JP2020081298A - sewing machine - Google Patents

Abstract

To achieve simplification of a device constitution.SOLUTION: A sewing machine 100 includes: a needle vertical movement mechanism for vertically moving a sewing needle 108; an inner presser foot vertical movement mechanism M1 for vertically moving an inner presser foot 29; and an inner presser foot height adjustment mechanism M4 for adjusting the height of an entire operation range of the vertical movement of the inner presser foot. The sewing machine includes a control device 120 which controls the inner presser foot height adjustment mechanism in such a manner that, before the sewing needle starts plunging into a needle hole 112 of a needle plate 110 in a needle location of a first stitch at the start of sewing, the presser foot descends to the height for pressing an object C to be sewn on the needle plate, and the pressing state by the inner presser foot is maintained at least until the sewing needle goes out of the needle hole.SELECTED DRAWING: Figure 9

Description

The present invention relates to a sewing machine having a center presser.

2. Description of the Related Art There is a sewing machine having an inner presser capable of loosely inserting a sewing needle in place of a cloth presser which presses a material to be sewn on a needle plate from above with a certain elastic force.
The intermediate presser is supported at a height that does not reach the needle plate so as not to press too much on the sewn item, moves up and down with a stroke smaller than the sewing needle, presses the fluttering of the sewn item, and raises the sewing needle. Can be pulled out smoothly from the article to be sewn (see, for example, Patent Document 1).

JP, 2006-109922, A

In the sewing machine having the center presser as described above, the center presser vertical movement mechanism for performing the vertical movement operation of the center presser and the center presser height adjustment mechanism for adjusting the height of the entire operation range of the center presser vertical movement are provided. However, since the device configuration and control system of the sewing machine are complicated and the number of parts is increased, it has been desired to simplify the machine configuration.

An object of the present invention is to simplify the mechanical structure.

The invention according to claim 1 is a sewing machine,
A needle up-and-down mechanism that moves the sewing needle up and down,
An intermediate press up/down moving mechanism that moves the intermediate press up and down,
In a sewing machine including an intermediate presser height adjusting mechanism for adjusting the height of the entire vertical movement range of the intermediate presser,
Before the sewing needle starts to plunge into the needle hole of the needle plate at the needle drop of the first stitch at the start of sewing, the intermediate presser descends to a height for pressing the workpiece on the needle plate, and at least the needle A control device for controlling the intermediate presser height adjusting mechanism is maintained so that the pressing state by the intermediate presser is maintained until the sewing needle comes out from the hole.

The invention according to claim 2 is the sewing machine according to claim 1,
The control device controls the middle presser height adjusting mechanism so as to maintain the pressing state by the middle presser until the sewing needle after the needle drop of the first stitch reaches the top dead center thereof. And

The invention according to claim 3 is the sewing machine according to claim 1,
Equipped with a moving mechanism that moves the workpiece by holding it with a holding frame.
The control device controls the middle presser height adjusting mechanism so as to release the pressing state by the middle presser before the movement of the holding frame to the needle drop position of the second stitch starts.

The invention according to claim 4 is a sewing machine,
A needle up-and-down mechanism that moves the sewing needle up and down,
An intermediate press up/down moving mechanism that moves the intermediate press up and down,
An intermediate presser height adjusting mechanism for adjusting the height of the entire vertical movement range of the intermediate presser,
In a sewing machine including a thread cutting device for cutting a sewing thread,
By the time the moving knife of the thread trimming device executes cutting, the inner presser is lowered to a height at which the sewing target is pressed onto the needle plate, and at least until the thread trimming device completes cutting of the sewing thread. It is characterized by comprising a control device for controlling the intermediate presser height adjusting mechanism so as to maintain the pressing state by the intermediate presser.

The invention according to claim 5 is the sewing machine according to claim 4,
The control device is
The intermediate presser descends to a height at which the sewing workpiece is pressed onto the needle plate before the sewing needle that starts moving immediately before the cutting operation of the thread cutting device starts cutting operation and the sewing needle starts to rise from the bottom dead center. As described above, the middle presser height adjusting mechanism is controlled.

According to the present invention, since the intermediate presser holds the sewing start end portion of the sewing thread, it is possible to eliminate the thread gripping mechanism conventionally mounted on the sewing machine, simplify the device configuration, and simplify the control system. Can be realized. In addition, along with this, it is possible to reduce the number of parts of the sewing machine, reduce the manufacturing cost accordingly, and downsize the device.

Further, according to another aspect of the present invention, since the intermediate presser shortens the remaining end of the sewing thread, the remaining end processing mechanism conventionally mounted on the sewing machine can be omitted, and the device configuration can be simplified and controlled. It is possible to realize simplification of the system. In addition, along with this, it is possible to reduce the number of parts of the sewing machine, reduce the manufacturing cost accordingly, and downsize the device.

It is a perspective view showing a sewing machine concerning the present invention. FIG. 6 is an enlarged perspective view showing the vicinity of a holding frame and an inner presser of the sewing machine. It is a front view of the inside presser device in a sewing machine arm part. FIG. 4 is a front view of the intermediate presser in the sewing machine arm, showing a state in which the intermediate presser is adjusted higher than in FIG. 3. It is an exploded perspective view showing a part of composition of an inside control device. It is an exploded perspective view showing other one part composition of an inside presser device. It is a bottom view of a thread cutting device. It is a block diagram showing a control system of the sewing machine. FIG. 9 is a front view in which a part of the vicinity of the needle drop position is cut away in the intermediate presser height control at the start of sewing. It is the front view which notched a part of needle drop position periphery in middle presser height control at the time of thread cutting execution, FIG.10(A) shows the state before intermediate presser fall, FIG.10(B) is inside. The state after pressing down is shown. 11A is a partially enlarged view of FIG. 10A, and FIG. 11B is a partially enlarged view of FIG. 10B. It is a flow chart which shows the whole operation control at the time of sewing.

[Outline of Embodiment of Invention]
Hereinafter, an embodiment 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.
FIG. 1 is a perspective view of the sewing machine 100, and FIG. 2 is an enlarged perspective view around a sewing needle.
The electronic cycle sewing machine has a holding frame that holds a plurality of objects to be sewn, and the sewing is performed while the holding frame moves relative to the sewing needle, thereby holding a plurality of holding frames. It is a sewing machine that forms a seam on a material to be sewn based on predetermined sewing data.
Here, a direction in which the sewing needle 108, which will be described later, moves up and down is defined as a Z-axis direction (vertical direction), and a predetermined direction orthogonal thereto is defined as an X-axis direction (horizontal direction), and both the Z-axis direction and the X-axis direction are defined. The direction orthogonal to is defined as the Y-axis direction (front-back 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 an upper surface of a sewing machine table T and a lower portion of the sewing machine table T for operating the sewing machine main body 101. A pedal R and a portable operation panel 300 for performing an input operation by a user are provided.

