Abstract:
A rotor blade system includes a first hub assembly having a first set of rotor blades and rotatably attached to a rotor mast, a second hub assembly having a second set of rotor blades and rotatably attached to the rotor mast, the second hub assembly being positioned at a space relative to the first hub assembly, a torque splitter device engaged with both the first hub assembly and the second hub assembly, and a locking device operably associated with the torque splitter device. The method includes rotating the first hub relative to the second hub via the torque splitter until the first set of rotor blades align with the second set of rotor blade about a common horizontal axis.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present application relates generally to duel plane rotor systems, and more specifically, to a duel plane rotor system blade having scissoring folding features. 
         [0003]    2. Description of Related Art 
         [0004]    Duel plane rotor systems for helicopters are well known in the art and are necessary systems to create flight. The conventional duel plane rotor systems include two rotor hub assemblies positioned one above the other and configured to counter-rotate a plurality of rotor blades associated with each hub assembly. The duel plane stacked rotor system is well known and also the feature of scissoring the hub assemblies relative to each other for storage and transport. For example, the rotors may need to fold relative to each other to reduce their footprint for shipboard use and/or to stow in a hanger. 
         [0005]    Although the foregoing developments in the field of rotor systems represent great strides, however many shortcomings remain. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0006]    The novel features believed characteristic of the embodiments of the present application are set forth in the appended claims. However, the embodiments themselves, as well as a preferred mode of use, and further objectives and advantages thereof, will best be understood by reference to the following detailed description when read in conjunction with the accompanying drawings, wherein: 
           [0007]      FIG. 1  is a side view of a helicopter according to a preferred embodiment of the present application; 
           [0008]      FIG. 2  is a perspective view of a tiltrotor aircraft according to an alternative embodiment of the present application; 
           [0009]      FIG. 3  is an oblique view of a rotor blade system in accordance with a preferred embodiment of the present application; 
           [0010]      FIG. 4  is a side view of the rotor blade system of  FIG. 3 ; 
           [0011]      FIG. 5  is an oblique partial view of the rotor system of  FIG. 3 ; 
           [0012]      FIGS. 6 and 7  are exploded oblique views of the rotor system of  FIG. 3 ; and 
           [0013]      FIGS. 8 and 9  are simplified front views of torque splitter devices in accordance with an alternative embodiment of the present application. 
       
    
    
       [0014]    While the system and method of the present application is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular embodiment disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the process of the present application as defined by the appended claims. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0015]    Illustrative embodiments of the apparatus and method are provided below. It will of course be appreciated that in the development of any actual embodiment, numerous implementation-specific decisions will be made to achieve the developer&#39;s specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. 
         [0016]    The system of the present application overcomes problems commonly associated with conventional rotor systems. Specifically, the rotor system of the present application is provided with and utilizes an torque splitter devices associated with each rotor hub assembly to allow the hub assemblies to move relative to each other such that the blades of the hub assemblies are stacked in the same horizontal plane as each other. Further detailed description of these features are provided below and illustrated in the accompanying drawings. 
         [0017]    The system and method of the present application will be understood, both as to its structure and operation, from the accompanying drawings, taken in conjunction with the accompanying description. Several embodiments of the system are presented herein. It should be understood that various components, parts, and features of the different embodiments may be combined together and/or interchanged with one another, all of which are within the scope of the present application, even though not all variations and particular embodiments are shown in the drawings. It should also be understood that the mixing and matching of features, elements, and/or functions between various embodiments is expressly contemplated herein so that one of ordinary skill in the art would appreciate from this disclosure that the features, elements, and/or functions of one embodiment may be incorporated into another embodiment as appropriate, unless described otherwise. 
         [0018]    Referring now to the drawings wherein like reference characters identify corresponding or similar elements throughout the several views,  FIG. 1  depicts an aircraft  101  in accordance with a preferred embodiment of the present application. In the exemplary embodiment, aircraft  101  is a helicopter having a fuselage  103  and a rotor system  105  carried thereon. A plurality of rotor blades  107  is operably associated with rotor system  105  for creating flight. In the exemplary embodiment, aircraft  101  includes two rotor hub assemblies each having two blades. The rotor assemblies are configured to counter-rotate relative to each other during flight. 
         [0019]    Although shown associated with a helicopter, it will be appreciated that the system of the present application could also be utilized with different types of rotary aircraft and vehicles. For example,  FIG. 2  illustrates a tiltrotor aircraft  201  that utilizes the system in accordance with the present application. 
         [0020]    Tiltrotor aircraft  201  includes rotor assemblies  213   a  and  213   b  that are carried by wings  215   a  and  215   b,  and are disposed at end portions  216   a  and  216   b  of wings  215   a  and  215   b,  respectively. Tilt rotor assemblies  213   a  and  213   b  include nacelles  220   a  and  220   b , which carry the engines and transmissions of tilt rotor aircraft  201 , as well as, rotor proprotors  219   a  and  219   b  on forward ends  221   a  and  221   b  of tilt rotor assemblies  213   a  and  213   b,  respectively. Tilt rotor assemblies  213   a  and  213   b  move or rotate relative to wing members  215   a  and  215   b  between a helicopter mode in which tilt rotor assemblies  213   a  and  213   b  are tilted upward, such that tilt rotor aircraft  201  flies like a conventional helicopter; and an airplane mode in which tilt rotor assemblies  213   a  and  213   b  are tilted forward, such that tilt rotor aircraft  201  flies like a conventional propeller driven aircraft. Like aircraft  101 , in the contemplated embodiment, aircraft  201  includes two rotor hub assemblies having three blades each and stacked relative to each other. Thus, it will be appreciated that the features discussed herein could be utilized on rotor assemblies having two or more blades. 
