US2960147A - Heat sealing device - Google Patents

Heat sealing device Download PDF

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Publication number
US2960147A
US2960147A US729050A US72905058A US2960147A US 2960147 A US2960147 A US 2960147A US 729050 A US729050 A US 729050A US 72905058 A US72905058 A US 72905058A US 2960147 A US2960147 A US 2960147A
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United States
Prior art keywords
plastic
air bag
bag
heat sealing
pressurizing
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Expired - Lifetime
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US729050A
Inventor
Ferrell Wesley
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Uniroyal Inc
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United States Rubber Co
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B5/00—Presses characterised by the use of pressing means other than those mentioned in the preceding groups
    • B30B5/02—Presses characterised by the use of pressing means other than those mentioned in the preceding groups wherein the pressing means is in the form of a flexible element, e.g. diaphragm, urged by fluid pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
    • B29C65/22—Heated wire resistive ribbon, resistive band or resistive strip
    • B29C65/221—Heated wire resistive ribbon, resistive band or resistive strip characterised by the type of heated wire, resistive ribbon, band or strip
    • B29C65/224—Heated wire resistive ribbon, resistive band or resistive strip characterised by the type of heated wire, resistive ribbon, band or strip being a resistive ribbon, a resistive band or a resistive strip
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
    • B29C65/22—Heated wire resistive ribbon, resistive band or resistive strip
    • B29C65/228—Heated wire resistive ribbon, resistive band or resistive strip characterised by the means for electrically connecting the ends of said heated wire, resistive ribbon, resistive band or resistive strip
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/48—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding
    • B29C65/50—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding using adhesive tape, e.g. thermoplastic tape; using threads or the like
    • B29C65/5042—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding using adhesive tape, e.g. thermoplastic tape; using threads or the like covering both elements to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/78—Means for handling the parts to be joined, e.g. for making containers or hollow articles, e.g. means for handling sheets, plates, web-like materials, tubular articles, hollow articles or elements to be joined therewith; Means for discharging the joined articles from the joining apparatus
    • B29C65/7841—Holding or clamping means for handling purposes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112—Single lapped joints
    • B29C66/1122—Single lap to lap joints, i.e. overlap joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
    • B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
    • B29C66/43—Joining a relatively small portion of the surface of said articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/814—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/8145—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the constructional aspects of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/81455—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the constructional aspects of the pressing elements, e.g. of the welding jaws or clamps being a fluid inflatable bag or bladder, a diaphragm or a vacuum bag for applying isostatic pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/814—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/8145—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the constructional aspects of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/81461—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the constructional aspects of the pressing elements, e.g. of the welding jaws or clamps being multi-lamellar or segmented, i.e. comprising a plurality of strips, plates or stacked elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/818—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps
    • B29C66/8182—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps characterised by the thermal insulating constructional aspects
    • B29C66/81821—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps characterised by the thermal insulating constructional aspects of the welding jaws
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/818—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps
    • B29C66/8187—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps characterised by the electrical insulating constructional aspects
    • B29C66/81871—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps ; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps characterised by the electrical insulating constructional aspects of the welding jaws
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/82—Pressure application arrangements, e.g. transmission or actuating mechanisms for joining tools or clamps
    • B29C66/824—Actuating mechanisms
    • B29C66/8244—Actuating mechanisms magnetically driven
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/48—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding
    • B29C65/4805—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor using adhesives, i.e. using supplementary joining material; solvent bonding characterised by the type of adhesives
    • B29C65/481—Non-reactive adhesives, e.g. physically hardening adhesives
    • B29C65/4815—Hot melt adhesives, e.g. thermoplastic adhesives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/812—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
    • B29C66/8122—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps characterised by the composition of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/712—Containers; Packaging elements or accessories, Packages
    • B29L2031/7128—Bags, sacks, sachets

Definitions

  • Fig. l is a cross sectional view of a device of the invention.
  • Fig. 2 is a longitudinal line 2-2 of Fig. 1 and,
  • Fig. 3 is a cross sectional 'view of a modification of a portion of the device.
  • the particular embodiment sectional view taken along the tightly together against of the invention shown includes a support assembly 10 v on which are laid plastic sheets 11, 12 to be sealed with a lap joint having an overlying plastic strip 13.
  • a pressurizing assembly 14 is disposed over the joint, in alignment with the support assembly.
