WO2014114909A1 - A protective cap for a fastener - Google Patents

A protective cap for a fastener Download PDF

Info

Publication number
WO2014114909A1
WO2014114909A1 PCT/GB2014/050061 GB2014050061W WO2014114909A1 WO 2014114909 A1 WO2014114909 A1 WO 2014114909A1 GB 2014050061 W GB2014050061 W GB 2014050061W WO 2014114909 A1 WO2014114909 A1 WO 2014114909A1
Authority
WO
WIPO (PCT)
Prior art keywords
protective cap
fastener
sealing portion
induction
exposed end
Prior art date
Application number
PCT/GB2014/050061
Other languages
French (fr)
Inventor
Mark Gill
Original Assignee
Mark Gill
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mark Gill filed Critical Mark Gill
Publication of WO2014114909A1 publication Critical patent/WO2014114909A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B37/00—Nuts or like thread-engaging members
    • F16B37/14—Cap nuts; Nut caps or bolt caps
    • 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
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/36—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction
    • B29C65/3604—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the type of elements heated by induction which remain in the joint
    • B29C65/364—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the type of elements heated by induction which remain in the joint being a woven or non-woven fabric or being a mesh
    • 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
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/36—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction
    • B29C65/3604—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the type of elements heated by induction which remain in the joint
    • B29C65/3644—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the type of elements heated by induction which remain in the joint being a ribbon, band or strip
    • B29C65/3648—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the type of elements heated by induction which remain in the joint being a ribbon, band or strip said strip being perforated
    • 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
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/36—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction
    • B29C65/3604—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the type of elements heated by induction which remain in the joint
    • B29C65/3644—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the type of elements heated by induction which remain in the joint being a ribbon, band or strip
    • B29C65/3652—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" heated by induction characterised by the type of elements heated by induction which remain in the joint being a ribbon, band or strip forming a sleeve, e.g. a wrap-around sleeve
    • 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
    • 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
    • B29C66/13—Single flanged joints; Fin-type joints; Single hem joints; Edge joints; Interpenetrating fingered joints; Other specific particular designs of joint cross-sections not provided for in groups B29C66/11 - B29C66/12
    • B29C66/131—Single flanged joints, i.e. one of the parts to be joined being rigid and flanged in the joint area
    • 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
    • B29C66/20—Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines
    • B29C66/24—Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines said joint lines being closed or non-straight
    • B29C66/242—Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines said joint lines being closed or non-straight said joint lines being closed, i.e. forming closed contours
    • B29C66/2422—Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines said joint lines being closed or non-straight said joint lines being closed, i.e. forming closed contours being circular, oval or elliptical
    • B29C66/24221—Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines said joint lines being closed or non-straight said joint lines being closed, i.e. forming closed contours being circular, oval or elliptical being circular
    • 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
    • B29C66/47—Joining single elements to sheets, plates or other substantially flat surfaces
    • B29C66/474—Joining single elements to sheets, plates or other substantially flat surfaces said single elements being substantially non-flat
    • 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
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/72—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined
    • B29C66/721—Fibre-reinforced materials
    • 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
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/73—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/739—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/7392—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic
    • 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
    • B29C66/8141—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 surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined
    • B29C66/81431—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 surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined comprising a single cavity, e.g. a groove
    • 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
    • B29C66/83—General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools
    • B29C66/832—Reciprocating joining or pressing tools
    • B29C66/8322—Joining or pressing tools reciprocating along one axis
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B33/00—Features common to bolt and nut
    • F16B33/004—Sealing; Insulation
    • 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
    • B29C66/349—Cooling the welding zone on the welding spot
    • B29C66/3494—Cooling the welding zone on the welding spot while keeping the welding zone under 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
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/53—Joining single elements to tubular articles, hollow articles or bars
    • B29C66/532—Joining single elements to the wall of tubular articles, hollow articles or bars
    • 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
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts 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
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/72—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined
    • B29C66/721—Fibre-reinforced materials
    • B29C66/7212—Fibre-reinforced materials characterised by the composition of the fibres
    • 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
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/73—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/731—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the intensive physical properties of the material of the parts to be joined
    • B29C66/7311—Thermal properties
    • B29C66/73117—Tg, i.e. glass transition temperature
    • B29C66/73118—Tg, i.e. glass transition temperature of different glass transition temperature, i.e. the glass transition temperature of one of the parts to be joined being different from the glass transition temperature of the other part
    • 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
    • B29L2001/00—Articles provided with screw threads
    • 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
    • B29L2031/3076—Aircrafts
    • 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
    • B29L2031/3076—Aircrafts
    • B29L2031/3085—Wings
    • 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
    • B29L2031/7172—Fuel tanks, jerry cans

Definitions

  • the present disclosure relates generally to a protective cap for a fastener and/or to a method for protecting a fastener using a protective cap.
