing machine (100, hereinafter referred to as "sewing machine 100"), as shown in Figure 1, the sewing machine main body 101 is provided on the upper surface of the sewing machine table (T), the lower portion of the sewing machine table (T) It is provided with a pedal (R) for operating the sewing machine main body 101, and is provided on the top of the sewing machine table (T) and is provided with an operation panel 74 for performing an input operation by the user.

(Sewing machine frame and spindle)

1 and 2, the sewing machine main body 101 has a sewing machine frame 102 having an approximately inverted c shape when viewed from the side. The sewing machine frame 102 forms a lower portion of the sewing machine arm portion 102a and the sewing machine main body 101, and connects the sewing machine bed portion 102b, the sewing machine arm portion 102a, and the sewing machine bed portion 102b. It has a vertical body part 102c.

The sewing machine main body 101 has a power transmission mechanism disposed in the sewing machine frame 102, and has a main shaft (2, FIG. 4) that is rotatable and extends in a front-rear direction 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 the sewing machine motor 2a (refer to FIG. 8), and is provided with a turning force by the sewing machine motor 2a. In addition, the lower shaft (not shown) is connected to the main shaft (2) through the vertical axis (not shown), and when the main shaft (2) rotates, the power of the main shaft (2) is transmitted to the lower shaft through the vertical axis so that the lower shaft is rotated. It is.

A needle bar 108a which moves up and down in the Z axis direction is connected to the front end of the main shaft 2, and a sewing needle 108 is connected to the lower end of the needle bar 108a. It is installed to be exchangeable. That is, the sewing needle 108 moves in the Z-axis direction as the main shaft 2 rotates.

The needle shank-dong mechanism is constituted by such a main shaft 2, the sewing machine motor 2a, the needle bar 108a, and the unshown transmission mechanism that imparts the driving force of the shank-dong from the spindle 2 to the needle bar 108a.

In addition, the main shaft 2 is provided with an encoder 2b (see FIG. 7) as the 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 1000 controls the pulse signal every time the main shaft 2 is rotated by 1 ° by the sewing machine motor 2a. It is supposed to output to. In addition, the needle bar 108a performs one reciprocating motion according to one rotation of the main shaft 2.

In addition, a kiln (not shown) is provided at the front end of the lower axis (not shown). When the lower shaft rotates together with the main shaft 2, needle stitches are formed by the cooperation of the sewing needle 108 and the kiln (not shown).

In addition, 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 kiln (not shown) and the like are the same as the conventionally known ones. The description will be omitted.

(Positioning means)

As shown in Fig. 1 and Fig. 2, the needle plate 110 is provided on the sewing machine bed portion 102b, and above the needle plate 110, a holding frame 111 as a cloth holding portion and a sewing needle ( 108 is arranged.

The holding frame 111 is attached to the attachment member 113 disposed at the front end of the sewing machine arm portion 102a, and the attachment member 113 is the X-axis motor 76a disposed in the sewing machine bed portion 102b. And the Y-axis motor 77a are connected as driving means (moving means) (see Fig. 7).

The holding frame 111 holds the base fabric as a to-be-sealed object, and moves the held base fabric in the front-back / left-right direction together with the holding frame 111 by the driving of the X-axis motor 76a and the Y-axis motor 77a. It is supposed to be. As the movement of the holding frame 111 and the operation of the sewing needle 108 or the kiln (not shown) are linked, needle stitches are formed on the base fabric based on the needle stitching data of the predetermined sewing pattern data.

In addition, the holding frame 111 is composed of a presser foot (not shown) and a lower plate (not shown), and the attachment member 113 is driven up and down by driving of the presser foot motor 79b disposed in the sewing machine arm portion 102a. When the presser foot descends, the base fabric is sandwiched between the lower plate and held.

Then, the holding frame 111, the attachment member 113, the X-axis motor 76a and the Y-axis motor 77a position the sewing needle and the ground cloth relatively in the X-axis direction and the Y-axis direction. It functions as a means.

The pedal R drives the sewing machine 100 to act as an operation pedal for moving the needle bar 108a (sewing needle 108) or operating the holding frame 111. That is, the pedal R And a sensor for detecting the depression operation position where the pedal R is stepped on, and the output signal from the sensor is output to the control device 1000 described later as an operation signal of the pedal R, and the control device 1000 ) Is configured to operate by operating the sewing machine 100 in accordance with the operation position, the 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 inputted to the operation panel 74 are transferred to the control apparatus 1000 described later. Is output.

In addition, 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 the touch panel touches the touch panel by touching the various operation keys displayed on the liquid crystal display panel. The detected position is output, and an operation signal corresponding to the detected position is output to the control apparatus 1000 described later.

(Center presser foot device)

The sewing machine arm portion 102a is moved in conjunction with the shanghai dong of the needle bar 108a to prevent injuries of the fabric caused by the shanghai dong of the sewing needle 108, and moves around the sewing needle 108. The center presser foot device 1 (refer FIG. 3) which has the center presser foot 29 which presses a cloth downward is provided. Moreover, the main body of the center presser foot device 1 is provided in the inside of the sewing machine arm part 102a, and the sewing needle 108 is inserted in the through-hole formed in the front end side of the center presser foot 29. As shown in FIG.

3 to 5, the center presser foot device 1 is a needle presser which moves up and down in accordance with the rotation of the main presser foot 29 and the spindle 2 to press the fabric toward the needle plate 110 during sewing. 108 to enable the escape operation performed when the lowering operation of the central presser foot shank moving mechanism M1 and the central presser foot 29 is impeded in order to move the central presser foot 29 to the shank at the same time. A presser mechanism M2 for pressing the center presser foot 29 toward the needle plate 110, a center presser foot evacuation mechanism M3 for raising the center presser foot 29 to the retracted height position after finishing sewing, and a center presser foot 29 It is provided with a center presser foot height adjustment mechanism (M4) for adjusting the height.

The central presser foot shank moving mechanism M1 moves the central presser foot 29 to the shank east side according to the rotation of the main shaft 2 (refer to FIG. 4) which drives the needle bar 108 having the sewing needle 108 at the tip in the vertical direction. It is supposed to be.

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. The oscillation shaft holder 5 is connected to the connection link 4, and one end of the oscillation shaft 6 is connected to the oscillation shaft holder 5.