  • the support assembly is essentially an electromagnet comprising an iron channel or U-shaped elongated member 15, the web or cross-piece of which is cut back at each end to accommodate an electrical winding 16 made of copper tubing coiled around the web.
  • the conductive winding is insulated with a non-conductor of electricity capable of withstanding high temperatures, such as glass fiber.
  • this coil is energized by passing direct current through it, by means of electrical terminals 17, 18 at each end of the coil.
  • the iron channel is thereby magnetized, the two legs of the channel serving as pole pieces.
  • cooling water is passed through the copper coil to keep the coil temperature down.
  • An electric heater strip 20 imbedded in this surface supplies heat to the area being spliced. Such heater may be energized with alternating current applied at terminals 21, 22 at each end of the strip.
  • the pressurizing assembly 14 comprises a shallow channel 24 closed on both ends to form a box or housing for a flexible heat resistant air bag 25.
  • the housing 24 is open at its lower face and is made of or at least includes iron or similar magnetic material of high permeability, capable of being strongly attracted by the eleetromagnetic support assembly.
  • the air bag may be inflated with air or other fluid, introduced under pressure through a connecting means 26, thus applying pressure to the splice.
  • the connecting means 26 is located toward one end of the air bag, and a similar connecting means 26a is provided toward the opposite end of the air bag, for the purpose of circulating fluid through the bag if desired.
  • a splice may be made on this apparatus as follows:
  • the edges to be spliced are lapped over each other and aligned over the heater strip in the electromagnetic member 10.
  • the pressurizing section 14 containing the air bag is then placed on the sheet so the legs of the upper and lower channels are in alignment.
  • the heatingstrip is relatively narrow compared to the air bag.
  • the power and the support section which is made at least in part of magnetic material, becomes magnetized, the flux lines running up the legs of the support channel through the plastic sheet or gap up into the pressurizing section, forming a closed magnetic circuit with the sheet forming the only gap.
  • the support and pressurizing sections therefore rigidly clamp the plastic.
  • the air bag is then inflated to apply sealing pressure to the splice.
  • the box-like casing confines the air bag, except at the face in contact with the splice.
  • the heater is then turned on to complete the splice.
  • the time. cycle andthe temperature are varied depending on the type of plastic being sealed.
  • a modified form of pressurizing assembly 28 (Fig. 3) may be used.
  • this assembly the box or enclosure for a flexible pressurizing bag 29 is cut lengthwise into narrow strips 30, which are held in position by a plurality of loose fitting pins 31.
  • the magnetic flux is strong enough to hold all the strips the opposing pressure of the air bag.
  • the air bag is deflated and the magnetism turned ed.
  • the box assembly then falls apart into strips which can easily be removed drawn through the same orifice.
  • Example excellent splice was produced usingthe equipment just described as follows:
  • Two sheets of polyvinyl chloride polymer containing 40% plasticizer were lapped over each other of an inch and placed in position over the support member of the sealer equipment.
  • the pressurizing member containing the air bag was then positioned over the splice in alignment with the support or magnetic section.
  • a DC. potential of 12 volts was then applied to the water cooled coil causing a current of amperes to flow through the copper coil.
  • the support and pressurizing sections are thereby magnetically attracted to each other clamping the sheet with a pressure in excess of 500 lbs.
  • the air bag was then inflated to 5 lbs. per square inch to apply this pressure to the lapped splice.
  • Two volts A.C. were then applied to the heater strip causing a current of 200 amperes to flow.
  • the invention affords numerous advantages over prior heat sealing devices.
  • the invention afiords a unique means for applying clamping pressure to both sides of plastic members being heat sealed, without having any mechanical connection between the clamping members.
  • Electromagnetic force is uniquely utilized in the present invention to permit clamping members, not otherwise physically connected, to be urged toward each insuring good contact of the plastic.
  • the ability of the air bag to conform to the exact shape and volume of the plastic insures formation of 'a proper seam.
  • the bag arrangement shown prevents the melted plastic from being squeezed out, which would cause the seam to be thin and therefore weakened. At the same time the air bag insures that proper pressure is applied to the seam.
  • the amount of plastic material at the seam region will vary, and the air bag (not being a solid or rigid member, but being extensible and conformable) is capable of accommodating such variable amounts of material at the seam region.
  • fluid expansible member or bag Another advantage of the fluid expansible member or bag is that it tends to feather out the joint gradually to the sheet thickness, thus resulting in a seam of better appearance.
