TW201348550A - Sewing machine - Google Patents

Abstract

A sewing machine (1) has a frame (5a), a needle bar (9), which is driven to go up and down, with a sewing needle (10) and a looper (11). The latter is driven by a looper drive (14) to oscillate back and forth about a looper oscillating axis (12) of a looper oscillating shaft (13) and cooperates with the sewing needle (10) for stitch formation. The looper drive (14) has a drive unit (15) to produce a transmission oscillating movement about a transmission oscillating axis (17). Furthermore, the looper drive (14) has a traction drive (26) with a traction means (25) to convert the transmission oscillating movement (16) about the transmission oscillating axis (17) into a drive oscillating movement of the looper oscillating shaft (13). The result is a looper drive, in which a mechanical stressing of components is reduced.

Description

Sewing machine

The content of the German patent application DE 10 2012 206 208.4 is incorporated herein by reference.

The present invention relates to a sewing machine having a frame, a needle bar driven up and down, a needle, and a looper, wherein the looper is driven by the looper drive to wrap around the looper swing axis of the swing shaft of the looper Swinging and cooperating with the needle for forming a stitch, wherein the looper driver includes a drive unit to generate a drive swing motion about the drive swing axis, and includes a traction drive having a traction device for swinging the wraparound drive The drive oscillating motion of the axis is converted into a drive oscillating motion of the oscillating shaft of the circulator.

This type of sewing machine is known from public use. US 6,032,597 A shows a sewing machine having a needle bar, a looper and a looper drive. The looper swing axis extends perpendicular to the drive shaft. Furthermore, DE 25 53 363 A1 shows a sewing machine having means for generating a pivoting or pendulum movement on the output shaft by means of a drive shaft. The drive shaft is provided with two eccentric discs which are respectively looped by a flexible connecting member and convert the rotational motion of the drive shaft into a pivotal movement of the output shaft. The looper drive of the sewing machine is known to be subject to high levels of wear, especially when the sewing machine is used to sew very strong seams. In addition, the looper drive is very noisy.

It is an object of the present invention to develop a looper drive such that the mechanical stresses of the components of the looper drive are reduced.

This object is achieved according to the invention by a sewing machine having a looper drive, wherein the drive unit comprises a rotary drive shaft and a crank, one axial end of the crank having a drive connection connected to the drive shaft by means of an eccentric unit Wherein the eccentric unit is placed directly on the drive shaft, and the other shaft end of the crank has a transmission connection connected to the transmission wheel to pivot the transmission wheel back and forth (reciprocating, front and rear), the transmission wheel being pivotable The ground is mounted on the frame and mounted to pivot about the drive pivot axis.

It will be appreciated in accordance with the present invention that a looper drive of this type - also referred to as a swing or pendulum looper drive - reduces the reversal point region of the drive swing motion of the looper swing axis by using a traction drive Extreme load in the middle. On the one hand, this reduces the wear of the components of the looper drive. On the other hand, this also reduces the noise spread of the looper driver. Furthermore, the drive unit with the eccentric unit placed directly on the drive shaft is very robust. In addition, components can be saved and the construction cost of the sewing machine is reduced by this configuration of the drive unit.

In the drive unit, the traction device of the traction drive is guided on the outer circumference of the drive wheel. Such a drive unit is structurally simple and reliably converts the pivoting movement of the drive wheel into an oscillating movement of the oscillating shaft of the circulator.

In the drive unit, the drive shaft is also an arm shaft by means of which the needle bar is driven. Such a drive unit causes the drive motion of the looper to come from the rotational movement of the arm shaft. However, basically, the drive shaft of the looper drive is also It may be a shaft that is driven independently of the arm shaft. Finally, it is also possible to construct the sewing machine without the arm shaft.

The triangular eccentric unit reduces the mechanical stress of the crank. In addition, the angular velocity of the drive oscillating motion of the oscillating shaft of the circulator can be precisely matched to the movement of the needle bar, which increases the sewing reliability.

