EP2050853B1 - Sewing machine and loop taker for sewing machine - Google Patents

Description

The invention relates to a sewing machine according to the preamble of claim 1 and a gripper system for a sewing machine according to the preamble of claim 6.

A sewing machine according to the preamble of claim 1 and a gripper system for a sewing machine according to the preamble of claim 6 are known from DE 100 25 852 A1 known. The DE 100 25 852 A1 shows a horizontal gripper, which has a pivotable about an axis parallel to the gripper drive shaft capsule fan, which rests with a button against a formed on the outer circumference of a control disk control cam. The capsule fan has a fan lever which engages with a formed at its free end stop in a recess of the bobbin case and cooperates there with stop surfaces. By appropriate design of the control cam, the movement of the fan lever is controlled so that the speed of the fan lever formed stop is very low when it hits the associated stop surface of the coil capsule. In addition, this ensures that overspinning of the bobbin capsule against the gripper direction of rotation is prevented. The low impact forces and the prevention of an overshoot make an extremely quiet running of the opening mechanism possible even at high speed. A precise stitch formation is not ensured here.

At one of the EP 1 576 224 B 1 known sewing machine, the control cam is rotatably connected to the transmission shaft and is driven directly by this with respect to the speed of the gripper only half the speed. The control cam is on an axial cam as formed frontal curve surface against which the button is pressed. In this embodiment is - as with all other conventional drives - the noise when hitting the holding web of the bobbin capsule on the housing cam very high.

The invention is therefore based on the object, a sewing machine and a gripper system for a sewing machine in such a way that the noise is significantly reduced.

This object is achieved according to the invention in a sewing machine according to the preamble of claim 1 by the features in the characterizing part of claim 1. It is further solved in a gripper system according to the preamble of claim 6 by the features in the characterizing part of claim 6. The essence of the invention is that the release of the coil capsule in the direction of rotation by appropriate pivoting of the fan lever immediately before striking the holding web of the bobbin capsule on the stationary cam largely interrupted chen so that the retaining land is stopped immediately before hitting the cam. He then comes to the cam only with an extremely low speed, with the result that the noise is significantly reduced.

The dependent claims give advantageous embodiments again.

Fig. 1

eine Seiten-Längsansicht einer Doppel-Steppstich-Nähmaschine,

Fig. 2

eine gegenüber Fig. 1 vergrößerte Darstellung eines Greifers mit Greiferlager der Nähmaschine entsprechend dem Ausschnitt II aus Fig. 1,

Fig. 3

eine Draufsicht auf eine Steuerkurve in stark vergrößerter Darstellung,

Fig. 4

eine Draufsicht auf den Greifer mit Kapsel-Lüfter gemäß dem Sichtpfeil IV in Fig. 1 in einer ersten Position der SpulenKapsel,

Fig. 5

eine perspektivische Draufsicht auf den Greifer mit SpulenKapsel und Stichlochplatte in der ersten Position gemäß Fig. 4,

Fig. 6

eine Fig. 4 entsprechende Draufsicht auf den Greifer in einer zweiten Position der Spulen-Kapsel,

Fig. 7

eine den Fig. 4 und 6 entsprechende Draufsicht auf den Greifer in einer dritten Position der Spulen-Kapsel,

Fig. 8

den Verlauf der Bewegung des Lüfter-Hebels des Kapsel-Lüfters in einem Koordinatensystem,

Fig. 9

ein Greifer-System in teilweise aufgebrochener Darstellung in einer gegenüber Fig. 2 abgewandelten Ausführung,

Fig. 10

eine Draufsicht auf das Greifer-System gemäß Fig. 9,

Fig. 11

eine Ansicht des Greifers nach Fig. 9 und 10 von unten mit einer am Greifer ausgebildeten Steuerkurve,

Fig. 12

eine Ansicht entsprechend Fig. 11 mit einer am Greifer angebrachten Steuerkurve,

Fig. 13

eine Draufsicht auf eine Steuerscheibe mit Steuerkurve und

Fig. 14

die Auslenkung des Lüfter-Hebels des Kapsel-Lüfters über den Drehwinkel der Steuerkurve für die Ausführung nach den Fig. 9 bis 13.

Further features, advantages and details of the invention will become apparent from the following description of an embodiment with reference to the drawing. It shows:

Fig. 1

a side longitudinal view of a double lockstitch sewing machine,

Fig. 2

one opposite Fig. 1 enlarged view of a gripper with gripper bearing of the sewing machine according to the section II from Fig. 1 .