  • a heat sealing device for joining plastic sheets comprising in combination a supporting assembly "having an elongated generally U-shaped body made of magnetic material, the opposite :arms of which include fiat end surfaces forming a first plane wherein the plastic sheets to be joined may be supported, an electrical winding Wrapped around the cross member of the U-shaped body for operating the U-shaped body as an electromagne't, the said electrical winding comprising an electrically conductive tube through which a cooling fluid can be circulated, a supporting member of insulating material extending across the arms of the U-shaped body for supporting the plastic sheets at the area to be joined, said supporting member having a surface in alignment with the end surfaces of said opposite arms and constituting therewith a planar surface for supporting the plastic what 'I claim and sheets to be joined, a heating element contained in said supporting member for heating the plastic to a molten state at said area, a pressurizing assembly, said pressurizing assembly being disposed in operation above the opposite side of the plastic sheets from said supporting member at the area to be joined,

Description

Nov. 15, 1960 w. FERRELL HEAT SEALING DEVICE Filed April 15, 1958 2 Sheets-Sheet l INVENTOR. WEJZE) Ff/P/Pf y wa AGENT United States Patent HEAT SEALING DEVICE Wesley Ferrell, Fair Lawn, N.J., assignor to United States Rubber Company, v New Jersey Filed Apr. 15, 1958, Ser. No. 729,050 '1 Claim. (Cl. 154-42) New York, N.Y., a corporation of sheets under conditions where both sides of the sheet are f not readily accessible to conventional heat sealing equipment. Such conditions are encountered in the COHSU'UC'. tion of plastic bags or containers. It is also useful in bag construction where the opening or port into the bag is very small.
The invention will be described with reference to the accompanying drawing, wherein:
Fig. l is a cross sectional view of a device of the invention;.
Fig. 2 is a longitudinal line 2-2 of Fig. 1 and,
Fig. 3 is a cross sectional 'view of a modification of a portion of the device.
Referring to the drawings, the particular embodiment sectional view taken along the tightly together against of the invention shown includes a support assembly 10 v on which are laid plastic sheets 11, 12 to be sealed with a lap joint having an overlying plastic strip 13. A pressurizing assembly 14 is disposed over the joint, in alignment with the support assembly.
The support assembly is essentially an electromagnet comprising an iron channel or U-shaped elongated member 15, the web or cross-piece of which is cut back at each end to accommodate an electrical winding 16 made of copper tubing coiled around the web. The conductive winding is insulated with a non-conductor of electricity capable of withstanding high temperatures, such as glass fiber. During operation this coil is energized by passing direct current through it, by means of electrical terminals 17, 18 at each end of the coil. The iron channel is thereby magnetized, the two legs of the channel serving as pole pieces. During operation cooling water is passed through the copper coil to keep the coil temperature down. A piece of rigid heat resistant material 19, such as asbestos-cement board, spans the area between the two legs giving a flush surface between the pole pieces. An electric heater strip 20 imbedded in this surface supplies heat to the area being spliced. Such heater may be energized with alternating current applied at terminals 21, 22 at each end of the strip.
The pressurizing assembly 14 comprises a shallow channel 24 closed on both ends to form a box or housing for a flexible heat resistant air bag 25. The housing 24 is open at its lower face and is made of or at least includes iron or similar magnetic material of high permeability, capable of being strongly attracted by the eleetromagnetic support assembly. The air bag may be inflated with air or other fluid, introduced under pressure through a connecting means 26, thus applying pressure to the splice. The connecting means 26 is located toward one end of the air bag, and a similar connecting means 26a is provided toward the opposite end of the air bag, for the purpose of circulating fluid through the bag if desired.
A splice may be made on this apparatus as follows:
- is then turned on the magnetic coil 16 2,960,147 Patented Nov. 15, 19 60 The edges to be spliced are lapped over each other and aligned over the heater strip in the electromagnetic member 10. The pressurizing section 14 containing the air bag is then placed on the sheet so the legs of the upper and lower channels are in alignment. The heatingstrip is relatively narrow compared to the air bag. The power and the support section, which is made at least in part of magnetic material, becomes magnetized, the flux lines running up the legs of the support channel through the plastic sheet or gap up into the pressurizing section, forming a closed magnetic circuit with the sheet forming the only gap. The support and pressurizing sections therefore rigidly clamp the plastic. The air bag is then inflated to apply sealing pressure to the splice. The box-like casing confines the air bag, except at the face in contact with the splice. The heater is then turned on to complete the splice. The time. cycle andthe temperature are varied depending on the type of plastic being sealed.
