Classifications

• • D—TEXTILES; PAPER
  • D05—SEWING; EMBROIDERING; TUFTING
  • D05B—SEWING
  • D05B17/00—Sewing machines for concurrently making thread and welded seams
• • D—TEXTILES; PAPER
  • D05—SEWING; EMBROIDERING; TUFTING
  • D05B—SEWING
  • D05B1/00—General types of sewing apparatus or machines without mechanism for lateral movement of the needle or the work or both
  • D05B1/26—General types of sewing apparatus or machines without mechanism for lateral movement of the needle or the work or both for making fluid-tight seams
• • D—TEXTILES; PAPER
  • D05—SEWING; EMBROIDERING; TUFTING
  • D05B—SEWING
  • D05B19/00—Program-controlled sewing machines
  • D05B19/02—Sewing machines having electronic memory or microprocessor control unit
  • D05B19/12—Sewing machines having electronic memory or microprocessor control unit characterised by control of operation of machine
  • D05B19/16—Control of workpiece movement, e.g. modulation of travel of feed dog
• • D—TEXTILES; PAPER
  • D05—SEWING; EMBROIDERING; TUFTING
  • D05B—SEWING
  • D05B35/00—Work-feeding or -handling elements not otherwise provided for
  • D05B35/06—Work-feeding or -handling elements not otherwise provided for for attaching bands, ribbons, strips, or tapes or for binding
• • D—TEXTILES; PAPER
  • D05—SEWING; EMBROIDERING; TUFTING
  • D05D—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES D05B AND D05C, RELATING TO SEWING, EMBROIDERING AND TUFTING
  • D05D2209/00—Use of special materials
  • D05D2209/10—Particular use of plastics
• • D—TEXTILES; PAPER
  • D05—SEWING; EMBROIDERING; TUFTING
  • D05D—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES D05B AND D05C, RELATING TO SEWING, EMBROIDERING AND TUFTING
  • D05D2305/00—Operations on the work before or after sewing
  • D05D2305/22—Physico-chemical treatments
  • D05D2305/26—Heating

Definitions

• This invention relates to an attachment for an existing sewing machine, including an improved mechanism for pulling fabric members to be sewn to one another using thread comprising a thermoplastic polymer, together with a strip of the same or a different thermoplastic polymer, through a sewing machine while applying heat and pressure thereto, so as to sew the seam and melt the polymer to seal the seam in a single operation.
• the most prevalent method of sealing a sewn seam is to apply a wide tape of thermoplastic polymer with an adhesive layer over a previously sewn seam.
• the garment or other object is supplied to a machine provided with a pair of opposed rollers.
• a polymer substrate on the order of one inch wide with adhesive on one side thereof is heated by a stream of hot air, to activate the adhesive, and is then urged against the seam by the rollers so as to be adhered to the fabric members over the seam as the tape cools, covering the seam.
• seam sealing in fact the seam itself is not literally sealed but is simply covered by the tape.
• This method of seam sealing has many drawbacks, perhaps most notably that it requires the seam to be sealed in a separate operation from the sewing of the seam. Clearly if the seam could be sewn and sealed in a single-operation, substantial economies would be realized in terms of reduced labor requirements, reduced floor space requirements, and reduced equipment costs.
• polymer tape also stiffens the seam in ways that can be uncomfortable and restrict the wearer’s motion in the case of garments and adds additional weight.
• the present application relates to improvements in the mechanism and process described in the Ferreiro application, essentiahy taking it from the “proof-of-concept” status described therein to a fully commercialized device that can be attached readily to various commercial sewing machines.
• One particular improvement relates to the means of application of heat and pressure to seal the seam as it is being sewn.
• One aspect of the present invention is to replace the heated roller opposed to a heated plate or to another heated roller of the Ferriero application with a series of driven heated rollers, typically three, opposed to pairs of heated idler rollers, with a belt disposed over the heated idler rollers, such that the belt urges the fabric members to be joined against the heated driven rollers. This ensures that the fabric members are in contact with the heated driven rollers long enough to ensure effective melting of the polymer, and thereby ensuring that the seam is effectively sealed.
