US3541982A - Pneumatic drive system for thread cutting devices for sewing machine - Google Patents

Pneumatic drive system for thread cutting devices for sewing machine Download PDF

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Publication number
US3541982A
US3541982A US784435A US3541982DA US3541982A US 3541982 A US3541982 A US 3541982A US 784435 A US784435 A US 784435A US 3541982D A US3541982D A US 3541982DA US 3541982 A US3541982 A US 3541982A
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United States
Prior art keywords
conduit
rod
piston
needle
sewing machine
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Expired - Lifetime
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US784435A
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English (en)
Inventor
Nerino Marforio
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Virginio Rimoldi and Co SpA
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Virginio Rimoldi and Co SpA
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    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05B—SEWING
    • D05B65/00—Devices for severing the needle or lower thread

Definitions

  • the pneumatic drive device is connected to a pneumatic supply line and to a sensing device for determining whether the sewing needle of the machine is in its uppermost position.
  • the pneumatic drive device is also connected to an auxiliary pneumatic container which, in turn, is connected to a distributing valve.
  • the auxiliary container receives a sufficient amount of compressed fluid to cause the distributing valve to be operated once after each stitching operation of the sewing machine to operate the thread cutting devices.
  • the auxiliary container is supplied with compressed fluid while the sewing machine is running and provides compressed air to the distributing valve when the sewing machine is stopped with its needle located in its uppermost position.
  • the present invention relates to a pneumatic drive system for thread cutting devices of a sewing machine and, more par-' with its own needle selectively positioned in lowermost or uppermost position, said means comprising a driving electric motor and a clutch operating arm for coupling operatively said machine with the motor.
  • the purpose of the present invention is to overcome the above-mentioned inconveniences through the elimination of said faults,
  • the technical problem to be solved is to provide a pneumatic drive system for thread cutting devices having a safety device to prevent the premature thread cutting operation and to prevent therepeating of said operation if it is not intercalated by the execution of some stitches and this to avoid damage either to the machineor to cutters.
  • a pneumatic drive device which is mechanically connected to the clutch operating arm of an electric motor, is connected on one hand to a pneumatic supply line andon the other to acontrol device for controlling the needle positioning and to an auxiliary pneu matic container in its turn connected to a spring rcturnair cylinder by a distributing valve caused to be operated by the control device;
  • the pneumatic drive device being provided to charge the auxiliary container with compressed air when machine is running and to cause the control device to be operated when machine is stopped with its own needle in the uppermost position;
  • the control device being, provided to operate the distributing valve in order to permit the compressed air contained in the auxiliary pneumatic container to be admitted into the spring return air cylinder;
  • the auxiliary pneumatic container being provided to receive a sufficient amount of compressed airfor operating the spring return air cylinder once for each stitching operation because said spring return air cylinder is provided to operate thread cutting devices ofthe machine
  • the main advantage of the present pneumatic drive system lies in the provision of one single thread cutting operation for each stitching operation in order to assure the correct stitching execution restarting of sewing machine.
  • Another advantage reached by the present pneumatic drive system lies in the elimination of any electric element from the drive system for thread cutting device, which is composed entirely by pneumatic elements. From this derives the possibility to provide the sewing machine with electric motor of any type, on condition that said motor is equipped with the needle positioning means; therefore electric circuits of said means do not need these transformations which are otherwise requested by the thread cutting devices for operating them, because the working sequence ofsaid thread cutting devices is entirely different from that of the needle'positioning means.
  • H0. 2 shows an enlarged sectional view of pneumatic drive device
  • FIG. 3 shows the balance wheel of the sewing machine to which the control device for needle positioning can connect; and v FlGS. 4-5 show an enlarged sectional view of said control device.
  • FIG. I is diagrammatically shown a sewing machine 10 having a thread cutting device, not evident in the enclosed drawings, which is equipped with device for cutting and gripping the needle and the looper threads at the end of the stitching operation, after the needle has been automatically positioned in its own uppermost position in correspondence to the top dead center.
  • the sewing machine 10 is caused to be driven by an electric motor 11 equipped with the usual means for performing the selective needle positioning.
  • the electric motor 11 comprises a clutch means of which is evident outwardly a clutch operating arm 12 which is provided to couple the rotor of said motor with a driving pulley 13 in order to cause the sewing machine 10 to be driven by common driving belt 14 and a driven pulley 15.
  • a conventional electriccircuit (not shown) is provided for controlling the operation of electric motor 11.
  • the electric circuit operates in conjunction with clutch operating arm 12.
  • the circuit is designed to stop the needleof the sewing machine in either its uppermostor lowermost position.
