CN107488942B - Flat-seam sewing machine - Google Patents

Abstract

The conveyance is performed in a manner that the speed difference is not generated between the upper side part and the lower side part, and the sewed object is not damaged. A flat-seam sewing machine (10) which forms a plurality of stitches in a feed direction of a material (C) to be sewn by a plurality of sewing needles (11) and performs flat sewing for sewing a decorative thread crossing between the plurality of stitches, the flat-seam sewing machine (10) having an upper feed belt mechanism (50), the upper feed belt mechanism (50) having: a plurality of feeding belts which are contacted with the sewed object on the needle plate (12) from the upper part and convey the sewed object in the feeding direction; and a feed motor (52) serving as a drive source for the feed operation, wherein the plurality of feed belts of the upper feed belt mechanism include: a central feeding belt (511) which is contacted with the sewed object at the downstream side of the feeding direction relative to the needle position; and side feeding belts (512, 513) which are contacted with the sewed object at the adjacent position of the central feeding belt.

Description

Flat-seam sewing machine

Technical Field

The present invention relates to a flat-seam sewing machine.

Background

In a conventional flat-stitch sewing machine, sewing is performed while feeding a cloth held in a state of being held up and down on a needle plate by feed teeth which are advanced from a lower side of the needle plate and a cloth presser foot which presses a material to be sewn on the needle plate from above.

However, since the upper cloth of the overlapped object to be sewn is pressed by the cloth presser foot and the lower cloth is directly contacted with the feed tooth to be fed, a difference in feed amount occurs between the upper and lower cloth, and there is a possibility that the object to be sewn is loosened to cause a decrease in sewing quality.

In order to solve the above-described problems, a case where a feed mechanism of a vertical feed sewing machine is used in a flat-seam sewing machine has been studied.

The vertical feed sewing machine has a structure in which a feed leg portion that reciprocates in a feed direction and a presser foot portion that does not oscillate are alternately moved up and down on the upper side of a needle plate, the feed leg portion oscillates toward the downstream side in the feed direction when the feed leg portion is lowered, and the feed leg portion oscillates toward the upstream side in the feed direction when the presser foot portion is lowered and the feed leg portion is raised (see, for example, patent document 1).

Further, since the feed teeth and the feed leg portion feed the material to be sewn in synchronization with each other, the difference in feed amount between the upper cloth and the lower cloth of the material to be sewn can be reduced.

Patent document 1: japanese laid-open patent publication No. 2010-057906

However, the vertical feed mechanism using the feed leg portion of patent document 1 has a structure in which the workpiece is sandwiched and fed from above and below by the feed teeth and the feed leg portion, and therefore, in the case of a thick workpiece or a stepped workpiece, the sandwiching pressure is increased, and there is a possibility that the workpiece may be damaged.

Disclosure of Invention

The invention aims to provide a flat-seam sewing machine which can perform good conveying.

(1) The invention described is a flat-seam sewing machine,

the flat-seam sewing machine forms a plurality of stitches along the feeding direction of the sewed object through a plurality of sewing needles, and performs flat sewing for sewing in the decorative thread crossing between the plurality of stitches,

the flat-seam sewing machine is characterized in that,

the upper feeding mechanism comprises: a plurality of feeding belts which are contacted with the sewed object on the needle plate from the upper part and convey the sewed object to the feeding direction; and a feed motor serving as a drive source for feeding the plurality of feed belts,

the plurality of feed belts of the upper feed belt mechanism have: a central feeding belt which is contacted with the sewed object at the downstream side of the feeding direction relative to the needle position; and a side feeding belt which is contacted with the sewed object at the adjacent position of the central feeding belt.

(2) The invention described in (1) is characterized in that, in the flat-seam sewing machine,

the central feeding belt is configured to be arranged along the feeding direction at a position contacting with a sewed object and the needle drop position, and is configured to contact with the sewed object at the downstream side of the feeding direction relative to the needle drop position.

(3) The invention described in (1) or (2) is characterized in that, in the flat-seam sewing machine,

the bottom of the center feed belt is disposed at a lower position than the bottom of the side feed belt.

(4) The invention described in (1) to (3) is characterized in that, in the flat-seam sewing machine,

the two side feed belts are disposed on both sides of the center feed belt with the center feed belt interposed therebetween.

(5) The invention described in (1) to (4) is characterized in that, in the flat-seam sewing machine,

having a control device for controlling the feed speed by the feed motor,

the control device is provided with an adjusting disc, and the adjusting disc performs setting input on the feeding speed of the feeding motor through rotation operation.

(6) The invention described in (1) to (5) is characterized in that, in the flat-seam sewing machine,

the upper feed belt mechanism has two of the feed motors,

one of the side feed belts and the remaining other feed belts are driven by the two feed motors independently.

(7) The invention described in (1) to (6) is characterized in that, in the flat-seam sewing machine,

the plurality of feeding belts are supported by a presser foot plate which can press the sewed object from the upper part in a conveying way,

the presser foot plate is supported so as to be able to move up and down an upstream end portion in the feeding direction with a downstream end portion in the feeding direction as a fulcrum, and an elastic force is applied to the upstream end portion in the feeding direction in a downward direction by an elastic member.

(8) The invention described in (1) to (7) is characterized in that, in the flat-seam sewing machine,

the plurality of feed belts are arranged to be supported by a presser foot plate that presses the sewing object from above so as to be conveyable, and are inclined upward on a downstream side in the feed direction of the presser foot plate,

the flat-stitch sewing machine includes a convex member that protrudes downstream in the feeding direction with respect to the plurality of feeding belts on a downstream side in the feeding direction with respect to the presser foot plate.

(9) The invention described in (8) is characterized in that, in the flat-seam sewing machine,

the lower end of the convex member is inclined upward on the downstream side in the feeding direction.

(10) The invention described in (1) to (9) is characterized in that, in the flat-seam sewing machine,

having a lower feed belt mechanism having: a plurality of feeding belts which are contacted with the sewed object on the needle plate from the lower part and convey the sewed object to the feeding direction; and a feed motor serving as a drive source for feeding the plurality of feed belts,

the plurality of feed belts of the lower feed belt mechanism have: a central feeding belt which is contacted with the sewed object at the downstream side of the feeding direction relative to the needle position; and a side feeding belt which is contacted with the sewed object at the adjacent position of the central feeding belt.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the above configuration of the present invention, since the feed motor is provided, the feed amount can be adjusted independently for the upper side portion and the lower side portion of the workpiece, and since the feed belt is brought into contact with the workpiece, the occurrence of damage can be reduced even for a workpiece having a step or a thick workpiece.