For sealing bags or containers having a very small opening, a modified form of pressurizing assembly 28 (Fig. 3) may be used. In this assembly the box or enclosure for a flexible pressurizing bag 29 is cut lengthwise into narrow strips 30, which are held in position by a plurality of loose fitting pins 31. In operation, the magnetic flux is strong enough to hold all the strips the opposing pressure of the air bag, After completion of the splicing the air bag is deflated and the magnetism turned ed. The box assembly then falls apart into strips which can easily be removed drawn through the same orifice.
Example excellent splice was produced usingthe equipment just described as follows:
Two sheets of polyvinyl chloride polymer containing 40% plasticizer were lapped over each other of an inch and placed in position over the support member of the sealer equipment. The pressurizing member containing the air bag was then positioned over the splice in alignment with the support or magnetic section. A DC. potential of 12 volts was then applied to the water cooled coil causing a current of amperes to flow through the copper coil. The support and pressurizing sections are thereby magnetically attracted to each other clamping the sheet with a pressure in excess of 500 lbs. The air bag was then inflated to 5 lbs. per square inch to apply this pressure to the lapped splice. Two volts A.C. were then applied to the heater strip causing a current of 200 amperes to flow. This current was maintained for a period of 12 minutes heating the lapped splice to 390 F; at the end of this time the pressure in the air bag was released and air was allowed to blow through the air bag for two minutes to assist cooling. The magnet was then turned ofi and the sealer removed. Splices formed following the above are essentially molded joints having the strength of the sheet material, and are slightly thicker at the joint, feathering out gradually to the sheet thickness.
From the foregoing, it will be apparent that the invention affords numerous advantages over prior heat sealing devices. The invention afiords a unique means for applying clamping pressure to both sides of plastic members being heat sealed, without having any mechanical connection between the clamping members. Electromagnetic force is uniquely utilized in the present invention to permit clamping members, not otherwise physically connected, to be urged toward each insuring good contact of the plastic The advantages of the air bag scribed will be appreciated when it other forcibly, thus heating strip actually melts the plastic sheets along the seam, and the material coalesces (under pressure) to form the bond. During the time when the plastic is fluid, it is confined by the air bag and cannot allow away froth the seam. The ability of the air bag to conform to the exact shape and volume of the plastic insures formation of 'a proper seam. The bag arrangement shown prevents the melted plastic from being squeezed out, which would cause the seam to be thin and therefore weakened. At the same time the air bag insures that proper pressure is applied to the seam. In practice the amount of plastic material at the seam region will vary, and the air bag (not being a solid or rigid member, but being extensible and conformable) is capable of accommodating such variable amounts of material at the seam region.
Another advantage of the fluid expansible member or bag is that it tends to feather out the joint gradually to the sheet thickness, thus resulting in a seam of better appearance.
Havin thus described my invention, desire to protect by Letters Patent is:
A heat sealing device for joining plastic sheets comprising in combination a supporting assembly "having an elongated generally U-shaped body made of magnetic material, the opposite :arms of which include fiat end surfaces forming a first plane wherein the plastic sheets to be joined may be supported, an electrical winding Wrapped around the cross member of the U-shaped body for operating the U-shaped body as an electromagne't, the said electrical winding comprising an electrically conductive tube through which a cooling fluid can be circulated, a supporting member of insulating material extending across the arms of the U-shaped body for supporting the plastic sheets at the area to be joined, said supporting member having a surface in alignment with the end surfaces of said opposite arms and constituting therewith a planar surface for supporting the plastic what 'I claim and sheets to be joined, a heating element contained in said supporting member for heating the plastic to a molten state at said area, a pressurizing assembly, said pressurizing assembly being disposed in operation above the opposite side of the plastic sheets from said supporting member at the area to be joined, said pressurizing assembly comprising an elongated box-like enclosure made of magnetic material and openat its lower face, said enclosure including sidewall members having fiat end sursaid sidewall members befaces foriifin'g a second plane, ing spaced apart from each other by an amount equal to the spacing between the arms of said U-shaped body whereby when plastic sheets to be joined are positioned between the U-shaped body and the enclosure, and the electrical winding of the 'U shaped body is energized, the arms of the U-shaped body and the sidewalls of the enclosure will be drawn together to clamp the plastic sheets in 'proper'lposition for sealing, a fluid-expansible bag disposed 'within said enclosure, the said bag having an opening for introduein'g an inflating fluid to cause the bag to conform to and confine the plastic at the area to be joined, the said ba'ghaving an additional opening whereby a cooling fluid can be passed through the bag at the conclusion of the splice to cool the said area, the said supporting assembly and pressurizing assembly being held together by the electromagnet during the splicing operation against a separating force'exerted by the fluid-expansible bag.
