JP6918530B2 - Flat stitch sewing machine - Google Patents

Description

The present invention relates to a flat stitch sewing machine.

In a conventional flat sewing machine, a feed dog that appears and disappears from the lower side of the needle plate on the needle plate and a cloth presser that presses the sewn object on the needle plate from above are used to feed the sewing machine while holding the fabric up and down. I was sewing.
However, since the upper cloth on which the sewn objects are stacked is pressed by the cloth retainer and the lower cloth is fed directly in contact with the feed dog, there is a difference in the feed amount between the upper and lower cloths. There is a risk that the sewn material may become loose and the sewing quality may deteriorate.

In order to solve the above problems, it is being studied to divert the feed mechanism of the vertical feed sewing machine to a flat stitch sewing machine.
In the vertical feed sewing machine, on the upper side of the needle plate, the feed foot that swings back and forth along the feed direction and the presser foot that does not swing alternately move up and down, and feed at the timing when the feed foot is descending. The feed foot swings toward the downstream side in the direction, and the feed foot swings toward the upstream side in the feed direction at the timing when the holding foot descends and the feed foot rises (see, for example, Patent Document 1).
Then, since the feed dog and the feed foot feed the sewn object in synchronization with each other, it is possible to reduce the difference in the feed amount generated between the upper cloth and the lower cloth of the sewn product.

Japanese Unexamined Patent Publication No. 2010-057906

However, the vertical feed mechanism using the feed foot of Patent Document 1 has a structure in which the sewn object is sandwiched between the feed dog and the feed foot from above and below and fed, so that the sewn object is thick or has a step. In that case, the holding pressure becomes high and there is a risk of damaging the sewn object.

An object of the present invention is to provide a flat stitch sewing machine that provides good feed.

The invention according to claim 1 is a flat sewing machine.
In a flat sewing machine that forms a plurality of stitches along the feed direction of an object to be sewn by a plurality of sewing needles and performs flat stitching by sewing a decorative thread that crosses between the plurality of stitches.
It is provided with an upper belt mechanism equipped with a plurality of feed belts that are in contact with the sewn object on the needle plate from above and feed the sewn object in the feed direction and a feed motor that is a drive source for the feed operation.
A plurality of feed belts of the upper belt mechanism, possess a central belt in contact with the workpiece in the feed direction downstream relative to the needle drop position, and a lateral belt in contact with the workpiece next to the central belt ,
The bottom portion of the central belt is arranged at a position lower than the bottom portion of the side belt .

The invention according to claim 2 is the flat sewing machine according to claim 1.
The central belt is arranged so that the position in contact with the sewn object and the needle drop position are aligned along the feed direction, and is in contact with the sewn object on the downstream side in the feed direction with respect to the needle drop position. The feature is that they are arranged in such a manner.

The invention according to claim 3 is the flat sewing machine according to claim 1 or 2.
The two side belts are arranged on both sides of the central belt.

The invention according to claim 4 is the flat stitch sewing machine according to any one of claims 1 to 3.
A control device for controlling the feed rate by the feed motor is provided.
The control device is characterized by including an adjustment dial for setting and inputting the feed speed of the feed motor by a rotation operation.

The invention according to claim 5 is the flat stitch sewing machine according to any one of claims 1 to 4.
The upper belt mechanism includes two feed motors.
One of the plurality of feed belts, the side belt, and the remaining other feed belts are individually driven by the two feed motors.

The invention according to claim 6 is the flat stitch sewing machine according to any one of claims 1 to 5.
The plurality of feed belts are supported so as to be transportable by a pressing plate that presses the object to be sewn from above.
The holding plate is supported so that the upstream end in the feed direction can be raised and lowered with the downstream end in the feed direction as a fulcrum, and the upstream end in the feed direction is elastically supported in the downward direction by an elastic member. It is characterized by being granted.

The invention according to claim 7 is the flat stitch sewing machine according to any one of claims 1 to 6.
The plurality of feed belts are supported so as to be transportable by a pressing plate that presses the object to be sewn from above, and are arranged so as to be inclined upward on the downstream side of the pressing plate in the feed direction.
A convex member is provided on the downstream side in the feed direction from the holding plate so as to be convex on the downstream side in the feed direction with respect to the plurality of feed belts.

The invention according to claim 8 is the flat sewing machine according to claim 7.
The lower end of the convex member is characterized in that the downstream side in the feed direction is inclined upward.

The invention according to claim 9 is the flat stitch sewing machine according to any one of claims 1 to 8.
It is provided with a lower belt mechanism equipped with a plurality of feed belts that are in contact with the sewn object on the needle plate from below and feed the sewn object in the feed direction and a feed motor that is a drive source for the feed operation.
The plurality of feed belts of the lower belt mechanism have a central belt that contacts the sewn object on the downstream side in the feed direction with respect to the needle drop position, and a side belt that contacts the sewn object next to the central belt. It is characterized by.

According to the above configuration, since the feed motor is provided in the present invention, the feed amount can be adjusted individually for the upper portion and the lower portion of the sewn object, and since the feed belt is in contact with the sewn object, the sewn object has a step. It is possible to reduce the occurrence of scratches even on sewn objects and thick sewn objects.

It is a perspective view of the flat stitch sewing machine which is 1st Embodiment. It is a perspective view around the needle drop position of a flat stitch sewing machine. It is a side view of the cloth holding mechanism and the upper belt mechanism. It is a perspective view of the lower end part of the cloth holding mechanism and the upper belt mechanism. It is a perspective view of a cloth retainer. It is a front view of the holding plate of the cloth holding. It is an enlarged perspective view of the cloth retainer. It is a side view of the cloth retainer. It is a side view of another example of the upper belt mechanism provided with two feed motors. It is a perspective view around the needle plate of the flat stitch sewing machine which is a 2nd Embodiment. It is a perspective view of the lower belt mechanism mounted on the flat stitch sewing machine. It is a side view of the lower belt mechanism.