A traction device that uses a toothed belt (with a toothed belt) as the traction drive is very robust. The toothed belt can have a substantially elastic nature, which reduces the pulse transmission in the region of the reversal point that drives the oscillating motion, thus helping to reduce wear on the one hand and reducing noise on the other hand.

It has been proven in practice that the drive ratio of the traction drive is successful around 3:1. The angular amplitude of the transmission oscillating motion is converted to the angular extent of the drive oscillating motion that is increased via the gear ratio. The gear ratio can range from 2:1 to 4:1. The angular extent of the driving oscillating motion can be greater than 180°. The angular extent of the driving oscillating motion is preferably greater than 200°, greater than 220°, greater than 250°, and preferably about 270°. An angular extent of the drive oscillating motion of greater than 180° ensures that the upper wire is guided to knot near the looper casing of the sewing machine.

The sewing machine can have a looper swing axis that extends horizontally and parallel to the arm shaft, which allows the sewing machine according to the present invention to be used for needle transfer of the sewing material.

1‧‧‧ sewing machine

2‧‧‧ upper arm

3‧‧‧ column

4‧‧‧Substrate

5‧‧‧Bear axis

5a‧‧‧Frame

6‧‧‧ head

7‧‧‧High power motor

8‧‧‧Crank Drive

9‧‧‧ Needle bar

10‧‧‧ needle

11‧‧‧ barrel forming ring

12‧‧‧Activator swing axis

13‧‧‧Encoder swing axis

14, 37‧‧‧ Looper Driver

15‧‧‧Drive unit

16‧‧‧Drive oscillating motion

17‧‧‧Drive swing axis

18‧‧‧ crankshaft

19, 21‧‧‧ Axis

20, 38‧‧‧ eccentric unit

22‧‧‧Drive wheel

23‧‧‧Axial/radial bearings

23a‧‧‧bearing lining

24‧‧‧ outer weeks

25‧‧‧ traction device

26‧‧‧ traction drive

27‧‧‧ Drive oscillating motion

28‧‧‧The body of the looper

29‧‧‧ Tensioning roller; tensioning unit

30‧‧‧Up and down movement

32‧‧‧ Column side axial/radial bearing

33, 35‧‧‧Axial/radial bearings

36‧‧‧bearing lining

39‧‧‧Triangular eccentric body

40‧‧‧Four-sided eccentric receiver

III‧‧‧Observation direction

IV‧‧‧ viewing direction

V-V‧‧‧ hatching

VI‧‧‧Details

Embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings: Figure 1 shows in perspective a sewing machine for sewing a thick or strong sewing material as seen from the operator's side, wherein the internal details of the sewing machine mechanism are also partially shown; Figure 2 shows a looper drive of the barrel forming ring of the sewing machine according to Figure 1 in a perspective view corresponding to Figure 1; Figure 3 shows from the viewing direction III in Figure 2 - in other words in the lateral direction The plan view shows the looper drive; Figure 4 shows a view of the looper drive as seen from the viewing direction IV in Figure 3; Figure 5 shows the looper drive in the region of its traction drive A view along section line VV of FIG. 3; FIG. 6 shows detail VI of FIG. 4; and FIG. 7 shows a sewing machine of another configuration with a looper drive in a view similar to FIG.

detailed description

The sewing machine 1 has an upper arm 2, a vertical upright 3, and a lower casing generally referred to as a substrate 4. The sewing machine 1 is designed to sew a thick or strong sewing material such as a leather or plastic material board. The parts 2 to 4 shown in Fig. 1 show only their outlines.

In the arm 2, the arm shaft 5 is rotatably mounted on the frame 5a schematically shown in Fig. 1. One of the bearings of the arm shaft is disposed in the arm shaft end region on the column side, and the other of the arm shaft bearings is disposed in the opposite arm shaft end region in the head portion 6 of the sewing machine 1. The drive of the arm shaft 5 and the important sewing parts of the sewing machine 1 is carried out by means of the high-power motor 7 shown schematically in FIG. The needle bar 9 mounted vertically in the head 6 can be driven by the arm shaft 5 and the crank drive 8 to vertically move up and down, the needle bar carrying the organic needle 10 at its lower end.