[Sewing machine 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 forms an upper portion of the sewing machine main body 101 and extends in the Y-axis direction. A sewing machine arm 102a forms the lower portion of the sewing machine main body 101 and extends in the Y-axis direction. It has a standing body portion 102c that connects the bed portion 102b.
The sewing machine main body 101 has a power transmission mechanism arranged in a sewing machine frame 102 and has a main shaft and a lower shaft (both not shown) that are rotatable and extend in the Y-axis direction. The main shaft is rotatably supported inside the sewing machine arm portion 102a, and the lower shaft (not shown) is rotatably supported inside the sewing machine bed portion 102b.

The main shaft is connected to the sewing machine motor 2a (see FIG. 7), and a rotational force is applied by the sewing machine motor 2a. The lower shaft (not shown) is connected to the main shaft via a timing belt and a pulley (not shown). When the main shaft rotates, the power of the main shaft is transmitted to the lower shaft side via the timing belt and the pulley. , The lower shaft rotates at double speed of the main shaft.

A shuttle device (not shown) is provided at the front end of the lower shaft (not shown). When the lower shaft rotates together with the main shaft, the stitches are formed by the cooperation of the sewing needle 108 and the outer hook (not shown) of the hook device.
The shuttle device includes an outer hook fixedly mounted on the front end portion of the lower shaft, and an inner hook holding a bobbin inside the outer hook. The structure of the shuttle device is similar to that of a known device, and will not be described in detail here.

[Needle up/down mechanism]
A needle bar 108a holding a sewing needle 108 at the lower end is supported at the front end of the sewing machine arm 102a so as to be vertically movable. Inside the front end portion of the sewing machine arm portion 102a, a needle bar crank fixedly mounted on the front end of the main shaft, a needle bar hanger fixedly mounted on the needle bar 108a, and a crank rod connecting the needle bar crank and the needle bar hanger are provided. It is provided.

The needle bar crank rotates together with the main shaft. One end of the crank rod is connected to the rotation circumference of the needle bar crank so as to be rotatable about the Y axis, and the other end is connected to the needle bar holder about the Y axis. Therefore, when the main shaft is rotated by the sewing machine motor 2a, one end of the crank rod makes a revolving motion, and only the vertical motion, which is the Z-axis component of the revolving motion, is transmitted to the other end, causing the needle bar 108a to move up and down. Can be granted.
That is, the sewing machine motor 2a, the main shaft, the needle bar crank, the needle bar holder, the crank rod, and the needle bar 108a constitute a needle vertical movement mechanism for moving the sewing needle 108 up and down.
Since the needle up-and-down moving mechanism has the same structure as the known structure, the illustration of each structure is omitted.

[Movement mechanism]
As shown in FIGS. 1 and 2, a needle plate 110 is arranged on the sewing machine bed portion 102b, and a holding frame 111 as a cloth holding portion is arranged above the needle plate 110.
The holding frame 111 is attached to a mounting member 113 arranged below the sewing machine arm portion 102a, and the mounting member 113 has an X-axis motor via a belt mechanism (not shown) arranged in the sewing machine bed portion 102b. 76a and Y-axis motor 77a are connected (see FIG. 7).
The holding frame 111 holds the sewn object, and moves the held sewn object in the front-rear, left-right direction 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 needle drop are interlocked with each other, so that the stitches based on the plurality of needle drop positions recorded in the predetermined sewing data are formed on the workpiece.

The holding frame 111 includes a cloth presser and a lower plate.
Further, the attachment member 113 supports the cloth presser of the holding frame 111 so as to be able to move up and down, and imparts a lifting operation to the cloth presser by driving the cloth presser motor 79a arranged in the sewing machine arm portion 102a. The cloth retainer is adapted to clamp and hold the article to be sewn between the cloth retainer and the lower plate when the cloth retainer is moved downward.
Then, the holding frame 111, the mounting member 113, the belt mechanism, the X-axis motor 76a, the Y-axis motor 77a, the cloth pressing motor 79a, and the like arbitrarily move and position the sewing object along the X-axis direction and the Y-axis direction. Functions as a moving mechanism.

[pedal]
The pedal R performs an input operation for driving the sewing machine 100, moving the needle bar 108a and the sewing needle 108 up and down, and operating the holding frame 111.
The pedal R has a built-in sensor for detecting the depression operation position of the pedal R, and an output signal from the sensor is input to the control device 120 described later as an operation signal of the pedal R.
The control device 120 controls the driving of the sewing machine 100 and other operations by an operation signal corresponding to the operation position.

[control panel]
Further, the sewing machine 100 is provided with an operation panel 300 for performing an operation input by a user, and various data and operation signals input to the operation panel 300 are input to a control device 120 described later.
The operation panel 300 includes a display unit 300b including a liquid crystal display panel and a touch sensor 300c provided on a display screen of the display unit 300b, and various operation keys displayed on the liquid crystal display panel. By touching the touch panel or the like, a position where the touch panel is touched is detected, and an operation signal corresponding to the detected position is output to the control device 120 described later.

[Center presser]
3 and 4 are front views of the middle presser device 1 in the sewing machine arm portion 102a, FIG. 5 is an exploded perspective view showing a part of the structure of the middle presser device 1, and FIG. It is an exploded perspective view showing composition.
The intermediate presser device 1 moves up and down in conjunction with the vertical movement of the needle bar 108a at the front end of the sewing machine arm portion 102a in order to prevent the sewing needle 108 from being lifted up and down due to the vertical movement of the sewing needle 108. It has an inner presser 29 which suppresses the flapping of the material to be sewn around. The main body of the middle presser device 1 is arranged inside the sewing machine arm portion 102a, and the middle presser 29 is arranged below the front end portion of the sewing machine arm portion 102a. The center presser 29 has a circular frame, and the sewing needle 108 is loosely inserted inside.

