EP0387255B1 - Sewing machine with catch thread device - Google Patents

Sewing machine with catch thread device Download PDF

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Publication number
EP0387255B1
EP0387255B1 EP88907691A EP88907691A EP0387255B1 EP 0387255 B1 EP0387255 B1 EP 0387255B1 EP 88907691 A EP88907691 A EP 88907691A EP 88907691 A EP88907691 A EP 88907691A EP 0387255 B1 EP0387255 B1 EP 0387255B1
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EP
European Patent Office
Prior art keywords
counter
thread
sewing machine
input
signal
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EP88907691A
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German (de)
French (fr)
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EP0387255A1 (en
Inventor
Walter Hager
Edgar Butzen
Günther DENUELL
Kurt Arnold
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GM Pfaff AG
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GM Pfaff AG
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    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05B—SEWING
    • D05B51/00—Applications of needle-thread guards; Thread-break detectors
    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05B—SEWING
    • D05B59/00—Applications of bobbin-winding or -changing devices; Indicating or control devices associated therewith
    • D05B59/02—Devices for determining or indicating the length of thread still on the bobbin
    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05B—SEWING
    • D05B69/00—Driving-gear; Control devices
    • D05B69/36—Devices for stopping drive when abnormal conditions occur, e.g. thread breakage

Definitions

  • the invention relates to a sewing machine according to the preamble of claim 1.
  • a thread monitor for a sewing machine which has a counter with a counting, a resetting and a precharging input serving for the input of counting values.
  • the pulses of a pulse generator generating a predeterminable number of pulses each time the main shaft is rotated are fed to the counting input, while a pulse generator driven by thread retraction is connected to the reset input.
  • Each pulse at the reset input resets the counter to an output value. Starting from this value, the counter sums the pulses at the counter input until it is reset by the next reset pulse. If, on the other hand, the counter has counted up to the count value set at the precharge input before the next reset pulse is output, there is a thread fault. The counter then issues a signal that triggers the alarm or the machine stops.
  • the needle thread can advantageously be monitored for consumption and breakage, but in the OS it is conceded that the hook thread on a lockstitch sewing machine cannot be monitored directly but only indirectly via the needle thread due to its consumption. As a result, this thread monitor in connection with such sewing machines is unable to detect faults on Hook thread to react quickly and with sufficient sensitivity.
  • a sewing machine is known, the spool of which has a marking formed by light-dark fields on its flange facing a light source and a light receiver.
  • the marking of the rotating bobbin acts as a pulse generator.
  • the pulse sequence changes, as a result of which the switch-off mechanism of the sewing machine is actuated by electrical or electronic means arranged downstream of the light receiver.
  • thread monitors reacting to the change in the pulse sequence have the disadvantage that a reduction in the machine speed causes a bobbin advance which, despite continued thread withdrawal, can briefly trigger the bobbin stop which triggers the response of the thread monitor.
  • the invention specified in claim 1 is based on the object of designing a generic thread monitor so that it directly monitors the hook thread for a quick and sensitive display.
  • the coil is designed as a reflector for signals that are to be routed from a sensor device to a sensor serving as a receiver, neither the sensor device nor the sensor need be arranged in the immediate vicinity of the coil, which is advantageous due to the limited space in the gripper area .
  • a constant signal from the sensor device can be converted into pulses which are fed to the reset input of the counter in a sequence dependent on the thread consumption.
  • sensors can be used to monitor the coil rotation, and the monitoring can be carried out, for example, optoelectronically, magnetically, electrically or pneumatically.
  • the precharge input of the counter can be used to set the count up to which the counter sums the pulses delivered per stitch formation cycle. When this count is reached a switching process is triggered.
  • the count value should be chosen as low as possible in view of a short reaction time before the sewing machine is stopped. On the other hand, it should not be less than a minimum amount, so that a short standstill of the bobbin due to a low amount of thread does not trigger a malfunction of the thread monitor. Such a standstill is, for example, the result of a bobbin advance, which can occur due to a slight reduction in the machine speed during the sewing operation.
  • an additional counting device is advantageous according to claims 2 and 3, by which the effect of the counter of the main counting device is canceled until the maximum possible thread lot is used up.
  • the value of the at least one additional counting device can be set such that after the thread has been completely used up, the thread count is switched back to the counter of the main counting device as early as possible.
  • a counting device is sufficient, which can be adapted by switching over to the respective state of the sewing machine, such as sewing operation, stopover or thread cutting.
  • the gripper drive shown in FIG. 1 of a first embodiment contains a gripper drive shaft (1) on which a gripper body (2), which is only partially shown, is secured against rotation by a stud screw (3).
  • a bobbin case (4) is mounted in a manner not shown, which bears a central pin (5) on which a bobbin wound with thread (6) is mounted.
  • the coil (6) is provided with a front flange (7) and a rear flange (8), which are connected by a hub (9) which can be plugged onto the center pin (5).
  • the flange (7) has on its outside a marking (11) formed from light-dark fields (10).
  • the bobbin case (4) is designed with an opening (12) for the entry and exit of light signals. These are emitted by a light-emitting diode (13), which is only symbolically indicated, and, after reflection at the marking (11), are fed to a photodetector (14).
  • FIG. 3 shows in a simplified circuit diagram the elements of a control circuit (15) required for the function of the thread monitor.
  • Current flows from the positive pole of a regulated voltage source via the light-emitting diode (13) and a resistor (16) to ground.
  • Current also flows from the positive pole of the voltage source via the photodetector (14) designed as a phototransistor and a resistor (17) to ground.
  • a capacitor (18) is connected to the emitter of the photodetector (14) and is connected to an input (E1) of a counter (21) via an amplifier (19) and an AND gate (20). Together with this counter (21), the elements (17) to (20) form a counting device (22).
  • a negation element (23) is connected to the second input of the AND element (20), to which a pulse (M) emitted at its output is supplied immediately after the drive motor (24) of the sewing machine is switched on.
  • a signal corresponding to the required maximum value can be fed to it via an input (E2).
  • the maximum value can be preselected on a control panel (25) to which the input (E2) is connected.
  • a position sensor (27) which monitors the revolutions of the main shaft (26) is connected to a further input (E3) of the counter (21).
  • This has a light-emitting diode (28) connected to the positive pole of a regulated voltage source, which is connected to ground via a resistor (29) and a photodetector (30) also connected to the positive pole and designed as a phototransistor, which is connected to ground via a resistor (31) is laid on.
  • a disk (32) which is fixed on the main shaft (26) and is designed with an opening (33) for the passage of the light beams. With each pass a pulse (P) is delivered to the input (E3) of the counter (21).
  • the output (A) of the counter (21) is connected to an input of an AND gate (34). At the other inputs of the AND gate (34) are counting devices (35 to 37) connected.
  • the counting device (35) can be controlled by the pulse (M) emitted at the output of the drive motor (24), while the threading device (36) receives a pulse (F) from a thread cutting device (not shown) after thread cutting.
  • the counting device (37) can be activated by a pulse (W) in that the seamstress, after replacing the empty bobbin with a filled one, actuates a corresponding switch on the sewing machine. All three counting devices (35 to 37) are connected to the position transmitter (27) and take up the pulses (P) emitted by it.
  • the individual counting devices (35 to 37) are identical in their construction, each, as shown in FIG. 4, a dynamic element (41) formed from a resistor (38), a capacitor (39) and an amplifier (40) Has flip-flop memory (42) and a counter (43).
  • An input (ZE1) (Fig. 3 and 4) of each counter (35 to 37) is connected to the control panel (25), while at the input (ZE2) the pulses emitted by the sewing machine (M, F or W) and at the input (ZE3) the pulses (P) are recorded.
