US3587497A - Thread breakage detector - Google Patents

Thread breakage detector Download PDF

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Publication number
US3587497A
US3587497A US795291*A US3587497DA US3587497A US 3587497 A US3587497 A US 3587497A US 3587497D A US3587497D A US 3587497DA US 3587497 A US3587497 A US 3587497A
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United States
Prior art keywords
thread
sewing machine
contact
relay
thread breakage
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Expired - Lifetime
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US795291*A
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English (en)
Inventor
Aubrey G Beazley
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Farah Manufacturing Co Inc
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Farah Manufacturing Co Inc
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Publication date
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    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05B—SEWING
    • D05B51/00—Applications of needle-thread guards; Thread-break detectors

Definitions

  • This invention relates to sewing machines and means for controlling the same, more particularly, this invention relates to an improved device for signalling the necessity for stopping a sewing machine upon failure in performance of the upper or needle thread.
  • devices which determine, by being acted upon by the thread itself, the thread tension or absence thereofduringone or more of the eventsmaking up a repeating stitching cycle.
  • Appropriate electrical means programmed to sense thefailure of the mechanical thread detecting means then signal the desired information, i.e., either stopping the sewing machine or notifyingan observer of the failure by the machine to perform-in the conventional manner.
  • a representative device of this type is illustrated in US. Pat. No. 3,029,763.
  • the present invention relates to means detecting upper thread failure classified with the second group of devices.
  • FIG. 1 shows a conventional threadtensioning device positioned on a sewing machine head and which device is representative of those used on high speedsewing machines;
  • FIG. 2 illustrates a top'view of the thread tensioning device
  • FIG. 3 illustrates a side view of the threadtensioning device; and wherein FIG. 4 illustrates the novel electrical circuit used to detach reliably the thread failure during a high speed sewing operation.
  • a thread tensioning device 2 consists of a pair of tension discs 3 and 4 pressed together by a spring 5 on an axis 6 and adaptedto grip a thread 7.
  • a thread takeup spring 8 pivots about the axis 6 of the thread tensioner 2. This thread takeup spring 8 is loaded to exert force in clockwise direction until it comes to rest under spring tension against 'a contact block 9. The thread is routed down and up, halfway around the thread tensioner. axis 6 and in the up position through a loop in the thread takeup spring, then back down and around a tension thread guard 11, and thenup through a takeup arm 12 having an eye therefor.
  • the thread takeup spring 8 makes and breaks contact with the contact block once for each stitching or thread feed" cycle. If the needle thread 7 is under tension for a period of each cycle, then it is an exact indication that the needle thread is sewing properly. However, if the needle thread 7 breaks, then the needle thread is no longer undertension, and the thread takeup spring 8 rests continuously against the contact block 9 even though the sewing machinev is running.
  • the thread takeup spring 8 and the contact block 9 are used as electrical contacts, lint will rapidly build up on the contact surfaces of the same. Within short time of the operation, the contacts are rendered ineffective for operating a relay circuit. Moreover, these contacts must use a low voltage source for safety, and contact resistance of very low values must be used for energizing relays. Further, contact resistance of varying value builds up due to varying levels of lint contamination associated with materials having different resistivity characteristics.
  • the thread tensioner axis 6 in some high speed sewing machines is an axially reciprocating cam follower periodically spreading apart one of the two thread tensioner discs 3 and 4. Consequently, axis 6 carries on its surface some machine oil which has a tendency to attract lint.
  • an electronic detection and event programming means are now employed with suitable signalling means either to call to an operator's attention the failure in the thread tension or to stop by appropriate means the sewing machine operation.
  • the detection means electronically transforms the inlet contaminated high resistance contacts to a low impedance relay drive.
  • the electronic circuit'used for detecting the failure in the upper thread is depicted in FIG. 4.
  • the indicated solid state device i.e., transistor 13 is off, as is the indicated solid state device, i.e., transistor 14.
  • the relay 15 is then deenergized.
  • the relay 16 is connected to energize under conditions when the sewing machine motor clutch (not shown) is actuated. Hence, the signal light 17 can turn on only under certain conditions when the clutch is actuated and not when the clutch is not actuated (or means are provided to deactivate the clutch and retain the signal light under appropriately needed conditions). Thus, relay 16, when energized, establishes the condition that the sewing machine must be running in order for the signal light 17 to be turned on.
