Abstract:
A thruster assembly that in addition to propulsion provides water flow to/from compartments and systems on board a vessel. In a first position, the thruster assembly provides propulsion/steering. Pivoted to a second position, operation of the thruster in a first direction draws a flow into the vessel and in a second direction draws a flow out of the vessel. The flows may be conveyed to/from compartments/systems on board the vessel via conduits in communication with a chamber having an opening through which the thruster drives the flows. The flows may be used to submerge/surface the vessel, or to provide systems cooling or serve other functions. Pivoted to a third position the thruster assembly is retracted and enclosed within the chamber to form a hydrodynamically clean exterior.

Description:
RELATED CASES 
       [0001]    This application claims the benefit of Provisional Patent Application Ser. No. 62/231,163 filed Jun. 25, 2015. 
     
    
     BACKGROUND 
       [0002]    a. Field of the Invention 
         [0003]    The present invention relates generally to thrusters that provide motive power for watercraft, and, more particularly, to a thruster assembly that performs both propulsion and ballasting/dewatering functions onboard a vessel. 
         [0004]    b. Related Art 
         [0005]    Thrusters, as relate to waterborne vessels, are propulsive devices that are generally employed to propel and/or maneuver the vessel. As compared with shaft drives and other forms of propulsion that employ a remote power plant, thruster units commonly include an electric or hydraulic motor mounted in close association with the propeller itself in a submerged location, with electrical power or hydraulic pressure being supplied to the motor from a remote location within the hull. The propeller is frequently enclosed within a circular shroud. The motor may be reversible, and in some instances the assembly is pivotable so as to change the direction of thrust, e.g., to provide a steering effect. 
         [0006]    Thruster units provide significant advantages in many applications, but like all propulsion systems they consume a degree of power. Power consumption is virtually always a concern in vessel design and operation, but it even more so in the case of watercraft and other vessels that are small in size and/or are intended to operate for long periods of time without refueling. Exemplary of this type of vessel are craft intended for autonomous operation such as for observation and surveillance purposes, for example. Such craft—referred to from time-to-time as unmanned autonomous vessels (UAVs)—frequently rely on wind, waves and/or sunlight as sources of energy to satisfy their power requirements in whole or in part. Typically, power requirements include not only propulsion, but steering and guidance systems, sensors onboard computing systems, and other electrical or mechanical loads as well. Moreover, some such vessels are designed for submersible operation, which necessitates pumping equipment to ballast and deballast in order to submerge and surface the craft. The low energy density of environmental sources (wind, solar, wave) means that comparatively small amounts of power can be obtained, with the result that the power budget is generally very tight. A related factor is that any added weight requires more power to propel, thus increasing energy consumption. 
         [0007]    Much weight is the result of multiple components required to perform the above and additional functions. Furthermore, complexity and multiple components tend to both increase cost and reduce reliability, the latter again being a particularly significant consideration in the context of UAVs that must operate for extended periods with little or no human intervention. Weight and complexity also negatively impact the ability to transport, launch/retrieve and handle the craft. For example, many UAVs must be transported to distant operating areas (e.g., for military operations, ocean surveying, meteorological observations, and so on), often onboard an aircraft where weight and space are at a premium. Furthermore, after arriving at the operating area the craft must frequently be handled and launched from/recovered to a ship or other mother vessel, where excess weight can be a significant detriment. Still further, excess weight can compromise the vessel&#39;s maneuverability and responsiveness during operation. 
         [0008]    Accordingly, there exists a need for an apparatus that enables a waterborn vessel to employ a thruster for propulsion while taking advantage of the thruster for other functions, so as to consolidate systems and reduce overall complexity and weight of the vessel. Furthermore, there exists a need for such an apparatus that can be economically constructed and that is robust and able to perform reliably without excessive maintenance. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention addresses the problems cited above, and provides a thruster assembly having multiple functions, including the functions of providing propulsion for a vessel and of supplying and withdrawing flows of water to a on board the vessel. 
         [0010]    In a broad aspect, the invention provides an assembly comprising: (a) a thruster that generates a flow of water generally along an axis of the thruster; (b) a passage into the vessel, the passage having an opening generally at an exterior of the vessel; and (c) a mechanism that pivots the thruster between a first position in which the axis of the thruster is directed to produce a flow that provides propulsion to the vessel, and a second position in which the axis of the thruster is directed into the end opening of the passage to produce a flow that enters or exits the vessel. 