As shown in FIGS. 3 to 6, the intermediate presser device 1 includes an intermediate presser 29, an intermediate presser up-and-down moving mechanism M1 for vertically moving the intermediate presser 29 synchronously with a sewing needle 108 which moves up and down by rotation of a main shaft, An overload avoidance mechanism M2 that enables an escape operation for avoiding an overload on the intermediate presser vertical movement mechanism M1 when the lowering operation of the intermediate presser 29 is obstructed, an intermediate presser retracting mechanism M3 that raises the intermediate presser 29 to a retracted position, and a sewing machine. An intermediate presser height adjusting mechanism M4 for adjusting the height of the entire vertical movement range of the intermediate presser 29 by the motor 2a is provided.

[Center presser: Center press vertical movement mechanism]
The center presser vertical movement mechanism M1 obtains the power of the vertical movement of the center presser 29 from the rotation of the main shaft of the needle vertical movement mechanism.
That is, the center presser vertical movement mechanism M1 includes an eccentric cam provided on the main shaft, a connecting rod that rotatably holds the eccentric cam at one end, and a swing shaft 6 that reciprocally rotates along the Y-axis direction. A reciprocating mechanism including a swing arm extending from the swing shaft 6 in the Z-axis direction is provided.
The other end of the connecting rod is connected to the rotating end of the swing arm so as to be rotatable about the Y axis. As a result, when the main shaft makes a full rotation, the eccentric cam causes one end of the connecting rod to rotate around the Y axis, and the other end moves forward along the X axis direction. Then, the forward movement along the X-axis direction is also transmitted to the rotating end portion of the swing arm, and the swing shaft 6 that pivotally supports the swing arm reciprocally rotates in the same cycle as the rotation of the main shaft.
Since the reciprocating mechanism using the eccentric cam is a well-known mechanism, the illustration of each component except the swing shaft 6 is omitted.

Further, as shown in FIG. 6, the base end portion of the middle presser adjusting arm 7 for adjusting the amount of movement of the middle presser 29 in the vertical direction D1 is fixed to the other end of the swing shaft 6. A cam groove 7a is formed in the middle presser adjusting arm 7. The cam groove 7a is an arc-shaped long hole, and the upper end of the first link 8 is pivotally supported around the Y axis by an adjusting nut 9 and a step screw 10 at a desired position of the cam groove 7a. The fixed position of the upper end portion of the first link 8 can be adjusted to move toward and away from the center of the swing shaft 6, and the amount of reciprocating motion given to the first link 8 according to the distance from the center, that is, the middle presser The vertical movement amount of 29 can be increased or decreased.

As shown in FIG. 6, the lower end of the first link 8 is connected to a substantially intermediate portion in the longitudinal direction of the second link 11 by a step screw 12 so as to be rotatable about the Y axis. Here, the cam groove 7a with which the adjusting nut 9 engages is formed so as to be a part of an arc centered on the axial center of the step screw 12 when the center presser 29 is at the bottom dead center of the vertical reciprocating motion. Has been done. That is, by adjusting the position of the first link 8 in the cam groove 7a, it is possible to adjust the stroke while keeping the bottom dead center position of the middle presser 29 immovable.

The left end of the second link 11 is pivotally supported around the Y axis by a step screw 18 with respect to a positioning link 13 described later.
The right end of the second link 11 is connected to the upper end of the third link 20 by a step screw 21 so as to be rotatable around the Y axis, as shown in FIG. An upper end of the fourth link 22 is connected to a lower end of the third link 20 by a step screw 23 so as to be rotatable about the Y axis.

A link relay plate 25 is connected to the lower end of the fourth link 22 around the Y axis by a step screw 26. An intermediate presser bar hanger 27 is fixed to the link relay plate 25, and an intermediate presser bar 28 extending in the Z-axis direction is held by the intermediate presser bar hanger 27. An intermediate presser 29 is attached to the lower end of the intermediate presser bar 28 to suppress the rise of the material to be sewn during sewing.
A pressing spring 30 supported by the bolt 31, the nut 32, and the spring support shaft 301 is provided on the upper side of the center pressing rod 28, and the center pressing rod 28 and the center pressing 29 are constantly moved downward by the pressing spring 30. Pressed.

Further, in the present embodiment, the reciprocating mechanism, the swing shaft 6, the middle presser adjusting arm 7, the first link 8, the second link 11, the third link 20, the fourth link 22, the middle presser bar holder 27, the middle presser. The rod 28, the pressing spring 30, the bolt 31, the nut 32, the step screw 37, and the like constitute an intermediate pressing vertical movement mechanism M1.

[Intermediate presser device: Intermediate presser height adjustment mechanism]
The middle presser height adjustment mechanism M4 adjusts the height of the bottom dead center of the middle presser 29, thereby adjusting the height of the entire vertical movement range of the middle presser 29 by the sewing machine motor 2a.

The stepped screw 23 described above, together with the square piece 33 and the guide member 34, connects the third link 20 and the fourth link 22. That is, the guide member 34 is provided on the front side of the fourth link 22, and the square piece 33 is slidably supported along the longitudinal direction of the guide member 34.

The upper end portion 34t of the guide member 34 is supported by the step screw 35 so as to be rotatable around the Y axis around the Y axis with the longitudinal direction substantially along the Z axis direction. Therefore, the lower end of the guide member 34 swings left and right, and the longitudinal direction of the guide member 34 can be tilted left and right.
An elongated hole 34a is formed in the vicinity of the lower end of the guide member 34 along the longitudinal direction thereof. The rectangular piece 33 is slidably fitted inside the long hole 34a. Therefore, the guide member 34 can move the connecting portion of the third link 20 and the fourth link 22 along the long hole 34a via the square piece 33.

Further, as shown in FIG. 6, in the guide member 34, the right end portion of the moving link 36 for swinging the guide member 34 in the X axis direction is rotated around the Y axis by the step screw 37 near the upper portion of the elongated hole 34 a. Is rotatably connected to. An eccentric cam 38 is connected to the left end of the moving link 36, and the eccentric cam 38 is fixedly supported by the front end of the variable shaft 39.
The variable shaft 39 is arranged along the Y-axis direction, and is supported by a bearing 40 so as to be rotatable about the Y-axis, as shown in FIG. Further, a bevel gear 41 is fixedly installed at an intermediate portion of the variable shaft 39, and a driven gear 391 is fixedly mounted at a rear end portion thereof.

On the other hand, behind the variable shaft 39, there is arranged an intermediate presser motor 42 with the output shaft facing forward, and the output shaft is fixedly equipped with a driving gear 421. The main drive gear 421 meshes with the driven gear 391 of the variable shaft 39, and the drive of the center presser motor 42 allows the variable shaft 39 to rotate.

