Abstract:
A sliding subframe mounted to the derriere-supporting section of an articulating bed is adapted to translate the rotational axis of the torso-supporting section of the bed toward the headframe as the torso-supporting section is raised to an inclined position, and back toward the footboard as the torso-supporting section is lowered to a level position. This mechanism reduces compression of the lumbo-sacral area of the patient during bed articulation.

Description:
RELATED DISCLOSURES 
   This invention relates to, and this application incorporates herein by reference, the disclosure by Eduardo R. Benzo, Rodolfo W. Ferraresi, and Mario C. Eleonori entitled Device and Method for Release Lumbar Pressure in Adjustable Beds (Slideback) filed as part of the Patent and Trademark Office&#39;s Document Disclosure Program and given DDP number 610041. 
   FIELD OF THE INVENTION 
   This invention relates generally to specialized beds and surfaces, and more particularly, to articulating hospital beds. 
   BACKGROUND OF THE INVENTION 
   Normally in adjustable specialty beds, when the torso is elevated more than 30 degrees, the lower portion of the torso surface compresses the lumbo-sacral area and induces the patient to slide toward the footboard area of the bed. This not only causes discomfort, but also increases the risks of shear-lesion and pressure ulceration. 
   Accordingly, there is a need for a mechanism that minimizes compression of the lumbo-sacral area during articulation of the torso surface toward an inclined position. 
   SUMMARY OF THE INVENTION 
   An axis displacement mechanism is provided that translates the rotational axis of the torso-supporting section of a multi-sectioned articulating specialty bed toward the headboard as the torso-supporting section is raised to an inclined position. This mechanism may be incorporated into a large variety of adjustable beds. 
   In the preferred form, the axis displacement mechanism comprises two sliding telescopic mechanisms on opposite lateral sides of the bed. The outer portions of the telescopic mechanism, which act as guides, are bound to the bed&#39;s chassis. The inner bars of the telescopic mechanism are rotatably connected to the torso-supporting section of the bed. 
   In one embodiment, the axis displacement mechanism is actuated by a traction cable system. A steel cable is affixed at its ends to the bed&#39;s chassis. The cable is mounted on pulleys placed on selected points of the axis displacement mechanism and on the structure of the torso-supporting section, defining a circuit. When the torso surface is elevated, it forces traction of the flexible steel cable, forcing the inner bars of the telescopic mechanisms into extension, which in turn translates the torso rotational axis in the headboard direction. One or more traction springs bias the axis displacement mechanism toward the retracted position, so that the torso rotational axis will translate back to its original position as the torso surface is lowered. By regulating the length and amount of slack in the cable, one can preset an initiation angle at which the torso rotational axis begins to be forced backed. In this embodiment, the relative position of the torso rotational axis is a function of the elevation angle of the torso surface. 
   In another embodiment, one or more electric or hydraulic actuators are provided to act on the sliding telescopic mechanisms. In such an embodiment, the actuator regulates the extension and retraction of the torso rotational axis independently of the elevation angle of the torso surface. 
   It is the inventors&#39; intent that the scope of any of the claims be defined by the language of the claims, and not narrowed by reference to the preferred embodiments described in this summary or in the detailed description of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates one embodiment of a simple adjustable bed having a traction-wire-based sliding torso section subframe in a retracted position. 
       FIG. 2  illustrates the adjustable bed of  FIG. 1  in a partially inclined position, with the bed&#39;s sliding torso section subframe in a partially extended position. 
       FIG. 3  illustrates the adjustable bed of  FIG. 1  in a significantly inclined position. 
       FIG. 4  illustrates an alternative embodiment of an adjustable bed having a rack-and-pinion-based sliding torso section subframe in a retracted position. 
       FIG. 5  illustrates the adjustable bed of  FIG. 4  in a partially inclined position, with the bed&#39;s sliding torso section subframe in a partially extended position. 
       FIG. 6  illustrates the adjustable bed of  FIG. 4  in a significantly inclined position. 
       FIG. 7  illustrates a patient support structure with one embodiment of a traction-wire based sliding subframe. 
       FIG. 8  illustrates the patient support structure of  FIG. 7  with the torso section in a partially inclined position. 
       FIG. 9  is a from-the-side perspective view of the patient support structure of  FIG. 7  with the torso section in a significantly inclined position. 
       FIG. 10  illustrates the patient support structure of  FIG. 9  from an oblique perspective. 
       FIG. 11  illustrates the patient support structure of  FIG. 8  from an oblique perspective. 
       FIG. 12  illustrates the patient support structure of  FIG. 7  from an oblique perspective. 
       FIG. 13  illustrates another, more sophisticated embodiment of a patient support structure with a sliding torso section subframe. 
       FIG. 14  illustrates an adjustable bed with a sliding torso section subframe. 
