Abstract:
An apparatus for moving an expandable room of a vehicle between a raised position and a lowered position is disclosed. The apparatus comprises at least one lift station attachable to the vehicle, an arm combined with the lift station, a rotatable member rotatably combining the at least one lift station and the arm, wherein the lift station rotates the arm between the raised position and the lowered position, and a support member fixed to the arm and engaging the expandable room, wherein the support member supports the expandable room.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Application 61/224,777 filed Jul. 10, 2009, which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This invention relates to movement of an expandable room in a recreational vehicle. 
     BACKGROUND 
     A variety of recreational vehicles are known and used that have a room or a room portion that may be moved from a retracted position while the vehicle is moving to an extended position when the vehicle is stationary to provide additional space. It is desirable to provide a mechanism to extend and retract the expandable room, and a mechanism that also provides support for the weight of the expandable room and reduces the complexity and cost of the mechanism. 
     SUMMARY 
     An apparatus for moving an expandable room of a vehicle between a raised position and a lowered position is disclosed. The apparatus comprises at least one lift station attachable to the vehicle, an arm combined with the lift station, a rotatable member rotatably combining the at least one lift station and the arm, wherein the lift station rotates the arm between the raised position and the lowered position, and a support member fixed to the arm and engaging the expandable room, wherein the support member supports the expandable room. In an embodiment the lift station includes a frame that is attachable to the vehicle. An actuator is used to move the expandable room between the raised position and the lowered position. A support member extends substantially a length of the expandable room and parallel with a longitudinal side of the vehicle. In an alternate embodiment, a second lift station is provided and the rotatable member extends between and beyond the two lifts stations. An end member combines the support member with the rotatable member near an end of the support member and the rotatable member. 
     In yet another embodiment, a method for moving an expandable room of a vehicle between a raised position and a lowered position is disclosed. The method comprises, providing substantially axial motion from an actuating member, converting the substantially axial motion from the actuating member to rotary motion of a support member, and using the rotary motion of the support member to linearly move the expandable room between the raised position and the lowered position. In another embodiment, a method is disclosed to provide support across the length of the expandable room and synchronize the raising and lowering of the expandable room. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of particular embodiments and their features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a side view of a recreational vehicle having an expandable room; 
         FIG. 2  is a rear view of the recreational vehicle with the expandable room in an extended position; 
         FIG. 2A  is a is a rear view of the recreational vehicle with the expandable room in a retracted position; 
         FIG. 3  is a perspective view of the expandable room in the extended and raised position; 
         FIG. 4  is a side view of the rack and pinion mechanism; 
         FIG. 5  is a front section view of an embodiment of the invention showing the rack and pinion mechanism; 
         FIG. 6  is a perspective view of the lift platform mechanism in the lowered position; 
         FIG. 7  is a perspective view of the lift platform mechanism in the raised position; 
         FIG. 8  is a side view of a lift station; 
         FIG. 9  is a schematic diagram of an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present application hereby incorporates by reference U.S. patent application Ser. No. 11,693,297 filed Mar. 29, 2007 to Hanser. 
       FIGS. 1 ,  2 ,  2   a , and  3  illustrate a recreational vehicle  50  with at least one expandable room  52  having a drive chain assembly to control the horizontal movement of the room  52  and a lift platform mechanism  100  to control the vertical movement of the room  52 . The preferred embodiment for the horizontal movement of the expandable room  52  is the drive chain assembly with rack and pinion mechanism disclosed in Hanser, however, any mechanism to control horizontal movement of an expandable room  52  is covered. The invention is described herein as being applicable to leveling an expandable room  52  that extends outwardly from a side wall of the recreational vehicle  50 , but the principles of the invention are applicable to the leveling of expandable and retractable movable structures in other applications as well. 
     The expandable room  52  has an upper horizontal frame member  10  and a lower horizontal frame member  12  that form a part of an interior side wall of the expandable room  52 . The upper surface of the frame members  12  defines the floor  12   a  of the expandable room  52  and the lower surface of the upper frame members  10  defines the ceiling  10   a . Each of the side walls formed by the upper and lower frame members  10  and  12  are connected by a vertical frame member  14 . 
     The frame member  14  comprises brackets  19  that attach to the room  52 . The outer ends of the upper and lower frame members  10  and  12  are connected by vertical frame members (not shown) that form the outer end wall  17  of the expandable room  52 . The side walls are interconnected by lateral support members (not shown) that form a box-like structure that defines the expandable room  52 . The expandable room  52  nests within the vehicle  50  between vertical supports  16  that form a part of the vehicle  50  side wall structure. 
