Abstract:
Disclosed is a chair comprising a seat, a base, a pair of parallel spaced apart uprights extending from the base positioned to opposed sides of the spine of a user seated on the chair, the uprights supporting the seat and a body support member extending from each upright in opposed directions, said body support members being substantially parallel to the back of said user. Each body support members may integrally formed with an upright with have an arcuate portion therebetween. The chair may further comprise first and second pairs of body support members and be rotatable between first and second orientations in which either the first or second body support members may form the seat or back support for the user.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to chairs in general and in particular to a chair adapted to support and massage the back muscles of a user at one of a plurality of positions. 
     2. Description of Related Art 
     Chairs are common seating implements which commonly include a raised seating surface and a back rest or support. Chairs are used to support a user for working at a desk, table or the like or for relaxing. One common difficulty with conventional chairs is that their use may place stress or strain on the back of the user. 
     Stress or strain on the back of a user sitting in a chair may be due to the unnatural angles at which the back of the user is supported. Examples may be found in chairs that have backs which are too upright thereby forcing the user to support themselves at too steep of an angle of inclination or even vertically in some cases. 
     An additional source of stress or strain on the back of the user is due to the surface of the chair itself and the pressures it exerts upon the back of the user during use. In particular, many chairs include a hard surface. Such hard surfaces are known to cause pressure points leading to soreness and pain in the user. This is particularly the case the hard surface is rested against by the spine of the user. 
     Applicant is aware of previous attempts to provide a chair having a contact relieving portion in the middle of the back rest. Such attempts however have provided parallel panels which are rotatable or bend about a horizontal axis. In such devices however, the panels are often cantilevered from a bottom most portion and may therefore be prone to twisting about an axis parallel to the back of the user. Accordingly, such devices may upon application of pressure from the back of the user, be rotate about such an axis in a direction which reduces pressure of the panel on the muscles of the user adjacent to the spine. Examples of such devices may be found, in U.S. Pat. No. 5,577,811 to Ogg. 
     SUMMARY OF THE INVENTION 
     According to a first embodiment of the present invention there is disclosed a chair comprising a seat, a base, a pair of parallel spaced apart uprights extending from the base positioned to opposed sides of the spine of a user seated on the chair, the uprights supporting the seat and a body support member extending from each upright in opposed directions, the body support members being substantially parallel to the back of the user. 
     Each body support member may extend from the upright to a free distal end. Each body support member may be substantially planar. Each body support member may integrally formed with the upright. 
     Each body support member and upright may have an arcuate portion therebetween. The arcuate portion may have a radius of curvature of between 0.4 and 2.4 inches at a surface which supports a user. 
     The uprights may comprise vertical plates. The chair may further comprise first and second pairs of body support members. The first pair of body support members may form a seat portion and the second pair of body support members may form a back support for the user. 
     The uprights and first and second body support members may be rotatable between first and second orientations. In the first orientation the first body support member forms a seat and the second body support members form the back of the chair. In the second orientation the second body support members form a seat and the first body support members form the back of the chair. 
     The first and second body supports may have an angle of 100 degrees therebetween. The base may comprise planar members oriented perpendicularly to the uprights. The base may comprise a first set of legs for supporting the chair in the first orientation and a second set of legs for supporting the chair in the second orientation. 
     Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In drawings which illustrate embodiments of the invention wherein similar characters of reference denote corresponding parts in each view, 
         FIG. 1  is a perspective view of a chair according to a first embodiment of the present invention. 
         FIG. 2  is a side elevational view of the chair of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the chair of  FIG. 1  taken along the line  3 - 3 . 
         FIG. 4  is a front elevational view of the chair of  FIG. 1 . 
         FIG. 5  is a top plan view of the chair of  FIG. 1 . 
         FIG. 6  is a side elevational view of the chair of  FIG. 1  at a second orientation. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a chair according to a first embodiment of the invention is shown generally at  10 . The chair  10  comprises and a pair of parallel spaced apart uprights  12  supporting seat and back portions,  20  and  30 , respectively and a base  50  supporting the uprights. 
     The uprights  12  are formed of substantially planar members having an outline  14 . As illustrated, the uprights  12  may have an egg-shaped curved outline  14 , although it will be appreciated that other outline shapes may be useful as well, such as, by way of non-limiting example, circular, rectangular, triangular, polygonal, oval or irregular. The uprights  12  include a plurality of upright slots  16  therein for receiving base members  52  into as will be more fully described below. The uprights  12  are arranged in parallel spaced apart relation to each other having a gap distance generally indicated at  80  in  FIG. 3 . 
     The base  50  comprises a plurality of planar base members  52   a ,  52   b , and  52   c  extending perpendicularly from the uprights. With reference to the second base ember  52   b  by way of example, each base member  52   b  has a substantially planar outline extending between first and second ends,  56   b  and  58   b , respectively and includes a pair of base slots  60   b  extending into the first end  56   b . Each of the first and third base members  52   a  and  52   c  may include similar base slots for locating within a desired upright slot. The base slots  60   b  are sized and positioned such that the base slots and upright slots  16  intermesh so as to affix the planar member to the uprights. As illustrated in  FIGS. 4 and 5 , the base members  52   a ,  52   b  and  52   c  have a width that is less than the width of the seat and back portions  20  and  30 . Having a relatively narrow width base encourages the user to use their legs to maintain when seated in the chair  10  so as to maintain the hips of the user in a more natural position as opposed to crossed which can impart stresses to the hips and lower back. In particular, the width of the first and third base members  52   a  and  52   c  may be selected to be between 3.9 and 7.9 inches (100 and 200 mm) wide and the second base member  52   b  may be selected to have a width of between 7.9 and 15.7 inches (200 and 400 mm) so as to provide greater stability to the rear of the chair. 
     The uprights slots  16  of each upright  12  are aligned with each other such that a base member located therein will extend perpendicularly across both uprights. The upright slots  16  and base slots  60   b  may be sized so as to receive the corresponding upright or base member therein in a friction or interference fit thereby providing a rigid connection between the uprights and the base members. Optionally, one or more of the base members  52   a ,  52   b  or  52   c  may be secured into the uprights by means of a fastener, adhesive or by permanent means such as welding although it will be appreciated that the fastening means utilized to secure the second base member  52   b  may be removable so as to permit the second base member  52   b  to be moved between different upright slots  16  as described below for different positions. 
     As illustrated, the chair  10  may include at least three base members  52   a ,  52   b  and  52   c . A front base member  52   a , a middle base member  52   b  and a rear base member  52   c . The front and rear base members  52   a  and  52   c  may be affixed to the uprights  12  at fixed location whereas the middle base member  52   b  may be movable between one of a plurality of upright slots so as permit the chair to be oriented at first and second orientations as illustrated in  FIGS. 2 and 6  and further explained below. 
     With reference to  FIG. 3 , the back portion  30  is formed from a pair of substantially co-planar back members  32  or panels supported in cantilever fashion from a corresponding upright to a free distal end  34 . The back members  32  may be substantially rectangular in outline as illustrated in  FIG. 1 , although it will be appreciated that other outline shapes may be utilized as well depending upon the appearance desired by the user, such as by way of non-limiting example, oval, circular, triangular, heart shaped, or irregular. The back members  32  are illustrated as being substantially planar, however it will be appreciated that the back members may also be curved or include some contouring may be provided corresponding to the back of a user. 
     As illustrated in  FIG. 3 , each back portion  30  may be continuously formed with the uprights  12 . In such embodiments, the back portion  30  and upright may include a curved portion  36  therebetween having a radius of curvature at the surface that is to support the user indicated generally at  38 . The radius of curvature  38  may be varied as desired by a user from between 0.4 and 2.4 inches (10 and 60 mm) with a radius of between 1.2 and 2 inches (30 and 50 mm) being particularly useful. 
     As illustrated in  FIG. 1 , the seat portion  20  may also be formed from a pair of substantially co-planar seat members  22  or panels supported in cantilever fashion from a corresponding upright to a free distal end  24 . The seat members  22  may be substantially rectangular in outline as illustrated in  FIG. 1 , although it will be appreciated that other outline shapes may be utilized as well depending upon the appearance desired by the user, such as by way of non-limiting example, oval, circular, triangular, heart shaped, or irregular. The seat members  22  may be formed integrally with their corresponding upright at a curved portion  26  in a similar fashion to the back members  32  and described above with reference to  FIG. 3 . 
     Also as illustrated in  FIG. 3 , the uprights  12  include a spacing therebetween corresponding to a location of the user&#39;s spine generally indicated at  80 . In particular, the uprights may be spaced apart by a distance of between 0.4 and 3.2 inches (10 and 80 mm) as desired by a user and depending upon the radius of curvature so as to maintain the curved portions  36  to either side of the spine of a user. As illustrated, the spine gap  80  is positioned along a central axis of the chair so as to receive the spine of the user therein. In operation, a user sitting on the chair will be positioned such that their spine is received within the spine gap  80  so that no pressure is exerted directly upon their spine by the chair. Additionally, in such use, it will be observed that the curved portions  36  of the back members  32  are located to engage upon and massage the long muscles to either side of the spine of the user. In operation, a user sitting on the chair  10  will exert a force upon the back members  32 . This will cause each back member  32  to be deflected away from the back in a direction generally indicated at  82 . As the back members  32  are deflected away from the back of the user, the curved portion  36  will be maintained as the closest point of contact with the user&#39;s back thereby serving to maintaining the curved portion  36  in contact with the long muscles along the user&#39;s spine. 
