DE102007026651A1 - Sewing machine and operating method for such a sewing machine - Google Patents

Abstract

A sewing machine has a transport device (14) for the intermittent feed of sewing material. The transport device (14) has at least one upper feed dog (15) and at least one lower feed dog (16, 17) for the intermittently frictional feed contact with a top or bottom side of the sewing material. To adjust a feed length of the transporters (15 to 17) serve mechanical top feed and bottom feed adjustment. These adjusting devices are connected to the bottom feed adjusting drive and the top feed adjusting drive in signal connection and have a storage device. In this data to be processed sewing sequences and these sewing sequences are assigned setting data for independent control of the adjustment stored during the execution of the sewing sequence. The result is a sewing machine, in which the flexibility of the Nähgutvorschubs is increased to adapt to different sewing requirements.

Description

The The invention relates to a sewing machine with a transport device for the intermittent feed of sewing material according to the generic term of claim 1. Furthermore, the invention relates to various operating methods for such a sewing machine.

A sewing machine of the type mentioned is known from the EP 0 512 145 B1 , There, a stitch length adjustment is described by corresponding change of feed values of an upper and a lower conveyor.

Lots, especially demanding sewing tasks require one more flexible adjustment of the sewing material feed to the respective Sewing conditions than this by the well-known sewing machines can be guaranteed.

It It is therefore an object of the present invention to provide a sewing machine of the type mentioned in such a way that the flexibility the sewing material feed to adapt to different sewing requirements is increased.

These The object is achieved by a sewing machine with the features specified in claim 1.

According to the invention was realized that it is possible, the already known Mechanism for changing the feed length of a lower and an upper transporter by the use of appropriate Automate adjustment drives. The feed length change can now by controlling the corresponding adjustment over the Control device done. The control device can with external Sensors are in signal connection and / or a direct influence the adjusting drives by controls of the sewing machine, for Example footswitch, toggle or push button enable. In this way is a flexible adjustment of the Nähgutvorschubs for example, the course of a seam, possible. To the Example, the stitch length in the corner between two abutting each other over corner seams be adjusted so that the stitch ends in the corner without that the last stitch is in its length from the previous one Stitches needs to be differentiated. About the controller can such a feed length adjustment over an entire sewing sequence, with the respective Setting data for the adjustment drives are retrieved. Also an adjustment of the feed to changing material parameters, for example, to a changing composition of matter or a change of the sewing direction to the angle the warp and weft threads of the sewing material is possible. In addition to an automatic specification of different total feed lengths, ie different stitch lengths, can also be a different Ratio of the feed lengths between the upper and the lower conveyor, which is also referred to as Raff feed value is called. The change of the feed length can also be used to achieve desirable optical effects Sewing can be used.

at A sewing machine according to claim 2 can not be only the length or the ratio of the feed length of the upper transporter to the feed length of the lower Adjusting transporters, but it can also be the feed lengths of the two lower transporters with each other. This is below as a default of different Kräusel feed values designated. By the additional and controllable via the control device Underfeed adjustment allows flexibility in the specification of feed options by the sewing machine according to the invention continue to increase.

setting adjustments as adjusting devices according to claim 3 have due to their proven mechanical robustness.

A Adjusting device according to claim 4 can be with little To integrate construction effort into a sewing machine.

One Stepper motor according to claim 5 allows a finely predetermined Feed adjustment.

A Housing the adjusting drive according to claim 6 leads to a compact sewing machine.

A Embodiment according to claim 7 allows an automatic Adjustment of the thread tension in particular to one over the Control device predetermined stitch length.

A Another object of the invention is to provide operating methods for to specify the sewing machine according to the invention.

These The object is achieved by the operating methods according to claims 8 and 9 and what the sewing machine according to claim 2, by an operating method according to claim 10.

The Advantages of these operating methods correspond to those described above already with reference to the invention Sewing machine have been explained.

