EP1829998B1 - Sewing machine with a drive assembly for the driving elements for threading the upper thread through the eye of the needle - Google Patents

Description

The invention relates to a sewing machine with a drive arrangement for the drive elements of a Einfädlers for threading the upper thread in the eye of the needle according to the preamble of patent claim 1.

Drive arrangements for threading devices on sewing machines are known in many designs. They serve to relieve the operator of the sewing machine of tediously inserting the upper thread into the eye of the needle. Simple insertion aids are operated by hand, i. The upper thread is placed in a suitable tool and then this facilitates the threading process. In the case of automatic threading devices, the thread of the device must first be presented to the device before the latter then carries out the threading operation by means of separate drives in the sewing machine.

From the US 5 086 719 Such a threading device is known. In this device, the threader is slightly lowered by a stepper motor and the Einfädelhaken thereby introduced into the eye of the needle. This process is carried out by means of a servomotor, so an additional element. A park position, which is far above the sewing area, the known Einfädler can not take.

The most commonly used automatic threaders pivot the threader down a horizontal axis from a parking position in the upper arm down to the needle. There are also motorized threading known, in which, as in the manually operated, the threading along a parallel to the needle bar Vorlegerstange vertically down and pivoted from this position around the platen rod. These known Einfädelvorrichtungen need for lowering a suitable electric motor drive, such as a stepper motor, the latter via a rack on the threading the latter down and after threading back up. The pivoting movement is inevitably carried out by a curved path along which the device is additionally rotated at the end of the lowering movement to the Vorlegerstange.
Both the Einfädelvorrichtungen, which are mounted pivotably about a horizontal axis in the upper arm of the sewing machine, as well as those which are moved vertically by an electric motor, require relatively much space. This leads to a voluminous upper arm housing, which limits the direct eye contact of the operator on the sewing area.

An object of the present invention is to provide a sewing machine with a drive arrangement for the drive elements of a threader, which requires little space and can also be retracted in the parking position substantially completely in the upper arm and thus does not hinder the handling during sewing.

This object is achieved by a sewing machine with a drive arrangement for the drive elements of a threader with the features of claim 1. Advantageous embodiments of the device are described in the dependent claims.

It succeeds by the elimination of a separate own drive for the movements of the threading their space requirements to keep small, so that it fits into a slim housing. Furthermore, there are no monitoring devices which monitor or synchronize the mutual position of the needle bar and thus of the needle eye and the threading device. All movements necessary for threading are necessarily synchronized. The elimination of one or more additional drive motors for the threading device and, alternatively, also the regulator threading motor also reduces the control wall or the associated synchronization of the individual drives mentioned above.

Figur 1

eine schematische perspektivische Darstellung einer Nähmaschine mit abgesenktem Einfädler,

Figur 2a-d

vier verschiedene Stellungen des Einfädlers,

Figur 3a-d

eine schematische Darstellung des Funktionsablaufs des Antriebs der Fadeneinlegevorrichtung.

Reference to an illustrated embodiment, the invention will be described below. Show it:

FIG. 1

a schematic perspective view of a sewing machine with lowered threader,

Figure 2a-d

four different positions of the threader,

Figure 3a-d

a schematic representation of the functional sequence of the drive of the thread loading device.

In FIG. 1 is a schematic representation of a Domhalthaltnähmaschine 1 with a base plate 3, a free arm 5, also called forearm, and an upper arm 7 can be seen. The free arm 5 and the upper arm 7 are interconnected by the machine housing 9. In the front end of the upper arm 7, a threading device 11 is arranged, which is extendable from the bottom 13 of the upper arm 7. In FIG. 1 the threading device 11 is fully extended, ie lowered down. On the upper side of the upper arm 7, a Oberfadenspulenhalter is shown with an upper thread bobbin 15 schematically. Further, reference numeral 17 denotes a needle at the lower end of which a needle eye 19 is attached. The needle 17 is connected to the lower end of a needle bar 21. Behind the needle bar 21, a presser foot rod 23 is shown, at the lower end of the presser foot 25 is attached.

In the FIGS. 2a to 2d are the elements briefly described above, extracted from the sewing machine, reproduced schematically again. In FIG. 2a the pusher foot rod 23 is lifted with the presser foot 25 of the throat plate 27 on the free arm 5 by an amount a. The lifting of the presser foot 25 in a known manner by a fan lever (or motor), which is not shown for the sake of clarity. Parallel to the presser foot rod 23, a rack 29 is attached to the driver 31 and longitudinally guided. Between the lower end 33 of the rack and a boom 35 which is fixedly mounted on the presser foot rod 23, a spring 37 is clamped. With raised pusher foot 25, the spring is only slightly biased. The rack 29 is in meshing engagement with a pinion 39, which is driven by an electric motor, such as a stepper motor 41. With reference numerals 42a and 42b longitudinal guides for the presser foot bar 23 are designated.

