Abstract:
A propeller device for aircraft, spacecraft or watercraft comprising two or more blades and a spinner. The blades are arranged on a hub so that they can be in a deployed or a retracted position. The spinner comprises first, second and third movable portions configured for allowing deploying or retracting the blades and for keeping the blades deployed or retracted.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the European patent application No. 15382447.9 filed on Sep. 11, 2015, the entire disclosures of which are incorporated herein by way of reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to propeller devices for aircraft, spacecraft or watercraft and, in particular, to propeller devices with deployable/retractable blades. 
       BACKGROUND OF THE INVENTION 
       [0003]    There are different applications in the aeronautic industry in which a deployable propeller is foreseen, like Emergency Ram Air Turbines in commercial airplanes or self-motorized gliders. In commercial aircraft, an Emergency Ram Air Turbine is a system that allows getting power from external airstream in a multiple engine failure case deploying a propeller device from, usually, a dedicated fairing or pod. In the case of gliders, in order to avoid dependency from another engine powered aircraft for take-off, some solutions to deploy and/or to fold again the propeller in flight are known. 
         [0004]    There are also applications in watercraft where a deployed propeller is desirable as for minimizing water drag in wing sailing boats and others. 
         [0005]    In all the cases, the propeller needs to remain folded and hidden while it is not needed, in order to minimize the drag, and it is unfolded or deployed when required to allow for thrust. 
         [0006]    Known solutions for folding and unfolding a propeller are described in U.S. Pat. No. 2,021,481 “Folding Propeller,” U.S. Pat. No. 2,198,475 “Collapsible Propeller for Airplanes,” U.S. Pat. No. 2,500,382 “Folding Propeller” and U.S. Pat. No. 6,152,693 “A Folding Propeller” dedicated to vessels and sailing ships. 
         [0007]    U.S. Pat. No. 2,848,054 “Aeronautical Propeller Spinner” describes a ventilation system inside the spinner of a propeller device. 
         [0008]    U.S. Pat. No. 7,886,544 B2 “Propeller or Propeller Drive” describes both propeller drives and folding propeller methods. 
         [0009]    However, there are not known propeller devices for aircraft, spacecraft or watercraft able to deploy or retract the blades while moving in flight or water. 
       SUMMARY OF THE INVENTION 
       [0010]    In one aspect, the invention provides a propeller device comprising two or more blades mounted on a hub connected to a driving shaft defining a longitudinal axis and a forward spinner (that will be also called, simply, spinner in this specification). The mounting arrangement of the blades on the hub is configured for arranging the blades whether in a deployed position or in a retracted position inside the forward spinner. The forward spinner comprises a first movable portion in the direction of the longitudinal axis and a second rotatory portion around the longitudinal axis from a closed position to an open position and vice versa that are configured for allowing deploying or retracting the blades and for keeping the blades deployed or retracted. The outer surface of the first movable portion comprises slots suitably dimensioned for allowing passage of the blades through them. The outer surface of the second rotatory portion is formed by first slot covers. The forward spinner further comprises a third rotatory portion around the longitudinal axis from a closed position to an open position with an outer surface formed by second slot covers. 
         [0011]    In an embodiment, the first movable portion comprises a supporting frame and first and second guiding means cooperating with rolling devices placed in other spinner components to control its translational movement. 
         [0012]    In an embodiment, the second rotatory portion comprises forward and rear supporting frames and cooperating rolling means. 
         [0013]    In another aspect, the invention provides aircraft -including unmanned aerial vehicles (UAV&#39;s)-, spacecraft and watercraft with the propeller device. 
         [0014]    Other desirable features and advantages of this invention will become apparent from the subsequent detailed description of the invention and the appended claims, in relation with the enclosed drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1 a    is a perspective view illustrating the propeller device of the invention with the blades retracted inside the outer surface of the spinner and  FIG. 1 b    is an enlarged view of  FIG. 1 a    with one fourth of the outer surface of the spinner removed for clarity purposes. 
           [0016]      FIG. 2  is the same view of  FIG. 1 b    with the first movable portion of the spinner removed for clarity purposes. 
           [0017]      FIG. 3 a    is a perspective view illustrating the propeller device of the invention with the blades being deployed and  FIG. 3 b    is an enlarged view of  FIG. 3 a    with one fourth of the outer surface of the spinner removed for clarity purposes. 
           [0018]      FIG. 4 a    is a perspective view illustrating the propeller device of the invention with the blades fully deployed and  FIG. 4 b    is an enlarged view of  FIG. 4 a    with one fourth of the outer surface of the spinner removed for clarity purposes. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    This invention relates to a structure of the spinner  21  of a propeller device for aircraft, UAV&#39;s, spacecraft or watercraft that allows that the blades  11  can be deployed from a retracted position inside the forward spinner  21 , in a longitudinal direction, to a deployed position and that they can be retracted from the deployed position to the retracted position. The blades  11  are mounted in a hub  13  connected to a motor or generator shaft (not shown in the Figures). 
