Pinned airfoil propeller assembly

{
  "publication_number": "US5102300A",
  "country": "US",
  "kind": "A",
  "title": "Pinned airfoil propeller assembly",
  "abstract": "A propeller or fan blade is rotatably mounted to a blade retention pitch member by a pin radially outside of a spinner. By mounting the propeller blade for rotation about the axis of the pin, the blade response to a vibratory excitation in a first mode of vibration is modified such that the twisting motion of the blade is minimized. High speed stability of the blade is enhanced thereby. Moreover a damaged blade may be easily replaced.",
  "claims": [
    "1. A propeller assembly having a hub, a pitch member attaching to said hub, a propeller or fan blade attaching to said pitch member and a spinner for covering said hub, wherein the improvement comprises; means for rotatably attaching said propeller or fan blade to said pitch member radially outwardly from said spinner such that said propeller or fan blade may be readily removed from said pitch member without disassembling said pitch member, said hub or said spinner and for effectively modifying a response of said blade to the vibratory excitation in the first mode of vibration such that a twisting motion of the blade is minimized.",
    "2. The propeller assembly of claim 1 wherein said means for rotatably attaching and for decoupling comprises; means extending from said pitch member for attaching to said blade, said means having a first opening therethrough, a recess disposed within said blade for cooperating with said means extending from said pitch member, a second opening extending through a root portion of said blade, and a means extending through said first and second openings and said recess for attaching said blade to said member.",
    "3. The propeller assembly of claim 2 wherein said means extending through said first and second openings comprises; a pin.",
    "4. The propeller assembly of claim 3 wherein said pin further comprises; a hollow pin.",
    "5. The propeller assembly of claim 4 wherein said hollow pin further comprises; a threaded interior portion for cooperating with a screw, said screw engaging said threaded interior portion so that said pin may be removed from said recess and said opening.",
    "6. A propeller assembly having a hub and a spinner for covering said hub forming a smooth aerodynamic surface, said propeller assembly comprising: a pitch member attaching to said hub for rotation therein, a swept, essentially composite, propeller or fan blade, and, a means for mounting said swept propeller or fan blade to said pitch member radially outwardly from said spinner such that said fan blade may be readily removed from said pitch member and for modifying a response of said blade to the vibratory excitation in the first mode of vibration such that a twisting motion of the blade is minimized."
  ],
  "description_excerpt": "This invention relates to an assembly for mounting a propeller blade to a hub.\n\nAircraft propeller blades are subject to damage from foreign objects such as sand, rain, hail, and birds etc. Propeller blades that are mounted towards the rear of an aircraft are particularly susceptible to foreign object damage. Runway debris, such as sand, runway markers, stones, ice, water, slush and segments of tire tread etc., may be kicked up into a plane of rotation of the blades. Collision between the foreign objects and the propeller blades may require the removal of the damaged blades from the propeller for repair.\n\nTypically, propeller blades are mounted to a hub of a propeller by means of a blade retention member. The member is rotatable within the hub to allow the pitch of the propeller blade mounted therein to be set as required. A spinner may enclose the hub and the member.\n\nTo replace a damaged blade, the spinner and/or the blade retention member and/or the hub may have to be disassembled. Because of the complexity of the disassembly (and subsequent reassembly), blade changes are time consuming, expensive and subject to error. The problem is multiplied by propellers which have a plurality of blades.\n\nIn counter-rotation prop-fans, each blade is rather heavily loaded absorbing as much as 1000 horsepower of engine torque and developing as much as 1,500 pounds of engine thrust. Heavily loaded propeller blades are subject to high vibratory loads and stresses. Moreover because prop-fan blades are swept, they are subject to instability at high speed.",
  "cpc": [
    "B64C 11/04",
    "Y02T 50/60"
  ],
  "ipc": [
    "B64C 11/04",
    "B64C 11/06"
  ],
  "assignees": [
    "United Technologies Corp"
  ],
  "inventors": [
    "John A. Violette",
    "Sean Auyeung",
    "David P. Nagle"
  ],
  "filing_date": "1988-10-07",
  "publication_date": "1992-04-07",
  "grant_date": "1992-04-07",
  "priority_date": "1988-10-07",
  "application_number": "US-25581588-A",
  "family_id": "22969986",
  "cited_by_count": 27,
  "citations": [
    "US961328A",
    "GB113324A",
    "GB267179A",
    "US1802648A",
    "US1863387A",
    "US2317338A",
    "US2658718A",
    "US2536041A",
    "GB621315A",
    "US2665054A",
    "US2656146A",
    "US2559131A",
    "US2651494A",
    "US2980395A",
    "US2873088A",
    "US3047726A",
    "US3039739A",
    "US2990018A",
    "GB980656A",
    "US3310120A",
    "US3487879A",
    "US3572970A",
    "US3554668A",
    "US3860361A",
    "US4047840A",
    "US4045149A",
    "US4019832A",
    "US4037990A",
    "US4212588A",
    "SU1114820A1",
    "US4626169A",
    "US4767271A",
    "US4738591A"
  ]
}