[Outlined configuration of the first embodiment]
The flat stitch sewing machine 10 according to the first embodiment will be described with reference to FIGS. 1 to 8.
FIG. 1 is a perspective view of the flat stitch sewing machine 10, and FIG. 2 is a perspective view of the flat stitch sewing machine 10 around the needle drop position.
In the following description, one horizontal direction is defined as the X-axis direction, and the horizontal and orthogonal directions are defined as the Y-axis direction and the vertical Z-axis direction. Further, as shown in FIG. 1, one of the X-axis directions is "front", the other is "rear", one of the Y-axis directions is "left", and the other is "right".

The flat sewing machine 10 includes a sewing machine frame 20, a needle vertical movement mechanism (not shown) that moves two sewing needles 11 up and down using the sewing machine motor as a drive source, and a lower looper that uses the sewing machine motor as a drive source on the lower side of the needle plate 12. A lower looper mechanism (not shown) that reciprocates to insert the lower looper thread into the loop of the upper thread of the two sewing needles, and an upper decorative thread for the two stitches formed by the two sewing needles 11. A spreader mechanism (not shown) that guides the upper decorative thread so that it is sewn in the Y-axis direction, and a feed dog that appears and disappears from the lower side of the needle plate 12 to feed the sewing machine along the X-axis direction on the downstream side in the feed direction. A lower feed mechanism (not shown) that feeds to the sewing machine, a cloth presser mechanism 30 that presses the sewn object from above by the cloth retainer 31, and a feed belt that contacts the sewn object on the needle plate 12 from above and downstream of the feed direction ( The upper belt mechanism 50 to be sent to the front), the cloth cutting mechanism 80 to cut the end of the folded sewing machine, the thread tension mechanism 13, the balance mechanism 14, and the control device 90 to control each of the above configurations. It has.

[Sewing machine frame]
The sewing machine frame 20 includes a sewing machine bed portion 21 extending along the Y-axis direction at the lower part of the flat sewing machine 10, a standing body portion 22 erected from one end of the sewing machine bed portion 21, and a standing body portion 22. It includes a sewing machine arm portion 23 extending in the same direction as the sewing machine bed portion 21 from the upper end portion.
A needle plate 12 is provided on the upper surface of the end portion of the sewing machine bed portion 21 opposite to the standing body portion 22, and the needles are dropped by the two sewing needles 11 into the needle holes formed in the needle plate 12.

[Needle vertical movement mechanism]
The needle vertical movement mechanism consists of a needle rod 15 (see FIG. 3) that is supported so as to be vertically movable along the Z-axis direction at the tip of the sewing machine arm portion 23, and two needle rods that are held at the lower end of the needle rod 15. The sewing needle 11 and a crank mechanism for imparting a vertical movement to the needle rod 15 from the sewing machine motor are provided.
The needle bar 15 holds two sewing needles 11 arranged side by side in the Y-axis direction at the lower end thereof.
In the flat stitch sewing machine 10, the sewn object is conveyed toward the front in the X-axis direction, and two stitches arranged in the Y-axis direction are formed along the X-axis direction by the two sewing needles 11.

[Thread tension mechanism and balance mechanism]
The flat stitch sewing machine 10 sews with two upper threads, a lower looper thread, and an upper decorative thread, and the thread tension mechanism 13 is composed of a plurality of thread tensioners that apply thread tension to each of these threads. ..

The balance mechanism 14 includes a swing-type balance through which two needle threads to which thread tension is applied in the thread tension mechanism 13 are inserted. This balance obtains the power of swinging from the sewing machine motor, and swings in synchronization with the vertical movement of the sewing needle 11 to pull up each needle thread at an appropriate timing.

[Lower looper mechanism]
The lower looper mechanism is arranged inside the sewing machine bed portion 21 and includes a lower looper that performs a reciprocating forward / backward movement along the Y-axis direction and a transmission mechanism that imparts a forward / backward movement from the sewing machine motor to the lower looper.
The lower looper is a sharp member extending toward the left side in the Y-axis direction, and a threading hole through which the lower looper thread is inserted is formed at the tip thereof and is arranged below the needle plate 12. There is. Then, when advancing toward the left, it rushes into the loop of the needle thread passed through the two lowered sewing needles 11, and makes it possible to insert the lower looper thread into the loop of the two needle threads. There is.
Further, the two sewing needles 11 that have descended into the loop of the lower looper thread formed when the lower looper retracts to the right rush into the loop, and the two upper threads are inserted. By repeating these alternately, two seams along the X-axis direction are formed.

[Spreader mechanism]
The spreader mechanism is provided above the needle plate and includes a spreader that guides the upper decorative thread at the tip portion and a rotation mechanism that gives a rotating motion so that the tip portion of the spreader reciprocates along the Y-axis direction. ing.
The rotation mechanism uses the sewing machine motor as a drive source to apply the reciprocating rotation operation of the spreader in synchronization with the vertical movement of the sewing needle 11.
The upper decorative thread guided by the spreader is swung left and right in synchronization with the needle drop of the two sewing needles 11, and can be sewn alternately to the two seams formed in the sewing object. ..

[Downward feed mechanism]
The lower feed mechanism includes a feed dog that allows the tip of the tooth to appear and disappear from the opening of the needle plate 12, and a circumferential mechanism that orbits the feed dog in an oval locus along the X-axis direction.
The orbiting mechanism is provided with a horizontal feed shaft and a vertical feed shaft that rotate reciprocally using a sewing machine motor as a drive source, and feeds the feed table that supports the feed dog by giving a reciprocating motion in the X-axis direction to the feed table that supports the feed dog. The teeth are given an oval orbital motion.
When the feed dog passes through the upper part of the oval locus, the tip of the tooth protrudes upward from the opening of the needle plate, and at that time, the feed dog moves forward. As a result, the tooth tips come into contact with the sewn object on the needle plate from below, and the sewn object can be intermittently fed forward at a constant feed pitch.

