Classifications

• • 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
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
  • B29C45/14336—Coating a portion of the article, e.g. the edge of the article
  • B29C45/14418—Sealing means between mould and article
• • 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
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/0038—Moulds or cores; Details thereof or accessories therefor with sealing means or the like
  • B29C33/0044—Moulds or cores; Details thereof or accessories therefor with sealing means or the like for sealing off parts of inserts projecting into the mould cavity
• • 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
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/68—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts by incorporating or moulding on preformed parts, e.g. inserts or layers, e.g. foam blocks
  • B29C70/74—Moulding material on a relatively small portion of the preformed part, e.g. outsert moulding
• • 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
  • B29L2031/26—Sealing devices, e.g. packaging for pistons or pipe joints
  • B29L2031/265—Packings, Gaskets
• • 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
  • B29L2031/30—Vehicles, e.g. ships or aircraft, or body parts thereof
  • B29L2031/3055—Cars
• • 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
  • B29L2031/778—Windows
  • B29L2031/7782—Glazing

Definitions

• the present invention relates to a seal assembly for use in an injection molding process and, more particularly, to a seal assembly for use in a mold for making encapsulated window structures.
• fixed window assemblies for vehicles were comprised of a plurality of elements including adhesive sealants applied around the marginal edges of a glass sheet, suitable mechanical fasteners such as metal clips, and exterior decorative trim strips disposed to cover the junction between the marginal edges of the glass sheet and the adjacent portions of the vehicle frame.
• Such window structures were costly, especially from a labor standpoint, since it was necessary to assemble the individual elements along the vehicle assembly line.
• unitary window assemblies of the type illustrated in U.S. Patent No. 4,072,340 were developed. These window assemblies included a sheet of glass, an adjacent frame, and a casing or gasket of molded material, such as polyvinylchloride, extending between the frame and the peripheral edge of the window to hold the sheet of glass and the frame together. Fasteners were provided at spaced locations along the frame such that the entire assembly could be guided into a location over the opening in a vehicle body as a unit. Other types of unitary window assemblies are disclosed in U.S. Patents Nos. 3,759,004 and 4,365,595.
• window assemblies have been formed by encapsulating at least a portion of the periphery of a sheet of glass with a gasket material.
• the gasket is formed by curing a polymeric gasket-forming material in situ on the glass sheet to encapsulate a predetermined portion of the marginal edge of the sheet.
• the gasket can be polyure hane and formed, for example, by a reaction injection mglding process.
• a mold structure which can be utilized to encapsulate a glass sheet with an integrally molded gasket is disclosed in U.S. Patent No. 4,561,625 issued to W. R. Weaver and assigned to the assignee of the present invention.
• the mold structure includes at least two mold sections having facing surfaces cooperating to define a chamber for receiving a glass sheet.
• a resilient seal means is positioned in at least one of the mold sections about at least a portion of the periphery of the chamber and functions to resiliently support the glass sheet within the chamber.
• Each mold section includes a metallic main body portion, and the seal means maintains at least the portion of the glass sheet located inwardly of the seal means in spaced-apart relationship with the metallic main body portions of the mold sections.
• the seal means cooperates with predetermined portions of the glass sheet and the mold sections for defining a gasket forming cavity having a configuration corresponding to the gasket to be formed on the glass sheet. At least a portion of the facing surfaces of the mold sections disposed outwardly of the gasket forming cavity are in metal-to-metal contact with one another. This enables the amount the seal means is compressed and the dimensions of the gasket to be controlled.
• the prior art seals are typically deformable, static silicone rubber or teflon coated elastomeric seals.
• the present invention relates to a unique seal assembly for a mold structure for molding a gasket in situ around the periphery of a glass window assembly.
• the seal assembly is adapted to resiliently support the window assembly within the mold structure and cooperates with the mold structure for defining a gasket forming cavity.
• the seal structure of the present invention is dynamic and includes a fluid filled bladder which automatically compensates for pressure differentials caused by low and high spots in the sheet of glass. With the present invention, excessive pressure generated at a high spot on the glass is transferred to an adjacent low spot to equalize the pressure along the whole length of the seal.
• the mold structure typically includes two cooperating mold sections, each of which can be provided with a groove for receiving separate dynamic seal assemblies.
• Each seal assembly includes a sealing body constructed of a deformable, non-compressible material and having a sealing surface which faces and is adapted to sealingly contact the window assembly and preferably at least one outwardly extending fin formed thereon in contact with a wall of the groove.
• the seal assembly also includes a fluid filled bladder positioned between the sealing body and the cooperating mold section. When increased pressure is applied to a local area of the seal as a result of a contour difference between the seal and the window assembly, the bladder deforms to automatically transfer at least a portion of the applied pressure to adjacent areas of the seal.