That is, the drive of the center presser motor 42 is transmitted in the order of the variable shaft 39, the eccentric cam 38, and the movement link 36, and the movement link 36 rotates the guide member 34.
The center presser motor 42 can be rotationally driven in the forward and reverse directions, and the rotation amount and drive timing thereof can be controlled by the control device 120.
Further, the center presser motor 42 is provided with an encoder 81 for detecting the shaft angle of its output shaft. The encoder 81 is of a so-called absolute type and can detect the absolute position of the shaft angle of the output shaft, and does not require an origin sensor. The encoder 81 may be an incremental type and may have a origin sensor and a pulse counter.
Then, the center presser motor 42, the main drive gear 421, the driven gear 391, the variable shaft 39, the eccentric cam 38, the movement link 36, the guide member 34, the square piece 33, and the like move the vertical movement range of the center presser 29 by the sewing machine motor 2a. It functions as a middle presser height adjusting mechanism M4 that changes the overall height in the vertical direction.

[Center control device: Overload avoidance mechanism]
As shown in FIG. 6, the above-described positioning link 13 is attached to the sewing machine frame 102 as a sewing machine housing so as to be rotatable around the Y axis by a step screw 14 in the vicinity of the central portion thereof. The position of the step screw 14 viewed from the Y-axis direction is concentric with the position of the step screw 12 when the center presser 29 is at the bottom dead center.

A spring hook 13a is formed at the right end of the positioning link 13, the upper end of the tension spring 16 is connected to the spring hook 13a, and the lower end of the tension spring 16 is fixed to the sewing machine frame 102. It is connected to the hook 15. Therefore, the right end of the positioning link 13 is always under tension.

The positioning link 13 is integrally equipped with a stopper 17 on the rear surface side thereof, and a regulating member 19 is in contact with the stopper 17 above the left end thereof. Therefore, the positioning link 13 is brought into a state in which the left end portion of the positioning link 13 is pressed against the regulating member 19 via the stopper 17 by the downward tension from the tension spring 16 applied to the right end portion thereof, and the positioning screw 13 is centered around the step screw 14. The rotation in the direction is restricted.

As a result, the second link 11 is supported when the height of the intermediate presser 29 is adjusted too low or when the intermediate presser 29 comes into contact with the sewing target when the intermediate presser 29 descends because the thickness of the sewing target is too thick. The right end portion of the positioning link 13 is lifted up against the tension spring 16 and the downward pressing force applied to the second link 11 from the first link 8 can be released.
In other words, the tension spring 16, the spring hook 15, the stopper 17, the positioning link 13, the regulating member 19 and the like allow an escape operation for avoiding an excessive load with respect to the intermediate presser vertical movement mechanism M1 when the downward movement of the intermediate presser 29 is obstructed. It functions as the load avoidance mechanism M2.

[Center presser: Center press retract mechanism]
As shown in FIG. 5, a bevel gear 43 is meshed with a bevel gear 41 provided on the variable shaft 39 described above, and drives the center presser motor 42 in a direction D4 orthogonal to the axial direction of the variable shaft 39. It is possible to output in the rotation direction centering around. On the right side of the bevel gear 43, a bearing 44, a center press lifting cam 45, etc. are coaxially connected along the X-axis direction.

The center press lifting cam 45 is an outer peripheral cam. The outer circumference of the center press lifting cam 45 has a constant outer diameter in the range of 180° around the axis (hereinafter referred to as a maintenance portion), and the remaining part of the angular range has a shape in which the outer diameter gradually increases (hereinafter referred to as a changed portion). ).
The center presser lifting cam 45 vertically moves one end portion 46a of the center presser lifting member 46 that raises the center presser 29 to the retracted position after sewing is completed. A cylindrical roller 47 provided on the upper end portion of the lever member 461 along the Z-axis direction for rotating the middle press-up member 46 makes sliding contact.

The lever member 461 is pivotally supported by a pin 462 at an intermediate portion in the Z axis direction and is rotatable about the X axis.
The lower end of the lever member 461 is connected to the rear end of the transmission link 463 along the Y-axis direction so as to be rotatable about the X-axis.
Further, a rear end portion of a tension spring 464 that applies tension to the front is connected to the vicinity of the lower end portion of the lever member 461, whereby the roller 47 of the upper end portion of the lever member 461 is pressed by the center presser lifting cam 45. It is pressed against the outer circumference.

The center press-up member 46 has a substantially L shape when viewed from the X-axis direction, is pivotally supported by the pin 48 at the bent portion, and is rotatable about the X-axis.
One end portion 46a of the intermediate presser raising member 46 that raises the intermediate presser 29 by locking the link relay plate 25 (see FIG. 6) from below extends forward from the bent portion. The other end 46b of the middle press-up member 46 extending upward from the bent portion is connected to the front end of the transmission link 463 so as to be rotatable about the X axis.

With the above configuration, when the middle presser motor 42 is driven, the middle presser elevating cam 45 is rotated, and when the roller 47 is in sliding contact with the maintaining portion of the middle presser elevating cam 45, the middle presser height adjusting mechanism M4 The height of the entire vertical movement range of the presser 29 is changed in the vertical direction. Then, when the roller 47 is in sliding contact with the changed portion of the center presser lifting cam 45, the lower end of the lever member 461 rotates rearward against the tension spring 464 and raises the center presser via the transmission link 463. The member 46 is urged to rotate in the clockwise direction, and the one end portion 46a pulls up the center presser 29 to the upper retracted position.
That is, the bevel gears 41 and 43, the intermediate presser elevating cam 45, the roller 47, the lever member 461, the transmission link 463, the tension spring 464, the intermediate presser raising member 46, and the like constitute an intermediate presser retracting mechanism M3.

[Movement of center press during sewing]
Next, the operation of the middle presser up-and-down moving mechanism M1 having the above structure will be described.
When the main shaft is rotated by the driving of the sewing machine motor 2a, the swing shaft 6 is reciprocally rotated by the reciprocating mechanism. As a result, the middle presser adjusting arm 7 swings up and down, and the right end of the second link 11 swings in the series direction D2 of the third link 20 and the fourth link 22 via the first link 8, The third link 20 and the fourth link 22 swing in the series direction (vertical direction) D2. Along with this, the intermediate presser bar 28 moves vertically along the vertical direction D1, so that the intermediate presser 29 moves upward and downward in synchronization with the vertical movement of the sewing needle 108.