• Another improvement provided according to the present invention is driving the downstream roller slightly faster than the upstream rohers, shghtly stretching the fabric while heating the seam, to ensure that the seam remains well-formed after the polymer cools and hardens.
• Fig. 1 shows a perspective view of the sewing machine, seen from the operator’s side, with the attachment of the invention added thereto, and including a simplified schematic indication of control circuitry provided according to the invention;
• Fig. 2 shows an enlarged perspective view comparable to Fig. 1, illustrating the attachment of the invention in additional detail;
• Fig. 3 shows an enlarged perspective view comparable to Fig. 2, but taken from a point towards the rear of the sewing machine;
• Fig. 4 shows an enlarged elevation of the upper and lower rollers from one side, with the belt passing therebetween;
• Fig. 5 shows an enlarged perspective view comparable to Fig. 2, but of the attachment only, and with one of the rollers in section, showing the cartridge heaters used to heat the rollers;
• Fig. 6 shows a view from the rear of the sewing machine, showing belts used to drive the rollers, and also showing a magnet attached to the flywheel of the sewing machine and a cooperating Hall-effect sensor, used to synchronize operation of the attachment according to the invention to the sewing machine;
• Fig. 7 is a schematic diagram of the electrical circuit provided according to the invention.
• Fig. 8 is a schematic diagram of a compressed air system employed to move the driven rollers into engagement with the fabric members and to preheat the polymer strip.
• a typical commercial sewing machine 10 comprises an upright column 12, in which runs a drive belt from a motor (not shown) disposed under a table 14, the motor being controlled by a foot switch 20 or the like, a transverse arm 16, a sewing mechanism 18, including a needle 19 and a presser foot 21 (see Fig. 2), a lever 13 for lifting the foot 21 out of engagement with fabric members 7 and 9 to be sewn to one another, and a flywheel 22.
• an attachment 24 is attached to the sewing machine 10 by removing a cover plate (not shown) and assembling the
• attachment 24 in place of the cover plate.
• the details of this replacement of the cover plate by the attachment will of course vary somewhat from machine to machine; in each case, the attachment is designed so that the rollers (discussed further below) are disposed directly behind needle 19.
• a reel 23 dispensing a strip 25 of an adhesive thermoplastic polymer, and a feeder assembly 27 for directing the polymer strip 25 into the seam being sewn.
• the strip employed according to the invention may typically be 1/8 - 1 ⁇ 4 inch wide by 0.010- 0.020 inches thick, 0.014 inches being preferred.
• the feeder assembly 27 may be provided with a hot air duct and nozzle, to preheat the polymer strip 25 and activate its adhesive properties prior to its being sewn into the seam.
• Fig. 8 shows details of the air system used to preheat the polymer strip 25.
• an electronic control unit 26 which may comprise a touch screen 28 for receiving user input concerning the parameters necessary to control the process of sealing the seam, such as the temperature of heated rollers that apply heat and pressure to the seam to melt the polymer and seal the seam, and a microprocessor 29 (indicated as a component of computer device 26 as“MP”) for receiving these user inputs and other data, and for providing control signals to the various components of the attachment.
• Fig. 7 shows a block diagram of this circuitry.
• a magnet 30 (see Fig. 6), mechanically affixed to the flywheel 22, and a Hall-effect sensor 32, hkewise mechanically affixed to the upright column 12.
• the sewing machine 10 advances the fabric members 7 and 9 to be sewn together incrementally, by the desired length of the stitch, and the presser foot 21 then holds them in place, so that the needle 19 can puncture the fabric members while stationary.
• flywheel 22 is rotated intermittently.
• the attachment of the invention comprises heated rollers 40, 42, and 44 (see Fig. 4) that are driven to pull the fabric members through the attachment while applying heat and pressure to the seam so as to melt the polymer and seal the seam.
• the driven rollers In order to function properly, the driven rollers must cease pulling on the fabric members during the stitching process.
• HE a signal that is provided to the microprocessor 29 to control two motors 34 and 36 via signals Ml and M2 (Figs. 1 and 7) that drive the rollers.
• Signal HE is thus used to synchronize the operation of the rollers to the remainder of the sewing machine, so as to avoid distorting the fabric.
