DE102022203472A1 - sewing machine - Google Patents

Abstract

A sewing machine (1) has a needle bar (6) for holding a sewing needle (5) for guiding an upper thread. A stitch plate of the sewing machine (1) has an opening for the sewing needle (5) to pass through during stitch formation. A presser foot (8) is used to fix sewing material in the area of the stitch plate during stitch formation. A needle bar rotary drive (14) is used to rotate the needle bar (6) about a needle bar axis. The result is a sewing machine with which flexible sewing operation, in particular with changing sewing direction, is possible, which enables processing of CNC control programs in particular.

Description

The invention relates to a sewing machine.

Sewing machines are known, for example, from EP 3 392 388 A1 , the EP 2 028 311 A2 and the DE 199 51 127 C2 .

It is an object of the present invention to develop a sewing machine of the type mentioned in such a way that flexible sewing operation, in particular with changing sewing direction, is possible, which enables processing of CNC control programs in particular.

This object is achieved according to the invention by a sewing machine with the features specified in claim 1.

According to the invention, it was recognized that it is possible to provide a sewing machine with a needle bar rotary drive for specifying a sewing direction, without having to do without a presser foot for fixing the sewing material during stitch formation. The result is a sewing machine with a flexibly predeterminable sewing direction, with the sewing material being securely fixed by the pressure foot during sewing. The sewing machine has a sewing drive for specifying a stitch formation movement of the needle bar that runs along the needle bars. A choice of sewing direction results from the rotational orientation of the needle bar relative to the throat plate. This allows flexible seam geometries to be ensured, which can be used in particular when processing sewing programs, especially controlled via a CNC control. In particular, automatic sewing of seams that run along path curves is possible.

The presser foot can be designed as a transport foot.

A rotation-proof mounting of the presser foot on the needle bar according to claim 2 ensures that a position of the presser foot automatically adapts to the sewing direction selected via the needle bar rotation.

A lifting drive according to claim 3 enables the sewing operation to be adapted to sewn material of different thicknesses. A stroke height of the stroke adjustment can be in the range between 0.5 mm and 50 mm, for example in the range between 5 mm and 10 mm.

A lifting drive according to claim 4 allows precise stroke adjustment. The lifting drive can be designed as a stepper motor. The lifting drive can be controlled via a control program.

A turntable according to claim 5 makes it possible to mount drive components of the lifting drive fixed to the frame, so that the needle bar rotary assembly rotates relative to these drive components fixed to the frame when the needle bar rotary drive is adjusted. The connection of the lifting drive to the needle bar rotating assembly for stroke displacement can be provided via a circumferential groove in the turntable.

A further object of the invention is to develop a sewing machine in such a way that a sewing direction can be flexibly specified even for two-thread sewing.

This object is achieved according to the invention by a sewing machine with the features specified in claim 6.

A sewing drive can in turn be used for the stitch-forming movement of the needle bar, whereby the gripper sewing drive for the stitch-forming movement of the hook and the sewing drive for the stitch-forming movement of the needle bar can be derived from one and the same drive source.

The needle bar rotary drive and the hook assembly rotary drive ensure that both the needle bar and the hook assembly interact correctly with each other to form two-thread stitches, regardless of a current rotational position and therefore regardless of the current sewing direction.

In particular, a two-thread lockstitch can be sewn with the sewing machine.

The needle bar rotary drive can work synchronized with the hook assembly rotary drive. The needle bar rotary drive can work synchronized with the sewing drive.

A relative orientation of the gripper axis to the gripper assembly axis according to claim 7 enables the use of a gripper that rotates about a gripper axis that runs parallel to a needle bar axis. The spacing of the gripper assembly axis from the gripper axis makes it possible to ensure the correct position of the gripper in relation to the needle bar for correct stitch formation, regardless of the sewing direction set via the rotary drives.