In FIG. 2b is the presser foot rod 23 with the presser foot 25 with the fan lever (not shown) or lowered by motor to the throat plate 27. At the same time, the toothed rack 29 has been moved downwards by the stepping motor 41, and thus the spring 37 has additionally been tensioned. The clamping force of the spring 37 serves to press the presser foot rod 23 with the presser foot 25 on the needle plate 27 via the arm 35. With the Stepping motor 41 can consequently be set the pressing force of the presser foot 25 on the throat plate or the sewing material (not shown) between presser foot 25 and throat plate 27.
The two in the FIGS. 2a and 2b Functions shown are known from the prior art and are used in high-quality sewing machines.
In FIG. 2b It can also be seen that the driver 31, which is not present in conventional sewing machines, lies at a short distance above a two-armed lever 43. The two-armed lever 43 is hingedly hinged to a Einfädler 45. The first leg 43a of the lever 43 still engages under distance with the driver 31; the second leg 43b of the lever 43 carries at its free end a hook 43c. This is located in the FIG. 2b shown position of the rack 29 outside the vertical travel range of a Nadelstangenmitnehmers 47. The latter is connected to the drive device, short the needle drive 49. The needle drive 49 with a Nadelstangenmitnehmer 47 is known from the prior art and comprises, as in the Figures 2c and 2d shown, a crank mechanism 51. The driver 47 is in the in the FIGS. 2b to 2d Disconnected positions of the needle bar 21 is decoupled. If now the rack 29 is driven a little further down by the stepper motor 41 from the position in FIG. 2b in the position in Figure 2c , the driver 31 pivots the Leg 43a of the lever 43 in a clockwise direction such that the hook-shaped end 43c below the Nadelstangenmitnehmer 47 comes to rest ( Figure 2c ). Preferably, a suitable pin 53 is arranged on the Nadelstangenmitnehmer 47. Now the threader 45 can be driven down by the needle drive 49 via the needle bar driver 47 ( Figure 2d ).
When the threader 45 is lowered, a threading hook 55 is forcibly swung about a not-shown curve about the axis A of the threader 45, and the threading operation can be performed. The threading process will not be described in more detail, since this independent of the in the FIGS. 2a to 2d described method steps can be done by differently operating devices.

After the Einfädelvorgang the needle drive 49 leads the Nadelstangenmitnehmer 47 upwards, whereby at the same time the Einfädler 45 by the tensile force of a tensioned when driving down the Einfädlers 45 second spring 57 can return to the starting position.

