DE102019103847A1 - sewing machine - Google Patents

Abstract

The invention relates to a sewing machine, comprising a support surface (1) for sewing material to be sewn together with the upper and lower thread and lying on the support surface (1), with a bobbin (2) below, on the side of the support surface (1) facing away from the sewing material is arranged by bobbin thread. According to the invention it is provided that underneath the support surface (1) there is arranged a lower thread preparation device (3) which cooperates with the lower thread bobbin (2), provides a predetermined length of lower thread and operates independently of the upper thread.

Description

The invention relates to a sewing machine according to the preamble of claim 1.

A sewing machine of the type mentioned is from the document DE 31 12 032 A1 known. This consists of a support surface (called "cover plate" there) for sewing material to be sewn together with the upper and lower thread and lying on the support surface, with a bobbin (called "bobbin" there) for receiving the bobbin thread below, on the side of the support surface facing away from the sewing material is arranged. In this sewing machine, thread can be fed to the bobbin without having to take it out with the aid of the needle located above the support surface, so-called upper thread.

The invention is based on the object of improving a sewing machine of the type mentioned above. In particular, a sewing machine that can be equipped with bobbin thread particularly well and easily is to be created, in particular with a bobbin thread that does not correspond to the upper thread.

This object is achieved with a sewing machine of the type mentioned at the beginning by the features listed in the characterizing part of patent claim 1.

According to the invention it is therefore provided that a lower thread preparation device which interacts with the lower thread bobbin, provides a predetermined length of lower thread and operates independently of the upper thread is arranged below the support surface.

In other words, the solution according to the invention is characterized in that the lower thread bobbin is assigned a bobbin thread supply device specially provided for this purpose in order to be able to equip the bobbin with a predetermined length of bobbin thread if necessary. This requirement is particularly advantageous in sewing processes (because it increases process reliability) in which the bobbin is to be equipped with exactly the length of bobbin thread that is required for the next seam, which is particularly advantageous in industrial sewing production, since the length the following seam is usually known.

If, as usual, a needle drive is available for sewing the upper thread, a separate bobbin drive that operates independently of the needle drive is particularly preferably provided for driving the lower thread bobbin. This is able to turn the bobbin even when the needle drive is at a standstill.

Other advantageous developments of the sewing machine according to the invention emerge from the dependent claims.

• Aus dem Dokument DE 1 485 273 C ist eine Nähmaschine bekannt, bei der zwei Unterfadenspulen vorgesehen sind.

For the sake of completeness, reference is made to the following prior art, which is further removed:

• From the document DE 1 485 273 C a sewing machine is known in which two bobbins are provided.

From the document DE 16 60 989 C3 Another sewing machine is known in which the bobbin can be filled via the needle thread.

From the document DE 195 08 927 A1 a sewing machine with a bobbin housing is known to which cartridges filled with bobbin thread can be fed when required.

From the document DE 196 21 430 A1 a sewing machine with a rotating unit for two bobbins is known.

From the document DE 10 2016 005 166 A1 a sewing machine with several, revolver-like mounted bobbins is known.

The sewing machine according to the invention including its advantageous developments according to the dependent claims is explained in more detail below with reference to the drawing of two exemplary embodiments.

• 1 in Draufsicht einen Teil der Nähmaschine in einer ersten Ausführungsform mit der erfindungsgemäßen Unterfadenbereitstellungseinrichtung (ohne Unterfaden);
• 2 im Vertikalschnitt die Unterfadenspule gemäß 1 mit Turbinenantrieb;
• 3 im Horizontalschnitt die Unterfadenspule gemäß 1;
• 4 in Draufsicht einen Teil der Nähmaschinen in Unterfadenzuführ- und aufwickelposition;
• 5 im Vertikalschnitt die Unterfadenspule gemäß 4 bei seitlich eingeführtem Fadengeberröhrchen;
• 6 in Draufsicht einen Teil der Nähmaschine nach Vollendung des Aufwickelns und Abschneidens des Unterfadens;
• 7 perspektivisch eine zweite Ausführungsform mit einem elektromagnetischen Antrieb der Unterfadenspule; und
• 8 im Schnitt die Unterfadenspule mit elektromagnetischem Antrieb gemäß 7.

