Patent Grant
8567863
In general, this invention relates to seating devices and methods, and somewhat more specifically to a mechanism and a method for orienting a back support upon which an upper thoracic area of a user reclines while the user is seated. Even more particularly, the present invention relates to new and improved apparatus and methods for positioning the back support to achieve the best support angle to balance the upper torso of the user without adversely affecting optimal pelvic support and alignment characteristics of the user. The present invention has particular benefits in achieving optimal and safe posture for a user who depends on a wheelchair for mobility.
A back support and a seat support should perform many important functions to provide the best benefit to a seated individual. The back and seat supports should be comfortable and encourage proper support for optimal posture and posture control for a considerable length of time. The back and seat supports should also create stability and a sense of secure confinement, thereby avoiding a feeling or tendency of falling or slipping out of the seating device. The security of confinement is particularly important to a wheelchair user. In addition, the back and seat supports should also enhance the functional capabilities of the wheelchair user by supporting independence in activities of daily living.
The seat support plays an important role in obtaining these benefits. The seat support must receive and distribute the weight of the user, while facilitating reasonable movement of the user. Because the seat support resists most of the user's weight, it should prevent and reduce the incidence of localized areas of discomfort and soreness, which in the case of wheelchair users can lead to pressure ulcers and skin shear force abrasions, created by prolonged sitting without adequate pressure relief. Pressure ulcers and shear abrasions can become a serious health problem for wheelchair users who must remain constantly in contact with the seat support.
There are a number of different support contours and configurations, as well as support theories and techniques, for configuring the contour of the seat support. One particularly advantageous configuration is described in U.S. Pat. No. 7,216,388, which is assigned to the assignee of this invention. However and regardless of the type of contour which may be employed, it is essential that the upper leg and pelvic skeletal structure and pelvic tissue of the user interact in a consistent intended way with the contour of seat support. Otherwise, the pelvic area of the user may move into an unintended position, causing distortion of the intended anatomical interaction with the contour of the seat support and diminishing or destroying the benefits desired from the seat support. This particular constraint is particularly critical for wheelchair users who often lack the capability to adjust or move their own position within the seat support and must depend entirely on the contour of the seat support and the back support to maintain the intended orientation and interaction.
The back support must function in conjunction with the seat support to maintain the optimal pelvic alignment. The back support should contact the back of the pelvic area and transfer force to restrain the pelvic area from tilting backward on the seat support. Achieving the desired optimized pelvic alignment is possible only because the back support contacts the pelvic area to hold it in the desired orientation. By itself, the seat support is substantially incapable of preventing the pelvic area of the user from tilting backward. The back support must therefore perform the essential role of maintaining a safe, comfortable, secure and desired pelvic alignment with the seat support.
In addition, the back support should play an additional important role of balancing the upper torso of the user in a comfortable and supportive manner over the pelvic area. The pelvic area is principally responsible for transferring the weight of the upper torso of the user to the seat support, so balancing the weight above the pelvic area is the most effective manner by which to transfer that weight. Without balancing the upper torso of the user above the pelvic area, the user may experience the sensation of the upper torso falling forward or the pelvic area sliding forward off of the seat support. Furthermore, not properly balancing the weight of the upper torso over the pelvic area will create a distortion to the desired alignment and interaction of the pelvic area with the seat support, and over time will diminish or destroy the desired effects of proper pelvic alignment with the seat support, leading to the health and safety concerns described above.
In many circumstances involving previous seating devices, it is impossible to position the back support to maintain proper alignment and orientation of the pelvic area and also orient the back support to balance the weight of the user's upper torso. Adjusting the back support to maintain the optimal orientation of the pelvic area did not permit balancing the weight of the upper torso over the pelvic area, causing the user to experience the sensation of falling forward or sliding forward off of the seat support. Similarly, if the back support was adjusted to balance the weight of the upper torso, the pelvic area was not maintained in the optimal alignment, resulting in an increase in discomfort and fatigue, and in the case of a wheelchair user, possible dangerous pressure ulcers and shear force abrasions, as well as reductions in the desired optimal posture, posture control, support, stability, range of motion, balance, and comfort, among other things. Consequently, it became necessary to compromise one or both of the optimal pelvic alignment or the upper torso orientation.
Attempts have been made in the past to address some of these issues. One particular device employs a back support having a cushion with a contour that projects forward at a location adapted to support the pelvic area while providing a limited range of back support orientation to assist locating the upper torso weight over the pelvic area. Another particular device uses hinges which allows a bottom portion of the back support to pivot relative to an upper portion of the back support, thereby allowing the bottom portion of the back support to interact with the pelvic area while the upper portion of the back support interacts with the upper torso of the user. Both of these prior devices provide greater flexibility in adjusting the position of the upper torso for weight balance over the pelvic area, but both of these prior devices fail to provide the most desirable benefits for interacting with the tissue and skeletal structure of the pelvic area.
