CZ291426B6 - Sewing machine - Google Patents

Abstract

In the present invention there is disclosed a sewing machine comprising an upper part mechanism for feeding the material to be sewed and being formed by both a plunger (37) carrying a foot (36) and a lifting rod (51) that is rotatably coupled to an upper feeder (32) of the material to be sewed. A lifting drive (53) for the upper feeder (32) of the material to be sewed has a vibrating lifting shaft (73) and a lifting drive joint joining the lifting rod (51) with the vibrating lifting shaft (73). The lifting rod (51) sliding in linear direction and arranged next to the plunger (37) at a certain distance therefrom and parallel thereto forms a part of the lifting drive (5). The lifting rod (51) is loaded with a second spring in the direction to an aperture (25). The lifting drive joint is supported on the plunger (37) and when the lifting rod (51) is lifted against the direction of feed (48), it loads the lifting rod (37) in the direction toward the aperture (25) by the action of a second spring.

Description

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a sewing machine having an upper device for conveying sewn material.

BACKGROUND OF THE INVENTION

DE-GM 1 974 416 (corresponding to U.S. Pat. No. 3,614,934) discloses a sewing material feed device in a sewing machine, in which the sewing presser consists of a hollow push rod to which the foot is attached. The linearly displaceable push rod is loaded by a tension spring in the direction of the needle hole of the sewing machine. In the hollow push rod, a lifting rod for the upper feeder of sewn material, which is pivotally connected to the lifting rod, is slidably mounted. A crank lever is rotatably mounted on the push rod, one arm of which is rigidly connected to the lifting shaft by means of a crank drive, and the other arm of which is connected to the lifting rod. The lifting rod is loaded by an additional spring in the direction of the puncture opening. When the top sewing material feeder is lifted from the stitch hole to perform an empty stroke, during this time, when the needle is inserted into the sewing parts and the stitch is tightened, the presser foot will be pressed against the sewing part towards the sewing part a puncture hole. The arrangement of the lifting rod in the push rod leads to considerable friction in the upper device for conveying the sewn material, which adversely affects the high-speed drive of the sewing machine with a high number of stitches per minute.

It is known from DE 41 31 058 A1 to provide a crank lever for the foot of the upper device for conveying the workpiece to be sewn, one arm of which is pivoted by its pivot point at the pivot point. By shifting the cranked lever relative to the pivotable drive lever, the angle by which the cranked lever swings, changing the lift movement of the shoe.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a sewing machine with an upper device for conveying sewn material that can operate at high speed to produce a high number of stitches.

SUMMARY OF THE INVENTION

This task is accomplished by a sewing machine having an upper arm, a rotatably driven shaft arranged in the upper arm, a needle bar carrying the needle, driven by a shaft and sliding up and down in the upper arm, with a base plate with a puncture hole through a base plate under the needle, and an upper sewing material displacement device arranged in the upper arm, wherein the upper sewing material displacement device is provided with a thrust bar formed by a push rod sliding downwardly linearly in the feed direction and loaded by the first spring in the feed direction and a foot located on the push bar at the puncture hole, with a top feed unit of sewing material, with a lift drive for the top feed unit of sewing material, provided with a pivotally driven lift shaft and a lift drive coupling connecting the lift bar to the lift shaft; with a pusher drive for the sewing material upper feeder provided with a pendulum driven pusher shaft and a pusher drive coupling connecting the sewing material feeder to the pusher shaft according to the invention, wherein the lifting drive is further provided with a linearly displaceable lifting bar arranged adjacent a push rod spaced therebetween and parallel thereto, with which the top feed of the sewn material is pivotally connected, the lifting rod being loaded by a second spring in the direction of the puncture opening, and wherein the lifting drive connection is supported on the push rod and In the direction of the feed direction, the pressure bar loads the second spring in the direction of the puncture opening.

-1 CZ 291426 B6

By placing the push rod and the lifting rod completely independently of one another, it is achieved that during the working phase, i.e. the transport phase, of the top sewing material feeder, the top sewing material feeder does not exert any transverse or longitudinal force on the pressing bar of the pressing device sewing machine. The top sewing material feeder and the foot are arranged on the guide bars, i.e. on the lifting rod and the push rod, formed independently of each other.

According to a preferred embodiment, the second spring in the push rod acts on the bearing fixedly connected to the lift rod.

Preferably, the push rod is at least partially designed as a hollow rod, and wherein the second spring is formed by an inner spring that abuts the first end against a bearing arranged in the push rod.

The inner spring is preferably supported by the other end on the set screw.

