JPH1099573A - Sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the suitable setting of the bottom dead center and stroke of a fabric presser in every a plurality of sewing stitches by enabling the setting of the position of the bottom dead center and/or stroke of the fabric pressing member which is freely hoisted and lowered by an electrically-driven actuator at every step in a plurality of sewing steps in advance. SOLUTION: A driving tube 5 is fitted into the lower end of a needle bar 3 so as to be relatively rotatable and movable up and down. The driving tube 5 is guided by a guiding tube 6 fixed on the lower end of the head 2 of a sewing machine, and a supporting leg 7 is fixed on the lower end of the driving tube 5. A fabric pressing member 8 is installed to the lower end of the supporting leg 7 and driven by a fabric driving mechanism which comprises a pulse motor 22 and linking member. To the pulse motor 22, an encoder 41 for detecting the position of its rotation is installed. By the operation of the pulse motor 22, the hoisting and lowering member is driven to be moved up and down via the linking member, the driving tube 5 is moved up and down with the fabric pressing member 8. At this time, its bottom dead center is selected in advance at every sewing step.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine provided with a presser foot driving mechanism capable of easily changing the position of the bottom dead center and the size of a stroke of the presser foot.

[0002]

2. Description of the Related Art Conventionally, a presser foot of a sewing machine is configured to be driven by a link mechanism or the like using a spindle motor for driving a needle bar as a drive source. However, in recent years, a sewing machine of a type in which a control motor such as a pulse motor or the like is provided independently of a motor for driving the sewing machine main shaft so as to be able to separate from the sewing machine main shaft and drive only the cloth presser has been put to practical use. . If the presser foot is independently driven by the control motor separately from the sewing machine spindle in this way, the lifting timing of the presser foot with respect to the vertical movement of the needle bar, the lifting stroke of the presser foot, and the like can be arbitrarily set. Therefore, it is possible to expect an improvement in the finish of the sewn product.

[0003]

However, depending on the type of sewing machine, a plurality of sewing steps are set in advance in a microcomputer built in the sewing machine control unit, and the plurality of sewing steps related to the setting are set in advance of the sewing operation. Some of them are automatically executed. In such a sewing machine, it may be convenient if the bottom dead center and the size of the stroke of the work clamp can be arbitrarily changed for each step. For example, when sewing an applique material on a base cloth, a sewing step of performing a predetermined decorative sewing on the base cloth,
A sewing step of sewing an applique material to the base cloth. In the step of sewing the applique material, it is preferable to set the bottom dead center position of the work clamp to be higher by the thickness of the applique material, and it may be preferable to change the stroke of the work clamp to further increase the stroke. . However, despite the demands described above, there has been no sewing machine that can set the bottom dead center and the stroke size of the work clamp at each sewing step.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks inherent in the sewing machine, the present invention has been proposed to appropriately solve the drawback. It is an object of the present invention to provide a sewing machine capable of changing the setting of the sewing machine.

[0005]

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 which can be moved up and down freely, and a support member having a cloth holding member at a lower end. And a presser foot driving mechanism for driving the presser foot up and down freely by an electric actuator. The sewing machine is configured so that the bottom dead center position and / or stroke of the presser foot member can be set in advance for each of the plurality of sewing steps. I do.

[0006]

[Function] The bottom dead center and the size of the stroke
Since each step can be set in advance, the bottom dead center and the stroke length of the presser foot are automatically changed each time each sewing step arrives in the sewing process.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a sewing machine according to the present invention will be described.
A multi-head embroidery sewing machine capable of sewing a string-shaped material will be described below as a preferred embodiment with reference to the accompanying drawings.
FIG. 1 shows a longitudinal section of one sewing head 2 fixed to the front surface of a horizontal support frame 1. A needle bar 3 is vertically disposed and supported inside the sewing machine head 2 so as to be movable up and down. A driving cylinder 5 is fitted to the lower end of the needle bar 3 so as to be able to rotate and move up and down. I have. This drive cylinder 5
Is guided by a guide tube 6 fixed to the lower end of the sewing machine head 2, and a support leg 7 is fixed to the lower end of the drive tube 5. At the lower end of the support leg 7, a cloth pressing member 8 as shown in FIG.

[0008] The cloth presser member 8 is provided with a through hole 8a for allowing the insertion of a sewing needle 10 attached to the lower end of the needle bar 3, and guides a cord-like material (not shown) on the outer surface thereof. A guide 8b is attached. As shown in FIG. 2, a rotary cylinder 11 is fitted around the guide cylinder 6 so as to be rotatable only, and a bobbin 12 on which a cord-like material is wound is provided on the outer peripheral surface of the lower end of the rotary cylinder 11. Is mounted on the bracket 13 for rotatably supporting the bracket 13. The string-shaped material wound around the bobbin 12 is passed through a guide 8b, and then is led out to a gap between the pressing portion 8c of the cloth pressing member 8 and the embroidered cloth. A pulley 11a is provided around the upper end of the rotary cylinder 11, and the rotary cylinder 11 is driven to rotate via a belt stretched between a pulley (not shown) of a drive motor and the pulley 11a. . When the rotary cylinder 11 is driven to rotate, the direction of the bobbin 12 attached to the rotary cylinder 11 is controlled around the needle bar 3, and at the same time, the key 19 fixed to the rotary cylinder 11 and the key of the support leg 7. By the engagement with the groove 7a, the direction of the cloth pressing member 8 is also controlled around the needle bar 7 together with the support leg 7.