         [0021]    Referring now to  FIGS. 3 and 4  in the drawings, respective oblique and side views of a rotor system  301  are shown. In the preferred embodiment, rotor system  301  includes an upper rotor hub assembly  303  having two rotor blades  305 ,  307  and a lower rotor hub assembly  309  having two rotor blades  311 ,  313 . During use, the rotor assemblies  303 ,  309  are rotatably attached to and configured to counter-rotate relative to each other about a mast  315 . 
         [0022]    In  FIG. 5 , a partial oblique view of system  301  is shown. During flight, an torque splitter device  501  is used to control the rotational movement of the hub assemblies  303 ,  309  relative to each. For example, it should be understood that the hub assemblies experience lead-lag movement, thus requiring the use of slight movement of the rotational movement of the hub assemblies relative to each other, which is turn is controlled via that torque splitter device  501 . In the contemplated embodiment, a locking device  503  is operably associated with torque splitter device  501  to control the rotational movement of the hub assemblies relative to each other during flight. It will be appreciated that during the scissoring process of positioning the blade on the same horizontal plane, as depicted in  FIG. 4 , the locking device  503  unlocks the torque splitter device  501 , which in turn enables the rotor hub assemblies  303 ,  309  to move freely relative to each other. 
         [0023]    It is also contemplated having an actuator  505  operably associated with torque splitter device  501  and configured to rotate the torque splitter device, which in turn rotates the rotor hub assemblies to a position wherein the rotor blades are stacked in the same horizontal plane, as depicted in  FIG. 4 , during storage, and likewise rotated such that the blades are offset relative to each other, as depicted in  FIG. 3 . The actuator  505  in turn is controlled by a computer  507  manually or autonomously controlled by the user. 
         [0024]    In  FIGS. 6 and 7 , exploded oblique views of system  301  are shown. Not all components of system  301  are shown, e.g., the rotor blades, for clarity. 
         [0025]    Hub assembly  303  includes a hub  601  configured to secure the rotor blades  305 ,  307  to mast  315 , while hub assembly  309  includes a hub  603  configured to secure the rotor blades  311 ,  313  to mast  315 . The rotor hub assemblies  303 ,  309  are secured to the mast  315  via respective sleeves  605 ,  607 , which in turn are configured to engage with mast  315  and rotate the hub assemblies. 
         [0026]    It will be appreciated that system  301  includes two torque splitter devices  501  and  502 , each device being positioned at different locations about mast  315  and substantially similar in form and function. 
         [0027]    Torque splitter device  501  includes a base  608  having three openings  609 ,  611 , and  613  extending through the thickness of the base  608  and configured to receive respective shafts  619 ,  623 , and  625  of respective sleeves  605 ,  620 , and  607 . The torque splitter device  501  is further provided with two bearings  615 ,  617  that engages with respective openings  609 ,  613 . 
         [0028]    During operation, the torque splitter device  501  is configured to rotate about shaft  623  with opening  611 . It should be understood that sleeve  620  fixedly rotates with mast  315  during flight, while the sleeves  605 ,  607  can be rotationally offset relative to sleeve  620  during flight due to lead-lag movement of the hub assemblies. 
         [0029]    Referring now to  FIGS. 8 and 9 , simplified front views of torque splitter devices in accordance with an alternative embodiment of the present application are shown. It will be appreciated that the features of system  301  discussed herein are used with different types of torque splitter devices, for example, an torque splitter device  801 , which is configured to extend the overall rotational movement of the hub assemblies relate to each other. This feature is achieved with openings  805 ,  809  configured to receive shafts  619 ,  625  therethrough. The openings allow the shafts to slide therein, which in turn extends the overall movement of the hub assemblies relative to each other. Thus, in the contemplated embodiment, torque splitter device  801  includes a body  803  with openings  805 ,  809 , along with opening  807  extending through the thickness. In the contemplated embodiment, one or more fastening means, for example, fasteners  802 ,  804  are configured to slidingly engage with respective openings  805 ,  809 . 
         [0030]    In  FIG. 9 , it is also contemplated having an extension member  901  that engages with, for example, the shaft  619  about a first fastening means  907  and opening  805  about a second fastening means  905  that in turn are held together with an elongated body  903 . The extension member  901  is configured to extend the overall movement of the hub assemblies relative to each other. It will be appreciated that although shown associated with torque splitter device  801 , the extension member  901  could be used with other types of torque splitter devices, including torque splitter device  501 . 
         [0031]    It is apparent that a system and method with significant advantages has been described and illustrated. The particular embodiments disclosed above are illustrative only, as the embodiments may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. It is therefore evident that the particular embodiments disclosed above may be altered or modified, and all such variations are considered within the scope and spirit of the application. Accordingly, the protection sought herein is as set forth in the description. Although the present embodiments are shown above, they are not limited to just these embodiments, but are amenable to various changes and modifications without departing from the spirit thereof.