In accordance with the general nature of the present invention, new and improved apparatus and methods provide optimal back support orientation for the upper torso of a seating device user without adversely affecting the optimal pelvic alignment of the user with the back support and seat support. The present invention makes it possible to optimize the orientation of the back support to balance the upper torso over the pelvic area without disturbing or compromising the optimal alignment of the pelvic area, without disturbing or compromising optimal upper torso orientation, pelvic alignment and support of posterior superior iliac spines of the pelvic skeletal structure of the user. Further still, the present invention makes it possible to obtain a better degree of comfort, support, confinement and stability around the tissue of the pelvic area, while still obtaining the optimized benefits of alignment and orientation of the pelvic area and upper torso. As a consequence of the present invention, it is no longer necessary to compromise one or both of the optimal pelvic alignment or the upper torso orientation, thereby obtaining optimum improvements in posture, control, support, stability, range of motion, balance, maneuverability and comfort, among other things, for the user of a seating device such as a wheelchair.
One inventive aspect described herein relates to an apparatus and method for supporting a back support from of a frame of a seating device, such as canes of a wheelchair. The back support contacts an upper torso and supports posterior superior iliac spines of a pelvic skeletal structure of a user while seated on a seat support. Under these circumstances, gluteal and buttocks tissue of the user is located above a rear portion of the seat support. In one regard of this inventive aspect, a substantially rigid back shell orients and retains the back support to contact and support the upper torso of the user while simultaneously maintaining support on the posterior superior iliac spines independently of the angular orientation of the back shell and upper torso. A back support orientation mechanism is operatively connected between the back shell and the frame to position and orient the back shell. The back support orientation mechanism pivots the back shell about a pivot point. A lower edge of the back shell is located below an alignment reference extending between the pivot point and posterior superior iliac spines when the user is seated on the seat support and above a substantial majority of the gluteal and buttocks tissue. In another regard of this inventive aspect, the upper torso of the user is supported within the upper portion of the back support, the posterior superior iliac spines are supported with a lower marginal area of the back support to maintain a desired alignment of the pelvic structure with the user seated on the seat support, the back support is pivoted about a pivot point to change the angular orientation of the upper portion of the back support and the upper torso without substantially changing the support on the posterior superior iliac spines by the lower marginal area of the upper portion of the back support, the lower marginal area of the upper portion of the back support is positioned below a reference extending between the pivot point and the posterior superior iliac spines and above a substantial majority of the gluteal and buttocks tissue when the user is seated on the seat support, and the lower portion of the back support is angularly extended at a predetermined angle relative to the upper portion of the back support to contact and support the gluteal buttocks tissue below the posterior superior iliac spines. In these regards, the lower edge of the back shell and lower marginal area of the back support is limited to a location no lower than is necessary to transfer support through the back support cushion to the posterior superior iliac spines. Consequently, optimal orientation and alignment conditions are obtained from both the back support and the seat support.
Another inventive aspect relates to a mechanism and method for orienting a back shell from a frame of a seating device, such as canes of a wheelchair. In regard to this inventive aspect, an attachment bracket is connectable to the frame; an attachment assembly is connectable to the back shell; and an adjustment assembly is operative between the cane bracket and the attachment assembly to permit independently adjustable movement and retention of the attachment assembly relative to the attachment bracket in forward and backward directions, in upward and downward directions and in forward and backward pivotal directions independently of any movement and retention in any of the other directions. The upper torso of the user can be oriented at an optimal and desired angle to balance the weight on the pelvic skeletal structure of the user seated on the seat support, without disturbing the proper and safe supportive relationship of the posterior superior iliac spines with the back support, while eliminating forces which make the upper torso feel as though it is falling forward or the pelvic area is sliding forward on the seat support.
An additional inventive aspect relates to a back support cushion and a method of forming a back support cushion. The back support cushion supports an upper torso and gluteal and buttocks tissue of a user, for example a wheelchair user, when seated on a seat support of a seating device, for example a wheelchair. The seating device has a back shell that is oriented for retaining and orienting the back support cushion to contact an upper torso of the user without substantially disturbing the desired interaction and support of the posterior superior iliac spines by a lower portion of the seat support cushion. An upper portion of the back support cushion is retained by the back shell to contact the upper torso of the user and the posterior superior iliac spines; a lower portion of the seat support cushion extends from the upper portion and below the back shell to contact and support the gluteal and buttocks tissue of the user. At least one brace member extends between the upper and lower portions to retain the lower portion in supportive contact with the gluteal and buttocks tissue of the user. The brace member resists changes in orientation of the lower and upper portions of the back support cushion with respect to one another.