  • the output (ZA) of the respective counting device (35 to 37) is connected to an input of the AND gate (34).
  • the dynamic element (41) is connected to the input (ZE2) of the respective counting device (35 to 37) and has the effect that the received pulses (M, F or W) are only briefly applied to the input (S) of the memory (42).
  • the other input (S ') of the memory (42) is with the Output (A), the output (Q ') of the memory (42) connected to the reset input (RE) of the counter (43).
  • the output (Q ') is also connected to the output (ZA) of the counter.
  • the output of the AND gate (34) (FIG. 3) is connected to an OR gate (44), to which the counting device (37) is also connected.
  • the output of the OR gate (44) is connected via an amplifier (45) to a display element (46) which is connected to ground via a resistor (47).
  • a switch (49) which is connected to a switch-off device (48) of the drive motor (24) and which drives the main shaft (26) via a V-belt (50).
  • the first arrangement works as follows: When the sewing machine is operating, the light rays of the light-emitting diode (13) fall through the opening (12) of the bobbin case (4) onto the marking (11), are reflected on the marking and, after exiting the opening (12), are fed to the photodetector (14). If the bobbin (6) is rotated as a result of the thread draw during sewing, the light receiver (14) takes up signals of different light intensity in succession. In contrast, when the bobbin comes to a standstill as a result of thread breakage or thread end, a signal of constant light intensity is present.
  • the control circuit (15) of the exemplary embodiment only evaluates the signal when changing from a darker to a lighter field (10) of the marking (11).
  • the thread monitor would also be functional if only the transitions from a lighter to a darker field or if both transitions were evaluated.
  • the photodetector (14) With each such transition, the photodetector (14) becomes conductive and current flows through the resistor (17) to ground.
  • the voltage that builds up is fed to the AND gate (20) via the capacitor (18) and the amplifier (19).
  • the capacitor (18) is advantageously used to filter out direct currents caused by daylight and low-frequency alternating currents caused by sewing light.
  • the drive motor (24) does not emit a pulse (M) to the negation element (23), so that a signal with potential "high”, hereinafter referred to as signal (H), is present at its output.
  • signal (H) a signal with potential "high" hereinafter referred to as signal (H)
  • the counter (21) receives a signal (H) via its input (E1) and is thereby reset to its initial position, the value zero.
  • the counter (21) then begins to sum up the signals arriving at the input (E3) from the position transmitter (27), each signal corresponding to one revolution of the main shaft (26) and thus to an executed stitch.
  • the counter (21) is always reset to zero again by the respective signal received at input (E1) before the maximum value set on control panel (25) and preselected via input (E2) is reached.
  • This value can be found, for example, in that the number of stitches and thus the number of revolutions of the main shaft (26) when the bobbin is full and the smallest on the Sewing machine adjustable stitch length, which are necessary for a rotation of the bobbin (6) from one field (10) to the next, is determined by measurements.
  • the counter (21) counts up to the preselected maximum value and emits a signal (H) at its output (A) to the AND gate (34).
  • the counting devices (35 to 37), which will be discussed in greater detail below, are switched so that the signal (H) is always present at their outputs (ZA) during the sewing operation. This enables the signal (H) of the counter (21) to pass through the AND gate (34) unhindered.
  • the signal actuates the display device (46) and, when the switch (49) is closed, simultaneously the shutdown device (48) which, depending on the version, drives the drive motor (24). for example, switches off immediately or prevents it from restarting after the next stopping process.
  • the drive motor (24) When the drive motor (24) is actuated for the first time after the sewing machine has come to a standstill, for example after the bobbin (6) has been filled up, it outputs the pulse (M) to the negation element (23). As a result, the potential at the output of the negation element (23) changes briefly to "low”, hereinafter referred to as signal (L), so that signals (H) coming from the amplifier (19) and present at the AND element (20) cannot pass .
  • the pulse (M) is fed to the input (ZE2) of the counting device (35) and passes through it into the dynamic element (41).
  • the duration of the pulse (M) is limited so that it is only present for a brief moment at the input (S) of the flip-flop memory (42) and sets its output (Q) to signal (H) .
  • the AND gate (34) blocks and no signals (H) from one of the counting devices (22, 36 and 37) can interrupt the engine running.
  • the reset input (RE) of the counter (43) is connected. As soon as the signal (L) is present at this input, it is reset to zero and begins to count the revolutions of the main shaft (26) via the input (P) until it has reached the maximum value preselected via the input (ZE1). He then outputs a signal (H) to the input (S ') of the memory (42) via its output (A), which causes the signal at its output (Q') and at the output (ZA) of the counter (35) (H) is present.
  • the functioning of the counting devices (36 and 37) corresponds to that of the counting device (35).
  • the counting device (37) must be linked by the OR gate (44) to the other counting devices (22, 35 and 36), since the signal (L.) Is always at the output (ZA) of the counting device (37) during its considerably longer counting interval ) is present.
  • magnets (52) are attached to the outside of the flange (7) of the coil (6) acting as a signal transmitter (51), between which are each provided with a magnet-free field (53).
  • a receiver (54) which reacts to changes in the magnetic field is attached to the front of the bobbin case (4). This is designed as a Hall sensor (55), the connections (FIG. 7) of which are connected to the counting device (22) of the control circuit (15). Since the magnets (52) are advantageously designed as permanent magnets, a signal transmitter can be omitted.
  • the second arrangement works as follows: When the thread is drawn off from the bobbin (6), it is rotated so that the Hall sensor (55) successively records magnetic signals of different intensities. In contrast, when the bobbin comes to a standstill as a result of thread breakage or thread end, a magnetic signal of constant intensity is present. These signals are evaluated in the manner already described by the control circuit (15).
  • a receiver (56) is designed as a proximity switch (57) (FIGS. 8 to 10), which is connected to the counting device (22) via an amplifier (58).
  • the flange (7) of the coil (6) facing the proximity switch (57) and serving as a signal transmitter (59) has projections (60) on its outside.
  • the gap between the outer surface of the flange (7) and the proximity switch (57) changes continuously when the coil (6) rotates. This changes, depending on the design of the proximity switch (57), its inductance or its capacitance. These changes are evaluated in the manner already described by the control circuit (15).
  • the receiver (61) of the thread monitor is a pneumatic ring beam sensor (62) (FIGS. 11 to 14), which is shown enlarged in FIG. 13.
  • the ring jet sensor (62) has a cylindrical housing (63) with an inlet connection (64) and an annular outlet nozzle (65).
  • a tube (66) is fastened inside the housing (63), the free end of which serves as an inlet opening and the fastened end of which serves as an outflow connection (67).
  • the inflow connection (64) is connected via a pressure line (68) to a pressure source (69), the outflow connection (67) via a pressure line (70) to a pneumatic / electrical converter (71). This is connected to the counting device (22) via an amplifier (72).
  • the flange (7) of the coil (6) acting as a signal transmitter (73), is formed with projections (74) on its side facing the ring beam sensor (62).
  • the compressed air flowing in through the inlet connection (64) is deflected in the housing (63) and leaves the ring jet sensor (62) through the outlet nozzle (65). After deflection at the flange (7), the compressed air enters the pipe (66) and leaves the ring jet sensor (62) through the outflow connection (67).
  • the thread monitor according to the invention was explained in the present embodiment with reference to bobbin thread monitors.
  • the arrangement is also suitable for monitoring the needle thread in that the signal transmitter is rotatably arranged in the path of the needle thread and is driven by the latter.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Sewing Machines And Sewing (AREA)

Abstract

The control circuit (15) of a catch thread device has a counter (22) for the main shaft of the sewing machine. The counter (22) counts the number of revolutions of the main shaft (26) during the reception of one of at least two signal intensities and is reset to its initial value when this signal intensity changes to the other signal intensity. When a predetermined maximum number of revolutions is reached, the counter (22) emits a signal indicating a thread fault.

