Abstract:
An in-vehicle lift mechanism has a heavy duty drive assembly suitable for lifting heavy loads, such as all terrain vehicles, motorcycles and other motorized equipment and vehicles. The lift mechanism has four corner posts that are fixed to the vehicle and guide a support platform. The drive assembly includes a motor that drives a screw to engage a nut secured to a movable pulley carriage. As the screw turns, the pulley carriage translates relative the platform to either let out or take up cabling allowing the platform to be raised or lowered. The mechanism uses multiple cables, the ends of which are secured in fixed positions, one end being fixed relative to the platform and one fixed relative to the vehicle. A plurality of stationary position pulleys route the cables between the platform and the posts.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims benefit to U.S. Provisional Patent Application No. 60/806,359, filed on Jun. 30, 2006. 
     
    
     STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Technical Field 
         [0004]    The present invention relates to recreational vehicles, and more particularly to lifting mechanisms for raising and lowering objects, particularly heavy loads, within the interiors of such vehicles. 
         [0005]    2. Description of the Related Art 
         [0006]    In order to increase the available interior space of recreational vehicles or trailers, slide-out sections, such as rooms or closets, can be made integral with the structure of the vehicle or trailer. These slide-out sections 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 vehicle, concealed from exterior view, and the end wall forms a portion of the vehicle&#39;s exterior side wall. During transit, these sections are retracted and stored in the interior of the vehicle, with the exterior wall of the slide-out section being flush with the exterior of the vehicle. To use the slide-out section, the vehicle is first parked and leveled. The slide-out room is then slid outward from the vehicle, thereby increasing the interior space of the vehicle. Various drive assemblies exist to extend and retract the slide-out sections. These drive assemblies can be manual or powered, including hydraulics, pneumatics, electronics, simple gearing mechanisms, cable and pulley arrangements, or various combinations thereof. U.S. Pat. No. 6,254,171 discloses one type of operating mechanism for a slide-out room. Slide-out room assemblies can add prohibitive cost and weight to a vehicle such that other methods must be employed to increase interior seating and like space. Moreover, even if the vehicle is equipped with a slide-out room additional interior space may be desired in the slide-out room. 
         [0007]    Another way to increase interior space in such vehicles is to change the vertical position of certain objects at the vehicle interior, such as furniture and other such items. The objects can be raised out of the way when not used, but otherwise lowered while being used. This allows floor space and living space to be cleared of unnecessary objects without eliminating the presence of those objects from within the vehicle. 
         [0008]    In-vehicle lift mechanisms of the type that are mounted within the interior of a trailer or other vehicle for raising and lowering a platform are known. U.S. Provisional Patent Application No. 60/584,625, filed Jul. 1, 2004, describes one such lift mechanism, which is specially suited for raising and lowering furniture such as a bunk bed and therefore it has a capacity to suit that function, for example approximately  300  pounds. This application is hereby incorporated by reference as if fully set forth herein for its disclosure of the lift mechanism. 
         [0009]    A need exists for a heavy duty lift mechanism that is capable of lifting heavier loads, such as an all terrain vehicle, motorcycles, and the like, items which are likely to be put into a recreational vehicle, trailer, or “toy hauler”, to more efficiently use the volume within the trailer or other vehicle. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention provides a lift mechanism for raising and lowering a platform in an interior of the vehicle. The lift mechanism includes a frame and a support member supporting the platform and connected to the frame to be vertically movable relative to the frame. It has a drive assembly that drives an elongated flexible member with a first end fixed relative to the frame or vehicle and a second end fixed relative to the platform support. The flexible member is engaged between its ends by at least one movable position guide member and at least one stationary guide member directing the flexible member through at least one turn. The drive assembly moves the movable position guide member relative to the support member to cause the flexible member to adjust the height of the support member. 
         [0011]    The drive assembly can be mounted to the platform or platform support member, and can include a motor drive, a drive screw and a drive nut engaging the drive screw so that they are relatively rotatable. The position of either the drive screw or the drive nut is fixed with respect to the movable guide member, and the motor drive turns the other. For example, the motor drive can turn the drive screw so the drive nut and the movable guide member translate along the length of the drive screw. 
