Railroad Sweeper Assembly

Abstract

A rail sweeper assembly includes a vehicle, a debris removal system, and a first conveyor system. The vehicle is configured to travel on a railroad track. The railroad track includes a pair of railroad rails. The debris removal system is rotatably coupled to the vehicle at a first location and configured to lift debris from the railroad track. The first conveyor system is rotatably coupled to the vehicle at a second location and configured to receive the debris from the debris removal system.

Claims

1. A rail sweeper assembly comprising: a vehicle configured to travel on a railroad track; a debris removal system rotatably coupled to the vehicle at a first location and configured to lift debris from the railroad track; and a first conveyor system rotatably coupled to the vehicle at a second location and configured to receive the debris from the debris removal system.

2. The rail sweeper assembly of claim 1, wherein the debris removal system includes: a debris elevator rotatably coupled to the vehicle at the first location; and a sweeper head rotatably coupled to the debris elevator at a third location.

3. The rail sweeper assembly of claim 2, wherein the debris elevator includes a plurality of paddles configured to move debris from the railroad track to the first conveyor system.

4. The rail sweeper assembly of claim 2, wherein the sweeper head includes a plurality of bristles arranged concentrically around a central axis of the sweeper head and configured to lift debris from the railroad track.

5. The rail sweeper assembly of claim 2, wherein the railroad track includes a pair of rails, and wherein the sweeper head is configured to operate between the pair of rails.

6. The rail sweeper assembly of claim 2, wherein the first conveyor system includes: a first hopper configured to receive debris from the debris elevator; and a first conveyor belt configured to move the first hopper.

7. The rail sweeper assembly of claim 6, further comprising a second conveyor system coupled to the vehicle at a fourth location and configured to receive the debris from the first conveyor system.

8. The rail sweeper assembly of claim 7, wherein the second conveyor system includes: a second hopper configured to receive debris from the first hopper; and a second conveyor belt configured to move the first hopper.

9. The rail sweeper assembly of claim 8, wherein the second conveyor system is configured to rotate three hundred sixty degrees.

10. The rail sweeper assembly of claim 8, further comprising a train car coupled to the vehicle, and wherein the second conveyor system deposits debris in the train car.

11. The rail sweeper assembly of claim 1, further comprising a vacuum system coupled to the vehicle and configured to remove debris inside of a transition area of the railroad track.

12. The rail sweeper assembly of claim 11, wherein the vacuum system includes an air compressor and an air spade coupled to the air compressor.

13. The rail sweeper assembly of claim 12, wherein the vacuum system is configured to force a fluid out of the air spade using the air compressor, and the fluid loosens or removes the debris inside the transition area.

14. The rail sweeper assembly of claim 13, wherein the vacuum system is configured to collect the debris inside the transition area.

15. The rail sweeper assembly of claim 1, further comprising at least one side sweeper configured to remove debris from at least one of: a railroad rail of the railroad track; a railroad tie of the railroad track; or a walking area of the railroad track.

16. The rail sweeper assembly of claim 15, wherein the railroad track includes a pair of rails, and wherein the at least one side sweeper is configured to move the debris into an area in between the pair of rails.

17. The rail sweeper assembly of claim 15, wherein the at least one side sweeper includes a first side sweeper disposed on a first side of the vehicle and a second side sweeper disposed on a second side of the vehicle.

18. The rail sweeper assembly of claim 1, further comprising a strut coupled to the vehicle and the first conveyor system.

19. The rail sweeper assembly of claim 1, wherein the vehicle includes a set of front hi-rail wheels and a set of rear hi-rail wheels.

20. The rail sweeper assembly of claim 1, wherein the rail sweeper assembly is configured to move between an operating position and transport position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present disclosure will become more fully understood from the detailed description and the accompanying drawings.

[0011] FIG. 1 is a schematic view of an example rail sweeper assembly in a first configuration according to the principles of the present disclosure.

[0012] FIG. 2 is a schematic view of the rail sweeper assembly of FIG. 1 in a second configuration according to the principles of the present disclosure.

[0013] FIG. 3 is a schematic view of the rail sweeper assembly of FIG. 1 in a third configuration according to the principles of the present disclosure.

[0014] FIG. 4 is a schematic view of a second example rail sweeper assembly in a first configuration according to the principles of the present disclosure.