[Cloth excision mechanism]
The sewn object C is a fabric whose right edge is folded downward, and the cloth cutting mechanism 80 is the width of the folded portion of the sewn object C in the Y-axis direction on the upstream side in the cloth feeding direction from the needle drop position. The tip of the folded portion is cut off in order to make the folded portion uniform.

As shown in FIG. 2, the cloth cutting mechanism 80 has a positioning ruler 81 to which the right edge portion, which is a crease of the folded portion C1 (see FIG. 5) of the sewn object C during sewing, is abutted, and a bottom of the sewn object C. It is provided with a fixed scalpel 82 and a moving scalpel 83 for cutting off the left edge folded back on the side, and a scalpel vertical movement mechanism for moving the moving scalpel 83 up and down.

The positioning ruler 81 is a flat plate-shaped member along the XZ plane, and a crease portion (right edge portion) of the object to be sewn C is abutted against the left plane thereof. The position of the positioning ruler 81 can be adjusted along the Y-axis direction, whereby the width of the folded portion of the sewn object C in the Y direction can be adjusted.
The fixed scalpel 82 is arranged with the tooth tips facing upward, and the moving scalpel 83 descends toward the tooth tips of the fixed scalpel and passes between the fixed scalpel 82 and the moving scalpel 83. The folded left edge can be excised.
The female vertical movement mechanism includes a drive shaft that reciprocates with the sewing machine motor as a drive source, and supports the moving female 83 at the tip of the drive shaft. Then, the moving scalpel 83 is given a reciprocating rotation motion, so that the tip portion thereof can be moved up and down to cut the sewn object C.

[Cloth holding mechanism]
FIG. 3 is a side view of the cloth holding mechanism 30 and the upper belt mechanism 50, FIG. 4 is a perspective view of the lower end portion of the cloth holding mechanism 30 and the upper belt mechanism 50, and FIG. 5 is a perspective view of the cloth holding mechanism 31.
As shown in FIGS. 2 to 5, the cloth pressing mechanism 30 manually includes a cloth pressing 31, a pressing rod 32 that supports the cloth pressing 31 at the lower end portion, an air cylinder 33 that applies pressing pressure to the cloth pressing 31, and a manual operation. It is provided with a pressing pressure releasing mechanism 34.

The pressing rod 32 is supported so as to be vertically movable at the tip end portion of the sewing machine arm portion 23, and the upper end portion thereof is connected to the plunger of the air cylinder 33. Then, by operating the air cylinder 33, it is possible to switch between applying the pressing pressure to the sewn object C by the cloth pressing 31 and releasing the pressing pressure by raising the cloth pressing 31.

Further, the air cylinder 33 is provided with two valves 331 and 332 to which air pressure air is supplied from an external air pressure source, and one valve 331 is provided with a pressure reducing valve (not shown) from an external air pressure source. low pressure through (e.g., 2 kgf / cm ²⁾ air is supplied, air is supplied in a high pressure (e.g., 4 kgf / cm ²⁾ without passing through the pressure reducing valve from the outside of the air pressure source to the other of the valve 332 ..
Each of the valves 331 and 332 has manual push buttons 333 and 334 for switching between supply and stop of air, and by switching the push buttons 333 and 334, the pressing pressure of the cloth retainer 31 is increased. The strength can be switched.

As shown in FIG. 3, the pressing pressure releasing mechanism 34 is fixedly equipped on a rod holding 341 fixedly equipped on the pressing rod 32, an input shaft 342 connected to a manual pressing lever (not shown), and an input shaft 342. It includes a rotating arm 343 and a link member 344 that connects the rotating end of the rotating arm 343 and the rod holding 341.
With this configuration, when the pressing lever is manually rotated counterclockwise, the rotating end of the rotating arm 343 rotates upward via the input shaft 342, and the pressing rod 32 via the link member 344. And the cloth retainer 31 can be pulled up.

As shown in FIGS. 3 to 8, the cloth retainer 31 includes a retainer plate 311 and an upright portion 312 provided in the center of the front side of the retainer plate 311. In FIG. 5, the vertical portion 312 is not shown.
The upper end of the upright portion 312 is provided with a connecting hole into which the lower end of the pressing rod 32 can be inserted, and the pressing rod 32 can be held by a headless screw.

The pressing plate 311 has a function of applying the pressing pressure from the air cylinder 33 described above to the object to be sewn C, and in the central portion of the pressing plate 311, two needle insertion portions 313, which penetrate vertically, are formed. 314 is formed. Through the needle insertion portions 313 and 314, the needles are dropped by the two sewing needles 11 and 11 with respect to the sewing object C on the lower side of the pressing plate 311.

Further, the holding plate 311 is a central belt 511 which is three feed belts of the upper belt mechanism 50, which will be described later, so as to pass through the bottom surface from the upper surface of the pressing plate 311 via a position slightly forward of the rear end portion or the rear end portion. It also has a function of guiding the left belt 512 and the right belt 513 so that they can be conveyed in the feed direction.
Therefore, a first left roller 351 and a second left roller 352 for conveying the left belt 512 are rotatably arranged at the left rear end portion and the left front end upper portion of the holding plate 311.
Further, a first right roller 353 and a second right roller 354 for conveying the right belt 513 are rotatably arranged at the right rear end portion and the upper right front end portion of the pressing plate 311.

Further, a wide notch is formed from the front end portion to the central portion of the holding plate 311, and the first central roller 355 and the second central roller 356 for transporting the central belt 511 rotate in front of and behind the inside thereof. Arranged as possible. A third central roller 357 is rotatably arranged above the central front end of the holding plate 311.
The second left roller 352, the second right roller 354, and the third center roller 357 are supported not by the holding plate 311 but by the standing portion 312.

With these rollers 351 to 357, the center belt 511, the left belt 521, and the right belt 513 can be smoothly conveyed forward while being aligned in the Y-axis direction and the bottom surface of the holding plate 311. The upper surface of the sewn object C can be fed forward while being in contact with the upper surface of the sewn object C by the pressing pressure of the pressing plate 311.