  • Embodiments of the present disclosure provide a protective cap and an associated method for protecting an exposed end of a fastener.
  • the exposed ends of the fasteners inside the fuel tanks are coated with an insulating sealant material.
  • the sealant material contains any sparks and essentially acts as a barrier between the exposed ends of the fasteners and fuel or fuel vapour.
  • the sealant material has a limited shelf life and is difficult to work with.
  • a typical solution to this problem is to locate a protective cap over the exposed end of the fastener.
  • the present disclosure aims to provide a protective cap which can be used to protect an exposed end of a fastener in a variety of situations including, but not limited to, those described above.
  • a protective cap for a fastener according to claim 1.
  • a fastening assembly according to claim 17.
  • a structural component according to claim 20 may be a composite structural component fabricated from composite material.
  • an aircraft comprising a structural component according to claim 22.
  • a method for protecting a fastener according to claim 23 there is provided a method for protecting a fastener according to claim 23.
  • the protective cap according to the present disclosure can be fitted quickly and easily over an exposed end of a fastener.
  • the induction heatable element heats up rapidly in the presence of an induction field, in turn rapidly heating the sealing portion and allowing the protective cap to be secured in position.
  • the protective cap may be configured to protect an end of a fastener protruding from a surface, for example inside a composite aircraft wing structure.
  • the cover portion may include a cavity for receiving an end of a fastener protruding from a surface.
  • the cover portion may include a rim.
  • the sealing portion may comprise a sealing ring which may extend continuously around the rim of the cover portion.
  • the sealing portion may be bonded to the cover portion.
  • the induction heatable element may be located between the cover portion and the sealing portion, for example in a circumferentially extending recess.
  • the induction heatable element may be located adjacent to the sealing portion and may be in contact with the sealing portion. This may facilitate the transfer of heat from the induction heatable element to the sealing portion, thereby minimising the time taken for the sealing portion to heat up.
  • the cover portion may comprise an electrically insulating material.
  • the sealing portion may comprise an electrically insulating material.
  • the cover portion may comprise a chemically resistant material.
  • the sealing portion may comprise a chemically resistant material. The use of such materials may be particularly advantageous when the protective cap is used as a lightning protection device in a composite aircraft structure or as a corrosion protection device.
  • the cover portion may comprise a first thermoplastic material.
  • the first thermoplastic material may be polyetherimide (PEI) or polyether ether ketone (PEEK).
  • the sealing portion may comprise a second thermoplastic material.
  • the first thermoplastic material may have a glass transition temperature which is higher than the glass transition temperature of the second thermoplastic material. This ensures that when the induction heatable element is heated to a temperature which is sufficiently high to soften or melt the sealing portion, the cover portion does not soften or melt and its structural integrity is maintained.
  • the sealing portion could comprise a heat-activated adhesive.
  • the induction heatable element may comprise an induction heatable ring.
  • the induction heatable element may be permeable.
  • the permeable structure could be provided by apertures extending through the induction heatable element or by a woven structure.
  • a permeable structure would allow adhesive material (e.g. formed due to softening or melting of the sealing portion and/or heat-activated adhesive) to flow through the induction heatable element and thereby increase the contact area between the adhesive material and the cover portion. This would in turn improve the bond strength between the cover portion and the surface around the exposed end of the fastener.
  • the protective cap may comprise a retaining arrangement which in one implementation urges the sealing portion into contact with the surface around the exposed end of the fastener.
  • the retaining arrangement provides a number of advantages. Firstly, it applies a predetermined force to the sealing portion thereby ensuring that an optimum seal is formed with the surface around the exposed end of the fastener during inductive heating and subsequent cooling. Secondly, it acts as a supplementary retaining feature to hold the protective cap in position. The stress on the adhesive bond between the cover portion and the surface around the exposed end of the fastener is thereby reduced. Further, in the unlikely event that the adhesive bond fails, the protective cap is still retained in position.
  • the retaining arrangement may cooperate in use with part of the fastener.
  • the retaining arrangement may comprise a plurality of circumferentially spaced retaining lugs.
  • the retaining lugs may project from the cover portion and may project inwardly towards the fastener for cooperation with part of the fastener.
  • part of the fastener includes a retaining groove in which the retaining lugs are engaged in use.
  • the fastener may advantageously comprise a washer in which the retaining groove is formed.
  • the retaining groove could of course be formed in the end of the fastener that protrudes from the surface, for example in the head of the fastener.
  • the retaining lugs may be resiliently deformable so that they can flex or otherwise deform and then snap into the retaining groove as the protective cap is pressed into position over the exposed end of the fastener.