[0015] FIG. 5 is a schematic view of the rail sweeper assembly of FIG. 4 in a second configuration according to the principles of the present disclosure.

[0016] FIG. 6 is a plan view of an example railroad track according to the principles of the present disclosure.

[0017] In the drawings, reference numbers may be reused to identify similar and/or identical elements.

DETAILED DESCRIPTION

[0018] Referring to FIGS. 1-3, a rail sweeper assembly 10 is illustrated. As will be explained in more detail below, the rail sweeper assembly 10 may clean (e.g., remove debris from) a railroad track 12. When the rail sweeper assembly 10 is cleaning the railroad track 12, it may be in a first (e.g., operating) position (FIG. 1), and when the rail sweeper assembly 10 is not cleaning the railroad track 12, it may be in a second (e.g., transport) position (FIG. 2).

[0019] As illustrated in FIG. 6, the railroad track 12 may include a pair of railroad rails 14 and a plurality of railroad ties 16 supporting the pair of railroad rails 14. In some implementations, the railroad track 12 includes a transition area 18. In some implementations, the railroad track 12 includes a walking area 19.

[0020] The rail sweeper assembly 10 may include a vehicle 20, a debris removal system 22, and a first conveyor system 24. The debris removal system 22 may be coupled (e.g., rotatably coupled) to the vehicle 20 at a first location 26. For example, an arm 27 may connect the debris removal system 22 to the vehicle 20. The debris removal system 22 may rotate around a first axis of rotation A1 at the first location 26. The debris removal system 22 may remove (e.g., lift or sweep) debris (not shown) from the railroad track 12. The first conveyor system 24 may be coupled (e.g., rotatably coupled) to the vehicle 20 at a second location 28 and may receive debris from the debris removal system 22. The first conveyor system 24 may rotate around a second axis of rotation A2 at the second location 28.

[0021] The vehicle 20 may be configured to travel on the railroad track 12. The vehicle 20 may include one or more sets of hi-rail wheels 21 (e.g., front and rear sets). The hi-rail wheels 21 may be configured to engage and roll along the railroad rails 14 to keep the rail sweeper assembly 10 on the railroad track 12.

[0022] The debris removal system 22 may include a debris elevator 30 and a sweeper head 32. The debris elevator 30 may be coupled (e.g., rotatably coupled) to the vehicle 20 at the first location 26 (e.g., by the arm 27). The debris elevator 30 may rotate around the first axis of rotation A1 at the first location 26. The sweeper head 32 may be coupled (e.g., rotatably coupled) to the debris elevator 30 at a third location 34. The sweeper head 32 may rotate around a third axis of rotation A3 at the third location 34. The sweeper head 32 and debris elevator 30 may work in parallel to lift and remove debris from the railroad track 12.

[0023] The debris elevator 30 may include a plurality of paddles 36 connected to each other by a track 38. The track 38 may move the paddles 36 around (e.g., counterclockwise) the debris elevator 30. The paddles 36 may be configured to pick up debris from the railroad track 12 at a first end 40 of the debris elevator 30 and deposit the debris in the first conveyor system 24 when the paddle 36 reaches a second end 42 of the debris elevator 30. In some implementations, the paddles 36 are scoops or buckets. In some implementations, the debris elevator 30 runs continuously while the rail sweeper assembly 10 is in operation.

[0024] The sweeper head 32 may include a plurality of bristles 44 configured to remove debris from the railroad track 12. The sweeper head 32 may be configured to operate between the pair of railroad rails 14. For example, the sweeper head 32 may be sized to fit in between the pair of railroad rails 14. The plurality of bristles 44 may be arranged (e.g., concentrically) around a central axis A6 of the sweeper head 32. In some implementations, the sweeper head 32 may be substantially in the shape of a drum or roller.