Drawings

Fig. 1 is a perspective view of a flat-seam sewing machine as a first embodiment.

Fig. 2 is an oblique view of the periphery of the needle drop position of the flat-seam sewing machine.

Fig. 3 is a side view of the cloth presser mechanism and the upper feed belt mechanism.

Fig. 4 is a perspective view of the lower end portions of the cloth presser mechanism and the upper feed belt mechanism.

Fig. 5 is an oblique view of the cloth presser foot.

Fig. 6 is a front view of a presser foot plate of the cloth presser foot.

Fig. 7 is an enlarged oblique view of the cloth presser foot.

Fig. 8 is a side view of the cloth presser foot.

Fig. 9 is a side view of another example of an upper feed belt mechanism having two feed motors.

Fig. 10 is a perspective view of the periphery of a needle plate of a flat-seam sewing machine as a second embodiment.

Fig. 11 is a perspective view of a lower feed belt mechanism mounted on the flat-seam sewing machine.

Fig. 12 is a side view of the lower feed belt mechanism.

Description of the reference numerals

10. 10B flat seam sewing machine

11 stitch

12. 12B needle board

30 cloth presser foot mechanism

50. 50A upper feeding belt mechanism

52 feed motor

53 guide mechanism

70B lower feeding belt mechanism

72B lower feed motor (feed motor)

90 control device

91 operating panel

92 adjusting disk

311 foot pressing plate

312 upright setting part

313. 314 needle insertion portion

351 first left roller

352 second left roll

353 first right roller

354 second right roller

355 first center roll

356 second center roller

357 third central roll

511 center feed belt (feed belt)

512 left feeding belt (side feeding belt, feeding belt)

513 Right feeding belt (side feeding belt, feeding belt)

711B center feeding belt (feeding belt)

712B left feeding belt (side feeding belt, feeding belt)

713B Right feeding belt (side feeding belt, feeding belt)

C quilt sewing material

C1 folded back part

Detailed Description

[ schematic configuration of the first embodiment ]

A flat-seam sewing machine 10 as a first embodiment will be described with reference to fig. 1 to 8.

Fig. 1 is an oblique view of the flatseam sewing machine 10, and fig. 2 is an oblique view of the periphery of the needle drop position of the flatseam sewing machine 10.

In the following description, one horizontal direction is defined as an X-axis direction, a direction horizontal and orthogonal to the X-axis direction is defined as a Y-axis direction, and a vertical direction is defined as a Z-axis direction. As shown in fig. 1, the following description will be made with one in the X-axis direction being "front", the other being "rear", one in the Y-axis direction being "left", and the other being "right".

The flat-seam sewing machine 10 includes: a sewing machine frame 20; a needle up-down moving mechanism, not shown, for moving the two needles 11 up and down using a sewing machine motor as a driving source; a lower looper mechanism, not shown, which reciprocates the lower looper using a sewing machine motor as a drive source and inserts a lower looper thread into a thread loop of the upper thread of the two sewing needles, on the lower side of the needle plate 12; a not-shown thread puller mechanism that guides the upper decorative thread so that the upper decorative thread is sewn in the Y-axis direction to two stitches formed by the two sewing needles 11; a lower feed mechanism, not shown, which advances and retracts the feed teeth from the lower side of the needle plate 12 and conveys the sewed object to the downstream side of the feed direction along the X-axis direction; a cloth presser mechanism 30 for pressing the material to be sewn from above by a cloth presser 31; an upper feed belt mechanism 50 for conveying the feed belt from above to the downstream side (front) of the feed direction by contacting the feed belt with the sewing object on the needle plate 12; a cloth cutting mechanism 80 for cutting off the end of the folded sewed object; a wire adjuster mechanism 13; a scale mechanism 14; and a control device 90 that performs control of the above-described respective configurations.

[ Sewing machine frame ]

The sewing machine frame 20 has: a sewing machine base part 21 extending in the Y-axis direction at the lower part of the flat-seam sewing machine 10; a longitudinal body part 22 provided upright from one end of the sewing machine base part 21; and a sewing machine arm 23 extending from an upper end of the longitudinal body 22 in the same direction as the sewing machine bed 21.

A needle plate 12 is provided on an upper surface of an end portion of the sewing machine base portion 21 opposite to the longitudinal machine body portion 22, and two sewing needles 11 are dropped into a needle hole formed in the needle plate 12.

[ Up-and-down moving mechanism of sewing needle ]

The needle up-and-down moving mechanism comprises: a needle bar 15 (see fig. 3) supported at a distal end portion of the sewing machine arm 23 so as to be movable up and down in the Z-axis direction; two sewing needles 11 held at the lower end of the needle bar 15; and a crank mechanism for applying the vertical movement action to the needle bar 15 from the sewing machine motor.

The needle bar 15 holds two sewing needles 11 at the lower end thereof in a state of being arranged in the Y-axis direction.

In the flat-seam sewing machine 10, a material to be sewn is conveyed forward in the X-axis direction, and two stitches aligned in the Y-axis direction are formed in the X-axis direction by two sewing needles 11.

[ line regulator mechanism and balance mechanism ]

The flat-seam sewing machine 10 performs sewing by two upper threads, a lower looper thread, and an upper decorative thread, and the thread adjuster mechanism 13 is composed of a plurality of thread adjusters that apply thread tension to the respective threads.

The thread take-up mechanism 14 has a swing type thread take-up which inserts two upper threads to which thread tension is applied in the thread adjuster mechanism 13. The balance receives power of swing from a sewing machine motor, swings in synchronization with the vertical movement of the sewing needle 11, and lifts each upper thread at an appropriate timing.

[ lower looper mechanism ]

The lower looper mechanism has: a lower looper disposed inside the base part 21 of the sewing machine and reciprocating forward and backward along the Y-axis direction; and a transmission mechanism for applying forward and backward movement to the lower looper from the sewing machine motor.