As shown in FIG. 5, the base end of the center presser foot adjustment arm 7 which adjusts the movement amount of the center presser foot in the up-down direction D1 is being fixed to the other end of the swing shaft 6. A groove cam 7a is formed in the central presser foot adjustment arm 7. The groove cam 7a is an arc-shaped long hole, and one end of the first link 8 at the desired position of the groove cam 7a has an adjusting nut 9 and a stepped screw 10. It is axially supported by. The fixed position of one end of the first link 8 is capable of adjusting the movement of contact and separation with respect to the center of the swing shaft 6, and the amount of reciprocating operation given to the first link 8 in proportion to the distance from the center. You can adjust the increase and decrease.

As shown in FIG. 5, the other end of the first link 8 is rotatably connected by a stepped screw 12 at approximately the middle of the second link 11 in the longitudinal direction. Here, the groove cam 7a to which the adjusting nut 9 engages has a part of a circular arc centered on the shaft center of the stepped screw 12 when the center presser foot 29 is at the bottom dead center of the up and down reciprocating motion. It is formed to be. In other words, when the angle of the upper shaft 2 is in a phase of moving the center presser foot 29 to the bottom dead center, the bottom adjustment of the center presser foot 29 is performed by adjusting the position of the first link 8 in the groove cam 7a. The stroke can be adjusted while the point position is floating.

One end of the second link 11 is axially supported by the positioning link 13 described later. As one end of the second link 11 is axially supported by the positioning link 13, when the center presser foot 29 is moved up and down during normal sewing, the second link 11 is caused by the elastic force of the tension spring 16. One end of the c) is kept pressed by the regulating member 19. And, when the center presser foot 29 cannot press the base fabric strongly or fall down to a predetermined bottom dead center position, the positioning link 13 rotates against the elastic force of the tension spring 16. As the supporting point of one end of the two links 11 descends against the tension spring 16, the center presser foot 29 can be lifted upward. This prevents damage to the central presser foot shank moving mechanism M1.

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 stepped screw 21. One end of the fourth link 22 is rotatably connected to the other end of the third link 20 so that the one end of the fourth link 22 is in series with the longitudinal direction of the third link. In the present embodiment, the center presser foot link member 24 is configured by the third link 20 and the fourth link 22.

The link relay plate 25 is connected to the other end of the fourth link 22 by a stepped screw 26. The center presser foot holder 27 is fixed to the link relay plate 25, and the center presser foot stand 28 extending in the vertical direction is held in the center presser foot holder 27. At the lower end of the center presser foot stand 28, a center presser foot 29 is attached to press the base fabric toward the needle plate 110 during sewing. A pressure spring 30 is provided at the upper end of the center presser foot stand 28, and is attached to the center presser foot holder 27 by a bolt 31 and a nut 32. The presser spring 30 always presses the center presser foot 29 downward when the center presser foot 29 moves in synchronism with the sewing needle 108 at the time of sewing.

In the present embodiment, the central presser foot shank moving mechanism M1 is configured by the first link 8, the second link 11, the third link 20, the fourth link 22, and the like.

The stepped screw 23 connects the third link 20 and the fourth link 22 together with the square pieces 33 and the guide member 34. That is, the guide member 34 is provided on the front side of the fourth link 22, and the square piece 33 is installed on the front side of the guide member 34, and the third link 20, The four links 22, the square pieces 33, and the guide member 34 are connected by one stepped screw 23. As shown in FIG.

The guide member 34 is a substantially F-shaped plate material, and the upper end portion 34t is rotatably attached to the sewing machine housing (sewing machine frame 102) by a stepped screw 35. In the vicinity of the lower end of the guide member 34, a hole 34a having a long length in the vertical direction is formed. The long hole 34a has a rectangular piece 33 slidably fitted therein, and the guide member 34 has a center presser foot around the connecting portion P of the third link 20 and the fourth link 23. 29 is movable in the up and down direction D1, and the movement in the direction D3 across the serial direction D2 of the third link 20 and the fourth link 22 is regulated.

In addition, as shown in FIG. 5, the guide member 34 includes the guide member 34 in a direction D3 crossing the series direction D2 of the third link 20 and the fourth link 22. One end of the movable link 36 to be moved to the upper side is rotatably connected to the upper vicinity of the long hole 34a by a stepped screw 37. An eccentric cam 38 is connected to the other end of the movable link 36, and one end of the 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 the central presser foot motor 42 through a bearing 40 and an umbrella gear 41. That is, the driving of the center presser foot motor 42 is transmitted in the order of the variable shaft 39, the eccentric cam 38, and the moving link 36, so that the moving link 36 is used to adjust the rotation angle of the guide member 34. The tilt is changed and adjusted.

The central presser foot motor 42 can rotate in the forward and reverse directions, and the rotation amount and timing of the drive can be controlled by the control device 1000.

Then, the movable link 36, the guide member 34, the square piece 33, and the like are constituted as an operation transmission member of the central presser foot shank moving mechanism, and the rotation angle of the central presser foot motor 42 is changed to an arbitrary angle. By changing the inclination of the motion transfer member, the height of the bottom dead center of the center presser foot 29 by the center presser foot shank moving mechanism M1 to be described later is changed to an arbitrary height, and the rotation angle of the center presser foot motor 42 is further changed. It functions as a center presser foot height adjustment mechanism M4 which maintains the bottom dead center height of the center presser foot 29 by the center presser foot shank moving mechanism M1 by providing the holding torque to hold.

The positioning link 13 is rotatably attached to the sewing machine frame 102 as a sewing machine housing by a stepped screw 14 near its central portion, and the position of the stepped screw 14 is located at the center presser foot 29. This step coincides with the position of the stepped screw 12 at the bottom dead center.

One end of the positioning link 13 is folded in a substantially inverted c shape toward the sewing machine face, and a spring hook 13a is formed on the folded end. In the positioning link 13 in this embodiment, one end of the spring hook 13a is folded to the vicinity of the stepped screw 14 which is the rotation center of the positioning link 13, and the spring is rotated from the rotation center. It is formed so that the distance to the hook 13a may become short. One end (upper end) of the tension spring 16 is connected to the spring hanger 13a, and the other end (lower end) of the tension spring 16 is connected to a spring hanger 15 fixed to the sewing machine frame.