[0025] The first conveyor system 24 may include a first hopper 48 and first conveyor belt 50. The first hopper 48 may be configured to hold debris received from the debris elevator 30. In some implementations, the first hopper 48 is a bucket or basket. The first conveyor belt 50 may be configured to move the first hopper 48 from a first position 52, where the first hopper 48 may receive the debris from the debris elevator 30, to a second position 54, where the first hopper 48 may transfer the debris (e.g., to the second conveyor system 58). As illustrated, the first position 52 may be located at a proximal end of the first conveyor system 24, and the second position 54 may be located at a distal end (opposite the proximal end) of the first convey system 24. In some implementations, the first hopper 48 remains in the first position 52 until the debris removal system 22 finishes removing debris. In some implementations, the first hopper 48 never fills completely with debris. In some implementations, a strut 56 couples the first conveyor system 24 to the vehicle 20.

[0026] In some implementations, the rail sweeper assembly 10 includes a second conveyor system 58. The second conveyor system 58 may be coupled (e.g., rotatably coupled) to the vehicle 20 at a fourth location 60. The second conveyor system 58 may rotate around a fourth axis of rotation A4 at the fourth location 60. The fourth axis of rotation A4 may extend in a direction substantially (e.g., +/10 degrees) orthogonal to the first, second, and/or third axes of rotations A1-A3. The second conveyor system 58 may include a second hopper 62 and a second conveyor belt 64. The second hopper 62 may be configured to hold debris received from the first conveyor system 24 (e.g., the first hopper 48). In some implementations, the second hopper 62 is a bucket or basket. The second conveyor belt 64 may be configured to move the second hopper 62 from a third position 66, where the second hopper 62 may receive debris from the first conveyor system 24 (e.g., the first hopper 48), to a fourth position 68, where the second hopper 62 may transfer the debris. In some implementations, at the fourth position 68, the second hopper 62 transfers the debris to a train car or dump truck 69 coupled to the vehicle 20. In some implementations, at the fourth position 68, the second hopper 62 transfers the debris to a position 70 outside of the railroad track 12. In some implementations, the second conveyor system 58 is capable of rotating three hundred sixty degrees (360) around the fourth axis of rotation A4.

[0027] In some implementations, the debris removal system 22, the first conveyor system 24, and the second conveyor system 58 are hydraulically-driven.

[0028] In some implementations, the rail sweeper assembly 10 includes a vacuum system 72 coupled to the vehicle 20. The vacuum system 72 may include an air compressor 74 coupled to an air spade 76. The vacuum system 72 may be configured to remove debris from the transition area 18 of the railroad track 12. For example, the vacuum system 72 may force a fluid (e.g., air) out of the air spade 76 using the air compressor 74. The forced air may loosen or remove (e.g., blow away) debris in the transition area 18. In some implementations, the vacuum system 72 then collects (e.g., suck up) the loosened debris out of the transition area 18.

[0029] In some implementations, the rail sweeper assembly 10 includes one or more side sweepers 78 coupled to a bottom side 80 of the vehicle 20. In some implementations, the rail sweeper assembly 10 includes two side sweepers 78 that are thirty-six inches (36) in diameter. The side sweepers 78 may be configured to remove debris from the railroad rails 14, railroad ties 16, or the walking area 19 of the railroad track 12. The debris removed by the side sweepers 78 may be pushed inside the pair of railroad rails 14 to be picked up by the sweeper head 32 or the debris may be pushed off of the railroad track 12.

[0030] Referring now to FIGS. 4 and 5, a rail sweeper assembly 10a is shown. In view of the substantial similarity in structure and function of the components associated with the rail sweeper assembly 10a with respect to the rail sweeper assembly 10, like reference numerals are used hereinafter, and in the drawings, to identify like components while like reference numerals containing letter extensions (e.g., a) are used to identify those components that have been modified. Any references herein to the rail sweeper assembly 10, or any component thereof, will be understood to apply equally to the rail sweeper assembly 10a, or the corresponding component thereof, unless otherwise noted.

[0031] The rail sweeper assembly 10a may include the vehicle 20, a debris removal system 22a, and the first conveyor system 24. In some implementations, the rail sweeper assembly 10a includes a second conveyor system 58a. In some implementations, the rail sweeper assembly 10a includes at least one of the vacuum system 72 or the one or more side sweepers 78.

