Bushings, apparatuses including bushings, and associated methods

{
  "publication_number": "US8987612B2",
  "country": "US",
  "kind": "B2",
  "title": "Bushings, apparatuses including bushings, and associated methods",
  "abstract": "Bushings include a tubular body that defines a through-bore for receiving a fastener for mounting a component to an object. The tubular body includes end regions and a plurality of spring elements spaced circumferentially around the tubular body and extending longitudinally along the tubular body between the end regions. Also disclosed are apparatus that include bushings, such as aircraft, and associated methods of utilizing bushings and of manufacturing bushings.",
  "claims": [
    "1. An aircraft assembly, comprising: an aircraft fuel tank constructed of fiber reinforced composite material, wherein the aircraft fuel tank includes a wall that defines a mounting hole; a hydraulic line capable of carrying electrical charges, wherein the hydraulic line extends through the wall of the aircraft fuel tank; a mounting structure for mounting the hydraulic line through the wall of the aircraft fuel tank; a bushing positioned in the mounting hole, wherein the bushing comprises: a tubular body that defines a through-bore, wherein the tubular body is constructed of electrically conductive material that has a conductivity of at least 1×10 6 Siemens per meter, and wherein the tubular body includes: end regions, wherein each end region extends for less than 30% of an overall length of the bushing; and a plurality of spring elements spaced circumferentially around the tubular body and extending longitudinally along the tubular body between the end regions, wherein the spring elements are defined by strips that are contiguous with the end regions and that are not contiguous with circumferentially adjacent portions of the tubular body, and wherein the plurality of spring elements includes a subset of radially inwardly extending spring elements and a subset of radially outwardly extending spring elements, and wherein the radially inwardly extending spring elements and the radially outwardly extending spring elements alternate circumferentially around the tubular body; and a fastener extending through the through-bore of the bushing, wherein the fastener longitudinally compresses the bushing so that the subset of radially inwardly extending spring elements impart inward radial pressure on the fastener and so that the subset of radially outwardly extending spring elements impart outward radial pressure on the wall of the aircraft fuel tank; wherein the bushing provides an electric current flow path between the aircraft fuel tank and the hydraulic line to prevent sparking between the fastener and the aircraft fuel tank during a lightning strike on an aircraft associated with the aircraft assembly.",
    "2. An aircraft assembly, comprising: an aircraft structure constructed of fiber reinforced composite material, wherein the aircraft structure includes a wall that defines a mounting hole; an aircraft component capable of carrying electrical charges, wherein the aircraft component extends through the wall of the aircraft structure; a mounting structure for mounting the aircraft component through the wall of the aircraft structure; a bushing positioned in the mounting hole, wherein the bushing comprises a tubular body that defines a through-bore, wherein the tubular body includes end regions and a plurality of spring elements spaced circumferentially around the tubular body and extending longitudinally along the tubular body between the end regions; and a fastener extending through the through-bore of the bushing, wherein the fastener longitudinally compresses the bushing so that the plurality of spring elements impart radial pressure on the fastener and the wall; wherein the bushing provides an electric current flow path between the aircraft component and the aircraft structure to prevent sparking between the fastener and the aircraft structure.",
    "3. The aircraft assembly of claim 2, wherein the tubular body includes end regions that are flared radially outward.",
    "4. The aircraft assembly of claim 2, wherein spring elements are spaced apart from each other circumferentially around the tubular body.",
    "5. The aircraft assembly of claim 2, wherein the plurality of spring elements includes a plurality of radially inwardly extending spring elements.",
    "6. The aircraft assembly of claim 2, wherein the plurality of spring elements includes a plurality of radially outwardly extending spring elements.",
