Abstract:
A mechanism for activation of an articulating bed incorporates at least one mattress support plate and a pair of side rails. A rack is attached to each side rail and a torque tube extends between the side rails with a pinion gear at each end engaging a respective one of the racks. An actuator imparts translational motion to the torque tube perpendicular to its axis. Elevation bars connected to the torque tube and the support plate are angularly displaced by translation of the torque tube.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    This invention relates generally to the field of adjustable beds and more particularly to a structure for an articulating bed having matched gear drives operable through a single actuator for mechanism reliability. 
         [0003]    2. Description of the Related Art 
         [0004]    Articulating beds have long been used in hospital and healthcare facilities to allow positioning of a patient in a reclining position, sitting position, elevated leg position or combinations of these positions. General usage of articulating beds has been rapidly expanding due to the comfort and convenience available from adjusting the bed to desired positions for reading, general relaxation or sleeping. 
         [0005]    The mechanical structure and drive mechanisms for such articulating beds must be able to support the weight of both a mattress and the occupant. Due to the size, weight, fabrication materials and configuration of the mattress and supporting structure, maintaining rigidity in the system may also be challenging. Prior art systems rely on multiple motors and/or lever mechanisms to provide adjustment of the head and foot elements of the bed. Typically drive motors or other actuation component must be placed symmetrically to avoid binding created by torsional flexibility of the mattress and supports. The cost, complexity and weight of these systems can be undesirable. 
       SUMMARY 
       [0006]    The embodiments disclosed herein overcome the shortcomings of the prior art by providing an actuating mechanism for an articulating bed which incorporates a torque tube having a pinion gear at each end and an actuator imparting translational motion to the torque tube perpendicular to its axis. A rack associated with each pinion gear is attached to an associated side rail and at least one elevation bar is connected to the torque tube and a mattress support plate. The elevation bar is angularly displaced by translation of the torque tube to elevate the support plate. 
         [0007]    In various aspects of the embodiment, the actuator comprises a linear actuator which is attached to one side rail and incorporates an end fitting having a bore to receive the torque tube for rotational motion. In another aspect of the embodiment, the at least one elevation bar is two symmetrically positioned elevation bars, each elevation bar having an end fitting with a bore to receive the torque tube for rotational motion. 
         [0008]    In additional aspects of the embodiments, each side rail has a top flange, a bottom flange and a plate extending from the top flange to the bottom flange as an external shield for the associated rack and pinion. An internal shield is associated with each side rail and has a top plate received over the top flange of the side rail and a side plate depending from the top plate with an aperture to receive the torque tube. The internal shield translates with the torque tube. 
         [0009]    In an alternative embodiment, the actuating mechanism employs a toothed belt fixed at a first end to the side rail and engaging a gear on the torque tube. A second end of the toothed belt engages and is wound on a rotating sprocket. 
         [0010]    In use, the embodiments provide an articulating bed which employs at least one mattress support plate and a pair of side rails vertically spaced from the support plate. A rack is attached to each side rail and a torque tube extends between the side rails with a pinion gear attached at each end to engage a respective one of the racks. An actuator imparts translational motion to the torque tube perpendicular to an axis of the torque tube. At least one elevation bar is connected to the torque tube and the support plate which is angularly displaced by translation of the torque tube to elevate the support plate from a horizontal position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    These and other features and advantages of the present invention will be better understood by reference to the following detailed description of exemplary embodiments when considered in connection with the accompanying drawings wherein: 
           [0012]      FIG. 1  is a top view of an exemplary embodiment implementing a linear actuator for elevating one portion of the bed; 
           [0013]      FIG. 2  is an isometric view of the drive components for the embodiment of  FIG. 1 ; 
           [0014]      FIG. 3  is detail end view of the torque tube and synchronization elements of the embodiment as shown in  FIG. 2 ; 
           [0015]      FIG. 4A  is an isometric view of an alternative embodiment of the torque tube and synchronization elements of the embodiment; 
           [0016]      FIG. 4B  is a section view of the alternative embodiment of  FIG. 4A ; 
           [0017]      FIG. 4C  is an isometric view of the embodiment of  FIG. 4A  with a shield for the operating components 
           [0018]      FIG. 5  is an isometric view of the safety shield of  FIG. 4C ; 
           [0019]      FIG. 6A  is an top view of the embodiment employing a mirrored linear actuator drive system for positioning of both upper and lower bed elements; 
           [0020]      FIG. 6B  is a isometric view of the embodiment of  6 A employing a mirrored linear actuator drive; 
           [0021]      FIG. 7A  is an isometric view of the embodiment of  FIG. 6A  with the head element raised to a medium height and the foot element flat. 