The lower looper is a sharp member projecting leftward in the Y axis direction, and is disposed below the needle plate 12, and has a threading hole for inserting a lower looper thread formed at a distal end thereof. When the needle thread is advanced in the left direction, the needle thread enters the loops of the upper thread passing through the two lowered needles 11, and the lower looper thread can be inserted into the loops of the two upper threads.

Further, the two lowered sewing needles 11 enter into loops of the lower looper thread formed when the lower looper retreats rightward, and two upper threads are inserted. By repeating these actions alternately, two stitches in the X-axis direction are formed.

[ wire grip mechanism ]

The wire grip mechanism comprises: a wire grip which is arranged above the needle plate and guides the upper decoration wire through the front end part; and a rotating mechanism which applies a rotating action to make the front end part of the wire puller reciprocate along the Y-axis direction.

The rotation mechanism applies a reciprocating rotation motion of the thread puller in synchronization with the vertical movement of the needle 11 by using a sewing machine motor as a driving source.

The upper decorative thread guided by the thread puller swings left and right in synchronization with the needle fall of the two sewing needles 11, and can be alternately sewn into the two stitches formed on the object to be sewn.

[ lower feed mechanism ]

The lower feeding mechanism comprises: feed teeth for advancing the tooth tips from the opening of the needle plate 12; and a revolving mechanism that revolves the feed teeth in an oblong track in the X-axis direction.

The revolving mechanism has a horizontal feed shaft and an up-and-down feed shaft which are reciprocated by using a sewing machine motor as a drive source, and applies up-and-down reciprocating motion and reciprocating motion in an X-axis direction to a feed table supporting feed teeth, thereby applying an oblong revolving motion to the feed teeth.

When the feed teeth pass through the upper part of the long circular track, the tooth tops protrude upwards from the opening part of the needle plate, and at the moment, the feed teeth move forwards. Therefore, the tooth tops contact the sewed object on the needle plate from the lower side, and the sewed object can be intermittently conveyed forwards at a fixed feeding interval.

[ cloth cutting mechanism ]

The material to be sewn C is a cloth folded with the right edge portion folded downward, and the cloth cutting mechanism 80 cuts the leading end portion of the folded portion of the material to be sewn C so as to align the Y-axis direction width of the folded portion at a constant value on the upstream side in the cloth feeding direction from the needle drop position.

As shown in fig. 2, the cloth cutting mechanism 80 includes: a positioning scale 81 which abuts against a right edge portion of the folded portion C1 (see fig. 5) of the object C to be sewn at the time of sewing; a fixed knife 82 and a movable knife 83 which cut off the left edge part folded back at the lower side of the sewed object C; and a cutter up-down moving mechanism that moves the movable cutter 83 up and down.

The positioning scale 81 is a flat plate-like member along the X-Z plane, and abuts against the folded line portion (right edge portion) of the workpiece C on the left plane thereof. The positioning scale 81 can adjust the position in the Y-axis direction, and thus can adjust the Y-direction width of the folded portion of the workpiece C.

The fixed knife 82 is disposed with the cutting edge facing upward, and the movable knife 83 is lowered toward the cutting edge of the fixed knife, so that the left folded edge of the workpiece C passing between the fixed knife 82 and the movable knife 83 can be cut off.

The cutter vertical movement mechanism has a drive shaft that reciprocates using a sewing machine motor as a drive source, and supports the movable cutter 83 by the tip of the drive shaft. The movable knife 83 is reciprocated and rotated, so that the distal end portion thereof is moved up and down to cut the workpiece C.

[ cloth presser foot mechanism ]

Fig. 3 is a side view of the cloth presser mechanism 30 and the upper feed belt mechanism 50, fig. 4 is an oblique view of the lower end portions of the cloth presser mechanism 30 and the upper feed belt mechanism 50, and fig. 5 is an oblique view of the cloth presser 31.

As shown in fig. 2 to 5, the cloth presser mechanism 30 includes: a cloth presser foot 31; a presser bar 32 for supporting the cloth presser 31 at a lower end portion thereof; a cylinder 33 for applying a presser foot pressure to the cloth presser foot 31; and a manual presser foot pressure release mechanism 34.

The presser bar 32 is supported by the front end of the arm 23 of the sewing machine so as to be movable up and down, and the upper end thereof is connected to a plunger of the cylinder 33. Further, by the operation of the air cylinder 33, the application of the presser foot pressure to the workpiece C by the cloth presser foot 31 and the release of the presser foot pressure by the raising of the cloth presser foot 31 can be switched.

Two valves 331 and 332 for supplying air pressure and air from an external air pressure source are provided in the cylinder 33, and a low pressure (for example, 2 kgf/cm) is supplied to one valve 331 from the external air pressure source via a pressure reducing valve (not shown)²) The other valve 332 is supplied with high pressure (e.g., 4 kgf/cm) from an external air pressure source without passing through a pressure reducing valve²) Of the air of (2).

Each of the valves 331 and 332 has a manual button 333 and 334 for switching between supply and stop of air, and the intensity of the presser foot pressure of the cloth presser foot 31 can be switched by switching operation of the buttons 333 and 334.

As shown in fig. 3, the presser foot pressure release mechanism 34 includes: a bar holding portion 341 fixedly provided to the presser bar 32; an input shaft 342 connected to a manual presser foot raising lever, not shown; a rotating arm 343 fixedly attached to the input shaft 342; and a link member 344 that couples the pivot end of the pivot arm 343 and the bar holding portion 341.

With this configuration, if the presser foot raising lever is manually rotated counterclockwise, the rotating end of the rotating arm 343 is rotated upward via the input shaft 342, and the presser bar 32 and the cloth presser foot 31 can be raised via the link member 344.

As shown in fig. 3 to 8, the cloth presser 31 includes: a footpad 311; and an upright setting portion 312 provided at the front center of the footpad 311. In fig. 5, illustration of the upright setting portion 312 is omitted.

A coupling hole into which the lower end of the presser bar 32 can be inserted is provided at the upper end of the upright portion 312, and the presser bar 32 can be held by a grub screw.