         [0012]    The lift mechanism can also include a carriage rotatably mounting the movable guide member(s) that moves with respect to the support member. The carriage fixedly mounts either the drive nut or the drive screw and travels relative to the support member by the motor rotating the complementary drive screw or nut component. 
         [0013]    The flexible member can be cabling, in one or more sections, and the movable and stationary guide members can be rotatable sheaves or pulleys. Preferably, the cabling includes multiple segments or section, each having one end fixed relative to the support member and another end fixed relative to the vehicle. 
         [0014]    The plurality of movable and stationary sheaves, such as in one preferred form there are at least ten that are stationary and at least two that are movable, define the cable pathway that routes the cable sections from where they are fixed on the support member through the upright posts of the frame to the fixed points on the frame or vehicle. 
         [0015]    Thus, in one preferred form, operation of the drive motor turns the drive screw. The drive screw threads engage the nut fixed in the carriage and cause the carriage to translate along the drive screw relative to the support member. Because one end of each cable is fixed relative to the support member and the other is fixed relative to the vehicle, movement of the carriage (and sheaves mounted thereon) cause the drive assembly to either take up or let out cabling in the vertical direction, and thereby raise or lower the support member. 
         [0016]    The lift mechanism can also include a travel lock out mechanism and a stop mechanism. The travel lock out mechanism prevents the support member from moving relative to the frame. It can have a solenoid that extends and retracts an arm. The solenoid can be mounted to the support member or the frame to engage one or more associated openings in the frame or support member, respectively. The openings can be spaced apart vertically along the vertical posts of the frame so that the support member can be locked at various heights. 
         [0017]    The stop mechanism prevents operation of the drive assembly when an object is beneath the support member. The stop mechanism can be any suitable sensing device, such as a pressure sensitive switch, a light beam and reflector assembly, a photo-eye, and a proximity sensor, that opens the electrical circuit or provides an input signal to a controller for the drive motor so that support member is either stopped or raised when an object is detected beneath the support member. 
         [0018]    The foregoing and other 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 
         [0019]      FIG. 1  is a perspective view of a heavy duty lift mechanism for an interior of a vehicle; 
           [0020]      FIG. 2  is a plan view thereof; 
           [0021]      FIG. 3  is a simplified perspective view showing a cable and drive assembly of the lift mechanism with a support platform (in phantom) shown in a lowered position; 
           [0022]      FIG. 4  is a view similar to  FIG. 3  albeit with the support platform in a raised position; 
           [0023]      FIG. 5  is a sectional view taken along line  5 - 5  of  FIG. 2 ; 
           [0024]      FIG. 6  is a sectional view taken along line  6 - 6  of  FIG. 2 ; 
           [0025]      FIG. 7  is a partial enlarged perspective view showing a pulley carriage of the drive assembly; 
           [0026]      FIG. 8  is a partial sectional view taken along line  8 - 8  of  FIG. 2 ; 
           [0027]      FIG. 9  is a partial sectional view taken along line  9 - 9  of  FIG. 2  showing a stop mechanism in an engaged position; 
           [0028]      FIG. 10  is a view similar to  FIG. 9  albeit showing the stop mechanism in a disengaged position; and 
           [0029]      FIG. 11  is a partial sectional view taken along line  11 - 11  of  FIG. 10 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0030]    Although not shown in the drawings, the present invention is preferably used in a passenger vehicle, such as a tow-along trailer or self-propelled (motorhome) recreational vehicle. The lift mechanism&#39;s  10  robust framing and drive assembly allow it to be used advantageously to vertically elevate heavier loads, on the order of 1,000-2,000 pound loads, such as all terrain vehicle, motorcycles, and the like, and thereby clear floor space in the interior of the vehicle. 
         [0031]      FIG. 1  shows the lift mechanism  10  inverted in what would be an elevated position if not inverted. The lift mechanism  10  can be mounted inside the main vehicle interior or within an extendable and retractable slide-out section of the vehicle to provide further space-saving benefits. Such slide-out sections are well known to have a floor, ceiling, upright end wall and two upright side walls, which form a part of the vehicle exterior when extended. 
