JPH11216282A - Sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely capture a sewing thread with a looper and to form an appropriate stitch at the time of transferring an object to be sewn in an optional direction with respect to a ring sewing machine. SOLUTION: This sewing machine is composed of a needle bar 8 provided with a sewing needle 26 on a lower end and the looper supported by a supporting body provided on the lower part of a throat plate 30. In this case, the needle bar 8 is supported freely rotatably around the axial center, the throat plate 30 is attached to the supporting body for supporting the looper and the supporting body is constituted freely rotatably around the axial center of the needle bar 8. The rotating direction of the needle bar 8 and the supporting body is controlled corresponding to a stitch direction and the sewing needle 26 and the looper are turned to prescribed correspondence relation at least at the time of capturing the thread by the looper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine capable of controlling a rotation direction of a needle bar and a looper.

[0002]

2. Description of the Related Art A needle bar reciprocatingly driven up and down above a sewing object and a looper driven below the sewing object in full rotation synchronously with the needle bar cooperate with each other. A chain stitch sewing machine which performs the sewing of the above is widely put into practical use. In this chain stitch sewing machine, by lowering a needle bar provided with a sewing needle through which a sewing thread is passed at the lower end, the sewing needle pierces the workpiece, and at the timing when the stroke slightly exceeds the bottom dead center, the sewing thread Captured by the looper. This thread catching operation is performed for each reciprocating movement of the needle bar. Each time the thread catching operation is performed, the sewing object is moved by one stitch to form a so-called loop stitch. The sewing by the formation of the loop stitch does not require the supply of the lower thread, unlike the sewing of the lockstitch type requiring the upper thread and the lower thread because only one thread is used for sewing. There is an advantageous feature that the sewing machine can be continuously operated without interrupting the operation.

[0003]

By the way, in the above-described chain stitch sewing machine, it is possible to perform pattern sewing on the sewing object by moving the sewing object in the X direction and the Y direction in the plane coordinates like an embroidery sewing machine. Conceivable. If such pattern sewing is possible, a long string-shaped member such as a string-shaped decorative material or a heater wire can be continuously sewn to the sewing object, so that the sewing efficiency can be improved. However, in order to capture the sewing thread passed through the sewing needle with the looper, it is necessary that a predetermined relationship is established between the direction in which the sewing material is transferred for each stitch and the rotation direction of the looper. If this relationship is not satisfied, the sewing thread will not be captured by the looper and stitch formation will not be possible. Regarding the thread catching operation by the looper, the chain stitch sewing machine has a problem in performing the pattern stitching because the transfer direction of the workpiece is limited.

[0004] In this regard, a general sewing machine is configured to transfer the work to be sewn in only one direction. However, depending on the model, the work to be sewn is reciprocated like a sewing machine dedicated to attaching buttons. There are also things that do. In this type of sewing machine, the relationship between the rotation direction of the looper and the transfer direction of the sewing material is reversed for each stitch, and thus, a separately provided thread cutting device is controlled for each stitch, thereby enabling thread capture. In this case, the movement of simply reversing the transport direction of the sewn object by 180 ° is repeated, so that it is possible to perform the yarn catching by the yarn cutting device. However, in the case of arbitrarily controlling the transfer of the sewn object in the X and Y directions of the plane coordinates, it is practically impossible to realize this thread cutting device. In other words, this is not impossible at all in terms of structure, but the seams after sewing are not aligned neatly, so that the value as a product is reduced.

[0005]

SUMMARY OF THE INVENTION The present invention resides in a chain stitch sewing machine that performs sewing in cooperation with a needle bar that is reciprocated up and down and a looper that is fully rotated in synchronization with the needle bar. The present invention has been proposed to solve the above-mentioned drawbacks, and provides a configuration in which a sewing thread can be reliably captured by a looper to form a proper stitch even when an object to be sewn is transferred in an arbitrary direction. The purpose is to:

[0006]

SUMMARY OF THE INVENTION In order to overcome the above-mentioned problems and appropriately achieve the intended purpose, the present invention provides a needle bar having a sewing needle at a lower end thereof and a support provided below a needle plate. And a looper supported by the needle bar, the needle bar is rotatably supported around its axis, and the needle plate is attached to a support that supports the looper. The sewing needle and the looper are configured to be rotatable about an axis, and the rotation direction of the needle bar and the support body can be controlled in accordance with the stitch direction. It is characterized by having comprised so that it might become.