  • the connection between the driving pulley l3 and the rotor is determined by moving in a downward direction the clutch operating arm 12 by its own manual control which may be provided in the form of, for example, a common treadle 16.
  • the rod 17 is provided with a pair of nuts 21 adapted for avoiding the slipping of said rod 17 out of the bracket 19 when the treadle 16 is depressed.
  • a return spring 27 provided to maintain the piston 24 in its own rest position in correspondence to which a conduit 28, connected to a pneumatic supply line 29, is connected to a conduit 30 of a normally closed valve 31 of the pneumatic drive device 23.
  • Said valve 31' comprises a cylinder fixed on the upper end of the second rod 20 and within which there is a slideable spring pressed piston 32 equipped with a rod hinged on the clutch operating arm 12 of the motor 11. Between the piston 32 and the upper wall of the cylinder of said valve 31 is mounted a return spring'33 the strength of which is slightly greater than the return spring, not shown, of said clutch operating arm 12. This isprovided for pulling down said lever 12 just before the spring pressed piston 32 moves within the cylinder of normally closed valve 31.
  • the return spring 33 is provided for maintainingsaid piston 32 in its own rest position in correspondence to which the port-of the conduit 30 connecting the three-way handoperated valve 22 to the normally closed valve'31, is closed in such a way that an air passage through the conduit 34 is not possible.
  • conduit 35 which is connected to a needle position sensing device 36.
  • Compressed air is supplied from pneumatic supply line 29 through the threeway hand-operated valve 22 and the conduits 30 and 35 into needle position sensing device 36 wherein the compressed air maintains a piston 41 in its rest position.
  • pneumatic supply line 29 From the pneumatic supply line 29 extends another conduit 37 through which compressed air is supplied to a distributing valve 38 which is directly connected by conduits 39 and 40 to the thread cutting devices of the sewing machine.
  • twinpistons 42 are due to an action of a spring 43 urging a piston 44 of a spring return air cylinder 45 connected to said twinpistons 42 by a rod.
  • the auxiliary container 47 is provided to receive a sufficient amount of compressed air for causing once only the piston 44 of the spring return air cylinder 45 to he slid in contrast tothe action of the spring 43, the auxiliary container being con nected to said cylinder 45 by a conduit 48. a distributing valve 49 of control device 36 and by a conduit 50. At the end ofthe stitching operation. the treadle 16 is released and the same returns to its own rest position in consequence of the combined action of said return spring of the clutch operating arm 12 and of said return spring 33 of the normally closed valve 31.
  • the machine can be restarted or alternatively the thread cutting devices can be operated for cutting as described above.
  • the operation is obtained moving the treadle 16 in areverse direction, namely depressing the back part 51 of the treadle 16 to which correspond mainly both the reversing of the needle position by the operating of a suitable control of the elec tric circuit, not shown, combined with said clutch operating arm 12. and the raising of the fore part 18 and the first rod 17 which slides freely within the bracket 19 which does not move because it is fixed to clutch operating arm 12 through rod and valve 31 which cannot move upwards from the rest positions.
  • the sliding of the first rod 17 moves the adjustable collar 26 against the push rod which is slid jointly to the spring pressed piston 24 in contrast with the action of return spring 27. Said piston. thereby.
  • the push rod 56 is formed with a resilient rod mounted on a pin 57 supported by a plate 58 fixed to a rod 59 of the piston 41.
  • the piston 41 When the piston 41 is pushed to the right by the compressed air flowing from the conduit 52. the push rod 56 reach the balance wheel 53, and engages the slot 54 if the latter is positioned across push rod path. In this case. the piston 41 accomplishes entirely its stroke. 1f needle is not positioned exactly in correspondence to said top dead center.
  • the slot 54 is not disposed across said path in front of the push rod 56 which, thereby, arrives against the balance wheel body, preventing the piston 41 from accomplishing entirely its rightward stroke.
  • the angular extension of the slot 54 has such a valve which allows a needed positioning error of t l millimeter. (0.03937 in.).
  • a pressor foot lifter device has been provided to be inserted ahead of the intake duct of the pneumatic supply line and which is constituted by a three-way manually controlled tapped valve 62 operated by a suitable control constituted, for examplerby a knee-operated control device 63.
  • Said three-way tapped valve which is constantly maintained in a rest position by a suitable spring 64, provides the compressed air passage from intake duct to the pneumatic supply line 29 by twin-pistons 66 appropriately positioned.
  • said pistons 66 are pushed to the right and in such a way the compressed air passage to the pneumatic supply line 29 is interrupted, rendering inactive that portion of the pneumatic control device which is connected to the pneumatic drive device 23.
  • the pneumatic air passage is admitted into a conduit 67 which is connected to a piston 69 suitably connected to the presser foot 70 of the sewing machine 10.
  • the compressed air which is in such a way admitted into the spring return air valve determines the sliding of the piston 69, in opposition to the action of a suitable spring 71, and consequently determines the raising of said presser foot 70.
  • the spring 64 pushes the piston 66 in its own rest position, bringing again said portion ofpneumatic drive device in condition to operate again.