       FIG. 15  illustrates the patient support structure of  FIG. 7  with a cable slack adjustment mechanism. 
       FIG. 16  illustrates a patient support structure having a rack-and-pinion-based sliding torso section subframe with a motorized actuator for driving the gearwheels. 
   

   DETAILED DESCRIPTION 
   In describing preferred and alternate embodiments of the technology described herein, as illustrated in  FIGS. 1-16 , specific terminology is employed for the sake of clarity. The technology described herein, however, is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish similar functions. 
     FIGS. 1-16  illustrate perspective views of different embodiments of an adjustable, articulatable bed  10  that extends along a longitudinal dimension  16  between a head end  12  and a foot end  14 . To more fully illustrate the axis-displacement mechanism  120  of the bed  10 , the patient support surface, head board, side board, and other aspects of the bed  10  are not shown in  FIGS. 1-13 . 
   The adjustable bed  10  comprises an articulatable, multi-sectioned patient support structure  30 . The patient support structure  30  includes an articulating torso-supporting section  40 , a derriere-supporting section  50 , and preferably also an articulating upper-leg support structure  33  and an articulating lower-leg supporting structure  34 . The derriere-supporting section  50  may also articulate, but for simplicity,  FIGS. 1-16  depict embodiments with a derriere-supporting section  50  designed for rigid attachment to the main bed frame (not shown). Also for simplicity,  FIGS. 7-12  and  15 - 16  depict only the torso and derriere-supporting sections  40  and  50  of the patient support structure  30 . 
   To reduce compression of the lumbo-sacral area during articulation, the lower portion of the torso-supporting section  40  slides back as the torso-supporting section  40  is articulated toward an inclined position. The torso-supporting section  40  rotates about a transversal axis of rotation  110 . As the torso-supporting section  40  rotates from a level ( FIGS. 7 ,  13 ) or substantially level position  42  (e.g.,  FIG. 1 ) to an inclined position  44  (e.g.,  FIGS. 2 ,  3 ), an axis-displacement mechanism  120  causes the transversal axis of rotation  110  to slide back, along the bed&#39;s longitudinal dimension  16 , toward the bed&#39;s head end  12 . As the torso-supporting section  40  rotates from an inclined position  44  to a level position  42 , the axis-displacement mechanism  120  causes the transversal axis of rotation  110  to slide forward, toward the bed&#39;s foot end  14 . 
   The axis-displacement mechanism  120  comprises a sliding subframe  130  mounted on a guide mechanism  140   a ,  140   b . The sliding subframe  130  comprises two parallel sliding arms or bars  132 ,  134  supporting and rotatably joined to the torso-supporting section  40  via hinges  112 , which define the transversal axis of rotation  110 . The guide mechanism, which is mounted on or adjacent to the derriere-supporting section  50 , comprises two guides  140   a ,  140   b  positioned on opposite lateral sides of the derriere-supporting section  50 . These guides  140   a  and  140   b  are adapted to guide the sliding arms or bars  132 ,  134  of the sliding subframe  130  between a retracted position  142  and an extended position  144  along the bed&#39;s longitudinal dimension  16 , thereby translating the transversal axis of rotation  110  along the longitudinal dimension  16 . The fully retracted and fully extended positions  142  and  144  of the sliding subframe  130  define opposite limits of translation of the transversal axis of rotation  110 . 
     FIGS. 1-3  illustrate a traction-cable-based embodiment of the axis-displacement mechanism  120 . Each end of a long traction cable  160  is fixedly attached to opposite sides of the bed  10  in the region of the derriere-supporting section  50 . The traction cable  160  is mounted along intermediate points of its length on several pulleys  165  positioned on the sliding frame and the torso-supporting section  40 . Articulation of the torso-supporting section  40  toward the inclined position  44  tensions the traction cable  160 , which in turn pushes the sliding bars  132 ,  134  from their retracted positions  142  toward their extended positions  144 . Although a single long traction cable  160  is preferred, two separate traction cables  160  can replace the single long traction cable  160  depicted in  FIGS. 1-3 . At least one, and preferably two traction springs  170  are provided to bias the sliding bars  132 ,  134  toward their retracted positions  142 . In this manner, the bars  132 ,  134  return to their retracted positions  142  as the torso-supporting section  40  articulates from the inclined position  44  back toward the substantially level position  42 . 