Analogous to the embodiment in the FIGS. 1 and 2 for the movement drive of the threader 11 with the already existing drives for the needle bar 21 and the Presserfussanpressung can also transfer the upper thread to a deflection, which the Wrap angle of the thread brake 61 increases, and for insertion into the thread regulator (not shown) with an existing drive, namely the drive motor 59 for the thread brake 61 done. In the FIGS. 3a to 3d is shown schematically in four steps, as on the one hand, the structure of the braking force in the yarn brake 61 with the drive motor 59 of the yarn brake 61 takes place and how with the same motor a Fadenauslenkhebel 73 can be actuated.
In the illustrations in FIG. 3 is the yarn brake 61, which consists of two against each other resiliently pressed against each other discs, not shown. The two disks are located axially behind the yarn brake 61 shown schematically as a circular plate. A drive plate 63, the periphery of which is formed as a toothed ring, on which a driven gear 65 of the drive motor 59 meshes, 61 is disposed between the drive motor 59 and the yarn brake. On the drive plate 63, a toothed segment 67, which can be pivoted on the axis of rotation A of the drive plate 63, is arranged on the end side, which on one side comprises a nose 69. The nose 69 is in the zero position ( Figure 3c ) on a cam 71 on. A Fadenauslenkhebel 73 is pivotally mounted about an outside of the periphery of the drive plate 63 arranged pivot axis B. In the region of the articulation of the Fadenauslenkhebels 73, this has a toothed segment 75, which with the teeth of the Tooth segment 67 on the drive plate 63 meshes. At the free end of Fadenauslenkhebels 73, a driver hook 77 is formed.
Figure 3c represents - as already mentioned - the zero position of the drive plate 63, in which the first toothed segment 67 rests against the cam 71 and in the yarn brake 61, the two the yarn brake 61 forming discs are spaced, so that the upper thread can be inserted therein. In a known manner, after insertion of the thread by the drive motor 59, the yarn brake 61 and a spindle, which merges the two discs of the yarn brake 61, driven. In this case, the cam 71 moves on the drive plate 63 in the counterclockwise direction by approximately 180 ° ( FIG. 3b ). If the thread tension has to be increased even more, the driving disc 63 continues to rotate the drive disc 63 counterclockwise until the cam 71 approaches from the other side of the nose 69 on the first toothed segment 67 (cf. FIG. 3a ).
At the beginning of a threading process for the upper thread, the thread brake 61 is in the zero position according to Figure 3c , In order to obtain an optimal deflection of the upper thread in the thread brake 61 or to insert the thread in the thread regulator, the initially straight upper thread 79 must be deflected after the thread brake 61. This is done with the Fadenauslenkhebel 73, the driving hook 77 detects the upper thread and from the initial position X in the deflection position Y. transferred. In order to transfer the Fadenauslenkhebel 73 from the position X in the position Y, the direction of rotation of the drive motor 59 is reversed, so that the drive plate 63 rotates clockwise. In this case, the first toothed segment 67 is likewise rotated clockwise by the cam 71, thereby pivoting the thread deflection lever 73, which is in engagement with the toothed segment 67, into the position Y (FIG. 3d figure ).
Once the Fadenauslenkhebel 73 has reached the position Y, the upper thread jumps over a Umlenknase, not shown, and is guided there, so that the Fadenauslenkhebel 73 is returned by rotating the drive motor 59 in the opposite direction back to the starting position and further rotation of the motor 59 in the same direction of rotation, the thread brake 61 according FIG. 3b and / or 3a can be stretched. Accordingly, the drive motor 59 of the yarn brake 61 performs two completely different jobs: At the beginning of the threading operation, the yarn deflection lever 73 pivots out of the rest and catch position into the transfer position Y and subsequently serves to regulate the yarn brake 61.

Claims (7)

1. Sewing machine having a drive arrangement for the drive elements of a threader (11) for threading the upper thread into the eye (19) of the needle (17), comprising a needle bar (21) carrying the needle (17), a needle bar carrier (47), which is designed such as to be able to be coupled to and decoupled from the needle bar (21), a presser foot (25) on a presser foot bar (23), which presser foot (25) can be moved from a rest position into a working position by a lifting lever, and comprising an additional pressure device which can be driven by an electric motor (41), a lifting drive for a threader (11) that is mounted in a vertically displaceable manner, a threading hook (55) which is arranged at the lower end of the threader (11) and can pivot about a vertical axis, and a thread brake (61) for regulating the thread tension, characterised in that, in order to lower the threader (11) for the threading operation, the threader (11) is designed such as to be able to be connected to the needle bar carrier (47) when the needle bar carrier is decoupled from the needle bar (21).
2. Sewing machine according to claim 1, characterised in that, in order to move the threader (11) from the ready position into a parked position in the upper arm (7) of the sewing machine (1) and in order to move it out of the parked position into the ready position, the additional lifting movements of the threader (11) are brought about by the drive motor (41) of the pressure device for the presser foot (25).
3. Sewing machine according to either of claims 1 or 2, characterised in that, in order to couple the needle bar carrier (47) to the threader (11), a lever (43) which can be pivoted by the drive device of the presser foot (25) is articulated on the threading device (11).
4. Sewing machine according to claim 3, characterised in that the pressure device is designed such as to be able to move further downward in order to couple to the lever (43).
5. Sewing machine according to any one of claims 3 or 4, characterised in that the lever (43) is designed such as to be able to latch onto a pin (53) on the needle bar carrier (47).
6. Sewing machine according to any one of claims 1 to 5, wherein the thread brake (61) comprises a drive motor (59) for adjusting the thread tension, characterised in that, in order to regulate the thread tension, the drive motor (59) is operatively connected to a carrier disc (63), which carrier disc (63) in the first direction of rotation (-) is connected to the thread brake (61) and in the second direction of rotation (+) can be connected to a thread deflection lever (73) in order to move the thread deflection lever (73) from a rest position (X) into a deflected position (Y).
7. Sewing machine according to claim 6, characterised in that the thread deflection lever (73) can be pivoted by the carrier disc (63) arranged between the drive motor (59) and the thread brake (61), said carrier disc having a tooth segment (67) which engages with the thread deflection lever (73) when the carrier disc (63) is rotated in the second direction of rotation (+).

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