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CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application 61/426,393, filed Dec. 22, 2010, the entire content of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to methods and apparatus for emptying sewage or other storage tanks of recreational vehicles and other mobile units having sewage or other storage tanks. 
     BACKGROUND 
     Many recreational vehicles, such as mobile homes, include toilets having on-board sewage storage. In order to drain sewage from sewage storage tanks of the prior art, an operator performs a series of steps. First, the operator removes a sewage hose from its storage position and manually attaches one end of the sewage hose to a drain valve of the recreational vehicle. The sewage hose is then manually extended toward the sewage disposal unit at the park or campsite, for example, and the sewage hose is manually coupled to the inlet of the sewage disposal unit. The operator then opens the valve of the recreational vehicle tank in order for the sewage to drain into the sewage disposal unit inlet. Once all of the sewage has drained, the operator removes the dirty sewage hose from the sewage disposal unit inlet, removes the hose from the recreational vehicle drain valve and closes the drain valve. The operator then manually returns the sewage hose to its storage position. 
     These steps are quite onerous and often result in the operator coming into contact with the sewage. 
     SUMMARY 
     In an aspect there is provided an apparatus for moving a sewage conduit of a vehicle to a sewage disposal unit, the apparatus including: a base coupled to the vehicle; a link arm comprising a first end and a second end, the first end being hinged to the base; an upper arm assembly comprising an upper arm and an extendible arm, a first end of the upper arm being hinged to the second end of the link arm and a first end of the extendible arm being axially movable relative to the upper arm to move the upper arm assembly between a retracted position and an extended position, a second end of the extendible arm for coupling to an outlet of the sewage conduit of the vehicle; wherein the base is rotatable for directing the second end of the extendible arm toward the sewage disposal unit and the link arm and upper arm assembly are movable to extend the second end of the extendible arm to the sewage disposal unit. 
     In another aspect there is provided an apparatus for emptying a sewage storage tank of a vehicle into a sewage disposal unit, the apparatus including: an extendible member coupled to the vehicle, the extendible member comprising a first end pivotally coupled to the vehicle and a second end for coupling to an outlet of a sewage conduit of the vehicle, the extendible member being movable between a retracted position and an extended position; wherein the extendible member is pivotable and extendible for moving the outlet of the sewage conduit into communication with the inlet of the sewage disposal unit prior to opening the valve of the sewage storage tank. 
     There is also provided herein a self-supporting chain including: a roller chain including links coupled to one another, the roller chain being limited to bending in a single plane; stops coupled to one side of the roller chain between adjacent ends of the links; wherein the rolling chain is movable from a retracted position to an extended position and the stops limit bending of the roller chain beyond a generally linear position. 
    
    
     
       DRAWINGS 
       The following figures set forth embodiments in which like reference numerals denote like parts. Embodiments are illustrated by way of example and not by way of limitation in the accompanying figures. 
         FIG. 1  is a side view of an example recreational vehicle including an apparatus for emptying sewage according to an embodiment; 
         FIG. 2  is an enlarged view of a portion of  FIG. 1 ; 
         FIG. 3  is a top view of the example recreational vehicle of  FIG. 1 ; 
         FIG. 4  is an enlarged view of a portion of  FIG. 3 ; 
         FIG. 5  is a rear view of the example recreational vehicle of  FIG. 1 ; 
         FIG. 6  is an enlarged view of a portion of  FIG. 5 ; 
         FIG. 7  is a rear view of another example recreational vehicle including an apparatus for emptying sewage according another embodiment in which the apparatus in an extended position; 
         FIG. 8  is an enlarged view of a self-supporting chain of the apparatus for emptying sewage of  FIG. 7 ; and 
         FIG. 9  is a rear view of the example recreational vehicle of  FIG. 7  in which the apparatus for emptying sewage is in a retracted position. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , an apparatus  12  for moving a sewage conduit of a vehicle toward a sewage disposal unit (not shown) is coupled to a recreational vehicle  10 , which is shown by way of example. The apparatus  12  may be installed on any vehicle having an on-board sewage storage tank including: recreational vehicles, trailers or boats, for example. 
