CH658271A5 - SEWING MACHINE. - Google Patents

Description

The present invention relates to a sewing machine - web grippers rotating in a horizontal plane are machines with an oscillating motion in a vertical plane;

Web gripper according to the preamble of claim 1. the web grippers so different that one use

Sewing machines with oscillating web grippers are well known, as is the case with the separating bracket proposed there. Oscillating web hooks (CB hooks) have the advantage of the present invention over other hook systems that they create a means by which the formation of loose upper thread around the hook and the bobbin case Stitches are not twisted during the slow sewing of zigzag stitches in the sewing loop, and that the free thread-through machine with oscillating tread in a vertical plane between the hook and driver finger can be prevented by the reversing end of the web gripper.

movement of the driver and gripper without special aids. 55 Another object of the invention is that it is secured. Such grippers are therefore generally very means to be designed such that they are not insensitive to thread tension and result in a stitch quality.

nice and even seam. Another object of the invention is that

As with other gripper systems, the CB agent also has to be designed in such a way that there is no interference with the existing grippers and there is no mutual friction between the various mechanics, as well as easy and inexpensive to produce thread legs, the strength of which depends on the len.

Sewing conditions (stitch type, stitch length, stitch width, thread loading- According to the invention, these tasks are solved according to the nature, sewing speed, etc.), different characterizing features of claim 1 can be solved and can adversely affect certain advantageous embodiments. Further advantageous embodiments are in the dependent Sewing result affects. 65 described claims.

As is well known, the upper thread loop in CB grippers is the means for briefly braking the rear sight

Completely around the looper body and the bobbin case with the lower thread loop are preferably designed so that the bobbin thread contained therein is guided around and without mechanical intervention in the existing looper system.

3rd

658 271

stem can be inserted and can interact with existing elements. In particular, it is advantageous to include the gripper back as a braking surface. The thread is preferably braked near the web rib, with a spring wire or another element resiliently yielding on the back of the looper, e.g. a brush-like structure, a loop made of flexible material, which can also be part of the driver body, is provided.

If the braking element consists of a spring wire, this is preferably provided with a ramp-like inlet section for the thread leg and imposed on the driver body through two bores in the latter. A circumferential recess on the driver plate also fixes the wire in the locked position.

The invention is described in more detail using an illustrated embodiment. Show it:

FIG. 1 shows a driver body with a wire brake from the front (on the bobbin case side),

FIG. 2 shows a driver body with a brush-like brake from the front,

FIG. 3 shows a partial cross section of the driver body according to FIG. 1 with the web gripper and bobbin case inserted,

Figure 4 shows the stitch formation area of a sewing machine and

Figure 5 is a sewing material in section with two "loose" stitches. In Figures 1 and 2, a driver body 1 is omitted with all parts that are not essential to the invention, e.g. the damper spring, shown in perspective. The driver part 3 is placed on the plate-shaped part 2 as an arc segment. In the center, the fastening screw 4 for connecting the part 2 to a drive shaft 5 can be seen. In the edge 6, which slopes slightly conically towards the center of the part 2, two bores 7 and 8 which are substantially parallel to the shaft 5 are made in FIG. The first bore 7 preferably has a funnel-shaped opening 9. A spring wire 10 of ramp-like shape penetrates the two bores 7 and 8 in such a way that the wire 10 in the second bore 8 is parallel to the bore axis and is guided in an axially freely movable manner therein. The angled end 11 of the wire 10 prevents it from sliding out of the bore 8. The hole 7 penetrates the wire diagonally, i.e. it bears against the edges forming the openings of the bore 7 and is immovably held by it in the axial direction. The end 12 of the wire 10 running on the back of the part 2 can be embedded in a recess 13 (FIG. 3) attached to the part 2 or connected to the part 2 by other suitable fastening means (not shown).

Instead of the wire bent up like a ramp over the edge 6, one with the edge 6 can of course also be used

stepped or welded steel or plastic tab or loop.

In Figure 2, a brush-like cushion 14 is glued on instead of the ramp-like wire 10. The bristles 15 of the 5 cushion 14 can end openly or can be designed as loops. The open ends of the bristles 15 are preferably rounded in order not to damage the thread to be braked.

The partial cross section according to FIG. 3 shows the drive body 1 with the web gripper 16 and the bobbin case 17 with the io bobbin 18 and the yarn supply 19 contained thereon. The spring wire 10 lies with the highest part of the ramp-like section near the so-called, the peripheral end of the Gripper 16 forming web rib 20 on the gripper back 21. The contact force of the spring wire 10 on the Greils ferridge 21 is preferably 10 to 15 p. The position of the wire end 12 in the recess 13 is indicated. When a cushion 14 is used, the ends of the bristles 15 analogously come into contact with the gripper back 21.