A further inventive aspect involves a method of fitting a back support cushion to an upper torso of a user of a seating device, for example a wheelchair, without adversely affecting support of posterior superior iliac spines of a pelvic skeletal structure of the user when seated on the seat support. The inventive method involves attaching a back shell to the frame, for example canes of a wheelchair, to pivot about a pivot point; adjusting a vertical position of the back shell to position a lower edge of the back shell below an alignment reference extending between the pivot point and posterior superior iliac spines and above a substantial majority of the gluteal and buttocks tissue of the user when seated on the seat support; adjusting a pivoted orientation of the back shell about the pivot point to extend the back shell at an angular orientation for balancing the weight of the upper torso over the pelvic skeletal structure without inducing forces on the posterior superior iliac spines that push the pelvic area forward or induce the upper torso to fall forward; temporarily attaching at least one elongated stay to the back shell, each stay having an upper part adjoining the back shell and a lower part extending below the lower edge of the back shell, the temporary attachment of each stay to the back shell replicating a position of the upper part of each stay within the back support cushion when the back support cushion is retained against the back shell; adjusting an angle of the lower part of each stay relative to the upper part of each stay to align the lower part of each stay to contact and support the gluteal and buttocks tissue below the lower edge of the adjusted height back shell while the upper torso extends at the adjusted pivot orientation of the back shell, the lower part of each stay angled relative to the upper part of each stay supporting and confining the gluteal and buttocks tissue when the user is seated on the seat support; disconnecting each temporarily attached stay from the back shell; assembling each disconnected stay into the back support cushion to occupy substantially the same position relative to the back shell when the assembled back support cushion is retained by the back shell that each stay occupied when temporarily attached to the back shell; and retaining the assembled back support cushion against the back shell.
Additional subsidiary aspects of this inventive method of fitting the back support cushion involve temporarily attaching a flexible contour platform relative to the back shell with the back shell adjusted to the pivot orientation, the temporary attachment of the contour platform replicating a position of the contour platform relative to each stay within the back support cushion when the back support cushion is retained against the back shell; and disconnecting the temporarily attached contour platform from the back shell and assembling the disconnected contour platform into the back support cushion to occupy substantially the same position within the assembled seat support cushion that the contour platform occupied when temporarily attached relative to the back shell. Another subsidiary aspect involves attaching pelvic support wedges to the temporarily attached contour platform at positions adjacent to the back shell to provide support for the iliac crests of the pelvic skeletal structure from the pelvic support wedges when the user is seated on the seat support; disconnecting the temporarily attached contour platform from the back shell after the pelvic support wedges have been attached to the contour platform; and assembling the disconnected contour platform with the attached pelvic support wedges into the back support cushion to occupy substantially the same positions that the contour platform and pelvic support wedges occupied when the contour platform was temporarily attached relative to the back shell.
The inventive aspects are described specifically in the appended claims. A more complete appreciation of the inventive aspects and their scope, as well as the manner in which they obtain improvements and other benefits, can be better appreciated by reference to the following detailed description of presently preferred embodiments and the accompanying drawings, which are briefly summarized below.
A back support orientation mechanism 30 and a back support 32 used with a wheelchair 34 are shown in
The wheelchair 34 is one example of a seating device to which the present invention may be applied. Using the present invention in connection with the wheelchair 34 provides many significant improvements in the field of wheelchairs and support for users of wheelchairs, but the invention may be applied in other different applications and devices in which an individual is seated.
As shown in
In accordance with different aspects of the invention, all of which are described in greater detail below, the pelvic area 42 and pelvic skeletal structure 43 (
The wheelchair 34 is conventional. Two drive wheels 50 are attached to the wheelchair frame 38. The user 44 rotates the drive wheels to maneuver the wheelchair 34. A generally horizontal platform 54 is part of the wheelchair frame 32 to locate and support the seat support cushion 47. A foot rest 56 extends downward at the forward edge of the platform 54 to support the feet of the wheelchair user. Casters 58 extend from the foot rest support in front of the drive wheels 50 to provide the stability of a four-wheeled vehicle, since the center weight point of the wheelchair user 44 is located in front of the center of the drive wheels 50 and behind the casters 58.
One back support orientation mechanism 30 is attached to each of the canes 36. The canes 36 extend upward from opposite lateral sides of the wheelchair frame 38, as shown in
A latch assembly 66 of each back support orientation mechanism 30 is connected to a back shell attachment bracket 68, and the back shell attachment bracket 68 is connected to the back shell 40, as shown in
The forward and backward pivoting movement available from the adjustment assembly 70 of the back support orientation mechanism 30, is shown in
Movement of the back shell 40 horizontally forward and backward is also accomplished by the adjustment assembly 70 of the back support orientation mechanism 30, as shown in
Movement of the back shell vertically upward and downward is also accomplished by the adjustment assembly 70 of the back support orientation mechanism 30 as shown in
The vertical upward and downward movement of the angle adjust bracket 72 relative to the depth adjustment bracket 78 is intended to finely position the height of the back shell 40 relative to the skeletal structure of the wheelchair user. More significant changes in the upward and downward position are achieved by repositioning the location of the cane attachment bracket 60 on the canes 36.