[0007]

Since the direction of the support of the needle bar and the looper can be controlled in accordance with the direction of transport of the sewing object, it is also possible to carry out pattern stitching in which the sewing object must be transported in any direction. In addition, the sewing operation of the sewing thread by the looper is always performed reliably, so that a beautiful stitch without skipping can be formed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of a sewing machine according to the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a vertical section of a sewing machine arm in the sewing machine according to the first embodiment, and FIG. 2 shows a vertical section of a looper device. In FIG. 1, a sewing machine arm 1 is fixed to a front surface of a frame 3 laid over a sewing machine table 2. A support portion 5 is protruded from a front portion of the sewing machine arm 1.
A rotating cylinder 7 is vertically and rotatably supported by the support portion 5 via a bearing 6. A hollow needle bar 8 is inserted into the rotary cylinder 7, is fitted approximately tightly on the inner circumference of the lower diameter-reduced portion of the rotary cylinder 7, and is supported so as to be vertically movable and rotatable about an axis. I have. A drive cylinder 10 is fitted on the outer periphery of the upper end of the needle bar 8, and a key 11 fixed vertically on the outer periphery of the lower end of the drive cylinder 10 is provided with a vertical keyway penetrating the peripheral wall of the rotary cylinder 7. 12. Therefore, the needle bar 8 can move up and down with respect to the rotary cylinder 7 and can rotate integrally with the rotary cylinder 7.

An annular groove 13 is provided around the outer periphery of the upper end of the drive cylinder 10, and a driver 14 is disposed at a side position of the drive cylinder 10. A fork-shaped forked portion 15 is fitted into the annular groove 13 at the upper end of the driver 14. A guide bar is provided beside the needle bar 8.
A needle (not shown) is erected in parallel with the needle bar 8, and a drive lever 17 is supported on the sewing machine arm 2 via a shaft 16 so as to be swingable. The driver 14 is supported by the guide bar so as to be movable up and down.
The lower end of 4 is connected to the free end of the drive lever 17 via a connecting lever 18 which is an intermediate connecting member. A sewing machine main shaft 20 that is located above the drive lever 17 and intersects with the arm 2 is disposed on the sewing machine arm 2, and an eccentric wheel 21 is fixed on the shaft of the sewing machine main shaft 20. A ring portion 22a is rotatably fitted on the outer periphery of the eccentric wheel 21, and a connecting rod 22 is attached to the ring portion 22a.
Is fixed, and the other end of the connecting rod 22 is connected to an intermediate portion of the drive lever 17.

The main shaft 20 of the sewing machine is connected to a motor (not shown), and is rotated in one direction by driving the motor. The rotation of the sewing machine main shaft 20 is converted into a vertical swing of the drive lever 17 via the eccentric wheel 21 and the connecting rod 22, and the swing of the drive lever 17 is controlled by the connecting lever 18 and the driver 14. The needle bar 8
Is converted to vertical reciprocation. A driven gear 23 is fitted to the lower end of the rotary cylinder 7, and the driven gear 23 meshes with a driving gear 24 disposed on the side thereof. The drive gear 24 is provided with a motor 2 provided inside the sewing machine arm 2.
5 is fitted to the output shaft. Accordingly, when the motor 25 is driven, the rotary cylinder 7 is rotated in one direction via the driving gear 24 and the driven gear 23. With the rotation of the rotary cylinder 7, the drive cylinder 10 engaged with the rotary cylinder 7 by the key 11 also rotates, whereby the needle bar 8 is also integrally rotated. A sewing needle 26 is attached to a lower end of the needle bar 8, and a sewing thread a inserted from an upper end opening 8a of the needle bar 8 is provided.
This extends outside from an opening 8b opened near the lower end of the needle bar 8, and is passed through a thread hole 27 of the sewing needle 26 (see FIG. 3).

A sewing needle 2 is provided below the sewing machine arm 2.
A needle plate 30 provided with a needle hole 31 that allows penetration of the needle plate 6 is provided, and a looper device is provided below the needle plate 30. That is, in FIG. 2, the support cylinder 32 is located below the needle plate 30 and on a downward extension of the vertical path of the needle bar 8.
The support cylinder 32 is rotatably supported by a support member 34 fixed to a sewing machine frame 33 via upper and lower bearings 35, 35. A drive shaft 36 is fitted inside the support cylinder 32 so as to be relatively rotatable, and the lower end of the drive shaft 36 is connected to an output shaft 38 of a motor 37 fixed to the frame 33 via a bracket 39. .