     The apparatus  12  is located in a recess  14  that is provided near a sewage storage tank (not shown) of the vehicle  10 . The recess  14  is sized to include an outlet  16  of the sewage storage tank, the apparatus  12  and a sewage conduit  18 , which is coupled to the outlet  16 . A cover (not shown) is removable to allow the operator to access the recess  14 . The cover may be a hinged door that is openable to allow the operator to access the recess  14 . 
     The sewage conduit  18  is generally a hose that is coupled to the outlet  16  of the sewage storage tank. The sewage conduit  18  is collapsible and is stored within the recess  14  when not in use. In the embodiment of  FIGS. 1 and 2 , the sewage conduit  18  is a collapsible corrugated pipe having an outlet  20 . The sewage conduit may alternatively be a telescopic pipe or another retractable or collapsible pipe, for example. 
     Referring also to  FIGS. 3 and 4 , the apparatus  12  includes a base  22 , a link arm  24  and an upper arm assembly  26 , which includes an upper arm  28  and an extendible arm  30 . The apparatus  12  further includes a motor driven hydraulic pump and valve assembly  32  and a control panel  34  for controlling movement of the link arm  24  and upper arm assembly  26 . 
     The base  22  includes a fixed portion  36  and a rotatable portion  38 . The fixed portion  36  is coupled to a lower surface  40  of the recess  14  and the rotatable portion  38  rotates relative thereto. 
     A first end  42  of the link arm  24  is hinged to the base  22  and a first end  46  of the upper arm  28  is hinged to a second end  44  of the link arm  24 . The extendible arm  30  of the upper arm assembly  26  is movable relative to the upper arm  28  along an axis of the upper arm  28 . Movement of the extendible arm  30  may be powered by hydraulics (water or oil), electric motor or movement of the extendible arm may be manually achieved using a cable system, for example. In one embodiment, the movement of the extendible arm  30  may be achieved manually by including a handle (not shown) on the extendible arm  30  so that the operator may manually move the sewage conduit  18 . 
     A second end  48  of the extendible arm  30  includes a clamp  52  that is continuously coupled to the outlet  20  of the sewage conduit  18 . The clamp  52  is generally an elbow-shaped fitting that redirects sewage exiting the sewage conduit  18  into the sewage disposal unit. Although the sewage conduit  18  is continuously coupled to the outlet of the sewage storage tank at one end and the clamp  52  at the opposite end, it will be appreciated by a person skilled in the art that the sewage conduit may be de-coupled to allow for cleaning, replacement or repair, for example. 
     The apparatus  12  is rotatable to swing the link arm  24  and upper arm assembly  26  in the direction indicated by arrow  54  of  FIG. 4 . The maximum range of rotation of the rotatable portion  38  is at least 180 degrees, however, the range may be reduced based on how far the base  22  is located into the recess  14 . When extended, the link arm  24  and the upper arm assembly  26  cover a distance of approximately 20 ft from the base  22 . In other embodiments this distance may be increased or reduced by adjusting the length of one or more of the link arm  24 , the upper arm  28  and the extendible arm  30 . 
     A first sensor  56  is coupled to the second end  48  of the extendible arm  30 . The first sensor  56  is for communicating with a second sensor (not shown). The second sensor is stored in the vehicle  10  and is movable by the operator to a location adjacent the inlet of the sewage disposal unit. In general, the first sensor  56  is a receiver and a transmitter and the second sensor is at least a transmitter. The first sensor  56  receives location information from the second sensor and sends its own location information and the location information of the second sensor to the control panel  34 , which controls movement of the apparatus  12 . In one embodiment, both sensors send their respective location information to the control panel  34 . In another embodiment, both sensors are provided with both receiving and transmitting capabilities. 