  • the protection method according to the fifth aspect of the present disclosure may comprise activating an induction heater to inductively heat the induction heatable element and may comprise thereafter deactivating the induction heater to allow the induction heatable element to cool.
  • the induction heatable element heats up, heat is transferred to the sealing portion causing it to soften or melt.
  • the induction heatable element, and hence the sealing portion cool down. The sealing portion thus hardens and adheres to the surface around the exposed end of the fastener.
  • the method may comprise locating an induction sealing head incorporating an induction coil over the protective cap to effect inductive heating of the induction heatable element upon activation of the induction heater.
  • the sealing portion may be urged into contact with the surface around the exposed end of the fastener.
  • the sealing portion may be urged into contact with the surface around the exposed end of the fastener at least during inductive heating of the induction heatable element and during cooling of the induction heatable element, for example after the induction heater has been deactivated. As explained above, this ensures that the sealing portion is properly adhered to the surface around the exposed end of the fastener.
  • the sealing portion may be urged into contact with the surface around the exposed end of the fastener using the induction sealing head.
  • the induction sealing head which is typically a component of the induction heater, provides an effective means for securing the protective cap in position.
  • the sealing portion may be urged into contact with the surface around the exposed end of the fastener using a retaining arrangement which may be as described above.
  • Figure 1 is a diagrammatic cross-sectional view of a protective cap according to one embodiment of the present disclosure
  • Figure 2 is a diagrammatic cross-sectional view of the protective cap shown in Figure 1 positioned over an exposed end of a fastener;
  • Figure 3 is a diagrammatic view of an induction heater
  • Figure 4a is a diagrammatic perspective view from beneath a protective cap with part of the sealing portion removed to expose a permeable induction heatable element
  • Figure 4b is a diagrammatic top view of the permeable induction heatable element of Figure 4a;
  • Figure 5 is a diagrammatic top view of an alternative permeable induction heatable element
  • Figure 6a is a diagrammatic cross-sectional view of a protective cap according to another embodiment of the present disclosure.
  • Figure 6b is a diagrammatic cross-sectional view of the protective cap shown in Figure 6a positioned over an exposed end of a fastener;
  • Figure 7 is a diagrammatic perspective view from beneath the protective cap shown in Figures 6a and 6b.
  • FIG. 2 there is shown part of a structural component comprising a composite panel 10, for example formed of carbon fibre reinforced plastics (CFRP), and a metallic fastener 12 extending through the panel 10.
  • CFRP carbon fibre reinforced plastics
  • an end of the fastener 12 protrudes from a surface 14 of the panel 10.
  • Figures 1 and 2 both illustrate a protective cap 16 for enclosing and protecting the end of the fastener 12.
  • the protective cap 16 comprises a dome-shaped cover portion 18 and a sealing portion 20.
  • the cover portion 18 includes a cavity 22 thus enabling the cover portion 18 to be located over the protruding end of the fastener 12.
  • the cover portion 18 includes a rim 24 which is enlarged in the radially outward direction to provide a shoulder portion 26.
  • the cover portion 18 and the sealing portion 20 are formed respectively from first and second thermoplastic materials, with the first thermoplastic material having a higher glass transition temperature than the second thermoplastic material.
  • the cover portion 18 is formed from polyetherimide (PEI).
  • PEI polyetherimide
  • the sealing portion 20 is typically bonded to the cover portion 18 but it may be attached in any suitable manner.
  • An induction heatable element in the form of an induction heatable ring 28 is provided in a circumferentially extending recess 30 between the cover portion 18 and the sealing portion 20 so that the induction heatable ring 28 is located adjacent to, and in contact with, the sealing portion 20.
  • the induction heatable ring 28 comprises any suitable material that heats up in the presence of an induction field.
  • An induction heater 32 shown generally in Figure 3, can be used to secure the protective cap 16 in position over the exposed end of the fastener 12.
  • the induction heater 32 includes a generator unit 34 and an induction sealing head 36 incorporating an induction coil 38.
  • the induction sealing head 36 includes a cavity 40 which is suitably dimensioned to receive the protective cap 16.
  • the protective cap 16 could be located in the cavity 40 before the protective cap 16 is positioned over the protruding end of the fastener 12. In this case, it will be understood that the induction sealing head 36 is used to position the protective cap 16 over the protruding end of the fastener 12. Alternatively, the protective cap 16 could be positioned over the protruding end of the fastener 12 before the induction sealing head 36 is pushed onto the protective cap 16. In both cases, the protective cap 16 must be correctly located over the exposed end of the fastener 12 so that the protruding exposed end is received within the cavity 22 and so that the sealing portion 20 contacts the surface 14 of the panel 10 around the end of the fastener 12.
  • a force is applied to the protective cap 16 using the induction sealing head 36 to urge the sealing portion 20 into contact with the surface 14 of the panel 10 around the fastener 12.