At the upper end of the support tube 32, a rotating bracket 40 functioning as a support for a looper 44 described later is fixed. The rotating bracket 40 has a rising portion 40a as shown in FIG. 2, and a looper shaft 41 is horizontally supported above the rising portion 40a so as to be rotatable. The axis of the looper shaft 41 intersects with the axis of the support cylinder 32, and a portion of the looper shaft 41 protruding inside the rising portion 40a is a driven gear 4 made of a bevel gear.
3 is fixed. The shaft portion 45 of the looper 44 is inserted and fitted into a center hole 41a formed at the shaft end of the looper shaft 41. A drive gear 46 composed of a bevel gear is fitted to the upper end protruding portion of the drive shaft 36, and meshes with the driven gear 43. Accordingly, when the motor 37 is driven to rotate the drive shaft 36 in one direction, the looper 44 is rotated in one direction via the drive gear 46 and the driven gear 43. The looper 44 has a hook 44a for catching the sewing thread a (see also FIGS. 3 and 4), and the hook 44a is rotated in a forward direction.

In FIG. 2, a driven pulley 47 is fitted between upper and lower bearings 35, 35 of a drive shaft 36, and a drive pulley 48 fitted to an output shaft 52 of another motor 51 fixed to the support member 34. And the driven pulley 47
And a belt 50 is stretched between them. When the motor 51 is driven, the support cylinder 32 is rotated in one direction via the pulleys 48 and 47 and the belt 50. Accordingly, the rotating bracket 40 fixed to the upper end of the support cylinder 32 is rotated, and accordingly, the looper 44 revolves around the axis of the needle bar 8, that is, the sewing needle 26.

The needle plate 30 further includes a rotating bracket 40.
The needle hole 31 attached to the upper end 40b of the needle plate 30 and formed in the needle plate 30 is a long hole. As is clear from FIG. 4 in which the needle plate 30 is observed from above, the needle hole 31 intersects at right angles with the shaft portion 45 of the looper 44 and is set so that the left side of the sewing needle 26 opens widely. . When the looper 44 revolves by driving the motor 51, the needle plate 30 also rotates. Therefore, the correspondence between the needle hole 31 and the looper 44 is always maintained in the state shown in FIG. . The positional relationship between the sewing needle 26 and the looper 44 is, as shown in FIG.
5 are parallel to each other, and the hook portion 44a of the looper 44 is preferably set to have a corresponding positional relationship on the back side of the sewing needle 26 (hereinafter, referred to as a "predetermined corresponding relationship between the needle bar and the looper"). .

Next, the mechanism of sewing by the sewing machine according to the embodiment will be briefly described. FIG. 3 shows a time-dependent process in which sewing is performed on the workpiece b. According to this, after the sewing needle 26 reaches the bottom dead center by piercing the sewing object b by the lowering of the needle bar 8, the hook of the looper 44 is turned at a timing of turning up and rising again (FIG. 2). The portion 44a captures the thread a, and further rotation of the looper 44 forms a loop in the thread a. Then, after the sewing needle 26 rises together with the needle bar 8 and comes out above the sewing object b, the sewing object b is transferred by a transfer mechanism (not shown) and moves one stitch to the left in FIG.
After the sewing needle 26 reaches the top dead center, the sewing needle 26 turns down again and pierces the sewing object, and the sewing needle 26 falls into the loop portion of the sewing thread a formed earlier. Next, at the timing when the sewing needle 26 starts to rise, the sewing thread a is again
Is captured by the hook portion 44a of the
By the rotation of, the loop portion comes off from the looper 44 to form one stitch. Thereafter, by repeating this, a so-called chain stitch shown in FIG. 3 is performed. The looper 44 is provided with the motor 37.
, So that the needle bar 8 is controlled to make one revolution every one reciprocation, that is, every one revolution of the sewing machine spindle 20.

FIG. 5 shows an example of pattern stitching. FIG. 5 (a) is a plan view and FIG. 5 (b) is a back view. In order to perform such pattern sewing, in the present embodiment, the direction of the needle bar 8 and the looper 44 is controlled for each stitch. That is, as shown in FIG. 6, assuming that the immediately preceding needle drop point on the sewing needle 26 is p and the next needle drop point is q, after the needle removal from the sewing object b at the needle drop point p is completed, After or simultaneously with the start of the transfer of the sewing object b, the direction of the sewing needle 26 and the looper 44 is controlled by driving the motors 25 and 51.
That is, in FIG. 6, the direction control is performed so that the straight line connecting the points p and q and the longitudinal direction of the needle hole 31 in the needle plate 30 are parallel to each other. By controlling the direction so that the hole core is parallel to the shaft portion 45 of the looper 44, the two motors 2 are driven so that the above-mentioned "predetermined correspondence between the needle bar and the looper" is established.
5 and 51. However, since the driving gear 46 and the driven gear 43 for rotating the looper 44 are in a relation of a differential gear, it is necessary to correct the rotation control amount of the looper 44 when controlling the direction of the looper 44. Further, the correspondence between the needle bar 8 and the looper 44 does not always need to be maintained at the predetermined correspondence, and the correspondence is established only at least at the timing of catching the sewing thread a by the hook portion 44a of the looper 44. It may be.