Fig. 3

a top view of a control cam in greatly enlarged representation,

Fig. 4

a plan view of the gripper with capsule fan according to the viewing arrow IV in Fig. 1 in a first position of the bobbin capsule,

Fig. 5

a top perspective view of the gripper with spool capsule and tap hole plate in the first position according to Fig. 4 .

Fig. 6

a Fig. 4 corresponding plan view of the gripper in a second position of the coil capsule,

Fig. 7

a the Fig. 4 and 6 corresponding plan view of the gripper in a third position of the coil capsule,

Fig. 8

the course of movement of the fan lever of the capsule fan in a coordinate system,

Fig. 9

a gripper system in a partially broken representation in a opposite Fig. 2 modified version,

Fig. 10

a plan view of the gripper system according to Fig. 9 .

Fig. 11

a view of the gripper behind Fig. 9 and 10 from below with a cam formed on the gripper,

Fig. 12

a view accordingly Fig. 11 with a control cam attached to the gripper,

Fig. 13

a plan view of a control disk with control cam and

Fig. 14

the deflection of the fan lever of the capsule fan over the rotation angle of the cam for the execution of the Fig. 9 to 13 ,

In the Fig. 1 illustrated double lockstitch sewing machine has in a conventional manner an upper arm 1, a vertical stand 2 and a lower housing-like base plate 3. In the arm 1, an arm shaft 4 is mounted, via a needle bar 5 with needle 6 and is driven outgoing. Furthermore, a thread lever 7 is driven by it. Furthermore, the thread lever 7 is preceded by a needle thread 8 from a thread supply, not shown on the thread lever 7 to the needle 6, a thread tensioning device 9.

As the Fig. 1 and 2 can be seen, it is in the illustrated embodiment is a so-called column sewing machine. This means that on the base plate 3 serving as a gripper bearing housing vertical support, a so-called column 10 is attached to the upper end of a gripper bearing 11 is arranged. In this gripper bearing 11 is a vertical gripper 12, that is a about a vertical axis 13 rotatably driven double lockstitch gripper 12, stored. A gripper drive shaft 14, which drives the gripper 12 and can be driven about the axis 13, is additionally mounted in an angle gear 15 which is mounted on the base plate 3 and which is designed in the usual way as a bevel gear. The drive of the gripper drive shaft 14 via the angle reduction gear 15 by means of a transmission shaft 16, which in turn is driven by a toothed belt drive 17 of the arm shaft 4. The toothed belt drive 17 has a gear ratio of 1: 1. The angle gear 15 has a gear ratio of 1: 2. This means that the gripper 12 rotates twice when the arm shaft 4 and the transmission shaft 16 makes one revolution.

Above the gripper 12, a tap hole plate 18 is secured to the column 10 with a tap hole 19. The pot-shaped gripper 12 has a hook tip 20, which passes directly to the immersed through the needle hole 19 needle 6 and can take the guided in this needle thread 8. In the gripper 12, a coil capsule 21 is arranged, the order the axis 13 is freely rotatable relative to the gripper 12. The also upwardly open bobbin capsule 21 has a radially to the axis 13 outwardly and the tap hole plate 18 upwardly projecting retaining web 22 which is rotatably supported only by a few degrees between two formed on the bottom of the needle plate 18 cams 23, 24 is what will be discussed in detail below.

As in particular the Fig. 4 to 7 can be removed, located between the first cam 23 and the holding web 22, a first lateral air gap 25, between the holding web 22 and the needle plate 18, an upper air gap 26 and between the holding web 22 and the second cam 24, a second permanent lateral air gap 27. The air gaps 25, 26, 27 form at a middle position of the holding web 22 a continuous channel. In the bobbin capsule 21 there is disposed a bobbin 29 accommodating a bobbin thread 28, which is held in the bobbin capsule 21 by means of a releasable locking lever 30.

The coil capsule 21 has at its upper edge on a substantially radially to the axis 13 outwardly projecting fan cam 31 which cooperates with a fan lever 32. The fan lever 32 forms an arm of a capsule fan 33. Serving as a support for the fan lever 32 capsule fan 33 is designed as a substantially vertical, ie parallel to the axis 13 extending double-armed lever. It has a fan shaft 34 formed by a bolt, which is mounted in the column 10 about an axis 35 perpendicular to the axis 35 and loaded with a return spring 36.