Description

Die Erfindung betrifft eine Nähmaschine nach dem Oberbegriff des Anspruches 1.The invention relates to a sewing machine according to the preamble of claim 1.

Aus der DE-OS 29 39 915 ist ein Fadenwächter für eine Nähmaschine bekannt, der einen Zähler aufweist mit einem Zähl-, einem Rückstell- und einem zur Eingabe von Zählwerten dienenden Vorladeeingang. Dem Zähleingang werden die Impulse eines bei jeder Umdrehung der Hauptwelle eine vorbestimmbare Anzahl von Impulsen erzeugenden Impulsgebers zugeleitet, während am Rückstelleingang ein durch Fadennachzug angetriebener Impulsgeber angeschlossen ist.From DE-OS 29 39 915 a thread monitor for a sewing machine is known which has a counter with a counting, a resetting and a precharging input serving for the input of counting values. The pulses of a pulse generator generating a predeterminable number of pulses each time the main shaft is rotated are fed to the counting input, while a pulse generator driven by thread retraction is connected to the reset input.

Durch jeden Impuls am Rückstelleingang wird der Zähler auf einen Ausgangswert zurückgestellt. Von diesem Wert ausgehend summiert der Zähler die Impulse am Zähleingang, bis er durch den nächsten Rückstellimpuls wieder zurückgesetzt wird. Wenn der Zähler dagegen auf den am Vorladeeingang eingestellten Zählwert hochgezählt hat, bevor der nächste Rückstellimpuls ausgegeben wird, liegt eine Fadenstörung vor. Daraufhin veranlaßt der Zähler eine Signalausgabe, die Alarm oder den Maschinenstop auslöst.Each pulse at the reset input resets the counter to an output value. Starting from this value, the counter sums the pulses at the counter input until it is reset by the next reset pulse. If, on the other hand, the counter has counted up to the count value set at the precharge input before the next reset pulse is output, there is a thread fault. The counter then issues a signal that triggers the alarm or the machine stops.

Durch einen derart ausgebildeten Fadenwächter ist der Nadelfaden zwar vorteilhaft auf Verbrauch und Bruch überwachbar, jedoch wird in der OS eingeräumt, daß der Greiferfaden an einer Doppelsteppstich-Nähmaschine nicht unmittelbar, sondern lediglich indirekt über den Nadelfaden durch dessen Verbrauch überwachbar ist. Dadurch ist dieser Fadenwächter in Verbindung mit derartigen Nähmaschinen nicht in der Lage, auf Störungen am Greiferfaden schnell und ausreichend feinfühlig zu reagieren.With a thread monitor designed in this way, the needle thread can advantageously be monitored for consumption and breakage, but in the OS it is conceded that the hook thread on a lockstitch sewing machine cannot be monitored directly but only indirectly via the needle thread due to its consumption. As a result, this thread monitor in connection with such sewing machines is unable to detect faults on Hook thread to react quickly and with sufficient sensitivity.

Aus der DE-PS 20 45 435 ist eine Nähmaschine bekannt, deren Spule an ihrem einer Lichtquelle und einem Lichtempfänger zugewendeten Flansch eine durch Hell-Dunkel-Felder gebildete Markierung aufweist. Solange Faden abgezogen wird, wirkt die Markierung der sich drehenden Spule als Impulsgeber. Bei Fadenbruch oder Fadenende ändert sich dagegen die Impulsfolge, wodurch der Abschaltmechanismus der Nähmaschine über dem Lichtempfänger nachgeordnete elektrische oder elektronische Mittel betätigt wird.From DE-PS 20 45 435 a sewing machine is known, the spool of which has a marking formed by light-dark fields on its flange facing a light source and a light receiver. As long as thread is drawn off, the marking of the rotating bobbin acts as a pulse generator. In the event of thread breakage or thread end, on the other hand, the pulse sequence changes, as a result of which the switch-off mechanism of the sewing machine is actuated by electrical or electronic means arranged downstream of the light receiver.

Auf die Änderung der Impulsfolge reagierende Fadenwächter haben infolge der Trägheit der Spule den Nachteil, daß eine Reduzierung der Maschinendrehzahl einen Spulenvorlauf bewirkt, der trotz fortgesetzten Fadenabzuges kurzzeitig einen das Ansprechen des Fadenwächters auslösenden Spulenstillstand bewirken kann.Due to the inertia of the bobbin, thread monitors reacting to the change in the pulse sequence have the disadvantage that a reduction in the machine speed causes a bobbin advance which, despite continued thread withdrawal, can briefly trigger the bobbin stop which triggers the response of the thread monitor.

Aus der US-PS 37 38 296 ist eine Spule bekannt, die eine Reflexionsfläche aufweist. Die an dieser umgelenkten Lichtstrahlen eines Vorratswächters werden als Lichtsignale einem Zähler einer externen Steuerschaltung zugeführt. Die während des Nähens erfolgende Anzahl von Spulenumdrehungen wird in dem Zähler summiert und dieser Istwert mit einem vorgewählten Sollwert verglichen. Bei Übereinstimmung der beiden Werte wird die Nähmaschine stillgesetzt.From US-PS 37 38 296 a coil is known which has a reflective surface. The light rays deflected by a supply monitor are fed to a counter of an external control circuit as light signals. The number of bobbin revolutions that take place during sewing is summed in the counter and this actual value is compared with a preselected setpoint. If the two values match, the sewing machine is stopped.

Die in der US-PS beschriebene Anordnung ermöglicht zwar, die Restfadenmenge dem Bedarf entsprechend vorzuwählen, ein Bruch des Spulenfadens wird jedoch nicht angezeigt.The arrangement described in the US-PS allows the amount of remaining thread to be selected as required, but a break in the bobbin thread is not indicated.

Der im Anspruch 1 angegebenen Erfindung liegt die Aufgabe zugrunde, einen gattungsgemäßen Fadenwächter so auszubilden, daß dieser für eine schnelle und feinfühlige Anzeige den Greiferfaden direkt überwacht.The invention specified in claim 1 is based on the object of designing a generic thread monitor so that it directly monitors the hook thread for a quick and sensitive display.

Diese Aufgabe wird bei dem erfindungsgemäßen Fadenwächter durch die kennzeichnenden Merkmale des Anspruches 1 gelöst.This object is achieved in the thread monitor according to the invention by the characterizing features of claim 1.

Da die Spule als Reflektor für Signale, die von einer Sensorvorrichtung zu einem als Empfänger dienenden Sensor geleitet werden sollen, ausgebildet ist, müssen weder die Sensorvorrichtung noch der Sensor in unmittelbarer Nähe der Spule angeordnet sein, was aufgrund des begrenzten Raumes im Greiferbereich von Vorteil ist.Since the coil is designed as a reflector for signals that are to be routed from a sensor device to a sensor serving as a receiver, neither the sensor device nor the sensor need be arranged in the immediate vicinity of the coil, which is advantageous due to the limited space in the gripper area .

Durch das unterschiedliche Reflexionsverhalten der Reflexionsflächen der Spule ist ein konstantes Signal der Sensorvorrichtung in Impulse umformbar, die dem Rückstelleingang des Zählers mit einer vom Fadenverbrauch abhängigen Folge zugeleitet werden.Due to the different reflection behavior of the reflection surfaces of the bobbin, a constant signal from the sensor device can be converted into pulses which are fed to the reset input of the counter in a sequence dependent on the thread consumption.

Aufgrund dieser Wirkungsweise der Spule ist ein separater, durch Fadennachzug angetriebener Impulsgeber, nicht erforderlich. Dadurch vereinfacht sich der nachträgliche Einbau des Fadenwächters in eine Nähmaschine beträchtlich.Due to this mode of action of the bobbin, a separate pulse generator driven by thread retraction is not required. This considerably simplifies the subsequent installation of the thread monitor in a sewing machine.