Preferably, the lift drive linkage comprises a crank lever pivotally mounted about an axis on a push rod, with a first arm and a second arm, the first arm cooperating with a pivoted drive lever coupled to the lift shaft and its engagement point abutting the first arm, the engagement from the axis decreases when the push rod is lifted from the puncture opening, and whose second arm abuts the lift rod.

The lifting shaft and the sliding shaft are preferably arranged concentrically with each other.

Preferably, the first spring is formed by an outer spring which is supported on one side by a push rod and on the other side by an adjustable foam, adjustable relative to the upper arm.

BRIEF DESCRIPTION OF THE DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a sewing machine according to the present invention; FIG. 2 is a side elevation view of the sewing machine as seen in the direction of arrow II in FIG. FIG. 3 is an enlarged sectional view of the section of FIG. 2; FIG. 4 is a section along the line IV-IV of FIG. 2; FIG. 5 is an enlarged section of FIG. 1 and 7, FIG. 7 is a partial cross-sectional view of the sewing machine as seen in the direction of arrow VII in FIG. 2; FIG. 8 is a transverse cross-sectional view along the line VIII-VIII in FIG. 1 and 7 and 9 schematically show the kinematics of the drive train of FIG. 2.

-2GB 291426 B6

DETAILED DESCRIPTION OF THE INVENTION

The double-threaded sewing machine 1 is mounted on the table 2. The sewing machine 1 has an approximately vertically arranged stand 3, from which the upper casing-shaped upper arm 4 and the lower base plate 5 also in the form of a casing protrude in the horizontal direction. The sewing machine 1 has the usual C-shape. In the upper arm 4 a shaft 6 is mounted, at one end of which - outside the stand 3 - a handwheel 7 is mounted. The shaft 6 is driven by a controlled drive 8 located at the bottom of the table 2; this drive 8 consists essentially of a motor 9 with a coupling and brake unit and a control unit 10. The transmission of the driving torque from the motor 9 to the handwheel 7 is effected by means of a V-belt drive 11.

The needle bar 13 mounted in the front of the upper arm 4 is driven by the shaft 6 in a conventional manner by means of the crank drive 12 (FIG. 2). In the same way, the shaft 6 is driven at twice the frequency by the transmission. The position sensor 15, which transmits signals corresponding to the frequency of rotation of the shaft 6 and signals corresponding to the angular rotation of the shaft 6 via the transmission line 16 to the control unit 10, is non-rotatably connected to the shaft 6.

On the upper arm 4 there is arranged a bobbin 17 with a yarn supply from which the needle thread 18 is removed. This needle thread 18 is guided around the roller 19 to the tensioner 20 and thence by a lever 21. From this lever 21 the needle thread 18 is guided approximately vertically downwards a needle clamp 22 to the needle 23, which is located on the needle bar 13. The needle thread 18 extends through the eye 24 of the needle 23. The needle 23 extends up and down through the stitching hole 25 provided in the plate 26 arranged approximately in alignment with the upper side. The tip 27 of the hook 14 driven by the drive shaft 28 moves around the needle 23, respectively along its vertical path.

In the table 2 there is provided a lower sewing material feed device, of which only the lower sewing material feeder 29 is arranged, arranged on both sides of the plate 26, which is driven in a conventional manner and which serves to convey the lower sewing part 30 direction 31 sewing. In order to convey the lower part 30 in the sewing direction 31, the lower sewing material feeder 29 abuts the lower part 30. Then it performs a free movement downwards and against the sewing direction 31 and then rises again to the lower part 30. This embodiment is widely practiced.

In the upper arm 4 there is arranged an upper seam conveyor, functionally associated with the lower seam conveyor, and the upper seam conveyor will now be described in more detail. The top suture feed device comprises a fork-shaped top suture feeder 32 disposed above the bottom suture feeder 22, the top suture feeder 32 serving to convey the top suture 33 in the stitching direction 31. Both feeders 29 and 32 are provided with a toothing 34 facing the respective parts 30 and 33. Inside the upper feeder 32 of the stitched material in the shape of a fork is provided a foot 35 of the bead 36 which presses both parts 30, 33 in the region of the plate 26 when the needle is pressed. 23 is inserted into the parts 30, 33 until it is withdrawn again. The sewing technique described so far is generally conventional and known.