The presser foot plate 311 has a function of applying the presser foot pressure from the cylinder 33 to the workpiece C, and two needle insertion portions 313 and 314 penetrating vertically are formed at the center portion of the presser foot plate 311. The needle is dropped onto the workpiece C below the presser foot 311 by the two sewing needles 11 and 11 through the needle insertion portions 313 and 314.

The presser foot 311 also has a function of guiding the center feed belt 511, the left feed belt 512, and the right feed belt 513, which are three feed belts of the upper feed belt mechanism 50 described later, so as to be conveyable in the feed direction, from the upper surface thereof to the bottom surface via the rear end portion or a position slightly forward of the rear end portion.

Therefore, the first left roller 351 and the second left roller 352 for conveying the left feed belt 512 are rotatably disposed at the left rear end portion and the left front end upper portion of the presser foot plate 311.

Further, a first right roller 353 and a second right roller 354 for conveying the right feed belt 513 are rotatably disposed at the right rear end portion and the right front end upper portion of the footpad 311.

Further, a large notch is formed from the front end portion to the center portion of the presser foot plate 311, and a first center roller 355 and a second center roller 356 for conveying the center feed belt 511 are arranged in the front-rear direction so as to be rotatable. The third center roller 357 is rotatably disposed at the center front end upper portion of the footpad 311.

Further, the second left roller 352, the second right roller 354, and the third center roller 357 are not supported by the footpad 311, but are supported by the upright setting portion 312.

The center feed belt 511, the left feed belt 512, and the right feed belt 513 can be smoothly conveyed by the rollers 351 to 357 in a state of being aligned in the Y axis direction and directed forward on the bottom surface of the presser foot plate 311, and can be brought into contact with the upper surface of the workpiece C by the presser foot pressure of the presser foot plate 311 and feed out the upper surface of the workpiece C forward.

First center roller 355 is disposed in parallel with needle insertion portions 313 and 314, which are needle drop positions, in the X-axis direction (feeding direction), and is disposed forward (downstream in the feeding direction) of needle insertion portions 313 and 314.

On the other hand, first left roller 351 and first right roller 353 are located on the left and right sides of needle insertion portions 313 and 314, and are arranged further rearward (upstream side in the feeding direction) than needle insertion portions 313 and 314.

Thus, the center feed belt 511 is conveyed in contact with the workpiece on the downstream side in the feeding direction from the needle position, and the left feed belt 512 and the right feed belt 513 are conveyed in contact with the workpiece on the upstream side in the feeding direction from the needle position.

As shown in fig. 6, the bottoms of the center feed belt 511, the left feed belt 512, and the right feed belt 513, which are in contact with the workpiece C, are supported at different heights. That is, the bottom of the center feed belt 511 is supported to be the lowest position, the bottom of the left feed belt 512 is the next lowest position, and the bottom of the right feed belt 513 is the highest position.

The height of the bottom of the center feed belt 511 is adjusted by the installation heights of the first center roller 355 and the second center roller 356, and the heights of the bottoms of the left feed belt 512 and the right feed belt 513 are adjusted by the depths of grooves 311a and 311b formed on the bottom surface side of the presser foot plate 311 for guiding the respective feed belts.

Therefore, the central feed belt 511 is in the closest pressure-contact state with the workpiece C with respect to the central portion where resistance is likely to be generated to feed due to needle fall, and therefore, a delay with respect to the left and right is suppressed, and the workpiece C can be stably conveyed.

Further, when the right edge of the material to be sewn C is folded back and sewn, the folded-back portion C1 is not present on the left side of the needle drop position, and the material to be sewn on the left side is substantially thinner than the right side of the needle drop position, and therefore, the bottom of the left feed belt 512 is disposed at a lower position than the bottom of the right feed belt 513, so that the left feed belt 512 and the right feed belt 513 can be pressed against the material to be sewn with good left-right balance, and the material to be sewn C can be conveyed stably without being deviated left-right.

As shown in fig. 7, the tip end portion (the downstream end portion in the feeding direction) of the presser foot plate 311 is pivotally supported on a fulcrum shaft (not shown) so as to be swingable about the Y axis with respect to the upright portion 312. Thus, the rear end portion (the upstream end portion in the feeding direction) of the presser foot plate 311 swings about a fulcrum shaft (not shown) provided at the downstream end portion in the feeding direction of the presser foot plate 311 as a fulcrum, and can be lifted up and down.

A torsion coil spring 316 as an elastic member is provided on the left side surface of the leg pressing plate 311 by a stepped screw 315, one end of the torsion coil spring 316 is locked to the upright portion 312 side, and the other end is pressed against the upper surface of the rear end of the leg pressing plate 311. Thereby, the presser foot plate 311 is in a state of being applied with a downward elastic force to the rear end portion thereof.

In addition, in FIG. 7, the feeding belts 511 to 513 and the rollers 351 to 357 are not shown.

Since the presser foot 311 is pressed downward by the air cylinder 33 via the presser foot bar 32, the bottom surface of the presser foot 311 is kept horizontal during normal sewing, and the object to be sewn C is pressed.

However, since the presser foot 311 is swingable relative to the upright installation section 312 as described above, if the workpiece C has a stepped portion which is conveyed from the rear to the front, the rear end portion of the presser foot 311 is swung upward against the torsion coil spring 316 and easily goes over the stepped portion, and smooth and satisfactory conveyance can be performed even for the workpiece C having the stepped portion.

As shown in fig. 8, the center feed belt 511, the left feed belt 512, and the right feed belt 513 are extended from the front end portion (the downstream end portion in the feed direction) of the presser foot plate 311 of the cloth presser 31 in the forward oblique upward direction at substantially the same inclination angle.

Further, a convex member 317 is formed at a front end portion (end portion on the downstream side in the feeding direction) of the upright portion 312 of the cloth presser 31 and at a position forward of the front end portion of the presser foot plate 311. The male member 317 extends obliquely upward when viewed from the side, and projects forward from the center feed belt 511, the left feed belt 512, and the right feed belt 513.

The male member 317 has a downward inclined surface 317a inclined forward and upward from substantially the same position as the front end portion of the bottom surface of the footpad 311 when viewed from the side. The inclined surface 317a is inclined upward at a gentle angle compared to the feed belts 511, 512, and 513. Therefore, the male member 317 is projected forward and downward from the feed belts 511, 512, and 513 when viewed from the side.