Further refinements in positioning the back shell 40 according to the anatomical requirements of the wheelchair user are achieved by independently adjusting each back support orientation mechanism 30 relative to the other orientation mechanism 30 connected on the opposite side of the back shell 40. Each orientation mechanism 30 can be attached at a different height on its cane 36. Each orientation mechanism 30 can pivot to a degree different from the other orientation mechanism 30. Each of the orientation mechanisms 30 can move forward or rearward to a different position than the other orientation mechanism 30 is moved. Each orientation mechanism 30 can move upward and downward relative to the other orientation mechanism 30. These relatively different pivoting, horizontal and vertical positions are achievable through the attachment of back shell adjustment bracket 68 to the back shell 40, by using upper and lower slots 84 and 86 formed in the back shell 40 (
The ability to achieve a high degree of individualized adjustment in position of the back shell is particularly important in achieving proper and safe seating posture, particularly for wheelchair users who have physical disabilities and associated posture and postural control impairments such as those typically caused by congenital disorders, as well as for other wheelchair users who have a more typical size and shape but have been disabled by acquired or traumatic injuries. In all cases, the back support cushion can be adjusted to safely and securely support and balance the weight of the upper torso 48 above the pelvic area 42 without disturbing or otherwise compromising the optimal pelvic support from the back support 32 and the seat support 46.
The adjustability and variation of the back support 32 made possible by the back support orientation mechanism 30, as shown in
A more complete understanding of the functionality and mechanical details of the back support orientation mechanism 30 is available from the following description taken in conjunction with
The cane attachment bracket 60, the depth adjustment bracket 78, the angle adjust bracket 72 and the latch assembly 66 of the back support orientation mechanism 30 are shown in separated spatial relationship with respect to one another in
The cane attachment bracket 60 secures the back support orientation mechanism 30 to the cane 36 by a clamp body portion 90 which is located at the opposite upper and lower ends of the cane attachment bracket 60 and by the hinge clamp arms 62 which are pivotally connected at hinge pins 92 to each clamp body portion 90. Each hinge clamp arm 62 pivots about the hinge pin 92 with respect to the clamp body portion 90. Each hinge clamp arm 62 is retained around the cane 36 (
Elongated slots 95 are formed in each hinge clamp arm 62 to align with holes 96 formed in the clamp body portions 90 when the clamp arms 62 are in a closed clamping position (
Each cane attachment bracket 60 is attached to one cane 36 by opening the hinge clamp arms 62, positioning the cane attachment bracket 60 with the clamp body portions 90 adjacent to the canes 36, pivoting the hinge clamp arms 62 to a closed position adjacent to the clamp body portions 90, and then tightening the retention bolts 64 to retain the attachment bracket 60 squeezed against the cane 36 between the pivoting hinge clamp arms 62 and the clamp body portions 90. In addition, the cane attachment bracket 60 may be positioned along the cane 36 by loosening the retention bolts 64 and moving the cane attachment bracket 60 along the cane 36 through the multi-sided conduit 94 until a desired position is reached, and then tightening the retention bolts 64. The procedure of adjusting the position of the cane attachment brackets 60 along the length of the canes 36, after loosening the retention bolt 64, establishes an initial vertical position of the back shell 40 relative to the pelvis and upper torso 48 of the user 44.
An adjustable set screw 101 is used to finely position the lateral orientation of the multi-sided conduit 94 through the upper clamp body portion 90 and hinged clamp arm 62 in the situation where the cane attachment bracket 60 spans over a changed diameter portion 39a and 39b of a telescopic cane 37, as shown in
In the situation where the desired location for the cane attachment bracket 60 spans the changed diameter point of the cane portions 39a and 39b, the cane attachment bracket 60 is maintained in a lateral orientation surrounding both different-diameter cane portions 39a and 39b by adjusting the set screw 101 to contact the upper cane portion 39a and prevent it from contacting the side of the multi-sided conduit 94 opposite from the hinged clamp arm 62. The set screw 101 then maintains the vertical orientation of the multi-sided conduit 94 parallel to both telescopic cane portions 39a and 39b, thereby preventing loss of the vertical orientation of the cane attachment bracket 60 which could cause binding of the back support orientation mechanism 30.
The depth adjustment brackets 78 allow for the horizontal adjustment of the back shell 40 relative to the canes 36 or 37 between the forward-most position of the back shell (
The front and back position of the back shell 40 and back support 32 is changed by loosening the retention bolts 80, horizontally moving the back shell 40 forward or backward relative to the canes 36 or 37 (which causes the depth adjustment bracket 78 to move forward or backward relative to the cane attachment bracket 60), and then tightening the retention bolts 80 when the back shell 40 is in the desired position.
The connection of the angle adjust bracket 72 to the depth adjustment bracket 78 allows vertical adjustment of the back shell 40 relative to the canes 36 or 37 between the highest fine adjustment position (
The vertical position of the back shell 40 is changed by loosening the retention bolts 82, vertically moving the back shell 40 up or down relative to the cane attachment bracket 60 to the extent permitted by the vertical length of the slots 108, and then tightening the retention bolts 82 when the back shell 40 is in a desired position. Of course, the vertical height of the back shell 40 can also be adjusted by loosening the retention bolts 64 which control the retention from the pinch clamp arms 62 to the clamp body portion 90 as previously discussed. The vertical adjustment provided by moving the angle adjust bracket 72 relative to the depth adjustment bracket 78 along the length of the vertical slots 108 is used principally to finely adjust the height of the back shell 40, while movement of the cane adjustment brackets 60 relative to the canes 36 or 37 is for more coarse adjustment of the height of the back shell 40. This fine vertical adjustment capability of the adjustment assembly 70 is significant in the circumstance where accessories mounted to the canes 36 restrict the mounting positions of the cane attachment brackets 60.