A differential gear unit according to claim 8 allows an adjustment of a relative rotational position of a gripper tip of the gripper about the gripper axis depending on the rotational position of the gripper assembly about the gripper assembly axis. This ensures that the gripper not only with regard to the arrangement of the entire gripper is correctly oriented to a puncture point of the needle tip, but also that the gripper tip is synchronized in the correct phase for stitch-forming interaction with the sewing needle in place, regardless of the instantaneous position set via the rotary drives.

An embodiment with a common rotary drive motor for the needle bar rotary drive on the one hand and the Geifer assembly rotary drive on the other hand according to claim 9 is cost-reducing, and the drives associated with it can always move in the correct phase. Synchronicity between the needle bar rotary drive and the gripper assembly rotary drive can then be ensured via a mechanical coupling with the common drive motor.

A deflection gear according to claim 10 enables a flexible drive force transmission to the output-side components of the needle bar rotary drive on the one hand and the Geifer assembly rotary drive on the other hand.

The design features of the sewing machine explained above can be used in any combination. For example, the sewing machine with the needle bar rotary drive and the presser foot can also have a gripper assembly rotary drive.

• 1 eine bedienerseitige perspektivische Ansicht einer Nähmaschine mit einem Nadelstangen-Drehantrieb zum Drehen einer Nadelstange und eines Drückerfußes um eine Nadelstangenachse und mit einem Greifer-Baugruppen-Drehantrieb zum Drehen einer Greifer-Baugruppe um eine nicht mit einer Greiferachse zusammenfallende Greifer-Baugruppen-Achse;
• 2 vergrößert und in einem Details des Nadelstangen-Drehantriebs zeigenden Ausschnitt eine Ansicht gemäß Blickrichtung II in 1, wobei der Drückerfuß auf ein Niveau einer Stichplatte der Nähmaschine abgesenkt ist;
• 3 in einer zu 2 ähnlichen Darstellung die Nähmaschine mit dem auf ein erhöhtes Niveau angehobenem Drückerfuß;
• 4 aus einer Blickrichtung ähnlich der 1 vergrößert Details sowohl des Nadelstangen-Drehantriebs als auch des Greifer-Baugruppen-Drehantriebs in einem Stichbildungsbereich mit der Nadelstange und einem Greifer in einer Dreh-Grundstellung „0°“ entsprechend der 1;
• 5 in einer zu 4 ähnlichen Darstellung den Nadelstangen-Drehantriebs und den Greifer-Baugruppen-Drehantrieb in einer im Vergleich zur 4 um 90° entgegen dem Uhrzeigersinn verdrehten Drehstellung „90°“;
• 6 eine Getriebebaugruppe des Greifer-Baugruppen-Drehantriebs einschließlich eines Greifer-Nähantriebs zum Drehen des Greifers um eine Greiferachse;
• 7 in einer zur 6 ähnlichen, perspektivischen Darstellung die Baugruppe nach 6 mit abgenommenen Gehäusekomponenten;
• 8 eine bedienerseitige Ansicht von Hauptkomponenten der Nähmaschine mit zusätzlicher Veranschaulichung einer Zahnriemen-Führung zum Antrieb des Nadelstangen-Drehantriebs.

An exemplary embodiment of the invention is explained in more detail below with reference to the drawings. In this show:

• 1 an operator-side perspective view of a sewing machine with a needle bar rotary drive for rotating a needle bar and a presser foot about a needle bar axis and with a hook assembly rotary drive for rotating a hook assembly about a hook assembly axis that does not coincide with a hook axis;
• 2 enlarged and in a detail showing a detail of the needle bar rotary drive, a view according to viewing direction II in 1 , wherein the presser foot is lowered to a level of a throat plate of the sewing machine;
• 3 in one too 2 Similar representation of the sewing machine with the presser foot raised to a higher level;
• 4 from a viewing direction similar to that 1 enlarges details of both the needle bar rotary drive and the hook assembly rotary drive in a stitch forming area with the needle bar and a hook in a "0°" rotation home position corresponding to the 1 ;
• 5 in one too 4 Similar representation of the needle bar rotary drive and the hook assembly rotary drive in a comparison to the 4 rotated 90° counterclockwise to the “90°” position;
• 6 a gear assembly of the hook assembly rotary drive including a hook sewing drive for rotating the hook about a hook axis;
• 7 in one to 6 Similar, perspective view of the assembly 6 with housing components removed;
• 8th an operator-side view of the main components of the sewing machine with an additional illustration of a toothed belt guide for driving the needle bar rotary drive.