     When the vehicle  50  is traveling over the road, the expandable room  52  is retracted, as illustrated in  FIG. 2A , with the outer end wall  17  of the expandable room  52  generally flush with the exterior wall of the recreational vehicle  50  that includes vertical support members  16 .  FIG. 2  illustrates the expandable room  52  structure in the extended position with the frame member  14  of the expandable room  52  positioned adjacent the vehicle support members  16 . 
     Referring to  FIGS. 3-5 , mounted in the vehicle vertical support  16  is a force assist member  18 , such as a main hydraulic cylinder  18 , having an operating rod  20  which is connected to a bracket  22  that is in turn connected to the end of a lower chain  24 . A rack-and-pinion mechanism  250  extends vertically inside the vertical support  16 . The rack-and-pinion mechanism  250  comprises an upper rack  27  and a lower rack  23  operatively combined by a gear  25 . The upper rack  27  is combined with the upper chain  28  and the lower rack  23  is combined with the lower chain  24 . 
     In an embodiment, the lower rack  23  is combined with the lower chain  24  by bracket  22 . The lower chain  24  is moved downward by the cylinder  18 , which moves the lower rack  23  causing the gear  25  to rotate. The rotation of the gear  25  causes the upper rack  27  to move in the opposite direction as the lower rack  23 . This forces the upper chain  28  to move outward from the recreational vehicle  50  at the same rate as the lower chain  24  is moving outward from the recreational vehicle  50 . Thus, the rack-and-pinion mechanism  250  provides simultaneous movement of both chains  24  and  28  when the operating rod  20  moves to either push or pull the chains  24  and  28 . This design allows a single acting driving force (i.e., main cylinder  18 ) to help synchronize the movement of these chains  24 ,  28  in opposite directions to each other. One benefit of this arrangement is that the upper chain  28  can be located near the top of the mechanism for attachment near the top of the room  52 , as seen in  FIG. 3 , such that the expandable room  50  is extended and retracted at its four corners. 
     The chains  24  and  28  are guided for vertical movement inside the vertical support  16 , and the chains  24  and  28  exit the vertical support  16  through a guide member  30  that turns the chains  24  and  28  from vertical to horizontal where the other ends of the chains  24 ,  28  are connected to the vertical frame members  14  near the interior end wall  15  of the expandable room  52 . Each of the drive chains  24  and  28  are comprised of consecutive links pivotally connected to each other and are of a type that allow the drive chains  24  and  28  to flex in one direction only thereby allowing the chain  24 ,  28  to be pushed from one end link to the other end link as well as being pulled. A chain of this type is well known to those skilled in the art and is more specifically described in U.S. Pat. No. 6,679,541, which is hereby incorporated by reference. Thus, as the operating rod  20  of hydraulic cylinder  18  travels vertically, chains  24  and  28  are pushed or pulled to move the expandable room  52  horizontally between a retracted position and an extended position. 
     Referring to  FIGS. 6-8 , in preferred embodiment of the lift platform mechanism  100  is shown in detail. The lift platform mechanism  100  is located underneath the flooring of the recreational vehicle  50 . After the expandable room  52  is extended the lift platform mechanism  100  lowers the expandable room  52  so that the floor  12   a  of the expandable room  52  is substantially flush with the floor of the vehicle  50 . 
     The lift platform mechanism  100  includes a support member  102  that extends the length of the expandable room  52 . The support member  102  supports the weight of the expandable room  52 . Expensive finished flooring, such as wood or ceramic is often found in high-end recreational vehicles  50 . The support member  102  extended across the length of the expandable room  52  prevents the floor from bowing and causing extensive damage to the wood or ceramic tile. 
     The support member  102  is connected to one or more arms  112  to pivot the support member  102  between a lowered and raised position. The arms  112  turn about a splined shaft  108  that extends substantially the same length as the tube  102 . The splined shaft  108  provides a common pivot point for all the arms  112  and the support member  102 , thus lowering all points of the expandable room  52  in synchronization, without the need of a separate synchronization cylinder and with fewer lift cylinders  74  that may otherwise be needed. 
     Illustrated in  FIG. 8 , an actuator  74  is pivotally connected to the arm  112  at a pivot point  116 . In this embodiment the actuator  74  is a hydraulic cylinder  74  (the hydraulic system will be discussed more thoroughly below). When the operating rod or piston  74   a  of the hydraulic cylinder  74  extends and retracts, the support member  102  rotates about the splined shaft  108  between a raised and lowered position. 
     The hydraulic cylinder  74  is pivotally connected near its base to a bracket  115  at a pivot point  114 . As the piston  74   a  of the hydraulic cylinder  74  extends outward it rotates the arm  112  and the support member  102  ninety degrees. 
