EP0542760B1 - Device for monitoring the looper-thread supply in a double-lock-stitch sewing machine - Google Patents

Abstract

Fixed to the bobbin (13) mounted in the shuttle (9) of a sewing machine (1) is a data carrier (22) in which data describing the amount and optionally the nature of the thread wound on the bobbin are stored. The data carrier (22) is scanned by a sensor preferably comprising a first (27) and a second (27') read/write head. After the thread has been wound on an empty bobbin (13'), the second read/write head (27') enters the data defining the thread supply into the data carrier (22) on the bobbin (13'). The first read/write head (27) is used, on completion of a sewing operation, to enter the data defining the current thread supply into the data carrier (22) on the bobbin (13) concerned, or to read the data off the data carrier (22). Thus the bobbin (13) can give information at any time on the instantaneous thread supply on the bobbin (13).

Description

The invention relates to a device for monitoring the looper thread supply according to the preamble of claims 1 and 10.

A thread monitoring device, which has the features of claim 1, is known from German laid-open specification DE-OS 36 25 630 A1. The known thread monitoring device essentially consists of a sensor unit, a data processing unit and a signal device. The sensor unit has a light source, for example a light transmitter, and a light receiver, for example a photodetector. A light beam emitted by the light source is directed onto a bobbin provided for storing the hook thread, which is embedded in a bobbin case, also referred to as the upper part of the bobbin case, of a rotating lockstitch hook. Said light beam penetrates an opening provided in the bobbin case and thus strikes an outside of a front flange, the outside being provided with black, light-absorbing and white, light-reflecting markings. The above-mentioned bobbin briefly executes a rotary movement within a period in which the amount of thread required for the formation of a lockstitch is withdrawn from the looper thread supply located on the bobbin. During this rotation of the coil, the sensor unit scans the alternating black and white markings, whereby electrical impulses are generated. These pulses are fed to a data processing unit and a signaling device, as a result of which the looper thread supply located on the bobbin is monitored. This monitoring is based on the evaluation of the constantly changing reflection conditions, which allow appropriate conclusions to be drawn about the rotation and the current hook thread supply of the bobbin. When a predetermined amount of remaining thread still on the bobbin is reached, the signaling device emits a visual and / or acoustic warning signal.

The disadvantage of the known monitoring device is to be seen in the fact that the aforementioned monitoring only relates to the states "bobbin full; bobbin empty; thread break", while it is not possible to make a statement about any state with regard to the thread supply present in each case.

It is also known from French Laid-Open No. 2 600 085 to provide reflective surfaces which can be scanned on the flange of the coil. With opto-electronic scanning of the reflection surfaces, pulses are generated which represent a measure of the looper thread supply located on the bobbin. Since the proposed solution does not provide any storage option for the data defining the hook thread supply, the bobbin-specific data describing the hook thread supply are lost as soon as the bobbin in question is removed from the hook and spatially separated from the sewing machine. From this document, a pulse detection via a marking on the outside of a flange of the bobbin when winding up as when sewing is known, but no indications can be derived therefrom with which the determination of the current filling level of the bobbin via the detected pulses and the geometric data of these Coil is possible.

The invention is therefore based on the object to further develop a generic device for monitoring the looper thread supply, and to show a method for monitoring the looper thread supply so that information about the current thread supply of the ready-to-sew bobbin thread bobbin at any time and at any one Filling quantity are available.

This object is achieved in the generic device for monitoring the hook thread supply by the features listed in the characterizing part of claims 1 or 10.

This object is achieved in the method according to the invention by the features listed in the characterizing part of claim 12.

With the device according to the invention it is advantageously achieved that the current thread supply of a hook thread bobbin can be called up at any time with regard to the filling quantity and possibly the nature of the wound sewing thread - starting from a full bobbin to an empty bobbin - because every change the filling quantity is written into a memory called an information carrier.

With the design according to claim 1, it is possible to use the bobbin equipped with the information carrier in mutually independent sewing machines, ie in their respective grippers.
With the design according to claims 6 and 7 it is ensured that the reading out or writing in of data defining the thread supply is carried out in the immediate vicinity of the lockstitch looper.

In the embodiment according to claim 8, a read / write station is provided which is arranged separately from the sewing machine and which reads out or writes in the thread supply Spool-defining data allowed in spatial separation from the sewing machine.

Another solution to the problem is realized with the features of claim 10. This solution is characterized by a particularly simple and inexpensive construction of the bobbin and a simply constructed sensor, which results in an inexpensive and reliable device for monitoring the hook thread supply of a sewing machine.

Useful and further advantageous developments of the device for monitoring the hook thread supply according to claim 1 are listed in the subclaims (claims 2 to 9) and according to claim 10 in subclaim 11.

The method according to the invention advantageously ensures that the seamstress is continuously informed about the filling level F and the remaining thread length L _R still on the bobbin by visual display, and that when a predeterminable tolerance threshold of the almost empty bobbin is reached, an acoustic and / or visual signal indicates that the bobbin thread bobbin is empty immediately.

Expedient and further advantageous developments of the method according to the invention are set out in subclaims 13 to 18.

Fig. 1

eine vereinfachte Vorderansicht einer Nähmaschine, die mit einer in der Nähmaschine integrierten Vorrichtung zum Überwachen des Greiferfaden-Vorrats ausgerüstet ist,

Fig. 2

eine vereinfachte Perspektivdarstellung auf einen umlaufenden Steppstich-Greifer und auf einen für die Überwachung der Greiferfaden-Spule vorgesehenen schwenkbaren Lese/Schreibkopf,

Fig. 3

eine Vorderansicht auf die Greiferfaden-Spule mit daran vorgesehenem, als konzentrische Magnetspur ausgeführten Informationsträger,

Fig. 4

eine Vorderansicht auf die Greiferfaden-Spule mit daran vorgesehenem, als sektorförmigen Magnetstreifen ausgeführten Informationsträger,

Fig. 5

eine Vorderansicht auf die Greiferfaden-Spule mit daran vorgesehenem, balkenförmigen Informationsträger,

Fig. 6

eine vereinfachte Vorderansicht einer Nähmaschine, die mit einer separaten Lese/Schreibstation zusammenarbeitet,