The angle adjust brackets 72 also allow for the forward and backward pivoting orientation of the back shell 40 between a maximum rearwardly reclined orientation (
The latch assembly 66 is connected to the angle adjust bracket 72 by the pivot bolt 74 and the angle retention bolt 76. The pivot bolt 74 is passed through the pivot hole 114 from an outward facing surface of the angle adjust bracket 72, through a spacer washer 122, and then threaded into the lower threaded hole 118. The angle retention bolt 76 is passed through the arcuate slot 116, passed through a spacer washer 124, and then threaded into the upper threaded bolt hole 120. The spacer washers 122 and 124 separate the angle adjust bracket 72 and the latch assembly 66 to prevent interference between the flange portions of the flange nuts 112 and the latch assembly 66 when the latch assembly 66 pivots relative to the angle adjust bracket 72, as well as to create enough space for movement of an actuation lever 152 of the latch assembly 66 when operating the latch assembly 66.
The pivoted angle of the back shell 40 is adjusted by loosening the angle retention bolt 76 and the pivot bolt 74, pivoting the back shell 40 to a desired pivoted orientation relative to the canes 36 or 37, and then tightening the angle retention bolt 76 and pivot bolt 74. The pivot bolt 74 is formed and threaded into the lower hole 118 in a manner which secures a rigid pivot point for the latch assembly 66 relative to the angle adjust bracket 72 but which does not interfere with the pivoting movement of the latch assembly 66 relative to the angle adjust bracket 72.
The details of the latch assembly 66 are described below with reference to
Extending between the two side plates 132 and 134 and positioned above and below the openings 138 and 136 are a receiver post 142 and a latch post 144. The posts 142 and 144 each extend through openings formed in the inward and outward facing side plates 132 and 134. A latch receiver 146 is pivotally mounted to the receiver post 142. The latch receiver 146 has a U-shaped portion 148 defined by legs 143 and 145. The latch receiver 146 rotates between a forward open and unlocked position shown in
Forward rotational movement of the latch receiver 146 is limited by a forward stop pin 147 which extends between the inner and outer facing side plates 132 and 134. Rearward rotational movement of the latch receiver 146 is limited by an adjustable set screw 149 threaded through a hole in a rear portion of the C-shaped receiver body 150. By adjusting the position of the set screw 149 relative to the latch receiver 146, a predetermined range of pivoting movement of an upper latch pin 180 (
A latch release cam 150 is attached to the latch post 144 and rotates between a locked position shown in
A dual coil bias spring 156 is formed by an upper coil 158 which winds around the receiver post 142 and a lower coil 160 which winds around the latch post 144. Right-angled ends of the bias spring 156 are inserted into holes formed into the latch receiver 146 and in the latch release cam 150. Winding the coils 158 and 160 around the posts 142 and 144 develops bias force which is transferred to the latch receiver 146 and the latch release cam 150. The latch receiver 146 is biased into the forward-pivoted open position (
A deformable elastomer piece 166 is located within a bottom portion of the C-shaped receiver body 130 in a position to be exposed in the lower opening 138. The elastomer piece 166 has a concave arcuate recess, similar to the convergence of the lower opening 138, when viewed from the inward and outward sides of the latch assembly 66. The elastomer piece 166 is positioned slightly above the converging edges 140 of the lower opening 138. The purpose of the elastomer piece 166 is to induce a slight resilient force on a lower latch pin 182 (
Each back shell attachment bracket 68, which connects the back shell 40 to both latch assemblies 66, has upper and lower base mounts 168 which mate against flat mounting areas 170 on a back surface of the back shell 40, as shown in
The distance between the back shell attachment brackets 68 is adjustable to accommodate different widths between the cane 36 of different types of wheelchair frames 38. Typically, the back shell attachment brackets 68 are spaced equidistant from the lateral center of the back shell 40, but may also be positioned off-center depending on the needs of the user 44. The back shell attachment brackets 68 are also typically attached to the back shell 40 with both lateral top and bottom edges (186 and 187,
Extending outwardly from each back shell attachment bracket 68 is a pair of vertically spaced apart, upper and lower latch pins 180 and 182. The latch pins 180 and 182 connect the back shell attachment brackets 68 to the latch assemblies 66. The latch pins 180 and 182 are received within the upper and lower openings 136 and 138, while the latch assemblies 66 are in the open unlocked position (
The back shell attachment brackets 68 and the back shell 40 are connected to the latch assemblies 66 by tilting the back shell attachment brackets 68 and back shell 40 forward to insert the lower latch pins 182 into the lower openings 138. The insertion of the lower latch pins 182 into the lower openings 138 continues until the lower latch pins 182 contact the elastomer pieces 166 at the bottom of the lower converging opening 138, as shown in
With the latch release cam 150 rotated backward, the teeth 162 within the V-shaped recesses 164 retain the latch receivers 146 in the closed locked positions (
The physical spacing between the upper opening 136 and the arcuate recess of the elastomer piece 166 is slightly less than the spacing between the upper and lower latch pins 180 and 182. The reduced spacing causes the lower latch pin 182 to deform the elastomer piece 166 slightly when the upper latch pin 180 retained by the latch assembly 66. The back shell attachment brackets 68 are thus restrained from vertical movement relative to the latch assemblies 66 to prevent mechanical rattling of the latch pins 180 and 182 within the openings 136 and 138.