If the convex member 317 is not present, the sewn object C conveyed forward by the feed belts 511, 512, 513 is likely to be loosened so as to protrude upward in front of the bottom surface front end portion of the presser foot plate 311. If such a slack occurs, the good feeding operation of the workpiece C is hindered, and therefore, the operator of the sewing machine needs to sew the workpiece C while stretching the workpiece C forward so that the slack does not occur.

However, by providing the convex member 317 at the front end portion of the cloth presser foot 31, the space in which the object C to be sewn loosens ahead of the bottom surface front end portion of the presser foot plate 311 disappears, and the occurrence of looseness can be suppressed.

Further, since the lower portion of the convex member 317 has the shape having the inclined surface 317a, the object C can be conveyed forward satisfactorily while eliminating slack. Thus, the operator of the sewing machine does not need to perform the operation of stretching the object C forward, and the operability during sewing can be improved.

Further, the lower portion of the male member 317 exemplifies the inclined surface 317a inclined straight forward, but the shape is not limited thereto. For example, the lower portion of the convex member 317 may have a curved surface that gradually rises while being curved from a state in which the lower portion is level with the bottom surface of the leg pressing plate 311.

The convex member 317 may be formed integrally with the upright portion 312 of the cloth presser 31 or may be formed as a separate member.

[ Upper feed belt mechanism ]

The upper feed belt mechanism 50 includes: a center feed belt 511, a left feed belt 512, and a right feed belt 513 in an endless loop shape as a plurality of feed belts; a feed motor 52 serving as a drive source for feeding the feed belt; and a guide mechanism 53 for guiding the feed belts 511-513 from the feed motor 52 to the cloth presser 31.

The feed motor 52 is a motor capable of controlling the rotation speed, and 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 side of the front end portion of the sewing machine arm 23 via the motor bracket 521 in a state where the output shaft is directed leftward.

An output shaft of the feed motor 52 is provided with a motor pulley 522 that winds one end of each of the feed belts 511 to 513.

The guide mechanism 53 is mainly composed of: a guide arm 533 constituted by the first and second link members 531, 532; and a plurality of guide rollers 534 rotatably provided at each portion of the feed belt path from the motor pulley 522 to the cloth presser foot 31.

The first link member 531 of the guide arm 533 has one end portion coupled to the lower portion of the motor bracket 521 so as to be rotatable about the Y axis, and has the other end portion coupled to one end portion of the second link member 532 so as to be rotatable about the Y axis.

The other end of the second link member 532 is coupled to a fastening member 535 so as to be rotatable about the Y axis, and the fastening member 535 is fastened to the lower end of the presser bar 32 by being held on the cloth presser 31.

Each of the first link member 531 and the second link member 532 has a pair of left and right plate-like side wall portions extending along the X-Z plane, and the side wall portions face each other. Further, the guide rollers 534 are disposed at respective positions on the opposing surfaces of the opposing side wall portions of the respective link members 531, 532, whereby the feed belt paths of the respective feed belts 511 to 513 are formed along the respective link members 531, 532 of the guide arm 533.

The guide rollers 534 are disposed at respective positions of the motor bracket 521 in addition to the respective link members 531, 532.

Each guide roller 534 is disposed at a corner of a predetermined feed belt path, and includes a structure that functions as a tension roller disposed in a pressure contact state so that slack does not occur in each feed belt 511 to 513 in addition to a structure that is disposed at a corner of the path.

One end of each of the feed belts 511 to 513 is wound around a motor pulley 522, passes through each of the guide rollers 534, and the other end is wound around each of the rollers 351 to 357 provided in the cloth presser 31.

Thus, if the feed motor 52 is driven, the feed belts 511 to 513 are conveyed forward on the bottom surface side of the cloth presser foot 31 by the torque thereof.

In addition, the rotation speed of the feed motor 52 is controlled so that the conveying speed of each of the feed belts 511 to 513 on the bottom surface of the cloth presser 31 is made to coincide with a virtual feed speed obtained by averaging intermittent feed speeds by the lower feed mechanism and converting the averaged feed speeds into a continuous feed speed in principle.

However, when a speed difference occurs in the feed speed of the upper portion and the lower portion of the workpiece C, adjustment control is performed to increase or decrease the rotation speed of the feed motor 52.

Further, when the cloth presser 31 is released from the presser pressure, the cloth presser 31 is moved up to the upper retracted position via the presser bar 32, and therefore the other end portion of the second link member 532 of the guide arm 533 is moved upward together with the presser bar 32, but both end portions of the guide arm 533 are coupled to be rotatable about the Y axis, and the first link member 531 and the second link member 532 are also coupled to be rotatable about the Y axis, and therefore the folding angle changes between the first link member 531 and the second link member 532, and the cloth presser 31 can be handled for the lifting.

[ control device ]

The control device 90 is a control circuit having a CPU, a RAM, a data memory, and the like, and is connected to a sewing machine motor, the feed motor 52, and the like via a driver circuit, and can control the start and stop of the driving, the driving speed, and the like.

Further, an operation panel 91 and an adjustment dial 92 shown in fig. 1 are connected to the control device 90 via an interface not shown.

The operation panel 91 includes: an input unit such as a button and a key for inputting various settings related to sewing; and a display unit that performs display for assisting the setting operation.

For example, the rotational speed of the motor of the sewing machine, the feed speed of the workpiece by the upper feed belt mechanism 50, the start of sewing, and the like are input from the operation panel 91.

The feed speed of the workpiece by the upper feed mechanism 50 is not limited to a direct speed, and may be, for example, a speed difference or a speed ratio input with respect to the feed speed of the lower feed mechanism.

In the setting of the various numerical values, for example, an increase/decrease key is used to input an increase/decrease of the set value displayed on the display unit, and the set value is determined by the determination key.

The dial 92 is capable of performing a rotational input operation, and detects an input amount by a rotational amount detection sensor such as a built-in encoder, and inputs the input amount to the control device 90.

The adjustment dial 92 is an input means dedicated to input adjustment of the feed speed of the top feed belt mechanism 50, and inputs an increase in the set value of the feed speed of the top feed belt mechanism 50 by forward rotation and an decrease in the set value of the feed speed by reverse rotation.