Further, the first central roller 355 is arranged side by side with the needle insertion portions 313 and 314 which are the needle drop positions along the X-axis direction (feed direction), and is in front of the needle insertion portions 313 and 314 (). It is located on the downstream side in the feed direction).
On the other hand, the first left roller 351 and the first right roller 353 are located on the left and right sides of the needle insertion portions 313 and 314, and are rearward (upstream side in the feed direction) of the needle insertion portions 313 and 314. Is located in.
As a result, the central belt 511 is in contact with the sewn object on the downstream side in the feed direction from the needle drop position and feeds, and the left belt 512 and the right belt 513 are sewn on the upstream side in the feed direction from the needle drop position. Send in contact with.

Further, as shown in FIG. 6, the central belt 511, the left belt 512, and the right belt 513 are supported at different heights at their bottoms in contact with the sewn object C. That is, the central belt 511 is supported so that its bottom is at the lowest position, the bottom of the left belt 512 is at the next lowest position, and the bottom of the right belt 513 is at the highest position.
The height of the bottom of the central belt 511 is adjusted by the installation height of the first central roller 355 and the second central roller 356, and the height of the bottom of the left belt 512 and the right belt 513 is the holding plate 311. It is adjusted by the depth of the grooves 311a and 311b that guide the respective belts formed on the bottom surface side of the.

For this reason, the central belt 511 is in a state of being most pressed against the sewn object C with respect to the central portion where resistance to the feed is likely to occur due to the needle dropping, so that the delay to the left and right is suppressed. Therefore, it becomes possible to stably feed the sewn product.
Further, when the right edge of the sewn object C is folded back and sewn, the folded-back portion C1 does not exist on the left side of the needle drop position, and the sewn object is substantially thinner on the left side than the right side of the needle drop position. Therefore, by arranging the bottom of the left belt 512 at a position lower than the bottom of the right belt 513, the left belt 512 and the right belt 513 can be pressed against the sewn material in a well-balanced manner on the left and right, and left and right. It is possible to stably feed the sewn object C without bias.

Further, as shown in FIG. 7, the front end portion (downstream end portion in the feed direction) of the holding plate 311 is pivotally supported around the Y-axis with respect to the erection portion 312 by a fulcrum shaft (not shown). .. As a result, the rear end portion (upstream end portion in the feed direction) of the holding plate 311 swings with a fulcrum shaft (not shown) provided at the downstream end portion in the feed direction of the holding plate 311 as a fulcrum, and can be moved up and down. It has become.
Further, the left side surface of the holding plate 311 is equipped with a torsion coil spring 316 as an elastic member by a step screw 315, one end of the torsion coil spring 316 is locked to the standing portion 312 side, and the other end is. It is in pressure contact with the upper surface of the rear end portion of the pressing plate 311. As a result, the holding plate 311 is in a state in which an elastic force downward is applied to the rear end portion thereof.
In FIG. 7, the belts 511 to 513 and the rollers 351 to 357 are not shown.

Since the pressing plate 311 is pressed downward by the air cylinder 33 via the pressing rod 32, the bottom surface of the pressing plate 311 is maintained in a horizontal state to press the sewn object C during normal sewing. ..
However, since the holding plate 311 can swing with respect to the upright portion 312 as described above, the sewn object C has a step portion, and the step portion is fed from the rear to the front. Then, the rear end portion of the holding plate 311 swings upward against the torsion coil spring 316 to easily get over the stepped portion, and smoothly and satisfactorily feeds the sewn object C having the stepped portion. Can be done.

Further, as shown in FIG. 8, the central belt 511 and the left belt 512 and the right belt 513 are all located diagonally upward from the front end portion (downstream side end portion in the feed direction) of the presser plate 311 of the cloth retainer 31. It extends toward the same inclination angle.
A convex member 317 is formed at a position of the front end portion (downstream side end portion in the feed direction) of the upright portion 312 of the cloth retainer 31 and in front of the front end portion of the pressing plate 311. The convex member 317 extends diagonally upward when viewed from the side, and is convex toward the front of the central belt 511 and the left belt 512 and the right belt 513.
The convex member 317 has a downwardly inclined surface 317a that extends diagonally upward from a position substantially the same as the front end of the bottom surface of the holding plate 311 when viewed from the side. Further, the convex member 317 is arranged so as not to overlap each of the belts 511 to 513 when viewed from the X-axis direction.
The inclined surface 317a is inclined upward at a gentler angle than each belt 511,512,513. Therefore, the convex member 317 is in a state of protruding forward and downward from each of the belts 511 and 512, 513 when viewed from the side.

Assuming that the convex member 317 does not exist, the sewn object C sent forward by each belt 511, 512, 513 is made to be convex upward in front of the front end portion of the bottom surface of the holding plate 311. Looseness is likely to occur. When such slack occurs, the good feeding operation of the sewn object C is hindered, so that the sewing machine operator needs to sew while pulling the sewn object C forward so as not to cause the slack. ..
However, by providing the convex member 317 at the front end portion of the cloth retainer 31, there is no space for the sewn object C to slacken in front of the front end portion of the bottom surface of the presser plate 311, and the occurrence of slack can be suppressed. It becomes.
Further, since the lower portion of the convex member 317 has a shape having an inclined surface 317a, the sewn object C can be satisfactorily sent forward while eliminating the slack. As a result, it is not necessary for the sewing machine operator to pull the sewing machine C forward, and the workability at the time of sewing can be improved.

The lower portion of the convex member 317 exemplifies an inclined surface 317a that goes straight upward diagonally forward, but the shape is not limited to this. For example, the lower portion of the convex member 317 may have a curved surface that gradually rises while being curved from the same horizontal state as the bottom surface of the pressing plate 311.
Further, the convex member 317 may be integrally formed with the upright portion 312 of the cloth retainer 31, but may be formed by another member.