Fig. 7

ein Blockschaltbild der erfindungsgemäßen Vorrichtung, welches die Abtastung des an der Spule vorgesehenen Informationsträgers beim Aufwickeln wie auch beim Abwickeln erläutert,

Fig. 8

ein Blockschaltbild einer anderen Lösung gemäß dem Nebenanspruch 10,

Fig. 9

eine Ansicht auf den Flansch einer Spule für die andere Lösung,

Fig. 10

eine vereinfachte Perspektivdarstellung der für die Durchführung des Verfahrens notwendigen Komponenten,

Fig. 11

eine vereinfachte Aufspulvorrichtung zum Bewickeln einer Greiferfaden-Spule,

Fig. 12

eine vereinfachte Draufsicht auf die Aufspulvorrichtung,

Fig. 13

eine Seitenansicht einer in Schnittdarstellung gezeigten Spule in großem Maßstab.

Several exemplary embodiments are explained with reference to FIGS. 1 to 13.
It shows:

Fig. 1

1 shows a simplified front view of a sewing machine which is equipped with a device for monitoring the hook thread supply integrated in the sewing machine,

Fig. 2

a simplified perspective view of a rotating lockstitch looper and a swiveling read / write head provided for monitoring the looper thread bobbin,

Fig. 3

2 shows a front view of the hook thread bobbin with the information carrier provided thereon, designed as a concentric magnetic track,

Fig. 4

2 shows a front view of the hook thread bobbin with information carrier provided thereon, designed as a sector-shaped magnetic strip,

Fig. 5

2 shows a front view of the hook thread bobbin with the bar-shaped information carrier provided thereon,

Fig. 6

a simplified front view of a sewing machine that works with a separate read / write station,

Fig. 7

2 shows a block diagram of the device according to the invention, which explains the scanning of the information carrier provided on the spool during winding as well as during unwinding,

Fig. 8

2 shows a block diagram of another solution according to the dependent claim 10,

Fig. 9

a view of the flange of a coil for the other solution,

Fig. 10

a simplified perspective representation of the components necessary for carrying out the method,

Fig. 11

a simplified winding device for winding a hook thread bobbin,

Fig. 12

a simplified plan view of the winding device,

Fig. 13

a side view of a coil shown in section on a large scale.

In Fig. 1, a conventional sewing machine 1 is shown, which consists essentially of an arm 2 and a base plate 3, the latter two being firmly connected to one another in a known manner. An arm head 4 is provided on the front of the arm 2, in which, as is known, an up and down movable needle bar 5 is mounted. The latter is driven by an arm shaft 6 mounted several times in the arm 2, the right end of which protrudes from the arm 2 carries a handwheel 6a. As is known, the arm shaft 6 is driven by a sewing drive motor 7 via a traction means, which is only indicated symbolically in FIGS. 1 and 6, for example a V-belt. A horizontally mounted gripper shaft 8 is provided below the base plate 3 and is driven in a known manner from the arm shaft 6 via a toothed belt (not shown here). It goes without saying that the device according to the invention also extends to a gripper with a vertically mounted gripper shaft, this embodiment not being shown here. At the left end of the gripper shaft 8, a double-circulating lockstitch gripper 9 is fastened, which is known to consist of a non-rotatable bobbin housing part 10, a rotatably mounted gripper body 11 on the circumference of the latter, a bobbin housing upper part 12 (which is sometimes also referred to as a bobbin case) is) and a coil 13 embedded in the latter. The latter, after it has been inserted together with the upper part of the bobbin case 12 into the lower part 10 of the bobbin case, is rotatably mounted on a protruding sleeve 14. The coil housing lower part 10 carries the quill 14, which is thus part of the coil housing lower part 10. A nose 15 provided on the upper part 12 of the bobbin case engages in a recess 16 in the lower part 10 of the bobbin case 10 when inserting the upper part 12 of the bobbin case. The position of the coil housing upper part 12 in the coil housing lower part 10 is secured by a pivotable and displaceable flap 17 which, as is known, engages in a groove 18 provided at the front of the sleeve 14.

The coil 13 has a front flange 19 and a rear flange 20, both of which are connected to one another by a hub 21 according to FIG. 2. On the outside of the flange 19, an information carrier 22 is provided, which is made in a known manner either from sheet-like material, as a magnetic track (see FIGS. 3 and 4) or as a magnetic strip (see FIG. 5). The latter is made of thicker, sheet-like material, which is also used for the production of magnetic cards. The information carriers 22 just discussed, made of film-like or sheet-like material, are firmly connected to the outside of the flange 19 by using a suitable adhesive, preferably in such a way that they do not protrude beyond the outside of the flange 19. From Fig. 5 it is accordingly apparent that the magnetic strip made of thicker material is received by a groove 23 which is incorporated on the outside of the flange 19 with only a small depth.
In a further embodiment, not shown here, the information carrier 22 can be embodied by a transmitting and receiving device which is constructed in a hybrid circuit. This transmitting and receiving device consists of two relatively flat processors which are attached to the flange 19 or 20 of the coil 13 by a cast resin coating. In the vicinity of these processors, a very flat coil is provided on the opposite side of the flange 19 or 20, which is also connected to the relevant flange 19, 20 by a cast resin coating. An energy transfer then takes place through a stationary magnet arranged in the vicinity of this coil. The processors are activated by the latter. Due to the aforementioned optional attachment of the information carrier 22 to the front flange 19 or to the rear flange 20 (see FIG. 2), the sensor for scanning the information carrier 22 can either - as shown in FIG. 2 - in front of the gripper 9 or - here not shown - be arranged behind the gripper.