The increase or decrease of the set value of the feed speed input from the adjustment dial 92 may be reflected in the speed control of the feed motor 52 in real time during the rotation operation, or may be reflected in the speed control of the feed motor 52 by a decision input operation such as a decision key after the set value is input by the rotation operation of the adjustment dial 92. In the case of an input operation for determination by a determination key or the like, if a push-in operation or a click operation can be performed on the dial of the dial 92 by using the determination key of the operation panel 91, determination may be performed by the push-in operation or the click operation.

[ technical effects of the first embodiment ]

The flat-seam sewing machine 10 includes: a feed motor 52 serving as a drive source for feeding the workpiece C; and an upper feeding belt mechanism 50 having a center feeding belt 511 contacting the workpiece C at a downstream side in a feeding direction with respect to the needle drop position, a left feeding belt 512 contacting the workpiece C at a left adjacent position of the center feeding belt 511, and a right feeding belt 513 contacting the workpiece C at a right adjacent position of the center feeding belt 511, so that a difference in feeding amount between an upper side portion and a lower side portion of the workpiece C can be reduced by controlling a speed of the feeding motor 52 independently of a sewing machine motor.

Further, since the feed belts 511, 512, and 513 are conveyed in contact with the upper side of the workpiece C, unlike the case of feeding the workpiece C sandwiched by the feed teeth from the upper and lower sides, even in the case of the workpiece C having a step or thickness, it is possible to reduce the occurrence of damage or indentation due to the sandwiching pressure.

The center feed belt 511 is arranged such that a position in contact with the workpiece C and a needle drop position are aligned in the X-axis direction, and is arranged in contact with the workpiece C on the downstream side (front side) in the feed direction with respect to the needle drop position.

Therefore, although resistance is generated in a state where the sewing needle 11 penetrates the material to be sewn and delay in the conveyance of the material to be sewn C is more likely to occur than in the left and right sides, the central feed belt 511 is disposed in contact with the downstream side in the feed direction of the needle drop position, and thereby the material to be sewn C can be conveyed in a stretched manner, so that delay in the central portion is reduced and the material to be sewn C can be conveyed in a good entirety.

Further, since the bottom of the center feed belt 511 is disposed at a lower position than the bottom of the left feed belt 512 and the bottom of the right feed belt 513, the center feed belt 511 comes into the closest pressure contact state with the workpiece C with respect to the center portion where resistance is likely to be generated to feed due to needle drop, and therefore, delay with respect to the left and right is suppressed, and the workpiece can be stably conveyed.

Further, since the left feed belt 512 and the right feed belt 513 are disposed on both sides in the Y-axis direction with the center feed belt 511 interposed therebetween, the conveyance can be performed with excellent linearity by the three feed belts 511 to 513.

Further, since the flat-seam sewing machine 10 includes the control device 90 for controlling the feed speed by the feed motor 52, the ratio of the feed amount by the upper feed belt mechanism 50 to the lower feed mechanism can be arbitrarily adjusted, and the sewing quality can be improved by properly conveying the workpiece C in a balanced manner at the upper side portion and the lower side portion.

Further, since the control device 90 includes the adjustment dial 92, the feed amount of the lower feed mechanism can be adjusted with high operability, and since the adjustment work can be performed intuitively, the adjustment can be performed freely even during sewing.

The presser foot plate 311 of the cloth presser 31 of the cloth presser mechanism 30 is supported so as to be able to move up and down the upstream end portion in the feeding direction with the downstream end portion in the feeding direction as a fulcrum, and the upstream end portion in the feeding direction is urged downward by the torsion coil spring 316 with an elastic force.

Therefore, even when the workpiece C has a stepped portion or when the workpiece C has a portion with a varying thickness, the upstream end of the presser foot 311 in the feed direction can be raised and lowered to maintain a state of close contact with the workpiece C, and a variation in the feed amount can be suppressed to perform a stable feed operation.

Further, a convex member 317 protruding to the downstream side in the feeding direction with respect to the plurality of feeding belts 511 to 513 is provided on the downstream side in the feeding direction of the cloth presser 31 of the cloth presser mechanism 30 with respect to the presser foot plate 311.

This eliminates the space in which the object C slacks forward of the bottom surface front end portion of the presser foot plate 311, and thus, the slacks can be suppressed.

Further, since the lower portion of the convex member 317 has the inclined surface 317a, the object C to be sewn can be fed forward well while the slack is eliminated, and the operator of the sewing machine does not need to perform the operation of pulling the object C forward, thereby improving the workability at the time of sewing.

[ other examples of the upper feed belt mechanism ]

Fig. 9 shows another example of the upper feed belt mechanism. The upper feed mechanism 50A is different from the upper feed mechanism 50 described above in that two feed motors 52 are provided, and other points are substantially the same. Therefore, in the upper feed belt mechanism 50A, the same components as those of the upper feed belt mechanism 50 are denoted by the same reference numerals, and redundant description thereof is omitted.

The upper feed mechanism 50A includes a motor bracket 521A that supports two feed motors 52, 52 arranged in the vertical direction, and the motor bracket 521A is attached to the sewing machine arm 23 at the same position as the motor bracket 521 described above.

Each of the output shafts of the feed motors 52 is provided with a motor pulley 522, and only the left feed belt 512 is wound around the motor pulley 522 of the upper feed motor 52, and the center feed belt 511 and the right feed belt 513 are wound around the motor pulley 522 of the lower feed motor 52.

Alternatively, the left feed belt 512 and the center feed belt 511 may be wound around the motor pulley 522 of the upper feed motor 52, and only the right feed belt 513 may be wound around the motor pulley 522 of the lower feed motor 52.

As described above, by configuring such that the left feed belt 512 and the right feed belt 513 are conveyed by the different feed motors 52, the feed speeds of the two feed motors 52 and 52 are controlled to be different from each other, so that the feed direction of the workpiece C can be controlled to be bent to the right or left, and the sewing with the bent to the right or left can be easily and satisfactorily performed. In addition, by setting the difference in the feeding speed between the two feeding motors 52, 52 arbitrarily, the curvature of bending rightward or leftward can be controlled.

The setting of the difference in the feed speeds of the two feed motors 52, 52 is preferably performed by the input operation of the operation panel 91 described above.