[0032] The debris removal system 22a may include the debris elevator 30 and the sweeper head 32. The debris removal system 22a may be coupled (e.g., rotatably coupled) to the vehicle 20 at the first location 26 and at a fifth location 82. For example, a first arm 27-1 may connect the debris removal system 22a to the vehicle 20 at the first location 26 and a second arm 27-2 may connect the debris removal system 22a to the vehicle 20 at the fifth location 82. The debris removal system 22a may rotate around the first axis of rotation A1 at the first location 26. The debris removal system 22a may also rotate around a fifth axis of rotation A5 at the fifth location 82. The debris elevator 30 may be coupled (e.g., rotatably coupled) to the vehicle 20 at the first location 26 (e.g., by the first arm 27-1) and at the fifth location 82 (e.g., by the second arm 27-2).

[0033] The second conveyor system 58a may include the second hopper 62 and the second conveyor belt 64. The second conveyor system 58a may be coupled (e.g., rotatably-, translatably-, and/or pivotably-coupled) to the vehicle 20. For example, the second conveyor system 58a may move between a first (e.g., working) position (FIG. 4) and a second (e.g., traveling) position (FIG. 5). When the second conveyor system 58a is in the second position (FIG. 5), the second conveyor system 58a may be located at the fourth location 60. When the second conveyor system 58a is in the first position (FIG. 4), the second conveyor system 58a may be located at a sixth location 84. The second conveyor system 58a may move (e.g., translate) from the second position (FIG. 5) to the first position (FIG. 4) by translating (e.g., sliding) along one or more rails 86. In particular, the second conveyor system 58a may translate along the rails 86 in a direction substantially parallel to the axes A1, A2, and/or A3, and substantially orthogonal to the axis A4.

[0034] The second conveyor system 58a may pivot and rotate around the fourth axis of rotation A4 at the fourth location 60. In this regard, the second conveyor system 58a may move (e.g., pivot and/or rotate) the second conveyor belt 64 from a position beneath the first conveyor system 24 (FIG. 5) to a position above the vehicle 20 (FIG. 4). In some implementations, the second conveyor system 58a is capable of rotating three hundred sixty degrees) (360 around the fourth axis of rotation A4. The second conveyor system 58a may be hydraulically-driven.

[0035] A method of operating a rail sweeper assembly (e.g., rail sweeper assembly 10, 10a) will now be described with reference to FIGS. 1-6. The method may begin with the rail sweeper assembly 10, 10a disposed off of the railroad track 12. When the rail sweeper assembly 10, 10a is off of the railroad track 12, it may be in the second (e.g., transport) position (FIG. 2). The vehicle 20 of the rail sweeper assembly 10, 10a then drives onto the railroad track 12. The rail sweeper assembly 10, 10a then deploys the one or more sets of hi-rail wheels 21, which engage the pair of railroad rails 14.

[0036] The rail sweeper assembly 10, 10a then moves to the first (e.g., operating) position (FIG. 1) by first rotating the second conveyor system 58, 58a around the fourth axis of rotation A4. In implementations with the second conveyor system 58a, the second conveyor system 58a moves along the one or more rails 86 from the sixth location 84 to the fourth location 60 before rotating around the fourth axis of rotation A4. Next, the debris removal system 22, 22a rotates around the first axis of rotation A1 until the debris elevator 30 contacts the railroad track 12. In some implementations, the debris removal system 22a also rotates around the fifth axis of rotation A5 until the debris elevator 30 contacts the railroad track 12. Next, the sweeper head 32 rotates around the third axis of rotation A3 until the sweeper head 32 contacts the railroad track 12. Finally, the first conveyor system 24 rotates (e.g., by a force applied by the strut 56) around the second axis of rotation A2 until the second position 54 of the first conveyor system 24 is located above the second conveyor system 58.

[0037] Once the rail sweeper assembly 10, 10a is in the first (e.g., operating) position (FIG. 1), the rail sweeper assembly 10, 10a begins to remove debris from the railroad track 12. The sweeper head 32 loosens debris (e.g., by the plurality of bristles 44) on the railroad track 12 by spinning around the central axis A6. The plurality of paddles 36 of the debris elevator 30 capture the debris at the first end 40 of the debris elevator 30 and deposits the debris in the first hopper 48, when the paddle 36 reaches the second end 42 of the debris elevator 30. Once the sweeper head 32 and debris elevator 30 are done operating, the first hopper 48 will hold the debris picked up from the railroad track 12.