         [0020]    Typically, the spinner  21  has a so-called generic conical shape. It can also have the shape of a surface of revolution created by a curve that grows continuously with respect to the revolution axis. 
         [0021]    The spinner  21  comprises first, second and third movable portions  23 ,  25 ,  27 . 
         [0022]    The outer surface  33  of the first movable portion  23  includes slots  34  (see  FIG. 3 a   ) to allow the deployment and retraction of blades  11 , the outer surface of the second portion  25  is formed by first slot covers  36  to cover the slots  34  less the spaces  41  (see  FIG. 3 b   ) occupied by the blades  11  in their deployed position and the outer surface of the third movable portion  27  is formed by second slot covers  42  to cover the spaces  41 . 
         [0023]    The outer surface of the spinner  21  is, then, formed by the outer surfaces of the first, second and third movable portions  23 ,  25 ,  27  when the blades are retracted (see  FIG. 1 a   ) and by the outer surfaces of the first and second movable portions  23 ,  25  when the blades are deployed (see  FIG. 4 a   ). 
         [0024]    The basic components of the first movable portion  23 , in addition to the outer surface  33 , are: a supporting frame  51  of the first movable portion, guiding means  53 ,  55  for controlling the translational movement in the direction of the longitudinal axis  15  and driving means to perform translational movement of the first movable portion (not shown in the Figures). 
         [0025]    The basic components of the second movable (rotatory) portion  25 , in addition to the first slot covers  36  forming an outer surface of the second movable portion, are forward and rear supporting frames  71 ,  73  of the first slot covers  36  as well as rolling means  75  and driving means (not shown in the Figures) to perform rotatory movement of the second movable portion. 
         [0026]    The basic components of the third movable (rotatory) portion  27 , in addition to the second slot covers  42  forming an outer surface of the third movable portion, are supporting frames and driving means (not clearly shown in the Figures) to perform the rotatory movement of the third movable portion. 
         [0027]    The spinner  21  also comprises roller devices  57 ,  59  for cooperating with the guiding means  53 ,  55 , placed, respectively, in the supporting frame  71  of the second movable portion  25  and in the hub  13 . As the roller device  57  is placed in the second movable portion  25  the roller device serves to coordinate the translational movement of the first movable portion  23  with the rotatory movement of the second movable portion  25 . 
         [0028]    To allow the deployment/retraction of the blades  11 , the first movable portion  23  will be moved in the direction of the longitudinal axis  15  and the second and (if appropriate) the third movable portions  25 ,  27  will be rotated around the longitudinal axis  15  from a closed position to an open position and vice versa. The movements allow that the blades  11  can pass through the slots  34  of the first movable portion  23  during their deployment/retraction because the first slot covers  36  of the second movable portion  25  are hidden inside the first movable portion  23  (see  FIG. 3 a   ). 
         [0029]    Within the meaning of this invention, a closed position of the first, second and third movable portions  23 ,  25 ,  27  shall be understood as the rest position for each of the movable portions, and an open position as the position reached after activating the driving means of each of the movable portions. 
         [0030]    In a deployment operation, the spinner  21  will change from a closed position with the blades  11  retracted inside the spinner  21  (see  FIGS. 1   a,    1   b ) to an open position (see  FIGS. 3   a,    3   b ) and, finally, to a closed position with the blades  11  deployed (see  FIGS. 4   a,    4   b ). 
         [0031]    The extension of the translational movement of the first movable portion  23  can be easily appreciated comparing the position of the guiding means  53 ,  55  in the closed position of the first movable portion (see  FIGS. 1 b  and 4 b   ) and the open position (see  FIG. 3 b   ) of the first movable portion, as well as the separation between the movable supporting frame  51  of the first movable portion  23  and the rotatable supporting frame  71  of the second movable portion  25  in a closed and an open position. 
         [0032]    Similarly, in a retracting operation, the spinner  21  will pass from a closed position with the blades  11  deployed to an open position and, finally, to a closed position with the blades  11  retracted inside the spinner  21 . In that case, the third movable portion  27  only shall be moved from its open position to its closed position at the end of the operation. 
         [0033]    An advantage of the invention is that allows to keep the blades  11  retracted inside the spinner  21  when they are not needed minimizing the drag and to deploy them when required, keeping aero or hydrodynamic properties as clean as possible. 
         [0034]    The invention also allows retracting blades when not required for self-powered gliders in flight, as well as in the case of taking-off with their own means. 
         [0035]    Another advantage is that the invention is applicable to pusher or puller type propeller devices. 
         [0036]    Although the present invention has been described in connection with various embodiments, it will be appreciated from the specification that various combinations of elements, variations or improvements therein may be made, and are within the scope of the invention as defined by the appended claims. 
         [0037]    While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.