  • a modified embodiment of the pneumatic drive device 23 (see FIG. 2) consists of a normally closed valve 31 for charging with compressed air the auxiliary pneumatic container 47 and of the three-way hand-operated valve 22 for operating the control device for controlling the needle position, both incorporated in a single cylindrical support 72. Within said support are mounted two resilient slidable threaded rods 73 and 74, the end of which project outwards from said cylindrical sup port.
  • the rod 73 of the normally-closed valve 31 is connected to the clutch operating arm 12 of the electric motor 11 and the same is pushed towards the inside of the support 72.
  • Said rod is also provided with a shank 78, which is equipped with a portion 79 having a diameter lightly smaller than said shank and provided for connecting a conduit 80 to a conduit 81 with-which the support 72 is provided.
  • Said rod is formed with a shank 87 inside of the support 72, and said shank is provided with three intermediate portions 88, 89 and 90 having a smaller diameter.
  • the portion 88 is provided'for discharging to atmosphere, through an outlet port 91, the compressed air containedin the conduit 92 connected to the control device 36 likewise to the conduit 35 of FIG. 1.
  • the portion 89 which is provided with a radial hole 93 in connection with an axial hole 94 which is in its turn connecting to the axial hole 82 of the rod 73, is provided to admit the compressed air flowing from the conduit 81, alternatively into the conduit 92 or into a conduit 95 connected to a control device 36 likewise to the conduit 52 of FIG. 1.
  • portion 90 is provided to connect toatmosphere, through an outlet port 96, the conduit 95 when the rod 74 is in its rest position.
  • the clutch operating arm 12 depressed, so that,
  • the rod 74 is urged upwards in contrast to the action otthe spring 84, whilst the support 72 stops, because the annular abutment 77 of the rod 73 prevents'it moving
  • the relative shifting between the support 72 and the rod 74 caused the disposition'of the portion 88 in front of the conduit 92.
  • the compressed air contained in said conduit admitted through the conduit 81 and the holes 83, 82, 94 and 93 and provided for maintaining the control device 36 in its rest position, discharges to atmosphere through the outlet port 91.
  • the portion 89 is disposed in front ofthe conduit 95 which thus is connected to the conduit 81 for admission of the compressed air.
  • a first fluid-operated cylinder for controlling the operation ofthe thread cutting device
  • a fluid-operated needle position sensing device for determining wh'ether the sewing needle is in its uppermost position
  • a treadle normally positioned in an intermediate inoperative position and being selectively movable in a first direction from the intermediate inoperative position to a first operating position and in a second direction from the intermediate inoperative position to a second operating position;
  • a pneumatic drive device connecting the clutch operating arm to said treadle for moving the clutch operating arm to its operative position when said treadle is moved to its first operating position and for returning the clutch operating arm to its inoperative position when said treadleis moved to its second operating position;
  • said pneumatic drive device including a first fluid contro valve connected to said auxiliary fluid container and operated by movement of said treadle to its first operating position for supplying pressurized fluid to said auxiliary fluid container;
  • said pneumatic drive device also including a second fluid control valve connected to said needle position sensing device and operated by movement of said treadle to its second operating position for supplying pressurized fluid to said needle position sensing device to operate said sensing device to determine whether the sewing needle is in its uppermost position; and
  • said pneumatic drive device includes a support. a first rod connecting said support to said first fluid control valve for opening said first fluid control valve when said'treadle is moved to its first operating position and for closing said first fluid control valve when said treadle is moved to its second operating position, and a second rod connected to said treadle and slidably connected to said support for engaging said support when said treadle is moved to its first operating position to move the clutch operating arm to its operative position and for moving relative to said support when said treadle is moved to its second operating position.
  • the needle position sensing device comprises:
  • a second fluid-operated cylinder connected to said second fluid control valve having a piston slidably disposed therein and a push rod projecting from said cylinder and movable with said piston;
  • said means connecting said auxiliary fluid container to said first fluid-operated cylinder includes a distributing valve.
  • said distributing valve having a piston slidably mounted therein and connected to said piston of said second fluid-operated cylinder for closing said distributing valve when said push rod is in a retracted position relative to said wheel and for opening said distributing valve when said push rod is advanced into said slot formed in said wheel.
  • pneumatic drive device comprises:
  • a housing for supporting said first and second fluid control valves therein;
  • a first rod slidably mounted at one end of said housing and connecting said first fluid control valve to the clutch operating arm for operating said first fluid control valve when said treadle is moved to its first operating position;
  • a second rod slidably mounted at the opposite end of said housing and connecting said second fluid control valve to said treadle for operating said second fluid control valve when said treadle is moved to its second operating position.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Sewing Machines And Sewing (AREA)
US784435A 1968-01-16 1968-12-17 Pneumatic drive system for thread cutting devices for sewing machine Expired - Lifetime US3541982A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT1157768 1968-01-16