One Embodiment of the invention will be described below explained in detail the drawing. In this show:

1 a side view of a sewing machine with a base plate;

2 a top view of the sewing machine 1 ;

3 a bottom view of the sewing machine after 1 ;

4 an end view of the sewing machine according to viewing direction IV in 3 ;

5 a section along line VV in 3 ;

6 a section according to line VI-VI in 2 ;

7 a section according to line VII-VII in 3 ;

8th a side view of the base plate from the same direction as 1 , in comparison to 1 mechanical components are missing, leaving the mechanical coupling of a mechanical bottom feed adjusting device, this bottom feed adjusting device being in the "high lift"position;

9 a section along line IX-IX in 8th ;

10 one too 8th similar view with the bottom feed adjusting device in the "small stroke" position,

11 a section along line XI-XI in 10 ; and

12 enlarges a section 4 , wherein in particular the conveyors are shown for Nähgutvorschub.

A sewing machine 1 has an arm 2 , a base plate 3 and a stand connecting them 3a , The free end of the arm 2 carries a head 4 , In the arm 2 is an arm wave 5 stored, which is driven in rotation by a main drive not shown in detail. About the arm shaft 5 is one in the head 4 mounted needle bar 6 vertically moved up and down. At the bottom of the needle bar 6 is a needle 7 assembled. When operating the sewing machine 1 pass through the needle 7 a stitch hole in a throat plate 8th placed in a platen 9 the base plate 3 is used. Below the throat plate 8th is one for looping with the needle 7 arranged cooperating gripper, which is driven by a gripper shaft and a deflection gear, which are not shown in detail. The drive of the gripper is also from the arm shaft 5 derived. A fabric presser serves to fix the sewing material during stitch formation 11 , the lower end of a fabric presser bar 12 is mounted.

For the intermittent feed of the sewing material in a sewing direction 13 that with an arrow in the 12 is shown and in the 12 from right to left, serves a transport device 14 whose frictionally cooperating with the fabric transporters increased in the 12 are shown. With an upper side of the sewing material acts an upper feed dog 15 together, in the 12 on the one hand in a zero position and on the other hand at 15 ' is shown in one of these opposite to the left shifted maximum stroke position.

With a bottom of the fabric come two lower conveyors, namely a first lower conveyor 16 and a second lower transporter 17 in contact. The first lower conveyor 16 is in the 12 left and the second lower conveyor 17 is in the 12 shown on the right. The two lower transporters 16 . 17 have along the sewing direction 13 spaced-apart contact portions for frictional feed contact with the fabric underside. The transporters 16 . 17 are on the one hand in a zero position and on the other hand at 16 ' . 17 ' shown in a relation to this left shifted maximum stroke position.

For intermittent frictional feed contact with the fabric have the transporters 15 to 17 one sawtooth profiling each 18 on.

The hub of all three transporters 15 to 17 In the sewing direction can be customized for each of the transporters 15 to 17 be preset controlled. This will be described below in connection with the feed length of one of the lower conveyors 16 . 17 based on 7 to 11 explained.

To adjust the feed length is a first stepper motor 18 that stuck to the base plate 3 is mounted. The first stepper motor 18 stands with the first lower conveyor 16 in active connection. With a drive shaft of the first stepper motor 18 rotatably connected is a plant body 19 with a spiral outer peripheral abutment wall 20 , The investment wall 20 So has a varying radius in circumferential sections. The investment body 19 represents a driven rotatable cam. The investment wall 20 lies on an adjusting or counter-body in the form of a needle bearing 21 in, in a fork-shaped deflection bar 22 is held. The needle bearing 21 So provides a slider to interact with the plant wall 20 dar. The deflection bar 22 is about a joint 23 with a backdrop adjustment body 24 connected to his Rotationally fixed with a slotted guide 25 connected is. Along the latter is a sliding block 26 displaceable. This is in turn with a triangle lever 27 connected. About an eccentric shaft 28 becomes the triangle lever 27 vibrated. Depending on the guide direction of the slotted guide 25 This vibration is in a more or less large torsional vibration of a transmission shaft 29 implemented around its longitudinal axis.