• the circuitry connecting the microprocessor 29 to the various components providing and receiving the signals noted is not shown in Fig. 1, for clarity of the drawing, but will be readily understood and easily implemented by those of skill in the art. As above, Fig. 7 shows a schematic diagram of this circuitry.
• operation of the sewing machine is controlled by a foot pedal 20 or the like, such as a knee- or hand-operated switch operated by an operator.
• a control signal SW from foot pedal 20 is provided to microprocessor 29 which in turn provides a control signal AC to an air cyhnder 48.
• the assembly of rollers 40, 42, and 44 and of motors 34 and 36 is carried by air cylinder 48 and is withdrawn upwardly, out of engagement with the fabric members, when operation of the sewing machine 10 is stopped by the operator. At the same time the stream of hot air preheating the strip of polymer 25 is shut off.
• the signals provided by microprocessor 29 also include three control signals HI, H2 and H3 provided to rollers 40, 42 and 44 respectively, to control their surface temperature and thereby the amount of heat applied to the seam.
• Control of the surface temperature of these rollers is clearly important to obtaining adequate melting of the polymer of the thread and strip to provide good sealing without scorching or burning the fabric.
• the surface temperature of the rollers can be measured directly using infrared sensors, if such can be found that are sufficiently durable, or the temperature can be controlled indirectly using a feedback loop.
• the rollers can be heated using internal cartridge heaters 51. See Fig. 5. Idler rollers 50 (discussed further below) are likewise heated.
• the cartridge heaters 51 in order that electrical connections can be made to the cartridge heaters 51, they must be stationary, while driven rollers 40, 42 and 46 and idler rollers 50 must rotate freely over heaters 51.
• the heaters 51 are designed to expand when current is applied, typically so as to fit snugly into a hole bored in a volume of material to be heated.
• the cartridge heaters can be disposed in sections 53 of steel tubing, while the rollers may be made of aluminum, bored to be a sliding fit over the steel tubes, and assembled with a small quantity of heat- conducting grease there- between.
• the greater coefficient of thermal expansion of aluminum as compared to that of steel will prevent the heating of the cartridge heaters 51 from interfering with rotation of the rollers.
• thermocouples can be provided to measure the temperatures of the surfaces of the rollers.
• Fig. 4 shows an end view of the assembly of driven heated rollers 40, 42 and 44, heated idler rollers 50, and belt 52 in detail;
• Figs. 2, 3, 5 and 6 show further features provided according to the invention.
• Rollers 50 are carried by a chassis 56 that is assembled to the sewing machine 10, typically by attachment to the hinge (not shown) conventionally provided to allow the sewing machine to be pivoted out of its'’’nest” in the sewing machine table 14.
• Fig. 4 is effectively taken from inside chassis 56, so as to show the ends of rollers 50.
• Chassis 56 has an inclined leading surface 56a (see Fig.
• Chassis 56 is preferably spaced from the sewing machine 10 by insulating spacers (not shown) to allow air to pass there between and avoid overheating the sewing machine 10.
• a continuous belt 52 fits over rollers 50 and moves together with the fabric members 7 and 9 to be sewn, which are indicated by a heavy broken line 58 in Fig. 4.
• Belt 52 rides over a final, unheated roller 60, and is tensioned by springs 54 on either side of the chassis 56, biasing roller 60 (leftwardly in the view of Fig. 4) toward the“downstream” end of chassis 56; the degree of tension in belt 52 may be adjusted by provision of differing springs 54, or by adjustment of the preload provided.
• the biasing roller 60 is mounted in a slot 56b in chassis 56, to allow it to move to adjust the tension in belt 52.
• the fabric members 7 and 9 to be bonded to one another are urged by belt 52 into engagement with rollers 40, 42, and 44 along a lower portion of the circumference of each of rollers 40, 42, and 44 between the opposed pairs of idler rollers 50, ensuring good heat transfer between rollers 40, 42, and 46 on the upper side, to the fabric members indicated at 58.
• belt 52 can be made of a composite of fiberglass cloth coated by one or more layers of Teflon® material.
• the extension of the heat transfer area provided by provision of the belt 52 is highly beneficial in ensuring sufficient heat transfer to effectively melt the polymer materials of the thread 17 and strip 25, and thereby effectively sealing the seam.