[Adjusting the height of the center presser with the center presser]
Next, an operation of adjusting the height of the intermediate presser 29 by the intermediate presser height adjusting mechanism M4 having the above-described structure will be described.
The drive of the center presser motor 42 is transmitted to the variable shaft 39 via the main driving gear 421 and the driven gear 391, the variable shaft 39 and the eccentric cam 38 rotate, and the guide member 34 swings substantially along the X-axis direction. Move. As a result, the bending angle of the third link 20 and the fourth link 22 changes at the connecting portion via the square piece 33, and the height of the center presser 29 changes. At this time, since the square piece 33 moves up and down along the long hole 34a of the guide member 34, the center presser 29 moves up and down, and the height of the entire vertical movement range of the center presser 29 varies. .. Therefore, the height of the bottom dead center in the vertical movement of the intermediate presser 29 can be adjusted by the intermediate presser height adjusting mechanism M4. That is, it is possible to adjust the height of the entire vertical movement range of the center presser 29.

[Thread trimmer]
FIG. 7 shows a bottom view of the thread cutting device 90.
The thread trimming device 90 includes a moving knife 91 that rotates about the Z axis, a fixed knife 92 that cooperates with the moving knife 91 to cut an upper thread and a lower thread as a sewing thread, and the moving knife 91 rotates. A thread trimming motor 96 (see FIG. 8) as an actuator serving as a driving source for the operation, and a plurality of link bodies 93 to 95 for transmitting reciprocal rotation from the thread trimming motor 96 to the moving knife 91 are provided.

The moving knife 91 cuts the sewing end ends of the upper thread and the lower thread by reciprocating rotation by forward and backward movements.
That is, the moving knife 91 is on standby at the position P1 when it is not used, and after making the forward turn from the position P1 to the position P2, it makes the reverse pass from the position P2 to the position P1 and the upper thread and Cut the end of sewing the lower thread.

It should be noted that after the last needle drop at the end of sewing, the upper thread and the lower thread hang down from the needle hole 112 of the needle plate 110. At this time, since the upper thread is pulled out in a loop by the sword tip of the outer hook, the portion of the upper thread on the side of the sewing needle 108 and the portion on the side of the fabric hang down under the needle hole 112.
Since the thread trimming device 90 needs to cut only the cloth-side portion of the upper thread on the side of the sewing needle 108 and the cloth-side portion and the lower thread, the reciprocating forward and backward rotation of the moving knife 91. Occasionally, threading work is performed to select a portion of the upper thread on the sewing needle 108 side (non-cutting portion), a portion of the upper thread on the fabric side (cutting portion), and a bobbin thread. Cut the fabric side of the thread and the bobbin thread.

Therefore, the moving knife 91 is provided at the downstream side (rear side) side edge portion in the forward rotation direction with a thread separating section 911 for selecting a portion of the upper thread on the sewing needle side, a portion on the fabric side and a lower thread. In addition, a concave catching portion 913 that catches the cloth-side portion of the upper thread and the lower thread and carries them to the fixed knife 92 is provided at the side edge portion on the downstream side (front side) in the backward rotation direction.
Furthermore, a through hole 914 is formed between the thread handling section 911 and the catching section 913, and a blade section 912 is formed at the rear inner edge of the through hole 914.

The thread handling section 911 is formed in a sharp shape toward the rear side, and is formed at a position which passes directly below the needle hole 112 when the moving knife 91 rotates forward. The tip end of the thread handling section 911 radially extends the upper thread hanging needle 108 side portion, the upper thread sewing needle 108 side portion, and the workpiece side portion and the lower thread portion. A portion of the upper thread on the side to be sewn and a lower thread are radially selected to the outside.

The portion of the upper thread on the sewn side of the upper thread and the lower thread, which are selected in the radial direction by the thread separating section 911, follow the outer edge of the moving knife 91 to the capturing section 913 and are captured by the capturing section 913. It
Then, when the catching portion 913 passes through the cutting edge 921 of the fixed knife when the moving knife 91 is rotated in the backward direction, a cloth-side portion of the upper thread and the lower thread are provided between the upper surface of the moving knife 91 and the lower surface of the fixed knife 92. It becomes a state where and are sandwiched.
Then, when the moving knife 91 continues to rotate further, the cloth-side portion of the upper thread sandwiched between the upper surface of the moving knife 91 and the lower surface of the fixed knife 92 and the lower thread are pushed into the through hole 914. When the blade portion 912 enters and the blade edge of the fixed knife 92 passes each other, the cloth-side portion of the upper thread and the lower thread are cut.

[Wiper device]
In the vicinity of the front end of the sewing machine arm 102a, a wiper mechanism for pulling the upper thread end of the sewing needle 108 side after thread cutting at the end of sewing from the lower side to the upper side of the workpiece is provided.
Since the wiper mechanism is a well-known structure, although not shown in the drawings, a wiper member that horizontally displaces the upper thread between the lower end of the sewing needle 108 and the intermediate presser 29 at the upper stop position, and the wiper member removes the upper thread. The wiper solenoid 82 (see FIG. 8) is provided as a drive source that imparts a turning motion for removing.

[Sewing machine control system: controller]
FIG. 8 is a block diagram showing the control system of the sewing machine 100.
The sewing machine 100 includes a control device 120 as an operation control unit for controlling the operation of each of the above-mentioned units. Then, the control device 120 includes a program memory 70 in which various control programs 70a are stored, a data memory 71 as a storage unit that stores sewing data 71a and various setting information (not shown), and the program memory 70. A CPU 73 for executing each program 70a is provided.

Further, the CPU 73 is connected to the operation panel 300 via the interface 300a. The operation panel 300 includes a display unit 300b that displays various screens and input buttons and a touch sensor 300c that is provided on the surface of the display unit 300b and detects the contact position of the display unit 300b, and functions as an input/output unit for various information. To do. All of the input buttons and input switches used in the operation panel 300 are displayed on the display unit 300b, and when the input is detected by the touch sensor 300c, they function in the same manner as push-down buttons and switches.
The operation panel 300 also has a function of arbitrarily setting a setting parameter of the sewing data 71a and a function of selecting desired data from a plurality of sewing data 71a.

Further, the CPU 73 is connected via an interface 75 to a sewing machine motor drive circuit 75b that drives the sewing machine motor 2a, and controls the rotation of the sewing machine motor 2a. The sewing machine motor 2a includes an encoder 2b.
A servo motor, for example, can be applied to the sewing machine motor 2a.

Further, the CPU 73 is connected via an interface 76 and an interface 77 to an X-axis motor drive circuit 76b and a Y-axis motor drive circuit 77b for driving the X-axis motor 76a and the Y-axis motor 77a of the moving mechanism, respectively, and the holding frame 111. Control the movement of the X-axis direction and the Y-axis direction.