• Such a seal construction produces a more effective seal and reduces seal fatigue, thereby increasing the life of the seal, and assures molding an undistorted, true to design, molded gasket.
• FIG. 1 is a fragmentary. sectional view of a prior art window assembly and mold structure
• Fig. 2 is a fragmentary elevational view of the prior art window assembly and seal of Fig. 1;
• Fig. 3 is a fragmentary sectional view of a window assembly and mold structure incorporating a seal assembly in accordance with the present invention
• Fig. 4 is a fragmentary elevational view of the window structure and seal assembly shown in Fig. 3;
• Fig. 5 is a partial schematic, partial fragmentary elevational view of a seal assembly and bladder operating system according to the present invention
• Fig. 6 is a fragmentary sectional view of a preferred embodiment of the seal assembly according to the present invention
• Fig. 7 is a fragmentary sectional view of another embodiment of the seal assembly according to the present invention.
• FIG. 1 a window assembly 10 positioned within a mold structure 11 utilizing a seal according to a prior art mold structure of the type disclosed in above-mentioned U.S. Patent No. 4,561,625, which is herein incorporated by reference.
• the mold structure 11 includes a lower section 12 and an upper section 13 which are coupled to suitable means (not shown) for opening and closing the mold sections 12 and 13.
• the mold structures 12 and 13 are typically formed of a rigid material such as, for example, steel or aluminum.
• each of the mold sections 12 and 13 can be provided with passageways (not shown) for circulating a suitable coolant or heating fluid through the respective mold sections.
• the mold sections 12 and 13 are provided with recessed portions 14 and 15 respectively in facing relationship to one another such that, when the mold sections are closed, the recessed portions 14 and 15 cooperate to define a sheet receiving or glass clearance chamber for receiving the window assembly 10 on which a gasket is to be formed.
• the window assembly 10 is positioned on the lower section 12 so that the outer peripheral portion of the lower surface of the glass rests on a resilient lower seal 16 positioned within a groove 17 formed in the upper surface of the lower section 12.
• the upper mold section 13 is lowered into position to enable the outer peripheral portions of the facing surfaces 18 and 19 of the cooperating mold sections 12 and 13 respectively to be clamped in metal-to-metal contact, as shown in Fig. 1.
• the upper mold section 13 carries a resilient upper seal 20 positioned in a groove 21 formed opposite the groove 17.
• the upper seal 20 cooperates with the lower seal 16 to press yieldingly against the glass sheet window assembly 10 and resiliently support the window assembly within the glass clearance chamber.
• the chamber or space between the surfaces of the recessed portions 14 and 15 is slightly larger than the thickness of the window assembly 10.
• the glass clearance chamber can be formed of any shape as long as the chamber is sufficiently large to avoid any glass-to-metal contact between the glass sheets of the window assembly 10 and the metallic mold sections 12 and 13.
• the portions of the mold sections 12 and 13 which are below and above respectively the central portion of the glass sheet window assembly 10 can be removed such that each mold section will be generally ring-shaped.
• the seals 16 and 20 are preferably formed of a silicone rubber material and secured within the respective grooves 17 and 21 by means of a suitable adhesive.
• the seals 16 and 20 cooperate with selected portions of the window assembly 10 and the mold sections 12 and 13 for defining a gasket forming cavity utilized to form a gasket 22 about the peripheral edge of the window assembly 10. More specifically, in Fig. 1, the gasket forming cavity is defined by the cooperation of a lower gasket shaping surface 23 of the lower mold section 12, an upper gasket shaping surface 24 of the upper mold section 13, portions 16a and 20a of the seals 16 and 20 respectively, and the peripheral edge portion of the window assembly 10.
• the gasket forming cavity can be constructed to form the gasket 22 on either the entire periphery of the window assembly 10, or on a selected peripheral portion.
• a flowable polymeric gasket forming material can be injected into the cavity through suitable inlet means (not shown) .
• Fig. 2 there is shown an elevational view of a portion of the window assembly 10 and the lower seal 16. While the seal 16 is ideally constructed with a contour which conforms to the contour of the edge of the window assembly 10, due to the normal glass forming and bending operations, the window assembly often has a contour which is slightly different from the contour of the seal 16. In Fig. 2, there is shown at 25 a difference in contour between a peripheral edge portion of the window assembly 10 and an upwardly facing portion of the seal 16.
• the lower surface of the window assembly 10 in the area 25 is spaced upwardly from the seal 16 when the window assembly is placed on the upper surface of the seal 16.
• the contour difference 25 forms a space or gap 26 which, prior to the injection of the gasket forming material, must be sealed in order to prevent leakage of the gasket forming material past the seal 16, thereby producing undesirable flash on the finished gasket.
• a window assembly 30, similar to the window assembly 10, is positioned in a mold 31 having a lower section 32 and an upper section 33.
• the mold sections 32 and 33 are typically formed of a metallic material and have recessed portions 34 and 35 respectively to form a chamber for receiving the window assembly 30 and preventing glass-to-metal contact between the window assembly and the mold sections.
• a lower seal body 36 constructed of a deformable, non-compressible material such as silicone is positioned in a groove 37 and has a sealing surface 36a which engages a lower surface of the window assembly 30 to support the window assembly above the lower section 32.