         [0011]    The passage into the vessel may comprise a chamber having the opening of the passage formed therein. The passage may further comprise at least one conduit extending from the chamber to an interior of the vessel. The at least one conduit may comprise an input conduit through which water flows from the chamber to on board the vessel in response to operation of the thruster in a first direction. The at least one conduit may comprise an outlet conduit through which water is withdrawn from the vessel in response to operation of the thruster in an opposite direction. The at least one conduit may comprise a first, inlet conduit in fluid communication with the chamber, and a second, outlet conduit in a fluid communication with the chamber. The conduits may comprise check valves that prevent backflow of water therethrough. 
         [0012]    The opening of the conduit may be located generally at a side of the vessel, with the chamber extending into an interior of the vessel. The side of the vessel at which the opening is located may be a bottom side of the vessel. The mechanism that pivots the thruster may comprise a mechanism that pivots the thruster from a first position in which the axis of the thruster extends generally parallel to an axis of the vessel, to a second position in which the axis of the thruster extends generally perpendicular to the axis of the vessel so as to be directed into the opening of the chamber. The pivot mechanism may be operable to pivot the thruster to a third position in which the thruster is received in an interior of the chamber in a position inverted from the propulsion position. 
         [0013]    The mechanism that pivots the thruster may comprise at least one pivot connection located proximate the external opening, about which the thruster is pivoted between its positions. The thruster may comprise a plate that is mounted to the thruster that closes off the exterior opening in response to the thruster being pivoted to the propulsion position, and that pivots upwardly together with an end of the thruster in response to the thruster being pivoted to the secondary position so as to permit the end of the thruster to enter the exterior opening. The closure plate may comprise an outer edge that conforms closely to an edge of the exterior opening when the thruster is in the drive position. 
         [0014]    The mechanism that pivots the thruster between the primary and secondary positions may comprise a pinion gear that is mounted to the thruster, a drive gear that is in engagement with the pinion gear, and a mechanism that rotates the drive gear so that in response the pinion gear rotates in an opposite direction so as to pivot the thruster. The drive gear may comprise a quadrant gear. The mechanism that rotates the drive gear may comprise a linear actuator, and a linkage connecting an end of the linear actuator to the drive gear at a location spaced from an axis of the drive gear. The linear actuator may comprise a hydraulic cylinder, and the linkage may comprise a link rod having a first end mounted to the end of the hydraulic cylinder and a second end mounted to the drive gear. The hydraulic cylinder may comprise a second end that is mounted to the chamber via a swing arm that enables the linear actuator to pivot as the actuator is extended and retracted. The swing arm may comprise a first end that is pivotably mounted to the second end of the hydraulic cylinder, and a second end that is pivotably mounted to the chamber. The second end of the swing arm may be pivotably mounted to the pivot of the drive gear. 
         [0015]    The assembly may further comprise a base that supports the pivot mechanism, chamber and thruster, and that is mountable in a cooperating opening in the vessel. 
         [0016]    The conduits may comprise conduits leading into and out of a hull space of the vessel or a compartment of the vessel. The flows of water through the conduits may serve the functions of flooding and dewatering to submerge and surface the vessel or to ballast the vessel, or may serve other functions. 
