DE1485156A1 - Needle thread tensioning device for sewing machines - Google Patents

Description

HELMUT SCHROETER

8 Münehon 5
Papa-Sdunjd-Str. 1 Tel 241589

Fritz Gegauf Aktiengesellschaft. Bernina sewing machine factory, Steokborn (Switzerland)

Dr. Expl.

Needle thread tensioning device for
sewing machines

The purpose of the invention is to provide a thread thread tensioning device whose thread tensioning discs lie against one another and are arranged on a thread tensioning bolt so that the .The needle thread cannot work its way out of the thread tensioning disks jerkily while mowing, if the angle of wrap of the needle thread entering and exiting the tensioner on the tensioning pin is less than 90 °.

In most of the known sewing machines, the thread tensioning device is for the needle thread on the arm head below the thread take-up. In this arrangement, the thread tensioning device protrudes strongly protrudes from the head of the arm and largely takes away the unobstructed view of the needle and the sewing work. With these Thread tensioning devices run over from the thread spool The thread coming to the back of the stand, entering the tension and the thread leading to the thread dispenser is almost parallel to one another

- 1 April 11, 64 G

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and therefore wrap around the thread tensioning bolt of the thread tensioning device by almost 180 °. This arrangement was chosen because the large angle of wrap prevents the thread from wandering out prevented from tension during sewing.

To give the seamstress an unobstructed view of the needle and To provide the sewing work has recently been the thread tensioning device in the horizontal part of the machine arm has been installed. In these thread tensioning devices, the thread wraps around the thread tensioning bolt at an angle of less than 90 ° so that the incoming and outgoing thread runs through the tensioning disk groove on one side on the upper side of the tensioning bolt. As a result, the opposing clamping disks tilt in such a way that the clamping surfaces of the clamping disks unite Form wedge-shaped gap. The thread wanders while mowing to the point at which the wedge-shaped gap is widest, i.e. out of the tension. To with these thread tensioning devices To prevent the needle thread from wandering out of the thread tensioning device, the thread tension pre-tensioning must be placed upstream so that the incoming thread also exerts pressure on the thread bolt> clamping device takes place.

It is necessary to adjust the tension of the needle thread as much as possible To be able to regulate finely, the thread entering the tensioning device must not be braked by a gate tension, otherwise the required regulation option of the Prevents the thread at the thread tension and the tensioning device becomes illusory.

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In the subject matter of the invention, the disadvantages mentioned are this is improved by the tensioning device for the calf thread ivdttel has a one-sided pressure on the thread tensioning disks on the side of the needle thread passage to prevent the needle thread from wandering out of the tensioning device to prevent during sewing.

The drawing shows an embodiment of the invention object shown. Bs shows:

Fig. 1 is a front view of a sewing machine with a needle thread tensioning device, which in the horizontal part the sewing machine arm is installed; Fig. 2 shows a cross section through the threading slot of the

Sewing machine arm;
3 shows a partial longitudinal section through the upper part

of the sewing machine arm with a thread tension; 4 shows a cross section with thread tensioners lying opposite one another with inserted needle thread and pressure device which only acts on the upper half of the tensioning disks;
Fig. 5 shows a cross section through 2 opposing

Tensioning discs with integrated «· needle thread) 6 with a pressure piece designed as a guide sleeve

Bevel j
7 shows a pressure piece designed as a guide sleeve with

Pressure cam »;

-v: it 1 denotes the sewing machine base plate on which the sewing machine arm 2 is put on. The horizontal part of the Arm 2 is covered with an arm cover 3 and the front side

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of the arm head with a cover 4 from which a switch button 5 of the built-in sewing machine lamp protrudes. The sewing machine is driven in the known manner via a string of the handwheel 6. On the front side of the The sewing machine arm is the thread take-up slot 7, from which a thread take-up lever 8 protrudes. Below the thread take-up the thread regulator 9 is arranged. The bathing rod 10 with the needle 11 protrudes from the arm head. On the back side The machine is a spool holder 12 with the spool pins 13 and 14 arranged. 15 is the spool of thread from which the needle thread 16 is drawn. On the back of the machine is the hanging eyelet 17. At 18, the transverse sole seat is in the Arm cover 3 denotes, within which the thread tension known per se is incorporated. On both sides of the transverse slot 18 thread guides 19 and 20 are arranged. On the A support plate 21 is attached to the underside of the arm cover 3 with screws (not shown). She carries the thread tensioning bolt 22, which is fastened with the washers 23 and 24 and the nut 25 to the same. On the opposite side is the Clamping bolt 22 is mounted in the bore 26 of the support plate 21. In a known manner, the thread tensioning bolt 22 has a bore 27, in which the release pin 28 is inserted. It also has a transverse slot 29. As a template for the thread tensioning disk 31, the disk 30 is arranged on the thread tensioning bolt 22. The thread-tensioning disc 31 lies against this and the counter-tensioning disk 32. The tensioning disk 31 and the pressure piece 33 are fixed by the one in the support plate 21