         [0032]    Referring now to  FIGS. 1 and 2 , the primary components of the lift mechanism  10  include a drive assembly  12 , a support platform  14 , an upright frame assembly  16 , a flexible drive assembly  18  and a guide assembly  20 . The support platform  14  is a framework of channel members including front  22  and back  24  runners and end channels  26  and  28  and inner channels  30 ,  32 ,  34  and  36 . The channels are joined in any suitable manner, such as by weldment or mechanical fasteners, using any standard joinery, such as overlapped or recessed joints. 
         [0033]    As shown in  FIG. 1 , the upright frame assembly  16  includes four vertical channel members  38  at the four corners of the support platform  14 . The open faces of these channels  38  receive the ends of the front  22  and back  24  channels allowing the support platform  14  to move up and down therein. Wear pads (not shown) can be mounted to the channels, or any bushings, rollers or other friction reducing members, can be used at this junction to facilitate easier and smoother movement. The channels  38  of the upright frame assembly  16  are bolted or otherwise fixed to opposite side walls of the vehicle room or to the floor and/or the ceiling at opposite ends. The top and bottom ends of these channels  38  may be either capped, have clearance or run full height of the room so that the support platform  14  can not be decoupled readily. “Feet” (not shown) at either the bottom, top or both ends of the vertical channels if the lift mechanism is mounted to the floor, ceiling or floor and ceiling, respectively. Each foot can be a solid steel piece or a stack of steel pieces that are disposed between the vertical channels and the flooring or joists or other structural parts of the floor and ceiling. This can provide a more solid connection to the vehicle that mounting the vertical channels to the side walls of the vehicle room, which may have less robust tubular structural members. 
         [0034]    The height adjustment of the support platform  14  is accomplished by actuating the drive assembly  12  to move the flexible drive assembly  18 . As shown in  FIGS. 1 and 2 , the drive unit  12  is preferably a suitable bidirectional electric motor and gear box drive unit  40  bolted to a motor mount flange that is welded to the support platform  14  between the innermost channels  32  and  34 . The motor drive unit  40  turns a long drive screw  50  that threads into a drive nut  52  mounted in a traveling pulley carriage  54 . To bear the force of heavier loads (e.g., 1,000-2,000 lbs. or greater) carried by the support platform  14 , the drive screw  50  should mount via a spherical thrust bearing of tapered or cylindrical roller type and an angular compensating washer configuration  55 , which preferably includes a roller bearing, a spherical washer and a thrust bushing. This assembly allows the high thrust loading of the higher platform loads to be transferred successfully to the motor/gear box of the drive unit  40 . 
         [0035]    The drive unit  40  is mounted in fixed relation to the support platform  14 , and the carriage  54  translates with respect to the support platform  14  along the drive screw  50  as it is turned because the drive nut  52  is held in the carriage  54  against rotation so that the drive screw  50  turns relative to the drive nut  52 . As shown in  FIG. 7 , the carriage  54  has two support tubes  60  and  62  that extend between two end brackets  64  and  66 . The end bracket  66  mounts two double groove sheaves or pulleys  68  and  70 , which move along with the carriage  54  and can rotate about a vertical axis relative to the carriage  54 . 
         [0036]    As mentioned, operation of the drive unit  40  turns the drive screw  50  which moves the flexible drive assembly  18 . As shown in  FIGS. 2-4 , in the preferred embodiment the flexible drive assembly  18  is an assembly of four cables, including two long cables  72  and  74  and two shorter cables  76  and  78 . One end of each cable  72 - 78  is fixed to a plate  79  mounted to the support platform  14 . The other end of each cable  72 - 78  is fixed either to an upper end of the upright frame assembly  16  or to the vehicle room frame (such as ceiling joists). 
         [0037]    Rotation of the drive screw  50  by the drive unit  40  causes the carriage  54  to travel along the drive screw  50  toward the drive unit  40 , which has the effect of taking up cable and thereby raises the support platform  14  upward. The opposite rotation of the drive screw  50  causes the carriage  54  to travel along the drive screw  50  away from the drive unit  40  which lets out cable and lowers the support platform  14 . 
