EP0066410A1 - Dispositif coupe-fil sur machine à coudre - Google Patents

Dispositif coupe-fil sur machine à coudre Download PDF

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Publication number
EP0066410A1
EP0066410A1 EP82302537A EP82302537A EP0066410A1 EP 0066410 A1 EP0066410 A1 EP 0066410A1 EP 82302537 A EP82302537 A EP 82302537A EP 82302537 A EP82302537 A EP 82302537A EP 0066410 A1 EP0066410 A1 EP 0066410A1
Authority
EP
European Patent Office
Prior art keywords
thread
looper
catcher
cutting device
cutting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP82302537A
Other languages
German (de)
English (en)
Inventor
Kikuo Mori
Rokuro Yokota
Masashi Teramoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pegasus Co Ltd
Original Assignee
Pegasus Sewing Machine Manufacturing Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP8527081A external-priority patent/JPS57200186A/ja
Priority claimed from JP3358982U external-priority patent/JPS58136086U/ja
Priority claimed from JP3423682U external-priority patent/JPS58136087U/ja
Application filed by Pegasus Sewing Machine Manufacturing Co Ltd filed Critical Pegasus Sewing Machine Manufacturing Co Ltd
Publication of EP0066410A1 publication Critical patent/EP0066410A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05B—SEWING
    • D05B65/00—Devices for severing the needle or lower thread
    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05B—SEWING
    • D05B57/00—Loop takers, e.g. loopers
    • D05B57/02—Loop takers, e.g. loopers for chain-stitch sewing machines, e.g. oscillating