The 7 such as 10 and 11 show a lower transport adjustment 30 to which the first stepper motor 18 heard in a position "small stroke", in the operation practically no angle adjustment to the transmission shaft 29 is transmitted. When operating the sewing machine, the assigned lower transporter remains virtually in its zero position. In the position "small stroke" is the outermost end of the plant wall 20 at the needle bearing 21 on, so the latter of the drive shaft of the first stepping motor 18 is maximally spaced.

The 8th and 9 In contrast, show the position "long stroke" of the first lower transport adjustment 30 , In this position "big stroke" is the investment wall 20 with its innermost end on the needle bearing 21 so that the distance between this and the drive shaft of the stepping motor 18 is low. Between the two positions "small stroke" and "large stroke" is a relative rotation of the drive shaft of the first stepping motor 18 from about 225 °. Because the stepper motor 18 has a high step resolution, all intermediate positions between the positions "small stroke" and "large stroke" virtually infinitely specify.

In the position "big stroke" is the sliding block 26 in the slide tour 25 in one in the 9 approximately guided at a 45 ° angle obliquely upwardly extending guide direction. This will affect the transmission shaft 29 transmit a maximum turn-angle adjustment. The associated lower feed dog is then between the stitches between the zero position and the respective, in the 12 shifted position shown "big stroke".

In intermediate positions of the first lower transport adjusting device 30 between the illustrated positions "small stroke" and "large stroke" is corresponding to the first lower feed dog 16 between its zero position and a position located between the zero position and the "high lift" position 12 shown maximum feed and the feed zero are depending on the position of the first stepping motor 18 also all intermediate positions possible.

A second lower transport adjustment device 31 serves for the controlled specification of the feed length of the second lower conveyor 17 , The second lower transport adjustment device 31 has a second stepper motor 32 who is also at the base plate 3 under the platen 9 is mounted. The second stepper motor 32 stands with the second lower conveyor 17 in active connection. The mechanical control of the second lower feed adjusting device 31 corresponds to that of the first lower feed adjusting device 30 and is constructed the same as this one with the difference that the second bottom feed adjusting device 31 on a transmission shaft 33 acts in the executed as a hollow shaft transmission shaft 29 the first bottom feed adjusting device 30 runs and independently of this about a common longitudinal axis of the two waves 29 . 33 is rotated by a predetermined angle amount for feed control.

The transmission waves 29 . 33 act independently of each other on one of the lower conveyors 16 and 17 , It can be about the rotation of the second stepping motor 32 the feed length of the second lower feed adjusting device 31 set lower driven conveyor pretend, as described above in connection with the first lower feed adjustment 30 was explained.

The 5 shows the second lower feed adjusting device 31 in a position similar to that of the first lower feed adjusting device 30 after the 10 and 11 corresponds, ie in the position "small stroke" by rotation of the second stepper motor 32 may be the second bottom feed adjusting device 31 practically continuously changed to the position "long stroke".

For adjusting a feed length of the upper feed dog 15 serves an upper transport adjustment 34 , This has a third stepper motor 35 who is also at the base plate 3 attached and under the platen 9 is mounted. The third stepper motor 35 stands with the upper conveyor 15 in active connection. The mechanical transmission from the stepper motor 35 on the upper conveyor 15 corresponds to the one described above with reference to the two bottom feed adjustment devices 30 . 31 was explained. In contrast to the bottom feed adjusting devices 30 . 31 has the top transporter adjustment device 34 as transfer element between the needle bearing 21 and the scenery adjustment body 24 a pull rod 36 standing in the stand 3a runs. Depending on the rotational position of the third stepper motor 35 is a corresponding angle adjustment to a transmission shaft 37 the top transport adjustment 34 mediated, in turn, mechanically via a push rod 37a with the upper conveyor 15 connected is. The transmission wave 37 runs along the arm 2 ,

The three stepper motors 18 . 32 . 35 are all within one the base plate 3 housed surrounding and not shown in the drawing housing the sewing machine.