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Locking pin 34 secured in the radial direction. The Druokatück 33 is from the transverse 35, who through the Queraohlitz 29 gett, durohsetzt. Against the pin 35 is in Pieilriohtung pressed with the release pin 28 to release the thread tension. The pressure side of the pressure piece 33 is designed so that the Sohrägfläohe 36 with its opposite thread tensioning plate 32 only above the thread tensioning bolt in Point contact is coming. The thread tension spring 38 is arranged between the pressure piece 33 and the bath tensioning nut 37. The adjustment of the thread tensioning nut 37 takes place with the sole plate 39 »which protrudes segment-like from the arm deocle 3 ha ^ and with the thread tensioning nut 37 is coupled to the hub so as to be longitudinally movable. When turning the Soheibe 37, the nut moves the thread 41 of the thread tensioning bolt 22.

The way it works is as follows: After the * asohine is threaded, the thread 16 over the hanging eyelet 17, Placed over the thread guide 19 and from here between the tensioning disks 31 »32 and pulled out of the thread guide eyelet 20 on the other side, it is suspended in the regulator 9 and guided up to the hole in the thread take-up lever 8 and then down through the eye of the needle 11 and after the presser foot has been lowered, the Druokstüok is created 33 exerts a pressure on the thread tensioning discs 31 and 32 which is above the thread tensioning bolt 22, the needle thread 16 the -cadenspannbolzen 22 with an angle smaller than 90 ° surrounds. As a result, the thread tensioning surfaces of the thread tensioning disks 31, 32 lie opposite one another in a wedge shape, with

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the wider part of the wedge points downwards. As a result, the needle thread 16 always lies on the thread tensioning bolt 22, since it finds greater and greater resistance as the clamping surface diameter of the clamping disks 31 and 32 increases, FIG. 4; he so cannot work from the thread tension while sewing. An explanation of this phenomenon is given in 5 shows a simple, generally customary thread tensioner, in which the position of the thread tensioning discs 31 and 32 when the needle thread 16 is inserted, it is exactly the opposite of what is shown in FIG. 4. Here are the The tensioning surfaces of the thread tensioning disks 31, 32 face each other in a wedge shape, i.e. with the broad part of the wedge facing upwards. At the Sewing ha? This, however, results in the needle thread 16 moving closer to the point when the tensioning disks 31132 run slowly over and over again works towards where it finds the least resistance, i.e. out of tension.

Of course, the device described can be varied. For example, the one-sided pressure can be achieved by connecting the guide sleeve with a pressure cam is provided. Furthermore, the compression spring can be laid on one side in such a way that the pressure on the clamping washers is only applied to the takes place above the clamping bolt a lying side.

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Claims (4)

PATENTAN3PRDE0HE 1.) Needle thread tensioning device with two or more einandei opposite Fadenepannsoheiben, which are arranged on a thread tensioning bolt and where the Umsohlonieneginkel the incoming and outgoing needle thread on the thread tensioning bolt is smaller than 90 °, because the tensioning device for the needle thread has means (33) which ei & tn one-sided print on the thread tensioning discs (31) (32) cause the side of the needle thread thread to prevent the needle thread from wandering out of the tensioning device during the To prevent near. 2. Needle thread tensioning device naoh claim 1, characterized in that the Druokorgan for the thread tensioning disks (31,32) as a spring-loaded guide sleeve (33), the the one-sided pressure on the thread tensioning discs on the Γ:, - which causes the passage side is formed. 3. calf thread tensioning device naoh claims 1 and 2, characterized in that the guide sleeve (33) is provided with a pressure cam and locked in its radial position is. 4. Needle thread tensioning device naoh claims 1 to 3, daduroh marked that the pressure side of the guide sleeve - 7 -909829/0521 (33) the one-sided. Pressure on the thread tension discs causes, formed as an inclined surface (36) is. Fritz Geagauf Aktiengesellschaft Bernina-Mhmaschinenfabrik: - 8 909829/052 1 COPY