     The control panel  34  is generally a computer that is in communication with the motor driven hydraulic pump and valve assembly  32 , which forces fluid through hydraulic lines  64  that actuate first and second hydraulic cylinders,  58  and  60 . The hydraulic cylinders  58  and  60  are coupled between the base  22  and the link arm  24  and the link arm  24  and the upper arm  28 , respectively. The control panel  34  further controls opening and closing of the valve (not shown) at the outlet of the sewage control tank. Alternatively, opening and closing of the valve may be performed manually. 
     Movement of the apparatus  12  may be controlled automatically based on feedback from the first sensor  56  and second sensor or may be controlled manually by using a joystick  62 , which is coupled to the control panel  34 . 
     In operation, in order to empty the on-board sewage storage tank, the operator parks the vehicle  10  near a sewage disposal unit at a campsite or recreational vehicle park, for example, and removes the cover to expose the sewage conduit  18  and the apparatus  12 . Using the control panel  34 , the operator then initiates movement of the apparatus  12  to move the outlet  20  of the sewage conduit  18  into communication with the sewage disposal unit, as shown in  FIGS. 5 and 6 . Once the outlet  20  is positioned so that sewage exiting the sewage conduit  18  will be deposited into the sewage disposal unit, the operator then opens the valve at the outlet of the sewage storage tank to allow sewage to empty from the on-board sewage storage tank. Once sewage disposal is complete, the operator operates the control panel  34  to close the valve and retract the apparatus  12  into the recess  14 . 
     In another embodiment, the base  22 , link arm  24  and upper arm assembly  26  are manually operable to move the outlet  20  of the sewage conduit  18  into communication with the sewage disposal unit. In this embodiment, the motor, control panel and hydraulic cylinders are omitted and a handle is coupled to the extendible arm  30  adjacent the second end  48 . In operation, the operator would manually locate the outlet  20  of the sewage conduit  18  using the handle and manually open the valve at the outlet of the sewage storage tank using a lever or other externally accessible valve-opening mechanism. Once sewage disposal has completed, the operator would manually close the valve and stow the sewage conduit and apparatus. 
     In yet another embodiment, rather than being hydraulically powered, the apparatus  12  is electro-mechanically powered. In this embodiment, the hydraulic cylinders are replaced by electric servo motors. 
     In another embodiment, a video camera is provided in communication with the control panel  34 . In this embodiment, the video camera is mounted to the recreational vehicle  10  and is able to view the inlet of the sewage disposal unit. An object may be placed beside the inlet of the sewage disposal unit and the camera provided with software having object recognition capability, which identifies the object and provides location information to the control panel  34 . The control panel  34  would then direct the apparatus  12  to the inlet of the sewage disposal unit. The video camera may be used with hydraulic powered apparatus  12  or an electro-mechanically powered apparatus  12 . 
     In still another embodiment, the software of the video camera is capable of identifying at least one feature of the inlet of the sewage disposal unit and providing location information to the control panel  34 . 
     Referring now to  FIG. 7 , according to another embodiment, an apparatus  112  for moving a sewage conduit  118  toward a sewage disposal unit (not shown) is coupled to a recreational vehicle  110 . Similar to the apparatus  12  of  FIGS. 1 to 6 , the apparatus  112  may be installed on any vehicle having an on-board sewage storage tank including: recreational vehicles, trailers or boats, for example. 
     The apparatus  112  is located in a recess  114  of the vehicle  110 , near a sewage storage tank  66 . The recess  114  is sized to include an outlet  116  of the sewage storage tank  66 , the apparatus  112  and the sewage conduit  118 . A cover (not shown) is removable to allow the operator to access the recess  114 . The cover may be a hinged door that is openable to allow the operator to access the recess  114 . In the recreational vehicle  110  of  FIG. 7 , the recess  114  is located on the back of the recreational vehicle  110 , however, the recess  114  may alternatively be located on a side or other location near the sewage storage tank  66 . 