Further, another adjustment dial similar to the adjustment dial 92 described above may be provided, and the feed speed difference between the two feed motors 52, 52 can be set and inputted by forward rotation or reverse rotation of the new adjustment dial.

Further, three feed motors may be provided, and the feed speed of the feed belt may be controlled individually for each of the center feed belt 511, the left feed belt 512, and the right feed belt 513.

[ second embodiment ]

A flat-seam sewing machine 10B as a second embodiment will be described with reference to fig. 10 to 12.

Fig. 10 is a perspective view of the periphery of a needle plate of the flat-seam sewing machine 10B, fig. 11 is a perspective view of a lower feed belt mechanism 70B mounted on the flat-seam sewing machine 10B, and fig. 12 is a side view of the lower feed belt mechanism 70B.

In the flat-seam sewing machine 10B, one horizontal direction is defined as an X-axis direction, a direction horizontal and orthogonal to the X-axis direction is defined as a Y-axis direction, and a vertical direction is defined as a Z-axis direction. As shown in fig. 1, the following description will be made with one in the X-axis direction being "front", the other being "rear", one in the Y-axis direction being "left", and the other being "right".

The flat-seam sewing machine 10B is different from the flat-seam sewing machine 10 in that a lower feed belt mechanism 70B that feeds the workpiece C on the needle plate 12B from below is provided instead of the lower feed mechanism described above.

Therefore, in the following description, the same components as those of the flat-seam sewing machine 10 are denoted by the same reference numerals, and the description thereof will be omitted, and the lower feed belt mechanism 70B will be mainly described.

[ lower feed belt mechanism ]

The lower feed belt mechanism 70B includes: a center feed belt 711B, a left feed belt 712B, and a right feed belt 713B in an endless loop shape as a plurality of feed belts; a lower feed motor 72B as a feed motor, which serves as a drive source for feeding the feed belt; and a guide mechanism 73B that guides the feed belts 711B to 713B on a path from the lower feed motor 72B through the needle plate 12B.

The lower feed motor 72B is a motor capable of controlling the rotation speed, and for example, a dc motor, an ac motor, a stepping motor, or the like is used.

The lower feed motor 72B is fixedly attached to the front surface side of the front end portion of the sewing machine bed portion 21 via a motor bracket 721B in a state where the output shaft is directed rightward.

Further, a motor pulley 722B that winds a part of each of the feed belts 711B to 713B is provided on an output shaft of the lower feed motor 72B.

The guide mechanism 73B includes: a guide frame 731B that guides the feed belts 711B to 713B; a plurality of guide rollers 732B that form a feed belt path of the center feed belt 711B from the motor pulley 722B to the needle plate 12B; and a guide roller 733B provided on the guide frame 731B and configured to support the left feed belt 712B and the right feed belt 713B so as to be conveyable so as to make a single round along the outer periphery of the sewing machine base 21.

The guide frame 731B is a substantially rectangular frame body when viewed from the Y axis direction, and is mounted on the sewing machine base portion 21 so as to surround the front end portion of the sewing machine base portion 21.

The upper portion of the guide frame 731B is coupled to the needle plate 12, and the feed belts 711B to 713B supported by the guide frame 731B can be guided on the upper surface of the needle plate 12B.

The guide roller 732B of the center feed belt 711B is provided at the following position: at a position between the motor pulley 722B and the needle plate 12B; and a position near needle hole 121B of needle plate 12B and on the downstream side in the feeding direction of needle hole 121B.

The needle plate 12B has a notch formed from the center of the tip thereof to the proximal end of the needle hole 121B, and one guide roller 732B is disposed inside the notch.

One end of the center feed belt 711B is routed to the motor pulley 722B, and the other end is routed to the guide roller 732B inside the notch of the needle plate 12B. Further, the two guide rollers 732B in the middle function as tension rollers so that the central feeding belt 711B does not slacken.

The guide rollers 733B of the left feed belt 712B and the right feed belt 713B are provided at four corners of the guide frame 731B, and form a substantially rectangular feed belt path surrounding the front end portion of the sewing machine base 21. The guide roller 733B includes a structure functioning as a tension roller, and is disposed so that the left feed belt 712B and the right feed belt 713B are brought into pressure contact with the motor pulley 722B without being loosened.

Two guide grooves extending in the X-axis direction are formed on the upper surface of needle plate 12B on both sides in the Y-axis direction with needle hole 121B interposed therebetween. The feed belts 711B to 713B are guided by the guide rollers 733B so as to pass through the inner sides of the two guide grooves of the needle plate 12.

These guide grooves are formed in the X-axis direction on both sides in the Y-axis direction via the needle hole 121B, and the depth of the grooves is formed shallower than the thickness of each of the feed belts 712B, 713B so as to be in good contact with the workpiece C placed on the upper surface of the needle plate 12B from below.

The center feed belt 711B is configured to convey the workpiece C on the needle plate 12B from below in a state of coming into contact with the workpiece C on the needle plate 12B from below on the downstream side in the feeding direction of the needle hole 121B as the needle dropping position by the guide mechanism 73B and the needle plate 12B.

The left feed belt 712B and the right feed belt 713B are configured to convey the workpiece C on the needle plate 12B in a state where the workpiece C is in contact with the right and left sides of the needle hole 121B as the needle drop position from below in a range from an upstream side to a downstream side in the feeding direction with respect to the needle hole 121B.

The rotation of the lower feed motor 72B is also controlled by the control device 90. In this case, the lower feed motor 72B is controlled so that the feed speeds of the feed motor 52 of the upper feed belt mechanism 50 and the workpiece C are equal to each other as a principle.

However, in order to cope with the case where a speed difference occurs in the feed speed of the upper portion and the lower portion of the workpiece C, the adjustment control for increasing or decreasing the rotation speed of the lower feed motor 72B may be performed independently of the feed motor 52.

When the feeding speeds of the lower feed motors 72B are independently controlled, the feeding speed of the lower feed motor 72B, or a speed difference or a speed ratio with respect to the feeding speed of the upper feed belt mechanism 50 is input from the operation panel 91.

As shown in the case of the feed motor 52 of the upper feed belt mechanism 50, the lower feed motor 72B may be provided with an adjustment dial to which an increase or decrease in the feed speed is input by a rotation operation.