References Cited in the file of this patent UNITED STATES PATENTS 2,305,010 Kenney et al. Dec. 15, 1942 2,646,195 Langer July 21, 1953 2,713,379 Sisson July 19, 1955 2,725,091 Miner Nov. 29, 1955 2,796,914 Park June 25, 1957 2,822,029 Hoagland -t. Feb. 4, 1958 2,835,776 Blessing May 20, 1958
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Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3111893A (en) * 1960-07-05 1963-11-26 Harry E Hofferberth Laminating and bonding apparatus
US3227597A (en) * 1962-10-02 1966-01-04 Forgrove Mach Wrapping machinery
US3608809A (en) * 1968-08-16 1971-09-28 Western Electric Co Apparatus for uniform multiple-lead bonding
US3661683A (en) * 1970-11-03 1972-05-09 Airline Systems Inc Patch press
DE1627766B1 (en) * 1967-01-09 1972-05-31 Parsons Corp INFLATABLE TOOL FOR APPLYING PRESSURE BONDING SHAPED PARTS
US3863562A (en) * 1972-11-15 1975-02-04 Jax Products Engineering Limit Machine for continuous bonding of fabrics to thermoplastic material
US4104101A (en) * 1972-08-11 1978-08-01 Armen Garabedian Process for making a plastic sheet
US4243368A (en) * 1978-07-31 1981-01-06 Armen Garabedian Apparatus for making a stress-free plastic article
US4628989A (en) * 1982-05-24 1986-12-16 Raychem Corporation Device for heat recovery
EP0282563A1 (en) * 1986-09-09 1988-09-21 BAXTER INTERNATIONAL INC. (a Delaware corporation) Apparatus for heat sealing sheets of thermoplastic material between two electrodes
US5298102A (en) * 1993-01-08 1994-03-29 Sorbilite Inc. Expanding pressure chamber for bonding skins to flat and shaped articles
US5365656A (en) * 1991-09-06 1994-11-22 At&T Corp. Surface mount assembly of devices using AdCon interconnections
EP1083042A2 (en) * 1999-09-10 2001-03-14 Firma Skinetta Pac-Systeme Kiener GmbH & Co. Apparatus for welding and/or welding and cutting of films
US20030221773A1 (en) * 2002-06-04 2003-12-04 Jones Martin T. Apparatus and method for joining polymeric materials using an electro-magnet
US20050221588A1 (en) * 2001-10-19 2005-10-06 Fujitsu Limited Method of manufacturing a semiconductor device and a method for fixing the semiconductor device using substrate jig
US20140263575A1 (en) * 2013-03-14 2014-09-18 Alpha Design Co., Ltd. Element pressing apparatus and heating system using element pressing apparatus
EP2404740B1 (en) * 2008-11-13 2016-10-19 The Boeing Company Method and apparatus for joining composite structural members
US9475230B2 (en) 2008-11-13 2016-10-25 The Boeing Company Heated tool assembly for forming a structural member
US9669579B2 (en) 2008-11-13 2017-06-06 The Boeing Company Aircraft skin attachment system

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2305010A (en) * 1939-12-20 1942-12-15 Walter E Kenney Electric cellophane bag sealer
US2646105A (en) * 1951-04-06 1953-07-21 Langer Nicholas Heat sealing machine
US2713379A (en) * 1952-11-25 1955-07-19 Firestone Tire & Rubber Co Magnetic device for clamping overlapping parts during adhesive bonding
US2725091A (en) * 1949-10-19 1955-11-29 Us Rubber Co Apparatus for joining thermoplastic sheet material
US2796914A (en) * 1950-04-05 1957-06-25 Emhart Mfg Co Heat sealing device
US2822029A (en) * 1955-07-08 1958-02-04 Standard Safety Equipment Co Dielectric heat sealing apparatus
US2835776A (en) * 1954-01-18 1958-05-20 Electronics Process Corp Apparatus for heat sealing plastic films

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2305010A (en) * 1939-12-20 1942-12-15 Walter E Kenney Electric cellophane bag sealer