• Belt 52 also prevents the fabric members from being tangled in rollers 50.
• the axes of driven rollers 40, 42, and 44 are coplanar, as are those of the idler rollers 50, as illustrated by Fig. 4.
• the spring tension provided to unheated idler roller 60 by springs 54 will cause roller 60 to move leftwardly, so that belt 52 will take a straight-line path over the upper surfaces of idler rollers 50.
• the driven rollers 40, 42, and 44 are brought back downwardly as sewing resumes, the belt 52 will be forced away from the straight-line path so as to conform to the lower circumferential surfaces of rollers 40, 42, and 44 between the respective pairs of idler rollers 50, taking the form shown in Fig. 4, while the springs 54 allow the unheated idler roller 60 to move rightwardly in the view of Fig. 4.
• the practice of the invention will also involve the use of the polymer-laden thread 17 of the Ferriero applications, so that the polymer of the thread 17 is melted at the same time, filling the punctures left by the needle.
• the thread 17 it may be possible to avoid use of the thread 17 in favor of a plain thread, and simply filling the needle punctures with the polymer from the strip 25, and such is accordingly also within the scope of the invention.
• the polymer strip 25 may be avoided and only the thread 17 used.
• the polymers applied to the thread 17 and that of strip 25 may be the same or may differ. As of the filing of this application, experimentation is being performed to identify the optimal materials for these purposes. They may be as disclosed in the Ferreiro application, that is, thermoplastic polyurethane, or possibly materials selected from the group including nylon, polyester, polyolefin and vinyl, and mixtures and combinations thereof. It will be appreciated that these materials have good adhesive properties, so that the seam is strengthened as well as sealed by practice of the invention. The materials used in the prior art seam sealing processes may also be used.
• the polymer is applied to the thread in a bath of molten polymer, so that the polymer is absorbed into the yarns of the thread, followed by passage through a die or the like, squeezing out extra polymer, so the final polymer content of the thread is 2 - 6 % by weight, as in the Ferreiro applications.
• the“upstream” rollers 42 and 44 are driven by motor 36 by way of a first belt 60, while the“downstream” roller 40 is driven separately by motor 34 by way of a second belt 62.
• the motors 34 and 36 are operated responsive to signals Ml and M2 (Figs.l and 7) respectively, so that the rollers can be driven at different speeds as desired.
• the downstream roller 40 is driven at a slightly higher speed than the upstream rollers 42 and 44, so as to exert tension on the assembly of fabric members while the polymer is being melted and the seam compressed, ensuring that the seam is properly formed.
• driven rollers 40, 42, and 44 are knurled as illustrated, so as to ensure adequate friction between these surfaces and the fabric members 7 and 9. A coating is applied to produce a non-stick surface.
• An operator-controlled cutter (not shown) may be provided between the rollers 40, 42, and 44 and presser foot 21, to cut the polymer strip 25 at the end of the seam.
• Rollers 40, 42, and 44 are carried by a frame 64 (Fig. 2) that is pivoted transversely at 66 with respect to the moving actuator 68 of air cylinder 48.
• rollers 40, 42, 44 may also be carried on individual suspensions, spring-biased downwardly with respect to frame 64, for similar reasons.
• Fig. 7 is a schematic diagram of the electrical circuitry provided according to the invention.
• an electronic control unit (ECU) 80 which may comprise microprocessor 29 and associated supporting components, including a user interface such as touch screen 26, receives sensor inputs and provides control signals through appropriate interface circuit boards.
• a set of temperature sensors 70 for the lower roller assembly that is, idler rollers 50
• a set of temperature sensors 72 for the driven rollers 40, 42, and 44 and an air process temperature sensor 73 for measuring the temperature of the stream of air preheating the polymer tape 25
• Sensor input board 74 then performs simple operations on the data, for example, analog-to-digital
• the signals responsive to roller temperature may represent direct measurement of the temperature of the rollers or may represent measurement of the temperature of the cartridge heaters 51.
• the temperature measurement signals are used by ECU 80 to generate temperature control signals by way of a well-known proportional- integral-derivative (PID) feedback loop.