[ technical Effect of the second embodiment ]

Since the flat-seam sewing machine 10B is provided with the lower feed belt mechanism 70B, unlike the lower feed mechanism that performs conveyance by the feed teeth intermittently contacting the workpiece C, the workpiece can be conveyed by the feed belts 711B to 713B always contacting the workpiece C. Therefore, the sewing object C can be conveyed in a state of always contacting with the feed belt from the top and bottom, and the upper part and the lower part of the sewing object C are not easy to deviate, so that the sewing can be performed with high sewing quality.

Further, since the feed belts 711B, 712B, and 713B are conveyed in contact with the lower side of the workpiece C, unlike the case of feeding the workpiece C by the feed teeth, the occurrence of damage or indentation due to the feed teeth can be reduced even in the case of the workpiece C having a step or thickness.

The center feed belt 711B is arranged so that a position in contact with the workpiece C and a needle drop position (needle hole 121B) are aligned in the X-axis direction, and is arranged so as to contact the workpiece C on the downstream side (front side) in the feed direction with respect to the needle drop position.

Therefore, the delay in the conveyance of the workpiece C by the sewing needle 11 can be reduced, and the workpiece C can be conveyed in a good entirety.

Further, since the left feed belt 712B and the right feed belt 713B are disposed on both sides in the Y axis direction via the center feed belt 711B, the three feed belts 711B to 713B can perform further excellent conveyance with straightness.

In the case of the lower feed belt mechanism 70B, as in the case of the upper feed belt mechanism shown in fig. 9, two lower feed motors may be provided, one lower feed motor may feed the center feed belt 711B and the left feed belt 712B, the other lower feed motor may feed the right feed belt 713B, and the feed speeds of these lower feed belts may be controlled individually. Further, the center feed belt 711B and the right feed belt 713B may be fed by one lower feed motor, and the left feed belt 712B may be fed by another lower feed motor, and the feed speeds of these lower feed belts may be controlled independently.

Alternatively, three lower feed motors may be provided, and the lower feed belt feed speed may be controlled individually for the center feed belt 711B, the left feed belt 712B, and the right feed belt 713B.

[ others ]

In the above-described upper feed belt mechanisms 50 and 50A, the case where three feed belts are provided is exemplified, but two feed belts may be provided. In this case, the removed feeding belt is preferably the left feeding belt 512 or the right feeding belt 513.

As described above, even when the feed belts are configured as two belts, the difference in the feed amount between the upper side portion and the lower side portion of the workpiece C can be reduced by controlling the speed of the feed motor 52 independently of the sewing machine motor.

In the lower feed belt mechanism 70B, similarly, two feed belts (the center feed belt 711B and the left feed belt 712B, or the center feed belt 711B and the right feed belt 713B) may be provided.

Further, when the left feed belt 512 (or the left feed belt 712B) is removed, the sewn product C is easily guided to be bent to the right side, and when the right feed belt 513 (or the right feed belt 713B) is removed, the sewn product C is easily guided to be bent to the left side, and the formation of the curved stitch by the manual operation can be easily performed.

Claims (9)

1. A flat-seam sewing machine which forms a plurality of stitches along a feed direction of a material to be sewn by a plurality of sewing needles and performs flat sewing in which a decorative thread spanning between the plurality of stitches is sewn,

the flat-seam sewing machine is characterized in that,

the upper feeding mechanism comprises: a plurality of feeding belts which are contacted with the sewed object on the needle plate from the upper part and convey the sewed object to the feeding direction; and a feed motor serving as a drive source for feeding the plurality of feed belts,

the plurality of feed belts of the upper feed belt mechanism have: a central feeding belt which is contacted with the sewed object at the downstream side of the feeding direction relative to the needle position; and a lateral feeding belt which is contacted with the sewed object at the adjacent position of the central feeding belt,

the bottom of the center feed belt is disposed at a lower position than the bottom of the side feed belt.

2. Flat-seam sewing machine according to claim 1,

the central feeding belt is configured to be arranged along the feeding direction at a position contacting with a sewed object and the needle drop position, and is configured to contact with the sewed object at the downstream side of the feeding direction relative to the needle drop position.

3. Flat-seam sewing machine according to claim 1 or 2,

the two side feed belts are disposed on both sides of the center feed belt with the center feed belt interposed therebetween.

4. Flat-seam sewing machine according to claim 1 or 2,

having a control device for controlling the feed speed by the feed motor,

the control device is provided with an adjusting disc, and the adjusting disc performs setting input on the feeding speed of the feeding motor through rotation operation.

5. Flat-seam sewing machine according to claim 1 or 2,

the upper feed belt mechanism has two of the feed motors,

one of the side feed belts and the remaining other feed belts are driven by the two feed motors independently.

6. Flat-seam sewing machine according to claim 1 or 2,

the plurality of feeding belts are supported by a presser foot plate which can press the sewed object from the upper part in a conveying way,

the presser foot plate is supported so as to be able to move up and down an upstream end portion in the feeding direction with a downstream end portion in the feeding direction as a fulcrum, and an elastic force is applied to the upstream end portion in the feeding direction in a downward direction by an elastic member.

7. Flat-seam sewing machine according to claim 1 or 2,

the plurality of feed belts are arranged to be supported by a presser foot plate that presses the sewing object from above so as to be conveyable, and are inclined upward on a downstream side in the feed direction of the presser foot plate,

the flat-stitch sewing machine includes a convex member that protrudes downstream in the feeding direction with respect to the plurality of feeding belts on a downstream side in the feeding direction with respect to the presser foot plate.

8. Flat-seam sewing machine according to claim 7,

the lower end of the convex member is inclined upward on the downstream side in the feeding direction.

9. Flat-seam sewing machine according to claim 1 or 2,

having a lower feed belt mechanism having: a plurality of feeding belts which are contacted with the sewed object on the needle plate from the lower part and convey the sewed object to the feeding direction; and a feed motor serving as a drive source for feeding the plurality of feed belts,

the plurality of feed belts of the lower feed belt mechanism have: a central feeding belt which is contacted with the sewed object at the downstream side of the feeding direction relative to the needle position; and a side feeding belt which is contacted with the sewed object at the adjacent position of the central feeding belt.

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