This document relates to the technical field of (and is not limited to) an apparatus including an aircraft structure having a transmission system, and/or an apparatus including a transmission system for (installation in) an aircraft structure (and method therefor).
An aircraft engine is configured to generate mechanical power for rotating the propeller of an aircraft. An aircraft transmission system (hereinafter referred to as the transmission system) is configured to connect (couple) an aircraft engine to a propeller of an aircraft (also known as an aircraft structure).
It will be appreciated that there exists a need to mitigate (at least in part) at least one problem associated with the existing transmission systems for aircraft structures (also called the existing technology). After much study of the known systems and methods with experimentation, an understanding (at least in part) of the problem and its solution has been identified (at least in part) and is articulated (at least in part) as follows:
Known multirotor (multi-propeller) aircrafts include engines allocated at (positioned at) the periphery (outer edge or envelope) of the aircrafts, in which each engine is utilized for individually powering (driving or rotating) at least one propeller (or a pair of propellers), etc. At least one disadvantage of this arrangement is the additional weight (for the engines) to be carried by the aircrafts, which may (disadvantageously) reduce the effective range or reach of the aircrafts, or may increase fuel costs, etc.
What may be needed (for an aircraft structure) is, preferably, individual control or selective control of the propeller speeds (rotational speeds) of selected propellers via an application of mechanical power from at least one engine assembly (one or more engine assemblies, a single engine assembly, etc.) to the propellers. Of course, what also may be needed is utilizing at least two or more engines for driving (powering respective groupings of propellers, while reducing the total number of engines to be deployed on the aircrafts). In this manner, weight restrictions inherent to known multirotor (multi-propeller) aircrafts may advantageously result in power and/or energy consumption reduction, which may improve (at least in part) the payload loading capability and/or the flight duration capability of the aircraft.
What may be needed (for an aircraft structure) is, preferably, paring and rotating the propellers in opposite directions (relative to each other), and in this manner the paired propellers may nullify an undesired rotational effect resulting from the rotational inertia that is generated by each of the propellers of the aircraft.
What may be needed (for an aircraft structure) is, preferably, a transmission system for an aircraft structure in which the transmission system is configured to vary the amount of mechanical energy to be respectively individually delivered to each of the propellers (or a set of propellers) of the aircraft structure.
What may be needed (for an aircraft structure) is, preferably, a transmission system configured to (A) receive the mechanical energy from an engine assembly, and (B) distribute the mechanical energy (that was received from the engine assembly) to the propellers. This is done in such a way that the transmission system, in use, urges at least two (or more) of the propellers to rotate at rotational speeds (and rotational directions) that are different from each other.
What may be needed (for an aircraft structure) is, preferably, a single engine assembly utilized for providing mechanical power to a transmission system (for the aircraft structure).
To mitigate, at least in part, at least one problem associated with the existing technology, there is provided (in accordance with a major aspect) an apparatus. The apparatus includes and is not limited to an aircraft structure. A first propeller assembly and a second propeller assembly are configured to: (A) be supported by the aircraft structure at a first propeller position and a second propeller position, respectively, and (B) impart, in use, a thrust force to the aircraft structure (this is done in such a way that the aircraft structure is movable upwardly and away from the ground), and (C) be rotatable in opposite directions relative to each other, and (D) reduce (mitigate), at least in part, a horizontal rotational effect applied to the aircraft structure by the individual rotation of each of the first propeller assembly and the second propeller assembly. An engine assembly is configured to be supported by the aircraft structure. A transmission system is configured to: (A) be supported by the aircraft structure, and (B) be coupled (connected) to the engine assembly, and (C) be coupled (connected) to the first propeller assembly and the second propeller assembly (this is done in such a way that the transmission system, in use, urges the first propeller assembly and the second propeller assembly to be rotated once the engine assembly is activated), and (D) urge, in use, the first propeller assembly and the second propeller assembly to: (i) operatively rotate in opposite directions relative to each other, and (ii) operatively rotate at different rotational speeds relative to the rotational speed of the engine assembly. The result of the above arrangement is such that the different rotational speeds (the difference between the magnitudes of the rotational speeds) of the first propeller assembly and the second propeller assembly, in use, urge the aircraft structure to move (fly) along a desired path (flight path) relative to the ground.
