IN-SITU INJECTION MOLDED FASTENER CAP SEAL USING THERMOPLASTIC ELASTOMER MATERIALS

• US 20160136859A1
• Filed: 11/17/2014
• Published: 05/19/2016
• Est. Priority Date: 11/17/2014
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Song, Weidong
• Granted Patent: US 10,035,287 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B05C 17/00516 Shape or geometry of the outlet orifice or the outlet element
• CPC Class Codes: B29C 33/40 Plastics, e.g. foam or rubber
• CPC Class Codes: B29C 33/60 Releasing, lubricating or separating agents in general C10M
• CPC Class Codes: B29C 45/03 Injection moulding apparatus transfer moulding B29C45/02
• CPC Class Codes: B29C 45/036 Injection pistols
• CPC Class Codes: B29C 45/14336 Coating a portion of the article, e.g. the edge of the article B29C45/14573 and B29C45/14598 take precedence
• CPC Class Codes: B29C 45/14467 Joining articles or parts of a single article B29C45/14377, B29C45/14385, B29C45/14581, B29C45/14614 and B29C45/006 take precedence
• CPC Class Codes: B29C 45/14639 for obtaining an insulating effect, e.g. for electrical components
• CPC Class Codes: B29C 45/14819 the inserts being completely encapsulated
• CPC Class Codes: B29K 2021/00 Use of unspecified rubbers as moulding material
• CPC Class Codes: B29K 2021/003 Thermoplastic elastomers
• CPC Class Codes: B29K 2021/006 Thermosetting elastomers
• CPC Class Codes: B29K 2827/18 PTFE, i.e. polytetrafluorethene, e.g. ePTFE, i.e. expanded polytetrafluorethene
• CPC Class Codes: B29K 2905/08 Transition metals
• CPC Class Codes: B29L 2031/3076 Aircrafts blades, propellers B29L2031/08
• CPC Class Codes: B64D 45/02 Lightning protectors; Static dischargers in general H01T
• CPC Class Codes: F16B 33/004 Sealing; Insulation by means of washers F16B43/001
• CPC Class Codes: F16B 37/14 Cap nuts; Nut caps or bolt caps
• CPC Class Codes: F16B 39/021 by injecting a settable material after the screwing down

Abstract

A method for sealing a fastener employs a mold which provided with an inlet port for molding material. The mold is then positioned over a fastener and the mold is sealed against a structure. A molding material is then injected into the mold. The mold is then removed to leave an in-situ molded cap formed over the fastener and sealed to the structure.

Claims

1. A method for sealing a fastener comprising the steps of:

providing a mold having an inlet port for molding material;

positioning the mold over a fastener;

sealing the mold against a structure;

injecting a molding material into the mold; and

,

removing the mold to leave an in-situ formed molded cap over the fastener and sealed to the structure.

2. The method as defined in claim 1 wherein the molding material adheres to the fastener and the structure.

3. The method as defined in claim 1 wherein the mold provides a sealing circumference on a surface of the structure around the fastener, said molded cap sealed to the surface within the sealing circumference.

4. The method as defined in claim 1 wherein the molding material is a thermoplastic elastomer.

5. The method as defined in claim 3 wherein the thermoplastic elastomer is selected from a set of thermoplastic polyether-ester block copolymers, thermoplastic fluoroelastomers, Polyarylsulphones (PSU) or polyphenylsulfones (PPSU).

6. The method as defined in claim 1 wherein the molding material is a thermoset elastomer.

7. The method as defined in claim 6 wherein the thermoset elastomer is selected from a set of Butyl Ethylene Propylene (EPDM), Flouro-carbon (FKM), Neoprene (CR), Nitrile Butadiene (NBR), Silicone (VMQ), Styrene Butadiene (SBR), or Urethane.

8. The method as defined in claim 1 wherein the mold is formed from Polytetrafluoroethylene (PTFE).

9. The method as defined in claim 8 further comprising spraying a release agent into a cavity in the mold prior to positioning the mold.

10. The method as defined in claim 1 further comprising applying a surface treatment to the surface prior to positioning the mold.

11. The method as defined in claim 1 wherein the step of injecting molding material is performed with a handheld gun.

12. The method as defined in claim 1 wherein the steps of applying the mold and sealing the mold are automated.

13. The method as defined in claim 1 wherein the fastener comprises an array of fasteners and the step of positioning the mold comprises positioning the mold over the array of fasteners.

14. A system for in-situ injection molding of a fastener cap comprising:

a mold having

a cavity sized to be received over a fastener in a structure;

an inlet port communication with the cavity to receive a molding material,

a circumferential sealing surface sized to provide a sealing circumference on a surface of the structure surrounding the fastener; and

,

an injection system adapted to provide molding material through the inlet port.

15. The system for in-situ injection molding of a fastener cap as defined in claim 14 wherein the mold incorporates an overflow port.

16. The system for in-situ injection molding of a fastener cap as defined in claim 14 wherein the mold is adapted to receive a thermoplastic elastomer as the molding material.

17. The system for in-situ injection molding of a fastener cap as defined in claim 16 wherein the mold is formed from Polytetrafluoroethylene (PTFE).

18. The system for in-situ injection molding of a fastener cap as defined in claim 16 wherein the mold is formed from stainless steel.

19. A sealing cap for a fastener in a structure comprising:

a molding material formed in-situ in a mold having

a cavity sized to be received over a fastener in a structure;

an inlet port communication with the cavity to receive a molding material and,

a circumferential sealing surface sized to provide a sealing circumference on a surface of the structure surrounding the fastener;

said molding material adhered to the surface and the fastener and sealed to the surface in the sealing circumference.

20. The sealing cap as defined in claim 19 wherein the molding material is a thermoplastic elastomer.