One in the 1 schematically indicated control device 38 stands with the two bottom feed adjusting devices 30 . 31 and the top feed adjusting device 34 in signal connection. The control device 38 has a storage facility 39 , in which data are to be processed sewing sequences and this sewing sequence data assigned setting data for controlling the stepper motors 18 . 32 . 35 are stored during execution of the sewing sequence.

Due to the independent adjustment possibilities of the feed lengths of the conveyors 15 to 17 about the adjustment 30 . 31 and 34 can be realized adjustment, which include the following main adjustment options:
On the one hand, the feed lengths of all three transporters 15 to 17 synchronously adjust each other in the same way, so that all three transporters 15 to 17 be adjusted from a first common feed length to a second common feed length. In this case, so the entire transport feed of the sewing machine 1 and thus the stitch length changed.

Secondly, it is possible to feed the two lower conveyors 16 . 17 to adjust synchronously with each other, wherein the feed length of the upper conveyor either remains constant or one of the change in the feed length of the lower conveyors 16 . 17 different amount is changed. By such an adjustment so the difference between the realized during a transport stroke transport on the one hand, the lower conveyors 16 . 17 and on the other hand, the upper transporter 15 changed. This is hereinafter referred to as differentiability of the transport of the sewing machine 1 or as a change in the Raff feed value. Due to this differentiability, a change in the gathering of an upper workpiece part, which from the upper conveyor 15 is transported, relative to a lower work piece, which of the lower conveyors 16 . 17 transported.

Third, it is possible only the feed lengths of the two lower conveyors 16 . 17 to adjust relative to each other. This can cause a change in one of the lower conveyors 16 . 17 induced crimping of a lower workpiece part during transport can be varied. This adjustable property of the fabric transport through the sewing machine 1 is hereinafter referred to as a differential or as a change of the Kräusel feed value.

Also any overlays of these three principal adjustment options "change the feed length "," differentiability "and" differential " are possible.

In a first exemplary method of operation of the sewing machine 1 First of all, it is activated by the corresponding synchronous control of all three stepper motors 18 . 32 . 35 controlled by the control device 38 , a first feed value for feeding the material with the conveyors 15 to 17 specified. Subsequently, the sewing material, as long as this first default value is set, so with a first stitch length, sewn. Subsequently, a second, different from the first feed value for Nähgutvorschub with the transporters 15 to 17 by concurrent control of the stepper motors 18 . 32 . 35 specified. Subsequently, the sewing material is sewn with the resulting second feed value, which may for example be greater than the first feed value, so that the subsequent seam has a greater stitch length than before.

This controlled conversion of the feed value can be dependent, for example, on detected signal values of additional sensors on the sewing machine 1 carried out, for example, a light barrier sensor or a touch sensor, which detects when an end of the fabric is reached and therefore only a few stitches are to be sewed to the seam end, so is ensured by adjusting the stitch length that the last stitch in a given location ends without this last stitch being too different in length from the previous stitches. Such a difference is undesirable for optical reasons. Even when sewing corner stitching this can be a stitch shortening can be prevented in the corner.

Depending on the specified stitch length is controlled by the control device 38 , also adjusted the thread tension automatically. For this purpose, the control device controls 38 an electronic thread tension sensor of the sewing machine 1 at. In this case, the thread tension is increased in particular as the stitch length is increased.