The foot 36 itself is mounted on a first bar serving as a push rod 37, which is slidably mounted in a first housing 38 arranged parallel to the needle bar 13 in the upper arm 4. This creates a thrust device 37a for pressing the sewn material. The push rod 37 is loaded by an external spring 39 formed as a coil spring, i.e. a first spring which is supported by an adjustable support 40 arranged in the upper part of the upper arm 4 and formed as a screw-in threaded sleeve. An external spring 39 biased by a pressure-adjustable bias is supported on the push rod 37 via a stop 41. The adjusting support 40 formed by the threaded sleeve passes through a set screw 42 which is adjustable by a thread 43 relative to the adjustable support 40 formed by the threaded sleeve. This set screw 42

Further, the rod part 44, the outer spring 39 and partly pass through the hollow push rod 37, as shown in particular in FIG. 3. In addition, the inner spring 45, the second spring, is arranged in the hollow push rod 37. This inner spring 45 rests on a shoulder on the rod portion 44 of the set screw 42, which serves as a support 46. At its other end, the internal spring 45, whose pressure bias is adjustable by the set screw 42, rests on the bearing 47, see FIG. against which the push rod 37 is movable. For this purpose, the push rod 37 is provided in this part with a longitudinal bore 49 extending in the feed direction 48 through which a bolt fixed in the bearing 47 serves as a stop for the inner spring 45. with respect to the push rod 37 and is loaded by the second spring, i.e. the inner spring 45, in the direction of the table 2, namely by a force adjustable by the adjusting screw 42.

The bearing 47 is mounted on a lifting rod 51, i.e. a second rod arranged parallel to the push rod 37, wherein the lifting rod 51 is also displaceably displaced in the feed direction 48 in the second housing 52. Also the second housing 52 is mounted in the upper arm 4, Thus, the inner spring 45 directly loads the lifting rod 51 in the feed direction 48.

The stitched material feeder 32 is driven by a lifting drive 53 for pushing the stitched material feeder 32 towards and away from the upper part 33, and by a sliding movement 54 for conveying the upper part 33 and a backward movement of the stitched material feeder 32. . For this purpose, the upper sewing material feeder 32 is provided with a first double-arm lever 55 attached thereto and to which a lifting and pressing bar 56 is fastened by means of a first hinge 57. The lifting and pressing bar 56 is supported by a second hinge 58 in a bearing 47 This lift and thrust rail 56 is disposed substantially in the feed direction 48 and extends from the bearing 47 toward the table 2, see Figures 2 and 4. At the end of the first two-arm lever 55 opposite the top feed 32 of sewn material, A second double-arm lever 59 is connected to the third hinge 60. This second double-arm lever 59 is pivotally mounted in its middle portion in the upper arm 4 via a fixed bearing 61. Between the third hinge 60 and the fixed bearing 61 the second double-arm lever 59 is adjustable longitudinally designed as a two-piece and adjustable by means of fastening This allows adjustment of the parallelism between the top feed stitch 32 and the table 2.

At the end of the second double-arm lever 59 opposite to the third hinge 60, a pivoting lever 63 is mounted on the second double-arm lever 59 by means of the fourth hinge 64. likewise, the second double-arm lever 59 is pivotally driven around its fixed bearing 61, whereby the top feed material stitch 32 performs reciprocating conveying movements substantially parallel to the table 2, as mentioned above. The sliding shaft 65, formed as a hollow shaft, is rotatably mounted in a bearing 66 in the upper arm 4, see Fig. 5. The sliding shaft 65 together with the pivot lever 63, the second two-arm lever 59 and the first two-arm lever 55 essentially form a displacement drive 54 .

On the push rod 37 is mounted above the first bearing bush 38 a bearing part 67, the upper side of which forms a stop 41 for the outer spring 39. Between the push rod 37 and the lifting rod 51, a crank lever 68 is mounted on this bearing part 67. the crank lever 68 has two arms 70, 71. The first arm 70 is supported by a pivotable drive lever 72, which is driven by a lifting shaft 73, which is arranged in a sliding shaft 65 formed as a hollow shaft and which has a common axis 74 with the sliding shaft 65 The first arm 70 extends approximately toward the axis 74. The second arm 71 of the knuckle lever 68 abuts the bearing surface of the lifting rod 51 formed by the pulley 75, which pulley 75 is located on the lifting rod 51 at the receiving portion 67 above the second receiving housing 52.

-4GB 291426 B6

The drive of the lift shaft 73 is effected by means of a known and commonly used lift drive 76, which is designed as an articulated mechanism shown in FIGS. 6 and 7. In this case, a crank 78, fixedly connected to the lift shaft 73, at each rotation of the shaft 6, it grips the lifting shaft 73 with a predetermined angle about the axis 74. This pivoting movement of the lift shaft 73 and hence the pivoting drive lever 72 is constant.