The tension spring 16 is urged to pull down one end of the positioning link 13 on which the spring hook 13a is formed. That is, when the tension spring 16 receives the reaction force upward by being strongly pressed by the center presser foot 29 when the connection portion with the third link 20 in the second link 11 receives the reaction force. The pressure is applied to pull the connection portion downward. That is, the tension spring 16 and the positioning link 13 enable the escape operation for avoiding excessive load on the central presser foot shank moving mechanism M1 when the lowering operation of the central presser foot 29 is inhibited. At the same time, it functions as a pressurizing mechanism M2 for pressing the center presser foot 29 toward the needle plate 110 during the evacuation operation. And the tension spring 16 functions as a press spring for avoiding excess load.

In addition, the pressurizing mechanism M2 is connected to the central presser foot shank moving mechanism M1 as the positioning link 13 is connected 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 one end screw 18. It is. The stopper 17 is rotatably attached to the sewing machine frame 102 together with the positioning link 13 by a stepped screw 14. Above the one end 17a of the stopper 17, a restricting member 19 is provided to restrict the one end of the stopper 17 from moving upward. In addition, the restricting member 19 may be substituted as a part of the sewing machine frame 102.

As shown in FIG. 4, the umbrella gear 43 is engaged with the umbrella gear 41 so that the drive of the central presser foot motor 42 can be output in the direction D4 orthogonal to the axial direction of the variable shaft 39. have. At the rear end of the umbrella gear 43, a bearing 44, a central presser foot lifting cam 45, and the like are connected coaxially.

The center presser foot lifting cam 45 is a groove cam having a groove not shown in the axial cross section.

The center presser foot raising and lowering cam 45 has a cam portion, and half of the rotation range of the center presser foot raising and lowering cam 45 is formed in an arc shape having substantially the same distance from the center of rotation to the groove (hereinafter, referred to as a cam). In the other half, the distance from the center of rotation to the groove is greater than the distance from the center of rotation to the groove at the holding part, and the shape changes smoothly (hereinafter referred to as the 'change part'). )

The center presser foot lifting cam 45 is to lift up and down one end 46a of the center presser foot raising member 46 which raises the center presser foot 29 to the retreat position after the end of sewing. The cylindrical roller 47 provided in the other end of the center presser foot raising member 46 is slidably fitted in the groove | channel of 45). And when the roller 47 moves along the holding | maintenance part of the center presser foot lifting cam 45, the one end part 46a of the center presser foot lifting member 46 will not raise or fall, but the roller 47 will move up the center presser foot lifting cam 45. When moving along the change portion of), one end portion 46a of the central presser foot raising member 46 is moved up and down.

Since the other end of the presser foot lifting member 46 is engaged inside the groove (not shown) of the center presser foot lifting cam 45 which is such a groove cam, the center presser foot lifting cam 45 rotates. As long as it does not, the center presser foot raising member 46 can maintain a constant state without oscillation. And the center presser foot lifting | retraction cam 45, the center presser foot raising member 46, and the roller 47 form the center presser foot retraction mechanism M3.

The center presser foot raising member 46 is rotatably attached to the sewing machine frame 102 by a shaft member, that is, a pin 48 at its intermediate portion. The center presser foot raising member 46 is provided such that one end portion 46a is located below the center presser foot holder 27, and the roller 47 moves along the change portion of the center presser foot lifting cam 45. As the one end portion 46a of the center presser foot raising member 46 rises, the center presser foot holder 27 is raised to raise the center presser foot 29 to the retracted position.

(Movement of the center presser foot at the time of sewing)

Next, operation | movement of the center presser foot shank moving mechanism M1 of the center presser foot device 1 which has the said structure is demonstrated.

When the main shaft 2 is rotated by the drive of the sewing machine motor 2a to rotate the eccentric cam 3, the tip of the connecting link 4 is in a direction substantially perpendicular to the axis of the main shaft 2 (third link 20 ) And the swing shaft holder 5 connected to the connecting link 4 also swing in the same direction as the cross direction D3 of the fourth link 22. As the swing shaft holder 5 swings, the swing shaft 6 also swings, so that one end of the first link 8 becomes a swinging point and the other end of the first link 8 moves to the swing shaft 6. It oscillates in the direction substantially orthogonal to an axis line (direction D3 which transverses with respect to the serial direction D2 of the 3rd link 20 and the 4th link 22). According to the swing of the other end of the first link 8, the other end of the second link 11 swings in the series direction D2 of the third link 20 and the fourth link 22, and the second link The third link 20 and the fourth link 22 connected to the other end of (11) swing in the series direction (up-down direction; D2). In accordance with the fluctuations of the third link 20 and the fourth link 22, the center presser foot 28 connected to the fourth link 22 moves along the vertical direction D1, so that the center presser foot 29 is moved. Move up and down. In addition, since the sewing needle 108 is moved in accordance with the rotation of the main shaft (2), the center presser foot 29 is moved to the shandong to move in conjunction with the shankdong of the sewing needle (108).

In the following description, the sewing needle 108 and the center presser foot 29 are positioned at the top dead center when the angle of the main shaft 2 is 0 °, and the sewing needle 108 when the angle of the main shaft 2 is 180 °. And the center presser foot 29 are located at the bottom dead center.

(Adjustment of the bottom dead center height of the center presser foot by the center presser foot device)

Next, the adjustment operation | movement with respect to the height of the center presser foot 29 by the center presser foot height adjustment mechanism M4 of the center presser foot device 1 which has the said structure is demonstrated.

The drive of the center presser foot motor 42 is transmitted to the movable shaft 39 through the umbrella gear 41 and the bearing 40, and the movable shaft 39 starts to rotate. As the movable shaft 39 rotates, the eccentric cam 38 also rotates, and the movable link 36 is in a direction substantially orthogonal to the axis of the movable shaft 39 (third link 20 and fourth link 22). Rocking in the direction D3 crossing the series direction D2. As the movable link 36 swings, the guide member 34 swings in the direction D3 transverse to the series direction D2 of the third link 20 and the fourth link 22.