     The chair  10  may be orientable to a plurality of positions so as to support a user in one of a plurality of seating positions. By way of example, as illustrated in  FIG. 2 , the chair may be orientable to a first orientation. In the first orientation, the seat members  22  are substantially horizontal to provide a seating surface for a user and the back members  32  are upright to as to provide a back support for the user. In such an orientation, the first and second base members  52   a  and  52   b  support the chair. Turning now to  FIG. 6 , a second orientation is illustrated in which the back members  32  are substantially horizontal so as to now provide a seating surface for a user and the seat members  22  are upright so as to provide a back support for the user. In such an orientation, the second and third base members  52   b  and  52   c  support the chair. It will be observed that the second base member  52   b  is utilized to support the chair  10  in either the first or second orientation. It will also be observed that in either the first or second orientation, the second base member  52   b  is located in a different upright slot  16 . Accordingly, during the course of repositioning the chair between first and second orientations, the second base member  52   b  may be moved to the appropriate upright slot for that orientation. 
     Each of the uprights  12  have first and second portions  70  and  72 , respectively. The first portions  70  are connected to the seat members  22  and the second portions  72  are connected to the back members  32 . As illustrated in  FIGS. 2 and 6 , the first portion  70  is sized to have a shorter height than the second portion  72 . Accordingly, when the chair is oriented to the second orientation as illustrated in  FIG. 6 , the back members  32  which in this orientation for a seating surface for a user will be spaced apart from a floor  8  or other ground surface by a distance that is greater than the seat members  22  are spaced apart from the floor  8  when the chair is oriented in a first position as illustrated in  FIG. 2 . By way of non-limiting example, in the second orientation, a leading edge of the back members  32  may be spaced apart from the floor by a distance of between 15.7 and 23.6 inches (400 and 600 mm). Similarly, the seat members  22  may be spaced apart from the floor by a distance of between 11.8 and 15.7 inches (300 and 400 mm). 
     In the first orientation, the seat members may be oriented relative to the floor  8  by a first tilt angle, generally indicated at  74  so as to angle the seat members  22  at a rearward incline so as to present a more relaxing seating position for the user. The first tilt angle  74  may be selected to be any angle desired by a user, such as by way of non-limiting example between 20 and 40 degrees with an angle of between 20 and 30 degrees being particularly useful. Similarly, in the second orientation, the back members  32  may be angled relative to the floor  8  when the chair is in the second orientation by a second tilt angle generally indicated at  76  as illustrated in  FIG. 6 . The second tilt angle  76  may be selected to be between 0 and 30 degrees with an angle of between 10 and 20 degrees being particularly useful. The seat members  22  and back members  32  have an opening, generally indicated at  78  therebetween. The opening angle  78  may be selected according to the preferences of a user, such as by way of non-limiting example 95 and 110 degrees, with an angle of 100 degrees being found to be particularly useful for maintaining good posture between the back and hips of the user. 
     In an optional embodiment the first and third base members  52   a  and  52   c  may be formed of a continuous member as illustrated in  FIG. 5 . Optionally, the first and third base members  52   a  and  52   c  may be permanently secured to the uprights in such an orientation. 
     The materials utilized to form the chair may be of any suitable type including, without limitation, metals, woods and plastics. Although the above materials are provided for example purposes only, it will be appreciated that many other materials may also be suitable. The materials utilized to form chair may also be of any color as desired by a user. 
     The chair may be formed by providing a planar sheet of material cut to the outline of the uprights  12  and the back and seat members  32  and  22 . The sheet of material may then be plastically deformed, such as by way of non-limiting example, thermoforming so as to bend the back and seat members  32  and  22  about the back and seat curved portions  36  and  46  until the back and seat member  32  and  22  are aligned perpendicularly to the uprights. In such forming processes, the material may be selected from formable material such as, by way of non-limiting example, polyvinyl chloride (PVC), polyethylene, (PE), polycarbonate, cellulose acetate, acrylonitrile butadiene styrene (ABS), or acrylic. In other methods of forming the chair, laminated wood, such as plywood by way of non-limiting example may be and formed by way of known wood forming methods. Optionally, the uprights, back and seat members may be cast or otherwise molded into the desired shape. 
     It will be appreciated that although the chair  10  is described above as being formed of substantially rigid and hard materials, the seat and back members  22  and  32  may also have a cushioning surface applied thereto or incorporated therein. Non-limiting examples of such cushioning surfaces includes, rubbers, foam rubber, leather, fabric and the like. 
     While specific embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only and not as limiting the invention as construed in accordance with the accompanying claims.