  • part of it may contact the shoulder portion 26 so that force is applied directly to the sealing portion 20 to urge it into contact with the surface 14.
  • the induction heater 32 is activated so that an induction field 42 is generated in the vicinity of the induction coil 38, as shown diagrammatically by the magnetic field or flux lines in Figure 2.
  • the induction field 42 causes the induction heatable ring 28 to heat up and the heat is transferred, typically by conduction, into the sealing portion 20 and the cover portion 18.
  • the structural integrity of the cover portion 18 is not affected because the first thermoplastic material from which it is formed is sufficiently temperature resistant.
  • the glass transition temperature of the first thermoplastic material is higher than that of the second thermoplastic material from which the sealing portion 20 is formed.
  • the sealing portion 20 softens to become a molten or rubberlike material with adhesive properties whilst the cover portion 18 does not.
  • the sealing portion 20 could alternatively or additionally comprise a heat-activated adhesive.
  • the induction heater 32 is subsequently deactivated and this allows the induction heatable ring 28 to cool.
  • the sealing portion 20 also cools and in doing so adheres to the surface 14 of the panel 10.
  • the induction sealing head 36 is used to apply a force to the protective cap 16 to press the sealing portion 20 against the surface 14 of the panel 10
  • the force may be maintained during the cooling phase to ensure that the sealing portion 20 fully adheres to the surface 14 of the panel 10.
  • the induction sealing head 36 can be removed from the protective cap 16 and used to secure further protective caps 16 in position.
  • the induction sealing head 36 typically includes pressure sensors and/or load cells which enable the force applied to the sealing portion 20 to be measured in real-time. This provides assurance that the correct force has been applied to the sealing portion 20 for optimum bonding to the surface 14 of the panel 10.
  • the protective cap 16 includes a retaining arrangement 48 which biases the sealing portion 20 into contact with the surface 14 of the panel 10 around the exposed end of the fastener 12.
  • the retaining arrangement 48 comprises a plurality of retaining lugs 50 which are spaced circumferentially around an inner surface of the cover portion 18.
  • the retaining lugs 50 are resiliently deformable and locate in a circumferential retaining groove 52 provided in a retaining washer 54.
  • the retaining lugs 50 are formed integrally with the cover portion 18.
  • the induction heatable ring 28 can have a permeable structure to enable adhesive material which is generated upon heating the sealing portion 20 to flow in both directions and improve the bond strength between the cover portion 18 and the surface 14 of the panel 10 around the fastener 12.
  • the permeable structure can be provided by a plurality of apertures 44.
  • the permeable structure can be provided by a woven construction 46.
  • the structural component illustrated in Figures 2 and 6b comprises only a single panel 10, it should be understood that the structural component may be a stacked laminate structure which employs a plurality of composite panels 10 and a plurality of fasteners 12. This would typically be the case in a composite aircraft structure such as a wing section.
  • the protective cap 16 may be used with any type of fastener formed of any type of material.

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  • Engineering & Computer Science (AREA)
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  • General Engineering & Computer Science (AREA)
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  • Lining Or Joining Of Plastics Or The Like (AREA)

Abstract

A protective cap (16) for a fastener (12) comprises a cover portion (18) locatable over an exposed end of a fastener (12) and a sealing portion (20) contactable with a surface (14) around the exposed end of the fastener (12). The protective cap (16) further comprises an induction heatable element (28) which is arranged to heat the sealing portion (20) to enable it to adhere to the surface (14).

Description

A PROTECTIVE CAP FOR A FASTENER
Technical Field
The present disclosure relates generally to a protective cap for a fastener and/or to a method for protecting a fastener using a protective cap. Embodiments of the present disclosure provide a protective cap and an associated method for protecting an exposed end of a fastener.
Technical Background
There are many situations in which it may be desirable to protect an exposed end of a fastener.
One such situation is when metallic fasteners are used to secure together structural components of an aircraft that are fabricated using composite materials such as carbon fibre reinforced plastics (CFRP). Metallic fasteners are highly electrically conductive whereas composite aircraft structures have a high electrical resistance in comparison to more conventional aluminium structures. There is, therefore, an increased risk of spark generation at the exposed ends of fasteners in composite aircraft structures in the event of a lightning strike. This can be especially problematic when metallic fasteners are used in composite aircraft wing sections, which also serve as the fuel tanks, because of the dangers associated with ignition of fuel or fuel vapour inside the fuel tanks.
Various techniques have been proposed to improve lightning protection for fasteners in composite aircraft wing structures. In one commonly employed technique, the exposed ends of the fasteners inside the fuel tanks are coated with an insulating sealant material. The sealant material contains any sparks and essentially acts as a barrier between the exposed ends of the fasteners and fuel or fuel vapour. However, the sealant material has a limited shelf life and is difficult to work with.
