TWM491682U - Thread clamping device for straight buttonhole sewing machine - Google Patents

Description

Wire gripper for flat head keyhole sewing machine New field

The present invention relates to a wire gripper for a flat keyhole sewing machine (Wäscheknopfloch-Nähmaschine) and a flat keyhole sewing machine with such a wire gripper.

New background

A wire gripper for a sewing machine is known, for example, from DE-PS 607 034, DE-PS 1 063 017, DE 39 11 134 A1 and EP 2 589 694 A1.

New summary

The object of the present invention is to improve the gripper for a flat-headed sewing machine so that a larger underfeed can be placed in the bobbin.

According to the novel, this task is solved by a gripper having the features described in claim 1.

It has been recognized in accordance with the present invention that it is possible to significantly increase the hull of the wire gripper for a flat-bottom button sewing machine in terms of its axial extension relative to known wire grippers. This is possible, although this is in the flat buttonhole sewing machine In the case of miscellaneous stitching, the line guidance for correct line tying becomes significantly more troublesome. The increased axial extension of the coil housing according to the present invention, which can be used to position the coils, enables the placement of larger volume coils, ie larger spools or larger bobbins. The coil housing can be embodied as a bobbin case or as a bobbin case. The axial extent of the coil shell that can be used to seat the coil can be, for example, 11 mm, 12 mm, 13 mm, 14 mm or 15 mm, or can be larger. The gripper can be embodied as a horizontal gripper, ie as a gripper that rotates about a horizontal axis.

The embodiment according to claim 2 avoids the situation in which the mechanical components of the sewing machine cooperating with the gripper need to be converted or reconstructed when using the gripper according to the invention. In particular, the thread take-up drive of the sewing machine can be kept structurally unchanged.

According to the claim 3, the axial distance of the free end of the gripper tip to the upper side of the gripper cover enables an arrangement of the gripper according to the present invention such that the free end of the gripper tip is axially The position is aligned with the axial position of the standard gripper, which is used in place of the gripper according to the present invention. Surprisingly, it is possible to ensure that the needle thread is free from the tip end of the gripper during the sewing operation at such a large axial distance from the free end of the gripper tip to the upper side of the gripper cover. Reliable operation through the upper side of the gripper cover. The axial distance from the free end of the gripper tip to the upper side of the gripper cover may be, for example, 13 mm or may be at least 15 mm or more.

The axial arrangement of the free end of the gripper tip according to claim 4 between the upper side of the gripper cover and the bottom of the bobbin case enables Increase the volume in the gripper for the bobbin case.

The advantages of the flat-headed sewing machine according to claim 5 correspond to the advantages already explained with reference to the wire gripper according to the present invention.

1‧‧‧ sewing machine

2‧‧‧Substrate

3‧‧‧ stand

4‧‧‧Bent arm

5‧‧‧ head

6‧‧‧Bear axis

7‧‧‧ crank drive

8‧‧‧Thread take-up

9‧‧‧ Needle bar

10‧‧‧Sewing needle

12‧‧‧ spool

13‧‧‧ Needle thread

16‧‧‧support plate

17‧‧‧Sewing parts

20‧‧‧ stitch holes

21‧‧‧Clamping device

22‧‧‧Clamping shell

23‧‧‧Clamp tip

24‧‧‧Rotation axis

25‧‧‧Support block

26‧‧‧ drive shaft

27‧‧‧Belt transmission

28‧‧‧Clock shell

29‧‧‧The upper part of the coil

30‧‧ hood

31‧‧‧ Grab the parts

32‧‧‧The lower part of the coil

33‧‧‧Free end; leading end

34‧‧‧Upper side

35‧‧‧ bottom

A‧‧‧ axial extension

B, C‧‧‧ axial distance

The embodiments of the present invention are explained below with the aid of the drawings. Wherein: Figure 1 shows a front view of a portion of the sewing machine with a horizontal gripper that exposes internal details; Figure 2 shows a perspective view of the horizontal gripper of the sewing machine according to Figure 1; Figure 3 shows Side view of the horizontal gripper (the gripper axis is parallel to the plane of the drawing); FIG. 4 shows a perspective view of the lower portion of the bobbin case of the gripper according to Fig. 2; Fig. 5 is shown in a similar view to Fig. 3. 4 is a side view of the lower portion of the bobbin case according to FIG. 4; FIG. 6 shows a perspective view of the gripper housing of the horizontal gripper according to FIG. 2; FIG. 7 is shown in a side view similar to FIGS. 3 and 5. The gripper housing according to Fig. 6; and Fig. 8 shows the axial longitudinal section through the horizontal gripper according to Figs. 2 and 3.

Detailed description of the preferred embodiment

A sewing machine 1 implemented as a flat buttonhole sewing machine has a substrate 2, which The substrate has a stand 3 and a curved arm 4 extending upward from the substrate. The end of the curved arm 4 is the head 5. The arm shaft 6 is rotatably mounted in an arm 4 which drives a crank drive 7 with a thread take-up lever 8 in the head 5. The crank drive 7 is connected in a driving manner to a needle bar 9 which is displaceably arranged in the head 5 . The needle bar has a sewing needle 10 on its lower end. The sewing needle 10 can be moved up and down by the crank drive unit 7. Here, the sewing needle 10 passes through the movement space. The sewing needle 10 guides the needle thread 13 in its eyelet, which is delivered from the spool 12 through the threading device and the thread take-up lever 8.