According to FIG. 3, a further mark 25 can also be attached to the outside of the flange 19, which is in contrast to its surroundings, for example as a dark spot in the form of a glued on, expediently somewhat recessed color field.
In the embodiment shown in FIG. 6, a further mark 25a is applied to the end face of the handwheel 6a.
In the embodiment characterized by a horizontally mounted gripper shaft 8 (see FIG. 2), an opening 26 according to FIG. 2 is provided in the front side of the coil housing upper part 12, which enables the unimpeded scanning of the mark 25 and / or the information carrier 22. The scanning just mentioned is made possible by a sensor device which, in the exemplary embodiment shown in FIGS. 1 and 2, essentially consists of a first read / write head 27 and a second read / write head 27 '. The latter is attached to the arm 2, while the read / write head 27 is attached to a swivel arm 29 which is pivotably mounted about a pin 30 mounted in the base plate 3. On the swivel arm 29, a piston rod 32 of a frame-fixed mover 33 engages via a known ball-and-socket joint 31, which was only shown symbolically in FIG. 2. The latter is embodied, for example, by a single-acting compressed air cylinder, which is pressurized with compressed air, which is taken from an external compressed air source 35, at times via a commercially available three / two-way solenoid valve 34. The time and duration of the application are specified by a controller 36. A tension spring 37 is also articulated on the swivel arm 29 and is connected to the base plate 3 in a frame-fixed manner on one side. Through the extendable piston rod 32, the swivel arm 29 is pivoted until it moves according to FIGS. 1 and 2 against an adjustable stop 38 which is mounted on the base plate 3. The adjustable stop 38 thus allows a minimal gap between the Read / write head 27 and an end face 42 on the gripper 9, which ensures unimpeded passage of the needle thread loop looping around the gripper 9.

As shown in FIGS. 1 and 6, a winding device 39 is provided on the arm 2, with which, as is known, an empty bobbin 13 'can be wound with the sewing thread. The winding device 39 is driven, for example, in a known manner by the arm shaft 6 via a bevel friction gear.
Of course, the winding (winding with sewing thread) of an empty bobbin 13 'can also be carried out in a separate station which is independent of the sewing machine 1.
In the control 36 mentioned above, a first counter / write unit 52 and a second counter / write unit 53 are provided, among other things. Of course, it is also possible for the two counter / write units 52, 53 to appear spatially separate from one another and not — as shown in FIGS. 1 and 7 — to be accommodated in a common controller 36. The counter / write unit 52 is connected via lines 50, 51 to the read / write head 27 '. The counter / write unit 53 is connected to the read / write head 27 via the lines 54, 55.

6 shows a further embodiment of the invention, which is characterized in that one of those for reading out the data contained in the information carrier 22 of the bobbin 13 and for writing in the current data defining the current thread supply of the bobbin 13 in the information carrier 22 Sewing machine 1 separate read / write station 40 is provided. With regard to the scanning of the information carrier 22 of a coil 13 'located in the winding device 39, a write head 28 is fastened to the arm 2 in accordance with the embodiment shown in FIG. 6 and cooperates with a further read head 49 fixed to the frame. The latter detects the mark 25a, which is provided according to FIG. 6 on the handwheel 6a connected to the arm shaft 6. The read / write station 40 also has a not shown here for the coil 13 a stationary read / write head 27 'and a controller 41. The latter contains a first counter / write unit 43 and a second counter / write unit 44. The write head 28 and the read head 49 are connected to the first counter / write unit 43 via the lines 45, 46. The read / write head 27 'is connected to the second counter / write unit 44 according to FIG. 6 via the lines 47, 48. Of course, it is also possible for the two counter / write units 43, 44 to appear spatially separate from one another and not — as shown in FIG. 6 — to be accommodated in a common controller 41.

In relation to the embodiment shown in FIG. 1 and in the block diagram according to FIG. 7, the embodiment described last and shown in FIG. 6 differs by the following: The coil 13 ′ placed on the winding device 39 is written to via the write head 28 with regard to its information carrier 22 , wherein the further reading head 49 determines the number of revolutions of the coil 13 'by scanning the mark 25a rotating with the handwheel 6a. The said number of revolutions of the bobbin 13 'is thus a measure of the thread supply on the bobbin 13. The pulses output by the write head 28 are delivered to the first counter / write unit 43 via the line 46. The pulses emitted by the read head 49 are likewise emitted to the counter / write unit 43 via the further line 45 (cf. FIG. 6).

In the exemplary embodiments described above, shown in FIGS. 1 and 6, the information carrier 22 serves, on the one hand, to receive or deliver data about the current thread supply of the bobbin 13 and, on the other hand, to make every revolution of the bobbin 13 detectable, for which purpose the information carrier 22 4 and 5 is designed. This goal can also be achieved with a differently designed coil 13, which according to FIG. 3 has another information carrier 22 has additional mark 25. The latter must then be scanned by a separate reading head, not shown in FIGS. 1 and 6 to 8.

The mode of operation of the device according to the invention with regard to the solutions shown in FIGS. 1, 6 and 7 is described below as follows:

In the block diagram according to FIG. 7, which relates to the embodiment shown in FIG. 1, the coil 13 'is provided with an arrow 56, with which the winding of the coil 13', that is to say the winding process for this coil, is symbolized. In contrast to this, FIG. 7 shows the bobbin 13 at another point with an arrow 57, which symbolizes the unwinding of the bobbin 13, that is to say the process during the sewing. Starting from the empty bobbin 13 ', a winding process is initially carried out in order to apply a thread supply to the bobbin 13'. As a result of the rotation of the coil 13 ', the information carrier 22 passing by the read / write head 27' is detected, so that with each revolution of the coil 13 'a pulse is delivered to the counter / write unit 52 via the line 51. After completion of the winding process, the counter / write unit 52 contains a sum of pulses, which represents a measure of the current thread supply of the bobbin 13 '. Following this, a transfer of the sum to the read / write head 27 ′ is carried out via the line 50, so that the said sum is stored in the information carrier 22. The process explained so far takes place on the winding device 39 of the sewing machine 1 or at an independent station for winding the bobbin 13 '. After a fully or partially filled bobbin 13 has been inserted into the gripper 9 of the sewing machine 1, the sum stored in the information carrier 22 is read out via the read / write head 27 and sent to the counter / write unit 53 via the line 55. During sewing, the bobbin 13 is rotated by pulling off the hook thread, wherein again each time the information carrier 22 passes the read / write head 27, ie each revolution of the spool 13, a pulse is detected and is likewise output via line 55 to the counter / write unit 53. In this respect, the impulses which detect the revolutions of the bobbin 13 during the sewing process represent a measure of the thread consumption.
In the counter / writing unit 53, the last-mentioned pulses are counted down from the sum which corresponded to the thread supply of the bobbin 13 before the sewing process just carried out and which - as mentioned above - was read into the counter / writing unit 53 at the beginning of the sewing process. As soon as the result from the sum recorded in the beginning in accordance with the thread supply of the bobbin 13 and the pulses in accordance with the thread consumption during a sewing operation takes the value zero or a defined residual value, the counter / write unit 53 emits a signal via an output line 58, which is known in the art Way is used via a signal device, not shown here, to display the thread consumption. At the same time, this signal serves to write the current value into the information carrier 22, which describes the current thread supply on this spool. For this purpose, the counter / write unit 53 transfers the current value via line 54 to the read / write head 27.