• PID proportional- integral-derivative
• These control signals are then provided to a relay control board 82, which uses the control signals from ECU 80 to drive relays on board 82 to control supply of current to the various heating elements, including the lower assembly heating elements 84, that is, the cartridge heaters in idler rollers 50, the upper assembly heating elements 86, that is, the cartridge heaters in driven rollers 40, 42, and 44, and the air process heating element 88, heating the stream of air employed to preheat the polymer tape 25.
• the lower assembly heating elements 84 that is, the cartridge heaters in idler rollers 50
• the upper assembly heating elements 86 that is, the cartridge heaters in driven rollers 40, 42, and 44
• the air process heating element 88 heating the stream of air employed to preheat the polymer tape 25.
• the signal HE from the Hall-effect sensor 32 is provided to the ECU 80 and used to synchronize the operation of drive motors 34 and 36, by way of provision of signals Ml and M2 to a motor control board 84, which directly controls operation of motors 34 and 36.
• These motors may be of any of a variety of types; stepper motors are currently preferred.
• foot switch 20 provides signal SW to ECU 80, thereby indicating that sewing is to start or to stop.
• ECU 80 provides signal AC to relay control board 82, which then operates the air cylinder via solenoid valve(s) 92 to lift the heated driven rollers 40, 42, and 44 out of engagement with the fabric members to be joined, and likewise operates hot air solenoid 90 to cut off the supply of hot air preheating polymer tape 25. While the fabric members 7 and 9 may remain in contact with belt 52 while rollers 40, 42, and 44 are thus withdrawn, out of engagement with fabric members 7 and 9, the fact that no pressure is then being exerted prevents the fabric from being scorched by heat from the idler rollers 50.
• Fig. 8 shows as mentioned a schematic diagram of the pneumatic components employed.
• Compressed air is supphed at 94 and is supplied to a first solenoid valve 90 which controls flow of air for preheating the polymer strip 25.
• the pressure in the supply line is controlled by a regulator 96, and the air is heated by a heater 88.
• the heater is controlled by control unit 80 in response to a signal from sensor 73, as discussed above.
• the hot air impinges on the polymer strip 25 as it exits feeder 27, as illustrated.
• a second stream of air is provided to solenoid valves 92, connected to air cylinder 48 as shown, in order to controllably raise and lower roller assembly 24 as desired.
• the sewing machine 10 is first preferably supplied with the polymer-bearing thread 17 (Fig. 4) according to the Ferreiro application referred to above.
• the polymer strip 25 is placed between the fabric members 7 and 9, and this assemblage is hand-fed under the presser foot 21.
• the foot switch 20 (or equivalent, such as a knee-operated lever switch) is then actuated by the operator, causing the sewing machine to operate as usual.
• rollers 40, 42, and 44 are brought into engagement with the assemblage of fabric members and polymer strip 25, and are driven in synchronism with the operation of the sewing machine 10 to pull the assemblage between rollers 40, 42, and 44 and idler rollers 50, with belt 52 therebetween, so that the assemblage is heated to melt the polymer of tape 25 and that of the thread 17.
• the preheated polymer strip 25 is drawn into the machine between the two fabric members 7 and 9, the fabric members are stitched together, and a final apphcation of heat to raise the polymer above its solid-to-liquid transition temperature is provided from the rollers.
• the rollers also provide pressure, which flattens the seam, and squeezes the polymer in the seam between the needle punctures.
• the application of pressure also provides better heat transfer through the fabric to the polymer, as well as deforming the lower belt to give greater surface area for improved heat transfer efficiency.
• the polymer After exiting the roller assembly, the polymer rapidly cools and is set. At present, no separate cooling step appears necessary, but such is within the invention if needed.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Sewing Machines And Sewing (AREA)
• Treatment Of Fiber Materials (AREA)
• Lining Or Joining Of Plastics Or The Like (AREA)

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• 2018
  • 2018-02-05 US US15/932,105 patent/US10934647B2/en active Active
• 2019
  • 2019-02-01 ES ES19748424T patent/ES2962759T3/es active Active
  • 2019-02-01 EP EP19748424.9A patent/EP3749508B1/en active Active
  • 2019-02-01 CN CN201980011886.0A patent/CN111819068B/zh active Active
  • 2019-02-01 JP JP2020564029A patent/JP2021512766A/ja not_active Ceased
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• 2022
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