         [0017]    These and other features and advantages of the present invention will be more fully appreciated from a reading of the following detailed description with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a perspective view, partially in phantom, of a multifunction thruster assembly in accordance with the present invention; 
           [0019]      FIG. 2  is a front elevational view of the multifunction thruster assembly of  FIG. 1 ; 
           [0020]      FIG. 3  is a rear elevational view of the multifunction thruster assembly of  FIG. 1 ; 
           [0021]      FIG. 4  is a side elevational view of a submersible vessel having the multifunction thruster assembly of  FIGS. 1-3  mounted therein, showing the thruster assembly deployed below the hull of the vessel to operate in a propulsion mode; 
           [0022]      FIGS. 5A-5B  are side elevational and bottom plan views of the multifunction thruster assembly of  FIGS. 1-3 , in the deployed position shown in  FIG. 4 ; 
           [0023]      FIG. 6  is an enlarged elevational view of the multifunction thruster assembly of  FIGS. 1-3  in the deployed position shown in  FIG. 5A , partially cutaway to show the operating mechanism that pivots the thruster between operating and stowed positions; 
           [0024]      FIG. 7  is a side elevational view of the vessel and thruster assembly of  FIG. 4 , showing the thruster assembly pivoted to a second operational position for flooding/dewatering an interior compartment of the hull to submerge or surface the vessel; 
           [0025]      FIGS. 8A-8B  are side elevational and bottom plan views of the thruster assembly of  FIGS. 1-3  in the second deployed position of  FIG. 7 ; 
           [0026]      FIG. 9  is an elevational view of the thruster assembly of  FIGS. 1-3  in the position of  FIG. 8A , partially cutaway to show the position of the pivot mechanism of the assembly in greater detail; 
           [0027]      FIG. 10  is a side elevational view of the autonomous vessel and thruster assembly of  FIG. 4 , showing the thruster assembly pivoted to a stowed position in which the thruster assembly is passive, such as when operating on wind propulsion or during transportation/storage of the vessel, for example; and 
           [0028]      FIG. 11  is an enlarged side elevational view of the multifunction thruster assembly of  FIGS. 1-3 , in the position of  FIG. 10 , partially cutaway to show the position of the pivot mechanism when the assembly is in the stowed configuration. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]      FIG. 1  shows a multifunction thruster assembly  10  in accordance with the present invention. Principal subassemblies of the system include a thruster assembly  12  and a flow directing assembly  14 . As will be described in greater detail below, the thruster assembly includes a motor-driven thruster that generates a flow of water, while the flow directing system in turn positions the thruster and directs the flow to perform multiple tasks, namely, propulsion and ballasting of the vessel in the illustrated embodiment. It will be understood that, depending on application, additional secondary functions may be performed in addition to ballasting of the vessel, such as systems cooling or washdown functions, for example. 
         [0030]    Referring again to  FIG. 1  and also  FIGS. 2-3 , it can be seen that the thruster assembly  12  includes a motor section  20  having a drive motor, which may be an electric motor driven by batteries in the associated vessel, or which may be of a hydraulic, mechanical or other type in some instances. The motor section drives a propeller section  22  having a propeller (not shown) housed within a shroud  24 , the latter serving to contain and direct the water flow that is produced by operation of the propeller. As can better be seen in  FIGS. 2-3 , the forward end of the thruster is supported by a short tubular shaft  26  from a somewhat door-shaped pivotable panel  28 , the tubular shaft also housing wiring by which power and control inputs are supplied to the motor. The upper edge of the propeller shroud  22  is in turn mounted to panel  28  to support the rearward end of the assembly, so that the motor and propeller sections of the thruster are rigidly joined to and supported by the pivotable panel. An example thruster suitable for use in the assembly is the SeaBotix™ BTD150, available from SeaBotix Inc., 1425 Russ Blvd, San Diego, Calif., 92101. 
         [0031]    As can be seen with further reference to  FIGS. 2-3  and also  FIGS. 5A-5B and 6 , panel  28  is received with a generally correspondingly shaped edge  30  of an opening  32  (see  FIG. 8A ) formed in a belly plate  34  that is mounted to the hull of the vessel, the belly plate preferably being contoured to form a faired surface with the surrounding area of the hull. Panel  28  is supported within opening  32  on horizontal axis pivots  34 ,  36 , that lie more-or-less within the general plane of the belly plate. As can also be seen in  FIG. 5B , the transverse axis of the pivots  34 ,  36  is located generally proximate a lengthwise midpoint of the panel  28 , so that when pivoted in a first direction a front end of the panel swings upwardly above the level of the belly plate and the rearward end pivots downwardly below the belly plate, and vice versa, together with the components of the thruster unit that are mounted on the panel. 
         [0032]    As can be seen with further reference to  FIG. 6 , a first gear  40  is mounted to the outer end of the shaft  42  of pivot connection  34 , so that in response to rotation of the gear the panel and thruster unit tilt in one or the other in the manner described above, the downwardly-extending portion of the gear being housed within a depending blister  44  on the corresponding side of the belly plate. The upper portion of gear  40  is in turn engaged by a second, larger gear, in the form of a quadrant gear  46 . The quadrant gear is supported on a horizontal stub axle  48  and engages the first gear  40 , so that rotation of the quadrant gear in a first direction rotates the smaller pinion gear  40  at a greater rate in the opposite direction. 