If the next sewing process is to be done with different colored sewing threads, a change of the bobbin 13, 75 is essential. Before the change, the current thread supply of the bobbin 13, 75 to be replaced is written into the associated information carrier 22, 68 in the manner described above, i.e. the information carrier 22, 68 of the said coil 13, 75 provides information about the current filling quantity of this coil 13 or coil 75 at any time.

Depending on the embodiment of the Information carrier 22 (compare the embodiments shown in Figures 3 to 5 or the not shown, but previously mentioned formation of the information carrier 22 by a transmitting and receiving device, which is constructed in a hybrid circuit), the reading in or reading out the sum in the or carried out from the information carrier 22 when the latter moves relative to the read / write head 27 or at a standstill when the information carrier 22 is appropriately assigned to the read / write head 27.

• 1.) Der Informationsträger 22 der Spule 13 wird in der separat von der Nähmaschine 1 angeordneten Lese/Schreibstation 40 abgetastet.
• 2.) Die zum Aufspulen in die Spulvorrichtung 39 eingesetzte Spule 13' wird hinsichtlich ihres Informationsträgers 22 von dem Schreibkopf 28 im Zusammenwirken mit dem weiteren Lesekopf 49, der gemäß Fig. 6 als Impulsgeber arbeitet, abgetastet. Selbstverständlich könnte in der Ausführungsform gemäß Fig. 6 anstelle des Schreibkopfes 28 und des Lesekopfes 49 auch der in Fig. 1 gezeigte Lese/Schreibkopf 27' verwendet werden. In allen weiteren Belangen ähnelt die Arbeitsweise der Ausführungsform gemäß Fig. 6 der Arbeitsweise der Ausführungsform gemäß der Fig. 1 und 7, so daß hier auf eine weitere Erläuterung der Arbeitsweise gemäß Ausführungsform nach Fig. 6 verzichtet werden kann.

The mode of operation of the invention according to the embodiment shown in FIG. 6 differs from the previously described embodiment shown in FIGS. 1 and 7 in the following points:

• 1.) The information carrier 22 of the bobbin 13 is scanned in the read / write station 40 arranged separately from the sewing machine 1.
• 2.) The spool 13 'used for winding in the spooling device 39 is scanned with respect to its information carrier 22 by the write head 28 in cooperation with the further read head 49, which operates as a pulse generator according to FIG. 6. Of course, in the embodiment according to FIG. 6, instead of the write head 28 and the read head 49, the read / write head 27 ′ shown in FIG. 1 could also be used. In all other respects the mode of operation of the embodiment according to FIG. 6 is similar to the mode of operation of the embodiment according to FIGS. 1 and 7, so that a further explanation of the mode of operation according to the embodiment according to FIG. 6 can be dispensed with here.

Another solution to the problem is described below in its structure in connection with the further FIGS. 8 and 9.

The sewing machine 1 shown in Fig. 1 is in the range of Spooling device 39 instead of the read / write head 27 'with a read head 60 and in the area of the gripper 9 instead of the read / write head 27 with a read head 61. A counter / write unit 62 and a control part 63 are contained within the controller 36. The controller 36 is connected to the read head 60 via a line 64 and to the read head 61 via a line 65. Furthermore, the control part 63 is connected in terms of circuitry via a connecting line 66 and the counter / write unit 62 via a connecting line 67 to an information carrier 68, which is provided as an external, that is to say separate, component and can have, for example, a magnetizable strip or a volatile memory component. The information carrier 68 contains individual storage locations, which are designated schematically in FIG. 8 with 69, 70 and 71. All storage locations of the information carrier 68 are each subdivided into an address field 72 and a data field 73, as is shown, for example, in FIG. 8 at the storage location 70. As can further be seen from this, the address field 72 bears the number 31 and the data field 73 the number 2604. According to the illustration in FIG. 8, the storage space 69 in its data field, which is not specified, contains the number 0 and the storage space 71 in its data field, which is not specified the number 733. Finally, the counter / write unit 62 is also equipped with an output line 74, which establishes a connection to a signal device, not shown, for example an indicator light.

In this solution, a coil 75 is used, which basically corresponds to the coils previously used in its construction. In addition, the coil 75 is provided on the outside of a flange 76 with a coding 77 which corresponds to an individual number of each individual coil. Because of this design, it is possible to identify each individual coil from a number of coils 75 in use.

9, the coding 77 is implemented with a wide line 78 and a plurality of narrow lines 79. Due to the formation of the lines 78 and 79, different pulse widths result, which the controller 36 compares with one another, so that the wide line is clearly recognized as the beginning of the coding 77. In this respect, the coding 77 is designed in accordance with the illustration in FIG. 9 in such a way that on the one hand an unambiguous counting of each revolution of the coil 75 by passing the coding 77 of one of the reading heads 60 or 61 and on the other hand a unique identification of each individual coil is possible.

The coding of the coil 75 takes place in that empty fields 80 on the circular ring surface 81 are correspondingly blackened with a felt-tip pen according to a coding algorithm. It is therefore easy to code or apply coding to the supplied neutral coils.
However, it is also conceivable to obtain information about a spool in that, in addition to the coding, a mark is provided which, with a specially provided reading head, serves to count each revolution of the spool.

