STITCH FORMING TOOL MODULE FOR A SEWING INSTALLATION AS WELL AS A SEWING INSTALLATION WITH SUCH A MODULE

Abstract

A stitch-forming tool module (6) for a sewing installation is used to produce a double chain stitch (7). A sewing needle (8) of the module (6) is configured to move up and down in a driven manner in a needle stitch direction (z) perpendicular to a sewing material and to guide a sewing thread (10). A shuttle (12) of the module (6) is configured to guide a shuttle thread (18) and to oscillate in an oscillating motion plane (xz). This oscillating motion plane is defined by the needle stitch direction (z) and by a stitching direction (x) along the double chain stitch (7). A path of movement of the shuttle (12) is located, during a complete double chain stitch, entirely within the oscillating motion plane (xz).It results in a stitch forming tool module in which a shuttle drive is especially simplified.

Description

STITCH FORMING TOOL MODULE FOR A SEWING INSTALLATION AS WELL AS A SEWING INSTALLATION WITH SUCH A MODULE This patent application claims priority over German patent application DE 10 2019 219 814.7, the content of which is included in this document by reference. The invention relates to a stitch-forming tool module for a sewing machine, intended to produce a double chain stitch. The invention also relates to a sewing machine with such a module. A double chain stitch sewing machine is known from document DD-PS 1111 02. An adjustment device for the shuttle of a sewing machine is known from document DE 29 01 582 C2. Document DE-PS 104 963 discloses equipment for widening thread loops in double chain stitch machines. Document DE 3935 779 C1 discloses a shuttle ejection device in a sewing machine. Document US 6,095,069 discloses a double chain stitch sewing machine. Document DEPS 667 052 ​​discloses a sewing needle with a thread-cutting edge. It is an objective of the present invention to perfect a stitch-forming tool module of the type mentioned at the beginning, in such a way that a shuttle drive is especially simplified. This objective is achieved according to the invention by means of a group of stitch forming tools with the characteristics indicated in claim 1. According to the invention, it was found that it is not essential to provide a shuttle movement path in a double chain stitch sewing machine, where the shuttle moves perpendicularly relative to the sewing needle, yielding to an oscillating plane of movement of the shuttle. Documents DD-PS 1111 02 and DE 29 01 582 C2 disclose prior art shuttle drives that define such an elliptical movement path and are of a correspondingly complex configuration. In the module according to the invention, a correspondingly complex drive can be dispensed with. The stitching direction is located in the module according to the invention in the oscillating plane of the shuttle, which is also called an in-line system. The shuttle does not move perpendicular to the oscillating plane. The stitch-forming tool module can be configured so that it does not require an extension finger to extend a thread loop and thus facilitate threading. Such an extension finger, which is dispensed with here, is known from the obvious prior use of a Pfaff 5626 type double chain stitch sewing machine. A central longitudinal axis of the sewing needle is located at a distance from the needle point of the sewing needle. This distance between the central longitudinal axis of the sewing needle and the needle point allows for an orientation of the sewing needle with respect to the shuttle, which simplifies the unobstructed relative movement of these stitch-forming components in the stitch-forming sequence. The needle can also be made in the module according to the invention in such a way that it moves exclusively in exactly one direction, i.e., in the direction of the needle stitch, up and down, i.e., that it does not make any movement to yield to the shuttle. This is especially true for embodiments according to claims 3 or 4. A sewing installation according to claim 5 offers the advantages already explained in relation to the stitch-forming tool module. A sewing machine or an automatic sewing machine, for which the stitch-forming tool module is an integral part, may also be part of the sewing installation. A robot capable of moving a sewing head with the stitch-forming tool module in a controlled / regulated manner through several degrees of freedom may also be part of the sewing installation, so that even more complex sewing material geometries can be provided with defined stitches, especially stitches that run three-dimensionally in space.The sewing installation can therefore be a sewing robot, whose sewing head can be moved in a powered manner in several degrees of freedom of c / r;nn / zznz / B / YiAi translation or rotation, or a sewing machine. An example of an embodiment of the invention is explained in more detail below with the help of the drawing. In it, they show: Figure 1 is a very schematic side elevation of a sewing installation in the form of a sewing robot with stitch-forming components represented approximately, for producing a double chain stitch seam; Figure 2, in a view rotated 90° about a z-axis, compared to Figure 1, shows the stitch-forming components together with a sewing material support base, during the production of a test seam, in which a sewing needle carrying a sewing thread is threading into a shuttle thread loop of a shuttle; Figure 3 is a schematic view of the sewing needle and a fragment of a shuttle, seen from a visual direction III in Figure 2; and Figures 4 and 5, in representations similar to Figure 2, show two other momentary relative positions of the stitch-forming tools with respect to each other during a double chain stitch formation sequence of the test seam. Figure 1 schematically shows the main components of a sewing installation 1 implemented as a sewing robot. The sewing installation 1 has a C-shaped frame 2 with an arm 3, a base plate 4, and a frame 5 that connects the arm 3 to the base plate 4. A drive, not shown in detail, may be an integral part of sewing installation 1, allowing frame 2 to move in various degrees of translational or rotational freedom, for example, three, four, five, or six degrees of freedom. Such a drive is known in connection