[0038] The first conveyor belt 50 may drive the first hopper 48 from the first position 52 to the second position 54. When the first hopper 48 reaches the second position 54, the first hopper 48 transfers (e.g., dumps) the debris into the second hopper 62. The second conveyor belt 64 then drives the second hopper 62 from the third position 66 to the fourth position 68. The second hopper 62 then dumps the debris (e.g., into a train car or dump truck 69 or a position outside of the railroad track 12). Throughout operation of the rail sweeper assembly 10, 10, the side sweepers 78 may continuously operate to remove debris from the railroad rails 14, railroad ties 16, or the walking area 19 of the railroad track 12.

[0039] In some instances, the rail sweeper assembly 10, 10a reaches a transition area 18 of the railroad track 12. The rail sweeper assembly 10, 10a may stop using the debris removal system 22 at the transition area 18. The rail sweeper assembly 10, 10a instead uses the vacuum system 72 to remove debris from the transition area 18. The vacuum system 72 forces a fluid (e.g., air) out of the air spade 76 using the air compressor 74 to loosen or remove (e.g., blow away) debris in the transition area 18. The vacuum system 72 then collects (e.g., sucks up) the loosened debris out of the transition area 18. After the rail sweeper assembly 10, 10a passes the transition area 18, it continues using the debris removal system 22.

[0040] When the rail sweeper assembly 10, 10a completes cleaning of the railroad track 12, it exits the railroad track 12 and moves back into the second (e.g., transport) position (FIG. 2).

[0041] Referring now to FIG. 3, at various times, the rail sweeper assembly 10, 10a may operate in a third (e.g., reloading) position. The third position may be substantially similar to the second (e.g., transport) position (FIG. 2), except that in the third position the debris removal system 22 may rotate (e.g., counterclockwise) about the third axis of rotation A3 (e.g., at the third location 34), such that the sweeper head 32 is disposed above the first hopper 48. With the sweeper head 32 disposed above the first hopper 48, the first hopper 48 may receive debris from a loader 88 (e.g., a front-end loader, backhoe, bobcat, etc.). The loader 88 may collect debris from the railroad track 12 (e.g., before or after the railroad track is cleaned by the rail sweeper assembly 10, 10a).

[0042] The following Clauses provide an exemplary configuration for a rail sweeper assembly, as described above.

[0043] Clause 1: A rail sweeper assembly comprising: a vehicle configured to travel on a railroad track having a pair of railroad rails; a debris removal system rotatably coupled to the vehicle at a first location and configured to lift debris from the railroad track; and a first conveyor system rotatably coupled to the vehicle at a second location and configured to receive the debris from the debris removal system.

[0044] Clause 2: The rail sweeper assembly of clause 1, wherein the debris removal system includes: a debris elevator rotatably coupled to the vehicle at the first location; and a sweeper head rotatably coupled to the debris elevator at a third location.

[0045] Clause 3: The rail sweeper assembly of clause 2, wherein the debris elevator includes a plurality of paddles configured to move debris from the railroad track to the first conveyor system.

[0046] Clause 4: The rail sweeper assembly of clauses 2 or 3, wherein the sweeper head includes a plurality of bristles arranged concentrically around a central axis of the sweeper head and configured to lift debris from the railroad track.

[0047] Clause 5: The rail sweeper assembly of any of clauses 2 through 4, wherein the sweeper head operates between the pair of railroad rails.

[0048] Clause 6: The rail sweeper assembly of any of clauses 2 through 5, wherein the first conveyor system includes: a first hopper configured to receive debris from the debris elevator; and a first conveyor belt configured to move the first hopper.

[0049] Clause 7: The rail sweeper assembly of clause 6, further comprising a second conveyor system coupled to the vehicle at a fourth location and configured to receive the debris from the first conveyor system.

[0050] Clause 8: The rail sweeper assembly of clause 7, wherein the second conveyor system includes: a second hopper configured to receive debris from the first hopper; and a second conveyor belt configured to move the first hopper.

[0051] Clause 9: The rail sweeper assembly of clauses 7 or 8, wherein the second conveyor system is configured to rotate three hundred sixty degrees.

[0052] Clause 10: The rail sweeper assembly of clauses 8 or 9, further comprising a train car coupled to the vehicle, and wherein the second conveyor system deposits debris in the train car.