Below the fan shaft 34, a button 37 formed by a lever is mounted on the capsule fan 33. On the gripper drive shaft 14 an annular control disk 38 is mounted, which has on its outer circumference a control cam 39 against which the button 37 abuts due to the restoring force of the return spring 36. The over the entire circumference of the control disk 38 extending, so closed control cam 39 has different radial distances from the axis 13, so that in one revolution of the gripper drive shaft 14 and thus the gripper 12 of the fan lever 32 back and forth going pivotal movement performs. The control disk 38 has a fastening ring 38a, which is fastened adjustably on the gripper drive shaft 14 by means of a clamping screw 38b, which is only indicated.

The gripper 12 with gripper drive shaft 14, control disk 38 with control cam 39, coil capsule 21 and capsule fan 33 forms a gripper system.

The basic operation is well known as in capsule fans 33. If the fan lever 32 is not applied to the fan cam 31, then the holding web 22 of the coil capsule 21 is due to the entrainment of the coil capsule 21 by the gripper 12 in the direction of rotation 40 against the first retaining cam 23 at. The second lateral air gap 27 is thereby enlarged, while the first lateral air gap 25 is closed. The fan lever 32 is so far pivoted so far due to the corresponding shape of the control cam 39 that between the fan cam 31 and the fan lever 32, a gap 41 of 1 to 1, 5 mm width is formed. In the associated position of the gripper 12 and the bobbin case 21, the reception of a thread loop formed by the needle thread 8 takes place through the hook tip 20. The bobbin thread 28 is guided via the locking lever 30 to the tap hole 19. With the rotation of the gripper 12, the cam 39 also performs a rotational movement in the direction of rotation 40, wherein the rotational speed of the control cam 39 corresponds to the rotational speed of the gripper 12.

With the rotation of the gripper 12, the thread loop of the needle thread 8 is guided in so far known and conventional manner to the largely stationary held coil capsule 21. Shortly before the thread loop has been maximally widened by the gripper 12, that is, it has been guided around the stationary coil capsule 21, a pivoting movement of the fan lever 32 is initiated by corresponding pivoting of the capsule fan 33 counter to the direction of rotation 40, by appropriate shaping the control cam 39. The retaining web 22 is lifted from the first retaining cam 23. Here, the holding web 22 is brought approximately in the middle between the two retaining cams 23 and 24, so that the first lateral air gap 25, the upper air gap 26 and the second lateral air gap 27 are continuously open. The needle thread loop can slide without resistance through the channel formed by the air gaps 25, 26, 27.

With the further rotational movement of the gripper 12 of the fan lever 32 is pivoted back by the further rotation of the control cam 39. The gap 41 between the fan lever 32 and the fan cam 31 is opened again, so that the thread loop can slide through this gap 41 without resistance and falls off the bobbin capsule 21, forming a lockstitch together with the bobbin thread 28.

It should be expressly mentioned that the capsule fan 33 performs a full stroke every rotation of the gripper 12, although only every second revolution of the gripper 12 is a stitch formation.

The above is explained in more detail for the illustrated embodiment:

Like that Fig. 3 and 5 can be seen, the control cam 39 has a maximum 42 and this approximately opposite a minimum 43, ie a maximum or minimum distance to the axis 13, on. If the button 37 is guided over the maximum 42, then correspondingly the fan lever 32 is not deflected. He has accordingly Fig. 8 the deflection is zero. This corresponds to a first position 44 of the fan lever 32 according to Fig. 4 and 5 , Accordingly, the coil capsule 21 is pivoted as far as possible against the direction of rotation 40. In other words, this means that the second air gap 27 has its smallest possible width. Correspondingly, the first air gap 25 has its greatest possible width a of approximately 1.5 mm, where 1.2 ≦ a ≦ 1.8 mm. In contrast, when the button 37 is guided over the minimum 43 of the control cam 39, against which it is pressed by the return spring 36, then the fan lever 32 is pivoted as far as possible in the direction of rotation 40 in a third position 45 and the fan cam 31 under education of the gap 41 lifted. The retaining web 22 of the coil capsule 21 is located on the first retaining cam 23 of the needle plate 18 at Fig. 7 is removable. Since the movements of the button 37 and the fan lever 32 are made in opposite directions about the axis 35, when the probe 37 at the minimum 43 of the control cam 39 has the curve after Fig. 8 their maximum.