The mode of operation of the present invention is explained on the basis of the illustration shown in FIG. 4 of the most important parts of a sewing machine participating in stitch formation: in the position shown, the needle 22 is in the upper reversal point. The upper thread 23, also called the needle thread 25, or the upper thread loop, consisting of a front leg 24, which runs through the needle eye 25 to the thread layer 26, and a rear leg 27, which ends in the sewing material (not shown in FIG. 4) already guided around the looper body 28 and the bobbin case 17, thrown off by 30 and is pulled up by the thread layer 26. A lower thread 29 lies between the two legs 24 and 27, the front leg 24 of the upper thread 23 abutting the lower thread 29. So that the rear leg 27 cannot be pulled up faster than the front leg 24 due to the mutual friction of the lower thread 29 and the front leg 24 35 of the upper thread 23, the rear leg 27 is between the hook back 21 and the spring 10 or the brush 14 passed and gently braked. As soon as the upper thread loop, consisting of the 40 legs 24 and 27, is pulled up so far that its apex is in the braking area on the hook back 21, it can slide out of the braking area and be drawn evenly into the material.

FIG. 5 shows the effects of rear legs 27 of the upper thread 23 being pulled up too quickly on the stitches A. The stitches A are not completely drawn into the sewing material 30 like the stitches B, but protrude from it as loops. As described in the introduction, these loose loops generally only appear when the transition is made from the right-hand stitch to the left-hand stitch, viewed in the direction of transport T of the sewing material.

C.

2 sheets of drawings

Claims (10)

658 271 2 PATENT CLAIMS dropped shortly before the gripper reversal point. The 1. The sewing machine with an oszil loop in a vertical plane is now fed into the sewing material by the thread lever and a bobbin gene stored in the hook. The front thread leg of the capsule with thread supply is primarily characterized in that on the loop, which leads to the needle, pulled up, while looper driver (1) a means (10, 14) for braking the rear leg of the thread leg behind the looper almost ren leg (27) of the upper thread loop behaves passively when retracting the. The lower thread leading from the bobbin case to the underside of the loop into the sewing material (30) through the thread layer (26) runs between the two threads. Thread thighs and hinders the thread 2. Sewing machine according to claim 1, characterized in not. If the stitch length and width are large, the needle sticks so that the means for braking consist of a spring wire (10) attached to the driver (1) i0 during the transition from the right-hand stitch to the left-hand stitch. the underside running between the bobbin case and the material 3. Sewing machine according to claim 2, characterized marked. The upper thread loops after the wetting that the spring wire (10) rises like a ramp from throwing the loop through the looper around the lower thread opposite the looper back (21) to the edge (6) of the, which results in additional thread friction on the front Fa driver (1) protrudes. 15 thigh of the upper thread loop caused. This will 4. Sewing machine according to claim 2, characterized in that the rear leg of the upper thread is pulled up faster, net that in the edge (6) of the driver (1) a first hole (7). At medium to high sewing speed, this and a second hole ( 8) are provided, the ram circumstance not out, because the stitch formation process takes place very quickly, the middle part of the spring wire (10) rising like a pen and the rear leg of the thread is too sluggish to penetrate diagonally onto the bore (7) and clamped in it 20 is additional friction of the front leg on the lower thread, and that the end closing the ramp-like part to respond. If the sewing speed is low, the fades of spring wire (10) rub against each other longer and more slowly in the second bore (8), whereby the adhesive is guided, the angled end (11) having more of an effect on the suspension component than the sliding friction wire (10 ) sliding out of the second hole (8) component. The rear thread leg prevents the upper thread. 2s loop is pulled up too quickly, which results in 5. Sewing machine according to claim 4, characterized in that the thread is not completely drawn into the material to be sewn, that the second end (12) of the spring wire (10) is in one gene and creates a “loose stitch”. Loose stitches of this type on the back of the driver (1), the puncture (13) usually occur very irregularly and impair the fact that it is embedded. good appearance of the seam. 6. Sewing machine according to claim 1, characterized. In other gripper systems an attempt was made to simulate that the means for braking from a driver (1) influence of this friction by suitable means on a fixed, bristle (15) cushion ( 14) exists. to reduce the acceptable level. 7. Sewing machine according to claim 6, characterized in DE-GM 7 016 286 is a sewing machine with umlau-net that the bristles (15) are loop-like. described gripper. The needle thread loop is - 8. Sewing machine according to claim 1, characterized in that after it has detached itself from the rotating hook - by net that the means (10, 14) rest against the hook back (21). a horn-shaped arm and one adjacent to it 9. Sewing machine according to claim 8, characterized marked holding fingers, on the one hand to prevent mutual friction, net that the means (10, 14) in the vicinity of the web rib (20) or contact of the threads and on the other hand egg-on the hook back (21). counteracting the uneven dissolution of the loop 10. Sewing machine according to claim 2, characterized marked 40 ken. This measure fulfills the demands placed on them that the spring wire (10) with a force of 10 ~ 2 to gen with rotating web grippers. A transmission of the same 1,5,10 ~ 2N presses against the back of the gripper (21). It is not possible to use oscillating web grabs. From US Pat. No. 4,095,539, a further direction to avoid mutual friction of the two 45 known the leg of the needle thread loop. Because of the