Abstract:
The disclosed adjustable backrest provides a plurality of generally horizontal straps arranged from the top to the bottom of the rigid back shell to provide anterior to posterior support and comfort for a patient. Generally speaking, the generally horizontal straps provide variably adjustable tension straps that allow for precise positioning of the patient to reduce or remove pressure points from the patient&#39;s thoracic to sacrum region.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation application of U.S. patent application Ser. No. 14/629,202, filed on Feb. 23, 2015, and entitled Adjustable Backrest (as amended), which claims priority to U.S. Provisional Patent Application No. 61/977,498, filed on Apr. 9, 2014, and entitled Backrest, the entire contents of these applications is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The disclosure herein relates generally to an improved backrest designed to safely position and accommodate spinal deformities presented throughout the wheelchair user population. More specifically, the disclosure relates to a new backrest that safely positions and accommodates most known spinal deformities through a range of anterior to posterior adjustments made within the system itself. 
       BACKGROUND OF THE INVENTION 
       [0003]    Seating and positioning technologies are primarily directed to four main areas of concern, namely, posture, skin integrity, function and patient comfort. Posture generally refers to the support and accommodation of various spinal deformities such as kyphosis, lordosis and scoliosis. Kyphosis is an exaggeration of the curving of the spine that causes a bowing or rounding of the back, which leads to a hunchback or slouching posture. Lordosis refers to an exaggeration of the inward curve of the lumbar spine. Other postural defects observed in the patient population include but are not limited to the loss of normal lumbar curve, rounded shoulders, thoracic kyphosis and lower cervical fluxion with upper cervical extension. 
         [0004]    Skin integrity is another important concern. Individuals Who spend a significant amount of time in wheelchairs can develop skin conditions caused by pressure or shear between the skin and the point of contact to the wheelchair. 
         [0005]    Function relates to the mobility and motion provided to the wheelchair user using the various seating and positioning products. The industry classifies this patient capability through the definition of Activities of Daily Living (ADL). ADL is a term used in healthcare to describe routine activities that people tend do every day without needing assistance. There are some basic ADLs which include: eating, dressing, mobility and toileting. The claimed backrest helps promote these necessary functions through proper support and uniform pressure over the given area while avoiding limitations to a user&#39;s range of motion to perform these ADLs. 
         [0006]    Finally, patient comfort is of utmost concern for individuals who must use a wheelchair for long periods of time. The claimed invention provides several areas of adjustability as well as a wide range of adjustability within a given area of the backrest. The claimed invention is designed to be able to accommodate all of the above-mentioned seating and positioning needs thereby increasing users&#39; overall mobility and lessening users&#39; potential for injuries. 
       SUMMARY OF THE INVENTION 
       [0007]    The claimed invention provides a backrest with a reinforced frame such that a large center portion of the chair back is open so as to allow for spinal deformities to protrude through the aperture. The claimed invention provides for various adjustable tensioning mechanisms to support certain spinal deformities. Although variable for specific conditions, the claimed invention provides an aperture that begins approximately above the posterior superior iliac spine of a patient and may, at its highest point, be no higher than their acromion process. 
         [0008]    The claimed invention permits anterior and posterior adjustments in the backrest to reduce the pressure over a given area. The claimed invention further permits its main support surface, the backrest, to be infinitely variable to the patients complementing support needs within its field of adjustment. The claimed inventions ability to compliment and support the varying patient shapes is what increases the patient contact area thus lowering the overall pressure applied per square inch. This reduction in pressure per square inch to the patients skin directly decreases the risk for skin tissue breakdown. 
         [0009]    The invention further provides a plurality of generally horizontal straps arranged from the top to the bottom of the rigid back shell to provide additional anterior to posterior support and comfort for a patient. It would be additionally desirable to provide variably adjustable and horizontally mounted tension adjustable straps that would allow for precise positioning of the patient to reduce or remove pressure points from the patient&#39;s thoracic to sacrum region. It would be further advantageous to provide a design wherein it is possible to adjust the tension of the strap while the patient full weight is seated against the backrest. 