A lower edge 186 of the back shell 40 has a vertical shape that delivers support through the back support 32 to the posterior superior iliac spines 57 and the iliac crests 61 (
One of the advantages of the back support mechanism 30 as previously described is that the back support 32 will not fall posteriorly, if for some reason the latch assemblies 66 should be accidentally released and moved to the open unlocked position. The back support 32 will remain in front of the canes 36 or 37, thereby reducing the risk of potential injury to the wheelchair user from falling backwardly through the canes. The nature of the connection of the back support orienting mechanisms 30 on the canes 36 or 37 causes the canes themselves to diminish the risk of injury to the wheelchair user from falling rearwardly against the canes.
A more complete understanding of the functionality and the mechanical and assembly details of the back support cushion 47 are shown and described in conjunction with
The envelope cover 190 encloses a padding layer 200 which generally takes the shape of the outer periphery of the back support 32. The padding layer 200 is preferably a conventional open cell foam material which provides resilient padding for the user against which to rest his or her upper torso 48. The padding layer 200 is located in front of a flexible contour adjustment platform 202. The contour platform 202 is preferably a uniform thickness piece of thermo-moldable closed cell foam which generally has the shape of the outer periphery of the back support 32. A V-shaped notch 204 is formed in the foam layer 200 at a location centered along the bottom edge 186 of the back support cushion. The purpose of the V-shaped notch 204 is to provide a relief area to prevent undue pressure on the sacrum 59 of the pelvic skeletal structure 43 of the user (
Elongated and rectangularly shaped brace members or stays 206 are also confined within the envelope cover 190. The stays 206 are located behind the contour platform 202. The stays are adjustable and are intended to transfer support and confinement through the contour platform 202 and the foam layer 200 to the gluteal or buttocks tissue of the wheelchair user. As described below, the lower edge 186 of the back shell 40 terminates above the majority of the gluteal or buttocks tissue 236 (
The stays 206 are confined to the rear cover piece 194 of the envelope cover 90 by insertion into pockets 208. Each pocket 208 is formed by sewing or attaching a strip of material to the inside surface of the rear cover piece 194. The width of each pocket 208 is slightly greater than the width of the stay 206, causing the stay 206 to remain firmly in position without substantial side-to-side lateral or pivoting movement when each stay 206 is inserted in each pocket 208.
As shown in
The hook and loop strip 210 on the rear cover piece 194 mates with a complementary strip 212 of hook and loop material which has been attached to the back shell 40, preferably with an adhesive. Mating the hook and loop strips 210 and 212 holds the back support cushion 47 in place on the back shell 40.
The back support cushion 47 is also held in place on the back shell 40 by a flap 214 of the same type of material as the rear cover piece 194 which extends from an upper edge of the lower cover piece 194. The flap 214 has a strip 216 of conventional hook and loop material attached to it, and a complementary strip 218 of conventional hook and loop material is attached to the outer surface of the rear cover piece 194 adjacent to the location from which the flap 214 extends. As shown in
Sufficient retention force for holding the back support cushion 47 on the back shell 40 is available from mating the hook and loop strips 210 and 212 on the rear cover piece 194 and on the back shell 40, and from wrapping the flap 214 around the handle 189 and connecting the hook and loop strips 216 and 218. Retained in this manner, the back support cushion 47 is retained in a consistent, effective position on the back shell as part of the back support 32.
Elongated vertical strips 220 of conventional hook and loop material are attached on laterally opposite sides of the front surface of the contour platform 202. The strips 220 are positioned to mate with conventional hook and loop material (not shown) attached on the back side of pelvic support wedges 222. The pelvic support wedges 222 taper in both the transverse and height dimensions from a broader and thicker end 224 to a narrower and thinner end 226. As discussed below, the pelvic support wedges 222 are included within the back support 32 to provide support for the posterior-lateral surfaces of the superior aspect of the pelvic skeletal structure 43 at iliac crests 61 of the illums 55 (
Two additional strips 228 of conventional hook and loop material are attached to the rear surface of the contour platform 204. These additional strips 228 are used to hold the contour platform 202 in position when fitting the components of the back support cushion 47 to the user, as described below. These additional fitting strips 228 are located in a position which generally coincides with the location of the pockets 208 and the stays 206 within the pockets 208.