Zum Überwachen der Spulendrehung sind verschiedenartige Sensoren verwendbar, wobei die Überwachung beispielsweise optoelektronisch, magnetisch, elektrisch oder pneumatisch erfolgen kann.Various types of sensors can be used to monitor the coil rotation, and the monitoring can be carried out, for example, optoelectronically, magnetically, electrically or pneumatically.

Über den Vorladeeingang des Zählers ist einstellbar, bis zu welchem Zählwert dieser die pro Stichbildezyklus gelieferten Impulse summiert. Bei Erreichen dieses Zählwertes wird ein Schaltvorgang ausgelöst.The precharge input of the counter can be used to set the count up to which the counter sums the pulses delivered per stitch formation cycle. When this count is reached a switching process is triggered.

Der Zählwert ist im Hinblick auf eine geringe Reaktionszeit bis zum Stillsetzen der Nähmaschine möglichst niedrig zu wählen. Andererseits sollte er einen minimalen Betrag nicht unterschreiten, damit ein kurzzeitiger Stillstand der Spule aufgrund einer geringen Fadenlose keine Fehlfunktion des Fadenwächters auslöst. Ein derartiger Stillstand ist beispielsweise die Folge eines Spulenvorlaufes, der durch eine geringfügige Reduzierung der Maschinendrehzahl während des Nähbetriebes auftreten kann.The count value should be chosen as low as possible in view of a short reaction time before the sewing machine is stopped. On the other hand, it should not be less than a minimum amount, so that a short standstill of the bobbin due to a low amount of thread does not trigger a malfunction of the thread monitor. Such a standstill is, for example, the result of a bobbin advance, which can occur due to a slight reduction in the machine speed during the sewing operation.

Bei einer relativ großen Fadenlosen nach einem Zwischenstop, insbesondere nach Abbremsen der Nähmaschine von Maximaldrehzahl auf Stillstand, ist gemäß Anspruch 2 und 3 eine Zusatz-Zähleinrichtung von Vorteil, durch welche die Wirkung des Zählers der Haupt-Zähleinrichtung aufgehoben wird, bis die maximal mögliche Fadenlose aufgebraucht ist.In the case of a relatively large thread lot after an intermediate stop, in particular after braking the sewing machine from maximum speed to standstill, an additional counting device is advantageous according to claims 2 and 3, by which the effect of the counter of the main counting device is canceled until the maximum possible thread lot is used up.

Beim Fadenschneiden wird eine relativ große Fadenmenge nachgezogen. Beim Wiederanlauf muß diese Fadenlose zuerst verarbeitet werden, bevor durch erneuten Fadennachzug die Spule in Drehung versetzt wird. Deshalb ist nach Anspruch 4 eine weitere Zusatz-Zähleinrichtung vorgesehen, durch welche der Zähler der Haupt-Zähleinrichtung erst nach vollständigem Verbrauch dieser Fadenlose wieder zugeschaltet wird.A relatively large amount of thread is drawn during thread cutting. When restarting, this thread lot must first be processed before the bobbin is set in rotation by a new thread pull. Therefore, according to claim 4, a further additional counting device is provided, by means of which the counter of the main counting device is only switched on again after these thread lots have been completely used up.

Durch die Maßnahme nach Anspruch 5 ist der Wert der wenigstens einen Zusatz-Zähleinrichtung so einstellbar, daß nach vollständigem Verbrauch der Fadenlose so früh als möglich auf den Zähler der Haupt-Zähleinrichtung zurückgeschaltet wird.Through the measure according to claim 5, the value of the at least one additional counting device can be set such that after the thread has been completely used up, the thread count is switched back to the counter of the main counting device as early as possible.

Durch die Maßnahme nach Anspruch 6 genügt eine Zähleinrichtung, die durch Umschalten dem jeweiligen Zustand der Nähmaschine, wie Nähbetrieb, Zwischenstop oder Fadenschneiden anpaßbar ist.By the measure according to claim 6, a counting device is sufficient, which can be adapted by switching over to the respective state of the sewing machine, such as sewing operation, stopover or thread cutting.

Die Erfindung ist anhand eines in der Zeichnung dargestellten Ausführungsbeispieles erläutert. Es zeigt:

  • Fig. 1 einen Schnitt durch den Greifer einer Nähmaschine;
  • Fig. 2 einen Schnitt nach der Linie II-II der Fig. 1;
  • Fig. 3 einen vereinfachten Schaltplan;
  • Fig. 4 den Aufbau einer Zähleinrichtung;
  • Fig. 5 einen Schnitt durch einen Greifer nach der Linie V-V der Fig. 6;
  • Fig. 6 einen Schnitt nach der Linie VI-VI der Fig. 5;
  • Fig. 7 die dem Sensor der Fig. 5 zugeordnete Zähleinrichtung;
  • Fig. 8 einen Schnitt durch den Greifer nach der Linie VIII-VIII der Fig. 9;
  • Fig. 9 einen Schnitt nach der Linie IX-IX der Fig. 8;
  • Fig. 10 die dem Sensor der Fig. 8 zugeordnete Zähleinrichtung;
  • Fig. 11 einen Schnitt durch den Greifer nach der Linie XI-XI der Fig. 12;
  • Fig. 12 einen Schnitt nach der Linie XII-XII der Fig. 11;
  • Fig. 13 eine vergrößerte Schnittdarstellung des Sensors der Fig. 11;
  • Fig. 14 die dem Sensor der Fig. 11 zugeordnete Zähleinrichtung.
The invention is explained with reference to an embodiment shown in the drawing. It shows:
  • 1 shows a section through the gripper of a sewing machine.
  • Fig. 2 is a section along the line II-II of Fig. 1;
  • 3 shows a simplified circuit diagram;
  • 4 shows the construction of a counting device;
  • 5 shows a section through a gripper along the line VV of FIG. 6.
  • Fig. 6 is a section along the line VI-VI of Fig. 5;
  • 7 shows the counting device assigned to the sensor of FIG. 5;
  • 8 shows a section through the gripper along the line VIII-VIII of FIG. 9.
  • Fig. 9 is a section along the line IX-IX of Fig. 8;
  • 10 shows the counting device assigned to the sensor of FIG. 8;
  • 11 shows a section through the gripper along the line XI-XI of FIG. 12;
  • Fig. 12 is a section along the line XII-XII of Fig. 11;
  • 13 is an enlarged sectional view of the sensor of FIG. 11;
  • FIG. 14 the counting device assigned to the sensor of FIG. 11.

Der in Fig. 1 dargestellte Greiferantrieb eines ersten Ausführungsbeispieles enthält eine Greiferantriebswelle (1), auf der ein nur teilweise dargestellter Greiferkörper (2) durch eine Stiftschraube (3) verdrehsicher befestigt ist.The gripper drive shown in FIG. 1 of a first embodiment contains a gripper drive shaft (1) on which a gripper body (2), which is only partially shown, is secured against rotation by a stud screw (3).

Im Greiferkörper (2) ist in nicht dargestellter Weise eine Spulenkapsel (4) gelagert, die einen Mittenzapfen (5) trägt, auf dem eine mit Faden bewickelte Spule (6) gelagert ist. Die Spule (6) ist mit einem vorderen Flansch (7) und einem hinteren Flansch (8) versehen, welche durch eine auf den Mittenzapfen (5) steckbare Nabe (9) verbunden sind. Der Flansch (7) weist an seiner Außenseite eine aus Hell-Dunkel-Feldern (10) gebildete Markierung (11) auf.In the gripper body (2), a bobbin case (4) is mounted in a manner not shown, which bears a central pin (5) on which a bobbin wound with thread (6) is mounted. The coil (6) is provided with a front flange (7) and a rear flange (8), which are connected by a hub (9) which can be plugged onto the center pin (5). The flange (7) has on its outside a marking (11) formed from light-dark fields (10).