The mode of operation of the device according to the invention with regard to the solution shown in FIGS. 8 and 9 is described as follows:
As in the previous description of the method of operation of the solution according to FIG. 7, a symbolic representation with the arrows 56, 57 is also selected in FIG. 8. Starting from an empty bobbin 75, a winding operation is first carried out on the winding device 39 (compare FIGS. 1 and 7) in order to apply a thread supply to the bobbin 75. As a result of the rotation of the spool 75, the coding 77 moves past the reading head 60 once each revolution of the spool 75.

Already after the first passing, the pulse sequence identifying the characteristic number of the coil 75 is delivered to the controller 36 via the line 64. The control part 63 of the controller 36 selects a memory location of the information carrier 68 which is associated with the coding 77 and which can be the memory location 69, for example. According to the representation in FIG. 8, the memory location 69 is assigned the number 0 in its data field 73, which is not described in any more detail. During the further winding operation, a pulse train identifying the spool 75 is delivered to the controller 36 via line 64 for each revolution of the spool 75 via the read head 60, the counter / write unit 62 recording each of these revolutions as a counting operation. The winding process is finally ended in the usual way by mechanical means, so that the bobbin 75 has a filling quantity of 100 percent. The counting state of the counter 62 reached at this point in time is transferred via line 67 to the data field of the previously selected storage location 69 and stored in the information carrier 68. In the manner described above, various bobbins 75 can be wound up, for example, with threads of different colors and with different fill quantities, so that corresponding data have been stored in the associated storage location 69 or 70 or 71.

For the sewing process, the operator of the sewing machine 1 inserts one of these wound bobbins into the gripper 9 so that the actual sewing process can then begin. When the code 77 passes the reading head 61 for the first time, a pulse sequence which characterizes the number of the coils 75 is delivered to the controller 36 via the line 65. In the control part 63, the storage location corresponding to the coil in question is selected again, which in FIG. 8 is the storage location 71. After this storage location 71 has been selected, the controller 36 receives information about the content of the value stored in the data field, which has the value 733 here. Each time the bobbin 75 rotates again during sewing, a further pulse sequence is sent via line 65 to the counter / writing unit 62, which is thus able to perform a counting process again and thus add up a number corresponding to the thread consumption required for the sewing process. As soon as the number corresponding to the thread consumption corresponds to the number stored in the data field of the addressed storage location (shown as number 733 in FIG. 8), the counter emits a signal via the output line 74. In addition to addressing the signal device (not shown here), this signal output also serves to initiate a stop operation via line 59 (see FIGS. 1 and 6) for the sewing machine 1 and to write a new information input into the updated data field. Since the thread supply of the bobbin 75 has now reached the value 0 in the example just explained, an entry is made with the value 0 in the addressed data field.

However, the last-mentioned sewing process can also take place in such a way that the bobbin 75 still has a certain amount of remaining thread due to a color change that becomes necessary, i.e. has a certain thread supply. In this case, too, the counter / write unit 62 outputs a difference value corresponding to the remaining thread supply of the bobbin 75 to the associated data field via the connecting line 67, which difference value was formed from the originally available thread supply and the thread consumption of the bobbin 75.

With regard to the method according to the invention, the following description applies:
The explosive gripper 9 shown in FIG. 10 of a lockstitch sewing machine 1 consists of the bobbin case upper part 12, the bobbin 13 and the bobbin case lower part 10. On the outside of the front Flange 19 of the coil 13 is applied at least one mark 25 in the form of light-dark sectors known per se, which is detected by a sensor 85. For this purpose, the opening 26 is provided in the upper part 12 of the coil housing, through which a light beam emitted by the sensor 85 - preferably an optical reflex coupler - and reflected by the flange 19 can pass. In this way, the rotation of the bobbin 13 during winding as well as the partial rotation of the bobbin 13 during sewing generate pulses which represent the turns of the looper thread located on the bobbin 13 and thus also the degree of filling F of the bobbin 13. These pulses are forwarded via a connecting line 86 to at least one counter 87, which in this case is designed as an up and down counter. However, it would be more expedient to use two or more separate counters 87 ', 87'', since it is usually always spooled during the sewing process and if only one counter 87 were used, the pulses would interfere with one another or waiting times would occur.
As a mark 25 for the pulse generation of the rotating bobbin 13, the provision of an opening or a plurality of openings, preferably having the same spacing, in the flange 19 is very expedient because this marking is very insensitive in the relatively rough sewing operation. Said openings are preferably designed as holes in the flange 19. Since this training has been used for a long time - for example to reduce the mass of steel coils - an illustration has been omitted here. To increase the accuracy of the pulse generation, it is advisable to arrange a large number of openings in the flange 19 or a large number of light-dark sectors on the outside of the flange 19.

In practical sewing operations, there are always several, more or less filled bobbins 13, which are used alternatively for a relevant sewing process. Around To avoid confusion, the coils 13 must be identified by visual coding or by machine-readable codes. The color nuance differentiation of the human eye can be used for the visual coding, in that each coil, at least on its flanges 19, 20, is provided on the outside with different colors - in the case of aluminum coils by the known anodizing process - generally 16 to 32 different ones Shades are sufficient.

A winding device known per se is shown in plan view in FIG. 12, wherein a winding wheel 89 driven by a motor 88 has a receiving pin 90. The latter takes up the empty bobbin 13, which is wound in a known manner during winding with a sewing thread 92 drawn off from an external spool 91. The latter is passed through a thread guide eyelet 93 and a non-positive disc tensioner 94, and then wound around a bobbin hub 95 in a known manner. It is expedient to first wind up a few turns by hand when the coil 13 is at a standstill.
The marks 25 provided on the outside of the flange 19 or the holes provided in the flange 19 are detected by a second sensor 96 and forwarded to the counter 87 via a line 97 (see FIG. 12), whereby - as mentioned above - it is very much It is expedient if a second counter 87 ″ is assigned to the sensor 96. The revolutions of the bobbin 13 that are carried out from the start of the winding up to the end of the bobbin winding process are thus monitored by the sensor 96, the pulses generated in this case being counted up by the counter 87, 87 ′ when the bobbin 13 is full, up to a maximum number of pulses Z _max . The exact determination of Z _max naturally requires a perfect winding process, in which the winding layers lie correctly on top of each other and in which the last winding layer is as close as possible to the Seal the outer diameter of the coil flanges 19, 20 flush.