The needle bar 3 is reciprocated up and down by an elevating member 15 which is driven up and down behind the needle bar 3. As shown in FIG. 1, the elevating member 15 is supported by a guide bar 16 provided at a position behind the needle bar 3 so as to be able to move up and down, and a rod 18 fitted to an eccentric wheel 17 fixed to the main shaft 14 of the sewing machine. Are linked to each other through a link mechanism 20. When the main shaft 14 of the sewing machine rotates in one direction, the elevating member 15 is reciprocated up and down via the series of eccentric wheels 17, the rod 18 and the link mechanism 20, and the needle bar 3 is driven up and down accordingly. Lock-stitch sewing is performed in cooperation with a well-known shuttle provided below the needle plate 29.

Next, the presser foot driving mechanism 2 for reciprocating the presser foot member 8 in synchronization with the vertical movement of the needle bar 3 in a predetermined manner.
1 will be described. The presser foot driving mechanism 21 is configured as shown in FIG.
As shown in FIG. 1, the pulse motor 22 is constituted by a pulse motor 22 as an electric actuator fixed to the left side surface of the sewing machine arm 2 and a link member described later. As shown in FIG. 2, a guide bar 23 is provided on the left side of the needle bar 3 in parallel with the needle bar 3 at a predetermined interval. A first elevating member 24 and a second elevating member 25 each having a U-shape are fitted to the guide rod 23 so as to be able to move up and down. The first elevating member 24 and the second elevating member 25 have fitting holes 24a, 25a formed in the upper and lower horizontal portions, respectively, which are slidably fitted in the guide rod 23, and Lifting member 2
The upper horizontal portion 5 is disposed between the upper and lower horizontal portions of the first elevating member 24.

A cylindrical stopper 26 is slidably fitted to the guide rod 23 between the lower horizontal portion of the first elevating member 24 and the upper horizontal portion of the second elevating member 25. ing. A compression coil spring 27 is elastically fitted between upper horizontal portions of the first elevating member 24 and the second elevating member 25. The stopper 26 is pressed between the lower horizontal portion of the first elevating member 24 and the upper horizontal portion of the second elevating member 25 by the elastic expanding force of the compression coil spring 27. The first elevating member 24 and the second elevating member 25 are integrated.

A connecting member 28 having an L-shaped cross section is attached to a vertical portion of the second elevating member 25 by a screw 30 so that the vertical position thereof can be finely adjusted. A bifurcated connecting portion 28a is formed at a free end of the connecting member 28, and is formed in an annular groove 31a of a ring 31 fitted to an upper end portion of the driving cylinder 5 fitted to the needle bar 3. The connecting portion 28a is fitted. Therefore, the drive cylinder 5 is driven to move up and down while being allowed to rotate.

As shown in FIG. 5, one end of a connecting lever 33 is connected to a vertical portion of the first elevating member 24 via a pin 32, and is vertically swung by a fixed shaft 34 provided on the sewing machine frame 2 side. The other end of the connection lever 33 is connected via a pin 36 to one end of a swing lever 35 that is supported as possible. A pin 38 is provided at the other end of the swing lever 35.
The other end of the connection lever 37 is connected via a pin 40 to a drive lever 39 fixed to the output shaft 22a of the pulse motor 22. An encoder 41 for detecting the rotational position of the output shaft 22a is attached to the pulse motor 22, and the pulse motor 22 performs closed control based on a signal output from the encoder 41.

In the presser foot driving mechanism 21 having the above-described structure, the pulse motor 22 is rotated to drive the drive lever 39.
Is reciprocatingly rotated, the first elevating member 24 and the second elevating member 25 are driven up and down along the guide rod 23 via the respective levers, and the linking member 28 and the ring fixed to the second elevating member 25 are connected. The drive cylinder 5 is driven to move up and down together with the presser foot member 8 by engagement with 31.

The solid line in FIG. 3 indicates a state in which the drive arm 38 is rotated most clockwise and abuts against the stopper 45, and the cloth holding member 8 is lowered together with the first elevating member 24 to the lowest position (bottom dead center). Is shown. In this state, as shown in FIG. 4, the lower surface of the cloth presser member 8 is set in advance so as to be located at a bottom dead center NL slightly away from the upper surface position T0 of the needle plate 29. In this state, a Z signal is output from the encoder 22, which is output when the output shaft 22a of the pulse motor 22 reaches a reference angular position. However, actually, the cloth pressing member 8 is set so as to reach the bottom dead center NL immediately before the drive arm 38 comes into contact with the stopper 45.