         [0033]    Rotation of the gears  36 ,  40 , thus pivoting plate  28  and the thruster  12 , is accomplished by operation of a linear actuator, in the form of a hydraulic cylinder  50 , that is connected to upper quadrant gear  46  by a link rod  52 . As can be seen in  FIGS. 1 and 6 , a forward end of the link rod is mounted to the quadrant gear at a first horizontal axis pivot connection  54 , while the other end of the rod is mounted to the rearward end of the hydraulic cylinder by second horizontal pivot connection  58 . The forward end  58  of the hydraulic cylinder is in turn mounted to a pivot connection  60  on the rearward end of a swing arm  62 , the forward end of the latter being pivotally connected to the stub axle  48  inboard of quadrant gear  46 . Therefore, extension of the hydraulic cylinder, in response to pressure supplied by hydraulic connection  64 , draws the link rod  52  rearwardly, pivoting the quadrant gear in a clockwise direction as seen in  FIG. 6 , thus rotating gear  40  so as to pivot the door plate and thruster unit in the opposite (counterclockwise) direction; retraction of the cylinder in turn forces the link rod in a forward direction and reverses operation of the gear train and pivoting motion of the thruster assembly. The pivot joints  54 ,  58 ,  60  and  48  allow the angular geometry of the assembly to adjust as the linear actuator extends and retracts, the pivot connection  54  on the quadrant gear having an inboard end that rides in an arcuate guide slot  66  so as to constrain the movement to the desire range of motion. A resilient bellows-type gaiter  68  installed about the shaft of the hydraulic cylinder  50  protects the shaft and cylinder from exposure to salt water during immersion. It will also be understood that some embodiments may employ other forms of linear actuators, such as pneumatic cylinders, gear racks, ball screws and linear motors, for example. 
         [0034]    As noted above, the plate  28  from which the thruster is suspended is located within opening  32  that leads upwardly into the assembly. As can be seen with further reference to  FIG. 8A  and also  FIGS. 1-3 , the opening  32  is formed in the bottom of a domed chamber  70 , that extends upwardly above the belly plate  34  into the interior of the vessel. Discharge and intake lines  72 ,  74  communicate with chamber  70  and extend rearwardly therefrom, the intake line being set somewhat lower than the discharge line so as to be positioned more closely adjacent the bottom of the hull. In addition, a boss  76  on one side of the chamber wall supports the horizontal stub axle  48  of the pivot assembly, with guide channel  66  being formed in the side of the chamber somewhat below the stub axle. 
         [0035]    The discharge and intake lines  72 ,  74  include end openings  76 ,  78  that communicate with an interior volume or compartment of the vessel. The openings may be located directly within the compartment or volume into which water is discharged and from which it is drawn, or hoses, manifolds or other conduits may be connected to the openings so as to lead the flow to/from remote locations. Check valves  80 ,  82  are installed in lines  72 ,  74  so as to prevent backflow. Consequently, water may be supplied to an interior volume of the vessel from chamber  70  through line  72 , and withdrawn back out via line  74 . In the illustrated embodiment, the intake pipe and lower portion of the chamber are set within a tray-shaped coaming  84  extending upwardly from belly panel  34  that fits within a cooperating hull opening so as to locate the assembly in the bottom of the vessel and that also imparts strength and structural rigidity to the assembly, with drain parts  86  being formed in the coaming above the belly plate to permit water to pass therethrough during deballasting. 
         [0036]    Mounted together on the belly plate, the assembly forms a compact, structurally self-contained unit that can be mounted in a corresponding opening in the hull of the vessel and that can be conveniently removed for servicing. In some embodiments, however, some the components may be mounted to the hull or other structure of the vessel while others may be mounted to the assembly base, or all of the components may be mounted to or built into the structure o the vessel itself. 
         [0037]    Operation of the multifunction thruster assembly is illustrated in  FIGS. 4-11 , with respect to an exemplary submersible craft  90  that is shown in simplified form, having a hull  92  with an interior volume or compartment  94 . 