The back support 32 is assembled, after it has been fitted in the manner described below in connection with
A more complete understanding of the fitting and use of the back support 32 is obtained by reference to the following description and
As shown in
The back shell 40 has previously been attached to the canes 36 or 37 of the wheelchair frame 38 using the back support orientation mechanisms 30. The cane attachment bracket 60 is loosely connected to the canes 36 or 37 to allow vertical movement of the back shell 40 relative to the pelvic area 42 and upper torso 48 of the user. The stays 206 are attached to the hook and loop strips 212 on the back shell 40. The hook and loop strips 212 are located on the back shell 40 at the position in which the stays 206 will be retained in the pockets 208, when the back support cushion 47 is attached and retained to the back shell 40. By placing the stays 206 on the hook and loop strips 212 as shown in
To facilitate placement of the stays 206 on the hook and loop strips 212, small pieces 234 of hook and loop material are attached to the front and back sides of the stays 206. The hook and loop pieces 234 are used only for the purpose of fitting. When the stays are inserted in the pockets 208, the hook and loop pieces 234 are inserted entirely within the pockets 208. After the stays 206 have been temporarily attached to the forward facing surface back shell 40 as shown in
The contour platform 202 is attached to the stays 206 in the same position that the contour platform will occupy in the assembled back support 32. This position is established relative to the stays 206 and the upper edge 187 (
Although the contour platform 202 is shown with a preformed V-shaped notch 204, the contour platform 202 could be supplied without the V-shaped notch 204 to allow an appropriately shaped notch to be cut into the contour platform 202 having size, shape and location to avoid the sacrum 59 of the individual wheelchair user. After the stays 206 and the contour platform 202 have been temporarily attached to the back shell 40, the user is positioned on the seat support 46.
With the user seated on the seat support 46, the back support orientation mechanisms 30 are moved along the upright extending canes 36 or 37 until the pivot point at the pivot bolt 74 is generally horizontally aligned and referenced with the posterior superior iliac spines 57 of the pelvic skeletal structure 43 in the pelvic area 42 (
It is important that the lower edge 186 of the back shell 40 does not extend farther below the alignment reference between the pivot bolt 74 and the posterior superior iliac spines 57 than is necessary to provide the adequate support to the posterior superior iliac spines 57 to maintain the pelvic structural area in the desired alignment. In general, for most individuals, that desired pelvic structural alignment is a horizontal reference between the posterior superior iliac spines 57 and anterior superior iliac spines 63 (
Maintaining the lower edge 186 of the back shell 40 no lower than this position of adequate support will have the effect of not distorting the desired alignment of the pelvic skeletal structure 43 relative to the back support 32 and the seat support 46 when the back support 32 is oriented at a desired angle to balance the weight of the users upper torso over the pelvic area 42. As the angular orientation of the seat support 32 is changed, the relative position of the back support 32 to the posterior superior iliac spines 57 is maintained without significant change. Maintaining the support on the posterior superior iliac spines 57 with the back support 32 while changing the orientation of the back support 32 through a wider range of orientations is an essential part of avoiding many of the comfort and safety problems that users might otherwise face.
Once the desired vertical height of the back shell 40 is achieved, with the lower edge 186 positioned in the described manner below the alignment reference between the pivot bolt 74 and the posterior superior iliac spines 57, the retention bolts 64 are tightened to constrict the hinged clamp arms 62 around the clamp body portions 90 of the cane attachment bracket 60 in each back support orientation mechanism 30 (
Next, as understood from
With the contour platform 202 remaining in the same position that it will occupy in the assembled back support 32, as shown in
The next adjustment is the pivot orientation angle of the back shell 40. The optimal pivot orientation of the back support 32 varies for different users. The proper pivot angle establishes a sense of balance which does not make the user feel as though he or she may fall forward or slide out of the wheelchair. A important aspect of the present invention is that the previously adjusted proper posture of the pelvic skeletal structure 43 is not altered when the angle of the back shell 40 is adjusted.
In establishing the proper degree of pivot orientation, the bottom edge 186 of the back shell 40 pivots only very slightly upward or downward while maintaining contact with the posterior superior iliac spines 57 to provide support for the pelvic skeletal structure 43. The slight degree of upward or downward movement of the bottom edge 186 of the back shell 40 results because of the pivot point of the back shell at the pivot bolt 74 is displaced posterior from the point at which the back support 32 contacts the posterior superior iliac spines 57. Most importantly, however, the areas (230,
If a different pivot angle is desired on one side of the wheelchair compared to the pivot angle on the other side of the wheelchair, the rigid back shell 40 offers enough torsional flexibility to accommodate such angular differences by moving the positions of the retention bolts 178 in the slots 84 and 86. Differences in forward and backward position of the shell from one side of the wheelchair to the other side of the wheelchair are also accommodated by the movement of the position of the retention bolts 178 in the slots 84 and 86. Differences in height of the back shell 40 from one side of the wheelchair to the other side of the wheelchair are also accommodated by movement of the retention bolts 178 in the slots 84 and 86.