Die Spulenkapsel (4) ist mit einer Öffnung (12) zum Ein- und Austritt von Lichtsignalen ausgebildet. Diese werden von einer nur symbolhaft angedeuteten Leuchtdiode (13) abgestrahlt und nach Reflexion an der Markierung (11) einem Fotodetektor (14) zugeleitet.The bobbin case (4) is designed with an opening (12) for the entry and exit of light signals. These are emitted by a light-emitting diode (13), which is only symbolically indicated, and, after reflection at the marking (11), are fed to a photodetector (14).

Die Fig. 3 zeigt in einem vereinfachten Schaltplan die zur Funktion des Fadenwächters erforderlichen Elemente einer Steuerschaltung (15). Vom Pluspol einer geregelten Spannungsquelle fließt Strom über die Leuchtdiode (13) und einen Widerstand (16) an Masse. Ebenso fließt Strom vom Pluspol der Spannungsquelle über den als Fototransistor ausgebildeten Fotodetektor (14) und einen Widerstand (17) an Masse.3 shows in a simplified circuit diagram the elements of a control circuit (15) required for the function of the thread monitor. Current flows from the positive pole of a regulated voltage source via the light-emitting diode (13) and a resistor (16) to ground. Current also flows from the positive pole of the voltage source via the photodetector (14) designed as a phototransistor and a resistor (17) to ground.

Mit dem Emitter des Fotodetektors (14) ist ein Kondensator (18) verbunden, der über einen Verstärker (19) und ein UND-Glied (20) an einen Eingang (E1) eines Zählers (21) angeschlossen ist. Zusammen mit diesem Zähler (21) bilden die Elemente (17) bis (20) eine Zähleinrichtung (22).A capacitor (18) is connected to the emitter of the photodetector (14) and is connected to an input (E1) of a counter (21) via an amplifier (19) and an AND gate (20). Together with this counter (21), the elements (17) to (20) form a counting device (22).

An dem zweiten Eingang des UND-Gliedes (20) ist ein Negationsglied (23) angeschlossen, dem unmittelbar nach Einschalten des Antriebsmotors (24) der Nähmaschine ein an dessen Ausgang abgegebener Impuls (M) zugeführt wird.A negation element (23) is connected to the second input of the AND element (20), to which a pulse (M) emitted at its output is supplied immediately after the drive motor (24) of the sewing machine is switched on.

Zum Einstellen des Zählers (21) ist diesem über einen Eingang (E2) ein dem erforderlichen Maximalwert entsprechendes Signal zuführbar. Der Maximalwert kann an einem Steuerpult (25), mit dem der Eingang (E2) verbunden ist, vorgewählt werden. An einen weiteren Eingang (E3) des Zählers (21) ist ein die Umdrehungen der Hauptwelle (26) überwachender Positionsgeber (27) angeschlossen. Dieser weist eine an den Pluspol einer geregelten Spannungsquelle angeschlossene Leuchtdiode (28), die über einen Widerstand (29) an Masse gelegt ist und einen ebenfalls am Pluspol angeschlossenen, als Fototransistor ausgebildeten Fotodetektor (30), der über ein Widerstand (31) an Masse gelegt ist, auf. Im Lichtweg zwischen Leuchtdiode (28) und Fotodetektor (30) ist eine drehfest auf der Hauptwelle (26) angebrachte Scheibe (32) vorgesehen, die mit einer Öffnung (33) zum Durchgang der Lichtstrahlen ausgebildet ist. Bei jedem Durchgang wird ein Impuls (P) an den Eingang (E3) des Zählers (21) abgegeben.To set the counter (21), a signal corresponding to the required maximum value can be fed to it via an input (E2). The maximum value can be preselected on a control panel (25) to which the input (E2) is connected. A position sensor (27) which monitors the revolutions of the main shaft (26) is connected to a further input (E3) of the counter (21). This has a light-emitting diode (28) connected to the positive pole of a regulated voltage source, which is connected to ground via a resistor (29) and a photodetector (30) also connected to the positive pole and designed as a phototransistor, which is connected to ground via a resistor (31) is laid on. Provided in the light path between the light-emitting diode (28) and the photodetector (30) is a disk (32) which is fixed on the main shaft (26) and is designed with an opening (33) for the passage of the light beams. With each pass a pulse (P) is delivered to the input (E3) of the counter (21).

Der Ausgang (A) des Zählers (21) ist mit einem Eingang eines UND-Gliedes (34) verbunden. An den anderen Eingängen des UND-Gliedes (34) sind Zähleinrichtungen (35 bis 37) angeschlossen.The output (A) of the counter (21) is connected to an input of an AND gate (34). At the other inputs of the AND gate (34) are counting devices (35 to 37) connected.

Die Zähleinrichtung (35) ist nach jedem Zwischenstop der Nähmaschine durch den am Ausgang des Antriebsmotors (24) abgegebenen Impuls (M) ansteuerbar, während die Zähleinrichtung (36) nach Fadenschneiden einen Impuls (F) von einer nicht dargestellten Fadenschneideinrichtung erhält. Die Zähleinrichtung (37) ist dagegen durch einen Impuls (W) aktivierbar, indem die Näherin nach Austausch der leeren Spule gegen eine gefüllte einen entsprechenden Schalter an der Nähmaschine betätigt. Alle drei Zähleinricntungen (35 bis 37) sind an den Positionsgeber (27) angeschlossen und nehmen die von diesem abgegebenen Impulse (P) auf.After each stop of the sewing machine, the counting device (35) can be controlled by the pulse (M) emitted at the output of the drive motor (24), while the threading device (36) receives a pulse (F) from a thread cutting device (not shown) after thread cutting. The counting device (37), on the other hand, can be activated by a pulse (W) in that the seamstress, after replacing the empty bobbin with a filled one, actuates a corresponding switch on the sewing machine. All three counting devices (35 to 37) are connected to the position transmitter (27) and take up the pulses (P) emitted by it.

Die einzelnen Zähleinrichtungen (35 bis 37) sind in ihrem Aufbau identisch, wobei jede, wie in Fig. 4 dargestellt, ein aus einem Widerstand (38), einem Kondensator (39) und einem Verstärker (40) gebildetes Dynamikglied (41), einen Flip-Flop-Speicher (42) und einen Zähler (43) aufweist.The individual counting devices (35 to 37) are identical in their construction, each, as shown in FIG. 4, a dynamic element (41) formed from a resistor (38), a capacitor (39) and an amplifier (40) Has flip-flop memory (42) and a counter (43).

Ein Eingang (ZE1) (Fig. 3 und 4) jeder Zähleinrichtung (35 bis 37) ist an dem Steuerpult (25) angeschlossen, während am Eingang (ZE2) die von der Nähmaschine abgegebenen Impulse (M, F oder W) und am Eingang (ZE3) die Impulse (P) aufgenommen werden. Der Ausgang (ZA) der jeweiligen Zähleinrichtung (35 bis 37) ist mit je einem Eingang des UND-Gliedes (34) verbunden.An input (ZE1) (Fig. 3 and 4) of each counter (35 to 37) is connected to the control panel (25), while at the input (ZE2) the pulses emitted by the sewing machine (M, F or W) and at the input (ZE3) the pulses (P) are recorded. The output (ZA) of the respective counting device (35 to 37) is connected to an input of the AND gate (34).

