Abstract:
The electrical harness system is configured for routing a harness between a rotor yoke and a rotor blade. A recess in an inboard cap member is configured to house a connector and an associated harness. As the recess extends along a radial path in the chordwise direction of the rotor blade, the harness is configured to lie within the recess. Operationally induced centrifugal forces promote positioning the slack of harness within the recess, while the slack in the harness remains available for relative dynamic movements between the rotor blade and the rotor yoke. Such a routing of the harness reduces aerodynamic drag and minimizes damage that could otherwise occur to the harness.

Description:
BACKGROUND 
     1. Technical Field 
     The present application relates in general to an electrical wiring system for a rotor hub. 
     2. Description of Related Art 
     Certain aircraft include systems associated with a rotating airfoil, such as a rotor blade, that can require electrical power. For example, a rotor blade de-ice system can require electrical power. Conventionally, power is routed to the rotor blade with exposed brackets on the leading edge of the blade to mount an electrical connector. Such a configuration typically causes the bracket to extend out of the rotor blade contour and leaving the wiring harness exposed beyond the profile of the rotor hub. Part of the wiring harness is loose and must be handled carefully during manufacturing and when disconnected from the aircraft. Such a harness configuration increases the rotor hub drag and the vulnerability of the connector to foreign object damage (FOD). Such a configuration can further cause the harness to have a substantial loop in order to carry all the flap, lead/lag, and pitch motions while the centrifugal forces tend to pull the harness outward. 
     There is a need for an improved wiring system between the rotor hub and the rotor blade. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the system of the present disclosure are set forth in the appended claims. However, the system itself, 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: 
         FIG. 1  is a side view of a rotorcraft, according to an embodiment of the present application; 
         FIG. 2  is a view looking down on the rotor hub portion, according to an embodiment of the present application; 
         FIG. 3  is a detail view of the rotor hub portion, according to an embodiment of the present application; 
         FIG. 4  is a cross-sectional view taken at section lines IV-IV in  FIG. 3 , according to an embodiment of the present application; 
         FIG. 5  is a perspective view of the wiring system, according to an embodiment of the present application; and 
         FIG. 6  is a perspective view of the wiring system, according to an embodiment of the present application. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Illustrative embodiments of the system of the present disclosure are described below. In the interest of clarity, all features of an actual implementation may not be described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must 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. 
     In the specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the present disclosure, the devices, members, apparatuses, etc. described herein may be positioned in any desired orientation. Thus, the use of terms such as “above,” “below,” “upper,” “lower,” or other like terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the device described herein may be oriented in any desired direction. 
     Referring to  FIG. 1  in the drawings, a rotorcraft  102  is illustrated. Rotorcraft  102  has a rotor system  101  with a plurality of rotor blades  103 . Rotorcraft  102  further includes a fuselage  104 , landing gear  106 , and an empennage  108 . A main rotor control system can be used to selectively control the pitch of each rotor blade  103  in order to selectively control direction, thrust, and lift of rotorcraft  102 . It should be appreciated that even though the system of the present application is depicted on a rotorcraft  102  having certain illustrated features, it should be appreciated that the system of the present application can be implemented on other aircraft and aircraft configurations, as one of ordinary skill in the art would fully appreciate having the benefit of this disclosure. 
     Referring to  FIG. 2 , rotor hub  101  includes a plurality of rotor blades  103  coupled to a central yoke  109 , via a rotor grip  107 . Yoke  109  is coupled to a rotor mast  105  such that rotation of rotor mast  105 , in a direction  113 , causes the yoke  109  and rotor blades  103  to rotate about the rotor mast axis of rotation. It should be appreciated that even though rotor hub  101  is illustrated with four rotor blades  103 , the system of the present application is equally applicable to rotor hubs having an alternative number of rotor blades  103 . 
