DE8414515U1 - BOBBIN HOUSING TOP OF A DOUBLE-LOCKED GRIPPER - Google Patents

Description

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G / N / 022 / DE Upper part of the bobbin case of a lockstitch looper s

The innovation relates to a bobbin case upper part according to the Preamble of claim 1.

It is a lockstitch looper with a bobbin case upper part according to the preamble of claim known (DE-OS 24 33 797), in which the disc coil inserted into the coil housing upper part with a finger-like braking member cooperates, the aun an effective, resting on the edge of the disc coil position, under the Effect of the bobbin thread running under tension can be brought into an ineffective position that does not brake the disc bobbin. In which known lockstitch looper is immediately after interruption or completion of a sewing process - so if no bobbin thread from said disc reel is withdrawn - undesired further rotation of the disc reel due to its inertia is thereby avoided, that the brake finger wrapped around by the bobbin thread, now no longer influenced by the thread withdrawal, is instantly at the edge of the disc bobbin applies braking. However, this brake finger does not allow the so-called corner sewing, which is known to be one of two sewing needles switched off briefly and nevertheless a corresponding amount of thread is drawn off the disc bobbin with each sewing material transport step, the withdrawn amount of bobbin thread that is currently not required for stitch formation is retained in a controlled manner.

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The innovation specified in claim 1 is based on the task to equip a bobbin case upper part with a pivotable thread eyelet, which counteracts the action during its pivoting movement a spring is guided concentrically to the center of rotation of the lockstitch looper and positively, the spring being independent of the Thread eyelet is dimensionable.

With the upper part of the bobbin case with said thread eyelet - if the sewing machine in question has a known thread cutter is equipped - prevents the thread eyelet from being displaced from the center of rotation of the lockstitch looper due to forces occurring during thread catching and cutting off and with this collided. On the other hand, the concentrically guided thread eyelet prevents it from colliding with the leaf spring arranged on the circumference of the upper part of the bobbin case for generating the lower thread tension prevented. Finally, the independent dimensioning of the thread eyelet and the spring acting on it make it possible more favorable thread deflection ratios and coordination of the retraction force of the lower thread with the clamping force of the thread catcher.

Appropriate developments of the object according to claim 1 are in the subclaims described. In the embodiment according to claim, the thread eyelet and the annular section are that of the groove of the approach located on the bobbin case upper part is received, made in one piece from spring wire.

An exemplary embodiment of the innovation is illustrated with reference to FIGS. 1 to 4 explained. In Fig. 5, a further embodiment according to claim 3 is shown.

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It shows:

1 shows a perspective view of the upper part of the bobbin case

without disc reel Fig. 2 is a perspective view of the upper part of the reel housing

with disc coil Fig. 3 is a sectional view along the section line AB through a lockstitch looper with vertically arranged

Looper drive shaft Fig. 4 is a view of the rear side of the thread eyelet carrying

Washer that, when installed, faces the flat inside of the

Spool housing upper part is directed to Fig. 5 is a view of a made only from spring wire

Thread eyelet with a circular section according to

Claim 3.

In Fig. 3 a known, circulating lockstitch looper 4 is shown with vertically arranged looper drive shaft. On the planar inner side 6 of a bobbin case upper part 1, a projection 7 arranged centrically to the center 3 of the direction is provided. The latter is thus located between the inside 6 and a flange -outside 17 of one of the bobbin case upper part 1 received Disc coil 16. The extension 7 has a circumferential groove 8. In the bobbin case upper part 1 is a small hole 13 and a Slot 18 is provided.

A disk 11 preferably made of spring steel has a centrally tapering towards its center slot 10. Fixed to the disc 11 - preferably on its in the installation position for Inside 6 facing side - is a corresponding to Fig.

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executed as a bent spring wire spring 5 connected to the a hook 12 is bent at the free end. A thread eyelet 2 - as can be seen from FIG. 4 - is also firmly connected to the disk 11. The fixed connection between the disc 11 and the Spring 5 or the thread eyelet 2 is preferably produced by soft soldering.