   In preferred embodiments, the axis-displacement mechanism  120  is adapted to initiate translation of the transversal axis of rotation  110  toward the head end  12  of the bed  10  when the torso-supporting section  40  reaches a preset initiation angle  116  ( FIG. 2 ) of twenty-five degrees or more. For this purpose, a cable-slack adjustment mechanism  168  ( FIG. 15 ) (such as a clamp or screw) is provided to regulate the length and amount of slack in the traction cable  160 . More particularly,  FIG. 15  illustrates a leadscrew  171  that moves a leadscrew nut  172  along the screw axis. The leadscrew nut is connected to an eyehook (not shown) through which the cable  160  is threaded between two of the pulleys  165 . Movement of the leadscrew  171  controls the amount of slack by drawing the cable  160  away from or toward the segment connecting the adjacent pulleys  165 . The amount of slack in the cable  160  regulates the initiation angle  116  for initiating translation of the transversal axis of rotation  110 . 
     FIGS. 4-6  illustrate a rack-and-pinion-based embodiment of the axis-displacement mechanism  120 . In this embodiment, rack and pinion mechanisms  190  are positioned on opposite lateral sides of the derriere-supporting section  50 . Each rack and pinion mechanism  190  comprises a gearwheel  192  mounted on the sliding subframe  130  that engages teeth  196  on the derriere-supporting section  50 . Sliding arms  132  and  134  of the sliding subframe  130  are, as in  FIGS. 1-3 , adapted to move between retracted and extended positions within guides  140   a ,  140   b  mounted on the derriere-supporting section  50 . 
   In a typical embodiment, one or more electrically-powered mechanical actuators  46  ( FIGS. 8 ,  16 ) will articulate the torso-supporting section  40  between its the level and inclined positions  42  and  44 . In  FIGS. 1-3 , this machine-powered articulation in turn causes translation of the sliding subframe  130  and displacement of the axis of rotation  110  without the use of any additional mechanical actuators. Likewise, in  FIGS. 4-6 , this machine-powered articulation causes the gearwheels  192 , which are linked to the torso-supporting section  40  via linkages  198 , to rotate, which in turn causes translation of the sliding subframe  130  and displacement of the axis of rotation  110  without the use of any additional mechanical actuators.  FIG. 16  depicts an alternative embodiment. Here, the displacement of the axis of rotation  110  would be effected by one or more additional motorized actuators  180  ( FIG. 16 ) mounted to the adjustable bed  10  to drive the gearwheels  192 , which in turn drives the sliding frame  130  between its retracted and extended positions  142  and  144 . 
     FIGS. 13 and 14  illustrate an embodiment of the sliding subframe mechanism incorporated into a mechanical bed of the type described and depicted in application Ser. No. 11/869,696 entitled “Bed with Adjustable Patient Support Framework” filed on Oct. 9, 2007, which application is herein incorporated by reference. In particular, an adjustable bed  10  is depicted having a patient support surface  20 , a torso-supporting section  40  with a torso support litter  68  and an axis-displacement mechanism  120  for the torso-supporting section  40 . But it should be understood that the invention is not so limited, unless explicitly so limited by the claims, and can be incorporated in a large variety of hospital and non-hospital beds. 
   This specification also incorporates by reference the following disclosures filed as part of the Patent and Trademark Office&#39;s Document Disclosure Program: the disclosure by Eduardo R. Benzo and Rodolfo W. Ferraresi entitled Levita-Bed System, filed on Dec. 12, 2005, and assigned document number 592241; the disclosure by Eduardo R. Benzo, Rodolfo W. Ferraresi, and Mario C. Eleonori entitled Dynamic Multipositional Hospital Bed, filed on Feb. 15, 2006, and assigned document number 596795; the disclosure by Eduardo R. Benzo, Rodolfo W. Ferraresi, and Mario C. Eleonori entitled Dynamic Multipositional Hospital Bed, filed on Jul. 6, 2006, and assigned document number 603707; the disclosure by Eduardo R. Benzo, Rodolfo W. Ferraresi, and Mario C. Eleonori entitled Use and Control Methods for Multipositional Beds, filed on May 12, 2006, and assigned document number 610034; and the disclosure by Eduardo R. Benzo, Rodolfo W. Ferraresi, and Mario C. Eleonori entitled System for Virtual Communication between Patient and the Rest, filed on Dec. 5, 2006, and assigned document number 610042. 
   This invention also incorporates herein by reference, the following patent applications: App. No. 60/979,836 entitled “Patient Support Surface with Modulating Hip-Cradling Perimeter” filed on Oct. 14, 2007; App. No. 60/979,837 entitled “Adjustable Bed with Sacral Pressure Relieve Function” filed on Oct. 14, 2007; and App. No. 60/979,838 entitled “Modulating Support Surface to Aid Patient Entry and Exit” filed on Oct. 14, 2007. 
   Having thus described exemplary embodiments of the present invention, it should be noted that the disclosures contained in  FIGS. 1-16  are exemplary only, and that various other alternatives, adaptations, and modifications may be made within the scope of the present invention. Accordingly, the present invention is not limited to the specific embodiments illustrated herein, but is limited only by the following claims.