KR20010107577A - Sewing machine - Google Patents

Abstract

A sewing machine including a book 8 driven up and down about a vertical axis has a bobbin case 19 including a fan cam 28. The sewing machine is equipped with a capsule fan 30 including a fan lever 29 and an operating lever 32 from the fan cam 28. The actuating lever 32 is in contact with the cam 39 of the capsule fan drive device 33, which has a plurality of cam surfaces which affect the movement of the capsule fan 30 and the bobbin case 19, which are smooth and low in noise. .

Description

Sewing Machine

The present invention relates to a sewing machine, and more specifically, an arm, a base plate, a needle for guiding a sewing thread that can be driven up and down on an arm, and fixed to a bottom plate to be driven in a first rotational direction around a vertical axis. A bobbin case, a capsule fan, which is fixed to rotate in a drum, accommodates a bobbin equipped with a fan cam having a fixing lever that prevents the bobbin case from rotating in the first rotation direction through a fixed cam fixed to the drum and the bottom plate. And a capsule fan drive device having a cam having a cam surface and driven in a second rotational direction opposite the first rotational direction about the axis and at half the rotational speed relative to the rotational speed of the drum.

This type of sewing machine disclosed in DE-AS 1 072 069 (corresponding to UP-PS 2,949,783) includes a capsule fan formed as a cam in direct contact with the fan cam of the bobbin case. The cam is driven through an axis that is directly driven from the north drive shaft through a reduction gear. This configuration is very refined but has the following fundamental disadvantages. Relative motion occurs between the rotating cam and the fan cam of the bobbin case, causing wear at the point contact between the cam and the fan cam of the bobbin case. This wear can create sharp edges, especially on the fan cam, which can damage the sewing thread passing between the cam and the fan cam. In this section, a large friction force is applied to the sewing thread to increase the tension of the thread, which may cause the needle to bend. The fan cam is designed so that the sewing thread can be guided to the fixed bobbin case so that the friction is as small as possible. Therefore, the cam can be in smooth contact with the fan cam. The already disclosed capsule pan does not work harmoniously and thus does not suppress the strong rotary impulse applied to the bobbin case. This causes an impact on the bobbin case when the fixing lever strikes the fixing cam of the needle plate. Therefore, a negative effect is applied to the sewing process as well as noise is generated.

Due to the shortcomings of the known embodiments as described above, in the field, a fan lever which is generally in contact with the fan cam of the bobbin case is used in a capsule fan driven by an eccentric gear and a four bar chain arranged at the rear end. Included. Due to such forced movement, the relative air movement of the bobbin case is generated, which causes noise and wear.

The present invention is to overcome the above-mentioned conventional problems, an object of the present invention is to manufacture a sewing machine that proceeds smoothly so that the movement of the bobbin case can be significantly reduced noise generation and wear.

This object is solved through the features of the first claim according to the invention. Through the measures according to the invention it is possible to suppress the relative movement between the fan cam and the fan lever of the bobbin case and to suppress the disadvantages, that is, wear as described above. By arranging the drive of the capsule fan at regular intervals from the fan cam, oil can be applied to the contact surface between the support surface of the actuating lever and the cam without the risk of leaking into the area or seal near the drum. Since the cam is installed outside the fan cam section of the bobbin case due to the narrow space, the cam of the capsule fan driving device can be largely formed so that each cam surface can have a very smooth transition part. Therefore, the movement from the first position to the second position or the reverse direction of the fan lever proceeds smoothly so that the fixed lever can be operated smoothly with respect to the fixed cam, thereby preventing vibration or impact of the bobbin case. Noise is reduced through the aforementioned measures. In addition, the negative effect of the vibration of the bobbin case on the sewing is suppressed.

Claims 2 and 3 describe definitive measures on how the drive of the capsule fan is realized. Claim 4 describes measures for smoothing the rotational movement of the fan lever and bobbin case.

In principle, the actuating lever can be guided along a curve machined into a groove, for example in a groove. However, the form of the embodiment according to the fifth and sixth claims, in which the contact between the operating lever and the cam surface is secured through the features according to the seventh claim, is more preferable.

The action according to claim 8 allows the position of the fan lever with respect to the actuating lever to be precisely adjusted to compensate for manufacturing tolerances. Claim 9 describes a simple structural form for this.

It is possible through the preferred embodiment of the ninth claim that the capsule fan drive device is arranged in a relatively spaced apart position from the fan cam, i. In addition, due to the relatively large transmission rate, the movement of the fan lever can proceed very smoothly, which serves to further enhance the above-mentioned desirable effect.

Embodiments of the present invention are described in detail through the following drawings.

1 is a side view of a two-thread stitch sewing machine.

2 is a front view of a drum of the sewing machine cut along arrow II of FIG.

