Abstract:
The present invention provides a slide-out support rail, which is particularly adapted for use as a single set of rails, which may be power operated or manually operated. The slide-out support rail system has an inner telescoping rail with a gear rack mounted on top of the upper wall of the inner rail. The teeth of the gear rack face upwardly and mesh with a pinion gear which is journaled relative to the outer rail above the gear rack.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/196,963 filed Apr. 13, 2000. 
    
    
     STATEMENT OF FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to slide-out rooms for recreational vehicles, and particularly to slide-out room support systems in which a single set of rails is required to support the room. 
     2. Discussion of the Prior Art 
     In order to increase available interior space of recreational vehicles, e.g. motor homes and trailer homes, slide-out rooms or sections are provided. During transit, these rooms are retracted and stored in the interior of the vehicle or trailer, with the exterior end wall of the slide-out room approximately flush with the adjacent exterior wall of the vehicle or trailer. To use the slide-out room, the vehicle is parked and leveled. The slide-out room is then slid outward from the vehicle using the slide-out room support system thereby increasing the interior space of the vehicle. 
     The slide-out rooms usually include a floor, a roof, an end wall and one or more side walls. In the retracted position the roof, floor and side walls are typically inside the stationary part of the vehicle, concealed from exterior view, and the room end wall forms a portion of the vehicle&#39;s side wall. A gasket is usually provided which is compressed between the inner ends of the slide-out room walls (which may include the floor) and the vehicle walls so as to keep wind, rain, dirt and bugs out when the vehicle is extended. A similar set of gaskets may also be provided between the two outer walls of the respective vehicle and room to seal the room when it is retracted. 
     Sets of telescoping support rails are usually used to support the slide-out room and these rails may be power driven in and out or manually pulled out and pushed back in. Any number of sets of rails may be used, depending upon the size of the room to be moved. 
     When two or more sets of rails are used, they are spaced apart and mechanically linked to one another so that they extend or retract together. They may be mechanically linked, for example, with a rack and gear system in which each inner rail is provided with a rack and pinions engaging the racks are connected by a shaft, or with a cable and pulley system, to ensure that the rails extend and retract together. 
     For small rooms, such as a wardrobe or closet, a single rail is sufficient to support the room and may be all that there is space for. However, a problem with using a single rail is racking of the inner rail relative to the outer rail from side to side. Another problem is providing a single rail with sufficient strength which is still of a low profile to fit in a tight space beneath the room being moved. The present invention provides a solution to these problems. 
     SUMMARY OF THE INVENTION 
     The present invention provides a slide-out support rail system that is particularly adapted for use as a single set of rails, which may be power operated or manually operated. 
     In particular, the invention provides a slide-out support rail system for supporting a slide-out section of a recreational vehicle. The system includes an inner rail mounting a rack on top of a longitudinally extending upper wall so as to mesh with a drive pinion. An outer rail slidably mounts the inner rail on a pair of support rollers spaced apart longitudinally to support the inner rail and maintain engagement of the rack and pinion. 
     The gear rack of the telescoping inner rail has teeth that face upwardly and mesh with the pinion gear which is journaled relative to the outer rail above the gear rack. Rollers are preferably provided on both sides of the pinion which roll along the top side of the inner rail so as to counteract upward forces exerted upon them, which would otherwise be transferred to the pinion gear. Another set of rollers is also provided at the outer end of the outer rail beneath the inner rail, to support the inner rail. 
     To assure engagement of the rack with the pinion, the inner rail is made in three pieces, not including the gear rack. As such, the inner rail consists of an open U-channel, which opens upwardly, a rectangular tube approximately centered in the open U-channel, and a top wall plate which covers the tube and extends between the side walls of the U-channel. The rectangular tube is positioned beneath the gear rack, so that the tooth forces exerted on the gear rack by the pinion, which tend to push the gear rack away from the pinion, are counteracted not only by the U-channel and the top plate, but also by the rectangular tube within the U-channel. 
     In addition, directly beneath the pinion gear which drives the gear rack, another roller is provided, to maintain the gear rack in meshing engagement with the pinion. 
     In another aspect, the inner rail is made at least two times as wide as it is tall. This improves the resistance to racking of the inner rail. 
     In addition, between the sidewalls of the outer rail and the sidewalls of the inner rail, wear pads are preferably provided, which also contribute to the resistance to racking of the entire unit. 