When sewing - as already mentioned before - the revolutions of this bobbin caused by the thread take-off from the bobbin 13 are detected by the sensor 85 and at the end of this sewing process the pulse number Z _is determined by counting down the counter 87, 87 '. The latter represents the thread consumption of the bobbin 13 during sewing and is related to the diameter D _{R of} the remaining thread winding 98. The counters 87 and 87 ', 87''are operatively connected to a computer unit 100 via a line 99, as a result of which the number of pulses Z _max and Z _{ist are} entered into the computer unit 100. The latter also includes a keyboard 101 and a display 102. After entering the most important geometry data of the coil 13, namely the outer diameter D and diameter d of the coil hub 95 using the keyboard 101 and after reading in the pulse numbers Z _max and Z _is , the computer unit 100 Algorithms described below, the current degree of filling F of the coil 13 is calculated and shown on the display 102.

Finally, the computer unit 100 is operatively connected to a controller 104 of the sewing machine 1 via the lines 103.

wobei L_R die auf der Spule 13 vorhandene, durch den momentanen Wicklungsdurchmesser D_R definierte Fadenlänge darstellt. Unter der Voraussetzung, daß beim Aufwickeln einer Windung während des Aufspulvorgangs jeweils ein Impuls vom Sensor 96 erzeugt wird, ergibt sich die maximale Impulszahl Z_max der in Fig. 13 gezeigten ordnungsgemäß gefüllten Spule 13 bei folgenden Annahmen:

• innere Spulenbreite b gleich 10 Millimeter,
• maximaler Wickeldurchmesser D gleich 22 Millimeter,
• Nabendurchmesser d gleich 8 Millimeter,
• Stärke (Durchmesser) eines monofilen Nähfadens s gleich 0,5 Millimeter.

The sequence of the method according to the invention is described below:
When winding up an empty spool 13 by means of the spooling device shown in FIGS. 11 and 12, the sensor 96 detects the passage of the mark 25 during the rotary movement of the spool 13 and in the counter 87, 87 ″ the pulse number Z _{max is} determined by counting up. During sewing, the temporary rotational movement of the bobbin 13 is monitored by the sensor 85, which also detects the passage of the mark 25 and the count of pulses Z _is determined in the counter 87, 87 'by counting down. Those read into the computing unit 100 Pulse numbers Z _max and Z _ist are subtracted and give the pulse number Z _R , which represents the thread supply still present on the bobbin 13 after the sewing process. The degree of filling F of the coil 13 should only be able to be determined with the inclusion of the parameters Z _max , Z _ist , D and d. In order to arrive at such an algorithm, the following considerations are made:
The degree of filling F results from the relationship

where L _{R represents} the thread length present on the bobbin 13 and defined by the current winding diameter D _R. Provided that a pulse is generated by the sensor 96 when winding a winding during the winding process, the maximum number of pulses Z _{max of} the properly filled bobbin 13 shown in FIG. 13 results with the following assumptions:

• inner coil width b is 10 millimeters,
• maximum winding diameter D is 22 millimeters,
• Hub diameter d is 8 millimeters,
• Thickness (diameter) of a monofilament sewing thread s equal to 0.5 millimeter.

Under these assumptions, it follows that 20 turns occur in one layer on the coil shown in FIG. 13, because the width b equal to 10 millimeters divided by the thickness s equal to 0.5 millimeters gives the number of turns 20. The number of layers during proper winding is 14, because half the sum of D equal to 22 millimeters and d equal to 8 millimeters initially gives 7 millimeters, and in this amount the yarn thickness s equal to 0.5 millimeters occurs 14 times. The filled coil 13 thus contains 280 turns and, based on the assumptions previously made, the number of pulses Z _{max is} equal to 280.

woraus sich Z_max zu

ergibt.In general, Z _max can be derived from the relationship for this case:

which results in Z _max

results.

errechnet werden, die aus der Fachschrift "Vision und Identifikation Magazin" Vol 2, No. 1, Seite 29, Jahrgang 1988 entnehmbar ist. Bei stark bauschenden oder auftragenden Nähfäden wird der eben angesprochene theoretische Durchmesser s noch von einem Kompressionsfaktor K ≈ 0,89 beeinflußt. Für den nachfolgend abzuleitenden Algorithmus spielt die Garnstärke s wie auch die innere Breite b der Spule 13 keine Rolle, weil diese Größen durch rechentechnische Kürzung herausfallen. Begründet wird diese Behauptung damit, daß die Ermittlung des aktuellen Füllungsgrades F sich stets nur auf ein und dieselbe Spule 13 bezieht.For the twisted yarns that occur very frequently in practice, the strength of the sewing thread must be taken from the relationship

can be calculated from the technical specification "Vision and Identification Magazine" Vol 2, No. 1, page 29, born in 1988. In the case of bulky or bulky sewing threads, the theoretical diameter s just mentioned is still influenced by a compression factor K ≈ 0.89. For the algorithm to be derived below, the thread thickness s and the inner width b of the bobbin 13 are irrelevant, because these quantities are eliminated due to the mathematical reduction. This claim is justified by the fact that the determination of the current degree of filling F always relates only to one and the same coil 13.