It shows

• 1 a plan view of a part of the sewing machine in a first embodiment with the lower thread supply device according to the invention (without lower thread);
• 2 in vertical section the bobbin according to 1 with turbine drive;
• 3 in the horizontal section the bobbin according to 1 ;
• 4th a plan view of a part of the sewing machine in the lower thread feed and winding position;
• 5 in vertical section the bobbin according to 4th with the thread feeder tube inserted at the side;
• 6th a plan view of a part of the sewing machine after completion of winding and cutting of the bobbin thread;
• 7th a perspective view of a second embodiment with an electromagnetic drive for the lower thread bobbin; and
• 8th in section the bobbin with electromagnetic drive according to 7th .

The sewing machine according to the invention, partially shown in the figures, initially consists in a known manner of a support surface 1 for things to be sewn together with upper and lower thread on the contact surface 1 overlying sewing material, below, on the side of the support surface facing away from the sewing material 1 a bobbin 2 is arranged for receiving bobbin thread. For sewing the upper thread, a needle drive (not shown separately) is also provided in a manner known per se.

It is now essential for the sewing machine according to the invention, and this applies to all embodiments, that below the support surface 1 one with the bobbin 2 cooperating, a predetermined length of bobbin thread providing and working independently of the upper thread bobbin thread supply device 3 is arranged.

It is also preferred in all embodiments that the support surface 1 is designed to run horizontally.

It is also preferred in all embodiments that the lower thread supply device 3 a thread donor tube 4th comprises, preferably the thread donor tube 4th between a rest position and a thread insertion position about an axis of rotation 4.1 is pivoted (see 1 ). The axis of rotation is then preferably 4.1 perpendicular to the support surface 1 oriented running. It is also preferred that the thread feeder tube 4th has a free inner diameter that matches the diameter of the lower thread and / or that on the thread feeder tube 4th one a slipping out of the lower thread from the thread take-up tube 4th preventing clamping device is provided.

In addition, it is preferred in all embodiments that the lower thread bobbin 2 an upper and a lower clamping disc 2.1 , 2.2 comprises, preferably a free end of the thread donor tube 4th in thread insertion position to pinch the lower thread between the two clamping discs 2.1 , 2.2 is positioned (see 4th and 5 ). The two clamping disks are also preferred 2.1 , 2.2 between them a space 2.3 designed to hold the lower thread in a limiting manner (see 2 ). In addition, there is preferably a distance between the support surface 1 and the upper clamp washer 2.1 invariable and a distance between the support surface 1 and the lower clamp washer 2.2 designed to be variable, it is also preferred that a spring element 5 , especially one (in 2 only schematically shown) helical compression spring, for pressing the two clamping disks against one another 2.1 , 2.2 is provided.

In addition, it is preferred in all embodiments that the bobbin 2 rotatable in a capsule 10 is stored (see 5 ) and / or that preferably for the rotatable mounting of the lower thread bobbin 2 a ball bearing 8th , in particular a deep groove ball bearing is provided. It is also preferred that an axis of rotation 2.4 the bobbin 2 perpendicular to the support surface 1 is designed to run oriented. It is preferably used to drive the bobbin 2 a bobbin drive that works independently of the needle drive 6th intended.

In the first embodiment according to 1 to 6th is a turbine wheel that can be charged with compressed air 6th provided (see in particular 3 ). It is also preferred that the lower thread bobbin 2 and the turbine wheel 6th a common axis of rotation 2.4 have, preferably the turbine wheel 6th torsion-proof with the upper clamping disc 2.1 connected is formed.