Das Dynamikglied (41) ist an den Eingang (ZE2) der jeweiligen Zähleinrichtung (35 bis 37) angeschlossen und bewirkt, daß die aufgenommenen Impulse (M,F oder W) nur kurzzeitig am Eingang (S) des Speichers (42) anliegen. Der andere Eingang (S′) des Speichers (42) ist mit dem Ausgang (A), der Ausgang (Q′) des Speichers (42) mit dem Rücksetzeingang (RE) des Zählers (43) verbunden. Der Ausgang (Q′) ist außerdem an den Ausgang (ZA) der Zähleinrichtung angeschlossen.The dynamic element (41) is connected to the input (ZE2) of the respective counting device (35 to 37) and has the effect that the received pulses (M, F or W) are only briefly applied to the input (S) of the memory (42). The other input (S ') of the memory (42) is with the Output (A), the output (Q ') of the memory (42) connected to the reset input (RE) of the counter (43). The output (Q ') is also connected to the output (ZA) of the counter.

Der Ausgang des UND-Gliedes (34) (Fig. 3) ist mit einem ODER-Glied (44) verbunden, an dem auch die Zähleinrichtung (37) angeschlossen ist. Der Ausgang des ODER-Gliedes (44) ist über einen Verstärker (45) mit einem Anzeigeelement (46) verbunden, das über einen Widerstand (47) an Masse angeschlossen ist. Am Ausgang des Verstärkers (45) ist außerdem ein mit einer Abschaltvorrichtung (48) des Antriebsmotors (24) verbundener Schalter (49) angeschlossen, der die Hauptwelle (26) über einen Keilriemen (50) antreibt.The output of the AND gate (34) (FIG. 3) is connected to an OR gate (44), to which the counting device (37) is also connected. The output of the OR gate (44) is connected via an amplifier (45) to a display element (46) which is connected to ground via a resistor (47). At the output of the amplifier (45) there is also connected a switch (49) which is connected to a switch-off device (48) of the drive motor (24) and which drives the main shaft (26) via a V-belt (50).

Die erste Anordnung arbeitet wie folgt:
   Beim Betrieb der Nähmaschine fallen die Lichtstrahlen der Leuchtdiode (13) durch die Öffnung (12) der Spulenkapsel (4) auf die Markierung (11), werden an dieser reflektiert und nach Wiederaustritt aus der Öffnung (12) dem Fotodetektor (14) zugeleitet. Wenn dabei die Spule (6) infolge des Fadenabzuges beim Nähbetrieb gedreht wird, nimmt der Lichtempfänger (14) nacheinander Signale unterschiedlicher Lichtintensität auf. Bei Spulenstillstand infolge von Fadenbruch oder Fadenende liegt dagegen ein Signal konstanter Lichtintensität an.The first arrangement works as follows:
When the sewing machine is operating, the light rays of the light-emitting diode (13) fall through the opening (12) of the bobbin case (4) onto the marking (11), are reflected on the marking and, after exiting the opening (12), are fed to the photodetector (14). If the bobbin (6) is rotated as a result of the thread draw during sewing, the light receiver (14) takes up signals of different light intensity in succession. In contrast, when the bobbin comes to a standstill as a result of thread breakage or thread end, a signal of constant light intensity is present.

Durch die Steuerschaltung (15) des Ausführungsbeispieles wird jeweils nur das Signal beim Übergang von einem dunkleren auf ein hellers Feld (10) der Markierung (11) ausgewertet. Der Fadenwächter wäre jedoch ebenso funktionsfähig, wenn ausschließlich die Übergänge von einem helleren auf ein dunkleres Feld bzw. wenn beide Übergänge ausgewertet würden.The control circuit (15) of the exemplary embodiment only evaluates the signal when changing from a darker to a lighter field (10) of the marking (11). However, the thread monitor would also be functional if only the transitions from a lighter to a darker field or if both transitions were evaluated.

Bei jedem derartigen Übergang wird der Fotodetektor (14) leitend und es fließt Strom über den Widerstand (17) an Masse.With each such transition, the photodetector (14) becomes conductive and current flows through the resistor (17) to ground.

Die sich dabei aufbauende Spannung wird über den Kondensator (18) und den Verstärker (19) dem UND-Glied (20) zugeführt. Der Kondensator (18) dient dabei vorteilhafterweise zum Ausfiltern von durch Tageslicht verursachten Gleichströmen und von durch Nählicht verursachten Wechselströmen niedriger Frequenz.The voltage that builds up is fed to the AND gate (20) via the capacitor (18) and the amplifier (19). The capacitor (18) is advantageously used to filter out direct currents caused by daylight and low-frequency alternating currents caused by sewing light.

Während des Nähens gibt der Antriebsmotor (24) keinen Impuls (M) an das Negationsglied (23) ab, so daß an dessen Ausgang ein Signal mit Potential "high", im folgenden als Signal (H) bezeichnet, anliegt. Sobald auch am Ausgang des Verstärkers (19) ein derartiges Signal abgegeben wird, nimmt der Zähler (21) über seinen Eingang (E1) ein Signal (H) auf und wird dadurch in seine Ausgangsstellung, den Wert Null zurückgesetzt. Der Zähler (21) beginnt daraufhin, die am Eingang (E3) vom Positionsgeber (27) eintreffenden Signale zu summieren, wobei jedes Signal einer Umdrehung der Hauptwelle (26) und somit einem ausgeführten Stich entspricht. Solange sich die Spule dreht, wird der Zähler (21) stets erneut durch das jeweilige, am Eingang (E1) aufgenommene Signal auf null zurückgesetzt, bevor der am Steuerpult (25) eingestellte und über den Eingang (E2) vorgewählte Maximalwert erreicht wird. Dieser Wert kann beispielweise dadurch gefunden werden, daß die Anzahl der Stiche und damit die Anzahl der Umdrehungen der Hauptwelle (26) bei voller Spule und kleinster an der Nähmaschine einstellbarer Stichlänge, die für eine Drehung der Spule (6) von einem Feld (10) auf das nächste notwendig sind, durch Messungen ermittelt wird.During sewing, the drive motor (24) does not emit a pulse (M) to the negation element (23), so that a signal with potential "high", hereinafter referred to as signal (H), is present at its output. As soon as such a signal is also emitted at the output of the amplifier (19), the counter (21) receives a signal (H) via its input (E1) and is thereby reset to its initial position, the value zero. The counter (21) then begins to sum up the signals arriving at the input (E3) from the position transmitter (27), each signal corresponding to one revolution of the main shaft (26) and thus to an executed stitch. As long as the coil is rotating, the counter (21) is always reset to zero again by the respective signal received at input (E1) before the maximum value set on control panel (25) and preselected via input (E2) is reached. This value can be found, for example, in that the number of stitches and thus the number of revolutions of the main shaft (26) when the bobbin is full and the smallest on the Sewing machine adjustable stitch length, which are necessary for a rotation of the bobbin (6) from one field (10) to the next, is determined by measurements.

Wenn die Spule (6) infolge einer Fadenstörung stillsteht, so zählt der Zähler (21) bis auf den vorgewählten Maximalwert hoch und gibt ein Signal (H) an seinem Ausgang (A) an das UND-Glied (34) ab. Die Zähleinrichtungen (35 bis 37), auf die nachfolgend noch ausführlicher eingegangen wird, sind so geschaltet, daß an ihren Ausgängen (ZA) während des Nähbetriebes stets das Signal (H) anliegt. Dadurch kann das Signal (H) des Zählers (21) das UND-Glied (34) ungehindert passieren. Nach anschließendem Durchgang durch das ODER-Glied (44) und durch den Verstärker (45) betätigt das Signal die Anzeigeeinrichtung (46) und bei geschlossenem Schalter (49) auch gleichzeitig die Abschaltvorrichtung (48), die je nach Ausführung den Antriebsmotor (24) beispielsweise sofort abschaltet oder aber dessen Wiederanlauf nach dem nächsten Anhaltevorgang verhindert.If the bobbin (6) stops due to a thread fault, the counter (21) counts up to the preselected maximum value and emits a signal (H) at its output (A) to the AND gate (34). The counting devices (35 to 37), which will be discussed in greater detail below, are switched so that the signal (H) is always present at their outputs (ZA) during the sewing operation. This enables the signal (H) of the counter (21) to pass through the AND gate (34) unhindered. After subsequent passage through the OR gate (44) and through the amplifier (45), the signal actuates the display device (46) and, when the switch (49) is closed, simultaneously the shutdown device (48) which, depending on the version, drives the drive motor (24). for example, switches off immediately or prevents it from restarting after the next stopping process.

