Blind fastener and production method thereof

{
  "publication_number": "US8579566B2",
  "country": "US",
  "kind": "B2",
  "title": "Blind fastener and production method thereof",
  "abstract": "This invention relates to a blind fastener having a hollow sleeve with high surface hardness and sufficient elongation, and to a novel heat treatment method therefor. The method for the heat treatment of the blind fastener includes austempering. The austempering includes a step in which a hollow sleeve of cold-rolled low carbon steel with a carbon percentage of 0.08 to 0.13% is heated and maintained from 800° C. to 950° C. during carburization, and a subsequent step in which isothermal maintenance is performed from 320° C. to 500° C. The resulting carbon percentage (CP) value is from 0.3 to 0.5%. Even in the case of a low carbon steel blind fastener, the austempering can harden the surface of the sleeve and soften the inner portion other than the surface for suitable elongation in order to provide a blind fastener having a sleeve with high surface hardness and sufficient elongation.",
  "claims": [
    "1. A blind fastener, comprising: a hollow sleeve, the hollow sleeve being formed of cold-rolled low carbon steel and subsequently being made with austempering, wherein the austempering includes carburization in a furnace in a gas containing a predetermined amount of carbon monoxide so that the steel has a carbon percentage of from 0.3 to 0.5%.",
    "2. The blind fastener of claim 1, wherein the austempering is performed by heating and maintaining the temperature from 800° C. to 950° C. during carburization, and then performing isothermal maintenance from 320° C. to 500° C."
  ],
  "description_excerpt": "The present invention relates to a blind fastener such as a blind nut or a blind rivet, and to a heat treatment method therefor. More specifically, the present invention relates to the sleeve of a blind fastener and a heat treatment method therefor able to harden the surface and increase the elongation of the hollow sleeve of a blind fastener.\n\nA blind fastener such as a blind nut or a blind rivet has a hollow sleeve with a flange on one end. The sleeve is inserted into a mounting hole in a fastened component such as a panel or another part, and the hollow portion of the sleeve is partially expanded in the outward direction radially so as to interpose the fastened component such as a panel or another part between the expanded portion of the sleeve and the flange of the sleeve. In this way, the fastened component can be securely fastened. When one of the fastened components is a panel and the other fastened component is a part, the part is secured to the panel using a blind fastener. The use of a blind fastener is advantageous because it can be fastened using a blind operation from only one side of the fastened component, even when the fastened component has a wide area such as an automotive panel. The characteristics required of a blind fastener include a hard sleeve in order to obtain high fastening strength, and sufficient elongation when the sleeve is expanded. If the sleeve of the blind fastener does not have sufficient hardness and sufficient elongation, it cannot obtain high fastening strength and may crack when expanded and deformed. In either case, adequate fastening cannot be performed.",
  "cpc": [
    "C21D 1/20",
    "C23C 8/22",
    "F16B 19/1036",
    "F16B 37/067"
  ],
  "ipc": [
    "F16B 13/06"
  ],
  "assignees": [
    "Newfrey LLC"
  ],
  "inventors": [
    "Takanori Makino"
  ],
  "filing_date": "2011-06-13",
  "publication_date": "2013-11-12",
  "grant_date": "2013-11-12",
  "priority_date": "2010-06-17",
  "application_number": "US-201113158977-A",
  "family_id": "44510023",
  "cited_by_count": 0,
  "citations": [
    "US1924099A",
    "US3461771A",
    "EP0158305A1",
    "JPH0372029A",
    "US5181886A",
    "US5860866A",
    "US5722124A",
    "KR19990056686A",
    "US6413326B1",
    "US6318940B1",
    "US20030070736A1",
    "JP2004137560A",
    "US20060147296A1",
    "JP2004286088A",
    "JP2004286217A",
    "US7004845B2",
    "JP2004362154A"
  ]
}