  • the relay 15 is energized when the thread takeup spring is rapidly making and breaking contact (on-off condition) with the contact block 9 causing the capacitor 18 to charge rapidly and discharge slowly.
  • capacitor 18 produces a net positive voltage at the solid state device, i.e., at transistor 13 emitter, providing base drive to turn on the solid state device, i.e., transistor 14 and to energize relay 15, thereby keeping the signal light 17 in the off position. If the needle thread 7 were to break while the machine is running, the capacitor 18 will no longer have a charging path because the thread takeup spring 8 will be making continuous contact with the contact block 9 causing thereby transistor 13 to lose base drive.
  • Circuit parameters may be adjusted so that when the contact resistance buildup on the thread takeup spring8 because of line or other contaminants reaches the proportions of several thousand ohms this resistance will not affect the circuit operation.
  • An upper thread tension detection and sewing machine control arrangement particularly for determining the failure ofa sewing machine to perform satisfactorily when the upper thread fails to perform in the set manner during a stitching cycle, comprising:
  • switch means including a high impedance source of current, operative in a repeating open and closed condition synchronous to a sewing machine stitching cycle for providing an open and closed signal; said switch means being of a varying resistance when closed as a result of contaminants in an operative environment for the sewing machine; and variation of said closed signal due to said varying resistance being negligible due to said high impedance sourcej detection means, connected to the varying resistance switch means for generating a control signal in response to the said detection means generates a signal responsiveto the switch means when said switch means is In a continuous on condition.
  • tion means include a capacitor and two transistors, said capacitor is charged when said switch is in the repeating openclosed condition and said capacitor provides a net voltage for the first transistor to provide a base drive to the second transistor energizing said relay.
  • the detection means include a capacitor and a transistor, said capacitor providing a net positive voltage when said switch is in the repeating open and closed condition in an emitter of the transistor to energize said relay connected to said signal means.
  • the upper thread tension detection and sewing machine control arrangement wherein the switch means is a thread takeup spring and a contact block and wherein the detection means operates an emitter follower which transforms the high resistance contacts of said takeup spring and contact block into a low impedance for the relay means, and wherein the relay means when said sewing machine is running is in an energized condition and keeps the signal means deactivated when the switch means is in a repeating open and closed condition.
  • An upper thread tension detection switch arrangement for a sewing machine having a thread takeup spring and a contact block which are separated and brought together by the sewing machine's upper thread during normal sewing operation comprising switching means including said spring and block as contacts, one of said contacts being connected to a reference potential, a high impedance connected to the other of said contacts and to a source of potential, said contacts being of varying resistance as a result of contaminants in an operative environment of the sewing machine, and the resistance of said high impedance being several times larger than the largest varying resistance of said contacts when closed for rendering negligible variations in current through said closed contacts as a result of the contact impedance variation.
  • An upper thread tension detection arrangement for a sewing machine having a thread takeup spring and a contact block which are separated and brought together by the sewing machine's upper thread during normal sewing operation comprising a pair of time constant circuits including a capacitor, said circuits respectively charging and discharging said capacitor said circuits including means providing for different rates of charging and discharging of such capacitor; a switching means including said spring and block as contacts for operating said time constant circuits to alternately charge and discharge said circuits and including high impedance means having a large resistance connected with said contacts for rendering said switching substantially immune from resistance variations across said contacts resulting from an accumulation of contaminants thereon.
US795291*A 1969-01-30 1969-01-30 Thread breakage detector Expired - Lifetime US3587497A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US79529169A 1969-01-30 1969-01-30

Publications (1)

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US3587497A true US3587497A (en) 1971-06-28

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Application Number Title Priority Date Filing Date
US795291*A Expired - Lifetime US3587497A (en) 1969-01-30 1969-01-30 Thread breakage detector

Country Status (9)

