JP2000042271A - Fabric pressing mechanism for sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the vertical movement of a fabric processer foot follow a sewing speed even when the sewing speed gets higher, and at the same time, make the height of a bottom dead center location of the fabric presser foot properly adjustable. SOLUTION: For this fabric pressing mechanism 2 for a sewing machine, equipped with a fabric pressing rod 22 which is vertically movably supported, and to the lower end of which, a fabric presser foot 9 is attached, and a vertical movement mechanism 30 which converts the rotating movement of a main spindle 12 into a vertical movement of the fabric holding rod 22, an adjusting mechanism 35 which adjusts the height of a bottom dead center location of the fabric presser foot 9 is provided on the vertical movement mechanism 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a presser foot mechanism having an adjusting mechanism for adjusting the height of the bottom dead center of the presser foot.

[0002]

2. Description of the Related Art A conventional sewing machine provided with a cloth presser of this type is disclosed in Japanese Patent Application Laid-Open No. 10-99573. As shown in FIG. 7, in the presser foot mechanism 51 of the sewing machine, a pulse motor 53 is provided independently of a motor for driving the main spindle of the sewing machine, so that only the presser foot 50 is driven separately from the main spindle of the sewing machine. It has become.

The structure of the presser mechanism 51 will be described in detail. The presser mechanism 51 is provided with an elevating member 55 which can be moved up and down along a guide rod 54 supported in parallel with the needle bar. 55 is provided with a presser foot 5 via a driving cylinder or the like.
0 is attached. One end of a connection lever 57 is connected to the lifting member 55 via a pin 56, and the connection lever 5
The other end of 7 is connected to one end of a swing lever 59 via a pin 58. The swing lever 59 is vertically swingably supported by a fixed shaft 52 provided on the sewing machine frame. The other end of the swing lever 59 is connected to a connection lever 61 via a pin 60. The other end of the connection lever 61 is connected via a pin 62 to a drive lever 63 fixed to an output shaft 53a of the pulse motor 53. The pulse motor 53 is provided with an encoder (not shown) for detecting the rotational position of the output shaft 53a.
Reference numeral 3 indicates that closed control based on a signal output from the encoder is performed.

In this cloth presser mechanism 51, as shown in FIG. 7A, when the pulse motor 53 is rotated clockwise in FIG. 7A, the lifting member 55 is moved through the levers 63, 61, 59 and 57. When the pulse motor 53 descends and the pulse motor 53 is rotated counterclockwise as shown in FIG. 7B, the elevating member 55 rises. The bottom dead center position of the presser foot 50 raised and lowered by the raising and lowering member 55 is determined by the rotation angle of the output shaft 53a when the pulse motor 53 is reversed from clockwise to counterclockwise (detected by the signal output from the encoder). ) Can be changed by adjusting.

[0005]

However, since the pulse motor 53 must be rotated back and forth, the followability of the presser foot 50 to the needle bar is particularly poor when the sewing speed is increased, and the timing of ascending and descending is shifted. However, there is a problem that the vehicle may go down beyond the set bottom dead center position.

[0006] Such a problem does not occur if the presser mechanism is driven by the spindle similarly to the needle bar. However, this type of presser mechanism has heretofore been known by changing the mounting position of the presser foot. The height of the bottom dead center position was adjusted. More specifically, with reference to [Embodiments of the invention] described later, the screw 23 is loosened, the mounting position of the presser foot 9 with respect to the presser foot bar 22 is changed, and then the screw 23 is retightened. . Generally, in a multi-needle sewing machine, a cloth foot is often provided for each needle. Therefore, particularly in a multi-head type multi-needle sewing machine, it takes a lot of time and effort to adjust (for example, having nine needles). If the sewing machine has 20 sewing heads, it is necessary to adjust 180 times.), Which was very troublesome.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to make it possible to follow the lifting and lowering of the presser foot even when the sewing speed is increased, and to adjust the height of the bottom dead center position of the presser foot appropriately. It is an object of the present invention to provide a presser mechanism for a sewing machine capable of performing the above-described operation.

[0008]

In order to achieve the above object, a presser foot mechanism of a sewing machine according to the present invention comprises a presser bar having a presser foot mounted at a lower end and supported at a lower position, and a rotary motion of a main shaft. And a lifting mechanism for converting the pressure into a lifting / lowering movement of the pressure foot, wherein the lifting mechanism is provided with an adjusting mechanism for adjusting the height of the bottom dead center position of the pressure foot. And As the cloth presser bar,
There is no particular limitation as long as it is formed in a rod shape, and examples include a solid rod, a hollow rod, and a long plate (which may be formed in a U-shaped cross section, an L-shaped cross section, or an arc-shaped cross section). it can.