Werden bei aufgebrachter Windung "N Impulse" erzeugt, so ist Z_max durch N zu dividieren.
Definiert man die Restfadenlänge auf der Spule 13 mit L_R, so ergibt sich der darauf bezogene, aktuelle Füllungsgrad F der Spule aus

worin

und

ist.The maximum length L _max of the perfectly filled thread winding wound on the bobbin 13 results from:

If "N pulses" are generated with the turn applied, Z _max must be divided by N.
If one defines the remaining thread length on the bobbin 13 with L _R , the resulting current filling degree F of the bobbin results

wherein

and

is.

woraus sich nach Kürzung die Beziehung ergibt:

Um die Größe D_R aus den beiden letzten Gleichungen zu eliminieren, wird der Füllungsgrad F aus einer weiteren Beziehung abgeleitet, die auf folgender Überlegung beruht:
Die Fadenlänge L_max ist in einem zylindrischen, rohrförmigen Fadenwickel mit den Abmessungen D, d und b unterbringbar, wobei der Fadenwickel ein Volumen V_max einnimmt.
Die Restfadenlänge L_R ist in einem weiteren Fadenwickel mit den Abmessungen D_R, d und b unterbringbar, wobei letzterer ein Volumen V_R einnimmt.
Damit ist der Füllungsgrad F auch aus der Beziehung

berechenbar.By inserting:

from which the relationship results after shortening:

In order to eliminate the quantity D _R from the last two equations, the degree of filling F is derived from a further relationship, which is based on the following consideration:
The thread length L _max can be accommodated in a cylindrical, tubular thread package with the dimensions D, d and b, the thread package taking up a volume V _max .
The remaining thread length L _R can be accommodated in a further thread package with the dimensions D _R , d and b, the latter taking up a volume V _R.
The degree of filling F is also out of the relationship

predictable.

Durch algebraische Vereinfachung folgt hieraus:

$${\text{V}}_{\text{R}}{\text{=(D}}_{\text{R}}\text{² - d²) ·}\frac{\text{π}}{\text{4}}\text{· b}$$

Ferner ist:

Vereinfacht ergibt sich hieraus:

$${\text{V}}_{\text{max}}\text{= (D²- d²)·}\frac{\text{π}}{\text{4}}\text{· b}$$

Somit ergibt sich:

Durch Gleichsetzung beider den Füllungsgrad F beschreibenden Gleichungsseiten ergibt sich:

oder in anderer Schreibweise:

Durch Vereinfachung ergibt sich:

und daraus folgt:

oder nach Auflösung

Nach weiterer Vereinfachung folgt aus der letzten Beziehung

Wird diese Formel in die oben abgeleitete Beziehung

eingesetzt, so ergibt sich schließlich:

Aus dieser Formel ist ersichtlich, daß zur fortlaufenden Ermittlung des Füllungsgrades F durch die Rechnereinheit 100 lediglich folgende Parameter erforderlich sind:

• die beim Aufspulen ermittelte und in einem Maximalwertspeicher abgelegte Impulszahl Z_max,
• die während des Nähens fortlaufend ermittelte Impulszahl Z_ist, welche am Ende eines Nähvorgangs den Fadenverbrauch wie auch die noch auf der Spule 13 vorhandene Restfadenlänge ausweist,
• die Geometriedaten D und d, welche - da sie maschinenspezifische, konstante Werte darstellen - nur einmal in die Rechnereinheit 100 eingelesen werden müssen.

Here is:

By algebraic simplification it follows from this:

$${\text{V}}_{\text{R}}{\text{= (D}}_{\text{R}}\text{² - d²) ·}\frac{\text{π}}{\text{4th}}\text{· B}$$

Furthermore:

In simple terms, this results in:

$${\text{V}}_{\text{Max}}\text{= (D²- d²) ·}\frac{\text{π}}{\text{4th}}\text{· B}$$

This results in:

Equating both equation pages describing the degree of filling F results in:

or in another spelling:

Simplification results in:

and it follows:

or after dissolution

After further simplification follows from the last relationship

This formula is in the relationship derived above

used, the result is:

It can be seen from this formula that only the following parameters are required for the continuous determination of the degree of filling F by the computer unit 100:

• the number of pulses Z _max determined during winding and stored in a maximum value memory,
• the continuously detected during the sewing pulse number _Z, which at the end of a sewing operation identifies the yarn consumption as well as the still present on the reel 13 remaining thread length,
• the geometry data D and d, which - since they represent machine-specific, constant values - only have to be read into the computer unit 100 once.

• baldigen Spulenwechsel anzuzeigen,
• nachfolgende Operationen einzuleiten, z.B. Fadenabschneiden, Drückerfußlüften und andere,
• die Nähmaschine stillzusetzen,
• den Sensor 85 in Verbindung mit der Rechnereinheit 100 auf eine andere Betriebsart - z.B. als Grenzfadenwächter - umzuschalten, um somit das Ausbleiben der Impulse durch Fadenbruch vom Spulenende zu unterscheiden.

The results of the automatic fill level calculation can be forwarded to the controller 104 of the sewing machine 1 in order to

• to announce an early change of bobbin
• initiate subsequent operations, e.g. thread trimming, presser foot lifting and others,
• to stop the sewing machine,
• to switch the sensor 85 in connection with the computer unit 100 to another operating mode - for example as a limit thread monitor - in order to distinguish between the absence of the pulses due to thread breakage and the end of the bobbin.

unter der Voraussetzung berechnet wird, daß beim Abwickeln einer Windung von der Spule 13 "N Impulse" erzeugt werden.In addition to the indication of the degree of filling F on the display 102, the remaining thread length L _R can also be shown, which is calculated by the computer unit 100 according to the formula

on the assumption that 13 "N pulses" are generated when a turn is unwound from the coil.

Claims (18)

1. A device for monitoring a looper-thread supply of a double lock-stitch sewing machine having

   - a looper (9),

   - a bobbin (13), which receives the supply of looper thread and is inserted turnably in the looper (9),

   - at least one marking which is provided on the outside on a flange (19) of the bobbin (13),

   - a sensor device which has a sensor to detect the marking during the sewing process, and