• the groove 37 has an upwardly facing rounded bottom wall 38 which conforms to an outside surface of a tubular bladder 39.
• the lower surface of the seal 36 has a downwardly facing groove 40 formed therein for accepting the tubular bladder 39.
• An upper seal body 41 constructed of material similar to the lower seal body 36 is located in a groove 42 formed in the upper section 33 and has a sealing surface 41a which engages the window assembly 30.
• the upper surface of the upper seal 41 and the upper wall of the groove 42 are grooved and shaped to retain a tubular bladder 43.
• the lower section 32 and the upper section 33 have a lower cavity 44 and an upper cavity 45 respectively formed therein for forming a gasket 46 which is similar to the gasket 24.
• FIG. 4 there is shown a fragmentary elevational view of the window assembly 30, the lower seal 36 and lower tubular bladder 39.
• a contour difference 47 in the window assembly 30 is similar to the contour difference 25 of the window assembly 10 shown in Fig. 2.
• the dynamic seal according to the present invention automatically compensates for pressure differentials caused by contour differences and transfers compressive forces from "low spots” to "high spots". Therefore / the seal 36 is stressed evenly and tends to last longer and seal more reliably than the prior art seals shown in Fig. 1 and Fig. 2 and assures fill-out and undistorted gasket shape.
• the upper and lower seals extend around those portions of the window periphery to which the gasket is to be molded.
• the associated bladder can be filled with a predetermined amount of fluid and subsequently sealed. If the gasket is to be formed around the entire periphery, the upper and lower seals in the mold will be formed as rings. The bladder under the seals will also be formed as a ring.
• the interior of the bladder can be connected to a source of pressurized fluid in a manner as illustrated in Fig. 5.
• the bladder has spaced apart ends 60 and 61 which are connected to opposite ends of the cross portion of a "T", fitting 62.
• the upright portion of the "T" fitting 62 is connected to a supply line 63 which in turn is connected to a pressure fluid source 64.
• a seal 65 supported by the bladder will tend to have a dead zone 66 in the unsupported area between the bladder ends 60 and 61.
• a bridge 67 formed from a rigid material can be inserted in the lower surface of the seal 65 in the dead zone 66. The ends of the bridge 67 are supported by the ends of the bladder 60 and 61 and the pressure applied by the window assembly (not shown) to the seal 65 in the dead zone 66 will be evenly distributed by the bridge 67.
• Many types of fluid can be utilized to inflate the bladder. For example, a relatively non-compressible liquid such as oil could be utilized to fill the bladder.
• the pressure fluid source could be a source of pressurized gas at a relatively higher pressure and include a pressure regulator which could be set to provide the desired pressure to the bladder.
• a compensator can be provided.
• the supply line 63 can be connected to the stem of a "T" fitting 68.
• a cross portion of the "T" fitting 68 can have its ends connected to the pressure fluid source 64 and to a compensator 69.
• the compensator 69 can include a nitrogen filled bag inside a steel cylinder such that excess pressure on the gas in the bladder will tend to compress the nitrogen filled bag and reduce the pressure in the bladder.
• a seal 71 has a curved bottom surface or groove 72 which cooperates with a curved bottom surface 73 formed in a groove 74 in a mold section 75.
• the curved surfaces 72 and 73 conform to an outside surface of a tubular bladder 76.
• a first pair of fins 77 are formed on the surfaces of the seal 71 which face the side walls of the groove 74.
• the fins 77 are angled upwardly toward the opening of the groove and the upper surface of the mold section 75.
• a second pair of fins 78 are formed below the fins 77 and also are angled upwardly toward the opening of the groove 74.
• a third pair of fins 79 are formed at the bottom of the seal and extend in a generally horizontal direction toward the opposing side surfaces of the groove 74. All of the fins 77, 78 and 79 contact the side walls of the groove 74 to maintain the seal 71 in the groove. The fins 77, 78 and 79 tend to prevent the gasket forming material from entering the groove 74. Thus, the tolerances of the seal 71 and the groove 74 do not have to be so precise since the fins will deflect and compensate for any differences in width. As the gasket forming material is injected under pressure, the fins on that side of the seal are placed under pressure which tends to force the fins into even better sealing contact with the walls of the groove. The higher the injection pressure the higher the sealing
• a seal 81 is retained in a groove 82 formed in a mold section 83.
• the seal 81 has an aperture 84 formed parallel to the longitudinal axis thereof.
• the aperture 84 retains a tubular bladder 85.
• the aperture 84 is positioned near the bottom of the seal 81 such that the tubular bladder 85 functions in a manner similar to the tubular bladder 39 shown in Fig. 3. In some instances, the tubular bladder 85 may not be required as the aperture 84 can function as the bladder.
• a seal for sealing between a window assembly and a mold section to define a gasket forming cavity includes a fluid-filled bladder means.
• the seal and the bladder means function together as a dynamic seal to automatically compensate for pressure differentials created by contour differences in the window assembly.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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• 1987
  • 1987-02-19 WO PCT/US1987/000366 patent/WO1987004973A1/en not_active Ceased
  • 1987-02-19 AU AU71207/87A patent/AU7120787A/en not_active Abandoned
  • 1987-02-19 EP EP19870901915 patent/EP0259449A1/de not_active Withdrawn

Non-Patent Citations (1)

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