Further, the CPU 73 is connected via an interface 78 to an intermediate presser motor drive circuit 78b for driving the intermediate presser motor 42 that adjusts the bottom dead center height position of the vertical movement of the intermediate presser 29a by the sewing machine motor 2a. Control the operation of the device 1. As described above, the output shaft of the intermediate presser motor 42 is provided with the encoder 81 as a motor shaft angle detecting means.

Further, the CPU 73 is connected to a cloth presser motor drive circuit 79b for driving a cloth presser motor 79a which moves a cloth presser (not shown) up and down via the interface 79, and controls the operation of the cloth presser.
Further, the CPU 73 is connected to a thread cutting motor drive circuit 96b for driving the thread cutting motor 96 via the interface 96c, and controls the operation of the thread cutting device 90.
A stepping motor, for example, can be applied to the X-axis motor 76a and the Y-axis motor 77a, the intermediate presser motor 42, the cloth presser motor 79a, and the thread cutting motor 96.
Further, the CPU 73 is connected via an interface 82c to a solenoid drive circuit 82b for driving a wiper solenoid 82 for rotating the wiper member, and controls the yarn wiping operation by the wiper member.

[Data memory]
The data memory 71 stores sewing data 71a. The sewing data 71a is data for performing sewing according to a series of sewing patterns.
That is, in the sewing data 71a, position coordinate data of a plurality of needle drop positions along the sewing pattern, set values of the intermediate presser height, commands such as thread trimming, and the like are recorded in the order of execution.

Further, the data memory 71 also stores table data and the like indicating the correspondence between the axial angle of the intermediate presser motor 42 and the height of the bottom dead center of the intermediate presser 29. When controlling the height of the intermediate presser 29, the CPU 73 refers to the table data from the set value of the bottom dead center height of the intermediate presser, determines the axial angle of the intermediate presser motor 42, and performs control.

[Intermediate presser height control at the start of sewing]
The CPU 73 of the control device 120 of the sewing machine 100 executes the intermediate presser height control at the start of sewing based on the control program 70a in the program memory 70.
In this intermediate presser height control at the start of sewing, the CPU 73 causes the intermediate presser 29 to be placed on the throat plate 110 before the sewing needle 108 starts to plunge into the needle hole 112 at the needle drop of the first stitch at the start of sewing. The intermediate presser motor 42 for controlling the intermediate presser height is controlled so that the intermediate presser 29 is lowered to a height at which the material to be sewn is pressed down and the pressed state by the intermediate presser 29 is maintained at least until the sewing needle 108 comes out from the needle hole 112. ..

That is, as shown in FIG. 9, the end portion of the needle thread U initially hung down from the sewing needle 108 through the inside of the intermediate presser 29 and the lowering of the intermediate presser 29 causes the upper surface of the workpiece C and the intermediate presser 29 to be sewn. It is sandwiched between the bottom and.
As a result, at the start of sewing, the end of the upper thread U falls off from the needle drop position of the first stitch of the sewing target C due to the tension generated by the vertical movement of the sewing needle 108, the drawing of the hook, the lifting of the balance, and the like. Suppress it.

In the above-described intermediate presser height control at the start of sewing, "before the sewing needle 108 starts to plunge into the needle hole 112 at the needle drop of the first stitch" means the tip of the sewing needle 108 of the first stitch at the time of sewing. This means that the center presser 29 starts pressing the upper thread U before the section starts to plunge into the needle hole 112.
For example, during the period from the completion of the movement of the holding frame 111 of the moving mechanism to the needle drop position of the first stitch to the start of the leading end of the sewing needle 108 into the needle hole 112, the middle presser 29 is used. You can start pressing at any time.

In the above-described intermediate presser height control at the start of sewing, "at least until the sewing needle 108 comes out of the needle hole 112" means that the tip of the sewing needle 108 that rises after passing through the bottom dead center of the first stitch is the needle. It means that the above-mentioned pressing is continued until the timing when the hole 112 is completely removed.
Since the end of the upper thread U receives tension due to various factors such as the elevation of the sewing needle 108, the pulling in of the hook, and the lifting of the balance, pressing by the center presser 29 until reaching the top dead center where the elevation of the sewing needle 108 stops. It is desirable to continue.
However, in the case of the sewing machine 100 including the moving mechanism, it is more preferable to release the pressing before starting the movement of the holding frame 111 to the needle drop position of the second stitch.

In the intermediate presser control at the start of sewing, the "pressing state by the intermediate presser 29" means that the bottom of the intermediate presser 29 is at the same height as the upper surface of the sewing object on the needle plate 110 or lower than the upper surface. Means that.
However, when the thickness of the material to be sewn is unknown, it is desirable that the bottom portion of the center presser 29 be in a state of being equal to or lower than the upper surface height of the needle plate 110.
Further, since the sewing machine motor 2a is driven from the start to the release of the pressing, the intermediate presser vertical movement mechanism M1 imparts the vertical movement to the intermediate presser 29. Therefore, even when the middle presser adjusting arm 7 of the middle presser vertical movement mechanism M1 pulls up the middle presser 29 to the uppermost position (top dead center of the middle presser 29), the bottom of the middle presser 29 has the upper surface height of the needle plate 110 or It is desirable that the intermediate presser 29 be sufficiently lowered to a height that reaches the height of the upper surface of the workpiece.
In particular, the middle presser adjusting arm 7 of the middle presser vertical movement mechanism M1 can adjust the connecting position of the upper end portion of the first link 8 by the cam groove 7a, and is located farthest from the center of rotation of the middle presser adjusting arm 7. When the upper ends of the 1-links 8 are connected, the center presser 29 has the highest top dead center position. Therefore, in consideration of this, even when the top dead center position of the center presser 29 is the highest, the bottom presser of the center presser 29 reaches the height of the top surface of the needle plate 110 or the top surface of the sewing object. It is more desirable to lower 29 sufficiently.
Then, when the pressing state is released by the intermediate presser 29, the intermediate presser motor 42 is controlled so that the intermediate presser height set value set in the sewing data 71a becomes the set value.