     In one embodiment multiple lift stations  200  are distributed along the length of the expandable room  52 , depending on the lift capacity required. However, the invention herein disclosed is operable with fewer hydraulic cylinders  74  because the support member  102  distributes the lifting force across the length of the expandable room  52  and the splined shaft  108  synchronizes the lifting. 
     In another embodiment, a lift station  200  can be located at each end of the support member  102  or, alternatively an end idler  106  may be used to support the ends of the support member  102  as needed. The end idler  106  is used on the end of the support member  102  to extend a section of the support member  102  and the splined shaft  108  beyond a lift station  200 . This allows the support member  102  to support areas of the expandable room  52 , where installation of a lift station  200  would be difficult. For example, it is common for an expandable room  52  to extend over the top of a wheel well where it may not be possible to attach a lift station  200 . The end idler  106  allows the support member  102  to extend into such an area. 
     In another embodiment, reduced friction surfaces  104 , such as bearing pads  104  are placed on the engaging surfaces of the support member  102 . The bearing surfaces provide a reduced friction surface for the expandable room  52  to slide on. 
     Referring to  FIG. 9 , an embodiment of a hydraulic circuit for the invention is illustrated. One skilled in the art will recognize that the invention is not limited to the circuit configuration shown in the illustrated embodiment. Further, any suitable actuator may be used, including electric and pneumatic. The lift station cylinders  74  and main cylinders  18  are powered by a single regenerative circuit. As is known in the art, in a regenerative circuit there is pressure on the cap side  83  and the rod side  81  of the system while the cylinders  18  are extending (the expandable room  52  is retracting). However, there is only pressure on the rod side  81  when the cylinders  18  are retracting (the expandable room  52  is extending). In a regenerative circuit, the cap  83  and rod  81  sides of the system are connected so that flow into one side requires a flow out of the other side creating a circular circuit. 
     The rod side  81  connection from the manifold  80  connects to the lift station cylinders  74 , the synchronizing cylinder  82 , and then to one end of each main cylinder  18  that extends and retracts the room. The cap side  83  connections from the manifold  80  connect to a valve  88  on the end of the synchronizing cylinder  82 . The valve  88  connects to the cap ends of lift station cylinders  74  through a check valve that allows flow to the lift station cylinders  74 , but not from the lift station cylinders  74  to the manifold  80  until the valve  88  is opened when the synchronizing cylinder  82  is fully extended. The valve  88  also connects to a valve  91  on one of cylinders  74  through the line  92 . Valve  91  does not allow flow to cap side  93  until lift platform cylinder  74  is fully extended. Fluid is allowed through a check from cap side  93  to line  92 . The rod sides of lift platform cylinders  81  are connected to the synchronizing cylinder  82  through a “T” junction. 
     When the expandable room  52  retracts, pressure is supplied to both the cap  83  and rod  81  side of the manifold  80 . As discussed above, the valve  91  prevents fluid from flowing from the synchronizing cylinder  82  to the main cylinders  18  until lift platform cylinders  74  are extended. The only route available for fluid flow is through the cap side  83 . The expandable room  52  is raised by pressure from the manifold  80  through lines  90 , which extends the lift station cylinders  74 . 
     When the pistons  74   a  of the lift station cylinders  74  fully lift the room  52 , the valve  91  will open and allow pressure to act upon the main cylinders  18  to allow the main cylinders  18  to begin to extend. As is know in regenerative hydraulic circuits, even though there will be equal pressure on either side of the main cylinder  18  piston, the difference in areas creates more force on the side of the piston to extend the cylinder  18 , which allows the room  52  to retract. 
     When room extension is activated, pressure is only supplied from the rod side  81  of the manifold  80 . The cap side  83  of the system is dumped to the tank. Pressure pushes on the rod side  81  of the main cylinders  18  and begins to retract the cylinders  18 . The fluid being pushed out of the main cylinders  18  flows freely through the valve  91  in the lift station cylinders  74  and synchronizing cylinder  88 . As the expandable room  52  is being extended, the lift platform cylinder pressure is locked in by valve  88  until synchronizing cylinder  82  is fully extended and opens valve  88 . 
     Once valve  88  opens, cap pressure in the lift station cylinders  74  is dumped to tank, and pressure from rod  81  retracts lift station cylinders  74  until room  52  drops down into position where the interior and the expandable room  50  floor  12   a  are flush. 
     While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it should be understood by those of ordinary skill in the art that various changes, substitutions and alterations can be made herein without departing from the scope of the invention as defined by appended claims and their equivalents. The invention can be better understood by reference to the following claims.