In the second embodiment according to 7th and 8th it is provided that the rotatable bobbin 2 Is formed electromagnetically driven. This is done with several magnets 2.5 provided trained. In addition, it is preferably provided that the magnet 2.5 several with the magnets 2.5 cooperating electrical coils 2.6 , which are stationary to the support surface 1 are arranged, are assigned. Considered even more precisely, it is also particularly preferably provided that the magnets 2.5 on the upper clamping disc 2.1 and the electric coils 2.6 between the magnets 2.5 and the support surface 1 are arranged. Furthermore, it is preferably provided that the magnets 2.5 and the electric coils 2.6 are arranged along a circular line. How to continue in particular 8th can be seen is between the magnets 2.5 and the electric coils 2.6 an air gap is provided.

Furthermore, and this again applies to all embodiments, it is preferred that in the support surface 1 both a passage opening for a needle with the upper thread and a material transport device are provided. It is also preferred that below the support surface 1 a bobbin thread cutter 7th for cutting the bobbin thread after filling the bobbin 2 is arranged with bobbin thread. Preferably the bobbin thread cutter 7th from two string knives 7.1 , 7.2 is formed (see 6th ). It can also be provided that below the support surface 1 a thread cutter 9 is arranged for the common cutting of the upper and lower thread.

• Zwischen zwei Nähvorgängen, während die nähende Person damit beschäftigt ist, das nächste Nähgut an der Nähmaschine anzuordnen, wird möglichst genau so viel Faden auf die Unterfadenspule 2 aufgespult, wie zum Nähen des nächsten Nähguts benötigt wird. Dabei befindet sich die Nähmaschine zunächst in der Stellung gemäß 1. Der aufzuspulende Unterfaden, der von einer neben oder an der Nähmaschine angeordneten Fadenreserve stammt, ist im Fadengeberröhrchen 4 angeordnet und ragt mit seinem freien Ende über dieses hinaus. Der Unterfaden ist dabei, wie bereits erwähnt, mittels einer Klemmvorrichtung gegen Herausrutschen aus dem Fadengeberröhrchen 4 gesichert. Das Fadengeberröhrchen 4 ist zunächst von der Unterfadenspule 2 beabstandet angeordnet, wird dann aber durch Drehung um seine Drehachse 4.1 zur Unterfadenspule 2 hin gedreht bis es sich zwischen die obere und die untere Klemmscheibe (2.1, 2.2) schiebt, welche dadurch leicht voneinander separiert werden und den Raum 2.3 vergrößern. Diese Position ist in 4 dargestellt. Wird nun das Fadengeberröhrchen 4 wieder aus der Unterfadenspule 2 heraus gedreht, so werden die obere und die untere Klemmscheibe (2.1, 2.2) unter Einfluss des Federelements 5 wieder zusammengepresst und klemmen dabei das freie Ende des Unterfadens zwischen sich ein.

The sewing machine according to the invention works as follows:

• Between two sewing processes, while the sewing person is busy arranging the next sewing material on the sewing machine, as much thread as possible is placed on the bobbin 2 wound up as needed to sew the next material. The sewing machine is initially in the position according to 1 . The bobbin thread to be wound up, which comes from a thread reserve arranged next to or on the sewing machine, is in the thread take-up tube 4th arranged and protrudes with its free end beyond this. As already mentioned, the lower thread is prevented from slipping out of the thread feeder tube by means of a clamping device 4th secured. The thread feeder tube 4th is first from the bobbin 2 spaced apart, but is then rotated about its axis of rotation 4.1 to the bobbin 2 turned until it is between the upper and lower clamping disc ( 2.1 , 2.2 ) pushes, which are thereby easily separated from each other and the room 2.3 enlarge. This position is in 4th shown. Will now be the thread feeder tube 4th again from the bobbin 2 unscrewed, the upper and lower clamping washers ( 2.1 , 2.2 ) under the influence of the spring element 5 pressed together again, pinching the free end of the lower thread between them.