     The sewage conduit  118  is generally a hose that is coupled, at a first end, to the outlet  116  of the sewage storage tank  66 . The sewage conduit  118  is wound around a sewage conduit reel  68  that is mounted on a platform  70  and is rotatable to extend and retract the sewage conduit  118 . The sewage conduit  118  is stored in a retracted position, as shown in  FIG. 9 , when not in use, and movable toward an extended position, which is shown in  FIG. 7 , for sewage disposal. A second end of the sewage conduit  118  is coupled to a pipe elbow  75 , which is inserted into an inlet of a sewage disposal unit during sewage disposal. 
     The sewage conduit  118  is movable between the retracted position and the extended position by a self-supporting chain  72 . The self-supporting chain  72  is wound around a chain reel  74  when retracted and is movable between the retracted and extended positions by a chain motor  84 . The motor  84  includes a rotatable gear  86  having teeth  88  for engaging the self-supporting chain  72 . The chain reel  74  is mounted on the platform  70  adjacent to the sewage conduit reel  68 . A clamp  76  is located at a second end of the self-supporting chain  72  to couple the self-supporting chain  72  to the pipe elbow  72 . Because the second end of the self-supporting chain  72  is coupled to the second end of the sewage conduit  118 , the sewage conduit  118  extends when the self-supporting chain  72  extends. Similarly, the sewage conduit  118  retracts when the self-supporting chain  72  retracts. 
     Referring also to  FIG. 8 , the self-supporting chain  72  includes a plurality of stops  78  that are coupled to a lower side of a roller chain  80  including a plurality of links  82 . The roller chain  80  may be any industrial chain that is limited to bending in a single plane to wind and unwind the roller chain  80 . In the example of  FIG. 8 , the stops  78  are plates that are located on an underside of the self-supporting chain  72  when the apparatus  112  is installed in the vehicle  110 . The plates are coupled between adjacent ends of the links  82  and support the links  82  when the self-supporting chain  72  is extended in order to maintain the self-supporting chain  72  in a generally linear position. The plates restrict rotation of the roller chain  80  in one direction only, therefore, the self-supporting chain  72  may be wound around the chain reel  74  when the self-supporting chain  72  is in the retracted position. 
     It will be appreciated by a person skilled in the art that the stops  78  are not limited to being plates, the stops  78  may be any component capable of limiting movement of adjacent links  82  relative to one another. Further, one or both of the sewage conduit reel  68  and the chain reel  74  may be spring loaded to automatically retract the sewage conduit  118  and the self-supporting chain  72 . 
     The apparatus  112  includes a base  122  that is rotatably coupled to the recreational vehicle  110 . The base  122  includes a rotation unit  90  having a chain  98  that is movable by a worm gear and sprocket arrangement (not shown) that is driven by a first motor  92 . A tilting unit  94  is coupled between the base  122  and a platform  70 . A worm gear  100 , which is driven by a second motor  96 , engages a mating component  102  that extends from an underside  104  of the platform  70  to tilt the platform  70  about a tilting axis  95 . It will be appreciated by a person skilled in the art that the base  122  and platform  70  may alternatively be hydraulically, electrically or manually driven. 
     Together, the base  122  and the platform  70  facilitate pivoting of the platform  70  relative to the vehicle  110 . The amount that the base  122  is able to rotate relative to the vehicle  110  may be dependent on the location of the base  122  within the recess  114  as well as a starting position of the base  122 . In one example, the base  122  is rotatable  180  degrees. The amount that the tilting unit  94  is able to tilt may be dependent on the location of the base  122  within the recess  114 , the distance between the base  122  and the platform  70  and the length of the worm gear  100 , for example. In one example, the tilting unit  94  is able to tilt the platform  70  45 degrees. 