    "7. The aircraft assembly of claim 2, wherein the plurality of spring elements includes a subset of radially inwardly extending spring elements and a subset of radially outwardly extending spring elements.",
    "8. The aircraft assembly of claim 7, wherein the radially inwardly extending spring elements and the radially outwardly extending spring elements alternate circumferentially around the tubular body.",
    "9. The aircraft assembly of claim 2, wherein the tubular body defines a plurality of longitudinal slits spaced apart circumferentially around the tubular body, and wherein adjacent pairs of slits define the plurality of spring elements.",
    "10. The aircraft assembly of claim 2, wherein the spring elements are leaf springs.",
    "11. The aircraft assembly of claim 2, wherein the tubular body is constructed of a single monolithic piece of material.",
    "12. The aircraft assembly of claim 2, wherein the tubular body defines a longitudinal seam that is not joined together.",
    "13. The aircraft assembly of claim 2, wherein each end region extends for less than 30% of an overall length of the bushing.",
    "14. The aircraft assembly of claim 2, wherein the spring elements are defined by strips that are contiguous with the end regions and that are not contiguous with circumferentially adjacent portions of the tubular body.",
    "15. The aircraft assembly of claim 2, wherein the tubular body is constructed of electrically conductive material that has a conductivity of at least 1×10 6 Siemens per meter.",
    "16. The aircraft assembly of claim 2, wherein when a longitudinal compressive force is applied to the bushing, the bushing has a compressed length that is less than an uncompressed length.",
    "17. The aircraft assembly of claim 2, wherein the aircraft structure includes a fuel tank, and wherein the aircraft component includes a hydraulic line.",
    "18. A method of assembling the aircraft assembly of claim 2, comprising: positioning the bushing in the mounting hole of the aircraft structure; positioning the aircraft component relative to the aircraft structure so that it extends through the wall of the aircraft structure; positioning the fastener through the mounting hole and the through-bore of the bushing; and fastening the aircraft component to the aircraft structure, wherein the fastening includes longitudinally compressing the bushing."
  ],
  "description_excerpt": "The present disclosure relates generally to bushings and more specifically to electrically conductive bushings.\n\nBushings are used for a variety of purposes, and typically, a bushing is a hollow cylindrical component, such as a tube or sleeve, that may be used as a guide or spacer for various tools, fasteners, parts, etc. In some applications, a bushing may form a portion of a bearing assembly. In the aerospace industry, one application for bushings includes ensuring that components that extend through the wall of a fuel tank are sufficiently and electrically grounded to the wall of the fuel tank, so as to avoid sparking. In modern aircraft construction, in which airframes, including fuel tanks, are constructed of carbon fiber reinforced polymers, and when utilizing existing bushing technology, the holes that extend through the wall of a fuel tank and the bushings themselves that are press-fit into the holes are required to have very tight tolerances with respect to each other to ensure proper engagement between, and thus grounding of, the bushings and the wall of the fuel tank. The manufacturing costs associated with these tolerances are not insignificant.\n\nBushings, apparatuses that include bushings, and associated methods are disclosed herein. Bushings according to the present disclosure are configured to be used in the mounting of a component to an object, such as by utilizing a fastener to operatively mount the component to the object.",
  "cpc": [
    "F16L 5/00",
    "B21D 53/00",
    "B32B 37/14",
    "B64D 45/02",
    "F16B 2001/0064",
    "F16B 2200/93",
    "F16B 5/0258",
    "F16B 5/0266",
    "F16F 1/18",
    "F16F 1/26",
    "F16F 1/34",
    "H01R 4/4881",
    "Y10T 29/49947"
  ],
  "ipc": [
    "B32B 37/14",
    "F16B 1/00",
    "F16B 5/02",
    "F16L 5/00",
    "H02G 3/00"
  ],
  "assignees": [
    "BOEING CO"
  ],
  "inventors": [
    "CALLAHAN KEVIN S",
    "FISHER ROBERT EARL",
    "ALVARADO JR SANTIAGO"
  ],
  "filing_date": "2012-11-26",
  "publication_date": "2015-03-24",
  "grant_date": "2015-03-24",
  "priority_date": "2012-11-26",
  "application_number": "US-201213685524-A",
  "family_id": "49674156",
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}