Definitions

  • the present invention relates to a thread cutting device for use in sewing machine. More particularly, it relates to a thread cutting device adapted for use in a double chain stitch sewing machine and a flat seam sewing machine wherein the thread catcher moves reciprocally between the needle plate and the looper to catch the needle thread and the looper thread stretched from the terminal seam to the looper, pull them to the position of the cutting blade, and cut them in cooperation with the cutting blade.
  • the thread cutting devices of the abovementioned type are well known in the double chain stitch sewing machine.
  • a thread tension releasing device designed to release the action of the thread tension adjuster and a thread draw-off device for drawing out a moderate amount of thread from the spool before cutting the thread.
  • Cutting of thread with such a device is conducted in such sequence that, after the stoppage of sewing, i.e., after the needle comes to the top dead center and the looper comes to the most advanced position and the seam forming mechanism stops its movement, the thread tension releasing device and the thread draw-off device are sequentially actuated, followed by the reciprocating motion of the thread catcher.
  • Typical examples of such a type of thread cutting device are disclosed in U.S. Patent Nos. 3,489,115, 3,532,065, and 3,424,117.
  • the present invention is to provide a thread cutting device for sewing machine comprising a thread catcher for catching thread, an operating device for causing reciprocating movement to said thread catcher between the needle plate and the looper, a cutting blade to cut the thread caught by the thread catcher in cooperation with the thread catcher, and a changeover device to cause the thread catcher operating device, which is normally standing still independent from the driving device for the sewing machine, to be subordinate to the driving device of the sewing machine.
  • the changeover device which is operated linked with the operation to close sewing, the thread catcher operating device is rendered to be subordinate to the driving device of the sewing machine so as to/operate the driving device of the sewing machine as the driving source.
  • the thread catcher in the course of the period in which, at the end of the sewing, the needle rises from the bottom dead center to the top dead center, the thread catcher is operated linked with said movement, and after arrival of the needle at the position near the top dead center, cutting of thread takes place.
  • an object of the present invention is to provide a thread cutting device which permits curtailing of the time until the thread cutting is made after the closing operation of sewing and thereby increasing the speed of sewing operation.
  • Another object of the present invention is to.utilize the driving device for the sewing machine as a driving source for the thread catcher operating device and to eliminate the need for any special device for reciprocating the thread catcher such as solenoid or air cylinder.
  • a further object of the present invention is to utilize the driving source for the sewing machine which is the driving source for the thread catcher operating device as a common driving source for the thread tension releasing device and the thread draw-off device to be combined with the thread cutting device and to actuate them prior to the cutting of thread.
  • a still further object of the present invention is to ensure cutting of thread even when the thread catcher is distorted by the tension of the thread applied to said catcher.
  • Fig. 1 shows a double chainstitch sewing machine designed to form double chainstitches by the cooperative actions of the needle 13 and the looper 14.
  • a tension releasing device comprising the known thread tension adjustor 16 and a sliding plate 17 and a thread draw-off device comprising the thread draw-off part 18.
  • the sliding plate 17 and the thread draw-off part 18 are connected in one body so as to move up and down by the rotation of the lever 19.
  • the lever 19 is connected with the thread cutting device generally indicated in numeral 21 arranged in the bed 20 mediated by the link mechanism 22.
  • the sliding plate 17 and the thread draw-off part 18 are moved up linked with the operation of the thread cutting device, by which it invalidates the effect of the thread tension adjuster 16 to release thread tension, and on the other hand pulls up the thread by a certain length to effect thread drawing off from the spool (not shown).
  • the thread cutting device 21 is provided with a cutting blade 25 and a thread catcher 26, as shown in Figs. 2 and 3.
  • the axle 30 is rotatably supported by the guide member 27 mounted to the machine frame (not shown), and stopped with the plate spring 31 by the screw 32 onto the block 28 of the axle 30. Axial shift of the axle 30 is regulated by the block 28 and the pin 29.
  • the slide bar 33, along with the axle 30, is slidably supported to the guide member27, which is mounted to the slide bar 33 by the screw 34, to be moved. forward and backward under the condition pressed to the cutting blade 25 by means of the spring plate 31.
  • the cutting blade and the thread catcher as described above are the same as those of the known devices, excepting that the cutting blade is rotatable.
  • the cutting blade can rotate following after the torsion of the thread catcher, especially when torsion is formed by the tension of the needle thread at the time when the thread catcher catches the thread and pulls it, with the result that the blade edge is always kept in exact contact with the upper surface of the thread catcher without leaving any gap, so that the defective thread cutting attributed to the torsion of the thread catcher is evaded.
  • the thread cutting device further includes a mechanism for actuating the lever 38, on which description will be made hereunder.
  • a guide shaft 43 and a movable shaft 44 in parallel, the guide shaft 43 being fixed to the bracket 42 and the movable shaft 44 in a slidable manner.
  • a block 46 connected with the aforedescribed link mechanism 22, a block 48 protrudingly provided on its lateral side with a pin 47, a guide block 49 with a fork being engaged with the guide shaft 43 for arresting rotation of the movable shaft, and a block 53 having at its top a pin 52 for engagement in a slot 51 formed at the other end of the lever 38.
  • the movable shaft 44 is biased in the right direction in Figs.
  • the guide block 49 may act to arrest rotation of the movable shaft and also to adjust the strength of the spring 55 by adjusting its position of fitting to the movable shaft 44 to either right or left. If there is no need to adjust the spring force, there may be formed on the block 53 a fork riding on the guide shaft 43 so as to provide said block with the function of the guide block 49, i.e., the function to arrest rotation of the movable shaft.
  • a bell crank 58 having at its end a fork portion 57 for slidably fitted over the pin 47 of the block 48 is pivotally supported in rotatable and slidable manner on the shaft 59 protrudingly provided from the bracket 42, and provided with a fork end 60 at the boss portion and a roller 61 at the other end.
  • the bell crank 58 is shifted to the axial direction of the shaft 59 according to the rotation of the lever 63 which is slidably fitted in the fork end 60 of the boss portion to shift the roller 61 to the acting or non-acting position of the arm 66 fixed to the looper drive shaft 65 which causes reciprocating movement to the looper 14 in the direction to intersect at right angles to the direction of advance.
  • the arm 66 is a position separated from the roller 61 when the looper 14 is retracted to the farthest, i.e., when the looper 14 is positioned at the right end on the face of Fig. 1 (ref. Fig. 4), so that the shifting of the shaft 59 of the bell crank 58 is not impeded, and the arm 66 is engaged with the roller 61 on the way of advance of the looper. Accordingly, the bell crank is rotated with the differentiated timing from the looper movement.
  • the above lever 63 fixed to the vertical shaft 68 which is pivotally supported on the bracket 42 causes the above bell crank 58 to be in contact in spring force.with the head portion 59a of the shaft 59 by means of the spring 69, thereby making the roller 61 positioned normally on the non-acting position of the arm 66.