     Referring back to  FIG. 7 , a first sensor  156  is coupled to the second end of the self-supporting chain  72 . A second sensor  155  is for locating next to the sewage disposal unit during sewage disposal. The sensors operate in a similar manner as has been described with respect to the first and second sensors of the embodiment of  FIGS. 1 to 6 . The first sensor  156  and the second sensor  155  are coupled to sensor cables, which are wound on sensor cable spools  165 ,  167 , respectively, when not in use. The sensor cable spools  165 ,  167  may be spring loaded to automatically retract the cables following use. In one embodiment, the sensor cables are eliminated and the sensors  156 ,  155  communicate wirelessly. 
     The apparatus  112  further includes a control panel (not shown), which is generally a computer that is in communication with the first motor  92 , the second motor  96  and the chain motor  84 . Movement of the apparatus  112  may be controlled automatically based on feedback from the first sensor  56  and second sensor  160  or may be controlled manually by using a joystick (not shown) or other input device in communication with control panel. The control panel operates in a similar manner as has been described in relation to the embodiment of  FIGS. 1 to 6  and, therefore, will not be described further here. 
     In operation, in order to empty the on-board sewage storage tank  72 , the operator parks the vehicle  110  near a sewage disposal unit at a campsite or recreational vehicle park, for example, and removes the cover to expose the apparatus  112 . Using the control panel, the operator then initiates movement of the apparatus  112  to move an outlet of the pipe elbow  75  of the sewage conduit  118  into communication with the sewage disposal unit, as shown in  FIG. 7 . Movement of the apparatus  112  may include rotation by the rotation unit  90 , tilting by the tilting unit  94 , and extension of the self-supporting chain  72 . Once the outlet is positioned so that sewage exiting the sewage conduit  118  will be deposited into the sewage disposal unit, the operator then opens the valve at the outlet of the sewage storage tank  66  and turns on a sewage pump  105  to pump sewage from the on-board sewage storage tank  66  through the sewage conduit  118 . Once sewage disposal is complete, the operator operates the control panel to close the valve and stop the sewage pump and to retract the extendable arm into the recess  114 . 
     It will be appreciated by a person skilled in the art that pivoting of the apparatus  112  and extension and retraction of the sewage conduit  118  and sensor cables may be performed manually. 
     The embodiment of  FIGS. 7 and 9  is not limited to including a self-supporting chain  72 . As will be appreciated by a person skilled in the art, the apparatus  112  may include other types of extendible members. Any extendible member capable of positioning the outlet of the pipe elbow  75  relative to a sewage disposal unit may be used, such as an extendible arm similar to the extendible arm  30  described in relation to  FIGS. 1 to 6 , for example. 
     Although sewage disposal has been discussed, it will be appreciated by a person skilled in the art that the sewage conduit may also be used to dispose of grey water from a recreational vehicle, for example. When disposing of grey water, a grey water valve is opened to allow the grey water to flow into the sewage conduit. 
     An advantage of the embodiments described herein is that the operator does not contact the sewage conduit so that the sewage disposal process is sanitary and does not result in the operator coming into contact with sewage. 
     A further advantage of the embodiments described herein is that the recess provides space so that the sewage conduit may be continuously coupled to the outlet of the sewage storage tank. Re-connection of the sewage conduit to the outlet each time sewage is disposed of, is therefore avoided. 
     Specific embodiments have been shown and described herein. However, modifications and variations may occur to those skilled in the art. All such modifications and variations are believed to be within the scope and sphere of the present embodiments.

Summary:
An apparatus for emptying a sewage storage tank of a vehicle into a sewage disposal unit, the apparatus including: an extendible member coupled to the vehicle, the extendible member comprising a first end pivotally coupled to the vehicle and a second end for coupling to an outlet of a sewage conduit of the vehicle, the extendible member being movable between a retracted position and an extended position; and wherein the extendible member is pivotable and extendible for moving the outlet of the sewage conduit into communication with the inlet of the sewage disposal unit prior to opening the valve of the sewage storage tank.