A sewing machine 1 (cf. 1 ) has a C-shaped basic structure with an arm 2, a base plate 3 and a stand 4 connecting the arm 2 and the base plate 3.

The sewing machine 1 has stitch forming tools in the form of a sewing needle 5, which is held by a needle bar 6, and a gripper 7. The needle bar 6 is mounted in a bearing sleeve 6b via several sliding blocks 6a.

The sewing needle 5 is used to guide an upper thread. A stitch plate 5a of the sewing machine 1 has an opening for the sewing needle 5 to pass through during stitch formation.

A presser foot 8, also known as a sewing foot, is used to fix sewing material in the area of the needle plate during stitch formation. The needle bar 6 and the presser foot 8 are mounted on a head 2a of the sewing machine 1, which forms an end portion of the arm 2.

The presser foot 8 can also perform a hopping movement synchronously with the sewing drive. This hopping movement can be specified via the lifting drive 10. A hopping stroke in this hopping movement can be in the range between 0.5 mm and 10 mm.

The gripper 7 is mounted under the throat plate in the base plate 3. A gripper axis 9, around which the gripper 7 rotates when forming the stitch, runs vertically (see for example 7 ).

The gripper 7 is used to guide a stitch that interacts with the upper thread during stitch formation the bobbin thread and has a bobbin thread supply in the form of a spool.

To make it easier to display positional relationships, a Cartesian xyz coordinate system is used below. The x-direction runs along a sewing direction 2 to the left. The y-direction is horizontal in the 1 to the left and perpendicular to the drawing plane 2 . The z direction runs vertically in the 1 and 2 up.

The sewing machine 1 has a lifting drive 10 for adjusting the stroke of the presser foot 8 along the z-direction. 2 shows the presser foot 8 in a lifting position lowered to the level of the throat plate. 3 shows the presser foot 8 in a position compared to the lifting position 2 raised lifting position.

The lifting drive 10 has an actuator that can be designed as a stepper motor. A gear ring, not shown in the drawing, is placed on a motor shaft of the lifting drive 10 and interacts with a rack section of a presser foot rod 11 of the presser foot 8. A pusher end 12 that interacts with the material to be sewn is also designed as a sleeve for the sewing needle 5 to pass through.

As an alternative to the separate implementation of a stepper motor lifting drive 10, a lifting adjustment of the presser foot can also be derived from an arm shaft of the sewing machine 1.

A rotary drive motor 13, which is mounted on the base plate side, provides a common drive source on the one hand for a needle bar rotary drive 14 for rotating the needle bar 6 and the presser foot 8 about a vertical needle bar axis 15 and on the other hand for a gripper assembly rotary drive 16 for rotating a Gripper assembly 17 containing gripper 7 about a gripper assembly axis 18 (cf. for example 7 ). The gripper assembly axis 18 runs parallel to the gripper axis 9 and is spaced apart from it. Both axes 9, 18 run parallel to the z-axis, i.e. vertically. The gripper assembly axis 18 coincides with the needle bar axis 15.

To rotate the needle bar 6 and the presser foot 8 connected to it in a rotationally fixed manner about the needle bar axis 15, the rotary drive motor 13 is in operative connection via a toothed belt 19 with a rotary drive shaft 20, which runs along the y-axis (cf. 8th ). The rotary drive shaft 20 is in operative connection with a toothed ring 22 on the needle bar side with a vertical axis of rotation via a further toothed belt 21, which is initially guided along the stand 4 and then along the arm 2. On the one hand, the needle bar 6 and, on the other hand, the presser foot bar 11 are connected in a rotationally fixed manner to the toothed ring 22 on the needle bar side.