         [0038]    As the support platform  14  is raised and lowered, the cables  72 - 78  of the flexible drive assembly  18  move around the support platform  14  and upright frame assembly  16  as directed by the guide assembly  20 , and thereby raise or lower the support platform  14 . 
         [0039]    As shown in  FIGS. 3-7 , the guide assembly  20  includes number of pulleys or sheaves, including both the movable position pulleys  68  and  70  as well as ten stationary pulleys  80 - 98 , all of which can be rotatable mounted on stub shafts  99  and retained by clip pins  101  (see  FIG. 8 ). Like the movable pulleys  68  and  70 , stationary pulleys  80  and  82  are double grooved, each engaging two of the cables. All of the other stationary pulleys  84 - 98  are single grooves, each engaging only one cable. The two double groove stationary pulleys  80  and  82  and single groove stationary pulleys  84 ,  86 ,  88  and  90  are mounted to the support platform  14  to rotate about vertical axes. Singe groove stationary pulleys  92 - 98  are mounted to the support platform  14  to rotate about horizontal axes. 
         [0040]    The arrangement of the guide assembly  20  defines the cable pathway as shown in  FIGS. 3 and 4 . The guide assembly  20  routes the cables  72 - 78  from the carriage  54  generally through the horizontal plane of the support platform  14  and then up vertically through the upright frame assembly  16 . In particular, all of the cables  72 - 78  extend from the fixed plate  79  and wrap 180 degrees around the two double groove movable pulleys  68  and  70  on the carriage  54 , with long  72  and short  76  cables engaging pulley  68  and long  74  and short  78  cables engaging pulley  70 . Then, the cables engage the associated stationary double groove pulleys  80  and  82  and turn  90  degrees generally along member  24  of the support platform  14 . The long cables  72  and  74  engage pulleys  84  and  86 , and run back at an oblique angle to pulleys  88  and  90 , respectively, at the rear corners of the support platform  14 , then turn upward by wrapping  90  degrees around pulleys  96  and  98 , respectively. The short cables  76  and  76  run from the stationary double groove pulleys  80  and  82  and engage pulleys  92  and  94 , respectively, at two corners of the support platform  14  where they turn 90 degrees upwardly. 
         [0041]    In the preferred embodiment, translation of the pulley carriage  54  along the drive screw  50  causes the support platform  14  to be raised or lowered. The particular pulley arrangement described herein causes the support platform  14  to move about twice the distance that the carriage  50  travels. 
         [0042]    Thus, an object can be raised up out of the way when not being used, which increases the effective living and floor space in the room inside the vehicle. When needed, it can be lowered into place for use. The operation can be performed using a simple wall switch mounted in a convenient location. The robust drive screw/nut and traveling pulley carriage arrangement allows the mechanism to lift heavier loads, such as an all terrain vehicle, motorcycles, and the like, items which are likely to be put into a recreational vehicle or trailer to more efficiently use the volume within the trailer or other vehicle. 
         [0043]    The lift mechanism of the present invention can include additional safety features designed to prevent the support platform  14  from inadvertently lowering, particularly when an object or person is located below the support platform  14 . Various space monitoring devices, such as photo-sensors and the like, can be used to prevent the support platform  14  from being lowered when objects or people are in the space directly below it. 
         [0044]    As shown in  FIG. 1 , in the preferred embodiment described herein, the lift mechanism has a stop mechanism in which a compact light beam generator  100 , as know in the art, is mounted to one of the room walls at one side of the mechanism, and the reflector  102  is mounted to an opposite wall across from and at the same height, preferably 3-6 feet up from the floor, as the light beam generator  100 . This assembly creates a closed electrical path with the light beam passes unobstructed to the reflector  102  and back to an “eye” (not shown) on the light beam generator  100 . The light beam generator  100  is electrically coupled in series to the drive unit  40 . The electrical circuit of the drive unit  40  is opened when the light beam is obstructed by a person or object present across its path, which de-energizes the drive unit  40  and prevents it from being lowered. 