[Upper belt mechanism]
The upper belt mechanism 50 includes an endless annular center belt 511, a left belt 512, a right belt 513 as a plurality of feed belts, a feed motor 52 as a drive source for belt feed, and each belt from the feed motor 52 to the cloth retainer 31. It is provided with a guide mechanism 53 that guides 511 to 513.

As the feed motor 52, a motor whose rotation speed can be controlled, for example, a DC motor, an AC motor, a stepping motor, or the like is used.
The feed motor 52 is fixedly mounted on the front surface side of the tip end portion of the sewing machine arm portion 23 via the motor bracket 521 in a state where the output shaft is directed to the left.
Further, the output shaft of the feed motor 52 is equipped with a motor pulley 522 around which one end of each belt 511 to 513 is wound.

The guide mechanism 53 mainly includes a guide arm 533 composed of first and second link members 531, 532, and a plurality of rotatably provided guides in each part of the belt path from the motor pulley 522 to the cloth retainer 31. It is composed of a roller 534.

One end of the first link member 531 of the guide arm 533 is rotatably connected to the lower part of the motor bracket 521 around the Y axis, and the other end is rotatably connected to one end of the second link member 532 around the Y axis. It is rotatably connected to.
The other end of the second link member 532 is rotatably connected to the fastening member 535, which is hugged to the lower end of the pressing rod 32 just above the cloth retainer 31, around the Y axis.

Both the first link member 531 and the second link member 532 are paired on the left and right and have flat side wall portions along the XZ plane, and the side wall portions face each other. The guide rollers 534 are arranged at each position on the facing surfaces of the side wall portions of the link members 531, 532 facing each other, whereby the belt paths of the belts 511 to 513 are connected to the link members of the guide arm 533. It is formed along 531,532.

The guide roller 534 is arranged at each position of the motor bracket 521 in addition to the link members 531, 532.
Each guide roller 534 is a tension roller arranged in a pressure contact state so that the belts 511 to 513 do not loosen, in addition to those arranged at the corners of the path to form a predetermined belt path. Some of them function as.

One end of each belt 511 to 513 is wound around the motor pulley 522, and the other end is wound around each roller 351 to 357 provided on the cloth retainer 31 via each guide roller 534.
As a result, when the feed motor 52 is driven, the belts 511 to 513 are conveyed forward on the bottom surface side of the cloth retainer 31 by the torque thereof.

In principle, the rotation speed of the feed motor 52 is such that the transport speed of each belt 511 to 513 on the bottom surface of the cloth retainer 31 is a continuous feed speed by averaging the intermittent feed speed by the lower feed mechanism. It is controlled to match the converted virtual feed rate.
However, if there is a difference in feed rate between the upper portion and the lower portion of the sewn object C, adjustment control is performed to increase or decrease the rotation speed of the feed motor 52.

Further, when the pressing pressure is released, the cloth pressing 31 moves up to the upper retracted position via the pressing rod 32, so that the other end of the second link member 532 of the guide arm 533 is pressed. Although it moves upward together with the rod 32, both ends of the guide arm 533 are rotatably connected around the Y axis, and the first link member 531 and the second link member 532 can also rotate around the Y axis. Since they are connected, it is possible to cope with the rise of the cloth retainer 31 by changing the bending angle between the first link member 531 and the second link member 532.

[Control device]
The control device 90 is a control circuit including a CPU, RAM, data memory, etc., and is connected to a sewing machine motor, a feed motor 52, etc. via a driver circuit to control the start / stop, drive speed, etc. of these drives. be able to.
Further, the operation panel 91 and the adjustment dial 92 shown in FIG. 1 are connected to the control device 90 via an interface (not shown).

The operation panel 91 includes input units such as buttons and keys for inputting various settings related to sewing, and a display unit for displaying to assist the setting work.
From the operation panel 91, for example, the rotation speed of the sewing machine motor, the feed rate of the object to be sewn by the upper belt mechanism 50, the start of sewing, and the like are input.
The feed rate of the sewn object by the upper belt mechanism 50 is not limited to the direct speed, and may be, for example, input of a speed difference or a speed ratio with respect to the feed speed of the lower feed mechanism.
At the time of setting various numerical values, for example, the increase / decrease key is used to input the increase / decrease of the set value displayed on the display unit, and the enter key is used to determine the set value.

The adjustment dial 92 can be rotated and input, and the input amount is detected by a rotation amount detection sensor such as a built-in encoder and input to the control device 90.
The adjustment dial 92 is an input means for exclusively inputting the adjustment of the feed rate of the upper belt mechanism 50, and inputs an increase in the set value of the feed rate of the upper belt mechanism 50 in the forward rotation, and inputs the increase in the feed rate of the upper belt mechanism 50 in the reverse rotation. Enter the reduction of the set value.
Further, the increase or decrease of the feed speed set value input from the adjustment dial 92 may be reflected in the speed control of the feed motor 52 in real time at the time of rotation operation, or may be set by rotation operation with the adjustment dial 92. After inputting the value, the input operation of determination may be performed by the determination key or the like, and then the value may be reflected in the speed control of the feed motor 52. Further, when performing a decision input operation with the decision key or the like, the decision key on the operation panel 91 may be used, or the dial of the adjustment dial 92 can be pushed and clicked, and these push or click operations can be performed. It may be decidable.

[Technical effect of the first embodiment]
The flat sewing machine 10 includes a feed motor 52 that drives the feed operation of the sewing machine C, a central belt 511 that contacts the sewing machine C on the downstream side in the feed direction with respect to the needle drop position, and a central belt 511. Since the upper belt mechanism 50 is provided with the left belt 512 which is in contact with the sewing machine C on the left side and the right belt 513 which is in contact with the sewing machine C on the right side of the center belt 511, the speed of the feed motor 52 can be increased. By controlling the sewing machine separately from the sewing machine motor, it is possible to reduce the difference in the feed amount between the upper portion and the lower portion of the sewn object C.
Further, since each belt 511, 512, 513 is in contact with the upper side of the sewn object C to feed the sewn object C, the sewn object C having a step or thickness is different from the case where the sewn object C is sandwiched by the feed dogs from above and below and sent out. It is possible to reduce the occurrence of scratches and indentations caused by the pinching pressure.

