Tool for high voltage transmission lines

{
  "publication_number": "US4670956A",
  "country": "US",
  "kind": "A",
  "title": "Tool for high voltage transmission lines",
  "abstract": "A tool is disclosed that is useful for manipulating the cotter keys that secure the connections between insulators in a high voltage transmission line. In a preferred embodiment, the tool (10) comprises an arm (12) having a first end (14) adapted for connection to a handle (40), and a second end (16) that includes an insert (30) projecting towards the first end. The insert is adapted for insertion into the passage in an insulator so as to engage the split end of a cotter key for partial removal of the cotter key. In a further embodiment, the second end of the tool includes a flange (32) having a concave surface (34, 36) adapted to engage the rounded end of a cotter key and push it back into an insulator.",
  "claims": [
    "1. A tool for manipulating a cotter key held in a socket, the cotter key comprising an elongated member having a rounded end and a split end, the split end comprising a pair of prongs that can be positioned either adjacent to or separated from one another, the socket comprising a body forming an element of an insulator assembly for a high voltage transmission line, the body being shaped so as to form an opening therethrough that includes interconnecting wide and narrow passages, the narrow passage being sized such that the rounded end of the cotter key cannot pass through it, and the split end of the cotter key can pass through it only when the prongs are substantially adjacent to one another, whereby the split end of the cotter key can be inserted through the narrow passage into the wide passage and the cotter key can then be secured in the socket by separating the prongs from one another, the tool comprising an arm having a first end adapted for connection to a handle such that the arm extends from and is parallel to the handle and a second end opposite the first end, the tool further comprising an intermediate member having a first end connected to the second end of the arm and a second end, the intermediate member extending in a direction perpendicular to the arm, and an insert connected to the second end of the intermediate member and projecting towards the first end of the arm in a direction parallel to the arm, the insert having a shape and size that permit the insert to be inserted into the wide passage so as to engage the separated prongs of a cotter key secured therein, the tool further comprising a flange, mounted on the intermediate member, having a concave surface facing away from the first end of the arm, the concave surface being adapted for receiving the rounded end of the cotter key, whereby inserting the insert in the wide passage and pulling the tool towards the first end of the arm will cause the insert to contact the cotter key and to push the cotter key towards the first end of the arm thereby forcing the split ends of the cotter key through the narrow passage and forcing the cotter key partially out of the socket, and whereby the cotter key can be pushed into the opening by engaging the rounded end of the cotter key with the flange and pushing the tool towards the second end of the arm.",
    "2. The tool of claim 1, wherein the split ends of the cotter key have a substantially circular cross section having a predetermined diameter when the prongs are substantially adjacent to one another, and wherein the insert has a rectangular cross section having a height corresponding to the diameter of the cotter key.",
    "3. The tool of claim 1, wherein the socket comprises an insulator that includes a pin adapted to be positioned in the wide passage of a similar first adjacent insulator, a cap including the wide and narrow passages and adapted to receive the pin of a similar second adjacent insulator, and a hemispherical shell having an open end and positioned such that when the pin is positioned in the wide passage of the first adjacent insulator and a second cotter key is secured in the socket of the first adjacent insulator, the second cotter key lies approximately in the plane defined by the open end of the shell, and wherein the second end of the arm is offset with respect to the first end of the arm in a direction transverse to the longitudinal axis of the arm, such that when the tool is approximately parallel to or above said plane, the second end can engage the separated prongs of the second cotter key without interference between the tool and the shell."
  ],
  "description_excerpt": "This application is a continuation application based on prior copending application Ser. No. 628,433, filed July 6, 1984, for Tool for High Voltage Transmission Lines, now abandoned.\n\nIn one type of high voltage transmission system, the high voltage transmission lines are supported from metal towers by insulator assemblies that may be ten or more feet in length. Each insulator assembly comprises a string of insulators fastened together end to end, with each insulator including a pin, a cap, and an intervening hemispherical shell of insulating material such as glass. Pins and caps of adjacent insulators are connected together in a ball and socket fashion, and the connections are secured by cotter keys to produce the complete insulator assembly. During maintenance of high voltage transmission systems, it frequently becomes necessary to remove or replace insulator assemblies while the high voltage line to which the assembly is connected is \"hot.\" Removing or replacing an insulator assembly involves partially removing or inserting one or more of the cotter keys that secure the individual insulators to one another or to the transmission line or tower. Because the line is hot, the cotter keys must be manipulated by a tool held on the end of a long (e.g., 15 foot) insulating handle. One known tool consists of a small hook for engaging the rounded head of a cotter key, so that the cotter key can be hooked and partially removed by pulling on the insulating handle. However, engaging the head of a cotter key with a small hook at the end of a long handle can be a difficult process, particularly in a high wind.",
  "cpc": [
    "H01B 17/04",
    "B25B 27/08",
    "Y10T 29/53809"
  ],
  "ipc": [
    "B25B 27/08",
    "H01B 17/04"
  ],
  "assignees": [
    "MONTANA POWER COMPANY"
  ],
  "inventors": [
    "CHRISTENSEN SHERWOOD D"
  ],
  "filing_date": "1986-03-03",
  "publication_date": "1987-06-09",
  "grant_date": "1987-06-09",
  "priority_date": "1984-07-06",
  "application_number": "US-83542286-A",
  "family_id": "27090704",
  "citations": [
    "US1258016A",
    "US1355174A",
    "US1355631A",
    "US1518068A",
    "US1682009A",
    "US2330013A",
    "US4335477A",
    "US441113A",
    "US895404A"
  ]
}