Torque limiter devices, systems and methods and solar trackers incorporating torque limiters

{
  "publication_number": "US10809345B2",
  "country": "US",
  "kind": "B2",
  "title": "Torque limiter devices, systems and methods and solar trackers incorporating torque limiters",
  "abstract": "A solar tracker assembly comprises a support column, a torsion beam connected to the support column, a mounting mechanism attached to the torsion beam, a drive system connected to the torsion beam, and a torsion limiter connected to an output of the drive system. When an external force causes a level of torsion on the drive system to exceed a pre-set limit the torsion limiter facilitates rotational movement of the solar tracker assembly in the direction of the torsion, thereby allowing the external force to rotate about a pivot axis extending through the torsion beam. Exemplary embodiments also include methods of aligning a plurality of rows of solar trackers.",
  "claims": [
    "1. A solar tracker assembly comprising: one or more support columns; one or more torque tubes or torsion beams connected to the support columns, the one or more torque tubes or torsion beams rotatable relative to the support columns; a mounting mechanism attached to the one or more torque tubes or torsion beams, the mounting mechanism configured to connect one or more solar modules to the one or more torque tubes or torsion beams; a drive system configured to rotate the one or more torque tubes or torsion beams; a torque limiter connected to the drive system; and a plurality of mechanical stops disposed at a maximum rotational position of the solar tracker assembly; wherein when a hinge moment force causes a level of torque on the drive system to exceed a pre-set limit, the torque limiter facilitates rotational movement of the solar tracker assembly in the direction of the torque, thereby allowing the hinge moment force to rotate the mounting mechanism about a pivot axis extending through the one or more torque tubes or torsion beams; and wherein, when the torque limiter facilitates rotational movement of the solar tracker, the plurality of mechanical stops prevents rotational movement of the solar tracker assembly beyond the maximum rotational position at multiple locations.",
    "2. The solar tracker assembly of claim 1, wherein the movement in the direction of the torque de-couples excess torque such that the external force is released and the level of torsion on the solar tracker assembly is reduced.",
    "3. The solar tracker assembly of claim 2, wherein the movement in the direction of the torque comprises movement of the solar tracker assembly from a first rotational position to at least one second rotational position.",
    "4. The solar tracker assembly of claim 3, wherein the solar tracker assembly is disposed at the maximum rotational position in the at least one second rotational position.",
    "5. The solar tracker assembly of claim 3, wherein the solar tracker assembly is constrained in its maximum rotational positions at multiple distributed locations along a torsional resisting structure of the solar tracker assembly.",
    "6. The solar tracker assembly of claim 5, wherein the solar tracker assembly includes a plurality of support columns and further comprises a stop of the plurality of mechanical stops at each support column.",
    "7. The solar tracker assembly of claim 1, wherein the torsion limiter limits a hinge moment about the pivot axis extending through a torque tube or torsion beam of the one or more torque tubes or torsion beams.",
    "8. The solar tracker assembly of claim 1, wherein the drive system comprises a gear assembly including at least one gear wheel.",
    "9. The solar tracker assembly of claim 8, wherein the gear assembly includes a one-way gearbox and the torque limiter is a torque limiting clutch contained within the gearbox.",
    "10. The solar tracker assembly of claim 8, wherein the gear assembly includes a friction coupling engaging the gear wheel and the torque limiter is located at the friction coupling.",
    "11. The solar tracker assembly of claim 8, wherein the torque limiter is located at the output of a first gear stage of the gear assembly.",
    "12. The solar tracker assembly of claim 1, wherein the solar tracker assembly is a push/pull linked tracker and the torque limiter is a linear slip device.",
    "13. The solar tracker assembly of claim 1, wherein the solar tracker assembly includes a hydraulic system and the torque limiter is a pressure relief valve.",
    "14. The solar tracker assembly of claim 1, further comprising a damper to control release of torque force and slow motion of the solar tracker assembly.",
    "15. The solar tracker assembly of claim 1, wherein the torque limiter acts as an overload relief from input force of the drive system when an external obstruction causes resistance on the solar tracker.",