Further, the central belt 511 is arranged so that the position in contact with the object to be sewn C and the needle drop position are aligned along the X-axis direction, and is sewn on the downstream side (front side) in the feed direction with respect to the needle drop position. It is arranged so as to be in contact with the object C.
Therefore, when the sewing needle 11 is stuck in the sewing object, resistance is generated and the feeding of the sewing object C is more likely to be delayed than on the left and right, but the central belt 511 is on the downstream side in the feeding direction of the needle drop position. By arranging them so as to be in contact with each other, the sewn object C can be fed by pulling, so that the delay in the central portion can be reduced and the sewn object C can be fed satisfactorily as a whole.

Further, since the bottom of the central belt 511 is arranged at a position lower than the bottom of the left belt 512 and the right belt 513, the central belt 511 is the most suitable for the central portion where resistance to feed is likely to occur due to needle dropping. Since it is in a state of being pressed against the sewn object C, it is possible to suppress the delay to the left and right and stably feed the sewn object.
Further, since the left belt 512 and the right belt 513 are arranged on both sides of the central belt 511 in the Y-axis direction, the three belts 511 to 513 make it possible to perform feed with excellent straightness.

Further, since the flat sewing machine 10 includes a control device 90 for controlling the feed rate by the feed motor 52, the ratio of the feed amount by the upper belt mechanism 50 to the lower feed mechanism can be arbitrarily adjusted. The upper portion and the lower portion of the sewn product C can be fed properly in a well-balanced manner, and the sewing quality can be improved.
Further, since the control device 90 is provided with the adjustment dial 92, the feed amount of the lower feed mechanism can be adjusted with high operability, and the adjustment work can be performed intuitively, so that even during sewing or the like. It can be adjusted freely.

Further, the holding plate 311 of the cloth holding 31 of the cloth holding mechanism 30 is supported so that the upstream end in the feeding direction can be raised and lowered with the downstream end in the feeding direction as a fulcrum, and the upstream end in the feeding direction is supported. Elastic force is applied in the downward direction by the torsion coil spring 316.
Therefore, even if the sewn object C has a stepped portion or a portion whose thickness changes, the upstream end portion of the pressing plate 311 in the feed direction moves up and down to maintain a state of being in close contact with the sewn object C. It is possible to suppress fluctuations in the feed amount and perform a stable feed operation.

Further, the cloth presser 31 of the cloth presser mechanism 30 is provided with a convex member 317 that is convex on the downstream side in the feed direction with respect to the plurality of belts 511 to 513 on the downstream side in the feed direction from the presser plate 311. ..
As a result, there is no space for the sewn object C to slacken in front of the front end of the bottom surface of the pressing plate 311, and it is possible to suppress the occurrence of slack.
Further, since the lower portion of the convex member 317 has an inclined surface 317a, the sewn object C can be satisfactorily sent forward while eliminating the slack, and the sewing machine operator pulls the sewn object C forward. Work is not required, and workability at the time of sewing can be improved.

[Other examples of upper belt mechanism]
FIG. 9 shows another example of the upper belt mechanism. The upper belt mechanism 50A is different from the above-mentioned upper belt mechanism 50 in that it includes two feed motors 52, and is substantially the same in other points. Therefore, with respect to the upper belt mechanism 50A, the same components as those of the upper belt mechanism 50 are designated by the same reference numerals, and redundant description will be omitted.

The upper belt mechanism 50A includes a motor bracket 521A that supports two feed motors 52, 52 side by side, and the motor bracket 521A is attached to the sewing machine arm portion 23 at the same position as the motor bracket 521 described above. There is.
The output shaft of each feed motor 52 is equipped with a motor pulley 522, only the left belt 512 is wound around the motor pulley 522 of the upper feed motor 52, and the motor pulley of the lower feed motor 52 is wound. A central belt 511 and a right belt 513 are wound around the 522.
Alternatively, even if the left belt 512 and the center belt 511 are wound around the motor pulley 522 of the upper feed motor 52 and only the right belt 513 is wound around the motor pulley 522 of the lower feed motor 52. good.

In this way, by configuring the left belt 512 and the right belt 513 to be conveyed by separate feed motors 52, the feed speeds of the two feed motors 52 and 52 are controlled to be different, so that the sewing is sewn. It is possible to control the feed direction of the object C to be right-turned or left-turned, and it is possible to easily and satisfactorily cope with sewing of a right-handed or left-turned object. Further, by arbitrarily setting the feed rate difference between the two feed motors 52 and 52, it is possible to control the curvature of right-turning or left-turning.

It is desirable that the feed speed difference between the two feed motors 52 and 52 is set by the input operation of the operation panel 91 described above.
Further, another adjustment dial which is the same as the adjustment dial 92 described above may be provided, and the feed speed difference between the two feed motors 52 and 52 may be set and input by the forward rotation or the reverse rotation of the new adjustment dial.
Further, three feed motors may be provided, and the belt feed speed may be individually controlled by the central belt 511, the left belt 512, and the right belt 513.

[Second Embodiment]
The flat stitch sewing machine 10B, which is the second embodiment, will be described with reference to FIGS. 10 to 12.
10 is a perspective view of the needle plate of the flat stitch sewing machine 10B, FIG. 11 is a perspective view of the lower belt mechanism 70B mounted on the flat stitch sewing machine 10B, and FIG. 12 is a side view of the lower belt mechanism 70B.
Regarding the flat stitch sewing machine 10B, one horizontal direction is defined as the X-axis direction, and the horizontal and orthogonal directions are defined as the Y-axis direction and the vertical Z-axis direction. Further, as shown in FIG. 1, one of the X-axis directions is "front", the other is "rear", one of the Y-axis directions is "left", and the other is "right".