At this time, as shown in Fig. 6 (a), (b) of the connecting portion (P) of the third link 20 and the fourth link 22 connected through the long hole 34a of the guide member 34. The stepped screw 23 (square piece 33) is a direction in which the screw portion crosses the serial direction D2 of the third link 20 and the fourth link 22 by the long hole 34a. Since movement to (D3) is restricted (see FIGS. 5 and 6 (a)), there is no place to escape the force transmitted by the swing, and the stepped screw 23 (square piece 33) The third link 20, which moves upward along the long hole 34a and follows the guide member 34 of the stepped screw 23 (square piece 33), is connected side by side in series. And the angle formed by the fourth links 22 are changed so that the center presser foot link member 24 becomes approximately <shape (see Fig. 6B). , The center presser foot 29 is moved up and down (D1) The bottom dead center height of the center presser foot 29 from the needle plate 110 of the center presser foot 29 is changed by changing the rotation angle of the center presser foot motor 42 to an arbitrary angle. Furthermore, the bottom dead center of the center presser foot 29 by the center presser foot shank moving mechanism M1 changed to the said arbitrary angle by giving the center presser foot motor 42 the holding torque which maintains a rotation angle is provided. Maintain the height

(Control system of sewing machine: controller)

In addition, the sewing machine 100 is provided with a control device 1000 as an operation control means for controlling the operation of each of the above-described parts, each member, as shown in FIG. The control device 1000 stores a program memory 70 in which a sewing program 70a and a central presser foot height control program 70b are stored, sewing pattern data 71a, and various setting information (not shown). As a data memory 71 and a CPU 73 for executing each of the programs 70a and 70b in the program memory 70.

In addition, the CPU 73 is connected to the operation panel 74 through the interface 74a. The operation panel 74 has a display portion 74b for displaying various screens and input buttons and a touch sensor 74c provided on the surface of the display portion 74b to detect the contact position thereof, and functions as an input / output means for various kinds of information. do. All input buttons or input switches used in the operation panel 74 are displayed on the display unit 74b, and function as the push button or switch as the input is detected by the touch sensor 74c.

In addition, the CPU 73 is connected to the sewing machine motor drive circuit 75b which drives the sewing machine motor 2a through the interface 75, and controls the rotation of the sewing machine motor 2a. In addition, the sewing machine motor 2a includes an encoder 2b, which is output from the encoder 2b every one revolution of the sewing machine motor 2a in the sewing machine motor drive circuit 75b for driving the sewing machine motor 2a. The Z-phase signal is input to the CPU 73 through the interface 75, and according to the signal, the CPU 73 can recognize the origin (0 ° position) in one revolution of the main shaft 2. have. Moreover, the A phase signal output by every 1 degree at the rotation angle of the sewing machine motor 2a is input from the encoder 2b to the CPU 73 via the interface 75, and is based on the Z phase signal mentioned above. By counting the number of pulses of the A-phase signal, the CPU 73 can recognize the current rotation angle of the main shaft 2.

On the other hand, for example, a servo motor can be applied to the sewing machine motor 2a.

In addition, the CPU 73 drives the X-axis motor 76a and the Y-axis motor 77a, which are provided in the holding frame 111 for holding the base fabric to be sewn, through the interface 76 and the interface 77, respectively. The X-axis motor drive circuit 76b and the Y-axis motor drive circuit 77b are connected to control the operation in the X-axis direction and the Y-axis direction of the holding frame 111.

Moreover, the CPU 73 presses the center presser foot motor which drives the center presser foot motor 42 which can move the center presser foot 29 separately from the shanghai copper by the sewing machine motor 2a via the interface 78. The drive circuit 78b is connected and controls the operation of the center presser foot mechanism 1. In addition, the encoder 81 serving as the motor shaft angle detection means is provided on the output shaft of the center presser foot motor 42, and the encoder 81 is provided in the center presser foot motor driving circuit 79b for driving the center presser foot motor 42. The Z-phase signal outputted at each rotation of the center presser foot motor 42 is input to the CPU 73 through the interface 78, and by the signal, the CPU 73 output shaft of the center presser foot motor 42. The origin (0 ° position) can be recognized at one rotation. Moreover, from the encoder 81, the A-phase signal output by every 1 degree at the rotation angle of the center presser foot motor 42 is input to the CPU 73 via the interface 78, and the Z-phase signal mentioned above is referenced. By counting the number of pulses of the A-phase signal, the CPU 73 can recognize the current rotation angle of the output shaft of the center presser foot motor.

The CPU 73 is connected to the presser foot motor drive circuit 79b for driving the presser foot motor 79a for moving the presser foot (not shown) up and down through the interface 79 to control the operation of the presser foot.

In addition, a stepping motor can be applied to the X-axis motor 76a and Y-axis motor 77a, the center presser foot motor 42, and the presser foot motor 79a, for example.

As shown in Fig. 8, the sewing pattern data 71a stored in the data memory 71 moves when the holding frame 111 is moved to execute a needle movement pattern when sewing is performed. The cloth feed command, the air feed command, the thread cutting command, and the end command, which indicate the X-axis movement amount and the Y-axis movement amount (needle stitch data indicating needle drop position), are combined.

Then, various commands are executed in accordance with the arranged order to perform sewing by an arbitrary pattern (shape).

In the sewing pattern data shown in Fig. 8, the "sewing" and "empty transfer" commands include data (parameters) of the X-direction movement amount and the Y-direction movement amount when the holding frame 111 is moved. The rotational driving amounts of the X-axis motor 76a and the Y-axis motor 77a are determined by these.

In addition, "thread cutting" is a command to operate a thread cutting device (not shown), "end" is a command to drive the presser foot motor 79a of the sewing machine 100 to release the cloth, and the numerical setting for this operation is Since it becomes unnecessary, numerical data is not set (indicated by (0) in FIG. 8).

In addition, the notation in the numerical data of X movement amount, Y movement amount, and central presser foot movement amount of FIG. 8 is 10 times notation, for example, "15" represents "1.5mm".

(Process by central presser foot height control program)

The center presser foot height control program 70b stored in the program memory 70 is a program for adjusting the center presser foot motor 42 to an appropriate height by controlling the center presser foot motor 42 in accordance with the thickness of the object to be sewn at the time of sewing. .

The control performed by the CPU 73 by the center presser foot height control program 70b will be described in detail with reference to FIGS. 9 to 12.