     The foregoing and other objects and advantages of the invention will appear in the detailed description which follows. In the description, reference is made to the accompanying drawings which illustrate a preferred embodiment of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a set of slide-out support rails of the invention; 
     FIG. 2 is a longitudinal cross-sectional view of the rails of FIG. 1 mounted in a recreational vehicle so as to move a room in and out; 
     FIG. 3 is similar to FIG. 2 but shown with the room extended; 
     FIG. 4 is a top plan view of the rails of FIG. 1; 
     FIG. 5 is a fragmentary detail view showing the drive system for the rails of FIG. 1; 
     FIG. 6 is a partial cross-sectional view from the plane of the line  6 — 6  of FIG. 3; 
     FIG. 7 is a partial cross-sectional view from the plane of the line  7 — 7  of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, a set of slide-out rails  10  of the invention includes an inner rail  12  and an outer rail  14 . The outer rail  14  is an upwardly open U-shaped channel with a forward cover  16  welded to it covering its forward portion and straps  18 ,  20  and  22  welded to it in its rear portion. Cover  16  is welded or otherwise suitably affixed to frame member  24  of the vehicle and straps  18  and  20  are welded or otherwise suitably affixed to frame member  26  (FIG. 2) of the vehicle. Alternatively, right angle tabs  27  could be welded onto both sides of the rail  14  and the tabs bolted to the stationary floor  68 , on top of the floor  68 , and the movable floor  66  provided above the unit  10 . In such a case, the floor  66  is elevated above the floor  68 , but this is commonly done, for example, for a slide-out bedroom. 
     An adjustable stop  28  in the form of a threaded bolt is affixed to the rearward most strap  22 . Another bolt  30  is screwed into the rearward end of the inner rail  12  which abuts the bolt  28  in the fully retracted position. Another adjustable stop  32  in the form of a bolt is screwed into drive housing  34  which is welded or otherwise suitably affixed to the outer rail  14 . The bolt  30  abuts the adjustable stop  32  in the fully extended position as shown in FIG.  3 . 
     The inner rail  12  is supported in the outer rail  14  by two sets of rollers  40  and  42 . Both sets of rollers  40 ,  42  span the outer rail  14  and are supported thereby by appropriate bearings. The roller  42  is provided at the outward end of the rail  14  and the roller  40  is provided directly beneath the axle  44  on which the drive gear  46  and rollers  48  (FIGS. 5 and 6) are mounted. The shaft  44  is journaled in the drive housing  34  with rollers  48  rotatable relative to the shaft  44  and the gear  46  affixed to the shaft  44  to rotate therewith. Shaft  44  may be turned by an electric motor  50  or by a manual crank  52 . Motor  50  is mounted to flange  63  and has its shaft engaged with shaft  54  coupler  60  to turn shaft  54  and therefore bevel gear  56 , which meshes with bevel gear  58  which is affixed to the shaft  44 . Shaft  54  is also journaled to the housing  34 . Coupler  61  on the end of shaft  44  is engagable by the handle  52 . Referring particularly to FIGS. 2 and 3, a bracket  62  on the end of the inner rail  12  is affixed to the slide-out room  64 , the room  64  having floor  66  which rides on top of stationary floor  68 . 
     Gear  46  meshes with rack  70  which is welded or otherwise suitably affixed to top wall  72  of inner beam  12 . Inner beam  12  also includes U-shaped channel  74  which is welded to the top wall  72  and rectangular stiffening tube  76 , which is also welded to the channel  74  and/or the top wall  72  directly beneath the rack  70 . The tube  76  provides stiffness to keep the rack  70  from bowing away from the gear  46 . The roller  40  also supports the rack  70  to keep it in engagement with the gear  46 . 
     Referring to FIG. 7, wear pads  80  which may be made of a lubricious plastic such as nylon or Teflon are provided at positions spaced along the length of the outer rail  14  between the inner rail  12  and the outer rail  14  so as to guide the rail  12  inside the rail  14 . The pads  80  help counteract racking side to side of the rail  12  inside the rail  14 , which is important since the rails  12  and  14  may be the only set of rails supporting the room  64 . The low profile of the rail  12  creates a short and wide profile which has a high transverse bending strength. The rack  70  and tube  76  contribute, along with the members  72  and  74 , to the ability of the inner rail  12  to support the weight of the room  64 . 
     Thus, in a slide-out system of the invention, the rack is affixed to the top of the inner rail, and a pinion gear in meshing engagement above the rack drives the inner rail in and out. A roller is provided on each side of the rack, preferably on the shaft of the pinion gear. In a preferred aspect, the inner rail is made relatively short and wide, for example at least two, and preferably closer to at least three, times as wide as it is tall. The rack is centered on the top wall of the inner rail, and a reinforcement is provided below the top wall directly beneath the rack, to maintain engagement of the rack with the pinion. A support roller is provided beneath the bottom wall of the inner rail, directly below the pinion, to support the inner rail and rack in engagement with the pinion. 
     The low profile of the inner rail contributes to its ability to resist racking, fit a small vertical space, and by itself support a small room. Wear pads affixed to the outer rail between the sides of the inner and outer rails are spaced along the length of the rails for guidance against racking of the inner rail inside of the outer rail. 
     Many modifications and variations to the preferred embodiment described will be apparent to those skilled in the art. Therefore the invention should not be limited to the embodiment described. Rather, the following claims should be referenced to determine the scope of the invention.