As described above, in the sewing machine 100, after cutting the sewing thread at the end of sewing, the upper thread U is wiped by the wiper member between the sewing needle 108 and the intermediate presser 29, and the sewing after the upper thread U is cut. A wiper mechanism for pulling out the end portion on the side of the needle 108 to the upper side of the workpiece C is provided.
When performing the sewing by performing the intermediate presser height control at the start of sewing described above, it is possible to restrict the thread wiping operation by the wiper mechanism after cutting the sewing thread at the sewing end of the previous sewing. desirable.
That is, since the wiper mechanism performs thread wiping between the lower end portion of the sewing needle 108 and the intermediate presser 29, the sewing start end portion of the upper thread U is pulled out from the inside of the intermediate presser 29, and when the next sewing starts. In addition, even if the intermediate presser height control at the start of sewing is executed, the intermediate presser 29 cannot press the sewing start end portion of the upper thread U.
However, when performing thread wiping by the wiper mechanism, if the inner presser 29 is previously retracted by raising and the wiper member is controlled to perform the thread wiping operation below the inner presser 29, the upper thread U Since it is possible to maintain the state in which the sewing start end of the above has passed through the inside of the center presser 29, thread wiping may be performed by the wiper mechanism.

[Intermediate pressing height control during thread trimming]
The CPU 73 of the control device 120 of the sewing machine 100 executes the intermediate presser height control when executing thread trimming, based on the control program 70a in the program memory 70.
In the intermediate presser height control during execution of thread cutting, the CPU 73 causes the intermediate presser 29 to press the sewn material C on the needle plate 110 by the time the moving knife 91 of the thread cutting device 90 executes the cutting. The middle presser motor 42 for controlling the middle presser height is controlled so as to maintain the pressed state by the middle presser 29 at least until the thread trimming device 90 completes the cutting of the sewing thread.

For example, as shown in FIGS. 10(A) and 11(A), the bottom dead center height of the middle presser 29 during sewing is set so that its bottom is higher than the upper surface of the sewing target C. When the sewing needle 108 is raised, a gap S is generated between the lower surface of the sewing target C and the upper surface of the needle plate 110. If thread trimming is performed in this state, the remaining end of the sewing thread is generated in the sewing target C by the length of the gap S.
Therefore, the material to be sewn C is previously pressed against the needle plate 110 by the intermediate presser 29, so that thread cutting is performed in a state where there is no gap S as shown in FIGS. 10(B) and 11(B). Made it possible.
As a result, as shown in FIG. 11B, the length l2 of the remaining end of the sewing thread in the sewing target C for which the intermediate presser height control at the time of thread trimming is executed is changed to the intermediate presser height at the time of executing thread trimming. It is possible to make the gap S shorter than the length l1 of the remaining end of the sewing thread in the sewing target C when the control is not executed.

In the intermediate presser height control at the time of executing the thread trimming, “before the moving knife 91 executes the cutting” means the moment when the moving knife 91 cooperates with the fixed knife 92 to cut the upper thread and the bobbin thread. It means that the intermediate presser 29 starts pressing the sewing object. It goes without saying that the middle presser 29 may start pressing the upper thread U at an earlier stage.
Specifically, before the sewing needle 108 that performs needle drop (needle drop of the last needle) immediately before the moving knife 91 of the thread trimming device 90 starts the cutting operation starts to rise from the bottom dead center, the center presser 29 It is more preferable that the work piece C presses the sewing target C on the needle plate 110.

In the intermediate presser height control at the time of executing the thread trimming, "at least until the thread trimming device 90 completes the cutting of the sewing thread" means that the moving knife 91 cooperates with the fixed knife 92 to obtain the upper thread and the lower thread. It means that the above pressing is continued until the moment when is separated by cutting.

In the intermediate presser control during execution of the thread trimming, the "pressing state by the intermediate presser 29" is the same as the "pressing state by the intermediate presser 29" in the intermediate presser control at the start of sewing described above.

[Overall operation control during sewing]
The CPU 73 of the control device 120 of the sewing machine 100 executes a series of sewing operation control based on the control program 70a in the program memory 70. This series of sewing operation control will be described based on the flowchart of FIG.

First, when the instruction to start sewing is input with the workpiece C set in the holding frame 111, the CPU 73 of the control device 120 reads the needle drop position of the first stitch of the sewing data 71a and sets X. The holding frame 111 is positioned at the needle drop position of the first stitch by driving the shaft motor 76a and the Y-axis motor 77a (step S1). Further, the CPU 73 starts driving the sewing machine motor 2a (step S3).

Then, the CPU 73 executes the intermediate presser height control at the start of sewing, drives the intermediate presser motor 42, and lowers the intermediate presser 29 to the pressing position of the workpiece (step S5).
Then, the sewing needle 108 projects into the needle hole 112 through the material to be sewn, passes through the bottom dead center, and catches the upper thread U by the shuttle, forming a knot with the lower thread.
Then, in the process of raising the sewing needle 108, the CPU 73 monitors from the output of the encoder 2b whether the main shaft angle is the shaft angle for releasing the pressing of the center presser 29 (step S7).
When the axial angle for releasing the pressing of the intermediate presser 29 is detected, the CPU 73 drives the intermediate presser motor 42 so that the intermediate presser height during sewing set in the sewing data 71a is reached (step S9). ).

After that, the CPU 73 reads the needle drop positions of the second and subsequent stitches from the sewing data 71a, and determines whether or not the spindle has reached a prescribed axial angle for moving the workpiece by the moving mechanism (step S11). .. If it has not arrived, the arrival is monitored as it is, and if it has arrived, the holding frame 111 is positioned at the needle drop position of the second stitch by driving the X-axis motor 76a and the Y-axis motor 77a (step S13). ..
Then, it is determined whether or not the next operation defined in the sewing data 71a is thread trimming (step S15). If it is not thread trimming, the process is returned to step S11 to sew the material to the next needle drop position. The move operation of is executed.

On the other hand, if it is determined in step S15 that the next operation is thread trimming, the CPU 73 executes middle presser height control during thread trimming, and the sewing needle 108 is the axis of the main shaft at the bottom dead center. The intermediate presser motor 42 is driven at an angle to lower the intermediate presser 29 to the pressing position of the workpiece (step S17).
Then, the CPU 73 drives the thread trimming motor 96 at the prescribed spindle angle for thread trimming, and reciprocally rotates the moving knife 91 to cut the sewing thread (step S19).
Following this, the CPU 73 drives the intermediate presser motor 42 in the direction in which the intermediate presser 29 rises, continues driving until the intermediate presser retracting mechanism M3 operates, and pulls up the intermediate presser 29 to the retracted position (step). S21).

Then, the CPU 73 stops the sewing machine motor 2a and ends the series of sewing operation control.
In this sewing operation control, since the intermediate presser height control at the start of sewing is executed, the thread wiping operation by the wiper mechanism is not executed. However, the thread wiping operation by the wiper mechanism may be executed as long as the intermediate presser 29 is pulled up above the height at which the wiper passes.