To mitigate, at least in part, at least one problem associated with the existing technology, there is provided (in accordance with a second major aspect) an apparatus. The apparatus is for an aircraft structure. The aircraft structure includes a first propeller assembly and a second propeller assembly which are configured to: (A) be supported by the aircraft structure at a first propeller position and a second propeller position, respectively, and (B) impart, in use, a thrust force to the aircraft structure (this is done in such a way that the aircraft structure is movable upwardly and away from the ground), and (C) be rotatable in opposite directions relative to each other, and (D) reduce, at least in part, a horizontal rotational effect applied to the aircraft structure by the individual rotation of each of the first propeller assembly and the second propeller assembly, and an engine assembly that is configured to be supported by the aircraft structure. The apparatus includes (and is not limited to) a transmission system configured to be supported by the aircraft structure. The transmission system is also configured to be coupled (connected) to the engine assembly. The transmission system is also configured to be coupled (connected) to the first propeller assembly and the second propeller assembly. This is done in such a way that the transmission system, in use, urges the first propeller assembly and the second propeller assembly to be rotated once the engine assembly is activated. The transmission system is also configured to urge, in use, the first propeller assembly and the second propeller assembly to operatively rotate in opposite directions relative to each other. The transmission system is also configured to operatively rotate at different rotational speeds relative to the rotational speed of the engine assembly. The different rotational speeds of the first propeller assembly and the second propeller assembly, in use, urge the aircraft structure to fly along a desired flight path relative to the ground.
To mitigate, at least in part, at least one problem associated with the existing technology, there is provided (in accordance with a second major aspect) an apparatus. The includes: a transmission system configured to be supported by an aircraft structure, in which the aircraft structure includes: a first propeller assembly and a second propeller assembly which are configured to: (A) be supported by the aircraft structure at a first propeller position and a second propeller position, respectively, and (B) impart, in use, a thrust force to the aircraft structure in such a way that the aircraft structure is movable upwardly and away from the ground, and (C) be rotatable in opposite directions relative to each other, and (D) reduce, at least in part, a horizontal rotational effect applied to the aircraft structure by an individual rotation of each of the first propeller assembly and the second propeller assembly. In accordance with an option, there if further provided an engine assembly that is configured to be supported by the aircraft structure. In accordance with another option, the transmission system further configured to: be coupled to the engine assembly; and be coupled to the first propeller assembly and the second propeller assembly in such a way that the transmission system, in use, urges the first propeller assembly and the second propeller assembly to be rotated once the engine assembly is activated; and urge, in use, the first propeller assembly and the second propeller assembly to: operatively rotate in opposite directions relative to each other; and operatively rotate at different rotational speeds relative to a rotational speed of the engine assembly; and whereby the different rotational speeds of the first propeller assembly and the second propeller assembly, in use, urge the aircraft structure to fly along a desired flight path relative to the ground.
Other aspects are identified in the claims. Other aspects and features of the non-limiting embodiments may now become apparent to those skilled in the art upon review of the following detailed description of the non-limiting embodiments with the accompanying drawings. This Summary is provided to introduce concepts in simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the disclosed subject matter, and is not intended to describe each disclosed embodiment or every implementation of the disclosed subject matter. Many other novel advantages, features, and relationships will become apparent as this description proceeds. The figures and the description that follow more particularly exemplify illustrative embodiments.
The non-limiting embodiments may be more fully appreciated by reference to the following detailed description of the non-limiting embodiments when taken in conjunction with the accompanying drawings, in which:
The drawings are not necessarily to scale and may be illustrated by phantom lines, diagrammatic representations and fragmentary views. In certain instances, details unnecessary for an understanding of the embodiments (and/or details that render other details difficult to perceive) may have been omitted. Corresponding reference characters indicate corresponding components throughout the several figures of the drawings. Elements in the several figures are illustrated for simplicity and clarity and have not been drawn to scale. The dimensions of some of the elements in the figures may be emphasized relative to other elements for facilitating an understanding of the various disclosed embodiments. In addition, common, but well-understood, elements that are useful or necessary in commercially feasible embodiments are often not depicted to provide a less obstructed view of the embodiments of the present disclosure.