Wenn nach einem Stillstand der Nähmaschine, beispielsweise nach Auffüllen der Spule (6) der Antriebsmotor (24) erstmalig betätigt wird, gibt dieser den Impuls (M) an das Negationsglied (23) ab. Dadurch wechselt das Potential am Ausgang des Negationsgliedes (23) kurzzeitig auf "low", im folgenden kurz Signal (L) genannt, so daß am UND-Glied (20) anliegende, vom Verstärker (19) kommende Signale (H) nicht passieren können.When the drive motor (24) is actuated for the first time after the sewing machine has come to a standstill, for example after the bobbin (6) has been filled up, it outputs the pulse (M) to the negation element (23). As a result, the potential at the output of the negation element (23) changes briefly to "low", hereinafter referred to as signal (L), so that signals (H) coming from the amplifier (19) and present at the AND element (20) cannot pass .

Gleichzeitig wird der Impuls (M) dem Eingang (ZE2) der Zähleinrichtung (35) zugeleitet und gelangt über diesen in das Dynamikglied (41). Durch dessen als Zeitglied wirkenden Kondensator (39) wird die Dauer des Impulses (M) begrenzt, so daß dieser nur für einen kurzen Moment am Eingang (S) des Flip-Flop-Speichers (42) anliegt und dessen Ausgang (Q) auf signal (H) setzt.At the same time, the pulse (M) is fed to the input (ZE2) of the counting device (35) and passes through it into the dynamic element (41). Through that as a timer acting capacitor (39) the duration of the pulse (M) is limited so that it is only present for a brief moment at the input (S) of the flip-flop memory (42) and sets its output (Q) to signal (H) .

An dem mit dem Ausgang (Q′) des Speichers (42) verbundenen Ausgang (ZA) der Zähleinrichtung (35) liegt dadurch das Signal (L) an, so daß das UND-Glied (34) sperrt und keine Signale (H) von einer der Zähleinrichtungen (22, 36 und 37) den Motorlauf unterbrechen können.At the output (Q ') of the memory (42) connected to the output (ZA) of the counter (35), the signal (L) is present, so that the AND gate (34) blocks and no signals (H) from one of the counting devices (22, 36 and 37) can interrupt the engine running.

An den Ausgang (Q′) des Speichers (42) ist auch der Rücksetzeingang (RE) des Zählers (43) angeschlossen. Sobald an diesem Eingang das Signal (L) anliegt, wird dieser auf Null zurückgesetzt und beginnt über den Eingang (P) die Umdrehungen der Hauptwelle (26) zu zählen, bis er den über den Eingang (ZE1) vorgewählten Maximalwert erreicht hat. Er gibt daraufhin über seinen Ausgang (A) ein Signal (H) an den Eingang (S′) des Speichers (42) ab, wodurch an dessen Ausgang (Q′) sowie am Ausgang (ZA) der Zähleinrichtung (35) wieder das Signal (H) anliegt.At the output (Q ') of the memory (42), the reset input (RE) of the counter (43) is connected. As soon as the signal (L) is present at this input, it is reset to zero and begins to count the revolutions of the main shaft (26) via the input (P) until it has reached the maximum value preselected via the input (ZE1). He then outputs a signal (H) to the input (S ') of the memory (42) via its output (A), which causes the signal at its output (Q') and at the output (ZA) of the counter (35) (H) is present.

Die Funktionsweise der Zähleinrichtungen (36 und 37) entspricht der der Zähleinrichtung (35). Die Zähleinrichtung (37) ist jedoch durch das ODER-Glied (44) mit den übrigen Zähleinrichtungen (22, 35 und 36) zu verknüpfen, da am Ausgang (ZA) der Zähleinrichtung (37) während ihres erheblich längeren Zählintervalles stets das Signal (L) anliegt.The functioning of the counting devices (36 and 37) corresponds to that of the counting device (35). However, the counting device (37) must be linked by the OR gate (44) to the other counting devices (22, 35 and 36), since the signal (L.) Is always at the output (ZA) of the counting device (37) during its considerably longer counting interval ) is present.

Bei einem zweiten Ausführungsbeispiel sind an der Außenseite des als Signalgeber (51) wirkenden Flansches (7) der Spule (6) Magnete (52) angebracht, zwischen denen jeweils ein magnetfreies Feld (53) vorgesehen ist. An der Vorderseite der Spulenkapsel (4) ist ein auf Magnetfeldänderungen reagierender Empfänger (54) angebracht. Dieser ist als Hallsensor (55) ausgebildet, dessen Anschlüsse (Fig. 7) mit der Zähleinrichtung (22) der Steuerschaltung (15) verbunden sind. Da die Magnete (52) vorteilhafterweise als Dauermagnete ausgeführt sind, kann ein Signalsender entfallen.In a second exemplary embodiment, magnets (52) are attached to the outside of the flange (7) of the coil (6) acting as a signal transmitter (51), between which are each provided with a magnet-free field (53). A receiver (54) which reacts to changes in the magnetic field is attached to the front of the bobbin case (4). This is designed as a Hall sensor (55), the connections (FIG. 7) of which are connected to the counting device (22) of the control circuit (15). Since the magnets (52) are advantageously designed as permanent magnets, a signal transmitter can be omitted.

Die zweite Anordnung arbeitet wie folgt:
   Beim Fadenabzug von der Spule (6) wird diese gedreht, so daß der Hallsensor (55) nacheinander magnetische Signale unterschiedlicher Intensität aufnimmt. Bei Spulenstillstand infolge von Fadenbruch oder Fadenende liegt dagegen ein magnetisches Signal konstanter Intensität an. Die Auswertung dieser Signale erfolgt in der bereits beschriebenen Weise durch die Steuerschaltung (15).The second arrangement works as follows:
When the thread is drawn off from the bobbin (6), it is rotated so that the Hall sensor (55) successively records magnetic signals of different intensities. In contrast, when the bobbin comes to a standstill as a result of thread breakage or thread end, a magnetic signal of constant intensity is present. These signals are evaluated in the manner already described by the control circuit (15).

Bei einem dritten Ausführungsbeispiel ist ein Empfänger (56) als Näherungsschalter (57) (Fig. 8 bis 10) ausgebildet, der über einen Verstärker (58) an die Zähleinrichtung (22) angeschlossen ist. Der dem Näherungsschalter (57) zugewendete, als Signalgeber (59) dienende Flansch (7) der Spule (6) weist an seiner Außenseite Vorsprünge (60) auf.In a third exemplary embodiment, a receiver (56) is designed as a proximity switch (57) (FIGS. 8 to 10), which is connected to the counting device (22) via an amplifier (58). The flange (7) of the coil (6) facing the proximity switch (57) and serving as a signal transmitter (59) has projections (60) on its outside.