The swivel drive of the sliding shaft 65, which is designed as a hollow shaft, is carried out by means of the generally known and practically common shifting drive mechanism 79 shown in FIGS. 7 and 8, which is designed as a hinge mechanism adjustable during operation of the sewing machine. the second eccentric 80 is driven by the shaft 6 and is rotatably connected to the third two-arm lever 81 by means of the sixth hinge 82. The first arm 83 of the third two-arm lever 81 is rotatably coupled to a crank 84 which is rigidly connected to the sliding shaft 65 formed as a duty shaft. The second arm 85 of the third two-arm lever 81 is pivotally coupled to a slider 86 housed in a recess 87 of the adjusting shaft 89 rotatable about its axis 88. By rotating the adjusting shaft 89 about the axis 88, the path by which the slider 86 can be fully rotated 6, and thus during one movement of the second eccentric 80 back and forth, moved back and forth. In this way, the angle by which the sliding shaft 65 and hence the pivoting lever 63 swings during one revolution of the shaft 6 is varied. Similarly, the conveying path which the upper material feed feeder 32 has to travel in engagement with the upper piece 33 is adjusted. of this upper part 33.

All joints are pivotable about axes that are parallel to axis 74.

The operating mechanism of the sewing material feed device will now be described according to the schematic representation of FIG. 9. The foot 36 itself urges the parts 30, 33 lying on top of each other in the feed direction 48 toward the plate 26. While the needle 23 is stuck into the parts 30, 33 to form the stitch, there is no transport of the parts 30, 33 via the feeders 29, 32 of the sewn material. The feed material feeders 29, 32 are located in a downward or upwardly offset idling motion facing the sewing direction 31. During this idle movement, the pivot lever 63 is swiveled by the sliding shaft 65 formed as a hollow shaft in the clockwise direction (FIGS. 2 and 9) so that the first two-arm lever 55 moves together with the top feed stitch 32 against the sewing direction 31. 2 and 9 to the right. During this idle movement, the pivot drive lever 72 drives the lift shaft 73 counterclockwise (FIGS. 2 and 9) and rotates the crank lever 68 clockwise to lift the lift rod 51 counterclockwise and over the lifting and pressing bar 56 lifts the first two-arm lever 56 with the upper material feeder 32 from the parts 30, 33. As the lifting rod 51 is supported over the bearing 47 against the inner spring 45, the lifting rod 51 and thereby the upper feeder 32 are sewn. Since the crank lever 68 is supported by a push rod 37 supporting the foot 36, the foot 36 will thus be pressed against the parts 30, 33 in the direction of the table 2 not only by a constant spring 39, but additionally It is of particular importance that during the phase in which the parts 30, 33 of the " When the stitch is tightened, i.e. during the withdrawal of the needle 23 from the parts 30. 33, a higher force is exerted on the parts 30, 33 by which the parts 30, 33 are pressed against the plate. 26.

When the needle 23 is withdrawn from the parts 30, 33 back to the position shown in FIG. 2, the top sewing material feeder 32 rests on the parts 30, 33 again. For this purpose, the pivot drive lever 72 is pivoted by the lifting shaft 73 clockwise. 2 and 9, thereby pivoting the crank lever 68 also in a clockwise direction. The lifting rod 51 is moved together with the crank lever 68 by the force of the inner spring 45 in the feed direction 48, whereby the upper suture feeder 32 again rests on the upper part 33. The lower suture feeder 29 simultaneously sits on the lower part 30 from below. the upper feeder 32 of the sewn material is pressed against the upper part 33, it is given by the bias of the inner spring 45.

291426 B6 is thereby relieved of the force by which the upper sewing material feeder 32 is pressed against the parts 30, 33. The upper sewing material feeder 32 now moves in the sewing direction 31 while conveying the upper part 33. At the same time the lower sewing material feeder 29 transports the lower part 30, wherein, as already mentioned, the transport movement of the upper material feeder 32 is greater than the transport movement of the lower material feeder 29. For the transport movement of the sewing material upper feeder 32, the pivot lever 63 is swiveled by the sliding shaft 65 counterclockwise, see FIGS. 2 and 9, thereby moving the sewing material upper feeder 32 in the sewing direction 31 - hence in FIGS. . At the end of this conveying movement, the first two-arm lever 55 with the top sewing material feeder 32 is lifted as described above.