In a further, alternatively or additionally usable operating method for the sewing machine 1 the differentiability is exploited. Here, first, a first Raff feed value for feeding the material with the conveyors 15 to 17 given, with the upper feed dog 15 z. B. makes a Nähgutvorschub, by the Nähgutvorschub the lower conveyors 16 . 17 is different. Subsequently, the fabric is sewn with this first Raff feed value. Subsequently, by appropriate adjustment of either the stepper motor 35 for the upper conveyor 15 or concurrent adjustment of the stepper motors 18 . 32 for the two lower conveyors 16 . 17 a second, predetermined by the first different Raff feed value. This can for example be done so that at the second Raff feed value of the difference in the feed between the upper feed dog 15 and the two lower transporters 16 . 17 is bigger than before. Now the fabric is gathered harder during the subsequent sewing than before. This can be used, for example, to achieve desired optical results during sewing or to compensate for a change in the shirring behavior of the fabric, for example when sewing seams with a change in direction for fabrics with preferred friction directions.

In another method of operation, which alternatively or in addition to the above-mentioned operation method in the sewing machine 1 can be performed, the differential is exploited. Here, first, a first Kräusel feed value for advancing the material with the two lower conveyors 16 . 17 predetermined, where z. B. the first lower conveyor 16 performs a Nähgutvorschub that of the Nähgutvorschub the second lower conveyor 17 is different. In particular, at the first crimp feed value, the feed is the second lower feed dog 17 delivers, slightly larger than that of the first lower feed dog 16 supplies. The fabric is now sewn with this first crimp feed value. Subsequently, by appropriate driving, for example, one of the two stepper motors 18 . 32 for the lower transporters 16 . 17 a second crimp feed value is specified which differs from the first crimp feed value. The changeover can for example be such that the difference in feed between the two lower conveyors 16 . 17 now larger than before, so that the lower work piece now by the two lower conveyors 16 . 17 is more curly. Subsequently, the fabric is sewn with the second crimp feed value. This third method of operation can also be used to achieve certain optical results when sewing or to compensate for a change in the properties of the material during sewing, in particular when sewing seams with changes in direction.

amendments of sewing material parameters by changing the Differentiability or the differential are taken into account For example, changes may be in the binding style of the sewing material, changes in the raw material composition of the Material or changes in the degree of twist of the warp and weft threads with each other.

The activation of the stepper motors 18 . 32 . 35 can automatically by the control device 38 when processing a sewing program or sewing sequence. Alternatively or additionally, it is possible to enable this control directly, for example via a foot switch or a toggle or a button by the operator. The operator can therefore change the stitch length, the differentiability or the differential as needed during sewing. Such a direct control is possible in particular for making quick corrections, which is often desirable, for example, when sewing in sleeves. Here, for example, blank tolerances can be compensated.

Especially can be changes in sewing behavior due a change in the angle of the sewing direction between compensate for the warp and weft direction of the sewing material. Such compensation can, for example, when sewing bent seams made continuously adjusted.

alternative to a control of the feed change over external sensors can also do this depending on internal parameters, for example, the number of stitches sewn or sewn Seam line, done.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 0512145 B1 [0002]

Claims (10)