Bedingt durch die Vorsprünge (60) ändert sich bei Drehung der Spule (6) ständig der Zwischenraum zwischen der Außenfläche des Flansches (7) und dem Näherungsschalter (57). Dadurch ändert sich, je nach Ausführung des Näherungsschalters (57), dessen Induktivität oder dessen Kapazität. Die Auswertung dieser Änderungen erfolgt in bereits beschriebener Weise durch die Steuerschaltung (15).Due to the projections (60), the gap between the outer surface of the flange (7) and the proximity switch (57) changes continuously when the coil (6) rotates. This changes, depending on the design of the proximity switch (57), its inductance or its capacitance. These changes are evaluated in the manner already described by the control circuit (15).

Bei einem weiteren Ausführungsbeispiel ist der Empfänger (61) des Fadenwächters ein pneumatischer Ringstrahlsensor (62) (Fig. 11 bis 14), der in Fig. 13 vergrößert abgebildet ist. Der Ringstrahlsensor (62) weist ein zylindrisches Gehäuse (63) mit Zustromanschluß (64) und ringförmiger Auslaßdüse (65) auf. Im Inneren des Gehäuses (63) ist ein Rohr (66) befestigt, dessen freies Ende als Einlaßöffnung und dessen befestigtes Ende als Abstromanschluß (67) dient. Der Zustromanschluß (64) ist über eine Druckleitung (68) mit einer Druckquelle (69), der Abstromanschluß (67) über eine Druckleitung (70) mit einem pneumatisch/elektrischen Umformer (71) verbunden. Dieser ist über einen Verstärker (72) an die Zähleinrichtung (22) angeschlossen.In a further exemplary embodiment, the receiver (61) of the thread monitor is a pneumatic ring beam sensor (62) (FIGS. 11 to 14), which is shown enlarged in FIG. 13. The ring jet sensor (62) has a cylindrical housing (63) with an inlet connection (64) and an annular outlet nozzle (65). A tube (66) is fastened inside the housing (63), the free end of which serves as an inlet opening and the fastened end of which serves as an outflow connection (67). The inflow connection (64) is connected via a pressure line (68) to a pressure source (69), the outflow connection (67) via a pressure line (70) to a pneumatic / electrical converter (71). This is connected to the counting device (22) via an amplifier (72).

Der Flansch (7) der Spule (6) ist, als Signalgeber (73) wirkend, an seiner dem Ringstrahlsensor (62) zugewendeten Seite mit Vorsprüngen (74) ausgebildet.The flange (7) of the coil (6), acting as a signal transmitter (73), is formed with projections (74) on its side facing the ring beam sensor (62).

Die durch den Zustromanschluß (64) einströmende Druckluft wird im Gehäuse (63) umgelenkt und verläßt den Ringstrahlsensor (62) durch die Auslaßdüse (65). Nach Umlenkung an dem Flansch (7) tritt die Druckluft in das Rohr (66) ein und verläßt den Ringstrahlsensor (62) durch den Abstromanschluß (67).The compressed air flowing in through the inlet connection (64) is deflected in the housing (63) and leaves the ring jet sensor (62) through the outlet nozzle (65). After deflection at the flange (7), the compressed air enters the pipe (66) and leaves the ring jet sensor (62) through the outflow connection (67).

Die Drehung der Spule (6) infolge von Fadenabzug bewirkt Druckänderungen im Rohr (66) aufgrund der Abstandsänderungen zwischen dem Ringstrahlsensor (62) und dem Flansch (7). Diese Druckänderungen werden an den Umformer (71) weitergeleitet, der sie zur Auswertung in der Steuerschaltung (15) entsprechend umformt.The rotation of the bobbin (6) as a result of thread withdrawal causes pressure changes in the tube (66) due to the changes in distance between the ring beam sensor (62) and the flange (7). These pressure changes are passed on to the converter (71), which converts them accordingly for evaluation in the control circuit (15).

Die Funktionsweise des erfindungsgemäßen Fadenwächters wurde im vorliegenden Ausführungsbeispiel anhand von Spulenfadenwächtern erläutert. Die Anordnung ist jedoch ebenso zur Überwachung des Nadelfadens geeignet, indem der Signalgeber im Weg des Nadelfadens drehbar angeordnet und durch diesen angetrieben ist.The operation of the thread monitor according to the invention was explained in the present embodiment with reference to bobbin thread monitors. However, the arrangement is also suitable for monitoring the needle thread in that the signal transmitter is rotatably arranged in the path of the needle thread and is driven by the latter.

Claims (6)

  1. Sewing machine, having a thread monitor, which comprises the following: a pulse generator, which supplies one pulse per stitch forming cycle, a sensor device having a sensor which responds to the thread consumption, and a counter which is provided with a precharging input and has a resetting input connected to the sensor, characterised in that, in order to use the thread monitor for the monitoring of the gripper thread, the bobbin (6) which is mounted in the gripper body (2) serves as a reflector for the signals emerging from the sensor device (13) and comprises a plurality of reflection areas (10) with different reflecting behaviours, the sensor (14) detecting the signal change caused by the different reflection and feeding such to the resetting input (E1) of the counter (21) as pulses, and in that the precharging input (E2) of the counter (21) is connected to a setting means (25) in order to give different maximum values.
  2. Sewing machine according to claim 1, characterised in that the counter (21), through the intermediary of a connecting element (34), is connected to at least one additional counting means (35, 36), by means of which the switching function of the counter (21) is releasable for a number of stitching cycles for the taking-up of the thread slack after each respective machine function which produces a thread slack.
  3. Sewing machine according to claims 1 and 2, characterised in that the additional counting means (35) is actuatable after an intermediate stop and emits a signal for resetting to the counter (21) after a predeterminable maximum value of main shaft revolutions has been attained.
  4. Sewing machine according to claims 1 to 3, characterised in that the further additional counting means (36) is actuatable after the thread has been cut and emits a signal for resetting to the counter (21) after a predeterminable maximum value of main shaft revolutions has been attained.
  5. Sewing machine according to claims 1 and 2, characterised in that the given value for the additional counting means (35; 36) is adjustable for the taking-up of different sizes of thread slack caused by different machine functions.
  6. Sewing machine according to claim 1, characterised in that the counter (21) is so actuatable, in dependence upon the respective operational state of the sewing machine differing from the sewing operation, that a number of main shaft revolutions, associated with the operational state, is determinable until the changeover to the sewing operation.
EP88907691A 1987-10-21 1988-09-03 Sewing machine with catch thread device Expired - Lifetime EP0387255B1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE3735578 1987-10-21
DE3735578 1987-11-21
DE3800717A DE3800717A1 (en) 1987-10-21 1988-01-13 SEWING MACHINE WITH A THREAD GUARD
DE3800717 1988-01-13

Publications (2)

Publication Number Publication Date
EP0387255A1 EP0387255A1 (en) 1990-09-19
EP0387255B1 true EP0387255B1 (en) 1992-12-09

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Application Number Title Priority Date Filing Date
EP88907691A Expired - Lifetime EP0387255B1 (en) 1987-10-21 1988-09-03 Sewing machine with catch thread device

Country Status (7)

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US (1) US5018465A (en)
EP (1) EP0387255B1 (en)
JP (1) JPH03500612A (en)
KR (1) KR920000853B1 (en)
DE (2) DE3800717A1 (en)
ES (1) ES2010319A6 (en)
WO (1) WO1989003908A1 (en)

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Also Published As

Publication number Publication date
ES2010319A6 (en) 1989-11-01
DE3876634D1 (en) 1993-01-21
US5018465A (en) 1991-05-28
WO1989003908A1 (en) 1989-05-05
KR890701825A (en) 1989-12-21
EP0387255A1 (en) 1990-09-19
DE3800717A1 (en) 1989-05-11
JPH03500612A (en) 1991-02-14
DE3800717C2 (en) 1989-09-14
KR920000853B1 (en) 1992-01-30

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