    "16. The solar tracker assembly of claim 1, wherein the one or more torque tubes or torsion beams are configured with a balanced center of gravity such that a weight of the mounting mechanism and any components mounted thereto is rotated about a balance point such that torsional release force remains constant at all rotational positions of the solar tracker.",
    "17. An array of solar trackers comprising: a plurality of solar modules; a plurality of support columns; a plurality of torque tubes, the torque tubes being supported by the support columns, the torque tubes, the support columns, and the solar modules being configured to form a plurality of rows of solar trackers, each row of the plurality of rows of solar trackers including a torque tube; a drive system configured to simultaneously rotate each torque tube from the plurality torque tubes; and a plurality of torsion limiters, a torsion limiter disposed between the drive system and each torque tube of the plurality of torque tubes, the plurality of torsion limiters allowing at least one row of the plurality of rows of solar trackers to not rotate while allowing rotation of other rows of solar trackers.",
    "18. The solar tracker assembly of claim 17, wherein an external force causes a level of torsion to exceed a preset limit the torsion limiter facilitates rotational movement of the solar tracker assembly.",
    "19. The solar tracker assembly of claim 17, wherein the torsion limiter facilitates rotational movement of the solar tracker assembly to a different position until either a level of torsion no longer exceeds a preset limit, or the solar tracker is restrained from further rotation at multiple points by multiple stops.",
    "20. The solar tracker assembly of claim 17, further comprising one or more stops connected to each support column of the plurality of support columns, the stops preventing rotation of the solar tracker beyond a maximum rotational position.",
    "21. The solar tracker assembly of claim 17, further comprising a plurality of stops, the plurality of stops preventing rotation of the solar tracker beyond a maximum rotational position at multiple locations.",
    "22. The solar tracker assembly of claim 17, wherein the torque limiter is a torque limiting clutch, a slip clutch, a friction coupling, a linear slip device, a linear clutch linkage, a pressure relief valve, a motor brake, a clutch assembly, or a bi-directional gear drive."
  ],
  "description_excerpt": "The present disclosure relates to torsion limiter devices, systems, and methods. The present disclosure further relates to torque release mechanisms in mechanical positioning systems. The present disclosure further relates to torque limiting and slip clutch assemblies.\n\nAs the wind acts on a solar tracking photovoltaic (PV) array or other mechanically driven positioning systems exposed to outdoor environmental forces, it causes positive and negative pressures on the array which may act independently, cumulatively, or differentially. These wind forces are commonly categorized as drag, uplift, downforce and hinge moment about the rotational axis. The wind forces vary depending upon the wind speed, direction and rotational tracking angle of the array. These forces are also usually greater on the outer structures in a large array field.\n\nTypically, in the case of single axis solar tracking systems, the lift and drag induced on the tracked array or other mechanical system are resisted at multiple points within the structure. However, as evidenced by existing systems, the hinge moment typically is resisted at a single point. The resulting torsional forces applied to relatively long torsion tubes or other beam configurations may be large and tend to interact with the torsional flexibility of the tracker structure. Counteracting the high hinge moment forces at a single point in the structure requires sufficiently strong torsional members to resist both the high combined torque and the beam loads of the system without excess flexibility.",
  "cpc": [
    "G01S 3/7861",
    "F16D 43/2024",
    "F16D 43/215",
    "F24S 2030/115",
    "F24S 2030/134",
    "F24S 2030/136",
    "F24S 2030/15",
    "F24S 30/425",
    "F24S 40/00",
    "H02S 20/30",
    "H02S 30/00",
    "Y02E 10/47",
    "Y02E 10/50"
  ],
  "ipc": [
    "F24S 40/00",
    "F24S 50/20",
    "G01S 3/786",
    "F24S 30/42",
    "F24S 30/425",
    "G01S 3/78"
  ],
  "assignees": [
    "Array Technologies Inc"
  ],
  "inventors": [
    "Ronald P. Corio"
  ],
  "filing_date": "2018-08-06",
  "publication_date": "2020-10-20",
  "grant_date": "2020-10-20",
  "priority_date": "2014-02-19",
  "application_number": "US-201816055663-A",
  "family_id": "53797948",
  "cited_by_count": 19,
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