Rod coupling having a sacrificial element

{
  "publication_number": "US8944189B2",
  "country": "US",
  "kind": "B2",
  "title": "Rod coupling having a sacrificial element",
  "abstract": "The invention relates to a coupling system for rod segments for use in horizontal earth boring, wherein the ends of the rod segments are interlinked via a separate sacrificial element which can be used as a predetermined breaking point or which allows the rod segments to be pivoted relative each other.",
  "claims": [
    "1. A coupling system for boring rod segments, comprising: a plurality of rigid boring rod segments, each of the boring rod segments having a first end including a first wall defining a first recess formed therein, and a second end including a second wall defining a second recess formed therein; a sacrificial element having first and second coupling ends, the first coupling end defining a first journal removably engaged with the first recess of a boring rod segment and the second coupling end defining a second journal removably engaged with the second recess of another boring rod segment for connecting the boring rod segments; wherein the first journal of the first coupling end is shaped such that it is insertable into the first recess when oriented in a first angular position, translatable along a first portion of the first recess in an axial direction of the boring rod segment and into a second portion of the first recess, and constrained from motion in the axial direction of the boring rod segment in the second portion of the first recess when oriented in a second angular position distinct from the first angular position; wherein the second journal of the second coupling end is shaped such that it is insertable into the second recess when oriented in a first angular position, translatable along a first portion of the second recess in an axial direction of the boring rod segment and into a second portion of the first recess, and constrained from motion in the axial direction of the boring rod segment in the second portion of the second recess when oriented in a second angular position distinct from the first angular position.",
    "2. The coupling system according to claim 1, wherein the first coupling end of the sacrificial element is constructed as one of a sphere and a partial sphere.",
    "3. The coupling system according to claim 2, wherein the first coupling end has at least one flat area.",
    "4. The coupling system according to claim 3, wherein the first portion of the first recess includes a flat wall, and wherein the second portion of the first recess comprises a spherical profile complementary to the sphere or partial sphere of the first coupling end.",
    "5. The coupling system according to claim 1, wherein the first coupling end of the sacrificial element is fixated in the second portion of the first recess.",
    "6. The coupling system according to claim 5, wherein the first coupling end is fixated in the second portion of the first recess against pivoting by one of form-fitting, material union, and interference fit.",
    "7. The coupling system according to claim 6, wherein the sacrificial element is fixated with at least one damper arranged in the first recess.",
    "8. The coupling system according to claim 1, wherein each first end of the boring rod segments further comprises a third opening formed therein, the third opening formed generally perpendicular to the first recess for permitting insertion of the first coupling end into the first recess when oriented in the first angular position.",
    "9. The coupling system of claim 1, wherein the first coupling end is constrained to rotation about a first axis oriented generally perpendicular to the axial direction of the rod segment when arranged in the second portion of the first recess.",
    "10. The coupling system of claim 9, wherein the first journal is defined about an axis, and wherein the axis of the first journal is aligned with the first axis oriented generally perpendicular to the axial direction of the rod segment when arranged in the second portion of the first recess.",
    "11. The coupling system of claim 10, wherein the first journal comprises a partially circular profile defined about its axis.",
    "12. The coupling system of claim 1, wherein the second coupling end is constrained to rotation about a second axis oriented generally perpendicular to the axial direction of the rod segment and a third axis oriented generally perpendicular to the second axis and the axial direction of the rod segment when arranged in the second portion of the second recess.",
    "13. The coupling system of claim 1, wherein the first and second walls comprise portions of a continuous wall of a boring rod segment."
  ],
  "description_excerpt": "The invention relates to a rod coupling as it is used for connecting rod assemblies for underground horizontal boring and trench-less installation or replacing of pipelines (horizontal boring hereinbelow). In horizontal boring, individual rod assemblies are strung together, connected with each other and moved through the ground by means of a push, pull, or rotary drive. In the case of longer borings, the rod assembly includes multiple rod segments which are, in accordance with the progress of the boring, connected with or separated from each other, one at a time. The individual rod segment is of limited length and must be very short particularly when the boring takes place in a short building pit, for example a hopper, inspection chamber, or man hole. Such hoppers can have diameters of, in part, less than one meter. Known rod assemblies have couplings of various construction, wherein screw thread couplings are widely used. Aside from the problem that screwing the threaded connections takes a relatively long time and requires clean threads, such connections are particularly disadvantageous in that they allow for rod assembly rotation during the boring progress in one direction only. In the case of, for example, a threaded connection with right-hand thread, rod assembly rotation can only take place in a clockwise direction since otherwise the threaded connection would separate by the boring process.\n\nTherefore, plug-in couplings were developed in the prior art.",
  "cpc": [
    "E21B 17/046",
    "F16B 2200/63",
    "Y10T 29/49718",
    "Y10T 403/7005"
  ],
  "ipc": [
    "E21B 17/02",
    "E21B 17/046"
  ],
  "assignees": [
    "Püttmann Franz-Josef",
    "TRACTO TECHNIK"
  ],
  "inventors": [
    "Püttmann Franz-Josef"
  ],
  "filing_date": "2008-04-04",
  "publication_date": "2015-02-03",
  "grant_date": "2015-02-03",
  "priority_date": "2007-04-05",
  "application_number": "US-59469108-A",
  "family_id": "39831459",
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}