  • a solenoid 71 is provided in order to have the lever 63 rotate against the action of the spring 69 to shift the bell crank 58. It is so designed that, by the excitation of said solenoid, the plunger 73, engagable with the pin 72 which is protrudingly provided on the lever 63, is projected to push the pin 72.
  • the solenoid 71 pushes the bell crank 58 on its excitation and shifts the roller 61 to the acting position of the arm 66.
  • the roller 61 requires to be held at the acting position of said arm against the action of the spring 69 during the time when the looper 14 advances nearly to the most advanced position, i.e., while the arm 66 rotates in clockwise direction..
  • a restraining device comprising a latch lever 76 fitted to the upper end of the vertical shaft 68 and an engaging member 79 having nearly L shaped cross section which is pivotally supported by the shaft 77 fitted to the block (not shown) mounted onto the machine frame and normally having its one end 79a elastically in contact with the upper surface of the latch lever 76.
  • the thread catcher is designed to be operated by the looper drive shaft. However, it may be operated from other moving part of the sewing machine such as a feed shaft which causes to move the feed dog back and forth.
  • the sewing machine furnished with this device is incorporated with a driving motor equipped with a needle positioner of the known type.
  • a driving motor equipped with a needle positioner of the known type.
  • the forward movement of the movable shaft causes a rotary movement to the lever 19 via the link mechanism 22, by which the slidable plate 17 and the thread draw-off part 18 rise to effect release of thread tension and drawing off of thread from the spool as aforementioned.
  • the lever 38 is rotated to slide the slide bar 33, and causes the thread catcher 26 to advance from the condition of Fig. 6A in a manner to follow after the looper 14 (Fig. 6B).
  • the thread catcher also completes its advance (Fig. 6C).
  • the movable shaft 44 is moved back by the action of the spring 55 while causing the bell crank 58 to rotate.
  • this causes the lever 19 to rotate via the link mechanism 22, thereby causing the slidable plate 17 and the thread draw-off part 18 to descend to effectuate the action of the thread tension device 16 and loosen the needle thread and the looper thread, and on the other hand it causes to rotate the lever 38 to retract the thread catcher 26.
  • the thread catcher 26 catches during its retreating movement the needle threads N 1 , N 2 and the looper thread No which are extended from the looper 14 to the terminal end of sewing, draws them to the position of the cutting blade 25, and cuts them in cooperation with the cutting blade (Fig. 6D). Thereafter, the thread catcher is returned to its original position.
  • Figs. 7 to 10 show a device in which the cutting blade is advanced to the cutting position and thread cutting is conducted at a position near the seam forming zone.
  • a shaft 102 is supported in a slidable and rotatable manner, and a slide bar 103 is fitted in a manner to be slidably operated by the lever 105 as in the case of the afore-described slide bar 33.
  • a pin 109 which is to be slidably inserted in the pin hole of the fixing member 108 is protrudingly provided, and on the pin 109 a spring 110 is fitted.
  • the block 107 is biased in a manner to be in contact with the engaging in a manner mounted to the slide bar 103 together with the thread catcher 112. Accordingly, at the time with the thread of the slide bar 103, the cutting blade of the advance of body with the thread catcher 112. At advances in one retreat of the slide bar 103, it recedes with of the thread catcher, pressed by the engaging piece 113 wich is in contact with the block 107. In order to stop the cutting blade 106 which advances with the thread catcher at a certain position, the shaft 102 is protrudingly provided with a stopper pin 115 which is engaged with the guide member 101.
  • the thread cutting is made at the position near the seam forming zone, the length of the idle end of the thread extended from the terminal seam end can be shortened.
  • the cut thread especially the looper thread, should be kept in a held state during the required time for the subsequent start of sewing, otherwise, the cut thread is apt to slip out from the looper under the action of the looper thread cam take-up.
  • a clamp which is in elastic contact with the cutting blade or the thread catcher, so as to clamp the cut thread end in cooperation with the cutting blade or the thread catcher.
  • the looper thread may have a risk of slipping out from the looper.
  • the thread draw-off part 120 having a thread eyelet 118 for leading the looper thread No between the looper thread cam take-up 117 and the looper 14, is formed on the engaging piece 113.
  • a looper thread stopper 121 is inserted the looper thread, which is pulled by the thread draw-off parts 120 which advances in one body with the thread catcher on the forward movement of the thread catcher at the time of the thread cutting.
  • the looper thread stopper 121 is to hold the looper thread until the next first seam is formed after the thread cutting.
  • the looper thread stopper 121 comprises a nearly laid U shaped fitting 124 which is mounted at the lower lateral end portion to the looper thread cam take-up 117 by means of-the screw 123 and a wire spring 126 which extends diagonally upward from one end part mounted to the screw 123, with its other side bent from the middle part, being elastically set in contact with the upper side of the fitting 124 and its foremost end projected from the slit 125 of the fitting 124.
  • the looper thread stopper is disposed at the offset side of the looper thread path between the looper thread cam take-up and the thread guide 128 so as not to be engaged with the looper thread.
  • the cutting blade 106 and the thread catcher 112 advance in one body in a manner to follow after the looper 14, and the thread draw-off part 120 also starts to pull the looper thread N 0 positioned between the looper thread cam take-up 117 and the thread guide 128 in the direction of advance of the thread catcher (Fig. 8).
  • the thread draw-off part 120 After the stoppage of the advance of the cutting blade 106 by the engagement of the stopper pin 115 with the guide member 101, only the thread catcher 112 further advances, and the looper thread pulled by the thread draw-off part is inserted between the wire spring 126 and the upper side of the fitting 124 of the looper thread stopper 121 (Fig. 9).
  • the thread catcher after having reached the most advanced position, retreats on the return movement of the lever 105, and on the way of its retreat catches the needle threads N,, N 2 and the looper thread No which are extended from the looper 14 to the terminal seam, pulls them to the cutting blade 106 positioned at the cutting position, and cuts them.
  • the cut needle threads N1 , N2 and the looper thread No are immediately released without being held, and thereafter the catcher and the cutting blade return to the original positions (Fig. 10). Due to the retreat of the thread draw-off part during this time, the looper thread which had been pulled is loosened, and the looper thread inserted between the upper side part of the fitting and the wire spring is held in the inserted position.
  • the looper thread cam take-up 117 just draws out the looper thread from the spool while absorbing the loosening of the looper thread on the spool side from the looper thread stopper 121 in the initial seam forming period, and it does not reel in the looper thread on the looper side of the looper thread stopper.
  • the looper thread does not slip out from the looper.
  • the thread end comes to be caught by the said seam, and, during the next seam forming period, as the looper threads are simultaneously pulled under tension on both sides of the looper thread stopper by the actions of the looper and the looper thread cam take-up, the looper threads slip out from the looper thread stopper.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Sewing Machines And Sewing (AREA)
EP82302537A 1981-06-02 1982-05-18 Dispositif coupe-fil sur machine à coudre Withdrawn EP0066410A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP85270/81 1981-06-02
JP8527081A JPS57200186A (en) 1981-06-02 1981-06-02 Yarn cutting apparatus of sewing machine
JP33589/82 1982-03-09
JP3358982U JPS58136086U (ja) 1982-03-09 1982-03-09 ミシンの糸切断装置
JP3423682U JPS58136087U (ja) 1982-03-10 1982-03-10 ミシン
JP34236/82 1982-03-10