Between the maximum 42 and the minimum 43 of the cam 39 is - based on the direction of rotation 40 behind the maximum 42 and before the minimum 43 - formed an intermediate region 46 in which the control cam 39 is an approximately circular cylindrical course concentric to the axis 13 of the gripper shaft 14, ie approximately constant distance to the axis 13, having. If the pushbutton 37 is guided over this intermediate region 44 of the control cam 39, there is essentially no pivoting movement of the pushbutton 37 and correspondingly no pivoting movement of the fan lever 34. This intermediate region 46 corresponds in the development accordingly Fig. 8 the second position 47 marked there. This intermediate region 46 starts approximately when the holding web 22 still has a distance b from the first holding cam 23, wherein the following applies to the distance b: 0.05 mm ≦ b ≦ 0.15 mm and preferably b ≈ 0.1 mm. When passing through this intermediate region 46 is still a pivoting of the probe 37 with correspondingly extremely reduced speed until the rest of the holding web 22 on the first retaining cam 23. By this soft application is a hard abutment of the retaining ridge 22 on the first retaining cam 23 and the associated noise prevented. Thereafter, the further pivoting of the button 37 and thus the fan lever 32, without the coil capsule continues to rotate. The gap 41 between the fan lever 32 and the fan cam 31 is thus opened up to the dimension c, where 1.0 mm ≦ c ≦ 1.5 mm.

As far as in the embodiment of the Fig. 9 to 14 same parts are present, the same reference numerals are used as in the previous description. As far as it is functionally identical, but constructively but slightly different parts, these are denoted by the same reference numeral with a prime line, without it in any case requires a new description.

That in the Fig. 9 to 14 illustrated gripper system is intended for a double lockstitch sewing machine, as it is basically in Fig. 1 is shown. The only difference is that the entire gripper system is built into the base plate 3, as is the case with sewing machines in general is common. This gripper system is thus intended for a so-called flatbed sewing machine.

The gripper system has a gripper bearing housing 52, in the lower part of which designed as a bevel gear angle reduction gear 15 is arranged. Above the gripper 12, the tap hole plate 18 'is attached.

The control disk 53 with control cam 54 is arranged in this embodiment on the gripper drive shaft 14 'facing bottom 55 of the otherwise unchanged gripper 12. The control disk 53 is formed as a flat disk. Against the also formed on its outer circumference cam 54 is also designed as a feeler lever button 56 of the capsule fan 33 'under the force of the return spring 36' at. Furthermore, in this embodiment, the fan shaft 34 'vertically, that is arranged parallel to the axis 13 of the gripper 12.

The in the FIGS. 11 and 12 shown control disk 53 may be integrally formed with the gripper 12, so be made together with this one piece, as in Fig. 11 is shown. But it can also - as in Fig. 12 indicated - be plugged onto the gripper 12. It is in this case rotatably connected to the gripper 12 by means of a driving pin 57 and positioned in its angular position relative to the gripper 12. In order to enable a relative angular adjustment between control disk 53 and gripper 12, a plurality of only indicated holes 58 can be formed on the underside 55 of the gripper 12 and / or in the control disk 53 at a small distance from each other, into which the driving pin 57 is inserted, so that an angular adjustment of the control disk 53 and thus the control cam 54 relative to the gripper 12 is reached.

The thickness d of the control disk 53 and thus of the control cam 54 in the direction of the axis 13 is very small. It is 2.0 mm ≤ d ≤ 5 mm. For the extent e of trained as a tactile lever button 56 in the direction of the axis 13 is that it must be slightly less than the thickness d. Insofar, 1.5 mm ≤ e ≤ 4.0 mm.

Again, the gripper 12 forms with gripper drive shaft 14 ', SteuerScheibe 53 with cam 54, coil capsule 21 and capsule fan 33' a gripper system.

While in the embodiment according to the Fig. 2 to 8 the fan lever 32 and the button 37 in opposite directions, that are pivoted oppositely directed, is in the embodiment of the Fig. 9 to 14 the fan lever 32 'pivoted in the same direction to the button 56. The control cam 54 has a maximum 42 ', a minimum 43' and an intermediate portion 46 ', which results from the same direction pivoting of fan lever 32' and button 56 that when crossing the maximum 42 'with the button 56 of the Fan lever 32 'is deflected maximum. He then has accordingly Fig. 14 the maximum deflection. This corresponds to the third position 45. When passing over the intermediate region 46 ', the second position 47 of the fan lever 32' results. When passing over the minimum 43 'then finally results in the first position 44 of the fan lever 32' with a deflection zero of the fan lever 32 '.