During the conveying movement of the sewing material feeder 32, the sewing material feeder 32 exerts no longitudinal force in the feed direction 48 on the push rod 37 carrying the foot 36. This is beneficial when the upper part 33 is pulled in because the foot 36 is unloaded compared to the sewing itself. During the idle movement of the sewing material upper feeder 32, the lifting drive 53 exerts a longitudinal force acting in the feed direction 48 on the push rod 37 supporting the foot 36, so that the force holding the parts 30, 33 increases. As the shoe 36 abuts against the parts 30, 33, the distance between the foot 35 of the shoe 36 and the plate 26 increases as the thickness of the parts 30, 33 increases. This also causes a corresponding lifting of the bearing part 67 by crank lever 68. the lever 72 on the first arm 70 of the knuckle 68 and the axis 69a of the fifth hinge 69 on the knuckle 68 decreases with increasing thickness of the parts 30, 33. The smaller this distance a, the greater the deflection of the crank lever 68 over the constant deflection of the pivot drive lever 72. When the thickness of the parts 30, 33 is greater, the lifting movement of the top feed 32 of the sewn material is less. That is, even thicker parts 30, 33 can be flawlessly sewn because, as already mentioned, the stroke of the top feed material stitch 32 increases with the lifting of the receptacle 67.

The stitched material feeder 32 and the foot 36 are arranged on mutually independent guide rods, i.e. on the lifting rod 51 and the push rod 37. This reduces the interaction of the pressing device 37a and the stitching material feeder 32. The upper device for moving the sewn material has only joints outside the upper arm 4. Thus, the sewing material feed device can be well lubricated using suitable bearing materials, i.e. the sewing material feed device is almost maintenance-free and moreover suitable for high sewing speeds with more than 4000 stitches per minute .

PATENT CLAIMS

Claims (5)

Sewing machine with an upper arm (4), with a rotatably driven shaft (6) arranged in the upper arm (4), with a needle bar (13) supporting the needle (23), driven by the shaft (6) and sliding up and down an upper arm (4), with a base plate (5) having a puncture opening (25) through which the needle (23) extends, arranged in the base plate (5) below the needle (23), and 291426 B6 with a sewing material upper device arranged in the upper arm (4), the sewing material upper device being provided with a thrust device (37a) formed by a push rod (37) sliding downwardly linearly in the direction ( 48) of the feed and loaded with the first spring in the feed direction (48) to the puncture opening (25), and the foot (36) located on the push rod (37) at the puncture opening (25), a lifting drive (53) for the sewing material upper feeder (32) provided with a pivotally driven lifting shaft (73) and a lifting drive coupling connecting the lifting rod (51) to the lifting shaft (73) with a shifting drive (54) for the upper the sewn material feeder (32) provided with a pivotably driven pusher feed shaft (65) and a pusher drive coupling connecting the sewn material feed feeder (32) to the pusher shaft (32). 65), characterized in that the lifting drive (53) comprises a linearly displaceable lifting rod (51) disposed adjacent to and parallel to the push rod (37) and rotatably connected thereto with the upper feeder (32) sewn the lifting rod (51) being loaded by the second spring in the direction of the puncture opening (25), and wherein the lifting drive connection is supported on the push rod (37) and loads the pushing rod (51) against the feed direction (48) a rod (37) in the direction of the puncture opening (25) by a second spring. Sewing machine according to claim 1, characterized in that the second spring in the push rod (37) is connected to a bearing (47) firmly connected to the lifting rod (51). Sewing machine according to claim 2, characterized in that the push rod (37) is at least partially designed as a hollow rod, and wherein the second spring is formed by an internal spring (45) arranged in the push rod (37) and supported by the first end o bearing (47). Sewing machine according to claim 3, characterized in that the inner spring (45) is supported by the other end on the set screw (42). Sewing machine according to claim 1, characterized in that the lifting drive connection comprises a crank lever (68) rotatably mounted about an axis (69a) on the push rod (37), with a first arm (70) and a second arm (71). whose first arm (70) cooperates with a pivotable drive lever (72) coupled to the lift shaft (73) and its engagement point (72a) abutting the first arm (70), wherein the distance (a) of the engagement point (72a) from the axis (69a) decreases when the push rod (37) is lifted from the puncture opening (25), and whose second arm (71) abuts the lifting rod (51). -7 CL 291426 B6 Sewing machine according to claim 1, characterized in that the lifting shaft (73) and the sliding shaft (65) are arranged concentrically in each other. Sewing machine according to claim 1, characterized in that the first spring is formed by an outer spring (39), which on one side is supported by a push rod (37) and on the other side by an adjustable support (40), adjustable relative to the upper arm (4).