Below the needle bar 9, the barrel forming ring 11 is driven to oscillate back and forth about the looper pivot axis 12 of the looper swinging shaft 13 in the base plate 4. The barrel forming ring 11 is also referred to as a barrel shuttle. The looper pivot axis 12 extends horizontally and parallel to the arm shaft 5. The barrel forming ring 11 cooperates with the needle 10 to form stitches and seams in the sewing material. Since the looper swing axis 12 is parallel to the arm shaft 5, the swinging motion of the tub forming ring 11 is parallel to the conveying direction of the sewing material. The conveying direction is perpendicular to the C-shape of the sewing machine 1 formed by the arm 2, the column 3 and the substrate 4. The progression of the looper axis 12 parallel to the arm shaft 5 allows the sewing machine 1 to be equipped with an organic needle transport mechanism because the needle can be moved in the sewing direction after insertion into the sewing machine during operation of the sewing machine 1, and the needle is not This will enter the movement path of the barrel forming ring 11 .

The oscillating drive of the tub forming ring 11 is performed by means of the looper driver 14. FIG. 2 shows the components of the looper drive 14. The looper drive 14 has a drive unit 15 for generating a drive swing motion (double arrow 16 in Fig. 2) about the drive swing axis 17 (see Fig. 1).

The drive rocking axis 17 extends parallel to the axes 5 and 13.

The arm shaft 5 serves as a rotary drive shaft of the drive unit 15. Furthermore, the drive unit 15 has a crank axle 18. The axial end of the crankshaft 18 is embodied as a pivot 19 having a drive connection to the drive shaft 5 by means of an eccentric unit 20 . In a preferred embodiment variant according to FIGS. 1 to 6, the eccentric unit 20 is placed directly on the drive shaft 5. The other axial end of the crankshaft 18 is also constructed as a shaft eye 21 and has a drive connection to the drive wheel 22 by means of an axial/radial bearing 23 (see Figs. 4 and 6). The drive wheel 22 is pivotally mounted about the drive rocking axis 17 on the bearing bushing 23a (see Figure 5).

The crankshaft 18 has a drive connection to the drive wheel 22 for pivoting back and forth about the drive rocking axis 17.

The traction device 25 of the traction drive 26 of the looper drive 14 is guided over the outer circumference 24 of the drive wheel 22. The transmission 25 is constructed as a toothed belt. The toothed belt meshes with the external tooth system of the outer circumference 24 of the drive wheel 22.

The traction drive 26 is used to convert the drive oscillating motion 16 of the drive wheel 22 about the drive pivot axis 17 into a drive oscillating motion of the circulator swing axis 13 (see double arrow 27 in Fig. 2).

Traction drive 26 has a gear ratio approaching 3:1. If the transmission wheel 22 performs a transmission oscillating movement of 90° peripheral amplitude about the transmission yaw axis 17, the circulator shaft 13 performs a oscillating motion of 270° around the circulator axis 12 due to the action of the traction drive 26, thereby Correspondingly, the looper body 28 of the tub forming ring 11 performs a pivotal movement of 270° amplitude about the looper pivot axis 12.

The traction device 25 of the traction drive 26 is constructed as a continuous toothed belt and is guided to the end of the cylinder on the column side of the ring swinging shaft 13 in connection with the drive. The traction device 25 is held in a tensioned state via a tensioning unit 29, which is configured as a tensioning roller rotatably mounted on the frame 5a (see Fig. 2).

During the operation of the sewing machine 1, the arm shaft 5 is driven to rotate by the high power motor 7. The rotation of the arm shaft causes an up and down movement by means of the eccentric unit 20 (see double arrow 30 of the crankshaft 18). This up and down movement 30 translates into a transmission oscillating motion 16 due to the drive connection of the axle eye 21 to the drive wheel 22. By means of the traction drive 26, the transmission oscillating movement about the drive pivot axis 17 is converted into a circulator The oscillating movement 27 of the oscillating shaft 13 is driven. For the formation of stitches and seams, the looper body 28 of the barrel forming ring 11 moves in synchronism with the needle 10 and grips the upper loop, which is guided by the needle 10 through the seam and then knotted Wherein the upper wire is guided and knotted during the 270° movement of the looper body 28 around the looper housing.