US2725091A (en) * 1949-10-19 1955-11-29 Us Rubber Co Apparatus for joining thermoplastic sheet material
US2796914A (en) * 1950-04-05 1957-06-25 Emhart Mfg Co Heat sealing device
US2646105A (en) * 1951-04-06 1953-07-21 Langer Nicholas Heat sealing machine
US2713379A (en) * 1952-11-25 1955-07-19 Firestone Tire & Rubber Co Magnetic device for clamping overlapping parts during adhesive bonding
US2835776A (en) * 1954-01-18 1958-05-20 Electronics Process Corp Apparatus for heat sealing plastic films
US2822029A (en) * 1955-07-08 1958-02-04 Standard Safety Equipment Co Dielectric heat sealing apparatus

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3111893A (en) * 1960-07-05 1963-11-26 Harry E Hofferberth Laminating and bonding apparatus
US3227597A (en) * 1962-10-02 1966-01-04 Forgrove Mach Wrapping machinery
DE1627766B1 (en) * 1967-01-09 1972-05-31 Parsons Corp INFLATABLE TOOL FOR APPLYING PRESSURE BONDING SHAPED PARTS
US3608809A (en) * 1968-08-16 1971-09-28 Western Electric Co Apparatus for uniform multiple-lead bonding
US3661683A (en) * 1970-11-03 1972-05-09 Airline Systems Inc Patch press
US4104101A (en) * 1972-08-11 1978-08-01 Armen Garabedian Process for making a plastic sheet
US3863562A (en) * 1972-11-15 1975-02-04 Jax Products Engineering Limit Machine for continuous bonding of fabrics to thermoplastic material
US4243368A (en) * 1978-07-31 1981-01-06 Armen Garabedian Apparatus for making a stress-free plastic article
US4628989A (en) * 1982-05-24 1986-12-16 Raychem Corporation Device for heat recovery
EP0282563A1 (en) * 1986-09-09 1988-09-21 BAXTER INTERNATIONAL INC. (a Delaware corporation) Apparatus for heat sealing sheets of thermoplastic material between two electrodes
EP0282563A4 (en) * 1986-09-09 1989-09-04 Baxter Travenol Lab Apparatus for heat sealing sheets of thermoplastic material between two electrodes.
US5365656A (en) * 1991-09-06 1994-11-22 At&T Corp. Surface mount assembly of devices using AdCon interconnections
US5298102A (en) * 1993-01-08 1994-03-29 Sorbilite Inc. Expanding pressure chamber for bonding skins to flat and shaped articles
EP1083042A2 (en) * 1999-09-10 2001-03-14 Firma Skinetta Pac-Systeme Kiener GmbH & Co. Apparatus for welding and/or welding and cutting of films
EP1083042A3 (en) * 1999-09-10 2002-01-30 Firma Skinetta Pac-Systeme Kiener GmbH & Co. Apparatus for welding and/or welding and cutting of films
US6543202B1 (en) 1999-09-10 2003-04-08 Skinetta Pac-Systeme Kiener Gmbh & Co. Device for welding and/or combined cutting and welding of films
US20050221588A1 (en) * 2001-10-19 2005-10-06 Fujitsu Limited Method of manufacturing a semiconductor device and a method for fixing the semiconductor device using substrate jig
US7395847B2 (en) * 2001-10-19 2008-07-08 Fujitsu Limited Jig for a semiconductor substrate
US20030221773A1 (en) * 2002-06-04 2003-12-04 Jones Martin T. Apparatus and method for joining polymeric materials using an electro-magnet
EP2404740B1 (en) * 2008-11-13 2016-10-19 The Boeing Company Method and apparatus for joining composite structural members
US9475230B2 (en) 2008-11-13 2016-10-25 The Boeing Company Heated tool assembly for forming a structural member
US9669579B2 (en) 2008-11-13 2017-06-06 The Boeing Company Aircraft skin attachment system
US20140263575A1 (en) * 2013-03-14 2014-09-18 Alpha Design Co., Ltd. Element pressing apparatus and heating system using element pressing apparatus
US8875977B2 (en) * 2013-03-14 2014-11-04 Alpha Design Co., Ltd. Element pressing apparatus and heating system using element pressing apparatus

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