9 is a change in height generated in the center presser foot 29 in which the shank movement and height adjustment are performed by the center presser foot shankdong mechanism M1 and the center presser foot height adjustment mechanism M4 with respect to the change of the main shaft angle due to the rotational drive. A diagram showing a diagram surface (upper view) and a diagram showing a change in the axial angle of the central presser foot motor 42 controlled by the CPU 73 (lower view). 10 (A) is a point bc section of FIG. 9, FIG. 10 (B) is a point c of FIG. 9, FIG. 10 (C) is a point cd section of FIG. 9, and FIG. 10 (D) is a point of FIG. e and FIG. 10E are schematic diagrams showing an operating state of the central presser foot height adjusting mechanism M4 at the respective main shaft angles at the point f in FIG. 9. In addition, in FIG. 10, in order to avoid duplication of components, the bending directions of the links 20 and 22 and the arrangement of the center presser foot motor 42 are reversed from left to right, but this does not affect the explanation of the following principles. It is not.

As described above, the center presser foot 29 is moved in synchronism with the sewing needle 108 so as to be the top dead center at the main axis angle 0 °, and the bottom dead center at the main axis angle 180 ° by the center presser foot shank moving mechanism M1. However, the center presser foot 29 is disposed below the sewing needle 108, and the stroke of the up and down reciprocation is also set shorter than the sewing needle 108.

As the initial position, at the start of sewing, the center presser foot motor 42 is controlled so that the bottom surface of the center presser foot 29 is flush with the needle plate upper surface when the center presser foot 29 is located at the bottom dead center. . In addition, the axial angle of the output shaft of the center presser foot motor 42 at this time is made into 0 degree | times (origin), and it demonstrates as follows.

11 is an explanatory diagram showing a relationship between the main axis angle and the type of control for the central presser foot motor performed by the CPU 73. As shown in Figs. 9 and 11, the CPU 73 reacts with one stroke (one rotation of the spindle 2) in the shanghai-dong of the central presser foot 29, and the central presser foot 29 strongly presses the sewing object. When the control unit receives a variable control of the height for rotating the output shaft of the center presser foot motor 42 in the upward movement direction (height variable control section; K1), and the axial angle of the center presser foot motor 42 is fixed regardless of the external force. The control is performed by being divided into a section (maintenance control section) that performs the maintenance control (maintenance control of height).

The holding control section is a first holding control section for holding the axial angle of the central presser foot motor 42 at the origin from the main shaft angle of 0 ° (top dead center) to the starting main shaft angle of the height variable control section K1. (K2) and after the main spindle angle (180 °) (lower dead center) of the height variable control section K1, the center presser foot motor 42 between the main spindle angle (180 °) and the main shaft angle 0 °. The axial angle is divided into a second holding control section K3 which maintains the axial angle of the central presser foot motor 42 finally modified by the variable control of the height, and the first holding control section K2 and the second holding control section. The control which returns the axial angle of the center presser foot motor 42 to the origin at the main shaft angle (0 °) between K3 is performed. The control for returning the axial angle of the central presser foot motor 42 to the origin may be performed at any timing from when the sewing needle is removed from the sewing object until the variable control of the height is started.

In addition, the height variable control section K1, the first holding control section K2 and the second holding control section K3 have a main axis angle at which the start and end of each section are set in advance and the data memory 77 is set. The CPU 73 monitors the main axis angles at which the respective starting angles are used by the encoder 2b, and starts the control for each section.

By executing the center presser foot height control program 70b, the CPU 73 performs variable control on the height in the height variable control section K1, and executes the first holding control section K2 and the second holding control section ( It functions as the center presser foot height control means for performing the height retention control in K3).

(Height control of the center presser foot: height variable control section)

In the variable control of the height, when the center presser foot 29 presses the to-be-sealed material strongly, the center presser foot motor 42 moves in the ascending direction so as to cancel the downward movement that the sewing machine motor 2 imparts to the center presser foot 29. The rotation is performed to reduce the pressure on the object to be sealed.

That is, the center presser foot motor 42 performs a torque output in the direction of raising the center presser foot 29 with respect to an external torque applied in the direction of lowering the center presser foot 29 with respect to the output shaft to balance the center. The bottom dead center height of the presser foot 29 is maintained, and when the center presser foot 29 descends, the thick end of the to-be-sealed object is pressed hard and stops on the way and receives a reaction force upward. Since the balance of the torque applied to the output shaft of 42) is inclined toward the rising side, the output shaft rotates to the rising side, and the sewing machine motor 2 and the center presser foot motor 42 are brought into contact with the center presser foot 29 by imparting a shank movement. Keep in position.

Both the main axis angle (point b in FIG. 9) at which the height variable control section K1 is started and the main axis angle (dot d in FIG. 9) at the end can be set through the operation panel 74. As shown in FIG.

The starting angle of the variable control of height can be set in the range of 0 degree or more and 180 degrees or less, for example, from the start of descent of the center presser foot 29, or the period from the descent to the bottom dead center, and at least, the thickness of the to-be-sealed object It is assumed that the height is set at the main axis angle at which the central presser foot 29 is located.

In addition, the end angle is, in principle, performed up to the bottom dead center (the main shaft angle 180 °) of the shanghai by the sewing machine motor (2), but fine adjustment can be made for a range up to about 190 ° even after 180 °.

Also, the operation panel 74 functions as "segment setting means for setting the main axis angle at which the section for performing the variable control of height starts and ends".

The variable control of the height is performed by using the up-down position adjustment function of the center presser foot 29 of the center presser foot height adjusting mechanism M4 when the descending center presser foot 29 receives reaction by contact with the object to be sewn. The center presser foot motor 42 is controlled to perform the upward movement so as to cancel the downward movement by the sewing machine motor 2 according to the external force so that the pressing force is not generated on the side.

The center presser foot shank moving mechanism M1 is provided with the pressurizing spring 30 which always presses the center presser foot 29 downward.

From the start of the variable control of the height until the center presser foot 29 contacts the to-be-sealed object, as shown in FIG. 10 (A), by the pressing force f of the pressure spring 30, The counterclockwise torque T1 is applied to the link 22, whereby the clockwise torque T2 acts on the guide member 34. Therefore, the external shaft Tf in the clockwise direction is applied to the output shaft of the central presser foot motor 42 as the "torque received from the outside" through the moving link 36 and the eccentric cam 38.

In order to balance the external torque Tf, the CPU 72 controls to output the drive torque Tm in the reverse direction (counterclockwise) with a magnitude substantially equal to Tf. As a result, it is possible to prevent the rotation of the output shaft of the central presser foot motor 42 during the lowering of the central presser foot 29.