The looper drive 14 with the traction drive 26 avoids mechanically extreme loading in the region of the reversal point of the drive swing motion of the looper swing shaft 13.

Figure 5 shows in more detail the column-side axial/radial bearing 32 of the ring-forming pivot axis 13 on the frame 5a of the sewing machine 1, and the axial/radial bearing 33 of the drive wheel 22 about the drive rocking axis 17. . The bearing is located on a bearing bush 23a that is non-rotatably coupled to the frame 5a.

Figure 6 shows a further axial/radial bearing 35 for mounting the tensioning roller 29 on the bearing bushing 36, which is rigidly supported by the frame 5a.

FIG. 7 shows a further configuration of the looper driver 37 for the barrel forming ring 11. The components and functions that have been described above with reference to FIGS. 1 through 6 have the same reference numerals and will not be described again in detail. In contrast to the circular eccentric unit 20, the rotational movement of the arm shaft 5 is converted into the up and down motion 30 of the crank shaft 18 using a triangular eccentric unit 38. The arm shaft 5 is here non-rotatably connected to a triangular eccentric body which rotates in the four-sided eccentric receiver 40. The triangular eccentric body 39 has a casing wall in the form of a spherical triangle. Matching the outer casing wall is the inner casing wall of the four-sided eccentric receiver 40 in the form of a spherical square. The triangular eccentric unit 38 avoids applying extreme mechanical stress at the reversal point of the up and down movement of the crankshaft 18.

In an alternative embodiment of the looper driver 14 or 37, a pass can be used The traction drive is located in the range of 2:1 to 4:1.

1‧‧‧ sewing machine

2‧‧‧ upper arm

3‧‧‧ column

4‧‧‧Substrate

5‧‧‧Bear axis

5a‧‧‧Frame

6‧‧‧ head

7‧‧‧High power motor

8‧‧‧Crank Drive

9‧‧‧ Needle bar

10‧‧‧ needle

11‧‧‧ barrel forming ring

12‧‧‧Activator swing axis

13‧‧‧Encoder swing axis

14‧‧‧Encoder Drive

15‧‧‧Drive unit

17‧‧‧Drive swing axis

19‧‧‧Axis

25‧‧‧ traction device

26‧‧‧ traction drive

Claims (7)

A sewing machine comprising: a frame, a needle bar, the needle bar being driven to move up and down, and having an organic needle; a looper driven by the looper drive to wrap around the looper The looper swing axis oscillates back and forth and cooperates with the needle to form a stitch, wherein the looper drive comprises: a drive unit that produces a drive swing motion about the drive swing axis a traction drive having traction means for converting a drive oscillating motion about the drive pivot axis into a drive oscillating motion of the circulator shaft of the circulator, wherein the drive unit comprises: - a rotary drive shaft, a crankshaft, - one axial end of the crankshaft having a drive connection connected to the drive shaft by means of an eccentric unit, wherein the eccentric unit is placed directly on the drive shaft, the crankshaft The other shaft end has a drive connection to the drive wheel for pivoting the drive wheel back and forth, the drive wheel being pivotally mounted on the frame and mounted to be able to swing around the drive Pivot axis. A sewing machine according to the first aspect of the invention, characterized in that The traction device of the traction drive is guided on the outer circumference of the transmission wheel. The sewing machine according to claim 1, wherein the drive shaft is also an arm shaft by which the needle bar is driven. The sewing machine according to the first aspect of the invention, characterized in that the eccentric unit is configured as a triangular eccentric unit. A sewing machine according to the first aspect of the invention, characterized in that it comprises a toothed belt for use as a traction means for the traction drive. A sewing machine according to the first aspect of the invention, characterized in that the traction drive has a gear ratio of approximately 3:1. The sewing machine according to claim 1, wherein the looper swing axis extends horizontally and is parallel to the arm shaft.