The following detailed description is merely exemplary and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure. The scope of the claim is defined by the claims (in which the claims may be amended during patent examination after the filing of this application). For the description, the terms “upper,” “lower,” “left,” “rear,” “right,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the examples as oriented in the drawings. There is no intention to be bound by any expressed or implied theory in the preceding Technical Field, Background, Summary or the following detailed description. It is also to be understood that the devices and processes illustrated in the attached drawings, and described in the following specification, are exemplary embodiments (examples), aspects and/or concepts defined in the appended claims. Hence, dimensions and other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless the claims expressly state otherwise. It is understood that the phrase “at least one” is equivalent to “a”. The aspects (examples, alterations, modifications, options, variations, embodiments and any equivalent thereof) are described regarding the drawings. It should be understood that the invention is limited to the subject matter provided by the claims, and that the invention is not limited to the particular aspects depicted and described. It will be appreciated that the scope of the meaning of a device configured to be coupled to an item (that is, to be connected to, to interact with the item, etc.) is to be interpreted as the device being configured to be coupled to the item, either directly or indirectly. Therefore, “configured to” may include the meaning “either directly or indirectly” unless specifically stated otherwise.
Referring to a first major embodiment as depicted in
Embodiments of the aircraft structure 102 are depicted in
The first propeller assembly 104 and the second propeller assembly 106 (embodiments of which are depicted in
The engine assembly 107 (embodiments of which are depicted in
The transmission system 110 may be called a power transmission system. The transmission system 110 (an embodiment of which is depicted in
In accordance with a preferred embodiment, the first propeller assembly 104 and the second propeller assembly 106, in use, contra-rotate relative to each other, and the elements of the transmission system 110, in use, counter-rotate relative to each other to negate rotational inertia effect on the aircraft structure 102.
The transmission system 110, in use, urges or causes (is configured to urge) the different rotational speeds (the difference between the magnitudes of the rotational speeds) of the first propeller assembly 104 and the second propeller assembly 106 so that the first propeller assembly 104 and the second propeller assembly 106, in use, urge the aircraft structure 102 to move (fly) along a desired path (flight path) relative to the ground.
Advantageously, by having the first propeller assembly 104 and the second propeller assembly 106 rotatable at different relative rotational speeds, the first propeller assembly 104 and the second propeller assembly 106, in use, urge movement of the aircraft structure 102 along a desired flight path depending on the tilt imposed on the aircraft structure 102 by the difference in rotational speeds between the first propeller assembly 104 and the second propeller assembly 106 (depending on the tilt imposed on the aircraft due to the relative rotational speeds between the first propeller assembly 104 and the second propeller assembly 106).
Referring to a second major embodiment as depicted in
The apparatus 100 includes and is not limited to (comprises) a transmission system 110 configured to be supported by the aircraft structure 102. The transmission system 110 is further configured to be coupled (connected) to the engine assembly 107. The transmission system 110 is further configured to be coupled (connected) to the first propeller assembly 104 and the second propeller assembly 106. This is done in such a way that the transmission system 110, in use, urges the first propeller assembly 104 and the second propeller assembly 106 to be rotated once the engine assembly 107 is activated. The transmission system 110 is further configured to urge, in use, the first propeller assembly 104 and the second propeller assembly 106 to operatively rotate in opposite directions relative to each other. Embodiments of the transmission system 110 are further configured to operatively rotate at different rotational speeds relative to the rotational speed of the engine assembly 107. It will be appreciated that not only do the propeller assemblies (104, 106) contra-rotate, the elements of the transmission system 110 also counter-rotate as well, which may negate rotational inertia effect on the aircraft structure 102. A gyroscopic method may be utilized for stabilization of the aircraft structure 102 during flight. A gyroscopic effect of the components of the transmission system 110 on the aircraft structure 102 may improve (at least in part) the stabilization and the maneuverability of the aircraft structure 102.
The transmission system 110, in use, urges or causes (is configured to urge) the different rotational speeds (the difference between the magnitudes of the rotational speeds) of the first propeller assembly 104 and the second propeller assembly 106 so that the first propeller assembly 104 and the second propeller assembly 106, in use, urge the aircraft structure 102 to move (fly) along a desired path (flight path) relative to the ground.
