Roller gear for a drive system

{
  "publication_number": "US2017096217A1",
  "country": "US",
  "kind": "A1",
  "title": "Roller gear for a drive system",
  "abstract": "A roller gear for use in a roller gear and sprocket configuration of a drive system is disclosed, particularly for use in a landing gear drive system of an aircraft. Alternative embodiments and, in particular, means for permitting removal and replacement of rollers and roller mounting pins in the roller gear are disclosed.",
  "claims": [
    "1. A roller gear comprising: a series of rollers arranged to form a substantially circular array; at least two roller mounting members axially spaced from one another along an axis of rotation of the roller gear, each roller mounting member comprising a substantially circular array of openings for receiving roller mounting pins therein to mount the rollers between the roller mounting members; an array of roller mounting pins disposed in the openings, each of the roller mounting pins comprising a roller mounting shaft, having a longitudinal axis, for entering the roller mounting members and the roller to retain the roller relative to the roller mounting members; at least one of the roller mounting pins comprising a roller mounting pin head, delimited from the shaft by a change in radial dimension of the pin; the roller gear further comprising primary roller mounting pin retaining means, arranged to engage the head of the at least one roller mounting pin to prevent axial movement of the roller mounting pin in a direction of its longitudinal axis. 2. (canceled) 3. A roller gear according to claim 1, wherein the primary roller mounting pin retaining means is arranged to engage or disengage the roller mounting pin by relative rotational movement between the roller mounting pin and the roller mounting pin retaining means. 4. (canceled) 5. (canceled) 6. A roller gear according to claim 1, wherein at least one of the primary and secondary roller pin retaining means is a substantially annular member arranged to retain or lock the array of roller mounting pins simultaneously and/or to release or unlock the array of roller mounting pins simultaneously. 7. A roller gear according to claim 1, further comprising fixing means to fix at least one of the primary and secondary roller pin retaining means relative to a roller mounting member to which it is mounted. 8. (canceled) 9. (canceled) 10. (canceled) 11. (canceled) 12. (canceled) 13. A roller gear according to claim 1, wherein the head of the roller mounting pin has a perimeter having a first, substantially arc-shaped, portion, and a second, substantially straight, portion. 14. (canceled) 15. (canceled) 16. (canceled) 17. (canceled) 18. A roller gear according to claim 1, wherein the primary roller mounting pin retaining means comprises an annular portion arranged around a circumference of the roller mounting member. 19. A roller gear according to claim 18 wherein the primary roller mounting pin retaining means comprises a first, axially extending, annular portion, and a second, radially extending, annular portion. 20. (canceled) 21. A roller gear according to claim 1, wherein the secondary roller mounting pin retaining means is arranged to be detachably mounted adjacent the at least one roller pin head. 22. A roller gear according to claim 21, wherein the secondary roller mounting pin retaining means is arranged at a distance, from a centre of the opening in which the at least one roller pin is located, which is less than the maximum radial dimension of the roller pin head. 23. (canceled) 24. A roller gear according to claim 1, wherein the secondary roller mounting pin retaining means is arranged to retain more than one roller mounting pin of the roller gear. 25. A roller gear according to claim 1, wherein the secondary roller mounting pin retaining means is a substantially annular ring, arranged such that at least one of its inner or outer edges is located at a distance, from a centre of the openings in which the roller pins are located, which is less than a maximum radial dimension of the roller pin heads. 26. A roller gear according to claim 20, wherein the secondary roller mounting pin retaining means is repeatably attachable and detachable from the roller mounting member to lock and release the roller mounting pins. 27. (canceled) 28. A roller gear according to claim 1, wherein at least one roller mounting pin has a neck of reduced diameter relative to the pin head and the pin shaft, for engaging the primary pin head retaining means to retain the pin in the roller gear. 29. A roller gear according to claim 28, wherein the primary roller mounting pin retaining means has a pin head retaining portion having a pair of opposed sides spaced apart by a distance greater than the diameter of the neck of the roller mounting pin and less than the diameter of the head and the diameter of the shaft of the roller mounting pin. 30. A roller gear according to claim 28, wherein the primary roller mounting pin retaining means further comprises a pin head release portion having opposing faces spaced apart by a distance greater than the diameter of the pin head or the shaft of the roller mounting pin. 31. A roller gear according to claim 30, wherein the primary pin head retaining means has an opening comprising a pin head retaining portion having a pair of opposed sides spaced apart by a distance greater than the diameter of the neck of the roller mounting pin and less than the diameter of the head and the diameter of the shaft of the roller mounting pin, and a pin head release portion having opposing faces spaced apart by a distance greater than the diameter of the pin head or the shaft of the roller mounting pin. 32. A roller gear according to claim 31, wherein the primary roller mounting pin retaining means is slidable relative to the roller mounting member to selectively locate the roller mounting pin head in the pin head retaining portion or the pin head release portion. 