Now the spool drive will be 6th , so either the turbine wheel 6th or the electromagnetic drive made of magnets 2.5 and coils 2.6 activated, the bobbin begins 2 to turn. This places the bobbin thread on the bobbin 2 wound up. The coil drive 6th is switched off again when there is enough bobbin thread for the next planned seam on the bobbin 2 is located. To determine or calculate the required amount of thread and the associated drive time of the bobbin 2 an electrical or electronic control system (consisting of appropriate hardware and software) is preferably used here.

After the bobbin 2 so the bobbin thread is wound up using the bobbin thread cutter 7th between the bobbin 2 and the thread feeder tube 4th cut off. The next sewing process can now begin. It should be noted here that after the sewing process there may still be small remnants of the bobbin thread that have not been sewn, as there are always certain tolerances when winding the bobbin 2 must be observed. After sewing, these remnants are either pulled out with the material or with the thread cutter before the material is removed 9 cut off and sucked off with compressed air.

List of reference symbols

1

Support surface

2

Bobbin

2.1

upper clamp washer

2.2

lower clamp washer

2.3

room

2.4

Axis of rotation

2.5

magnet

2.6

electric coil

3

Bobbin thread supply device

4th

Thread feeder tube

4.1

Axis of rotation

5

Spring element

6th

Coil drive

7th

Bobbin thread cutter

7.1

Line knife

7.2

Line knife

8th

ball-bearing

9

Thread cutter

10

capsule

QUOTES INCLUDED IN THE DESCRIPTION

This list of the 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.

Patent literature cited

• DE 3112032 A1 [0002]
• DE 1485273 C [0009]
• DE 1660989 C3 [0010]
• DE 19508927 A1 [0011]
• DE 19621430 A1 [0012]
• DE 102016005166 A1 [0013]

Claims (10)

Sewing machine, comprising a support surface (1) for sewing material to be sewn together with the upper and lower thread and lying on the support surface (1), a bobbin (2) for receiving the bobbin thread being arranged below on the side of the support surface (1) facing away from the sewing material , characterized in that underneath the support surface (1) there is arranged a lower thread preparation device (3) which cooperates with the lower thread bobbin (2), provides a predetermined length of lower thread and operates independently of the upper thread. Sewing machine after Claim 1 , characterized in that the lower thread supply device (3) comprises a thread take-up tube (4). Sewing machine after Claim 2 , characterized in that the thread feeder tube (4) is mounted pivotably about an axis of rotation (4.1) between a rest position and a thread insertion position. Sewing machine after Claim 2 or 3 , characterized in that a clamping device preventing the lower thread from slipping out of the thread feeder tube (4) is provided on the thread feeder tube (4). Sewing machine according to one of the Claims 1 to 4th , characterized in that the lower thread bobbin (2) comprises an upper and a lower clamping disc (2.1, 2.2). Sewing machine after Claim 2 and 5 , characterized in that a free end of the thread feeder tube (4) is positioned in the thread insertion position for clamping the lower thread between the two clamping disks (2.1, 2.2). Sewing machine after Claim 5 or 6th , characterized in that the two clamping disks (2.1, 2.2) are designed to delimit a space (2.3) between them for receiving the lower thread. Sewing machine according to one of the Claims 5 to 7th , characterized in that a spring element (5) is provided for pressing the two clamping disks (2.1, 2.2) against one another. Sewing machine according to one of the Claims 1 to 8th , a needle drive being provided for sewing the upper thread, characterized in that a bobbin drive (6) which operates independently of the needle drive is provided for driving the lower thread bobbin (2). Sewing machine according to one of the Claims 1 to 9 , characterized in that a bobbin thread cutter (7) for cutting the bobbin thread after filling the bobbin (2) with bobbin thread is arranged below the support surface (1).

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