Publications (1)

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US3541982A true US3541982A (en) 1970-11-24

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US784435A Expired - Lifetime US3541982A (en) 1968-01-16 1968-12-17 Pneumatic drive system for thread cutting devices for sewing machine

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US (1) US3541982A (es)
CH (1) CH492059A (es)
DE (1) DE1901639A1 (es)
ES (1) ES362442A1 (es)
FR (1) FR1602932A (es)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3693562A (en) * 1970-10-23 1972-09-26 Speer Systems Inc Off-the-arm sewing machine and cutting assembly
US3782069A (en) * 1971-11-12 1974-01-01 Fischbein Mfg Dave Bag closing machine with fluidic control system
US3788251A (en) * 1971-12-04 1974-01-29 Union Special Maschinenfab Multistage device for the control of the air supply for pneumatic aligning members
FR2385833A1 (fr) * 1977-03-28 1978-10-27 Cluett Peabody & Co Inc Dispositif de distribution et d'orientation de boutons, pour machines a coudre
US4271775A (en) * 1979-08-17 1981-06-09 Tice Engineering & Sales, Inc. Needle positioner for high speed stitching machines
US4546716A (en) * 1984-07-30 1985-10-15 Porter Sewing Machines, Inc. Double overlock seamer
US4690081A (en) * 1983-08-12 1987-09-01 Awfi Arbeitswissenschaffliches Forschungsinstitut Gmbh Sewing machine
US20140373765A1 (en) * 2013-06-25 2014-12-25 Zeng Hsing Industrial Co., Ltd. Knee-controlled motor control device for a motor-driven presser mechanism of a sewing machine

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110359194B (zh) * 2019-07-24 2021-06-04 杰克缝纫机股份有限公司 一种剪线吸风装置及缝纫机

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3693562A (en) * 1970-10-23 1972-09-26 Speer Systems Inc Off-the-arm sewing machine and cutting assembly
US3782069A (en) * 1971-11-12 1974-01-01 Fischbein Mfg Dave Bag closing machine with fluidic control system
US3788251A (en) * 1971-12-04 1974-01-29 Union Special Maschinenfab Multistage device for the control of the air supply for pneumatic aligning members
FR2385833A1 (fr) * 1977-03-28 1978-10-27 Cluett Peabody & Co Inc Dispositif de distribution et d'orientation de boutons, pour machines a coudre
US4154177A (en) * 1977-03-28 1979-05-15 Cluett, Peabody & Co., Inc. Button feeding and orienting system for sewing machines
US4271775A (en) * 1979-08-17 1981-06-09 Tice Engineering & Sales, Inc. Needle positioner for high speed stitching machines
US4690081A (en) * 1983-08-12 1987-09-01 Awfi Arbeitswissenschaffliches Forschungsinstitut Gmbh Sewing machine
US4546716A (en) * 1984-07-30 1985-10-15 Porter Sewing Machines, Inc. Double overlock seamer
US20140373765A1 (en) * 2013-06-25 2014-12-25 Zeng Hsing Industrial Co., Ltd. Knee-controlled motor control device for a motor-driven presser mechanism of a sewing machine

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Publication number Publication date
ES362442A1 (es) 1970-12-01
DE1901639A1 (de) 1970-02-05
FR1602932A (es) 1971-02-22
CH492059A (it) 1970-06-15

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