The lifting mechanism includes a cloth presser cam that is driven to rotate by the main shaft, and a cloth presser driving lever that swings by the cloth presser cam to move the cloth presser up and down. A mode in which the relative position between the presser cam and the cloth presser driving lever is adjusted can be exemplified.

The range of adjustment of the height of the bottom dead center position is not particularly limited, but it is preferably about 0.1 to 7 mm in terms of the height of the lower surface of the presser foot with respect to the upper surface of the needle plate. Is preferred. At this time, although there is no particular limitation, the distance between the lower surface of the work clamp and the upper surface of the work cloth is about -0.5 to +1.0 mm (a negative value indicates that the lower surface of the work clamp is lower than the upper surface of the work cloth. It is preferable to set a certain state, that is, a state where the work clamp presses down the work cloth.).

[0011]

1 to 5 show a sewing machine provided with a cloth presser mechanism 2 according to a first embodiment. First, the entire sewing machine will be described.
As shown in FIG. 2, a support 4 having a U-shaped cross section is provided.
A movable block 5 is supported on the front end side of the support 4 so as to be slidable left and right. A needle 10 is fixed to the lower end of the movable block 5 and nine needle bars 6 urged upward by a spring 7 are supported so as to be able to move up and down, and a balance 8 corresponding to each of the needle bars 6 is moved up and down. It is supported swingably. A main shaft 12 is rotatably supported on a back wall of the support 4 via a bearing 11. Further, the support 4 has a needle bar driving mechanism 13 for selectively driving up and down one of the needle bars 6, a balance driving mechanism 14 for swinging the balance 8 corresponding to the selected needle bar 6, A cloth presser mechanism 2 for driving the cloth presser 9 up and down in synchronization with the elevation of the needle bar 6 is provided. A needle plate 15 having a needle hole 15a through which the needle 10 is inserted is attached to a bed (not shown) provided corresponding to the sewing machine head 1.

The needle bar drive mechanism 13 includes a vertically extending guide rod 16 supported by the support 4.
An elevating body 17 is supported so as to be able to move up and down. Lifting body 17
Is provided with an engaging element 17a which engages with the engaging portion 6a of the needle bar 6, and is capable of engaging with the engaging portion 6a of the needle bar 6 positioned in front of the movable block 5 by moving the movable block 5 right and left. I have. A balance cam 18 for driving the balance is fixed to the tip of the main shaft 12, and the elevating body 17 is connected to a crank 19 attached to the front surface of the balance cam 18. When the main shaft 12 is driven to rotate, the crank 19 and the elevating body 1
One of the needle bars 6 is selectively driven to move up and down via 7.

The balance drive mechanism 14 has a balance drive lever 20 whose center is supported by the support 4 so as to be swingable up and down. Rollers 20a and 20b are provided at both ends of the balance driving lever 20, respectively.
a is engaged with a cam groove 18 a provided on the circumferential surface of the balance cam 18, and the roller 20 b at the other end is engaged with a concave portion 8 a at the rear end of the balance 8. When the main shaft 12 is driven to rotate, the balance 8 swings up and down via the balance cam 18 and the balance drive lever 20.

The presser mechanism 2 includes a presser bar 22 supported on the lower wall of the support 4 via a guide tube 21 so as to be able to move up and down.
The presser foot 9 includes a presser foot 9 attached to the lower end of the presser foot bar 22 with a screw 23, and an elevating mechanism 30 that converts the rotational motion of the main shaft 12 into an elevating motion of the presser foot bar 22.

The lifting mechanism 30 includes a cloth presser cam 31 that is driven to rotate by the main shaft 12, a cloth presser driving lever 33 that swings by the cloth presser cam 31, and raises and lowers the cloth presser 9 through the cushion mechanism 27. An adjusting mechanism 35 for adjusting the height of the lower dead center position of the presser 9 is provided.

The cushion mechanism 27 is provided on the upper end side of the cloth presser bar 22, and is opened in the front-rear direction.
The rectangular frame 24 is slidably supported vertically by the presser bar 22 by inserting the upper end of the presser bar 22 into holes provided in the upper and lower frames of the rectangular frame 24. ing. The rectangular frame 24 has a range of vertical sliding between the upper frame and the lower frame, which is fixed by the stopper 25 fixed to the presser bar 22, and is prevented from coming off from the presser bar 22. I have. A compression coil spring 26 is provided between the lower surface of the upper frame of the rectangular frame 24 and the upper surface of the stopper.
Is elastically fitted, and an O (O) ring 44 for buffering is interposed between the lower surface of the stopper and the upper surface of the lower frame of the rectangular frame 24. Even when the thickness of the work cloth is different depending on the embroidery place such as an applique, for example, the cushion mechanism 27 can be used in a portion where the work cloth is thick.
Is temporarily raised to absorb the difference in thickness.