         [0045]    Rather than being simply electrically in series with the drive unit  40 , the light beam generator  100  could be an input to a electronic controller (not shown) which monitors and processes the input as it controls the drive unit  40 . In that case, the input signal from the light beam generator  100  could be considered only when the drive unit  40  is lowering the support platform  14 , and ignored during when the support platform  14  is being raised. Also, the input signal from the light beam generator  100  could be used by the controller to initiate another event, such as activating an emergency motor brake to immediately stop the support platform  14  or a reverse sequence in which the drive unit is controlled to stop downward movement and begin moving the support platform  14  upward. In any event, a manual override can be required to re-energize the drive unit  40  so that user input is provided to ensure that the area beneath the support platform has been cleared. 
         [0046]    As shown in  FIGS. 9-11 , the lift mechanism also has a lock out mechanism that positively locks the support platform  14  in at a fixed height or vertical position. The lock out mechanism includes at least one, but preferably four, one at each corner, powered solenoids  110 ,  112 ,  114  and  116  that have a pin  118  that can be extended and retracted. Each pin  118  is coupled to an arm  120  extending generally along the axis of the pin. The solenoids  110 - 116  are mounted along one side of the support platform  14  along a common axis and near opposite corners so that when extended the arms  120  can engage same height pairs of openings in the associated vertical channels  38  of the upright frame assembly  16 . The pairs of openings are part of a series of vertically spaced apart openings  130  in the vertical channels  38 . Preferably, the arms  120  have tapered upper ends. 
         [0047]    The pins  118  of the four solenoids are normally extended by internal springs (not shown), thus the normal attitude of the solenoids are extended. This forces the arms  120  into the openings  130  and into engagement with the vertical channels. To raise the platform the arms  129  are left in the spring loaded out position and the taper on one side of the arms  120  allows them to “cam” or slide over the openings  130  in the vertical channels. The bottom of the arms  120 , which is flat, is the only contact area of the arm to the vertical channel, when the platform is at rest. The arms  120  makes a “chunk, chunk, chunk” sound when raising due to each arm  120  slapping into the openings  130 . This sound is used to fine tune the cable length when initially setting up the system. If the four cables are set to the correct length, ensuring the platform is level, the four arms  120  slapping against the vertical channel make one combined “chunk” sound. If the cables are of slightly different lengths, indicating an uneven platform the sound is of four distinct chunk sounds. 
         [0048]    The lock out mechanism can be activated electrically, either by user input via a button or other interface or via a control algorithm, to positively lock the support platform  14  at a given height. The controls for the lock out mechanism allows the support platform  14  to settle down when the desired height or position is achieved on the vertical channels. The controls “know” where the support platform  14  (and thus the arms  120 ) are in relationship to the openings  130  in the vertical channels due to a hall sensor counting the revolutions of the motor. When the platform is raised to a position and the arms  120  snap into the opening  130  of the channels, or in the case of lowering when the solenoids withdraw the arms  120  and redeploy them when a lower switch is released, the controls reactivate the drive unit  40  and settles the platform via the arms  120  onto the bottom edge of the openings  130 . This removes loading from the cables and pulley carriage  54  of the system as well as optimizes the ability of the user to insert manual travel lock pins that captivate the upper movement of the platform for use when the vehicle/trailer is moving. This arrangement thus provides a positive, mechanical lock out supplemental to the drive unit  40  that better prevents unintended lowering of the support platform  14 , which is particularly advantages when lifting heavier loads. 
         [0049]    In addition, sensors can be added to the state of the support platform  14  and provide input to control the lock out mechanism. For example, tilt sensors or acceleration sensors that detect a non-level support platform condition or excessive change in travel speed can be used to rapidly deploy the arms  120  into engagement with same height or any other pair of openings  130  in the channels  38 , and thereby immediately stop movement, particularly downward movement, of the support platform  14 . 
         [0050]    It should be appreciated that merely a preferred embodiment of the invention has been described above. However, many modifications and variations to the preferred embodiment will be apparent to those skilled in the art, which will be within the spirit and scope of the invention. Therefore, the invention should not be limited to the described embodiment. To ascertain the full scope of the invention, the following claims should be referenced.