A thread lever assembly 23 is arranged in the head 2a above the needle bar 6 (cf. 1 ). This is designed in such a way that, regardless of the rotational position of the needle bar 6 about the needle bar axis 15, it ensures that the upper thread is knotted with the lower thread when forming the stitches and that the thread is pulled correctly. A thread tension plate 25 is mounted on the arm 2 of the sewing machine 1 adjacent to a thread lever 24 of the thread lever assembly 23. Tensioning units 26 for specifying a thread tension of the upper thread, which is not shown in the drawing, are mounted on the thread tension plate 25.

A needle bar rotating assembly 27, which, in addition to the needle bar 6, has the presser foot 8 connected to it in a rotationally fixed manner about the needle bar axis 15, also includes a turntable 28, the central disk axis of which coincides with the needle bar axis 15 (cf. for example 2 ). This turntable 28 is in the 2 and 3 shown in a side view. The turntable 28 is connected to the ring gear 22 and to the needle bar 6 in a rotationally fixed manner. The turntable 28 is firmly connected to the presser foot 8.

The lifting drive 10 is fixed to a frame of the sewing machine 1, namely to a head-side frame element. The turntable 28 has one in the 2 indicated circumferential groove 29, into which a driver 30 of the presser foot rod 11 engages to shift the stroke of the presser foot 8. Alternatively, the lifting drive 10 can be connected to the turntable 28 via a shoulder.

To rotate the gripper assembly 17 about the gripper assembly axis 18, the rotary drive shaft 20 is operatively connected to a ring gear of a hollow shaft section 32 via a further toothed belt 31. This hollow shaft section 32 is in operative connection via a pair of gears 34, 35, a gear shaft 36, another pair of gears 37, 38 with a spur toothing 39 of an assembly housing 40 of the gripper assembly 17.

The gripper 7 can be rotated about the gripper axis 9 in the assembly housing 40. The assembly housing 40 in turn can be rotated about the gripper assembly axis 18.

Via the gear connection 32 to 39, a rotation of the hollow shaft section 32 about an axis parallel to the y-axis is deflected into a rotation of the assembly housing 40 about the gripper assembly axis 18 parallel to the z-axis.

An up and down movement of the needle bar 6 parallel to the z-axis and a rotation of the gripper 7 about the gripper axis 9, each for stitch formation, is derived from a sewing drive motor 41, which is also mounted on the base plate side. The latter interacts with a core shaft 43 of the gripper drive shaft 33 via a toothed belt 42. A locking clutch 42b is arranged between a toothed ring 42a, on which the toothed belt 42 engages, and the core shaft 43, which separates the core shaft 43 from the sewing drive motor 41 in overload situations.

Via a differential gear unit 44, a transmission shaft 45 and one in the 7 partially visible bevel gear 46 and a vertically extending further transmission shaft 47, the core shaft 43 is in the 7 non-visible, also vertical gripper shaft in operative connection, which is aligned with the gripper axis 9.

The differential gear unit 44 serves to adapt a relative rotational position of a gripper tip about the gripper axis 9 depending on a respective rotational position of the gripper assembly 17 about the gripper assembly axis 18. The differential gear unit 44 ensures that the transmission shaft 45 is rotated relative to the core shaft 43 is possible to enable a corresponding adjustment of the relative rotational position of the gripper tip.

The rotation of the transmission shaft 45 to the core shaft 43 by means of the differential gear unit 44 is positively controlled. Thus, depending on the rotational position of the gripper assembly 17 about the gripper assembly axis 18, the relative rotational position of the gripper tip about the gripper axis 9 is adjusted.