33. A roller gear according to claim 30, wherein the primary roller mounting pin retaining means is a substantially annular ring comprising an array of openings comprising a pin head retaining portion having a pair of opposed sides spaced apart by a distance greater than the diameter of the neck of the roller mounting pin and less than the diameter of the head and the diameter of the shaft of the roller mounting pin, and a pin head release portion having opposing faces spaced apart by a distance greater than the diameter of the pin head or the shaft of the roller mounting pin. 34. A roller gear according to claim 33, wherein the primary roller mounting pin retaining means is arranged to be rotatable from a first position, in which the array of openings in the roller mounting members is aligned with the array of pin head retaining portions, and a second position, in which the array of openings in the roller mounting members is aligned with the array of pin head release portions. 35. A body for a roller gear comprising: first and second roller mounting members, each roller mounting member comprising a plurality of openings arranged in a substantially circular array, for receiving roller mounting pins to mount rollers thereto; at least one of the roller mounting members comprising roller mounting pin retaining means, arranged to engage a head of at least one of the roller mounting pins to retain the head between the roller mounting member and the roller pin head retaining means. 36. A roller mounting pin for a roller gear according to claim 1, comprising: a pin mounting shaft, having a first diameter, for entering the roller mounting members and the roller, to rotatably mount the roller relative to the roller mounting members; and a head, having a first portion having a first radial dimension greater than the diameter of the pin mounting shaft, to prevent movement of the head relative to the roller mounting members in a first axial direction; and wherein the head of the pin has a second portion having a second radial dimension, smaller than the first radial dimension. 37. (canceled) 38. (canceled) 39. (canceled) 40. (canceled) 41. An aircraft undercarriage drive system comprising a roller gear according to claim 1. 42. An aircraft undercarriage drive system according to claim 41, wherein the drive system is supported by a bracket which is rigidly connected to the axle, main fitting or slider part of the landing gear. 43. An aircraft undercarriage drive system according to claim 42, wherein the bracket includes two lugs comprising half-moon clamps to permit ready attachment and detachment of the bracket."
  ],
  "description_excerpt": "The present invention relates to a gear for a drive system for rotating one or more wheels of an aircraft landing gear for the purposes of ground taxiing (forwards or reverse) and/or wheel spin-up prior to landing and/or for applying braking torque to the rotating wheel(s).\n\nAircraft are required to ground taxi between locations on airfields. An example is taxiing between a runway and the location (e.g. terminal gate) at which the aircraft's passengers are to board or disembark. Typically, such taxiing is achieved by using the thrust from the aircraft's engines to propel the aircraft forwards so that the landing gear wheels are caused to rotate. Since ground taxi speeds are necessarily relatively low, the engines must be run at a very low power. This means that there is a relatively high fuel consumption as a result of the poor propulsion efficiency at this low power. This leads to an increased level of both atmospheric and noise pollution locally around airports. Moreover, even when the engines are run at low power it is generally necessary to apply the wheel brakes to limit around taxi speeds, leading to a high degree of brake wear.\n\nReversing of a civil aircraft, e.g. away from a terminal gate, using its main engines is not permitted. When reversing is necessary, or in other situations where ground taxiing via main engine thrust is not practicable, tow trucks are used to manoeuvre aircraft around. This process is laborious and costly.\n\nThere is therefore a need for a drive system to power the wheels of an aircraft landing gear during ground taxi operations.",
  "cpc": [
    "B64C 25/405",
    "B64C 25/34",
    "B64C 25/40",
    "F16B 21/02",
    "F16B 21/04",
    "F16B 5/10",
    "F16C 13/00",
    "F16H 1/00",
    "F16H 55/00",
    "F16H 55/10",
    "F16H 55/17",
    "F16H 57/0427",
    "F16H 57/0464",
    "F16H 57/0471",
    "Y02T 50/80"
  ],
  "ipc": [
    "B64C 25/40",
    "F16B 21/04",
    "F16B 5/10",
    "F16H 55/10"
  ],
  "assignees": [
    "Airbus Operations Ltd"
  ],
  "inventors": [
    "Arnaud Didey",
    "Richard BILLYEALD",
    "James SETTER",
    "Ian DICKASON"
  ],
  "filing_date": "2015-03-16",
  "publication_date": "2017-04-06",
  "priority_date": "2014-03-17",
  "application_number": "US-201515126957-A",
  "family_id": "50634893",
  "cited_by_count": 6,
  "citations": [
    "US1200203A",
    "US20110023505A1",
    "US20130000826A1"
  ]
}