The flat sewing machine 10B is different from the flat sewing machine 10 in that it is provided with a lower belt mechanism 70B that feeds from below to the object to be sewn C on the needle plate 12B instead of the above-mentioned lower feed mechanism.
Therefore, in the following description, the same configuration as that of the flat stitch sewing machine 10 will be designated by the same reference numerals and description thereof will be omitted, and the lower belt mechanism 70B will be mainly described.

[Lower belt mechanism]
The lower belt mechanism 70B is composed of an endless annular center belt 711B as a plurality of feed belts, a left belt 712B, a right belt 713B, a lower feed motor 72B as a feed motor as a drive source for belt feed, and a lower feed motor 72B. It is provided with a guide mechanism 73B that guides each belt 711B to 713B along a path passing through the needle plate 12B.

As the lower feed motor 72B, a motor whose rotation speed can be controlled, for example, a DC motor, an AC motor, a stepping motor, or the like is used.
The lower feed motor 72B is fixedly mounted on the front side of the tip end portion of the sewing machine bed portion 21 via the motor bracket 721B in a state where the output shaft is directed to the right.
Further, the output shaft of the lower feed motor 72B is equipped with a motor pulley 722B around which a part of each belt 711B to 713B is wound.

The guide mechanism 73B is provided on the guide frame 731B for guiding each belt 711B to 713B, a plurality of guide rollers 732B forming a belt path of the central belt 711B extending from the motor pulley 722B to the needle plate 12B, and the guide frame 731B. , A guide roller 733B for transportably supporting the left belt 712B and the right belt 713B is provided so as to go around the outer circumference of the sewing machine bed portion 21.

The guide frame 731B is a frame body substantially rectangular when viewed from the Y-axis direction, and is mounted on the sewing machine bed portion 21 so as to surround the tip portion of the sewing machine bed portion 21.
Further, the upper portion of the guide frame 731B is connected to the needle plate 12, and the belts 711B to 713B supported by the guide frame 731B can be guided to the upper surface of the needle plate 12B.

The guide roller 732B of the central belt 711B is provided at a position between the motor pulley 722B and the needle plate 12B and a position near the needle hole 121B of the needle plate 12B and on the downstream side in the feed direction of the needle hole 121B. ing.
The needle plate 12B is notched from the center of the front end portion to the front of the needle hole 121B, and one of the guide rollers 732B is arranged inside the notch.
Then, one end of the central belt 711B is hung on the motor pulley 722B, and the other end is hung on the guide roller 732B inside the notch of the needle plate 12B needle. Further, the two guide rollers 732B on the way function as tension rollers so that the central belt 711B does not loosen.

The guide rollers 733B of the left belt 712B and the right belt 713B are provided at the four corners of the guide frame 731B and form a substantially rectangular belt path surrounding the tip of the sewing machine bed portion 21. Further, the guide roller 733B also includes one that functions as a tension roller arranged so as to press contact with the motor pulley 722B in a state where the left belt 712B and the right belt 713B are not loosened.

On the upper surface of the needle plate 12B, two guide grooves along the X-axis direction are formed on both sides in the Y-axis direction with the needle hole 121B interposed therebetween. The belts 712B and 713B are guided by the guide rollers 733B so as to pass through the two guide grooves of the needle plate 12B.
These guide grooves are formed so that the depth of the grooves is shallower than the thickness of each of the belts 712B and 713B so as to make good contact with the sewn object C placed on the upper surface of the needle plate 12B from the lower side. There is.

With the guide mechanism 73B and the needle plate 12B, the central belt 711B is in contact with the sewn object C on the needle plate 12B from below on the downstream side in the feed direction of the needle hole 121B, which is the needle drop position. Send.
Further, the left belt 712B and the right belt 713B are sewn objects C on the needle plate 12B in a range extending from the upstream side to the downstream side in the feed direction with respect to the needle hole 121B on both the left and right sides of the needle hole 121B which is the needle drop position. The sewn object C is fed in a state of being in contact with the sewn material C from below.

The rotational operation of the lower feed motor 72B is also controlled by the control device 90. In this case, in principle, the lower feed motor 72B is controlled so that the feed motor 52 of the upper belt mechanism 50 and the feed speed of the sewn object C are equal to each other.
However, adjustment control is performed to increase or decrease the rotation speed of the lower feed motor 72B separately from the feed motor 52 so that the feed speed differs between the upper portion and the lower portion of the sewn object C. It may be configured so that
When controlling the feed rate of the lower feed motor 72B independently, the feed rate of the lower feed motor 72B is input from the operation panel 91, or the speed difference or speed ratio with respect to the feed rate of the upper belt mechanism 50 is input. ..
Further, as in the case of the feed motor 52 of the upper belt mechanism 50, the lower feed motor 72B may also be provided with an adjustment dial for inputting an increase or decrease in the feed speed by a rotation operation.

[Technical effect of the second embodiment]
Since the flat stitch sewing machine 10B is provided with the lower belt mechanism 70B, unlike the lower feed mechanism that intermittently feeds the sewn object by the feed dogs in contact with the sewn object C, the belts 711B to 713B always use the belts 711B to 713B for the sewn object. The feed can be performed in contact with the sewn product C. Therefore, the sewn object C can be fed in a state of being always in contact with the belt from above and below, the upper part and the lower part of the sewn object C are less likely to be misaligned, and sewing can be performed with high sewing quality.
Further, since the belts 711B, 712B, and 713B are in contact with the lower side of the sewn object C to feed the sewn object C, the sewn object C having a step or thickness is damaged by the feed dog, unlike the case where the sewn object C is fed by the feed dog. And indentations can be reduced.

