WO2012095106A2

WO2012095106A2 - Upper thread tensioner

Info

Publication number: WO2012095106A2
Application number: PCT/DE2012/100007
Authority: WO
Inventors: Harald Dinges
Original assignee: Xi'an Typical Europe Gmbh
Priority date: 2011-01-12
Filing date: 2012-01-12
Publication date: 2012-07-19
Also published as: WO2012095106A3; CN103314148A; DE202012100110U1; DE112012000457A5

Abstract

The invention relates to an upper thread tensioner, comprising two thread tension disks (1, 2), a spring element (3) for pressing the thread tension disks (1, 2) together and a step motor (4) for setting the distance between the two thread tension disks (1, 2) being provided. According to the invention, the spring element (3) is produced of an elastomer.

Description

Upper thread tensioner

The invention relates to a upper thread tensioning device according to the preamble of patent claim 1.

A usual in sewing machine upper thread tensioning device of the type mentioned is known from DE 102 04 237 AI. This consists of two thread tension discs, wherein a helical compression spring (spring element) is provided for compressing the thread tensioning discs and a drive for adjusting the distance between the two thread tensioning discs. The drive designated by the reference numeral 20 is formed in this solution typically as an electromagnetic coil (electromagnet). In paragraph [0120], however, the use of a stepper motor is also disclosed as an alternative, as in the preamble of patent claim 1.

Under a stepping motor is in particular a so-called synchronous motor to understand, in which the rotor (rotatable motor part with shaft) by a controlled stepwise rota ^¬ rendes electromagnetic field of the stator coils (not drehba ^¬ rer motor part) by a minimum angle (step) or be Many times can be rotated. It is thus a rotating drive, wherein the rotational movement for Abstandseinstel ^¬ ment of the two thread tensioning discs, for example via a spindle or the like is converted into a linear movement.

Although the use of an electromagnet according to DE 102 04 237 AI ensures a reliable sewing operation; however problema ^¬ shows the so-called phase of "airing" which is especially set when thread trimming and when the tension discs only slightly comparable to the thread may be tensioned. In this phase consists in electromagnetic ^¬ tables coils of the disadvantage that the accuracy of Positi ^¬ onseinstellung is strongly temperature dependent, that is to this phase at all to realize a control loop is it ^¬ conducive on the one hand measures the yarn tension and on the other hand, the electromagnet optionally correspondingly nachjus ^¬ animal.

Substituting instead of the electromagnet in the solution according to DE 102 04 237 AI, as proposed in paragraph [0120], a stepper motor, there are other problems: In a "soft" helical compression spring the travel for "airing" is very long, ie The stepper motor is definitely too slow for this application. If one instead a "hard" bendruckfeder use Schrau ^¬, so also in this case, a device for measuring the yarn tension would be needed, since the compression coil spring having To tolerances ^¬ particular close to its relaxed initial length due to its manufacturing process comparatively high, that is, one can not forward Leave that supposedly identical helical compression springs behave exactly the same in the application.

Even though DE 102 04 237 A1 is regarded as the closest prior art, for the sake of completeness reference is made to the following documents:

From DE 10 2008 011 509 AI a yarn tensioning device is known in which a lever mechanism is arranged between the stepping motor and the thread tensioning discs in order to realize the said "Lüf ^¬ th" when thread cutting can. Apart from the fact that in this document the figures are in contradiction to the description, the following is to be stated: If the stepper motor-side lever marked with the reference numeral 11 were longer than the one provided with the reference numeral 13, forming thread-squeegee-side levers (as shown in the figures), so would a reduction ratio, ie the stepper motor would definitely be too slow to realize a quick "airing". Conversely, an opposite lever fixation - as shown in the description - would reinforce the manufacturing tolerances for helical compression springs explained above, ie this alternative presupposes the thread ^tension sensor mentioned in paragraph [0026] of this document.

In the solutions according to the documents DE 195 21 116 AI, DE 196 33 223 AI and DE 10 2007 004 550 Al finally electromagnetic drives and no stepper motors are vorgese ^¬ hen, ie there are at least the same problems as in the aforementioned prior art ,

The invention has for its object a Oberfadenspann ^¬ device of the type mentioned above to improve.

This object is achieved with a Oberfadenspannvorrichtung of the type mentioned by the features listed in the characterizing part of claim 1.

According to the invention, it is thus provided that the spring element is formed from an elastomer.

In other words, according to the invention, the known from the prior art helical compression spring is replaced by a spring element which is formed of an elastomer.

Under an elastomer is a dimensionally stable, but elastic and in particular non-metallic material to hen hen ^¬ hen. This material may be a plastic, but also a natural product such as rubber or rubber. The solution according to the invention has a considerable advantage over the known prior art:

An elastomer is provided ^¬ (foamed and thereby compressible elastomer) ago typically by spraying or foaming. It can therefore be produced in a very simple manner, a plurality of exactly the same spring elements in which the unavoidable tolerance problem as in helical compression springs produced in the winding process does not exist. Only the use of an elastomer normally used for damping purposes means that can be completely dispensed with a sensor for measuring the thread tension in combination with a Schrittmo ^¬ gate, but simultaneously cut both the normal sewing operation and the time-critical "venting" in the yarn ^¬ - as experiments have shown - works optimally ..