with industrial robots. Accordingly, sewing installation 1 may be implemented as a sewing robot. Figure 1 also shows a Cartesian xyz coordinate system to facilitate the arrangement of positional relationships. The x-axis runs perpendicular to the drawing plane of Figure 1, extending out of it. The y-axis runs to the right in Figure 1, parallel to the extension of arm 3 of base plate 4. The z-axis runs upwards in Figure 1, parallel to the extension of frame 5. The axial directions x, y, and z are also applicable to the following figures. Part of sewing installation 1 is a stitch forming tool module 6 for producing a double chain stitch seam 7, for which a pattern is represented in Figure 2 as well as in Figures 4 and 5 respectively. One stitching direction runs along the x direction, i.e., perpendicular to the yz plane predefined by the C shape in Figure 2. Module 6 has a sewing needle 8 held by a needle bar 9. The needle bar 9, and with it the sewing needle 8, can be moved in a powered manner up and down in a needle-stitch direction along the z-axis perpendicular to a sewing material not shown in the drawing. The sewing needle 8 is designed to guide a needle thread 10, also called the upper thread. For this purpose, the sewing needle 8 has an eyelet 11. It also includes a shuttle 12 which, in the side elevation according to figures 2, 4 and 5, is made in the form of a hook and is supported by an actuated shuttle holder 13. The shuttle 12 has an angled shape. A threading section 14 of the shuttle 12 has, in the area of ​​a shuttle tip 15 and at its opposite end respectively, a thread passage opening 16, 17 for a shuttle thread 18 that is also called the lower thread. The shuttle 12 is designed to guide the shuttle thread 18. Due to a drive mechanism of the shuttle holder 13 not shown in detail, the shuttle is also designed for oscillating motion in an oscillating motion plane that coincides with the xz plane, i.e., it is laid on one side by the needle stitch direction zy, and on the other side by the stitching direction xa along the double chain stitch 7. A movement path of the shuttle is located, during the complete double chain stitch, of which snapshots are shown in Figures 2, 4 and 5, entirely in the oscillating motion plane xz.Perpendicular to this oscillating xz plane of motion, shuttle 12 therefore does not perform any yielding motion. The sewing direction x is correspondingly located in the oscillating motion plane xz of the shuttle 12. Therefore, the sewing installation c / r;nn / zznz / B / YiAi constitutes an in-line system. No extension finger is included in stitch forming tool module 6. Such an extension finger, which is not present here, is known, for example, from the obvious prior use of a Pfaff 5626 chain stitch sewing machine. Figure 3 shows a schematic plan view from above of the sewing needle 8 and a section, represented in a broken way, of the threading section 14 of the shuttle 12. Especially with regard to the diameter of the sewing needle 8, the representation according to Figure 3 is enlarged. A visual direction in Figure 3 runs along a central longitudinal axis 19 of the sewing needle 8. A piercing point of a needle point 20 is also represented in Figure 3 through the drawing plane of Figure 3. From this representation, it follows that in the sewing needle 8, the central longitudinal axis 19 is located at a distance óy with respect to the needle point 20. The sewing needle 8 is therefore not rotationally symmetric in the area of ​​the needle point 20, but rather the needle point 20 is displaced by the distance óy with respect to an axis of symmetry of a base body of the needle, which coincides with the central longitudinal axis 19.With the sewing needle 8 mounted, as shown in Figure 3, the needle point 20 is located perpendicular to the oscillating plane xz at a distance óy from the central longitudinal axis 19. If, during stitch formation, the threading section 14 of the shuttle 12 passes in front of the needle point 20, the central longitudinal axis 19, as also shown in Figure 3, is located between the needle point 20 and the threading section 14 of the shuttle 12, i.e., between the needle point 20 and the shuttle 12. This offsetting of the needle point 20 facilitates the guiding of the sewing needle 8 by passing in front of the threading section 14, especially during the entry of the needle point 20, shown in Figure 2, into a loop of the shuttle thread 18. The threading section 14 is passed at a very short distance in front of a sewing needle point section 8. Basically, the two components 8, 12 can also touch during this. Figure 2 also shows a support element 21 for the sewing material and a pressure or transport foot 22 for the sewing material. During the actual sewing operation, the sewing material is moved between the support element 21 and the foot 22 in the sewing direction x. Figure 4 shows the moment in the double chain stitch formation sequence where the sewing needle 8 has reached the area of ​​a lower dead center. At the moment shown in Figure 4, the shuttle point 15 is deflected in the area of ​​a right dead center, so much so that in the projection shown in Figure 4 it has reached beyond a section 23 of the needle thread 10, guided out of the buttonhole 11.Figure 5 shows the moment in the stitch formation sequence when the threading section 14 is threaded into a loop of needle thread that has meanwhile formed in the needle thread section 23 due to the reversal of the sewing needle 8's movement. The shuttle thread 18 also passes through this loop of the needle thread section 23 in the area of ​​the thread passage opening 16 of the threading section 14. During the next needle entry (see Figure 2) of a subsequent stitch formation sequence, the sewing needle re-enters a loop of shuttle thread 18 in a negative x direction beyond this sewing thread loop. After the threading section 14 is withdrawn from the shuttle 12, the previously formed loop of needle thread section 23, intertwined with the shuttle thread 18, is thrown from the threading section 14, as can be seen. as shown in figure 4.This results in the known double chain stitch formation mechanism. Stitch 7, formed in this way, runs in the positive x-direction. Module 6 can also be prepared as a retrofit kit for a sewing installation.