3 is a plan view of a book containing a capsule pan cut along arrow III of FIG.

4 is a plan view of a cam of the capsule fan drive device as an enlarged view of FIGS.

Explanation of symbols on the main parts of the drawings

1.arm 3.base 6.needle

8. North 9. Vertical axis

10. Buk-gu Coaxial 19. Bobbin Case

20. Fixed lever 21. Fixed cam 28. Fan cam

29. Fan lever

30. Capsule fan 32. Operating lever 33. Capsule driving device

39. Cam

40. Support surface 46. First cam surface 47. Shaft

48. 2nd cam surface 49. 3rd cam surface 50. 4th cam surface

1 to 4, a sewing machine according to the present invention is shown.

The double core sewing machine shown in FIG. 1 generally includes an upper arm 1, a vertical stand 2, and a bottom plate 3 in the form of a lower housing. The arm 1 has an arm spindle 4 for driving the needle bar 5 up and down together with the needle 6. In addition to this, a thread lever 7 is driven.

The base plate 3 includes a vertical book 8, that is, a book which can be rotated around the vertical axis 9. The drum drive shaft 10, which supports the drum 8 and is driven around the shaft 9, is supported in a rotatable form in the bearing stand 11 arranged on the base plate. It is driven by the helical gear 13 to the transmission shaft 12. The transmission shaft 12 is again driven by a synchronous belt drive 14 of the arm spindles 4. The transmission ratio of the synchronous drive belt 14 is 1: 1. The helical gear 13 is determined so that a transmission ratio of 1: 2 can be realized. This means that the drum 8 rotates twice when the arm shaft 4 or the transmission shaft 12 makes one rotation.

At the upper end of the book 8, that is, the upper part of the bottom plate 3, a sewing plate 15 including a stitch hole 16 is fixed by a screw 17. The book 8 formed in the form of a port includes a book beak 18 that operates right next to the needle 6 inserted into the sewing hole 16 and functions to hold a thread inserted into the sewing hole. have. The book 8 includes a bobbin case 19 which can be freely rotated about the book 8 about an axis 9. Likewise, the bobbin case 19 which is open to the top has a fixing lever 20 protruding outward radially with respect to the shaft 9 and upwards with respect to the sewing plate 15, which fixing lever 20 is a sewing plate. It is fixed to the lower end of the 15 so as to be rotatable only between the retaining cam (21, 22).

As shown in detail in FIG. 2, a first side gap 23 is formed between the first fixing cam 21 and the fixing lever 20 and an upper gap between the fixing lever 20 and the needle plate 15. A second side gap 25 is formed between the fixed lever 20 and the second fixed cam 22. The gaps 23, 24, and 25 form a through channel when the fixed lever 20 is located at the center, as shown in FIG. 2.

The bobbin case 19 is equipped with a bobbin 26 for receiving a thread, not shown here, which is fixed to the bobbin case 19 via a removable lock lever 27. The bobbin case 19 has a fan cam 28 protruding radially outward with respect to the shaft 9 at its upper edge and adjacent to the fan lever 29. The fan cam cooperates with the arm of a capsule fan 30 consisting of two angle levers. The capsule fan 30 is supported in a rotatable form by a bearing journal 31 fixed to the bottom plate 3. The arm of the capsule pan 30, which functions as another actuating lever 32, is guided to the capsule pan driving device 33. The pre-stressed tension spring 34 is attached to the capsule fan 30 near the bearing journal 31, which encapsulates the force that lifts the fan lever 29 from the fan cam 28 of the bobbin case 19. To the fan 30. The tension spring 34 is fixed on the one hand to the capsule pan 30 in the boring 35, and on the other hand to the base plate 3 via the fixing pin 36. The fan lever 29 and the operation lever 32 are coupled to each other in an adjustable form through the screw coupling 37. The screw coupling 37 has a function of compensating manufacturing tolerance so that the positioning of the fan lever 29 with respect to the bobbin case 19 is possible. The transmission rate of the effective length b of the operating lever 32 relative to the effective length a of the fan lever 29 is 1: 3 in this section.

The capsule fan drive device 33 has a camshaft 38 supported through the base plate 3, which is in contact with the support surface 40 that is convexly curved at the glass end of the operating lever 32 of the capsule fan 30. Due to the influence of the force of the tension spring 34 as described above, the actuating lever 32 of the capsule pan 30 is supported at the cam 39 via its support surface 40. The small gearwheel 42 is arranged on the north drive device 10, and the large gearwheel 43 is driven by the spur gear 41 which is in contact with the camshaft 38. The camshaft 38 is driven. The rotation ratio of the spur gear 41 is 2: 1. That is, when the drum 8 rotates twice, the cam 39 rotates once. As in the drive of the cam shaft 38 of the north drive shaft 10, the rotational direction 44 of the drum 8 and the rotational direction 45 of the cam 39 are opposite to each other.