Referring to the embodiments as depicted in
Referring to the embodiment as depicted in
The transmission system 110 further includes (and is not limited to) a first variable-velocity assembly 224 configured to be coupled (either directly or indirectly) to an output of the first power conversion assembly 214. This is done in such a way that the first power conversion assembly 214, in use, rotates the first variable-velocity assembly 224. For instance,
The transmission system 110 further includes (and is not limited to) a first transmission output assembly 234 configured to (A) couple to an output of the first variable-velocity assembly 224, and (B) couple to the first propeller assembly 104. This is done in such a way that the first variable-velocity assembly 224, in use, rotates the first transmission output assembly 234, and the first transmission output assembly 234, in use, rotates the first propeller assembly 104. For instance
The transmission system 110 further includes (and is not limited to) a second power conversion assembly 216 configured to be coupled (either directly or indirectly) to an output of the engine assembly 107. This is done in such a way that the engine assembly 107, in use, rotates the second power conversion assembly 216. For instance,
Referring to the embodiment as depicted in
The transmission system 110 further includes (and is not limited to) a second transmission output assembly 236 configured to (A) couple to an output of the second variable-velocity assembly 226, and (B) couple to the second propeller assembly 106. This is done in such a way that the second variable-velocity assembly 226, in use, rotates that the second transmission output assembly 236, and the second transmission output assembly 236, in use, rotates the second propeller assembly 106. For instance,
Referring to the embodiment as depicted in
Referring to the embodiment as depicted in
Preferably, the transmission system 110 further includes (and is not limited to) an input shaft coupler 201 (such as a beveled gear portion and any equivalent thereof), a transmission input shaft assembly 202, a contra-rotating mechanism 208 (such as a contra-rotating gearbox assembly and any equivalent thereof), a transmission shaft support assembly 209, a first power conversion assembly 214, a second power conversion assembly 216, a first variable-velocity assembly 224, a second variable-velocity assembly 226, a first transmission output assembly 234, and a second transmission output assembly 236.
The first power conversion assembly 214 is configured to feed mechanical power to the first variable-velocity assembly 224, which then feeds mechanical power to the first propeller assembly 104.
The second power conversion assembly 216 is configured to feed mechanical power to the second variable-velocity assembly 226, which then feeds mechanical power to the second propeller assembly 106.
The input shaft coupler 201 is configured to be coupled to the engine output coupler 111. This is done in such a way that the input shaft coupler 201 is rotatable once the engine output coupler 111 is made to rotate (by activation of the engine assembly 107). The input shaft coupler 201 may include a shaft gear. The input shaft coupler 201 may include a 90-degree shaft gear.
The transmission input shaft assembly 202 is affixed to the input shaft coupler 201. This is done in such a way that the transmission input shaft assembly 202 is made to rotate once the input shaft coupler 201 is made to rotate.
The contra-rotating mechanism 208 is coupled to (mounted to) a portion of the transmission input shaft assembly 202, and is spaced apart from the input shaft coupler 201. The contra-rotating mechanism 208 is supported by the transmission input shaft assembly 202 and in turn by the transmission shaft support assembly 209 (such as bearing devices, etc.).
Details regarding the specific embodiment and aspects of the contra-rotating mechanism 208 are depicted in
The transmission shaft support assembly 209 is configured to support the rotation of the transmission input shaft assembly 202. The transmission shaft support assembly 209 is configured to support simultaneous rotation of the first transmission input shaft 204 and the second transmission input shaft 206 relative to each other.
The first power conversion assembly 214 is configured to be coupled to (for utilization of, or for rotating) the first transmission output assembly 234 (which in turn is coupled to the first propeller assembly 104 as depicted in
The second power conversion assembly 216 is configured to be coupled to (for utilization of, or for rotating) the second transmission output assembly 236 (which in turn is coupled to the second propeller assembly 106 as depicted in
The first variable-velocity assembly 224 is configured to be coupled to the first propeller assembly 104. The second variable-velocity assembly 226 is configured to be coupled to the second propeller assembly 106. It will be appreciated that the components of the first variable-velocity assembly 224 may be similar to the components of the second variable-velocity assembly 226.
