Seat cushion with adjustable contour and method of adjusting the contour of a seat cushion

• US 7,373,678 B2
• Filed: 05/27/2005
• Issued: 05/20/2008
• Est. Priority Date: 07/28/2003
• Status: Active Grant

• Current Assignee: Sunrise Medical Us LLC (Sunrise Medical Incorporated)
• Original Assignee: Aspen Seating LLC
• Inventors: Bieganek, Joseph S., Hetzel, Thomas R., Maurus, Steve
• Primary Examiner(s): SAFAVI, MICHAEL
• Application Number:
  US11/140,003
• Publication Number:
  US 20050235423A1
• Time in Patent Office: 1,089 Days
• Field of Search: 565/3, 565/4, 565/41, 565/54, 565/59, 565/2, 565/6, 573/9, 297/452.23, 297/452.26, 297/452.27, 297/452.28, 29/91, 29/911
• US Class Current: 5/653
• CPC Class Codes: A47C 7/021 Detachable or loose seat cushions
• CPC Class Codes: A47C 7/029 of non-adjustable shape adapted to a user contour or ergonomic seating positions
• CPC Class Codes: A61G 5/1043 Cushions specially adapted for wheelchairs
• CPC Class Codes: A61G 5/1045 for the seat portion
• CPC Class Codes: A61G 7/05723 with cut-outs or depressions in order to relieve the pressure on a part of the body mattresses with cavities A47C27/142
• CPC Class Codes: Y10T 29/481 Method

Abstract

A flexible support structure of a seat cushion, such as a wheelchair cushion, has an upper surface with a support contour having relief areas for establishing relatively less pressure on skin adjacent to bony prominences of a user'"'"'s pelvis and having a support area for establishing relatively more pressure on skin covering a tissue mass spaced from the bony prominences. A slit is formed in the rear corner of the support structure and an insertion member is inserted into the slit to change a position of the support area to thereby adjust the support contour for better support of the pelvic area. A cover encases the support structure to resist outward deformation of the support structure. The cover has an extension portion that expands the cover at the rear corner to increase a dimension of the cover to encase an increase dimension of the corner caused by the insertion of the insertion member.

Claims

1. A contoured seat cushion for supporting a person in a seated position thereon, the person having a pelvic area with bony prominences and tissue masses spaced from the bony prominences, the tissue masses including posterior lateral buttocks, comprising:

a support structure made from a resilient material, the support structure including generally opposite front and rear sides, generally opposite left and right sides, a bottom surface extending between the front and rear sides and between the left and right sides, and a top surface generally opposite of the bottom surface and extending between the front and rear sides and the left and right sides;

the top surface configured as a support contour defining relief areas and support areas, the relief areas positioned to align with the bony prominences of a person when the person is seated on the cushion, and the support areas positioned to align with the tissue masses of the posterior lateral buttocks;

an insertion member;

openings formed in each of the rear corners between the top surface and the bottom surface of the support structure to receive the insertion member, the openings positioned between the top surface and the bottom surface, and a support area of the support contour changing position relative to other support areas or relief areas when the insertion member is inserted into one of the openings;

a cover made from a substantially non-stretchable material, the cover sized to encase the support structure to resist substantial outward deformation of the support structure when the person is seated on the seat cushion; and

an expansion portion of the cover positioned adjacent to the rear corner to expand the cover at the corner to fit around the support structure when the insertion member is inserted in the opening, the expansion portion including a zipper and a gusset, the zipper opening to allow the gusset to expand, and the zipper closing to contract the gusset.

2. A method of manufacturing a contoured seat cushion as defined in claim 1, comprising:

forming the support structure to include the generally opposite front and rear sides, the generally opposite left and right sides, the bottom surface and the top surface;

configuring the top surface as the support contour with the relief areas and the support areas;

forming the opening in each of the rear corner of the support structure, each opening adapted to receive the insertion member to articulate the support areas aligned with the tissue masses at the posterior lateral buttocks foward and laterally inward;

encasing the support structure within the cover with the expansion portion positioned adjacent to the rear corner;

inserting the insertion member into the opening; and

expanding the cover at the expansion portion to accommodate an increased dimension of the support structure caused by the insertion of the insertion member into the opening.

3. A method as defined in claim 1, further comprising:

shaping the insertion member substantially as a wedge.

4. A method as defined in claim 1, further comprising:

forming the bottom surface as a convex shape that curves between the left side and the right side.

5. A method of adjusting a contoured seat cushion as defined in claim 1 to support a person in a seated position on the support structure, comprising:

inserting the insertion member into the opening in the corner of the support structure;

adjusting a position of the support area of the support contour by inserting the insertion member into the opening;

restraining the support structure and the support area against outward deformation away from the pelvic area by surrounding the support structure with the cover; and

expanding a portion of the cover to fit over the support structure after the insertion member has been inserted.

6. A contoured seat cushion for supporting a person in a seated position thereon, the person having a pelvic area with bony prominences and tissue masses spaced from the bony prominences;

the bony prominences of the pelvic area include the ischial tuberosities, the greater trochanters and the coccyx and sacrum;

the tissue masses of the pelvic area include the tissue masses on opposite lateral sides of the posterior buttocks and beneath the proximal thigh bones;

the cushion comprising;

a support structure made from a resilient material, the support structure including generally opposite front and rear sides, generally opposite left and right sides, a bottom surface extending between the front and rear sides and between the left and right sides, and a top surface generally opposite of the bottom surface and extending between the front and rear sides and the left and right sides; and

wherein;

the top surface is configured as a support contour defining relief areas and support areas;

the support areas and relief areas are separate from one another;

the relief areas are positioned to align with the bony prominences of a person when the person is seated on the cushion, support areas are positioned to align with the tissue masses of the posterior lateral buttocks;

the support areas are at locations adapted to be adjacent to skin at the tissue masses on the opposite lateral sides of the posterior buttocks and beneath the proximal thigh bones;

the relief areas are at locations adapted to be adjacent to skin covering the ischial tuberosities, the greater trochanters and the coccyx and sacrum; and

the support areas and the relief areas are spaced relatively more toward and relatively more away from the anatomical shape of the pelvic area of the person when the person is seated on and supported by the support contour; and

wherein the cushion further comprises;

an insertion member; and

openings to receive the insertion member, the openings formed in each of the rear corners between the surface and the bottom surface of the support structure, the opening positioned between the top surface and the bottom surface, and wherein;

at least one support area of the support contour changing position relative to other support areas and relief areas when the insertion member is inserted into one of the openings.

7. A contoured seat cushion as defined in claim 6, wherein:

the cushion extends longitudinally from a rear wall at the rear side to the front side and extends transversely between opposite transverse sides, each transverse side extends longitudinally between the rear wall and the front side, and the rear wall has a general midline contour which represents the anatomical shape of a rear portion of the pelvic area of the person;

the support contour is defined relative to a longitudinal midline which extends midway between the opposite transverse sides, and is further defined relative to the horizontal and the vertical, the horizontal having a component which extends longitudinally and transversely and the vertical having a component which extends perpendicular to the horizontal;

the support contour includes a cavity forward of the rear wall and extending downward to a lower surface which is adapted to be located beneath the isohial tuberosities when the person is seated on and supported by the support contour;

the lower surface of the cavity constituting an ischial tuberosities relief area which is spaced from the isohial tuberosities to substantially offload pressure and shear force from the skin adjacent to the ischial tuberosities when the person is seated on and supported by the support contour;

the support contour includes two transverse relief areas spaced transversely to the outside of the cavity and which are adapted to be located beneath the greater trochanters when the person is seated on and supported by the support contour, each transverse relief area is spaced vertically above the lower surface of the cavity;

the transverse relief areas each constituting a greater trochanter relief area which is spaced from each greater trochanter to substantially offload pressure and shear force from the skin adjacent to the each greater trochanter when the person is seated on and supported by the support contour;

the support contour includes a channel in the rear wall at a location approximately centered transversely about the longitudinal midline and recessed rearward into the rear wall relative to the midline contour of the rear wall, the channel is adapted to be located behind and transversely to the sides of the coccyx and the sacrum when the person is seated on and supported by the support contour;

the channel constituting a coccyx and sacrum relief area which is spaced sufficiently from the coccyx and sacrum to substantially offload pressure and shear force from the skin adjacent to the coccyx and sacrum when the person is seated on and supported by the support contour;

the support contour including two rear support areas located on the rear wall on respectively opposite transverse sides of the longitudinal midline and between the channel and the greater trochantors relief areas, each rear support area protruding forward relative to the midline contour of the rear wall, each rear support area is adapted to be located adjacent to the skin and tissue masses on opposite lateral sides of the posterior buttocks when the person is seated on and supported by the support contour;

the rear support areas each constituting lateral posterior buttocks support areas which induce upward support pressure on the opposite lateral sides of the posterior buttocks when the person is seated on and supported by the support contour;

two forward support areas located forward of the cavity and spaced transversely on opposite sides of the longitudinal midline, each forward support area located vertically higher than the greater trochanters relief areas, the forward support areas are adapted to be located beneath the proximal thigh bones at a position which is closer to the greater trochanters compared to the location of knee joints on the thigh bones when the person is seated on and supported by the support contour;

the forward support areas constituting proximal thigh support areas which induce upward support pressure while interacting in a fulcrum-like manner with the proximal thigh bones to create elevational force at the hip joints from weight of the distal legs to elevate the greater trochanters relative to the greater trochanter relief areas when the person is seated on and supported by the support contour; and

the upward support pressure induced from the lateral posterior buttocks support areas and from the proximal thigh support areas transferring substantially the entire support pressure to tissue masses on opposite lateral sides of the posterior buttocks and beneath the proximal thigh bones while substantially offloading support pressure from skin covering the ischial tuberosities and the greater trochanters and the coccyx and sacrum when the person is seated on and supported by the support contour.

8. A contoured seat cushion as defined in claim 7, wherein:

the locations of the proximal thigh support areas establish a lever-like mechanical advantage for increasing the amount of elevational force at the hip joints from the weight of the distal legs.

9. A contoured seat cushion as defined in claim 7, wherein:

the channel has a V-shaped curvature of increasing transverse width with increasing vertical height above the lower surface of the cavity.

10. A contoured seat cushion as defined in claim 7, wherein:

the support pressure from the lateral posterior buttocks support areas prevents the pelvic area from tipping backward in response to the elevational force at the hip joints.

11. A contoured seat cushion as defined in claim 7, wherein:

the upward support pressure induced from the rear support areas and from the proximal thigh support areas also facilitate postural alignment and stabilization of the pelvic area against forward and backward and lateral side to side movement when the person is seated on and supported by the support contour.

12. A contoured seat cushion as defined in claim 7, wherein:

the isohial tuberosities relief area and the greater trochanters relief areas and the coccyx and sacrum relief area are of sufficient size to offload pressure from the skin covering the ischial tuberosities and the greater trochanters and the coccyx and sacrum during normal forward and backward pivoting movement of the pelvic area and an upper torso of the person when seated on and supported by the support contour.

13. A contoured seat cushion as defined in claim 7, wherein:

the support contour includes a clearance area extending upward and forward from the lower surface of the cavity and approximately centered about the longitudinal midline, the clearance area adapted to be located adjacent to a perineal area of the person when seated on and supported by the support contour, the clearance area establishing space for air circulation at the perineal area.

14. A contoured seat cushion as defined in claim 13, wherein:

the integral piece of support material comprises a matrix of resilient adhered-together plastic beads having spaces between the beads to establish permeability for air movement within the integral piece of support material.

15. A contoured seat cushion as defined in claim 14 for use on a wheelchair.

16. A method of adjusting a contoured seat cushion as defined in claim 6 to support a person in a seated position on the support structure, comprising:

inserting the insertion member into the opening in the corner of the support structure; and

adjusting a position of the support area of the support contour by inserting the insertion member into the opening.