As shown in FIG. 10 (B) and FIG. 12, the left end in FIG. 3 has a second link 11 reciprocated by the sewing machine motor 2 in the central presser foot shank moving mechanism M1. The pressing position is fixed by the tensioning member 16 by the upper restricting member 19, and the left end is made the center of rotation. In addition, the tension spring 16 actually presses the left end of the second link 11 against the restricting member 19 by applying tension through the positioning link 13, but in FIG. 12 for clarity of explanation. The tension spring 16 is shown as a pressure spring while the illustration of the positioning link 13 is omitted.

The second link 11 is provided with a reciprocating turning force from the first link 8 connected to the intermediate position.

In this structure, when the center presser foot 29 is strongly pressed, the right end of the second link 11 that has been rotated up to that time is prevented from descending, so that the first link 8 from the sewing machine motor 2 is stopped. The downward pressing force applied through acts on the left end of the second link 11, trying to push the left end against the tension spring 16.

At this time, the second link 11 receives the torque in the Y1 direction from the tension spring 16 about the connection point with the first link 8 at the left end momentarily away from the restricting member 19. The third link member 20 receives torque in the direction of arrow Y2 and the square piece 33 is pressed in the direction of arrow Y3. Then, the rotational force is applied to the guide member 34 in the direction of the arrow Y4, and the moving link 36 is pressurized in the direction of the arrow Y5 to torque the output shaft of the central presser foot motor 42 through the eccentric cam 38 in the direction of the arrow Y6. (TF) is granted. In addition, compared with the magnitude | size of the torque TF which originates in the said tension spring 16, the magnitude | size of the external torque Tf and the drive torque Tm which originate in the pressurizing spring 30 mentioned above are set small enough. .

On the other hand, since the upper torque Tf from the pressurizing spring 30 is not provided to the output shaft by the contact of the center presser foot 29, the center presser foot motor 42 has its drive torque Tm. And both of the torques TF caused by the tension spring 16 act, so that the rotation of the center presser foot 29 in the upward direction (counterclockwise direction) is easily performed.

That is, the downward movement is imparted to the central presser foot 29 by the sewing machine motor 2a, and the upward movement is imparted by the central presser foot motor 42 so as to offset this. It stops at the upper surface and hardly press force with respect to a to-be-sealed material (FIG. 10 (C)).

(Center presser foot height control: Maintenance control section)

The maintenance control section is, for example, a section from the bottom dead center of the central presser foot 29 to the start of the next fall or the descent, which is two sections, that is, the height variable control section from the main axis angle of 0 ° (point a in FIG. 9). A first holding control section K2 for maintaining the axial angle of the central presser foot motor 42 at an initial position between the starting main shaft angle of K1 and the point B in FIG. 9, and the height variable control section K1. The axial angle of the central presser foot motor 42 from the end of the main axis angle (in principle 180 °: point d in FIG. 9) to the main axis angle 0 ° (points e and f in FIG. Finally, the main shaft is divided into a second holding control section K3, which is maintained at the axial angle of the center presser foot motor 42, and shifts from the second holding control section K3 to the first holding control section K2. Control to return the axial angle of the central presser foot motor 42 to the initial position at an angle (0 °) is performed.

In addition, in the height variable control section K1, the first holding control section K2 and the second holding control section K3, the main axis angles at which the start and end of each section are determined in advance are set by the CPU ( 73 monitors the main axis angle which becomes each starting angle by the encoder 2b, and starts control for each section.

In the first holding control section K2, the CPU 73 sets the command angle of the center presser foot motor 42 to 0 °, which is an initial position value (for example, the height at which the center presser foot 29 is exactly in contact with the upper surface of the needle plate at the bottom dead center). Control of the central presser foot motor 42) is performed. In addition, the CPU 73 controls the current by setting the torque at which the output torque of the center presser foot motor 42 is larger than the load torque T1 by the tension spring 16 as the holding torque T0. As a result, in the first holding control section, even if a state in which the lowering is prevented due to any object being caught by the center presser foot 29 occurs, the center presser foot motor 42 maintains the initial position and at the same time the tension spring 16 ), The escape operation performed when the lowering operation of the center presser foot 29 is inhibited is performed.

Further, in the second holding control section K3, the CPU 73 controls the central presser foot motor 42 to maintain the angle finally reached in the height variable control section K1 until the top dead center is reached (Fig. 10 (D)). Also in this case, the CPU 73 controls the current by setting the torque having the same output torque of the center presser foot motor 42 as the first holding control section K2 to the holding torque T0.

Thus, when the sewing needle 108 passing through the bottom dead center starts to rise in the state of drilling the sewing object, the sewing object is pulled by the sewing needle 108 to be in pressure contact with the central presser foot 29, but the center presser foot. Since 29 maintains a constant height against the pressing force, it is possible to prevent the floating of the to-be-sealed object.

Further, in the second holding control section K3, when the center presser foot 29 reaches the top dead center (point e in Fig. 9), the CPU 73 moves the center presser foot motor 42 to an initial position value of 0 degrees. Control to return to is performed (point f in Fig. 9, Fig. 10D). That is, in the height variable control section K1, when the center presser foot 29 comes into contact with the workpiece and the axial angle of the center presser foot motor 42 is changed, it is returned to the origin position. This makes it possible to avoid the situation where the center presser foot 29 does not reach the to-be-seeded object even when the thickness of the to-be-seamed object becomes thin during the next height variable control, so that it is possible to achieve an appropriate bottom dead center height. 2 It is possible to prevent the injuries of the sealed object in the maintenance control section (K3).

(Sewing processing by sewing program)

The sewing program 70a stored in the program memory 70 reads each command of the sewing pattern data 71a in order to specify a control target according to the command, and based on the setting value in the command, the sewing machine motor 2a, It is a program which executes sewing based on the sewing pattern data 71a by controlling the operations of the X-axis motor 76a and the Y-axis motor 77a.

(Explanation of sewing operation)

Hereinafter, sewing control performed by the CPU 73 based on the sewing program 70a will be described according to the flowchart of FIG. 13.

When the ready key for instructing the start of sewing control provided in the operation panel 74 is pressed (step S11), the CPU 73 reads the sewing pattern data 71a (step S12), and displays the display portion of the operation panel 74 (step S12). Control to switch 74b) to the sewing screen is executed (step S13).

And when it detects that the start button of the operation panel 74 which shows that the to-be-sealed material was set to the holding frame 111 by the operator was pressed, CPU73 will lower the holding frame 111 by the presser foot motor 79a. Press the sewing object (step S14). Then, driving of the sewing machine motor 2a is started (step S15).