It can be clearly seen in FIG. 4 that the cam 39 has a partially cylindrical first cam surface 46 running concentrically about the axis 47 of the camshaft 38. The first cam surface 46 is connected with a second cam surface 48 that increases in radial distance with respect to the shaft 47. The second cam surface 48 is connected to a third cam surface 49 with a slight increase in radial spacing with respect to the shaft 47. The third cam surface 49 and the first cam surface 46 are connected to each other by a fourth cam surface 50 in which the radial gap with respect to the shaft 47 again decreases. All cam faces 46, 48, 49, 50 are connected to each other at their perimeter. In addition, it can be seen from FIG. 4 that the first cam surface 46 is formed at an angle range of about 220 ° to 240 °. The second cam surface 48 occupies an angle range of about 50 degrees, the third cam surface 49 occupies an angle range of about 10 degrees to 15 degrees, and the fourth cam surface 50 has an angle of about 35 degrees to 40 degrees. Occupies a range.

In general, when the drum 8 rotates in the rotational direction 44, the rotation moment is applied to the bobbin case 19 in the same direction as the rotational direction 44 due to the friction between the drum 8 and the bobbin case 19. The bobbin case 19 rotates with the load and at the same time the fan lever 29 rotates to allow the fixed lever 20 to rotate in the direction of the first fixed cam 21.

Operation of the sewing machine according to the present invention by the configuration as described above is as follows.

First, the operation lever 32 will be described from the position of the capsule fan drive device 33 in contact with the first cam surface 46 through its support surface 40. When the capsule fan 30 is in this position, the fan lever 29 is placed in the highest first position in the fan cam 28 due to the influence of the force of the tension spring 34.

When the operating lever 32 is placed on the first cam surface 46, the fixed lever 20 is in contact with the first fixed cam 21. That is, the first side gap 23 is closed and the second side gap 25 is increased as in FIG. 3, unlike the intermediate position of the fixed lever 20 according to FIG. 2. In this state, the actuating lever 32 rotates as much as possible on the first cam surface 46 such that the gap 51 between the fan cam 28 and the fan lever 29 is 1.0 to 1.5 mm. The fan lever 29 rotates to the maximum in this first position. The thread loop 53 formed by the sewing chamber 52 at this position of the drum 8 and the bobbin case 19 is received through the book peak 18. The bobbin thread 54 is guided to the sewing hole 16 through the locking lever 27. With the rotation of the drum 8, the camshaft 38 rotates in the rotational direction 45, where the rotational speed of the camshaft 38 is due to the rotational ratio of the spur gear 41. That's half the number.

When the drum 8 continues to rotate, the seal loop 53 is guided around the bobbin case 19, which is fixed in position in a well-known general manner. Second cam surface 48 in which the radial spacing increases on the shaft 47 before the seal loop 53 is fully extended through the drum 8, that is, before being guided around the fixed bobbin case 19. ) Is in contact with the support surface 40 of the operating lever (32). Therefore, the rotation of the capsule fan 30 corresponding to the rotational direction 44 occurs, and this rotational movement proceeds in a direction opposite to the stress already applied to the tension spring 34. Since the second cam surface 48 is formed over a relatively large circumferential section of the cam 39, the rotational movement of the capsule fan 30 proceeds at a very low rotational speed. At this time, the fan lever 29 is idling first and the gap 51 between the fan lever 29 and the fan cam 28 disappears completely when the idling ends. At this time, the fan lever 29 contacts the fan cam 28 relatively smoothly. In the next process, the bobbin case 19 rotates very smoothly and continuously in the reverse direction of the rotational direction 44, that is, in a direction away from the first fixed cam 21. When the support surface 40 reaches the transition portion between the second cam surface 48 and the third cam surface 49, the fixed lever 20 is positioned between the two fixed cams 21 and 22 to provide an air gap 23, 24, 25 form a through channel. At this time, the fan lever 29 is placed at the second peak position opposite to the first position. That is, the fan lever 29 is placed at the maximum rotated position in the rotation direction 44. The channel is maintained until the support surface 40 is in contact with the third cam surface 49. As a result, the capsule fan 30 implements the first part of its working process. The seal 53 may be guided without any resistance to the channel formed through the air gaps 23, 24, 25.