Another common situation in which it is desirable to protect an exposed end of a fastener is when the fastener is used in a corrosive environment, to prevent corrosion of the fastener. A typical solution to this problem is to locate a protective cap over the exposed end of the fastener.
The present disclosure aims to provide a protective cap which can be used to protect an exposed end of a fastener in a variety of situations including, but not limited to, those described above.
Summary of the Disclosure
According to a first aspect of the present disclosure, there is provided a protective cap for a fastener according to claim 1.
According to a second aspect of the present disclosure, there is provided a fastening assembly according to claim 17. According to a third aspect of the present disclosure, there is provided a structural component according to claim 20. The structural component may be a composite structural component fabricated from composite material.
According to a fourth aspect of the present disclosure, there is provided an aircraft comprising a structural component according to claim 22.
According to a fifth aspect of the present disclosure, there is provided a method for protecting a fastener according to claim 23. The protective cap according to the present disclosure can be fitted quickly and easily over an exposed end of a fastener. Advantageously, the induction heatable element heats up rapidly in the presence of an induction field, in turn rapidly heating the sealing portion and allowing the protective cap to be secured in position. The protective cap may be configured to protect an end of a fastener protruding from a surface, for example inside a composite aircraft wing structure. Accordingly, the cover portion may include a cavity for receiving an end of a fastener protruding from a surface. The cover portion may include a rim. The sealing portion may comprise a sealing ring which may extend continuously around the rim of the cover portion. The sealing portion may be bonded to the cover portion. The induction heatable element may be located between the cover portion and the sealing portion, for example in a circumferentially extending recess.
The induction heatable element may be located adjacent to the sealing portion and may be in contact with the sealing portion. This may facilitate the transfer of heat from the induction heatable element to the sealing portion, thereby minimising the time taken for the sealing portion to heat up.
The cover portion may comprise an electrically insulating material. The sealing portion may comprise an electrically insulating material. The cover portion may comprise a chemically resistant material. The sealing portion may comprise a chemically resistant material. The use of such materials may be particularly advantageous when the protective cap is used as a lightning protection device in a composite aircraft structure or as a corrosion protection device. The cover portion may comprise a first thermoplastic material. The first thermoplastic material may be polyetherimide (PEI) or polyether ether ketone (PEEK). The sealing portion may comprise a second thermoplastic material. The first thermoplastic material may have a glass transition temperature which is higher than the glass transition temperature of the second thermoplastic material. This ensures that when the induction heatable element is heated to a temperature which is sufficiently high to soften or melt the sealing portion, the cover portion does not soften or melt and its structural integrity is maintained.
The sealing portion could comprise a heat-activated adhesive.
The induction heatable element may comprise an induction heatable ring. The induction heatable element may be permeable. The permeable structure could be provided by apertures extending through the induction heatable element or by a woven structure. A permeable structure would allow adhesive material (e.g. formed due to softening or melting of the sealing portion and/or heat-activated adhesive) to flow through the induction heatable element and thereby increase the contact area between the adhesive material and the cover portion. This would in turn improve the bond strength between the cover portion and the surface around the exposed end of the fastener.
The protective cap may comprise a retaining arrangement which in one implementation urges the sealing portion into contact with the surface around the exposed end of the fastener. The retaining arrangement provides a number of advantages. Firstly, it applies a predetermined force to the sealing portion thereby ensuring that an optimum seal is formed with the surface around the exposed end of the fastener during inductive heating and subsequent cooling. Secondly, it acts as a supplementary retaining feature to hold the protective cap in position. The stress on the adhesive bond between the cover portion and the surface around the exposed end of the fastener is thereby reduced. Further, in the unlikely event that the adhesive bond fails, the protective cap is still retained in position. The retaining arrangement may cooperate in use with part of the fastener. It is, therefore, particularly but not exclusively suitable for use with a fastener having an end which protrudes from a surface. The retaining arrangement may comprise a plurality of circumferentially spaced retaining lugs. The retaining lugs may project from the cover portion and may project inwardly towards the fastener for cooperation with part of the fastener.
In the fastening assembly according to the second aspect, part of the fastener includes a retaining groove in which the retaining lugs are engaged in use. The fastener may advantageously comprise a washer in which the retaining groove is formed. The retaining groove could of course be formed in the end of the fastener that protrudes from the surface, for example in the head of the fastener. The retaining lugs may be resiliently deformable so that they can flex or otherwise deform and then snap into the retaining groove as the protective cap is pressed into position over the exposed end of the fastener.