     Referring now also to  FIGS. 3-6 , an electrical wiring system  301  is illustrated. System  301  is configured for the routing of electrical lines in a dynamic environment. In the illustrated embodiment, system  301  includes a wiring harness  303   a  routed between a powered unit  305  and a connector  313   a . System  301  further includes a connector  313   b  and wiring harness  303   b . One feature of system  301  is a contoured recess  307  in a cap member  311  located at the root end of spar  309 . In the illustrated embodiment, spar  309  is a partially hollow member; however, cap member  311  functions in part to seal off the interior portion of spar  309 . Connectors  313   a  and  313   b  allows the wiring harness  303   a  to be routed in the interior of rotor blade  103  to powered unit  305 , thus protecting harness  303   a  from damage. In the illustrated embodiment, powered unit  305  is a de-icing heater blanket; however, it should be appreciated that powered unit  305  can be any power consuming device, such as a light, an actuator for a moveable airfoil, or a vibration reduction system, to name a few examples. Further, harnesses  303   a  and  303   b  can alternatively be hydraulic hoses instead of power wire harnesses. Further, harnesses  303   a  and  303   b  can provide a data or control signal in addition or in lieu of providing power. For example, harnesses  303   a  and  303   b  can provide hydraulic power to a hydraulic actuator in rotor blade  103 . 
     Harness  303   b  can be secured with one or more harness clips located within recess  307 . Recess  307  forms a contoured radius along the chordwise direction at the root end portion of cap member  311 . Recess  307  and harness  303   b  are configured such that an operationally generated centrifugal force  315  acts to position a slack portion of harness  303   b  into the trailing edge side of recess  307 . A slack portion of harness  303   b  can be necessary to compensate for all the flap, lead/lag, and pitch motions of rotor blade  103 . In the illustrated embodiment, the harness  303   b  is routed away from the body of the rotor blade  103  toward a lead/lag damper  317 ; however, it should be appreciated that an alternative embodiment may not include lead/lag damper  317 . Harness  303   b  is routed along the axis of lead/lag damper  317 , and further extends back towards the axis of rotation. A loop or slack in the harness  303   b  can be implemented where the lead/lag damper  317  joins yoke  109 , allowing for relative motion therebetween. 
     System  301  is configured to minimize aerodynamic drag penalties that may otherwise be associated with conventional harness routing. Further, system  301  allows connectors  313   a  and  313   b , and its terminals, to be enclosed in recess  307  of blade  103 , away from potential environmental damage. Further, potential manufacturing damage to harness  303   a  is reduced by reducing the exposed amount of harness  303   a . Further, coupling harness  303   b  to the blade portion harness  303   a  at connectors  313   a  and  313   b  reduces damage to may otherwise occur to conventional wire attachments that are susceptible to fatigue induced breakage. Connector  313   a  is mounted on a wall  321  near a leading edge portion of recess  307 . Wall  321  can be a flat surface suitable for mounting connector  313   a . In the illustrated embodiment, wall  321  is approximately normal to an inner surface of recess  307  such that the harness  303   b  is directed inboard toward the rotor mast until approximately reaching a centerline  100  of the root end, in which recess  307  is contoured in an outboard direction until reaching the trailing edge termination. This trailing edge portion of recess  307  provides a secure housing for the slack portion of harness  303   b  as centrifugal forces acts upon harness  303   b.    
     In the illustrated embodiment, rotor blade  103  is coupled to rotor grip  107  with bolts  319   a  and  319   b . It can be particularly desirable to fold and stow rotor blades  103 . System  301  is configured to allow folding of rotor blade  103  without having to disconnect connectors  313   a  and  313   b  from each other. For example, bolt  319   b  can be removed such that rotor blade  103  is allowed to rotate about bolt  319   a  in a rotation R 1 . In such a configuration, when rotor blade  103  is rotated towards its leading edge, slack in harness  303   b  is generated and allowed to build within recess  307 . Such a configuration of system  301  saves time and maintenance costs associated with disconnecting a harness for rotor blade folding. 
     The particular embodiments disclosed herein are illustrative only, as the system may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Modifications, additions, or omissions may be made to the system described herein without departing from the scope of the invention. The components of the system may be integrated or separated. Moreover, the operations of the system may be performed by more, fewer, or other components. 
     Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. 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 disclosure. Accordingly, the protection sought herein is as set forth in the claims below. 
     To aid the Patent Office, and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants wish to note that they do not intend any of the appended claims to invoke paragraph 6 of 35 U.S.C. §112 as it exists on the date of filing hereof unless the words “means for” or “step for” are explicitly used in the particular claim.