As the book 8 continues to rotate, the seal 53 is opened. At this point, the fourth cam surface 50 is in contact with the support surface 40, which causes the capsule fan 30 to move at the second position of the fan lever 29 in the direction corresponding to the rotational direction 45. ) And the fan cam 28 is rotated to the first position where the gap 51 is formed. At this time, the fixed lever 20 is in contact with the fan cam 28. The fourth cam face is designed such that the rotational speed of the bobbin case 19 can be significantly reduced at the point where the fixed lever 20 meets the fixed cam 21. The seal loop 53 opened in the drum 8 passes through the gap 51 between the fan lever 29 and the fan cam 28 without any resistance, and bobbin thread 54 and two-strand sewing (two). -thread stitch).

Due to the shape of the cam 30 and the convex shape of the support surface 40 as described above, the operation of the fan lever 29 and the operation lever 31 with less noise and thus less wear are possible. In addition, the vibration of the bobbin case 19 is prevented even during a violent operation to prevent adverse effects on sewing.

As described above, the sewing machine according to the present invention can operate the fan lever and the operation lever with less noise and therefore less wear due to the convex shape of the cam and the support surface. In addition, there is an effect of preventing the bad influence on the sewing by preventing the vibration of the bobbin case even during intense operation.

In addition, by arranging the drive of the capsule fan at regular intervals from the fan cam, oil can be applied to the contact surface between the support surface of the operating lever and the cam without the risk of leaking into the area near the drum or the seal. Since the cam of the bobbin case is installed outside of the fan cam section, the cam of the capsule fan drive device can be largely formed so that each cam surface can have a very smooth transition, so that the cam lever can be moved from the first position to the second position of the fan lever. Movement in the reverse direction or the reverse direction is so smooth that the fixing lever can be operated smoothly with respect to the fixed cam has the effect that the vibration or impact of the bobbin case is prevented and the noise is reduced.

Claims (10)

An arm 1; A base plate 3; A needle 6 for guiding the needle thread which can be driven up and down on the arm 1 and A drum 8 fixed to the base plate 3 and driven in one rotational direction 44 around the vertical axis 9; A bobbin case 19 fixed for rotation in the book 8; The bobbin case accommodates a bobbin 26, The bobbin case has a fan cam 28; The bobbin case has a fixing lever 20 for preventing the bobbin case 19 from rotating in the rotational direction 44 through a fixing cam 21 fixed to the bottom plate 3. A capsule pan 30 formed in the form of an angle lever; The capsule fan has a fan lever 29 which can be contacted against the fan cam 28. Has an actuating lever (32), The capsule pan is rotatably supported; A capsule fan drive device 33; The capsule fan drive device has a cam (39) The capsule fan drive unit is rotated about half the rotation speed of the drum 8 around the shaft 47. The capsule fan drive device has cam faces 46, 48, 49, and 50 interlocked with the actuating lever 32. The first cam surface 46, which is partially cylindrical, has a narrow gap with respect to the axis 47, and likewise the third cam surface 49, which is partially cylindrical, has a wider space, The first cam face 46 and the third cam face 49 are then through the second cam face 48 with increasing spacing relative to the axis 47 and the third cam face 49 and the first cam face. 46 are continuously coupled to each other via a fourth cam surface 50 with decreasing spacing relative to the axis 47, At this time, when the first cam surface 46 and the operating lever 32 are interlocked, the fan lever 29 is placed in a first position spaced apart from the fan cam 28 and the fixed lever 20 is fixed cam 21. ), At this time, when the third cam surface 49 and the operating lever 32 is interlocked, the fan lever 29 is placed in a position close to the fan cam 28, and the fixed lever 20 is far from the fixed cam 21. Sewing machine, characterized in that configured to lose. 2. The sewing machine according to claim 1, wherein the fan lever (29) moves from the first position to the second position when the operating lever (32) cooperates with the second and third cam surfaces (48, 49). 3. The fan lever 29 according to any one of claims 1 and 2, wherein the fan lever 29 moves from the second position to the first position when the operating lever 32 is interlocked with the fourth cam surface 50. Sewing machine. A sewing machine as claimed in any one of claims 1 to 3, wherein the cam faces (46, 48, 49, 50) are connected to each other. The sewing machine according to any one of claims 1 to 4, wherein the actuating lever (32) is in contact with the cam (39) through a support surface (40). The sewing machine according to claim 5, wherein the support surface (40) is convex. 7. The capsule fan (30) is loaded by means of a tension spring (34) which presses in the direction of the first position of the fan lever (29) and from the cam (39) toward the support surface (40). Sewing machine, characterized in that. The sewing machine according to any one of claims 1 to 7, wherein the fan lever (29) and the operation lever (32) are coupled to each other in an adjustable form. The sewing machine according to claim 8, wherein the fan lever (29) and the operating lever (32) are coupled to each other through a screw coupling (37). 10. The fan lever 29 according to any one of claims 1 to 9, characterized in that the fan lever 29 has an effective length a and the actuating lever 32 has an effective length b and a ratio of a and b is 1: 3. Sewing machine.