The rectangular frame 24 of the cushion mechanism 27 is rotatably connected to one end of a short connecting arm 34 via a pin 28, and the other end of the connecting arm 34 is a cloth holder formed in an inverted letter shape. The drive lever 33 is rotatably connected to one end by a pin 29. The presser foot drive lever 33 is supported at its bent portion on the side wall of the support 4 so as to be swingable by a shaft 43. The presser foot driving lever 33 includes a roller 33a rotatably supported at the other end thereof.
The presser foot cam 31 is fitted in the presser foot cam groove 31a.

The presser foot cam 31 has a presser foot cam groove 31a for driving the presser foot and a position adjusting groove 31b used by an adjusting mechanism 35 described later on the circumferential surface thereof.
The bearing 11 is rotatably and slidably supported by a guide cylinder 11a protruding forward of the bearing 11. Guide tube 1
The reference numeral 1a extends to a position where it enters a concave portion 18c formed on the rear surface of the balance cam 18. A plurality of connecting pins 32 project from the front end face of the cloth holding cam 31, and the front end side of each of the connecting pins 32 is provided on the rear end face of the balance cam 18 corresponding to each of the connecting pins 32. It is slidably inserted into the hole 18b.

The adjusting mechanism 35 is supported by a base 37 fixed to the right side wall of the support 4 in FIG. 1 with a screw 36, and is rotatably supported by the base 37 in parallel with the longitudinal direction of the main shaft 12. A rotating shaft 40 a is connected to the male screw shaft 38 via a coupling 39 and the male screw shaft 38.
Stepping motor (with a speed reducer) 40 for rotating the shaft in a direction switchable manner, a female screw member 41 screwed to the male screw shaft 38 and linearly reciprocating with the rotation, and rotatably mounted on the female screw member 41. And a roller 42 which is provided and engages with the position adjusting groove 31b of the cloth presser cam 31.

The adjusting mechanism 35 moves the female screw member 41 forward or backward in accordance with the rotation direction of the stepping motor 40, and adjusts the position of the cloth pressing cam 31 via a roller 42 provided on the female screw member 41. It is designed to be moved forward or backward. When the position of the presser foot cam 31 is moved forward or backward, the presser foot cam groove 31 of the presser foot cam 31 is moved.
The rotation range of the presser foot drive lever 33 in which the roller 33a is fitted to and swings from a is shifted, and accordingly, the lifting range of the presser foot bar 22 and the presser foot 9 and the bottom dead center position are lowered or raised. Will shift. As described above, the adjusting mechanism 35 adjusts the relative position between the presser foot cam 31 and the presser foot drive lever 33, and thereby adjusts the height of the bottom dead center position of the presser foot 9.

The operation of the cloth presser mechanism 2 thus configured will be described. First, when sewing a thin work cloth W, the cloth holding cam 31 is positioned on the balance cam 18 side by the adjusting mechanism 35 as shown in FIG. 4A (the position is not limited to the position shown in FIG. 4A). It can be appropriately adjusted according to the thickness of the work cloth W.) Therefore, the presser foot cam 31
The swing range of the presser foot driving lever 33 which is swung by the movement of the presser foot 33 moves counterclockwise, whereby the lifting range of the presser foot bar 22 and the presser foot 9 moves downward. FIG. 5 is a solid line showing a state in which the presser foot 9 at this time is at the bottom dead center position.

When the main shaft 12 rotates, the main shaft 12
The balance cam 18 fixed to the tip of the shaft rotates. Then
The needle bar 6 and the needle 10 are moved up and down through the crank 19 and the elevating body 17 provided on the front end surface of the balance cam 18, and the balance 8 is swung up and down through the balance cam 18 and the balance drive lever 20. Be moved. At the same time, the presser foot cam 3
1 rotates, and the presser foot 2
2 and the presser foot 9 are moved up and down to a lower bottom dead center position corresponding to the thin work cloth W.

Next, when sewing a thick work cloth W or sewing a sewn object such as applique, see FIG.
As shown in (b), the presser foot cam 31 is provided with an adjusting mechanism 35.
(Not limited to the position shown in the figure, and can be appropriately adjusted according to the thickness of the work cloth W, etc.). For this reason, the swing range of the presser foot drive lever 33 moves clockwise, and accordingly, the lifting range of the presser foot bar 22 and the presser foot 9 moves upward. At this time, FIG.
As shown by a two-dot chain line, the bottom dead center position of the work clamp 9 has been moved higher than when the thin work cloth W is lowered.

The manner in which the position of the bottom dead center of the work clamp 9 is adjusted by the adjusting mechanism 35 is not particularly limited.
As disclosed by the present applicant in Japanese Patent Application Laid-Open No. 10-99572, the following embodiments can be exemplified. (1) A mode in which the position of the bottom dead center is adjusted to the height numerically input from the operation panel according to the thickness of the work cloth W.

(2) A mode in which the bottom dead center position is adjusted to a programmed height according to the thickness of the work cloth W at the embroidery location.