(The USAGE ^¬ dung a foamed and thereby compressible elastomer is provided due to its favorable spring characteristic particularly preferred - - as mentioned above) only a few revolutions of the stepping motor are required to the position of with respect to the upper thread tensioning device results from the fact that thanks to the elastomer To be able to vary thread tensioning discs between a maximum clamping position and a fully unloaded position or the "Lüftposition" (or in other words: the thread tensioning discs are firmly clamped in a first rotational end position of the stepping motor against each other and formed in a second rotational end position of the stepping motor contactless to each other). The upper thread ^¬ jig according to the invention thus has a considerably higher speed of operation and precision in particular ^¬ sondere the "venting" as the aforementioned, known from the prior art solutions in a very compact design. Other advantageous developments of the invention Oberfadenspannvorrichtung result from the dependent claims.

The upper thread tensioning device according to the invention including its advantageous developments is explained in more detail below with reference to the drawing of a preferred embodiment.

It shows

Figure 1 schematically and partially cut the upper thread tensioning device according to the invention; and

Figure 2 shows another embodiment of the invention

Upper thread tensioning device with two pairs of thread tensioning disks.

The upper thread tensioning device shown in Figure 1, commonly used in sewing machines consists in a known manner of two thread tensioning discs 1, 2 for tensioning a thread (not shown), wherein a spring element 3 for compressing the thread tensioning discs 1, 2 (and thus for tensioning the thread) and a stepping motor 4 for distance adjustment or for pressure adjustment between the two thread tensioning discs 1, 2 is provided.

Essential for the upper thread tensioning device according to the invention is now that the spring element 3, which is particularly preferably designed as a flat-cylindrical body, consists of an elastomer. An elastomer is to be understood in summary to mean any, in particular non-metallic, elastically deformable material, such as rubber or the like. The use of an elastomer has the advantage that the ge ^¬ desired actuating forces are very exactly adjustable "thread trimming" without device for measuring the thread tension both in the "normal" sewing operation and the "ventilation" or. In addition, a more uniform introduction of force into or onto the thread tensioning disk 2 is possible with an elastomer. Because be ^¬ already a relatively low-power stepping motor is used, this also results in advantageously a very compact structure, the upper thread tensioning device, which, as mentioned, in a simple manner with a very high dimensional accuracy (low tolerances) can be produced or operable ,

Overall, the solution of the invention insbesonde ^¬ re is characterized in that the two thread tension discs can be achieved particularly quickly and aired, which is important in many Nähsituationen in particular during cutting of the thread and total - while reducing the components (absence of thread tension sensor ) - increases the Betriebsge ^¬ speed of the sewing machine.

As seen in Figure 1, is furthermore preferably provided that the spring element 3 is connected via an actuating element 5 to the stepping motor 4, wherein further preferably provided that extends between the actuator 5 and a thread tension disk 2 extending spring element 3 Minim ^¬ least in this area is designed as a preferably homogeneous solid body.

Particularly preferably, it is further provided that between the actuating element 5 and the stepping motor 4, a ^{Drehbewe ¬} tion of the stepping motor 4 in an axial movement of the actuating ^¬ elements 5 converting ^spindle element 6 is arranged. Under a spindle or a threaded spindle is quite general to understand a machine element that, together with other elements, converts a rotating movement into a translatory movement.

In this context, it is further provided that the actuating element 5 is displaceably, but rotationally fixed or secured against rotation to the two thread tensioning discs 1, 2 is mounted. The thread tensioning discs 1, 2 are circular and have an opening 7, 8 centrally. In addition, it is provided that one of the two thread tension discs 1 stationary and the other thread tension disc 2 is arranged movable for accommodated in a housing entspre ^¬ sponding stepping motor. 4

Further, as shown, preferably provided that the loading ^¬ tätigungselement 5 has a pin-shaped extension 9 and a thereto arranged, which is in contact with the spring element 3 Tel ^¬ lerelement 10, wherein the pin-shaped extension 9 per ^¬ weils an opening 7, 8 , 11 is formed on the two thread tension discs 1, 2 and the spring element 3 by cross.

The upper thread tensioning device according to the invention, the clamping effect on the thread for the success of the seam of the greatest influence works as follows: The thread (not Darge ^¬ represents) is located between the two yarn clamping disks 1, 2. In Figure 1, these at least one the thread thickness corresponding distance to each other, ie, the thread can be moved freely between the two thread tensioning discs 1, 2.