Then, the main shaft angle is detected by the encoder 2b, and the CPU 73 judges whether or not the angle is to be transferred in the X and Y axis directions of the sewing object (step S16).

As a result, in the case of the transfer angle, the X-axis motor 76a and the Y-axis motor 77a are driven in accordance with the X-direction movement amount and the Y-direction movement amount read from the sewing pattern data 71a to execute the movement operation of the object to be sealed. (Step S17). If it is not the transfer angle, the height control of the center presser foot described later is executed (step S18).

Then, via step S17 or S18, the CPU 73 determines whether the transfer of the object to be finished is completed up to the last needle in the sewing pattern data 71a (step S19), and if it is not completed until the last needle, step S16. To reverse the process. The central presser foot, and the loops of steps S16 to S19 are repeatedly performed every minute time of several msec.

In addition, when the transfer to the final needle is completed, the CPU 73 operates the thread cutting device (not shown) to perform thread cutting, and the presser foot motor 79a raises the holding frame 111 to seal the object. To free up and finish the sewing (step S20).

Next, the control performed by the CPU 73 based on the center presser foot height control program 70b with respect to the center presser foot height control performed in the step S18 will be described based on the flowchart of FIG.

In the height control of the center presser foot, the CPU 73 determines whether the detected main axis angle of the encoder 2b is within the height variable control section K1 (step S31), and when it is within the height variable control section K1, Current control is performed so that the output torque of the center presser foot motor 42 becomes the aforementioned counterclockwise driving torque Tm (step S32).

Then, the main shaft angle obtained by the encoder 2b is obtained, and it is determined whether or not it is the end angle 180 ° of the height variable control section K1 (step S33).

As a result, in the case of the end angle of the height variable control section K1, the encoder 81 detects the angle of the output shaft of the central presser foot motor 42, and controls to designate the detection angle as the command angle. (Step S34). As a result, the central presser foot motor 42 is controlled so that the final axial angle of the height variable control section K1 is maintained when the height is changed from the height variable control section K1 to the second holding control section K3. Then, the control of the center presser foot is terminated.

On the other hand, when the detected main axis angle of the encoder 2b is not inside the height variable control section K1, it means that the present main axis angles are the maintenance control sections K2 and K3. The current control is performed so that the output torque of 42 is a high torque value (holding torque T0) which can also counter the load torque T1 of the tension spring 16 (step S35).

Further, it is determined whether or not the detected main shaft angle of the encoder 2b is 0 degrees, and when the main shaft angle is 0 degrees, the CPU 73 changes the command angle of the center presser foot motor 42 to the origin so that the center presser foot motor 42 ) To return to the home position. Then, the center presser foot height control is terminated.

(Effect of Embodiment)

In the electromagnetic cycle sewing machine 100, in the height variable control section K1 in one rotation of the main shaft, the output torque of the central presser foot motor 42 is controlled to be the drive torque Tm offset from the external torque Tf. Since the center presser foot 29 contacts the upper surface of the object according to the thickness of the object, the center presser foot motor 42 raises the bottom dead center of the links 20 and 22 by the reaction force from the object. Since it is easy to change to a direction, pressurization by the center presser foot 29 with respect to a to-be-sealed material can be almost eliminated. On the other hand, when the shift to the second holding control section K3 is carried out, the final axial angle of the central presser foot motor 42 reached in the height variable control section K1 is maintained, so that the center presser foot 29 passes through the bottom dead center. After that, the bottom dead center height can be maintained, and the object to be pulled down by the sewing needle 108 can be pressed downward to effectively suppress the floating and flapping of the object to be sealed.

Therefore, the height adjustment of the center presser foot 29 can be performed in real time during the execution of sewing, and the thickness of the object to be sewing while relieving the burden of checking the occurrence of the interference between the center presser foot and the object to be sewn beforehand by testing sewing. Sewing can be performed corresponding to the.

Furthermore, the height of the center presser foot 29 can be matched to the thickness of the fabric without contacting the object or the distance to the object to be detected and using a detector for detecting the fabric thickness. The productivity can be improved. In addition, since there is no need to install a detector around the needle bar of the sewing machine 100, the space around the needle bar can be secured as a work space, and at the same time, it is not obstructed to mount other mechanisms or members necessary for sewing around the needle bar. Do not.

In addition, since the electronic cycle sewing machine 100 can arbitrarily set the main axis angles of the start and end of the height variable control section K1 by the operation panel 74, the height can be controlled at an appropriate timing according to the thickness of the workpiece. In this manner, the variable control of the height can be ended at an appropriate timing for suppressing the fluff of the object to be sealed.

In addition, in the electronic cycle sewing machine 100, the control apparatus 1000 controls to return the axial angle of the central presser foot motor 42 to the initial position at the position of the main shaft angle 0 ° before starting the height variable control for each needle. Therefore, when the next needle drop position becomes a low position due to the step as shown in points g and h of FIG. 9, the bottom dead center is corrected upward by the variable control of the previous height, so that the next center presser foot 29 By preventing the situation from touching the to-be-sealed object at the time of descent, the bottom dead center of the center presser foot can be properly updated for each needle, and the injury of the to-be-sealed material can be effectively suppressed.

(Etc)

In addition, the main-axis angles of the start and end of the height variable control section K1, the first holding control section K2, and the second holding control section K3 shown in FIG. 11 are merely examples, and the present invention is limited thereto. no.

For example, the starting main axis angle of the height variable control section K1 may be started immediately after the center presser foot motor 29 is returned to the original position by omitting the first holding control section K2. Furthermore, when the maximum value (for example, the height of H1 of FIG. 11) of the thickness of the to-be-sealed object to be sewn is known, the center presser foot 29 is moved with the center presser foot motor 42 at the origin. It is preferable to set it as the main-axis angle before the main-axis angle which becomes height H1, and just before it.

In addition, the end principal axis angle of the height variable control section K1 is 180 degrees or later, before the main shaft angle at which the sewing object pulled up by the sewing needle 108 starts pressing contact with respect to the central presser foot 29. It is desirable to.

Further, the starting main axis angle of the second holding control section K3 is the same as the ending main axis angle of the height variable control section K1.