The sewing drive of the needle bar is ensured via the drive motor 41 on the needle bar via an arm shaft 48 and a crank deflection gear which is housed in the head 2a

4 shows the needle bar 6 with the presser foot 8 and the gripper assembly 17 in a basic rotation position “0°”, in which sewing takes place along the x-axis. A gripper tip of the gripper 7 is aligned with the needle bar axis 15.

5 shows a comparison to the rotation position 4 Rotary position rotated by 90 ° counterclockwise, which was brought about via the rotary drive motor 13, on the one hand, acting on the needle bar rotary drive 14 and, on the other hand, acting on the gripper assembly rotary drive 16. Both the needle bar rotating assembly 27 with the needle bar 6 and the presser foot 8 as well as the gripper assembly 17 are rotated synchronously with one another on the one hand about the needle bar axis 15 and on the other hand about the gripper assembly axis 18 by 90 ° counterclockwise. Due to the effect of the differential gear unit 44, even in this “90°” rotation position, it is ensured that the hook tip faces the needle bar axis 15 for correct stitch formation.

A two-thread lockstitch can be sewn with the sewing machine 1.

The components of the sewing machine 1 are in signal connection with a central control device. This can be a CNC control.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 3392388 A1 [0002]
• EP 2028311 A2 [0002]
• DE 19951127 C2 [0002]

Claims (10)

Sewing machine (1) - with a needle bar (6) for holding a sewing needle (5) for guiding an upper thread, - with a stitch plate with an opening for the sewing needle (5) to pass through during stitch formation, - with a presser foot (8) for fixing sewing material in the area of the needle plate during stitch formation - With a needle bar rotary drive (14) for rotating the needle bar (6) about a needle bar axis (15) running along the needle bar. sewing machine in Claim 1 , characterized in that the presser foot (8) is mounted non-rotatably on the needle bar (6) in such a way that the presser foot (8) rotates with the needle bar (6) when the needle bar (6) rotates about the needle bar axis (15). sewing machine Claim 1 or 2 , characterized by a lifting drive (10) for adjusting the stroke of the presser foot (8). sewing machine Claim 3 , characterized in that the lifting drive (10) is designed as a motor actuator. sewing machine Claim 3 or 4 , characterized in that a needle bar rotating assembly (27) which can be rotated via the needle bar rotary drive (14) with the needle bar (6) and the presser foot (8) has a turntable (28), the central disk axis of which coincides with the needle bar axis (15). , wherein the lifting drive (10) is fixed to a frame of the sewing machine (1) and interacts via a connection with the needle bar rotary assembly (27) to shift the stroke. Sewing machine (1) - with a needle bar (6) for holding a sewing needle (5) for guiding an upper thread, - with a stitch plate with an opening for the sewing needle (5) to pass through during stitch formation - with a needle bar rotary drive (14) for rotating the needle bar (6) about a needle bar axis (15) running along the needle bar (6), - with a gripper assembly (17) with a gripper (7) for forming stitches that interact with the sewing needle (5) and for guiding a lower thread, - with a hook sewing drive for rotating the hook (7) about a hook axis (9), - with a gripper assembly rotary drive (16) for rotating the gripper assembly (17) about a gripper assembly axis (18) which does not coincide with the gripper axis (9). sewing machine Claim 6 , characterized in that the gripper axis (9) runs parallel to the gripper assembly axis (18). sewing machine Claim 6 or 7 , characterized in that a deflection gear (42-47) for deriving the hook sewing drive from a sewing drive motor (41) has a differential gear unit (44). Sewing machine according to one of the Claims 6 until 8th , characterized in that the needle bar rotary drive (14) and the gripper assembly rotary drive (16) are derived from one and the same rotary drive motor (13). sewing machine Claim 9 , characterized in that a deflection gear for deriving the needle bar rotary drive (14) and the gripper assembly rotary drive (16) from the rotary drive motor (13) has at least one toothed belt deflection unit (19, 21, 31).

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