[0053] Clause 11: The rail sweeper assembly of any of clauses 1 through 10, further comprising a vacuum system coupled to the vehicle and configured to remove debris inside of a transition area of the railroad track.

[0054] Clause 12: The rail sweeper assembly of clause 11, wherein the vacuum system includes an air compressor and an air spade coupled to the air compressor.

[0055] Clause 13: The rail sweeper assembly of clause 12, wherein the vacuum system is configured to force a fluid out of the air spade using the air compressor, and the fluid loosens or removes the debris inside the transition area.

[0056] Clause 14: The rail sweeper assembly of any of clauses 11 through 13, wherein the vacuum system is configured to collect the debris inside the transition area.

[0057] Clause 15: The rail sweeper assembly of any of clauses 1 through 14, further comprising at least one side sweeper configured to remove debris from at least one of: a railroad rail of the railroad track; a railroad tie of the railroad track; or a walking area of the railroad track.

[0058] Clause 16: The rail sweeper assembly of clause 15, wherein the at least one side sweeper is configured to move the debris into an area in between the pair of railroad rails.

[0059] Clause 17: The rail sweeper assembly of clauses 15 or 16, wherein the at least one side sweeper includes a first side sweeper disposed on a first side of the vehicle and a second side sweeper disposed on a second side of the vehicle.

[0060] Clause 18: The rail sweeper assembly of any of clauses 1 through 17, further comprising a strut coupled to the vehicle and the first conveyor system.

[0061] Clause 19: The rail sweeper assembly of any of clauses 1 through 18, wherein the vehicle includes a set of front hi-rail wheels and a set of rear hi-rail wheels.

[0062] Clause 20: The rail sweeper assembly of any of clauses 1 through 19, wherein the rail sweeper assembly is configured to move between an operating position and transport position.

[0063] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. In the written description and claims, one or more steps within a method may be executed in a different order (or concurrently) without altering the principles of the present disclosure. Similarly, one or more instructions stored in a non-transitory computer-readable medium may be executed in a different order (or concurrently) without altering the principles of the present disclosure. Unless indicated otherwise, numbering or other labeling of instructions or method steps is done for convenient reference, not to indicate a fixed order.

[0064] Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.

[0065] Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including connected, engaged, coupled, adjacent, next to, on top of, above, below, and disposed. Unless explicitly described as being direct, when a relationship between first and second elements is described in the above disclosure, that relationship encompasses a direct relationship where no other intervening elements are present between the first and second elements as well as an indirect relationship where one or more intervening elements are present between the first and second elements.

[0066] As noted below, the term set generally means a grouping of one or more elements. However, in various implementations a set may, in certain circumstances, be the empty set (in other words, the set has zero elements in those circumstances). As an example, a set of search results resulting from a query may, depending on the query, be the empty set. In contexts where it is not otherwise clear, the term non-empty set can be used to explicitly denote exclusion of the empty setthat is, a non-empty set will always have one or more elements.

[0067] A subset of a first set generally includes some of the elements of the first set. In various implementations, a subset of the first set is not necessarily a proper subset: in certain circumstances, the subset may be coextensive with (equal to) the first set (in other words, the subset may include the same elements as the first set). In contexts where it is not otherwise clear, the term proper subset can be used to explicitly denote that a subset of the first set must exclude at least one of the elements of the first set. Further, in various implementations, the term subset does not necessarily exclude the empty set. As an example, consider a set of candidates that was selected based on first criteria and a subset of the set of candidates that was selected based on second criteria; if no elements of the set of candidates met the second criteria, the subset may be the empty set. In contexts where it is not otherwise clear, the term non-empty subset can be used to explicitly denote exclusion of the empty set.

[0068] In the figures, the direction of an arrow, as indicated by the arrowhead, generally demonstrates the flow of information (such as data or instructions) that is of interest to the illustration. For example, when element A and element B exchange a variety of information but information transmitted from element A to element B is relevant to the illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A. Further, for information sent from element A to element B, element B may send requests for, or receipt acknowledgements of, the information to element A.

[0069] The term set generally means a grouping of one or more elements. The elements of a set do not necessarily need to have any characteristics in common or otherwise belong together. The phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean at least one of A, at least one of B, and at least one of C. The phrase at least one of A, B, or C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR.