Abstract:
An apparatus convertible to a chair or table comprises a support structure; first and second pairs of wheels rotatably supporting the support structure; and a platform supported by the support structure. The platform includes a seat support and a back support. The platform is positionable between a chair configuration and a table configuration. The first pair of wheels have inboard and outboard positions. The first pair of wheels are in the inboard position when the platform is in the table configuration. The first pair of wheels are in the outboard position when the platform is in the chair configuration.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to an apparatus convertible to a chair or treatment table. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an apparatus convertible to a chair or treatment table that expands its footprint when in the chair configuration to account for shift in the center of gravity of the patient when seated up. 
     It is another object of the present invention to provide an apparatus convertible to a chair or treatment table that moves the patient to a rearward position when seated up to shift the center of gravity of the patient toward the center of the apparatus. 
     It is another object of the present invention to provide a split cushion that can be easily removed from underneath a patient lying on a treatment table to expose the underlying firm surface of the table for a medical procedure, such as a CPR. 
     In summary, the present invention provides an apparatus convertible to a chair or treatment table comprising a support structure; first and second pairs of wheels rotatably supporting the support structure; and a platform supported by the support structure. The platform includes a seat support and a back support. The platform is positionable between a chair configuration and a table configuration. The first pair of wheels have inboard and outboard positions. The first pair of wheels are in the inboard position when the platform is in the table configuration and are in the outboard position when the platform is in the chair configuration. 
     These and other objects of the present invention will become apparent from the following detailed description. 
    
    
     BRIEF DESCRIPTIONS OF THE DRAWINGS 
     FIG. 1 is a perspective view of an apparatus made in accordance with the present invention. The apparatus is convertible to a chair or treatment table and is shown in a table configuration. 
     FIG. 2 is a perspective view of the apparatus of FIG. 1, shown in a chair configuration. 
     FIG. 3 is a partial perspective view of an opposite side of FIG.  1 . 
     FIG. 4 is a right side elevational view of FIG.  1 . 
     FIG. 5 is a left side elevational view of FIG.  2 . 
     FIG. 6 is a perspective view of a split cushion used in the present invention. 
     FIG. 7 is a fragmentary perspective view of a cylinder connected to a stationary frame member and a sliding rail, shown extended when the apparatus is in the chair configuration. 
     FIG. 8 is a schematic view of a closed loop system used to spread out or draw in the front wheels of the apparatus. 
     FIG. 9 is a fragmentary perspective view of a linkage mechanism used to move a sliding frame relative to a stationary frame. 
     FIG. 10 a  is cross-section view taken along line  10 — 10  of FIG.  4 . 
     FIG. 11 is a schematic perspective view of a hydraulic system used to raise or lower the platform structure of FIG. 1 
     FIG. 12 is a schematic perspective view of a closed loop system used to raise or lower the back support of the apparatus of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An apparatus R convertible to a chair or treatment table is disclosed in FIG.  1 . The apparatus R includes a support structure  2  movably supported by a front pair of wheel assemblies  4  and a rear pair of wheel assemblies  6 . A platform structure  8  is supported by the support structure  2 . 
     The platform structure  8  has a table configuration for supporting a patient in a substantially horizontal position, as best shown in FIG. 1, or a chair configuration for supporting a patient in a seated position, as best shown in FIG.  2 . When the platform structure  8  is in the table configuration, the front wheel assemblies  4  are drawn inwardly towards each other. When the platform structure  8  is in the chair configuration, the wheel assemblies  4  are drawn apart from each other to provide a wider footprint, as best shown in FIG.  2 . In addition, the platform structure  8  moves towards the rear when in the chair configuration to position the weight of the patient towards the center of the support structure  2 . 