         [0038]    Firstly,  FIGS. 4-6  show the thruster assembly positioned to function in a propulsion mode, providing thrust to move/maneuver the vessel. To bring the assembly to the propulsion configuration, the controls are actuated to extend hydraulic cylinder  50 , in the direction indicated by arrow  100  in  FIGS. 5A and 6 . As noted above, this in turn draws link rod  52  rearwardly, causing the quadrant gear  46  to rotate about axle  48  in the direction indicated by arrow  102  in  FIG. 6 . In so doing, the quadrant gear rotates the pinion gear  40  in the opposite direction, as indicated by arrow  104 , bringing the motor and propeller  20 ,  22  of the thruster unit  12  to a horizontal axis orientation. Simultaneously, panel  28  comes to a horizontal orientation, closing off the opening  32  at the bottom of chamber  70  and fitting closely within the edge  30  of the opening to form a smooth, substantially continuous contour. Thus positioned, forward and reverse operation of the thruster unit  12  generates forward and reverse propulsive thrust, in the direction indicated by arrows  106 ,  108  in  FIG. 4 . It will be understood that some embodiments may employ different forms of mechanisms to pivot the thruster assembly between positions, such as crank, chain-and-sprocket, pulley and motor mechanisms, for example. 
         [0039]      FIGS. 7-9 , in turn, show the vessel  90  with the thruster assembly configured to operate in a ballasting/dewatering mode. 
         [0040]    In order to shift the thruster assembly to the ballasting position, hydraulic cylinder  50  is retracted in the direction indicated by arrow  110  in  FIGS. 8A-9 , driving link rod  52  forward towards chamber  70  so as to rotate quadrant gear  46  in a counterclockwise direction (viewed from the right side), as indicated by arrow  112  in  FIG. 9 . This in turn rotates pinion gear  40  in a clockwise direction together with closure panel  28 , in the direction indicated by arrows  114  and  116 . As the front of the closure plate tilts downwardly, the rearward end tilts upwardly into chamber  70 , until the thruster unit  12  is aligned vertically, with the shrouded propeller section  22  of the thruster being received in the rearward portion of the chamber opening  32  aft of the closure plate pivot connections  34 ,  36 , as seen in the bottom view of  FIG. 8B . In this position, operation of the thruster in its forward direction draws water upwardly from the bottom of the craft and force it into chamber  70 , as indicated by arrow  118  in  FIG. 7 , from which the water is then discharged into the interior volume of the vessel in a direction indicated by arrow  120 . Dewatering is accomplished by operating the thruster in the reverse direction, as indicated by arrow  122  in  FIG. 7 , drawing the water from the interior volume into intake line  74  in the direction indicated by arrow  124 . The flooding and dewatering of the interior volume, which as noted above may be a dedicated compartment or simply an interior of the hull, may be performed in order to ballast/submerge the vessel and the deballast/surface the vessel, for example, or for other purposes. Moreover, as was also noted above, the flow of the water to/from the chamber may be utilized for other purposes, such as equipment cooling or topside washdown/decontamination, for example. Still further, it will be understood that only inflow or outflow functions and not both may be present in some embodiments, and similarly that only a single input/output conduit may be included, rather than multiple conduits as shown. 
         [0041]      FIGS. 10-11  show the thruster assembly in a stowed configuration, for operation of the craft by wind power using sails (not shown) or for transportation/storage of the vessel  90 , for example. 
         [0042]    To shift the thruster assembly to the stowed position, the hydraulic cylinder  50  is further retracted, in the direction indicated by arrow  130  in  FIG. 11 , driving link rod  52  further forward and rotating quadrant gear  46  in the direction indicated by arrow  132 . Pinion gear  40  counter rotates in the direction indicated by arrow  134 , further from the position shown in  FIG. 9 , pivoting the closure panel  28  until it is inverted from the original propulsion position shown in  FIGS. 4-6  and the motor and propeller sections of the thruster unit are received and enclosed within the interior of chamber  70 . The exposed surface  136  of the now inverted closure panel is contoured to correspond to the adjoining surface of belly plate  34  and fits closely within the edge  30  of the chamber opening, thus forming a smooth, substantially continuous low-drag surface with minimal protrusions when the assembly is in the stowed configuration. 
         [0043]    It will be understood that the scope of the appended claims should not be limited by particular embodiments set forth herein, but should be construed in a manner consistent with the specification as a whole.