           [0022]      FIG. 7B  is a side section view of the embodiment of  FIG. 7A ; 
           [0023]      FIG. 8A  is an isometric view of an alternative gear drive arrangement with a linear actuator drive; 
           [0024]      FIG. 8B  is an isometric view of the alternative gear drive arrangement with a sprocket drive; 
           [0025]      FIG. 9A  is a detailed side view of a collapsing safety corner for use with the embodiments described; 
           [0026]      FIG. 9B  is a detailed side view of the safety corner in the activated condition; 
           [0027]      FIG. 10  is a section end view of the collapsing safety corner elements of  FIG. 9A ; 
           [0028]      FIG. 11  is a top view of the collapsing safety corner of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    Embodiments shown in the drawings and described herein provide an actuation system for an articulating bed which simplifies the drive components and actuation requirements while preventing torsional effects which might otherwise create binding of the actuation mechanism. Sufficient torsional support for the movable portions of the bed is also provided for rigidity with minimal structural weight or complexity. Referring to  FIG. 1 , bed  10  incorporates a frame having side rails  12   a  and  12   b . For the embodiment shown in the drawings corner posts  14  are present at the end of the side rails and receive end rails  16   a  and  16   b  to complete the frame. And actuating mechanism  20  provides for elevation of a selected portion of a mattress as will be described in greater detail subsequently. The actuating mechanism may be driven by a single actuator  22 , which for the embodiment shown is a linear actuator having a telescoping rod  24  extending from a barrel  26 . A motor  28  provides rotation of the barrel for extension and retraction of the rod. In alternative embodiments, multiple actuators may be employed for each movable section. 
         [0030]    As best seen in  FIG. 2 , telescoping rod  24  incorporates an end fitting  30  which receives a torque tube  32  through a bore  31  (best seen in  FIG. 4B ) for rotational motion. A pinion gear  34   a  is attached to a first end of the torque tube and rides on a rack  36   a  attached to a lower flange  38   a  of side rail  12   a . As shown in  FIG. 3 , a second end of torque tube  32  carries a pinion gear  34   b  which rides on a rack  36   b  attached to a lower flange  38   b  of the second side rail  12   b . Elevation bars  40   a  and  40   b  are carried by end fittings  42   a  and  42   b . End fittings  42   a  and  42   b  incorporate bores  44   a  and  44   b  respectively to receive the torque tube  32  which rotates within the bores. 
         [0031]    Extension and retraction of actuator rod  24  causes the torque tube to translate in a direction perpendicular to its axis  33  and parallel to rails  12   a  and  12   b . Pinion gears  34   a  and  34   b  riding on racks  36   a  and  36   b  create rotation in the torque tube thereby maintaining alignment. Translation of the torque tube results in angular rotation of the elevation bars to raise and lower a support plate for the mattress portion being elevated as will be described in greater detail subsequently. The structural support by the multiple elevation bars supported from the torque tube provides good torsional stability for the elevating head portion of the bed without requiring excessive structural weight or complexity. 
         [0032]    Actuation mechanism  20  allows a single actuator to uniformly position the symmetrical elevation bars without any torsional binding which could occur based on the flexibility of the support plate and mattress. The use of the pinion gears at each end of the torque tube allows non-symmetrical positioning of the linear actuator thereby allowing attachment of the actuator and motor to a single side rail without additional cross-rail structural elements. The actuator may be located at any position along the torque tube which may be most convenient based on the available mounting structure. 
         [0033]    Additional details of an exemplary embodiment for elements of actuation mechanism  20  are shown in  FIGS. 4A ,  4 B and  4 C. An end cap  50  is attached to the outboard surface  52  of the pinion gear  34   a . The end cap has a diameter  54 , greater than diameter  56  of the pinion gear, which extends over an outer edge  58  of rack  36   a  to prevent motion of the pinion gear and attached torque tube along the axis of the torque tube. This additionally maintains engagement of the pinion on the rack by preventing the pinion from jumping off the rack due to the proximity of the cap to the upper flange  72   a  of the side rail and prevents the pinion from abraiding the side rail. Lock rings  60  and  62  are received over the torque tube inboard and outboard, respectively, of end fittings  44   a  and  30  to avoid canting of those fittings with respect to the torque tube thereby avoiding binding. Attachment of the locking rings and pinion gear to the torque tube may be accomplished using diametric pins  64  or set screws. A shank  66  extending from pinion gear  34   a  is received within a central bore of the torque tube and is pinned using a common diametric pin with lock ring  62  for the embodiment shown. 