Sewing machine ( 1 ) - with a transport device ( 14 ) for the intermittent feed of sewing material, comprising - at least one upper conveyor ( 15 ) for intermittently frictional feed contact with an upper side of the sewing material, - at least one lower conveyor ( 16 . 17 ) for intermittently frictional feed contact with a bottom side of the sewing material, - with a mechanical top feed adjusting device ( 34 ) for adjusting a feed length of the at least one upper conveyor ( 15 ), - with a mechanical bottom feed adjusting device ( 30 . 31 ) for adjusting a feed length of the at least one lower conveyor ( 16 . 17 ), - with an upper transport adjustment drive ( 35 ) for adjusting the top feed adjusting device ( 34 ), - with a bottom feed adjustment drive ( 18 . 32 ) for adjusting the lower transport adjusting device ( 30 . 31 ), characterized by a control device ( 38 ) connected to the bottom feed adjustment drive ( 18 . 32 ) and the top transport adjustment drive ( 35 ) is in signal connection and a memory device ( 39 ), in the data to be processed sewing sequences and this sewing sequence data assigned setting data for independent control of the adjustment drives ( 18 . 32 . 35 ) are stored during execution of the sewing sequence. Sewing machine according to claim 1, characterized in that the transport device ( 14 ) additionally comprises: - at least one further lower conveyor ( 17 . 16 ) for the intermittently frictional feed contact with the underside of the sewing material, - wherein the two lower conveyors ( 16 . 17 ) along a sewing direction ( 13 ) spaced apart contact portions for feed contact with the underside of the fabric, - with a further mechanical bottom feed adjusting device ( 31 . 30 ) for adjusting a feed length of the further lower conveyor ( 17 . 16 ), - with another lower transport adjustment drive ( 35 . 32 ) for adjusting the further lower transport adjusting device ( 31 . 30 ), - wherein the control device ( 38 ) also with the further lower transport adjustment device ( 31 . 30 ) is in signal connection, and - wherein in the memory device ( 39 ) associated with the data to be processed sewing sequences this Nähsequenzdaten more adjustment data for controlling also the further Untertransport-Verstellantriebs ( 35 . 32 ) are stored during execution of the sewing sequence. Sewing machine according to claim 1 or 2, characterized in that the adjusting devices ( 30 . 31 . 34 ) are designed as gate adjustments and at least one along the adjusting device ( 18 . 32 . 35 ) adjustable gate adjuster ( 24 ) exhibit. Sewing machine according to claim 3, characterized in that at least one of the adjusting devices ( 30 . 31 . 34 ) one via the associated adjusting drive ( 18 . 32 . 35 ) driven rotatable cam ( 19 ) with a peripheral surface ( 20 ) having circumferentially varying radius, wherein with the peripheral surface ( 20 ) an adjusting body ( 21 ) mechanically connected to the associated conveyor ( 15 to 17 ) is coupled in sections to the feed length adjustment cooperates. Sewing machine according to one of claims 1 to 4, characterized by a stepping motor ( 18 . 32 . 35 ) as adjusting drive. Sewing machine according to one of claims 1 to 5, characterized in that the at least one adjusting drive ( 18 . 32 . 35 ) in a housing of the sewing machine ( 1 ) is housed. Sewing machine according to one of claims 1 to 6, characterized in that the control device ( 38 ) is connected to a yarn tension sensor. Operating method for a sewing machine according to one of claims 1 to 7 with the following steps: - specification of a first feed value for advancing the material to be sutured with the at least one upper conveyor ( 15 ) and the at least one lower conveyor ( 16 . 17 ), - Sewing of the sewing material with the first feed value, - Specification of a second, different from the first feed value for feeding the material with the at least one upper feed dog ( 15 ) and the at least one lower conveyor ( 16 . 17 ), - Sewing of the sewing material with the second feed value. Operating method for a sewing machine according to one of Claims 1 to 7, having the following steps: - Specification of a first gather feed value for feeding the sewing material with the at least one upper conveyor ( 15 ) and the at least one lower conveyor ( 16 . 17 ), wherein the first Raff feed value the ratio of the feed lengths of the upper conveyor ( 15 ) to the lower conveyor ( 16 . 17 ), - sewing of the sewing material with the first Raff feed value, - specification of a second, different from the first Raff feed value for feeding the fabric with the at least one upper conveyor ( 15 ) and the at least one lower conveyor ( 16 . 17 ), - Sewing of the sewing material with the second Raff feed value. Operating method for a sewing machine according to one of Claims 2 to 7, having the following steps: - Specification of a first crimp feed value for advancing the material to be stitched with the two lower conveyors ( 16 . 17 ), wherein the first crimp feed value the ratio of the feed lengths of a lower conveyor ( 16 ) to the other bottom conveyor ( 17 ), - sewing of the sewing material with the first crimping feed value, - specification of a second, different from the first crimping feed value for advancing the sewing material with the two lower conveyors ( 16 . 17 ), - sewing the fabric with the second crimp feed value.