         [0010]    The claimed invention is extremely useful in treating conditions such as lordosis, kyphosis and scoliosis because of its flexibility of use in the coronal and sagittal planes, although it can be used to treat other conditions. For example, the claimed inventions is very well suited to provide support to a person with Lordosis because it allows protrusion of the upper thoracic region through the shell of the backrest in the sagittal plane. The adjustable tension mechanism of the claimed invention allows the back to maintain uniform support across the back of the user to support the lordosis without creating pressure spots. Likewise, the claimed is also useful in treating defects in the coronal-sagittal plane such as scoliosis. Scoliotic patients frequently require some corrective pressure to one side or another of the spine. The adjustable tension mechanism of the claimed invention allows a section of the backrest to be set to a specific corrective pressure to support scoliotic protrusions. 
         [0011]    Of course, it would be advantageous to provide a backrest in a variety of widths and heights to fit people of all shapes and sizes. It would be further advantageous to provide a backrest that can be used with lateral pads to both position a user and to support the user. It would also be advantageous to provide a backrest that can be used with existing single point and multipoint mounting systems and with all types of existing wheelchairs. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  shows a side and rear perspective view of the claimed backrest with a cover installed over the claimed backrest, the backrest being installed on a wheelchair. 
           [0013]      FIG. 2  shows a rear devotional view of the claimed backrest without a backrest cover attached to the canes of a wheelchair showing one type of tension adjustment mechanism. 
           [0014]      FIG. 3  shows a front elevational view of the claimed backrest with the backrest cover removed. 
           [0015]      FIG. 4  shows a side and back exploded perspective view of one type of installation bracket that can be used with the claimed backrest. 
           [0016]      FIG. 5  is a rear elevational view of the backrest showing two alternative configurations of the backrest. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Now, referring to the drawings in detail, wherein like reference numbers refer to like elements throughout,  FIG. 1  shows the claimed backrest  11  installed on the upright supports or canes  3  of a wheelchair  1 . The backrest  11  can be installed on the canes  3  of a wheelchair using any of a plurality of conventional wheelchair back mounting brackets  7 , such as the two point mounting bracket system shown in  FIG. 1 . The backrest  11  can also be installed using a single point mounting system as shown in  FIG. 3 . 
         [0018]    Referring now to  FIG. 2 , the backrest  11  is comprised of a rigid perimeter frame  21  having a large central aperture  23 , a top portion  24 , a bottom portion  25  and a pair of substantially identical sides  26 . Sides  26  provide attachment means for a plurality of fixed straps  31 , which extend from both sides  26  of the backrest  11 . Possible attachment means for the plurality of fixed straps  31  include apertures, grommets and hooks as well as other fixed and removable attachment means. Fixed straps  31 , in at least one embodiment, serve as attachment points for variably adjustable tension straps  41 , but are not necessary to the claimed invention. Variably adjustable tension straps  41  are arranged between the fixed straps  26 . 
         [0019]    The claimed invention could include several variably adjustable straps  41 . For example, in the embodiment shown in  FIG. 3 , four variably adjustable straps  41  are used. Thus, the embodiment shown can provide adjustment in four areas along the vertical aspect of the backrest. Alternate embodiments using either more or fewer variably adjustable straps  41  are within the scope of the invention in that certain condition might require either more adjustability or less adjustability. 
         [0020]    Variably adjustable straps  41  can preferably be tensioned and eased without moving the person seated against the backrest  11  via tensioning mechanism  51 . One embodiment of the invention calls for variably adjustable straps  41  that can be an inelastic cord or cable that is securable at a tension but can be further tensioned or eased off, if necessary. An additional embodiment could employ hook and loop style fasteners that can be pulled through a loop or buckle, doubled back over and secured to itself. Likewise, other tensioning mechanisms  51  could be used including, but not limited to ratchet tensioners, reel tensioners, screw tensioners, cable tensioners and spring tensioners, all of said tensioning mechanism being designed maintain a desired fit to the backrest, allow easy adjustment, be adjustable in small increments, have a high degree stability once adjusted and be at least somewhat resistant to moisture and other elements. 