     The support structure  2  comprises a base support  10  and upper support  12  interconnected together by a pair of double-acting cylinders  14 , which may be hydraulic or pneumatic. The cylinders may be replaced by substitutes well known in the art, such as motor operated screws. The cylinders  14  are used to raise or lower the upper support  12  when both the cylinders  14  are operated at the same time. The cylinders  14  are also used to tilt the upper support  12  forwardly or backwardly by selectively operating one of the cylinders  14  independently of the other cylinder in a manner well known to a person skilled in the art. For example, if the cylinder  14  nearer the rear wheel assemblies  6  is displaced more than the cylinder  14  nearer the wheel assemblies  4 , either downwardly or upwardly, the rear portion of the upper support  12  will either move upwardly or downwardly more than the front portion would move, thereby inclining the upper support  12  (and the platform structure  8  attached thereto) in one direction or the other direction. Control levers  16  operably connected to respective cylinders  14  in a conventional manner provide the means for selectively operating the cylinders  14 . A foot pedal  18  (see FIG. 3) is provided for simultaneous operation of the cylinders  14 . The pedal  18  is connected to the cylinder circuit in a manner well known to a person skilled in the art. A pump  20  operably connected to the foot pedal  18  is provided to power the cylinders  14 . 
     The base support  10  may be made in any conventional manner. For example, the base support  10  may include a solid plate member  22  joined to a frame structure  24 . 
     The upper support  12  comprises a pair of parallel members  26  interconnected together by a pair of transverse members  28 , which are in turn respectively secured to respective cylinders  14 . Rollers  30  fixed to the members  26  support a pair of rails  29  in a sliding manner and are used to support the platform structure  8  in a manner that will be described below. 
     The front wheel assemblies  4  are pivotably connected to the base support  10 , as best shown in FIG.  1 . Each wheel assembly  4  includes an outwardly extending arm  32 , one end of which is connected to a swivel wheel  34  and the other end of which is connected to a pivot rod  36  supported by roller bearings within housing  38 . A linkage arm  40  is fixedly secured to respective pivot rod  36  and pivotally connected to a double-acting cylinder  42 . Hydraulic lines  44  are operably connected in a conventional manner to a double-acting cylinder  45  (see FIG. 7) which is actuated by the lifting of a back support  48  of the platform structure  8  to an upright position. The cylinders  42  and  45  are connected together in a closed loop (see FIG. 8) and are coordinated with each other such that the cylinder  42  is extended, as best shown in FIG. 1, to bring the wheel assemblies  4  inwardly, when the cylinder  45  is retracted (when the back support  48  is manually brought to a substantially horizontal position). The cylinder  42  is retracted to spread the wheel assemblies  4  apart, as best shown in FIG. 2, when the cylinder  45  is extended (when the back support  48  is manually brought to an upright position). 
     In addition to the back support  48 , the platform structure  8  also includes a seat support  50  and a leg support  52  hingeably connected to the rails  29  in a manner as will be described below such that the platform support  8  can be positioned in a table configuration, as best shown in FIG. 1, or a chair configuration, as best shown in FIG.  2 . 
     Referring to FIG. 4, the back support  48  includes an underlying board  54  supporting a split cushion  56 . The board  54  is pivotably connected by a pair of brackets  58  which are in turn secured to the rails  29 . The cylinders  46  are pivotably connected to the back board and to the rails  29 . A pair of brackets  64  further connect the back board  54  to a linkage mechanism  66  that provides for the lowering of the leg support  52  to a substantially upright position when the back support  48  is raised to the upright position and to pull the seat support  50  rearwardly toward the center of the support structure when in the chair configuration. 
     The seat support  50  includes a cushion  68  supported by an underlying frame  70 , which in turn is operably secured to the sliding rails  29 . 
     The leg support  52  includes a cushion  72  supported by an underlying frame  74 . A frame  76  is pivotably connected to the frame  74  and is in turn pivotably connected to the sliding rails  29  and to a pair of linkage arms  78 . 
     The brackets  64  are connected to a pair of linkage arms  80 , which are in turn pivotably connected to a pair linkage arms  82 , and which are in turn connected to pair of linkage arms  83 . The linkage arms  82  are pivotally connected at their intermediate portions to the sliding rails  29  at pivots  85 . The other ends of the linkage arms  83  are pivotally connected to the stationary members  26  at pivots  87 . 
     The linkage mechanism  66 , as can be seen in FIG. 9, comprises the interconnected linkage arms  76 ,  78 ,  80 ,  82  and  83  and is effective to lower the leg support  52  in an upright position when the back support  48  is raised in the upright position. In addition, the linkage mechanism  66  pulls the seat support  50  towards the center of the support structure when the apparatus is changed to the chair configuration. Referring to FIGS. 4 and 5, when the back support is raised to the upright position, the distance between the pivots  85  and  87  increases, thereby causing the rails  29 , which carry the seat support  50  (and the back support  48  and leg support  52 ), to move towards the rear. 
     Referring to FIG. 6, the split cushion  56  comprises cushion members  84  and  86  removably secured to each other along longitudinal sidewalls  88  by means of hook and loop fastener  90  or other standard means. The split cushions  56  are provided with handles  92  so that when the split cushions are desired to be separated from each other, a user on each side of the cushion can conveniently grab the handles  62  and pull in opposite directions. The split cushion  56  is advantageously used in a situation where a patient, lying in a horizontal position, requires a medical procedure, such as CPR, wherein a firm support is required underneath the patient. In such a case, the split cushion  56  is easily pulled from underneath the patient&#39;s upper body by grabbing the handles  92  and pulling in opposite directions, thereby exposing the backboard  54  to firmly support the upper body of the patient. 
     Referring to FIG. 7, the cylinder  45  is secured to stationary member  26  at pivot  94  and to sliding rail  29  at pivot  96 . Sliding motion of the rail  29  relative to the rail  26  will cause the cylinder  45  to extend or retract, causing the front wheel cylinder  42  to retract or extend, respectively. The cylinder  45  is shown extended in FIG.  7 . 
     Referring to FIG. 9, sliding motion of the rails  29  relative to the fixed members  26  is caused by the folding or unfolding of the linkage mechanism  66  when the back support  48  is raised manually to an upright position or lowered to a horizontal position. Referring to FIG. 4, the linkage mechanism  66  is shown in the folded position where the distance between the pivots  85  and  87  is smaller than when the linkage mechanism  66  is in the unfolded position, as shown in FIGS. 5 and 9. 
     Referring to FIG. 10, the front cylinder  14  is connected to the front cross-member  28  with a swivel connector  98  and to the plate member  22  with a stationary, non-swiveling connector  100 . Referring to FIGS. 2 and 11, the rear cylinder  14  is connected to the rear cross-member  28  and to the plate member  22  with swivel connectors  98  to permit differential lowering or raising of the front and rear portions of the platform structure  8 . 
     Referring to FIGS. 5 and 12, the cylinders  46  are connected in a closed loop through a valve  102 , which allows flow in both directions when open. Ends  104  are connected to the back support  48  with pivots  106 . The other ends  108  are connected to the rails  29  with pivots  110 . To raise the back support  48  from the horizontal to the upright position, the valve  102  is opened to allow the fluid within the cylinders  46  to flow to the other side of the cylinders to allow the piston rods to extend outwardly. When the valve  102  is closed, the back support  48  will remain in the upright position since the fluid within the cylinders would be prevented from flowing into the opposite ends of the cylinders. To lower the back support  48  to the horizontal position, the valve  102  is opened to allow the fluid to flow in the opposite direction. The cross-member  62  provides support to the back support  48  in the horizontal position. 
     Referring to FIGS. 4 and 5, the leg support  52  is hinged to the frame  76  at pivots  112 . The frame  76  is connected to the rails  29  with pivots  114 . When the apparatus is in the table configuration, the leg support  52  is substantially horizontal, as best shown in FIG. 4. A bracket  116  connected to the arm  78  pushes the leg support  52  to line up with the seat support  50 . When the apparatus is in the chair configuration, the leg support  52  is substantially vertical and an angled bracket  118  catches the edge of the frame  76  and prevents the leg support  52  from falling forward. 
     While this invention has been described as having preferred design, it is understood that it is capable of further modification, uses and/or adaptations following in general the principle of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains, and as may be applied to the essential features set forth, and fall within the scope of the invention or the limits of the appended claims.