Publications (1)

Publication Number Publication Date
EP0066410A1 true EP0066410A1 (fr) 1982-12-08

Family

ID=27288131

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82302537A Withdrawn EP0066410A1 (fr) 1981-06-02 1982-05-18 Dispositif coupe-fil sur machine à coudre

Country Status (1)

Country Link
EP (1) EP0066410A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2279970A (en) * 1993-07-14 1995-01-18 Union Special Gmbh A thread cutting device for a chain-stitch sewing machine
CN113388967A (zh) * 2021-07-21 2021-09-14 浙江龙泰缝纫设备有限公司 一种剪线结构以及自动剪线和抬压脚一体的曲折缝纫机

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3359933A (en) * 1964-02-13 1967-12-26 Necchi Spa Thread-cutting mechanism for sewing machines
US3532065A (en) * 1967-09-20 1970-10-06 Rimoldi C Spa Virginio Thread cutting device for sewing machines
US4098209A (en) * 1975-09-02 1978-07-04 Union Special G.M.B.H. Thread cutter for chainstitch sewing machine
US4138958A (en) * 1978-03-02 1979-02-13 The Singer Company Thread trimmer driving mechanism for sewing machines

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3359933A (en) * 1964-02-13 1967-12-26 Necchi Spa Thread-cutting mechanism for sewing machines
US3532065A (en) * 1967-09-20 1970-10-06 Rimoldi C Spa Virginio Thread cutting device for sewing machines
US4098209A (en) * 1975-09-02 1978-07-04 Union Special G.M.B.H. Thread cutter for chainstitch sewing machine
US4138958A (en) * 1978-03-02 1979-02-13 The Singer Company Thread trimmer driving mechanism for sewing machines

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2279970A (en) * 1993-07-14 1995-01-18 Union Special Gmbh A thread cutting device for a chain-stitch sewing machine
GB2279970B (en) * 1993-07-14 1997-04-23 Union Special Gmbh A thread cutting device for a chain-stitch-sewing machine
CN113388967A (zh) * 2021-07-21 2021-09-14 浙江龙泰缝纫设备有限公司 一种剪线结构以及自动剪线和抬压脚一体的曲折缝纫机

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19831114

RIN1 Information on inventor provided before grant (corrected)

Inventor name: MORI, KIKUO

Inventor name: YOKOTA, ROKURO

Inventor name: TERAMOTO, MASASHI