The protection method according to the fifth aspect of the present disclosure may comprise activating an induction heater to inductively heat the induction heatable element and may comprise thereafter deactivating the induction heater to allow the induction heatable element to cool. As the induction heatable element heats up, heat is transferred to the sealing portion causing it to soften or melt. After the induction heater has been deactivated, the induction heatable element, and hence the sealing portion, cool down. The sealing portion thus hardens and adheres to the surface around the exposed end of the fastener.
The method may comprise locating an induction sealing head incorporating an induction coil over the protective cap to effect inductive heating of the induction heatable element upon activation of the induction heater.
The sealing portion may be urged into contact with the surface around the exposed end of the fastener.
The sealing portion may be urged into contact with the surface around the exposed end of the fastener at least during inductive heating of the induction heatable element and during cooling of the induction heatable element, for example after the induction heater has been deactivated. As explained above, this ensures that the sealing portion is properly adhered to the surface around the exposed end of the fastener.
In one implementation, the sealing portion may be urged into contact with the surface around the exposed end of the fastener using the induction sealing head. The induction sealing head, which is typically a component of the induction heater, provides an effective means for securing the protective cap in position. In another implementation, the sealing portion may be urged into contact with the surface around the exposed end of the fastener using a retaining arrangement which may be as described above. Brief Description of the Drawings
Figure 1 is a diagrammatic cross-sectional view of a protective cap according to one embodiment of the present disclosure;
Figure 2 is a diagrammatic cross-sectional view of the protective cap shown in Figure 1 positioned over an exposed end of a fastener;
Figure 3 is a diagrammatic view of an induction heater;
Figure 4a is a diagrammatic perspective view from beneath a protective cap with part of the sealing portion removed to expose a permeable induction heatable element; Figure 4b is a diagrammatic top view of the permeable induction heatable element of Figure 4a;
Figure 5 is a diagrammatic top view of an alternative permeable induction heatable element;
Figure 6a is a diagrammatic cross-sectional view of a protective cap according to another embodiment of the present disclosure;
Figure 6b is a diagrammatic cross-sectional view of the protective cap shown in Figure 6a positioned over an exposed end of a fastener; and
Figure 7 is a diagrammatic perspective view from beneath the protective cap shown in Figures 6a and 6b.
Detailed Description of Embodiments
Embodiments of the present disclosure will now be described by way of example only and with reference to the accompanying drawings.
Referring initially to Figure 2, there is shown part of a structural component comprising a composite panel 10, for example formed of carbon fibre reinforced plastics (CFRP), and a metallic fastener 12 extending through the panel 10. In the illustrated example, an end of the fastener 12 protrudes from a surface 14 of the panel 10. It should, however, be understood that the present disclosure is not limited to such arrangements and is equally applicable to arrangements in which an end of the fastener 12 is flush with the surface 14 of the panel 10 or even recessed slightly from the surface 14 of the panel 10. Figures 1 and 2 both illustrate a protective cap 16 for enclosing and protecting the end of the fastener 12. The protective cap 16 comprises a dome-shaped cover portion 18 and a sealing portion 20. The cover portion 18 includes a cavity 22 thus enabling the cover portion 18 to be located over the protruding end of the fastener 12. The cover portion 18 includes a rim 24 which is enlarged in the radially outward direction to provide a shoulder portion 26.
The cover portion 18 and the sealing portion 20 are formed respectively from first and second thermoplastic materials, with the first thermoplastic material having a higher glass transition temperature than the second thermoplastic material. In typical embodiments, the cover portion 18 is formed from polyetherimide (PEI). The sealing portion 20 is typically bonded to the cover portion 18 but it may be attached in any suitable manner.
An induction heatable element in the form of an induction heatable ring 28 is provided in a circumferentially extending recess 30 between the cover portion 18 and the sealing portion 20 so that the induction heatable ring 28 is located adjacent to, and in contact with, the sealing portion 20. The induction heatable ring 28 comprises any suitable material that heats up in the presence of an induction field. An induction heater 32, shown generally in Figure 3, can be used to secure the protective cap 16 in position over the exposed end of the fastener 12. The induction heater 32 includes a generator unit 34 and an induction sealing head 36 incorporating an induction coil 38. The induction sealing head 36 includes a cavity 40 which is suitably dimensioned to receive the protective cap 16. The protective cap 16 could be located in the cavity 40 before the protective cap 16 is positioned over the protruding end of the fastener 12. In this case, it will be understood that the induction sealing head 36 is used to position the protective cap 16 over the protruding end of the fastener 12. Alternatively, the protective cap 16 could be positioned over the protruding end of the fastener 12 before the induction sealing head 36 is pushed onto the protective cap 16. In both cases, the protective cap 16 must be correctly located over the exposed end of the fastener 12 so that the protruding exposed end is received within the cavity 22 and so that the sealing portion 20 contacts the surface 14 of the panel 10 around the end of the fastener 12. In one implementation, a force is applied to the protective cap 16 using the induction sealing head 36 to urge the sealing portion 20 into contact with the surface 14 of the panel 10 around the fastener 12. Depending on the configuration of the induction sealing head 36, part of it may contact the shoulder portion 26 so that force is applied directly to the sealing portion 20 to urge it into contact with the surface 14.