The main spindle angle of the end of the second holding control section K3 and the main shaft angle of returning the center presser foot motor 29 to the origin are the main shaft angles at which the sewing needle 108 is pulled out of the sewing object. If the sewing needle 108 is not completely out of the state, but the sewing needle 108 indicates the state of escaping from the state in which the object is pulled upward), it may be another angle after the main axis angle, and the main axis angle is not yet known, or In all cases in which it is already known, the end of the first main control angle of the height variable control section K1 may be the end main axis angle and the main axis angle to return to the origin.

Further, the control for returning the axial angle of the center presser foot motor 29 to the origin is not limited to the case of performing instantaneously, and may be gradually returned to the origin until the variable control of the height is started.

In addition, although the drive torque Tm of the center presser foot motor 42 in the height variable control section K1 was described in the opposite direction to the external torque Tf attributable to the pressure spring 30, the pressure spring ( There is also a central presser foot Shanghai East Organization (M1) that does not exist. In this case, in the height variable control section K1, in order to balance the external torque acting clockwise to the output shaft of the central presser foot motor 42 due to the self-weight of the central presser foot 29 or the like. It is preferable to control the center presser foot motor 42 to output the clockwise driving torque.

1 is a perspective view showing a sewing machine according to the present invention.

2 is an enlarged perspective view showing the vicinity of the holding frame of the sewing machine and the center presser foot.

3 is a side view showing the center presser foot device of the sewing machine.

4 is an exploded perspective view of the center presser foot device.

5 is an exploded perspective view of the center presser foot device.

FIG. 6 is an explanatory diagram of height adjustment of the center presser foot of the center presser foot device, and FIG. 6 (a) shows a case where the bottom dead center is adjusted downward, and FIG. 6 (b) shows a case where the bottom dead center is adjusted to abut. .

7 is a block diagram showing a control device of the sewing machine according to the present invention.

8 is an explanatory diagram showing a data configuration of sewing pattern data.

9 is a diagram showing the height change occurring in the center presser foot in which the shank movement and height adjustment are performed by the center presser foot shankdong mechanism and the center presser foot height adjusting mechanism with respect to the change of the main shaft angle according to the rotational driving (upper view). And a leading surface (lower diagram) showing a change in the axial angle of the central presser foot motor 42 controlled by the CPU 73.

FIG. 10 (A) is a point bc section of FIG. 9, FIG. 10 (B) is a point c of FIG. 9, FIG. 10 (C) is a point cd section of FIG. 9, and FIG. 10 (D) is a point e of FIG. FIG. 10 (E) is a schematic diagram showing an operating state of the center presser foot height adjustment mechanism at each main shaft angle of point f in FIG. 9.

Fig. 11 is an explanatory diagram showing a relationship between the main axis angle and the type of control of the central presser foot motor performed by the CPU.

It is a schematic diagram for demonstrating the torque load which the pressurizing spring of a center presser foot height adjustment mechanism brings to a center presser foot motor.

Fig. 13 is a flowchart showing operation control in sewing of the sewing machine according to the present invention.

14 is a flowchart showing processing in the center presser foot height control of the sewing machine according to the present invention.

              Explanation of symbols on the main parts of the drawings

1: center presser foot device 2: spindle

2a: sewing machine motor 2b: encoder (spindle angle detecting means)

16: tension spring 20: third link

22: 4th Link 29: Center Presser Foot

30: pressure spring 33: square piece (operation transmission member)

34: guide member (operation transfer member) 70a: sewing program

70b: center presser foot height control program 73: CPU

74: operation panel (section setting means) 81: encoder (motor shaft angle detection means)

100: electronic cycle sewing machine 110: needle plate

1000: control device (sewing pattern setting means, center presser foot height switching means)

M1: center presser foot Shanghai East mechanism M2: pressurization mechanism

M3: center presser foot retraction mechanism M4: center presser foot height adjusting mechanism

T0: Holding torque Tf: External torque

Tm: Drive torque

Claims (5)

A frame-shaped cloth holding member for holding the cloth, A needle shangdong mechanism for rotating the main needle by rotating the main shaft by a sewing machine motor; Moving means for moving the cloth holding member to move the sewing needle within the frame of the cloth holding member; A center presser foot which contacts the to-be-sealed material to prevent injury of the to-be-sealed material during sewing; A central presser foot shandong mechanism for driving power from the sewing machine motor to move the center presser foot in synchronism with the shangdong of the sewing needle; It has a center presser foot motor, changes the bottom dead center height of the center presser foot to an arbitrary height by changing the rotation angle of the center presser foot motor to an arbitrary angle, and gives the center presser foot motor a holding torque for maintaining the rotation angle. A sewing machine provided with a center presser foot height adjustment mechanism for maintaining the bottom dead center height of a presser foot, The section from the start of lowering or the lowering of the center presser foot to the bottom dead center is controlled so as not to generate rotation of the output shaft of the center presser foot motor as a balanced output with respect to the torque of receiving the torque of the center presser foot motor from the outside. During the lowering of the center presser foot, the angle of the output shaft of the center presser foot motor is changed based on the reaction force received by the center presser foot from the to-be-sealed object by the contact with the to-be-sealed object, whereby the center presser foot is Performs a variable control of the height to stop at a height corresponding to the thickness, In the section from the bottom dead center of the center presser foot to the next start of the descent or during the descent, the maintenance control of the height giving the holding torque to the center presser foot motor to maintain the center presser foot at a height corresponding to the thickness of the sewing material To perform, the sewing machine characterized in that it comprises a center presser foot height control means. The method of claim 1, And a section setting means for setting a main shaft angle at which the section for performing the variable control of the height is started. The method according to claim 1 or 2, The center presser foot height control means controls the center presser foot motor to return the bottom dead center height of the center presser foot to a constant height at the position where the center presser foot rises above the sewing object in every needle in the maintenance control of the height. Sewing machine. The method according to claim 1 or 2, Motor shaft angle detection means for detecting a rotation angle of the output shaft of the central presser foot motor, The center presser foot height control means, in the maintenance control of the height, maintains the rotation angle of the output shaft of the center presser foot motor detected by the motor shaft angle detection means when the variable control of the height ends. Sewing machine, characterized in that for controlling. The method of claim 1, Motor shaft angle detection means for detecting the rotation angle of the output shaft of the central presser foot motor, The center presser foot height control means controls the torque of the center presser foot motor to the holding torque so as to hold the center presser foot at a height corresponding to the rotation angle detected by the motor shaft angle detecting means in the holding control of the height. A sewing machine characterized by returning.

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