The first variable-velocity assembly 224 includes a first input shaft 503 and a first output shaft 509. The second variable-velocity assembly 226 includes a second input shaft 523 and a second output shaft 529. The first variable-velocity assembly 224 and the second variable-velocity assembly 226 may each include a continuously variable transmission (CVT). The continuously variable transmission (also known as a single-speed transmission, stepless transmission, pulley transmission, or, in case of motorcycles, a twist-and-go) is an automatic transmission that may change seamlessly through a continuous range of effective gear ratios. The flexibility of a CVT allows the input shafts (the first input shaft 503 and the second input shaft 523) to maintain a constant angular velocity while the output shafts (the first output shaft 509 and the second output shaft 529) may be varied (may have variable rotational speeds, relative to the input shaft 108 of the engine assembly 107).
The first transmission output assembly 234 is configured to be coupled to the first propeller assembly 104. The second transmission output assembly 236 is configured to be coupled to the second propeller assembly 106. The first transmission output assembly 234 and the second transmission output assembly 236 are configured to be rotatable in opposite directions relative to each other. It will be appreciated that components of the first transmission output assembly 234 may be the same as the components of the second transmission output assembly 236.
Referring to the embodiments as depicted in
Referring to the embodiment as depicted in
Referring to the embodiments as depicted in
Referring to the embodiment as depicted in
Referring to the embodiment as depicted in
The second variable-velocity assembly 226 (for the second propeller assembly 106) includes (and is not limited to) components that are similar to the components of the first variable-velocity assembly 224 (such as a second driving pulley 521, a second input shaft 523, a second coupling device 525, a second driven pulley 527, a second output shaft 529, and a second shaft coupler 531).
The first transmission output assembly 234 is for the first propeller assembly 104. The second transmission output assembly 236 is for the second propeller assembly 106. The first transmission output assembly 234 includes (and is not limited to) a first transmission-shaft support structure 601, a first extension shaft 603 (also called a shaft segment), a first variable angle shaft coupler 605, a first shaft portion 607, and a first variable-length shaft assembly 609. The first transmission-shaft support structure 601 is configured to support rotation of the first extension shaft 603. The first extension shaft 603 is configured to rotate once the first shaft coupler 511 is made to rotate. The first variable angle shaft coupler 605 is configured to couple the first extension shaft 603 to the first shaft portion 607. The first variable-length shaft assembly 609 is attached to the end portion of the first shaft portion 607. The first variable-length shaft assembly 609 is configured to be coupled to the first propeller assembly 104 (as depicted in
The transmission system 110 is configured to operate (that is, deliver mechanical power or energy to) each of the propellers of the aircraft structure 102 (as depicted in
A variation in the number of outputs, or of the ratio between an output of the contra-rotating mechanism 208 and inputs to the first variable-velocity assembly 224 and the second variable-velocity assembly 226 allows for the operation of more [pairs of] propeller assemblies, with an increase in velocity and a reduction of torque received by the propeller assemblies upon operation of the transmission system 110 (with power input from the engine assembly 107).
The contra-rotating mechanism 208 is configured for distribution of mechanical power in opposite rotational directions (for each of the first propeller assembly 104 and the second propeller assembly 106). More specifically, the contra-rotating mechanism 208 is configured to operate the first power conversion assembly 214 (as depicted in
A technical advantage for the transmission system 110 is that the engine assembly 107 may provide all the required mechanical power for utilization by the propellers of the aircraft structure 102 (as depicted in
Referring to the preferred embodiment as depicted in
It will be appreciated that the transmission controller 223 is configured to cooperate with the first variable-velocity assembly 224 and/or the second variable-velocity assembly 226 (depicted in of
Referring to the preferred embodiment as depicted in
Referring to the preferred embodiment as depicted in
The second operation 712 includes instructing the transmission controller 223 to control (control the operation of) the first variable-velocity assembly 224 and the second variable-velocity assembly 226 based on the flight data 225 that was received. This is done in such a way that the transmission controller 223, in use, urges the first variable-velocity assembly 224 and the second variable-velocity assembly 226 to move the first propeller assembly 104 and the second propeller assembly 106 (respectively) so that the first propeller assembly 104 and the second propeller assembly 106 (A) operatively rotate in opposite directions relative to each other, and (B) operatively rotate at different rotational speeds relative to a rotational speed of the engine assembly 107. This is done in such a way that the different rotational speeds of the first propeller assembly 104 and the second propeller assembly 106, in use, urge the aircraft structure 102 to fly along a flight path relative to the ground (based on the flight data 225 that was received by the transmission controller 223).