Further, the central belt 711B is arranged so that the position in contact with the object to be sewn C and the needle drop position (needle hole 121B) are lined up along the X-axis direction, and the center belt 711B is located on the downstream side in the feed direction (needle drop position) with respect to the needle drop position. It is arranged so as to be in contact with the sewn object C on the front side).
Therefore, the delay in feeding the sewn object C by the sewing needle 11 can be reduced, and the sewn object C can be fed more satisfactorily as a whole.
Further, since the left belt 712B and the right belt 713B are arranged on both sides of the central belt 711B in the Y-axis direction, the three belts 711B to 713B make it possible to perform feed with further excellent straightness. ..

The lower belt mechanism 70B also has two lower feed motors as in the upper belt mechanism shown in FIG. 9, one lower feed motor feeds the center belt 711B and the left belt 712B, and the other lower belt feed. The right belt 713B may be fed by a motor, and the lower belt feed speeds thereof may be individually controlled. Further, one lower feed motor may feed the center belt 711B and the right belt 713B, and the other lower feed motor may feed the left belt 712B, and the lower belt feed speeds thereof may be individually controlled.
Alternatively, the lower belt feed rate may be individually controlled by the central belt 711B, the left belt 712B, and the right belt 713B, which are provided with three lower feed motors.

[others]
In the upper belt mechanisms 50 and 50A, the case where the number of feed belts is three is illustrated, but the number of feed belts may be two. In that case, it is desirable that the feed belt to be deleted is the left belt 512 or the right belt 513.
In this way, even when the feed belt is composed of two, by controlling the speed of the feed motor 52 separately from the sewing machine motor, the difference in feed amount between the upper portion and the lower portion of the sewn object C is reduced. It is possible to do.
Similarly, for the lower belt mechanism 70B, two feed belts (center belt 711B and left belt 712B or center belt 711B and right belt 713B) may be used.

Further, when the left belt 512 (or the left belt 712B) is deleted, it becomes easy to guide the sewn object C so as to be curved to the right, and when the right belt 513 (or the right belt 713B) is deleted, it becomes easier to guide the sewn object C. It becomes easy to guide the object to be sewn C so as to be curved to the left side, and it is possible to easily form a curved seam by hand.

10,10B Flat stitch sewing machine 11 Sewing needle 12, 12B Needle plate 30 Cloth holding mechanism 50, 50A Upper belt mechanism 52 Feed motor 53 Guide mechanism 70B Lower belt mechanism 72B Lower feed motor (feed motor)
90 Control device 91 Operation panel 92 Adjustment dial 311 Holding plate 312 Standing part 313,314 Needle insertion part 351 First left roller 352 Second left roller 353 First right roller 354 Second right roller 355 First center roller 356 Second Central roller 357 Third central roller 511 Central belt (feed belt)
512 Left belt (side belt, feed belt)
513 Right belt (side belt, feed belt)
711B Central belt (feed belt)
712B Left belt (side belt, feed belt)
713B Right belt (side belt, feed belt)
C Sewing object C1 Folded part

Claims (9)

In a flat sewing machine that forms a plurality of stitches along the feed direction of an object to be sewn by a plurality of sewing needles and performs flat stitching by sewing a decorative thread that crosses between the plurality of stitches.
It is provided with an upper belt mechanism equipped with a plurality of feed belts that are in contact with the sewn object on the needle plate from above and feed the sewn object in the feed direction and a feed motor that is a drive source for the feed operation.
A plurality of feed belts of the upper belt mechanism, possess a central belt in contact with the workpiece in the feed direction downstream relative to the needle drop position, and a lateral belt in contact with the workpiece next to the central belt ,
A flat stitch sewing machine characterized in that the bottom portion of the central belt is arranged at a position lower than the bottom portion of the side belt. The central belt is arranged so that the position in contact with the sewn object and the needle drop position are aligned along the feed direction, and is in contact with the sewn object on the downstream side in the feed direction with respect to the needle drop position. The flat stitch sewing machine according to claim 1, wherein the sewing machine is arranged in such a manner. The flat stitch sewing machine according to claim 1 or 2 , wherein the two side belts are arranged on both sides of the central belt. A control device for controlling the feed rate by the feed motor is provided.
The flat stitch sewing machine according to any one of claims 1 to 3 , wherein the control device includes an adjustment dial for setting and inputting a feed speed of the feed motor by a rotation operation. The upper belt mechanism includes two feed motors.
Any one of claims 1 to 4 , wherein one of the plurality of feed belts and the remaining other feed belts are individually driven by the two feed motors. The flat stitch sewing machine described in. The plurality of feed belts are supported so as to be transportable by a pressing plate that presses the object to be sewn from above.
The holding plate is supported so that the upstream end in the feed direction can be raised and lowered with the downstream end in the feed direction as a fulcrum, and the upstream end in the feed direction is elastically supported in the downward direction by an elastic member. The flat stitch sewing machine according to any one of claims 1 to 5, wherein the sewing machine is provided. The plurality of feed belts are supported so as to be transportable by a pressing plate that presses the object to be sewn from above, and are arranged so as to be inclined upward on the downstream side of the pressing plate in the feed direction.
The invention according to any one of claims 1 to 6 , wherein a convex member that is convex on the downstream side in the feed direction with respect to the plurality of feed belts is provided on the downstream side in the feed direction from the holding plate. The flat stitch sewing machine described. The flat stitch sewing machine according to claim 7 , wherein the lower end of the convex member has a shape in which the downstream side in the feed direction is inclined upward. It is provided with a lower belt mechanism equipped with a plurality of feed belts that are in contact with the sewn object on the needle plate from below and feed the sewn object in the feed direction and a feed motor that is a drive source for the feed operation.
The plurality of feed belts of the lower belt mechanism have a central belt that contacts the sewn object on the downstream side in the feed direction with respect to the needle drop position, and a side belt that contacts the sewn object next to the central belt. The flat stitch sewing machine according to any one of claims 1 to 8, wherein the flat sewing machine is characterized.

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