         [0034]    A plastic shield  68 , also shown in  FIG. 5 , incorporates a top plate  70  which rides on an upper flange  72   a  of side rail  12   a . An aperture  74  in side plate  76  receives torque tube  32 . As torque tube  32  translates along the rails, shield  68  is drawn along the side rail thereby providing complete shielding of the rotating interface between the pinion gear and rack to avoid any pinching hazard. The configuration of side rails  12   a  and  12   b  with plates  78   a  and  78   b  extending between the top and bottom flanges of each side rail shields the actuation mechanism from the exterior of the bed. 
         [0035]    The configuration of the actuation mechanism with use of a single actuator allows simple configuration for multiple portions of the mattress to be separately elevated. As shown in  FIGS. 6A and 6B , a first actuation mechanism  20   a  may be incorporated for elevation of a head portion while a second actuation mechanism  20   b  may be incorporated for elevation of a foot portion. The embodiment shown in  FIGS. 6A and 6B  employs symmetrical mounting of the actuators for the actuation mechanisms on opposite rails of the bed however in alternative embodiments the actuators may be mounted to a single rail. As best seen in  FIG. 6B  the side rails, end rails and associated corner blocks are supported by bed legs  77  for the embodiment shown but may be floor mounted. As shown in  FIGS. 7A and 7B , a support plate  80  for the head portion of the mattress rests in the horizontal position on corner blocks  14 , or alternative extensions thereof as subsequently described with respect to  FIGS. 9A. 9B ,  10  and  11 , vertically spaced from the side rails and is rotated about a pivot  82  by the elevation rods which are angularly displaced as shown in phantom for a first retracted position  40   w  and a second elevated position  40   x  created by translation of the torque tube responsive to the first actuator  22   a . Pinned connection of the elevation rods to the torque tube at their base and to the support plate at an end distal from the base causes translation of the base with the torque tube and resultant angular rotation due to the compressional rigidity of the rods. Similarly a second support plate  84  for a foot portion of the mattress is rotated about a pivot  86  by the elevation rods of the second actuation mechanism as shown for a first retracted position  40   y  and, in phantom, a second elevated position  40   z.    
         [0036]    An alternative to the linear actuator described with respect to the previous embodiments is shown in  FIGS. 8A and 8B . Torque tube  32  incorporates a first gear portion  90  which receives a mating toothed belt  92 . The belt is fixed at a first end  94  to the lower flange of the side plate. A second end  96  of the belt is drawn to a linear actuator  22  by rod  24  as shown in  FIG. 8A  or wound on a rotating sprocket  98  as shown in  FIG. 8B  resulting in translation of the torque tube. The sprocket may be driven by a standard rotating motor (not shown). While a toothed belt is shown for the embodiment of  FIG. 8  a chain of alternative engagement mechanism may be employed in alternative embodiments. Pinion gear  34   a  is shown on the end of the torque tube for symmetrical operation as in the previously described embodiment. However, in alternative embodiments, the separate pinion gear may be eliminated by relying on the toothed belt to create the rotation of the torque tube with the pinion gear at the opposite end of the torque tube assuring the matching rotational velocity and translation of that end of the torque tube. 
         [0037]    Additional safety elements are incorporated in the embodiments, shown in the drawings as previously described, to prevent openings in the structure where, for example, the mattress and mounting plates may be fixed above the level of the side rails and other frame elements of the bed. As shown in  FIGS. 9A and 9B ,  10  and  11 , a resilient member such as a flat coil spring  100  is provided extending upwardly from each corner block  14 . Plate  80  supporting the mattress head portion, for example, rests on the top of the flat coil springs in the horizontal position. A skirting strip  102  which may be plastic, heavy-duty fabric, or other suitable material extends between the coil springs. A fabric skirt  104  is connected to the skirting strip and draped downwardly attaching to the side rail. The fabric skirt prevents insertion of objects or body parts into the aperture between the plate and side rail. Additionally, attachment of the skirt and skirting strip to the flat coil springs allows resilient deformation should any object or body part be inserted over the skirting strip when the plate is rotated upwardly using the actuators as previously described and then trapped by a downward rotation of the plate. As shown in in  FIG. 9B  engagement by an intruding element  106 , such as an arm or hand, would result in depression of the skirting strip with a resultant inward deformation of the flat coil spring as noted by element  100 ′. This prevents any significant pressure on the intruding object. Flat coil springs  100  provide additional vertical support for plate  80  supplementing support provided by the elevation bars. 
         [0038]    Having now described various embodiments of the invention in detail as required by the patent statutes, those skilled in the art will recognize modifications and substitutions to the specific embodiments disclosed herein. Such modifications are within the scope and intent of the present invention as defined in the following claims.