The imaginary line in FIG.
8 rotates most counterclockwise and contacts the stopper 46,
As shown by the imaginary line in FIG. 1, a state is shown in which the cloth pressing member 8 together with the first elevating member 24 has reached the evacuation position which is the uppermost position. The retracted position is, specifically, the needle plate 29
Is set to a height of 26 mm from the upper surface position T0 of the above. Also in this case, in practice, the drive arm 38 is
Immediately before abutting on the contact member, the cloth pressing member 8 reaches the retracted position. Then, when one sewing step is completed and the process proceeds to the next sewing step, the cloth pressing member 8 is raised to the retreat position.

In the sewing machine according to the present embodiment, various string-like materials can be sewn to the embroidered cloth by various sewing methods. For example, first, normal embroidery sewing is performed in a first step, a tape-shaped cord-like material is sewn on an embroidered cloth in a second step, and a thick cord-like material having a circular cross section is sewn in a third step. By presetting a series of sewing steps such as attaching, these steps can be executed continuously. Needless to say, in each step, various operations such as replacing the string-shaped material guide 8b as needed and attaching an attachment for stitch stitching, which is a kind of sewing method, are necessary. Can be preset prior to entering the sewing operation in order to carry out the sewing process. As one of the contents of the preset, the setting of the bottom dead center and the setting of the stroke size of the cloth presser member 8 can be performed for each sewing step. That is, the bottom dead center NL can be set up to a position 3 mm higher in 0.5 mm units based on this position in this embodiment.
The stroke here indicates the distance from the bottom dead center NL to the top dead center NH. In this embodiment, the stroke can be set from 1.0 mm to 8.0 mm in units of 1.0 mm. ing.

Therefore, as in the above-mentioned example, in the first step, only ordinary embroidery is performed, so that both the bottom dead center and the stroke of the cloth holding member 8 are set to small values, and in the next second step, the tape is set. In order to sew a string-shaped material, both the bottom dead center and the stroke are set to values larger than those in the first step. Both the dead center and the stroke can be set to values larger than those in the second step. This makes it possible to select an appropriate bottom dead center and stroke of the cloth presser member 8 according to the sewn contents.
When the cloth pressing member 8 crosses the already sewn string material as the sewing progresses, it is possible to avoid a problem that the cloth pressing member 8 catches the string material.

In this embodiment, as in the case where the cloth pressing member 8 steps on an unexpected foreign substance or the like during the sewing,
When the movement of the cloth pressing member 8 to the bottom dead center is prevented, the compression coil spring 27 fitted between the first lifting member 24 and the second lifting member 25 causes the second lifting member 2 to move.
Since the relative upward movement of 5 is allowed, breakage of the presser member 8 or the drive system is effectively prevented.

In the present embodiment, an embroidery sewing machine capable of sewing a string-shaped material has been described as an example. Further, in the present embodiment, both the bottom dead center and the stroke of the presser foot member 8 can be individually and independently set. However, only one of them may be set.

[0021]

As described above, according to the sewing machine according to the present invention, the lower dead point and the stroke of the work clamp are automatically changed every time each sewing step arrives in the sewing process. The motion of the work clamp member is automatically set appropriately in accordance with the work. Therefore, the original function of the cloth holding member is exhibited without any support, and sewing with good sewing can be efficiently performed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a sewing head.

FIG. 2 is a cross-sectional view showing a part of a cloth presser driving mechanism.

FIG. 3 is an explanatory diagram of an operation of a cloth presser driving mechanism.

FIG. 4 is an explanatory view of the operation of the cloth pressing member.

FIG. 5 is an exploded perspective view of the presser foot driving mechanism.

[Explanation of symbols]

 2 sewing machine frame 3 needle bar 7 support leg (support member) 8 cloth presser member 21 cloth presser drive mechanism 22 pulse motor (electric actuator) 22a output shaft 23 guide rod 24 first elevating member 33 connecting lever 35 swing lever 37 connecting lever 39 Drive lever 41 Encoder

Claims (4)

[Claims] A needle presser (3) which is driven up and down and a support member (7) provided with a presser member (8) at a lower end thereof are driven up and down by an electric actuator (22). Mechanism (2
1), and the presser foot driving mechanism (21) is
(8) is reciprocated with a predetermined synchronization with the raising and lowering movement of the needle bar (3), and a plurality of sewing steps are configured to be set in advance.The cloth presser member (8) A sewing machine characterized in that a bottom dead center position and / or a stroke can be set in advance for each of the plurality of sewing steps. 2. The sewing machine according to claim 1, wherein a pulse motor is used as the electric actuator (22). 3. The cloth presser driving mechanism (21) is provided with the needle bar.
A first elevating member (24) fitted to a guide rod (23) provided in parallel with (3) so as to be able to move up and down; and a first elevating member supported by a sewing machine frame (2) so as to be vertically swingable. (24) Connection lever
A swing lever (35) having one end connected thereto via (33), and fixed to an output shaft (22a) of the electric actuator (22);
The sewing machine according to claim 1, wherein the sewing machine basically comprises a drive lever (39) connected to the other end of the swing lever (35) via a connecting lever (37). 4. An output shaft of the pulse motor (22).
The sewing machine according to claim 2, further comprising an encoder (41) for detecting the rotational position of the pulse motor (22a), wherein the pulse motor (22) is subjected to closed control based on a signal output from the encoder (41).