In this embodiment, since the needle hole 31 of the needle plate 30 is elongated, the loop portion of the sewing thread a formed by the looper 44 is inclined in the horizontal direction as shown in FIG. There is an advantage that the certainty that the sewing needle 26 falls into the loop portion is improved. However, this is not an essential element, and may be a slightly larger circular needle hole centered on the sewing needle 26 instead.

Next, FIG. 7 shows a second embodiment of the present invention. Members having the same or similar functions as the members shown in the first embodiment are denoted by the same reference numerals. Description is omitted. The difference from the first embodiment is that the looper 44 used in the first embodiment is replaced by a full rotary hook 144 for lockstitching, and the needle hole 131 of the needle plate 130 has a length as in the first embodiment. It is not a hole but a regular circular hole.
30 is attached to the lower surface. Also in the sewing machine according to the second embodiment, by controlling the direction of the needle bar 8 and the rotary hook 144 in accordance with the traveling direction of the seam, the fear of forming a so-called hitch stitch can be avoided.
All stitches can be perfect stitches to form beautiful seams.

In this embodiment, a single-head sewing machine having a single sewing machine arm has been described as an example. However, the present invention can be applied to a multi-head sewing machine having a plurality of sewing machine arms. In that case, the needle bar 8 in each sewing machine arm is
Drive is performed by a common sewing machine main shaft 20 penetrating through each sewing machine arm. On the other hand, as for each looper driving device, the rotation drive and the revolution drive of the looper are driven by individually installed motors as in the above embodiment. You may make it. Further, a rotation drive shaft and a revolution drive shaft common to each looper drive device may be provided in parallel with the sewing machine main shaft 20 and driven by mechanical connection with these shafts.

[0020]

As described above, according to the sewing machine of the present invention, the sewing operation of the looper always catches the sewing thread even when performing the pattern stitching in which the workpiece needs to be transferred in an arbitrary direction. Since high-quality embroidery products can be formed reliably and stitches without skipping can be formed, a high-quality embroidery product can be obtained. In the case of a chain stitch sewing machine, only one thread is used for the sewing, and there is no need to temporarily stop the lower thread supply during sewing unlike the lock stitch sewing machine. Can be continuously sewn without interrupting pattern stitching.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a sewing machine arm in a sewing machine according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a looper device according to the first embodiment of the present invention.

FIG. 3 is a longitudinal sectional view for explaining a sewing operation by the sewing machine according to the first embodiment of the present invention.

FIG. 4 is a partially cutaway plan view illustrating a relationship between a needle plate and a looper in the sewing machine according to the first embodiment of the present invention.

5A and 5B are sewing examples using the sewing machine according to the first embodiment of the present invention, in which FIG. 5A is a plan view of the sewing example, and FIG. 5B is a rear view of the sewing example.

FIG. 6 is an explanatory diagram of direction control by the sewing machine according to the first embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of a looper device section in a sewing machine according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sewing machine arm 5 Support part 7 Rotating cylinder 8 Needle bar 10 Driving cylinder 11 Key 12 Key groove 13 Annular groove 14 Driver 15 Forked part 17 Drive lever (link lever) 18 Connecting lever (link lever) 20 Sewing machine main shaft 21 Eccentricity Wheel 26 sewing needle 30 needle plate 32 support tube 36 drive shaft 37 motor 40 rotating bracket (supporter of looper) 40a rising portion of support 40b upper end of support 41 looper shaft 43 driven gear 44 looper 46 drive gear

Claims (2)

[Claims] A needle bar (8) having a sewing needle (26) at a lower end thereof;
A sewing machine comprising a looper (44) supported by a support (40) provided below the needle plate (30), wherein the needle bar (8) is rotatably supported about its axis, The needle plate (30) is attached to a support (40) that supports the looper (44), and the support (40) is configured to be rotatable about the axis of the needle bar (8), and is arranged in the seam direction. Accordingly, the rotation direction of the needle bar (8) and the support (40) can be controlled so that the sewing needle (26) and the looper (4) can be controlled.
(4) a sewing machine characterized by having a predetermined correspondence at least when the looper (44) captures a thread. 2. The sewing machine according to claim 1, wherein the looper (44) is a full-rotation type shuttle for lockstitching.