Of course, the ability to make individual adjustments in the orientation of the back shell on opposite sides of the wheelchair results from the multiple independent adjustments available from each back support orientation mechanism 30. These individual adjustments on opposite lateral sides of the wheelchair will accommodate almost any upper torso shape of a wheelchair user and still assure optimal orientation of the upper torso 48 on the back support 32 and optimal alignment of pelvic skeletal structure 43 (
Either after the angular orientation of the back shell 40 has been established, or in conjunction with establishing the angular orientation of the back shell 40, lower portions of the stays 206 below the lower edge 186 of the back shell 40 are bent, at the location of the lower edge 186, as shown in
As understood from
The angular orientation of the inverted V-shape of the lower edge 186 (
Although
During this fitting process, the stays 206 have been bent to the desired configuration to provide individualized gluteal and buttocks tissue support and confinement. The position and size of the notch 204 in the contour platform 202 has been adjusted or evaluated to avoid excessive pressure from the back support 32 on the sacrum 59. The position of the pelvic support wedges 222 have been established to provide the best support for the pelvic skeletal structure 43 at the level of the posterior iliac crests 61. With these individualized features having been established, the back support 32 can now be assembled.
The contour platform 202 with the optionally attached wedges 222 and the bent stays 206 are removed from the back shell 40. The contour platform 202 with the attached pelvic support wedges 222 is inserted through the open zipper 196 in the envelope cover 190 and positioned behind the padding layer 200. The bent stays 206 are inserted in the pockets 208 in the rear cover piece 194 through the open zipper 196 of the envelope cover 190. The zipper 196 is closed, and the assembled back support 32 is attached to the back shell 40 by wrapping the flap 214 around the handle 189 while contacting the hook and loop strip 210 on the back surface of the rear cover piece 194 to the connecting hook and loop strip 212 on the back shell 40.
In addition to the benefits of individualized support from assembling fitted components into the back support 32 and the adjustments available from the back support orientation mechanism 30, the manner by which desired angular orientation of the back support 32 is achieved does not interfere with the optimal alignment of the pelvic skeletal structure 43 is understood from
As shown in
In contrast to the benefits and improvements shown in
The forward push from the lower portion of the prior art back shell 250 and the back support cushion 254 distorts the relationship of the pelvic skeletal structure 43 with a seat support 256 by pushing the pelvic skeletal structure 43 in a forward or other misaligning direction, creating potentially harmful pressure at the sacrum 59 and coccyx 65 (
Furthermore, there is no capability to adjust the interaction of the rearwardly and downwardly tapered lower portion of the back support cushion 254 with the gluteal and buttocks tissue 236 in the prior art arrangement shown in
The significance of the benefits and improvements described herein will become more apparent upon gaining a full appreciation of the present invention. Preferred embodiments of the invention and many of its improvements have been described previously with a degree of particularity. This detailed description is of a presently preferred example of implementing the invention. The scope of the invention is defined by the following claims.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4615856 | Silverman | Oct 1986 | A |
| 4883320 | Izumida et al. | Nov 1989 | A |
| 5211446 | Jay et al. | May 1993 | A |
| 5364162 | Bar et al. | Nov 1994 | A |
| 5556168 | Dinsmoor, III et al. | Sep 1996 | A |
| 5593211 | Jay et al. | Jan 1997 | A |
| 6059370 | Kanyer et al. | May 2000 | A |
| 6095611 | Bar et al. | Aug 2000 | A |
| 6186594 | Valiquette et al. | Feb 2001 | B1 |
| 6257664 | Chew et al. | Jul 2001 | B1 |
| 6460933 | Bors et al. | Oct 2002 | B1 |
| 6659563 | Float et al. | Dec 2003 | B2 |
| 6688693 | Christofferson et al. | Feb 2004 | B2 |
| 7104610 | Cramer | Sep 2006 | B2 |
| 7216388 | Bieganek et al. | May 2007 | B2 |
| 7854481 | Fraser | Dec 2010 | B2 |
| 7857394 | Whelan et al. | Dec 2010 | B2 |
| 7891739 | Cramer | Feb 2011 | B2 |
| 7980580 | Loewenthal et al. | Jul 2011 | B2 |
| 8070232 | Hung | Dec 2011 | B2 |
| 8186756 | Jorgensen | May 2012 | B2 |
| 8197009 | Whelan et al. | Jun 2012 | B2 |
| 20030052525 | Bors et al. | Mar 2003 | A1 |
| 20030102706 | Float et al. | Jun 2003 | A1 |
| 20050275272 | Fraser | Dec 2005 | A1 |
| 20080157581 | Whelan et al. | Jul 2008 | A1 |
| 20100276974 | Huttenhuis | Nov 2010 | A1 |
| 20120091300 | Bee et al. | Apr 2012 | A1 |
| Number | Date | Country |
|---|---|---|
| WO 9917636 | Apr 1999 | WO |
| WO 2009084961 | Jul 2009 | WO |
| Entry |
|---|
| In the present application, Figures 19-21 and discussion thereof. |
| PCT International Search Report with attached Written Opinion of the International Searching Authority for International Application No. PCT/US2012/027018, dated Jun. 4, 2012, 8 pages. |
| Number | Date | Country | |
|---|---|---|---|
| 20120223560 A1 | Sep 2012 | US |