If tension is now to be applied to the thread, the stepping motor 4 is actuated, ie rotated. This Dre ^¬ hung is in an axial movement of Actuate the ^¬ restriction member 5, or more specifically on the spindle 6 of the pin-shaped Fortsat ^¬ zes 9 implemented, and in such a manner that the stiftför ^¬-shaped extension 9, both the openings 7, 8 at the thread clamping plates 1, 2 and the opening 11 engages on the spring element 3, and thus also move the plate member 10 in the direction of stepping motor 4.

This movement causes the thread between the thread tensioning discs 1, 2 is clamped, and this the more firmly, the longer the engine rotates, as by the axial movement of the spring element 3 an ever greater force on the thread tensioning disc

2 is exercised.

If the upper thread tensioning device is to be released or lifted, only one rotational movement of the stepping motor 4 in the other direction is required. Since the spring element 3 WUR relatively slightly deformed even at high holding voltage ^¬ en, thereby the starting position illustrated in Figure 1 is reached again quickly.

Finally, according to FIG. 2, it is provided that the upper thread tensioning device consists of two pairs of thread tensioning disks 1, 2 and each pair is a stepping motor 4 and a spring element

3 is assigned from an elastomer. All four thread tensioning discs 1, 2 are arranged one behind the other on a longitudinal axis, wherein a second actuating element 5 for the second pair of thread tensioning discs 1, 2 is provided. In the area of the thread tensioning discs 1, 2, the two actuating elements 5 are arranged concentrically with each other; In addition, a lever 12 is provided in order to arrange the two stepper motors 4 in a concentric arrangement of the actuating elements 5 parallel zueinan ^¬ offset. Such a solution with two Oberfadenspannvorrichtungen is particularly intended for double needle sewing machines. LIST OF REFERENCE NUMBERS

1 thread tension disc

2 thread tension disc

3 spring element

4 stepper motor

5 actuator

6 spindle element

7 opening

8 opening

9 pin-shaped extension

10 plate element

11 opening

12 lever

Claims

claims

1. Upper thread tensioning device comprising two thread tensioning ^disks (1, 2), wherein a spring element (3) for compressing the thread tensioning disks (1, 2) and a stepping motor (4) for spacing adjustment between the two thread tensioning disks (1, 2) is provided,

characterized,

that the spring element (3) is formed from an elastomer.

2. Upper thread tensioning device according to claim 1,

characterized,

the spring element (3) is connected to the stepping motor (4) via an actuating element (5).

3. Upper thread tensioning device according to claim 2,

characterized,

that a rotational movement of the stepping motor (4) into an axial movement of the actuating element (5) that converts spin ^¬ delelement (6) is arranged between the actuating element (5) and the Schrittmo ^¬ gate (4).

4. upper thread tensioning device according to claim 2 or 3,

characterized,

that the actuating element (5) is mounted displaceably on the thread ^¬ clamping disks (1, 2).

5. Upper thread tensioning device according to one of claims 2 to 4, characterized

the actuating element (5) is designed to be rotationally fixed relative to the two thread tensioning disks (1, 2).

6. Oberfadenspannvorrichtung according to one of claims 1 to 5, characterized

the thread tension discs (1, 2) are of circular design and have an opening (7, 8) centrally.

7. Upper thread tensioning device according to one of claims 2 to 6, characterized

that extending between the actuating element (5) and a thread tension disc (2) spring element (3) is designed as a Minim ^¬ least preferably homogeneous solid body in this area.

8. Upper thread tensioning device according to one of claims 2 to 7, characterized

that the actuating element (5) has a pin-shaped projections ^¬ set (9) and a thereto arranged, with the spring element (3) is in contact plate element (10).

9. upper thread tensioning device according to claim 8,

characterized,

the pin-shaped extension (9) is formed in each case with an opening (7, 8, 11) on the two thread clamping disks (1, 2) and on the spring element (3).

10. upper thread tensioning device according to one of claims 1 to 9, characterized

in that the thread tensioning disks (1, 2) are firmly braced against one another in a first end of rotation position of the stepping motor (4) and are formed without contact with each other in a second end of rotation position of the stepping motor (4).

11. Upper thread tensioning device according to one of claims 1 to 10,

characterized,

that it comprises two pairs of thread-tensioning disks (1, 2), wherein each pair is associated with a stepping motor (4) and a spring element (3) made of an elastomer.

12. Oberfadenspannvorrichtung according to claim 11,

characterized,

that all four thread tensioning discs (1, 2) are arranged one behind the other on a longitudinal axis.

13. Upper thread tensioning device according to claim 11 or 12,

characterized,

a second actuating element (5) is provided for the second pair of thread tensioning disks (1, 2).

14. Upper thread tensioning device according to claim 13,

characterized,

in that the two actuating elements (5) are arranged concentrically with one another in the region of the thread clamping disks (1, 2).

15. Oberfadenspannvorrichtung according to claim 14,

characterized,

in that a deflection lever (12) is provided so that the two stepper motors (4) can be arranged offset parallel to one another in the case of concentric arrangement of the actuating elements (5).