Once the protective cap 16 and induction sealing head 36 are correctly positioned as explained above, the induction heater 32 is activated so that an induction field 42 is generated in the vicinity of the induction coil 38, as shown diagrammatically by the magnetic field or flux lines in Figure 2. The induction field 42 causes the induction heatable ring 28 to heat up and the heat is transferred, typically by conduction, into the sealing portion 20 and the cover portion 18. The structural integrity of the cover portion 18 is not affected because the first thermoplastic material from which it is formed is sufficiently temperature resistant. Importantly, the glass transition temperature of the first thermoplastic material is higher than that of the second thermoplastic material from which the sealing portion 20 is formed. Thus, as heat from the induction heatable ring 28 is conducted into both the cover portion 18 and the sealing portion 20, the sealing portion 20 softens to become a molten or rubberlike material with adhesive properties whilst the cover portion 18 does not. The sealing portion 20 could alternatively or additionally comprise a heat-activated adhesive. The induction heater 32 is subsequently deactivated and this allows the induction heatable ring 28 to cool. The sealing portion 20 also cools and in doing so adheres to the surface 14 of the panel 10. In implementations in which the induction sealing head 36 is used to apply a force to the protective cap 16 to press the sealing portion 20 against the surface 14 of the panel 10, the force may be maintained during the cooling phase to ensure that the sealing portion 20 fully adheres to the surface 14 of the panel 10. Finally, the induction sealing head 36 can be removed from the protective cap 16 and used to secure further protective caps 16 in position. The induction sealing head 36 typically includes pressure sensors and/or load cells which enable the force applied to the sealing portion 20 to be measured in real-time. This provides assurance that the correct force has been applied to the sealing portion 20 for optimum bonding to the surface 14 of the panel 10.
Referring to Figures 6 and 7, in another implementation the protective cap 16 includes a retaining arrangement 48 which biases the sealing portion 20 into contact with the surface 14 of the panel 10 around the exposed end of the fastener 12. The retaining arrangement 48 comprises a plurality of retaining lugs 50 which are spaced circumferentially around an inner surface of the cover portion 18. The retaining lugs 50 are resiliently deformable and locate in a circumferential retaining groove 52 provided in a retaining washer 54. The retaining lugs 50 are formed integrally with the cover portion 18.
In their normal, unstressed, position shown in Figures 6a and 7, the retaining lugs 50 project inwardly from the inner surface of the cover portion 18 and downwardly towards the surface 14 of the panel 10. As the protective cap 16 is pressed into position over the exposed end of the fastener 12, the retaining lugs 50 are flexed upwardly due to contact with the washer 54 until they snap into the retaining groove 52 as shown in Figure 6b. The cooperation between the retaining lugs 50 and the retaining groove 52 presses the sealing portion 20 into contact with the surface 14 of the panel 10. An optimal biasing force is, thus, applied by the retaining lugs 50 to the sealing portion 20 during induction heating and as a result it is generally not necessary to apply a force to the protective cap 16 using the induction sealing head 36. The induction sealing head 36 is still, of course, positioned over the protective cap 16 as explained above so that the induction heater 32 can generate an induction field 42 in the vicinity of the induction heatable ring 28 and cause it to heat up. It will, of course, be appreciated that the cooperation between the retaining lugs 50 and the retaining groove 52 continues to press the sealing portion 20 into contact with the surface 14 of the panel 10 even after the sealing portion 20 has been adhered to the surface 14 of the panel 10. This provides a number of advantages as discussed earlier in this specification.
The induction heatable ring 28 can have a permeable structure to enable adhesive material which is generated upon heating the sealing portion 20 to flow in both directions and improve the bond strength between the cover portion 18 and the surface 14 of the panel 10 around the fastener 12. As shown in Figures 4a and 4b, the permeable structure can be provided by a plurality of apertures 44. Alternatively, and as shown in Figure 5, the permeable structure can be provided by a woven construction 46.
Although exemplary embodiments have been described in the preceding paragraphs, it should be understood that various modifications may be made to those embodiments without departing from the scope of the appended claims. Thus, the breadth and scope of the claims should not be limited to the above-described exemplary embodiments. Each feature disclosed in the specification, including the claims and drawings, may be replaced by alternative features serving the same, equivalent or similar purposes, unless expressly stated otherwise.