The disk 11 is inserted into the bobbin case upper part 1 in such a way that the thread eyelet 2 is caused by corresponding tilting of the disk is threaded through the slot 18. The disk 11 is then pressed onto the projection 7, whereby it is due to the slot 10 widens slightly and snaps into groove 8. Now the hook 12 is hooked into the bore 13. This takes the spring 5 the shape of a spiral spring clamped on one side with less than one turn. If the thread eyelet 2 is in the direction indicated by the arrow in 1 is pivoted, the spring 5 is thus tensioned. After releasing the pivoted thread eyelet 2, it moves under the influence of the relaxing spring 5 again in its starting position shown in FIG. Since the disk 11 is only concentrically around <3 the turning center 3 of the lockstitch looper 4 can pivot, the thread eyelet 2 also moves concentrically to the center of rotation 3.

Another embodiment according to claim 3 can be seen from FIG. Here, a leg 14 of the thread eyelet 2 runs in the circular ring-shaped Section 15. The latter is received by the groove 8 when the section 15 is printed over the projection 7. This execution has the advantage that in this case a slotted disc carrying the thread eyelet 2 can be dispensed with. Firmly with the thigh 14

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the spring 5 is connected at point 20, at the free end of which a hook 12 is bent. After section 15 on approach 7 pressed and the hook 12 was hung in the bore 13, the spring 5 acts like a spiral spring clamped on one side. i

The mode of operation of the upper part of the bobbin case 1 is described below

1 described with the concentrically pivotable thread eyelet 2: A disc bobbin 16 filled with bobbin thread 25 is inserted into the upper part 1 of the bobbin case, in such a way that the free thread end runs to the left. This means that the disc spool 16 rotates clockwise (see. Fig. 2) when the free end of the thread is pulled. When threading properly, the bobbin thread is first threaded through the slot 21, under the leaf spring 22, through the slot 23, the hole 24 and then through the clock of the thread eyelet 2 (see FIG. 2). During the normal sewing process, in which all the sewing needles are involved in the stitch-forming process, such a tensile force acts on the bobbin thread 25 that the thread eyelet swings into its front position against the spring force exerted by the spring 5. If a sewing needle is now switched off, ie it remains in its upper position during this period, an appropriate amount of bobbin thread is withdrawn from the disc bobbin 16 with each sewing material transport step, which is, however, not required for the stitch formation at the moment. Because of the now missing tensile force on the bobbin thread 25, the spring relaxes and the thread eyelet 2 pivots clockwise. This pulls back the excess amount of bobbin thread, ie the bobbin thread is kept relatively taut. This eliminates the otherwise unavoidable occurrence of relatively large loops on the underside of the sewing material

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avoided the amount of bobbin thread withdrawn during the
Corner sewing.

After switching on the sewing needle that was previously switched off during corner sewing, the new stitch formation starts again. The one for it
The required amount of bobbin thread is first removed from the supply of bobbin thread retained by the thread eye, the thread eye 2 being pivoted back into its front position. Only when it has reached this is the amount of bobbin thread held back used up. The amount of bobbin thread required for further stitches is now withdrawn from the disc bobbin 16 again.

Claims (3)

• · »it • · · · ι ι t ι 4800 Bielefeld11 'G / N / 022 / DE' - 2/1 protection claims; Wherein an integral first coil housing upper part of a double lock-stitch gripper which is adapted to receive a flanged bobbin for the lower thread winding between a plane inside of the coil-I the housing upper part and an outer side of a flange of the i pancake coil employed situated annular disc with B a so There is a pin around which the bobbin thread loops, s characterized by - That a thread eyelet (2) I is captively connected to the upper part of the pulley housing (1) and is concentric to the center of rotation (3) '; the lockstitch looper (4) is guided in a form-fitting manner, ti whereby the thread eyelet (2) can be pivoted against the action of a spring (5) which can be dimensioned independently of i'nr fs. • _ · · · · ι ι im a · ι 2. bobbin case upper part according to 'AhSprucn'Γ; · characterized in that a shoulder (7) with a circumferential groove (8) is provided on the flat inside (6) of the bobbin case upper part (1), since the -aine end the bent spring (5) is firmly connected to the disk (11), the disk (11) having a slot (10) directed towards its center, so that the groove (8) holds the disk (11) which is essentially secured against axial displacement receives that the free end of the spring (5) ending in a hook (12) is received by a bore (13), and that one leg (14) of the thread eyelet (2) is firmly connected to the disc (11). 3. Spulengehäu-se upper part according to claim 1, characterized in that the leg (14) of the thread eyelet (2) expires in an annular portion (15) which is received by the groove (8), and that one end of the bent spring (5) is firmly connected to the leg (14) and the hook (12) is received at the free end of the spring (5) by the bore (13). »I I