Claims

1. Stitch forming tool module (6) for a sewing installation (1) for producing a double chain stitch seam (7), characterized in having a sewing needle (8) that is made so that it can move up and down in a driven manner in a needle stitch direction (z) perpendicular to a sewing material and for guiding a sewing thread (10), having a shuttle (12) that is made for guiding a shuttle thread (18) and for oscillating motion in an oscillating motion plane (xz) that is laid - by the needle stitch direction (z) and - by a stitching direction (x) along the double chain stitch seam (7), wherein a motion path of the shuttle (12) is located, during a complete double chain stitch, entirely in the oscillating motion plane (xz), - - wherein,A central longitudinal axis (19) of the sewing needle (8) is located at a distance of one needle point (20) from the sewing needle (8).

2. Stitch forming tool module according to claim 1, characterized in that the sewing needle (8) is made in such a way that it moves up and down exclusively in the needle stitch direction (z).

3. Stitch forming tool module according to claim 2, characterized in that, with the sewing needle (8) mounted, the needle point (20) is located at a distance from the central longitudinal axis (19) perpendicular to the oscillating movement plane (xz).

4. Stitch forming tool module according to claim 3, characterized in that it is made such that when, during stitch formation, the shuttle (12) passes in front of the needle point (20), the central longitudinal axis (19) is located between the needle point (20) and the shuttle (12). c / r;nn / zznz / B / YiAi 5. Sewing installation, characterized by having a stitch forming tool module according to one of claims 1 to 4.

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