Referring to the embodiment as depicted in
The transmission input shaft assembly 202 includes a first transmission input shaft 204 (outer input shaft assembly, as depicted in the embodiment of
The input shaft coupler 201 is affixed to the second transmission input shaft 206. The second transmission input shaft 206 is affixed to an input of the contra-rotating mechanism 208. The first transmission input shaft 204 is affixed to an output of the contra-rotating mechanism 208. The first power conversion assembly 214 (such as the first input conversion gear 301) is affixed to the first transmission input shaft 204. The second power conversion assembly 216 (such as the second input conversion gear 311) is affixed to the second transmission input shaft 206.
The first transmission input shaft 204 and the second transmission input shaft 206 are configured to counter rotate relative to each other once the contra-rotating mechanism 208 is made to operate (by the rotation of the second transmission input shaft 206). The first input conversion gear 301 (that is, the first power conversion assembly 214) and the second input conversion gear 311 (that is, the second power conversion assembly 216) are configured to counter rotate relative to each other once the contra-rotating mechanism 208 is made to operate (by the rotation of the second transmission input shaft 206).
Referring to the embodiments as depicted in
The following is offered as further description of the embodiments, in which any one or more of any technical feature (described in the detailed description, the summary and the claims) may be combinable with any other one or more of any technical feature (described in the detailed description, the summary and the claims). It is understood that each claim in the claims section is an open ended claim unless stated otherwise. Unless otherwise specified, relational terms used in these specifications should be construed to include certain tolerances that the person skilled in the art would recognize as providing equivalent functionality. By way of example, the term perpendicular is not necessarily limited to 90.0 degrees, and may include a variation thereof that the person skilled in the art would recognize as providing equivalent functionality for the purposes described for the relevant member or element. Terms such as “about” and “substantially”, in the context of configuration, relate generally to disposition, location, or configuration that are either exact or sufficiently close to the location, disposition, or configuration of the relevant element to preserve operability of the element within the invention which does not materially modify the invention. Similarly, unless specifically made clear from its context, numerical values should be construed to include certain tolerances that the person skilled in the art would recognize as having negligible importance as they do not materially change the operability of the invention. It will be appreciated that the description and/or drawings identify and describe embodiments of the apparatus (either explicitly or inherently). The apparatus may include any suitable combination and/or permutation of the technical features as identified in the detailed description, as may be required and/or desired to suit a particular technical purpose and/or technical function. It will be appreciated that, where possible and suitable, any one or more of the technical features of the apparatus may be combined with any other one or more of the technical features of the apparatus (in any combination and/or permutation). It will be appreciated that persons skilled in the art would know that the technical features of each embodiment may be deployed (where possible) in other embodiments even if not expressly stated as such above. It will be appreciated that persons skilled in the art would know that other options would be possible for the configuration of the components of the apparatus to adjust to manufacturing requirements and still remain within the scope as described in at least one or more of the claims. This written description provides embodiments, including the best mode, and also enables the person skilled in the art to make and use the embodiments. The patentable scope may be defined by the claims. The written description and/or drawings may help to understand the scope of the claims. It is believed that all the crucial aspects of the disclosed subject matter have been provided in this document. It is understood, for this document, that the word “includes” is equivalent to the word “comprising” in that both words are used to signify an open-ended listing of assemblies, components, parts, etc. The term “comprising”, which is synonymous with the terms “including,” “containing,” or “characterized by,” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. Comprising (comprised of) is an “open” phrase and allows coverage of technologies that employ additional, unrecited elements. When used in a claim, the word “comprising” is the transitory verb (transitional term) that separates the preamble of the claim from the technical features of the invention. The foregoing has outlined the non-limiting embodiments (examples). The description is made for particular non-limiting embodiments (examples). It is understood that the non-limiting embodiments are merely illustrative as examples.