Country Link
US (1) US3587497A (ja)
JP (1) JPS5231784B1 (ja)
AT (1) AT302791B (ja)
BE (1) BE741366A (ja)
CH (1) CH494851A (ja)
CS (1) CS151539B2 (ja)
DE (1) DE1957749A1 (ja)
GB (1) GB1289990A (ja)
SE (1) SE357586B (ja)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3756524A (en) * 1970-03-24 1973-09-04 Zellweger Uster Ag Electronic monitoring apparatus and monitoring method for textile materials
US4102283A (en) * 1976-11-01 1978-07-25 Cluett, Peabody & Co., Inc. Skipped stitch detector for chain stitch sewing machines
US4170951A (en) * 1978-12-14 1979-10-16 The Singer Company Skipped stitch detection system
US4710646A (en) * 1985-04-03 1987-12-01 Elitex Koncern Textilniho Strojirenstvi Thread movement sensor
US4735161A (en) * 1986-10-20 1988-04-05 Sew Simple Systems, Inc. Sewing machine thread breakage detector
US5383417A (en) * 1992-10-26 1995-01-24 Norrid; Paul E. Needle thread stitch formation monitor
US7204137B1 (en) * 2003-08-20 2007-04-17 Essex, Inc. Thread breakage detection systems and methods
CN103184665A (zh) * 2013-03-29 2013-07-03 黄站 绣花机报警装置
CN105734863A (zh) * 2016-04-29 2016-07-06 句容市行香光明绣花厂 一种更稳定的改进绣花机提示工装
CN105908401A (zh) * 2016-06-24 2016-08-31 杰克缝纫机股份有限公司 压力感应式断线检测机构及缝纫机
USD846006S1 (en) * 2017-03-22 2019-04-16 Tokai Kogyo Mishin Kabushiki Kaisha Combined thread tension device and thread breakage detector mounted on thread tension table for embroidery sewing machine
USD846005S1 (en) 2017-03-22 2019-04-16 Tokai Kogyo Mishin Kabushiki Kaisha Spool holder for an embroidery sewing machine
USD846007S1 (en) 2017-03-22 2019-04-16 Tokai Kogyo Mishin Kabushiki Kaisha Thread guide for embroidery sewing machine

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2135703A (en) * 1983-02-25 1984-09-05 Celestion Wood Limited Warning device
CN105937101A (zh) * 2016-06-24 2016-09-14 杰克缝纫机股份有限公司 一种缝纫机及其断线检测机构

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3756524A (en) * 1970-03-24 1973-09-04 Zellweger Uster Ag Electronic monitoring apparatus and monitoring method for textile materials
US4102283A (en) * 1976-11-01 1978-07-25 Cluett, Peabody & Co., Inc. Skipped stitch detector for chain stitch sewing machines
US4170951A (en) * 1978-12-14 1979-10-16 The Singer Company Skipped stitch detection system
US4710646A (en) * 1985-04-03 1987-12-01 Elitex Koncern Textilniho Strojirenstvi Thread movement sensor
US4735161A (en) * 1986-10-20 1988-04-05 Sew Simple Systems, Inc. Sewing machine thread breakage detector
US5383417A (en) * 1992-10-26 1995-01-24 Norrid; Paul E. Needle thread stitch formation monitor
US7204137B1 (en) * 2003-08-20 2007-04-17 Essex, Inc. Thread breakage detection systems and methods
CN103184665A (zh) * 2013-03-29 2013-07-03 黄站 绣花机报警装置
CN105734863A (zh) * 2016-04-29 2016-07-06 句容市行香光明绣花厂 一种更稳定的改进绣花机提示工装
CN105908401A (zh) * 2016-06-24 2016-08-31 杰克缝纫机股份有限公司 压力感应式断线检测机构及缝纫机
USD846006S1 (en) * 2017-03-22 2019-04-16 Tokai Kogyo Mishin Kabushiki Kaisha Combined thread tension device and thread breakage detector mounted on thread tension table for embroidery sewing machine
USD846005S1 (en) 2017-03-22 2019-04-16 Tokai Kogyo Mishin Kabushiki Kaisha Spool holder for an embroidery sewing machine
USD846007S1 (en) 2017-03-22 2019-04-16 Tokai Kogyo Mishin Kabushiki Kaisha Thread guide for embroidery sewing machine

Also Published As

Publication number Publication date
CH494851A (de) 1970-08-15
AT302791B (de) 1972-10-25
JPS5231784B1 (ja) 1977-08-17
DE1957749A1 (de) 1971-06-16
CS151539B2 (ja) 1973-10-19
GB1289990A (ja) 1972-09-20
BE741366A (ja) 1970-04-16
SE357586B (ja) 1973-07-02

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