For example, although the structural component illustrated in Figures 2 and 6b comprises only a single panel 10, it should be understood that the structural component may be a stacked laminate structure which employs a plurality of composite panels 10 and a plurality of fasteners 12. This would typically be the case in a composite aircraft structure such as a wing section. The protective cap 16 may be used with any type of fastener formed of any type of material.
Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".
Any combination of the above-described features in all possible variations thereof is encompassed by the present invention as claimed unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

Claims
1. A protective cap for a fastener, the protective cap comprising:
a cover portion locatable over an exposed end of a fastener;
a sealing portion contactable with a surface around the exposed end of the fastener; and
an induction heatable element which is arranged to heat the sealing portion to enable it to adhere to the surface.
2. A protective cap according to claim 1, wherein the cover portion includes a cavity for receiving an end of a fastener protruding from a surface.
3. A protective cap according to claim 1 or claim 2, wherein the sealing portion comprises a sealing ring which extends continuously around a rim of the cover portion.
4. A protective cap according to any preceding claim, wherein the induction heatable element is located between the cover portion and the sealing portion.
5. A protective cap according to claim 4, wherein the induction heatable element is located in a circumferentially extending recess.
6. A protective cap according to any preceding claim, wherein the induction heatable element is located adjacent to, and in contact with, the sealing portion.
7. A protective cap according to any preceding claim, wherein the induction heatable element comprises an induction heatable ring.
8. A protective cap according to any preceding claim, wherein the induction heatable element comprises a permeable structure.
9. A protective cap according to any preceding claim, wherein one or both of the cover portion and the sealing portion comprise an electrically insulating material.
10. A protective cap according to any preceding claim, wherein one or both of the cover portion and the sealing portion comprise a chemically resistant material.
11. A protective cap according to any preceding claim, wherein the cover portion comprises a first thermoplastic material and the sealing portion comprises a second thermoplastic material.
12. A protective cap according to claim 11, wherein the first thermoplastic material has a glass transition temperature which is higher than the glass transition temperature of the second thermoplastic material.
13. A protective cap according to any preceding claim, wherein the sealing portion comprises a heat-activated adhesive.
14. A protective cap according to any preceding claim, wherein the protective cap comprises a retaining arrangement which urges the sealing portion into contact with the surface around the exposed end of the fastener.
15. A protective cap according to claim 14, wherein the retaining arrangement cooperates in use with part of the fastener.
16. A protective cap according to claim 15, wherein the retaining arrangement comprises a plurality of circumferentially spaced retaining lugs which project from the cover portion inwardly towards the fastener.
17. A fastening assembly comprising a fastener having an exposed end and a protective cap according to claim 16 located over the exposed end with its sealing portion in contact with a surface around the exposed end, wherein part of the fastener includes a retaining groove in which said retaining lugs are engaged in use.
18. A fastening assembly according to claim 17, wherein the retaining lugs are resiliently deformable to permit said engagement in the retaining groove.
19. A fastening assembly according to claim 17 or claim 18, wherein the fastener comprises a washer in which said retaining groove is formed.
20. A structural component comprising a fastener and a protective cap according to any of claims 1 to 16 located over an exposed end of the fastener.
21. A structural component according to claim 20, wherein the structural component is a composite structural component fabricated from composite material.
22. An aircraft comprising a structural component according to claim 20 or claim 21.
23. A method for protecting a fastener using a protective cap according to any of claims 1 to 16, the method comprising:
locating the cover portion over the exposed end of the fastener so that the sealing portion is in contact with the surface around the exposed end; and
inductively heating the induction heatable element to heat the sealing portion and adhere it to the surface.
24. A method according to claim 23, wherein the method comprises activating an induction heater to inductively heat the induction heatable element and thereafter deactivating the induction heater to allow the induction heatable element to cool.
25. A method according to claim 23 or claim 24, wherein the method comprises locating an induction sealing head incorporating an induction coil over the protective cap to inductively heat the induction heatable element.
26. A method according to any of claims 23 to 25, wherein the sealing portion is urged into contact with the surface around the exposed end of the fastener.
27. A method according to claim 26, wherein the method comprises urging the sealing portion into contact with the surface around the exposed end of the fastener during inductive heating of the induction heatable element and during cooling of the induction heatable element.
28. A method according to claims 25 and 26 or claims 25, 26 and 27, wherein the method comprises urging the sealing portion into contact with the surface around the exposed end of the fastener using the induction sealing head.
29. A method according to claim 26, wherein the method comprises urging the sealing portion into contact with the surface around the exposed end of the fastener using a retaining arrangement.
PCT/GB2014/050061 2013-01-24 2014-01-10 A protective cap for a fastener WO2014114909A1 (en)

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GB1301267.9A GB2510131B (en) 2013-01-24 2013-01-24 A protective cap for a fastener

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GB201301267D0 (en) 2013-03-06
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