[Effect of Embodiment]
As described above, in the sewing machine 100, since the CPU 73 of the control device 120 executes the intermediate presser height control at the start of sewing, the sewing start end portion of the upper thread U is held by the intermediate presser 29, and the sewing target C It is possible to prevent the first needle from falling out of the needle drop position.
Further, since the intermediate presser device 1 holds the sewing start end portion of the upper thread U, the thread gripping mechanism conventionally mounted on the sewing machine can be dispensed with, which simplifies the apparatus configuration and the control system. It is possible to realize simplification of. In addition, along with this, it is possible to reduce the number of parts of the sewing machine, reduce the manufacturing cost accordingly, and downsize the device.

Further, in the intermediate presser height control at the start of sewing, the CPU 73 of the control device 120 maintains the pressing state by the intermediate press until the sewing needle 108 after the first needle drop reaches the top dead center. When controlling the intermediate presser motor, there are the following effects.
That is, when the sewing needle 108 of the first stitch returns to the top dead center, the raising operation of the sewing needle 108 that applies the tension that causes the needle thread U to fall off at the sewing start end, and the loop of the needle thread by the hook. Since the influences of formation, pulling up by the balance, etc. are almost finished, it is possible to more effectively prevent the work C from falling out from the needle drop position of the first stitch.

When the CPU 73 of the control device 120 controls the intermediate presser motor 42 to release the pressing state by the intermediate presser 29 before the movement of the holding frame 111 to the needle drop position of the second stitch starts, It is possible to avoid that the holding operation of the sewing object and the sewing start end portion of the upper thread U by the presser 29 interferes with the moving operation of the holding frame 111 by the moving mechanism, and each operation can be performed smoothly and satisfactorily. It will be possible.

Further, in the sewing machine 100, the CPU 73 of the control device 120 executes the intermediate presser height control at the time of thread cutting, so that a gap may occur between the sewing target C and the needle plate 110 during thread cutting. Is suppressed, and the remaining end of the sewing thread after thread cutting can be shortened.
Further, since the center presser device 1 shortens the remaining end of the sewing thread, the remaining end processing mechanism conventionally mounted on the sewing machine can be eliminated, the device configuration can be simplified, and the control system can be simplified. Can be realized. In addition, along with this, it is possible to reduce the number of parts of the sewing machine, reduce the manufacturing cost accordingly, and downsize the device.

Further, the CPU 73 of the control device 120 performs the needle drop (needle drop of the last needle) immediately before the moving knife 91 of the thread trimming device 90 starts the cutting operation, before the sewing needle 108 starts to rise from the bottom dead center. When controlling the intermediate presser motor 42 so that the intermediate presser 29 descends to the height at which the sewing target C is pressed on the needle plate 110, the following effects are obtained.
That is, before the sewing needle 108 starts to move upward, the sewing target C can be pressed from above by the intermediate presser 29, and the sewing target C on the needle plate 110 is pulled by the sewing needle 108 to move upward and temporarily. It is possible to suppress the formation of a gap even in the. That is, when the intermediate presser 29 descends after a gap is temporarily created in the material to be sewn, the sewing thread may be caught between the needle plate and the material to be sewn C, but this can be suppressed, It is possible to effectively shorten the remaining end of the sewing thread after thread cutting.

[Other]
The specific description has been given above based on the embodiment according to the present invention. However, the detailed configuration of each mechanism and the detailed operation of each mechanism constituting the sewing machine may be appropriately changed without departing from the gist of the present invention. It is possible.
For example, in the above embodiment, the case where the intermediate presser height control at the start of sewing and the intermediate presser height control at the time of executing thread trimming are applied to a so-called electronic cycle sewing machine is illustrated. These controls can be applied to other sewing machines that are equipped with a.
In addition, the intermediate presser can be separated from the sewing machine motor and have a separate drive source, and the thread presser and the cloth presser can be divided and performed.

1 Middle presser device 2a Sewing machine motor 70a Control program 71 Data memory 71a Sewing data 73 CPU
90 thread trimming device 91 moving knife 92 fixed knife 96 thread trimming motor 100 sewing machine 108 sewing needle 110 needle plate 111 holding frame 112 needle hole 120 control device C sewing target M1 middle press up/down moving mechanism M4 middle press height adjusting mechanism S gap U needle thread (sewing thread)

Claims (5)

A needle up-and-down mechanism that moves the sewing needle up and down,
An intermediate press up/down moving mechanism that moves the intermediate press up and down,
In a sewing machine including an intermediate presser height adjusting mechanism for adjusting the height of the entire vertical movement range of the intermediate presser,
Before the sewing needle starts to plunge into the needle hole of the needle plate at the needle drop of the first stitch at the start of sewing, the intermediate presser descends to a height for pressing the workpiece on the needle plate, and at least the needle A sewing machine comprising a control device that controls the intermediate presser height adjusting mechanism so as to maintain the pressing state by the intermediate presser until the sewing needle comes out from the hole. The control device controls the middle presser height adjusting mechanism so as to maintain the pressing state by the middle presser until the sewing needle after the needle drop of the first stitch reaches the top dead center thereof. The sewing machine according to claim 1, wherein Equipped with a moving mechanism that moves the workpiece by holding it with a holding frame.
The control device controls the middle presser height adjusting mechanism so as to release the pressing state by the middle presser before the movement of the holding frame to the needle drop position of the second stitch starts. The sewing machine according to Item 1. A needle up-and-down mechanism that moves the sewing needle up and down,
An intermediate press up/down moving mechanism that moves the intermediate press up and down,
An intermediate presser height adjusting mechanism for adjusting the height of the entire vertical movement range of the intermediate presser,
In a sewing machine including a thread cutting device for cutting a sewing thread,
By the time the moving knife of the thread trimming device executes cutting, the inner presser is lowered to a height at which the sewing target is pressed onto the needle plate, and at least until the thread trimming device completes cutting of the sewing thread. A sewing machine comprising a control device that controls the intermediate presser height adjusting mechanism so as to maintain a pressed state by the intermediate presser. The control device is
The intermediate presser descends to a height at which the sewing workpiece is pressed onto the needle plate before the sewing needle that starts moving immediately before the cutting operation of the thread cutting device starts cutting operation and the sewing needle starts to rise from the bottom dead center. The sewing machine according to claim 4, wherein the middle presser height adjusting mechanism is controlled as described above.

Images