A support plate 16 is mounted on the substrate 2, and the sewing material portion 17 is placed on the support plate. The support plate 16 has a stitch hole 20 through which the sewing needle 10 passes.

Below the support plate 16, a gripper 21 is arranged, which has a gripper housing 22 with a gripper tip 23 on the outer casing side. The gripper tip 23 is used to grip the needle coil as is known from the prior art. The gripper 21 is generally illustrated in Figures 2 and 3, while the gripper housing 22 is generally illustrated in Figures 6 and 7. The gripper 21 is a horizontal gripper and thus has a horizontal axis of rotation 24 which runs parallel to the bearing plane of the support plate 16. The axis of rotation 24 is also referred to as the gripper axis.

The gripper housing 22 is connected to the shaft in a rotationally fixed manner, which shaft runs coaxially to the axis of rotation 24 . The shaft is rotatably disposed in a support block 25 that is screwed to the substrate 2. Also mounted in the support block is a drive shaft 26 that is coupled to a gear drive disposed within the support block 25. The drive shaft 26 is drivingly coupled to the arm shaft 6 via a belt drive 27.

The gripper 21 includes a bottom thread supply. The bottom thread of the bottom thread is sewn together with the needle thread 13 in the sewing material 17, for example for forming a flat keyhole.

The bottom line is placed in the gripper 21 as a coil. According to an embodiment, the coil is embodied as a bobbin or a bobbin.

The coils are placed in the bobbin 28 of the line. The bobbin case 28 is inserted into the gripper housing 22 in a rotationally fixed manner. The bobbin case 28 has a bobbin case upper portion 29 with a cover 30 and a foldable, cover side gripping member 31 for gripping the bobbin case 28. Furthermore, the coil housing 28 has a coil housing lower portion 32, which is shown separately in Figures 4 and 5. Figures 4 and 5 show the lower portion of the coil housing implemented as the lower portion of the bobbin case.

The lower portion 32 of the bobbin and thus the entire bobbin 28 has an axial extension A that can be used to position the bobbin, which is greater than 10 mm. This axial extension A is also shown in FIG. In the embodiment shown, the axial extension A that can be used to place the coils is 13 mm. According to an embodiment of the coil housing 28, other examples of axial extension A are 11 mm or 12 mm. An axial extension A greater than 13 mm, such as 14 mm or 15 mm, is also possible. A larger axial extension A is also possible.

The axial distance B of the free end 33 of the gripper tip 23 from the upper side 34 of the cover 30 is greater than 10 mm and is approximately 13 mm in the embodiment shown. This axial distance B is also shown in FIG. Depending on the embodiment of the thread gripper 21, the axial distance B can also be, for example, 11 mm or 12 mm. A larger axial distance B is also possible, for example an axial distance B with an axial distance B of 14 mm, 15 mm or more.

In the axial direction with respect to the gripper axis 24, the bottom 35 of the lower portion 32 of the bobbin case is located on the other side of the axial position of the upper side 34 of the shroud with respect to the axial height of the free end 33 of the gripper tip 23. Self-winding tip 23 The axial distance C from the end 33 from the bottom 35 is approximately 1.5 mm in the embodiment shown. The axial distance C on the side of the free end 33 of the gripper tip 23 opposite the upper side 34 is greater than 0 mm, and can be used, for example, in other embodiments of the gripper 21 , in accordance with an embodiment of the gripper 21 . It is 0.5 mm, 1.0 mm, 2.0 mm, 2.5 mm, 3.0 mm, 4.0 mm, 5.0 mm or may be larger.

In summary, the gripper 21 is embodied such that in the case of the installed gripper 21, the free end 33 of the gripper tip 23 is along the axial position of the gripper axis 24 with a standard gripper (ie line The axial position of the free end of the gripper tip of the gripper of the envelope 28 having an axial extension A of less than 10 mm is uniform.

The gripper tip 23 is embodied such that during the creation of the seam, the needle thread 13 overcomes the gap between the free end 33 of the gripper tip 23 and the upper side 34 in the case of forming a loop to tie the needle thread 13 to the underline. The entire axial distance B. This is also known as axial climbing (axiales Klettern). Accordingly, the axial distance B is also referred to as a line climbing stroke.

21‧‧‧Clamping device

22‧‧‧Clamping shell

24‧‧‧Rotation axis

28‧‧‧Clock shell

32‧‧‧The lower part of the coil

34‧‧‧Upper side

35‧‧‧ bottom

A‧‧‧ axial extension

B, C‧‧‧ axial distance

Claims (5)

A wire gripper for a flat-head keyhole sewing machine, comprising: a wire gripper shell with a gripper tip for gripping a needle coil, a coil bobbin for accommodating a coil, Characterized in that the coil shell has an axial extent greater than 10 mm that can be used to position the coil along the gripper axis. A wire gripper according to claim 1, characterized in that, in the case of the installed wire gripper, the axial position of the leading end of the gripper tip along the gripper axis is replaced with an alternative The standard clamps have the same axial position. A wire gripper according to claim 1, characterized in that the axial distance of the free end of the gripper tip from the upper side of the gripper cover is greater than 10 mm. A wire gripper according to claim 1, wherein the free end of the gripper tip has an axial distance from the bottom of the gripper cover of more than 0.5 mm, wherein the free end of the gripper tip is about the gripping line The axial position of the axis is between the upper side of the gripper cover and the bottom of the bobbin case. A flat head keyhole sewing machine having the wire gripper according to claim 1.