Claims (9)

1. Sewing machine comprising

   - an arm (1),

   - a base plate (3),

   - a needle (6) supported in the arm (1) for guiding a needle thread (8), the needle (6) being drivable for up-and-down movement,

   - a hook (12) which

   - - is drivable for rotation about an axis (13) in a direction of rotation (40) by means of a hook drive shaft (14, 14'), and

   - - comprises an underside (55) facing the hook drive shaft (14, 14'),

   - a bobbin case (21) which is mounted in the hook (12) so as to be freely rotatable relative thereto,

   - a case lifter (33, 33') which comprises

   - - a lifter lever (32, 32') and a sensor (37, 56) which is loaded by means of a spring (36, 36') and

   - a control curve (39, 54),

   - - which is drivable for rotation about the axis (13) of the hook drive shaft (14, 14') at the rotational speed of the hook (12),

   - - which is formed on the outer periphery of the control disc (38, 53) and

   - - which the sensor (37, 56) rests against,

   characterized
   in that the bobbin case (21) comprises a lifter cam (31) cooperating with the lifter lever (32, 32'),
   in that the bobbin case (21) comprises a retaining rib (22) which cooperates with a cam (23) which is stationary relative to the base plate (3) so as to prevent a rotation of the bobbin case (21) in the direction of rotation (40),
   in that the control curve (39, 54) has such a shape that the speed of the retaining rib (22) in the direction of rotation (40) is greatly reduced at a distance b in front of the stationary cam (23),
   for which purpose the control curve (39, 54) has a maximum (42, 42'), a minimum (43, 43') and a transition zone (46, 46') therebetween with an approximately constant distance to the axis (13), wherein the transition zone (46) starts when the retaining rib (22) still has the distance b towards the stationary cam (23), wherein applies: 0.05 mm ≤ b ≤ 0.15 mm.
2. Sewing machine according to claim 1, characterized in that to the distance b applies: b ≈ 0.1 mm.
3. Sewing machine according to one of claims 1 to 2, characterized in that the control curve (39, 54) is connected to the hook (12) in a non-rotational manner.
4. Sewing machine according to claim 3, characterized in that the control curve (39) is mounted to the hook drive shaft (14).
5. Sewing machine according to claim 3, characterized in that the control curve (54) is mounted to the underside (55) of the hook (12).
6. Hook system for a sewing machine, the hook system comprising

   - a hook (12) which

   - - is drivable for rotation about an axis (13) in a direction of rotation (40) by means of a hook drive shaft (14, 14'), and

   - - comprises an underside (55) facing the hook drive shaft (14, 14'),

   - a bobbin case (21) which is mounted in the hook (12) so as to be freely rotatable relative thereto, the bobbin case (21) comprising

   - a case lifter (33, 33') which comprises

   - - a lifter lever (32, 32') and a sensor (37, 56) which is loaded by means of a spring (36, 36'), and

   - a control curve (39, 54),

   - - which is drivable for rotation about the axis (13) of the hook drive shaft (14, 14') at the rotational speed of the hook (12),

   - - which is formed on the outer periphery of the control disc (38, 53) and

   - - which the sensor (37, 56) rests against,

   characterized
   in that the bobbin case (21) comprises a lifter cam (31) cooperating with the lifter lever (32, 32'),
   in that the bobbin case (21) comprises a retaining rib (22) which together with a stationary cam (23) prevents a rotation of the bobbin case (21) in the direction of rotation (40),
   in that the control curve (39, 54) has such a shape that the speed of the retaining rib (22) in the direction of rotation (40) is greatly reduced at a distance b in front of the stationary cam (23),
   for which purpose the control curve (39, 54) has a maximum (42, 42'), a minimum (43, 43') and a transition zone (46, 46') therebetween with an approximately constant distance to the axis (13), wherein the transition zone (46) starts when the retaining rib (22) still has the distance b towards the stationary cam (23), wherein applies: 0.05 mm ≤ b ≤ 0.15 mm.
7. Hook system according to claim 6, characterized in that the control curve (39, 54) is connected to the hook (12) in a non-rotational manner.
8. Hook system according to claim 7, characterized in that the control curve (39) is mounted to the hook drive shaft (14).
9. Hook system according to claim 7, characterized in that the control curve (54) is mounted to the underside (55) of the hook (12).

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