         [0021]    Referring again to the particular embodiment of the invention shown in  FIG. 3 , which shows four separately adjustable support structures  45 , each of said adjustable support structures  45  having an adjustable tensioning mechanism  51  to control one section of the backrest  11 . Obviously, more or fewer support structures  45  could be used. Moreover, as shown on  FIG. 3 , there are eight fixed straps  31  on each side  26  of the backrest  11 . It is possible to employ more fixed straps  31  and additional adjustable tension mechanisms  51  so as to add adjustable support structures  45  which are each individually adjustable to the backrest  11 . 
         [0022]    In the claimed embodiment shown in  FIG. 3 , each of the adjustable tension mechanisms  51  is attached to two fixed straps  31 . Cable  41  is wound through loop buckles  33 , or  81  (shown in  FIG. 5 ), or around guide members or the like which are attached to fixed straps  31  opposite the adjustable tension mechanisms  51 . It is preferable to provide guide members or loop buckles  33 ,  81  or the like that offer relatively little friction to cable  41  so that cable  41  tension remains uniform throughout the length of the cable  41 . It is even more preferable to provide low friction guide members  33 . Additionally, adjustable tension mechanism  51  could be attached to only a single fixed strap  31 . Thus, in the embodiment shown, each pair of fixed straps  31  would be connected by a cable  41  tensioned by an adjustable tension mechanism  51 . Likewise, the cable  41  of the claimed invention is not limited to standard round cross-section cable, but could include flat straps and other types of connecting means. 
         [0023]    In an additional embodiment, the fixed straps  31  are not used and the adjustable tension mechanism  51  is attached to one side  26  of the backrest  11  and cable  41  is attached to the opposite side of the backrest  11  via low friction guide members  33 . As in the case of the embodiment using the fixed straps  31 , it is possible to use as many or as few adjustable tension mechanisms  51  as is desired. 
         [0024]    As shown in  FIG. 3 , adjustable tension member  51  may further include a guide member  55 . Guide member  55  essentially provides a path for cable  41  such that cable  41  can he doubled over so as to serve a broader area of the backrest  11  as shown in  FIG. 3 . Thus, cable guide member  55  is helpful to create a larger section under the control of a single adjustable tension member  51 . 
         [0025]    For example, as shown in  FIG. 2 , adjustable tension member  51  is attached to one side of the rigid backrest frame  21  by fixed straps  31 . Opposite the adjustable tension member  51  are a pair of guide members  33 . As shown in  FIG. 2 , the cable runs from the adjustable tension mechanism to the first guide member  33  attached to the first side of the rigid backrest frame  21 , around the cable guide  55  on the adjustable tension member  51  and then around the second guide member  33  attached to the first side of the frame and then back to the adjustable tension mechanism. 
         [0026]    Preferably, and as shown in  FIG. 1 , the front of the backrest  11  is covered by a cover  61  that may or may not include additional cushioning. Additional lateral supports (not shown) attachable to the backrest for further positioning needs. 
         [0027]      FIG. 5  shows two additional embodiments of the claimed invention. Specifically,  FIG. 5  shows five (5) adjustable support structures  45 . The upper two (2) adjustable support structures  45  are identical to those disclosed elsewhere in this detailed description. The lower two (2) support structures  45 , while similar in function, are slightly different in appearance. Specifically, instead of a cable  41  that stretches across the backrest  11  to the opposite side of the backrest, flat straps  83  are tensioned across backrest using an adjustable tension member  51 . 
         [0028]    The middle adjustable support structure  45  shown in  FIG. 5  is a single strap  83  support structure. Instead of using the single strap  83  as shown, the adjustable support structure  45  might also employ a cable  41  that stretches across the backrest as shown in the above embodiments. 
         [0029]    As discussed above, the claimed invention is particularly well-suited for patients with lordosis and scoliosis in that it is adjustable along the height of the backrest to provide uniform corrective pressure to aid in treating postural defects and deformities. 
         [0030]    While the present invention has been described in terms of preferred embodiments, it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.