(3) A mode in which the position of the bottom dead center is adjusted according to the thickness of the work cloth W measured by the cloth thickness sensor.

The timing for adjusting the position of the bottom dead center of the work clamp 9 is not particularly limited, and may be a state in which the spindle is stopped or a state in which the spindle is rotating.

According to the sewing machine presser holding mechanism 2 configured as described above, since the lifting mechanism 30 for converting the rotational movement of the main shaft 12 into the lifting movement of the work holder rod 22 is provided, the sewing speed can be increased. The lifting and lowering mechanism 30 is provided with an adjusting mechanism 35 for adjusting the height of the bottom dead center position of the presser foot 9. The height of the can be adjusted.

Next, FIG. 6 shows a cloth presser mechanism 45 of a sewing machine according to a second embodiment. The cloth presser mechanism 45 is mounted on the male screw shaft 38 of the adjusting mechanism 46 instead of the stepping motor 40. Knob 4 for manually rotating screw shaft 38
7 is different from that of the first embodiment only in that it is attached.

According to the present embodiment, unlike the first embodiment, the height of the bottom dead center position of the work clamp 9 cannot be changed during sewing, but the actual operation is achieved by turning the knob 47 by hand. Since the height of the bottom dead center position of the work clamp 9 can be adjusted according to the work cloth W, the adjustment can be performed more easily.

The present invention is not limited to the configuration of the above-described embodiment, but can be embodied by appropriately changing it without departing from the gist of the invention, for example, as follows. (1) In a multi-head sewing machine, the sewing machine is configured so that the bottom dead center position of the work clamp can be adjusted simultaneously for all the sewing heads 1 or individually.

(2) The manner in which the rotational driving force of the main shaft 12 is transmitted to the presser foot cam 31 is changed. For example, in the above-described embodiment, the connecting pin 32 and the guide cylindrical portion 11a of the bearing 11 are omitted, a ridge or a concave groove extending in the length direction is provided on the surface of the main shaft 12, and the shaft hole of the cloth pressing cam 31 is formed. The presser foot cam 31 is inserted into the main shaft 12 so as to be slidable in the length direction of the main shaft 12 and non-rotatably in the circumferential direction.
Is transmitted to the presser foot cam 31.

(3) The adjustment mechanism is not limited to a specific structure, and the following mechanism can be exemplified. A spiral grooved cam provided on the outer periphery of the shaft, a motor for rotating the shaft so that the direction can be switched, a cam follower engaged with the grooved cam and linearly reciprocating with the rotation, and a presser foot for holding the cam follower And a roller fitted into the position adjusting groove 31b of the cam 31. A mechanism comprising a rack-and-pinion gear mechanism, a motor for rotating the pinion so that the direction can be switched, and a roller fitted into a position adjusting groove 31b of the cloth holding cam 31 in a part of the rack.

(4) The rotary shaft 40a of the stepping motor 40 or the male screw shaft 38 in the presser mechanism 2 of the sewing machine of the first embodiment is provided with a knob similar to that of the second embodiment, and the male screw shaft 38 is manually operated. To adjust the position of the bottom dead center of the presser foot 9 by rotating it.

[0035]

As described above in detail, according to the sewing machine foot press mechanism according to the first and second aspects of the present invention, even when the sewing speed is increased, the lifting and lowering of the work foot can be followed. The height of the bottom dead center position of the presser foot can be adjusted as appropriate.

[Brief description of the drawings]

FIG. 1 is a front view of a cloth presser mechanism of a sewing machine according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of the cloth presser mechanism.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a plan sectional view showing the operation of the cloth presser mechanism.

FIG. 5 is a side sectional view showing the operation of the cloth presser mechanism.

FIG. 6 is a plan sectional view of a presser foot mechanism of a sewing machine according to a second embodiment of the present invention;

FIG. 7 is a view showing the operation of a conventional cloth presser mechanism of the sewing machine.

[Explanation of symbols]

 2 cloth presser mechanism 6 needle bar 9 cloth presser 30 elevating mechanism 31 cloth presser cam 33 cloth presser driving lever 35 adjustment mechanism 45 cloth presser mechanism 46 adjustment mechanism

Claims (2)

[Claims] 1. A presser foot mechanism for a sewing machine, comprising: a presser foot bar which is supported so as to be able to move up and down and has a presser foot attached to a lower end thereof; , Wherein the lifting mechanism is provided with an adjusting mechanism for adjusting a height of a bottom dead center position of the presser foot. 2. The lifting mechanism includes a presser foot cam that is driven to rotate by the main shaft, and a presser foot driving lever that swings by the presser foot cam to raise and lower the presser foot. The presser foot mechanism of a sewing machine according to claim 1, wherein a relative position between the presser foot cam and the presser foot drive lever is adjusted.