   - a control (36, 41) which is connected to the sensor device and gives off a signal when the supply of looper thread is used up,

   characterized by the fact that the marking is developed as a data carrier (22) which is fastened on the bobbin (13) and contains the data defining the existing supply of looper thread.
2. A device according to Claim 1, characterized by the fact that the data carrier (22) is developed as a sector-shaped or rectangular magnetic strip.
3. A device according to Claim 1, characterized by the fact that the data carrier (22) is developed as a circular magnetic track which extends concentrically to the center of the bobbin (13), and that a mark (25), by which the counting of the number of turns affecting the supply of looper thread can be effected, is provided on the bobbin (13).
4. A device according to Claim 3, characterized by the fact that the mark (25) is distinguishable by contrast from the outside of the flange (19) and from the data carrier (22).
5. A device according to Claim 1, characterized by the fact that the data carrier (22) is developed as a hybrid circuit consisting of transmitting device and receiving device.
6. A device according to Claim 1, characterized by the fact that the sensor device has, as first sensor, a read/write head (27) which is mounted swingably on a base plate (3) and directed towards the data carrier (22) of the bobbin (13) and, as second sensor, another read/write head (27') which is directed towards the data carrier (22) of another bobbin (13') which is inserted into a winding device (39) of the sewing machine (1).
7. A device according to Claim 6, characterized by the fact that the read/write head (27) can be swung by a mover (33) so far in the direction towards the data carrier (22) that a needle thread loop extending around the looper (9) can pass unimpeded between an end side (42) of the looper (9) and the read/ write head (27).
8. A device according to Claim 1, characterized by the fact that the sensor device comprises essentially the read/write head (27'), which is provided in a separate read/write station (40), is directed to the data carrier (22) of the bobbin (13) and acts as first sensor, and the further read/write head (28) which acts as second sensor and is directed to the data carrier (22) of a further bobbin (13') which is inserted into the winding device (39) of the sewing machine (1).
9. A device according to Claim 8, characterized by the fact that the sensor device comprises essentially:

   - the read/write head (27'), which is provided in the separate read/write station (40), is directed to the data carrier (22) of the bobbin (13) and acts as first sensor,

   - a write head (28) acting as second sensor, which is directed to the data carrier (22) of the bobbin (13'), and

   - a read head (49) which acts as third sensor, is directed to a mark (25a) on the hand wheel (6a), and cooperates with the write head (28).
10. A device for monitoring a looper-thread supply of a double lock-stitch sewing machine having

    - a looper (9),

    - a bobbin (75), which receives the supply of looper thread and is inserted turnably in the looper (9),

    - at least one marking which is provided on the outside on a flange (76) of the bobbin (75),

    - a sensor device for detecting the marking during the sewing process, and

    - a control (36 which is connected to the sensor device and gives off a signal when the supply of looper thread is used up,

    characterized by the fact that

    - the marking has a coding (77) for identification of the bobbin (75),

    - at least one sensor which forms part of the sensor device and recognizes the coding (77),

    - an external data carrier (68) having a plurality of storage places (69, 70, 71) is provided, said places permitting the depositing of the coding (77) of the corresponding bobbin (75), as well as the data defining their instantaneous supply of looper thread, and

    - a counter/recording unit (62) contained in the control (36) is connected to the data carrier (68).
11. A device according to Claim 10, characterized by the fact that

    - the sensor device has essentially a read head (61) acting as first sensor which is directed to the coding (77) of the bobbin (75) inserted in the looper (9) and a further read head (60) which acts as second sensor, the latter being directed to the coding (77) of the bobbin (75) present in the winding device (39), and

    - the counter/recording unit (62) is functionally connected, upon sewing, to the first read head (61) and upon winding, to the second read head (60).
12. A method of monitoring the looper-thread supply in a double lock-stitch sewing machine in which, by detection of a marking provided on the outside of a bobbin (13) present in the looper (9), pulses are detected by a sensor (96) upon the winding due to the rotation of the bobbin (13) and are given off to at least one counter (87) and in which, furthermore, pulses are detected during the sewing by the intermittent rotation of the bobbin (13) by a further sensor (85) and given off to at least one counter (87), characterized by the fact that

    - the identification of the bobbin (13) is effected by a marking on the outside of a flange (19) on the bobbin (13),

    - the outside of the flange (19) of the bobbin (13) has further marks (25) which are detected by a first sensor (96) upon winding as pulses influencing the degree of filling F of the bobbin (13) and are incremented by the counter (87, 87') to the number of pulses Z_max,

    - the marks (25) are detected during the sewing by a second sensor (85) as pulses which affect the consumption of looper thread and decremented in the counter (87, 87') to the pulse number Z_act,

    - the diameter D of the bobbin (13) as well as the diameter d of the bobbin hub (95) are inputted via a keyboard (101) forming part of a computer unit (100),

    - the number of pulses Z_R influencing the instantaneous degree of filling F of the bobbin (13) is calculated in the computer unit (100) by subtraction of Z_max and Z_act, and

    - the number of pulses Z_max and the corresponding thread length L_max, as well as the number of pulses Z_act and, at the end of the sewing, the number of pulses Z_R as well as the remaining length of thread L_R still present at this time on the bobbin (13) are indicated on a display (102) forming part of the computer unit (100).
13. A method according to Claim 12, characterized by the fact that the pulses detected by the sensors (85, 96) are fed either to the counter (87) designed as incremental and decremental counter or to two separate counters (87', 87'') for each sensor (85, 96) of which the counter (87'') cooperating with the sensor (96) operates as incremental counter and the counter (87') cooperating with the sensor (85) as decremental counter.
14. A method according to Claim 12, characterized by the fact that the marking provided for the identification of different bobbins (13) is unmistakably associated by visually readable or machine-readable marking with the counter (87, 87', 87'') or the counting values (pulse numbers Z).
15. A method according to Claim 12, characterized by the fact that, upon the action of the sensor (85) on the counter (87, 87'), start, stop or thread-cut signals can also be connected, and a signal is given off to the counter (87, 87') upon the absence of pulses.
16. A method according to Claim 12, characterized by the fact that after the inputting of the bobbin geometrical data (D, d) and after the entry of the pulse numbers Z_max and Z_act into the computer unit (100), the degree of filling F is continuously calculated in said computer unit in accordance with the formula

    

    and shown in the display (102), and that this value is forwarded to the machine control (104) for the preparation of stop, bobbin-change or disturbance operations.
17. A method according to Claim 16, characterized by the fact that, in accordance with the formula for the length of filling L_max, upon the inputting or measurement of the yarn size s and/or stitch length and/or thickness of fabric and action of the pulses detected by the sensor (85) via the computer unit (100), the sewing path still to be sewn is continuously calculated and shown in the display (102).
18. A method according to Claim 16, characterized by the fact that by automatic or manual inputting of the length of seam to be produced into the keyboard (101), the computer unit (100) calculates whether the length of seam can still be sewn.

Images