SEATING UNIT WITH AUXETIC USER SUPPORT
A seating unit includes a generally horizontal seat portion and a generally upright back portion. The back portion includes a flexible membrane or mesh extending in first and second directions. The mesh defines a generally upright user support surface. At least a portion of the mesh comprises an auxetic material having a negative Poisson's ratio whereby stretching of the auxetic portion of the mesh in at least one of the first and second directions causes the mesh to expand in the other of the first and second directions.
This application claims the benefit of U.S. Provisional Application No. 61/989,396 filed on May 6, 2014, entitled, “SEATING UNIT WITH AUXETIC USER SUPPORT,” the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTIONVarious types of chairs, seating units, and other articles having user support surfaces have been developed. User supports may include foam or other resilient material that is provided in an effort to improve the comfort of a user. However, known user supports may suffer from various drawbacks.
SUMMARY OF THE INVENTIONOne aspect of the present invention is a seating unit including a lower portion that is configured to support the seating unit. The seating unit may comprise a chair, and the lower portion may be configured to support the chair on a floor surface. The seating unit also may include a seating structure supported by the lower portion. The seating structure includes a generally horizontal seat portion and a generally upright back portion. The back portion may include upright frame portions defining a space therebetween and a flexible mesh extending in first and second directions across the space. The flexible mesh may be connected to the upright frame portions to define a generally upright user support surface. At least a portion of the flexible mesh comprises an auxetic material having a negative Poisson's ratio whereby stretching of the auxetic portion of the flexible mesh in at least one of the first and second directions tends to cause the flexible mesh to expand in the other of the first and second directions. The flexible mesh may comprise a molded polymer material such as polypropylene.
Another aspect of the present invention is a user support structure for seating units such as chairs. The user support structure includes a flexible membrane defining front and rear faces and opposite edge portions. The flexible membrane includes a high pressure region that is configured to support portions of a user's body when a user's body comes into contact with the high pressure region of the flexible membrane. The flexible membrane defines a lower pressure region adjacent the high pressure region. The high pressure region and the lower pressure region comprise auxetic material whereby stretching of the flexible membrane in a first direction tends to cause the material to expand in a second direction that is transverse to the first direction. The flexible membrane is significantly more compliant in the high pressure region than the lower pressure region in response to a force that is applied to the front face of the flexible membrane. The user support structure further includes a pair of spaced apart frame portions extending along the opposite edge portions of the flexible membrane. The opposite edge portions of the membrane are connected to the frame portions. The opposite edge portions of the membrane may be integrally formed with the frame portions.
Another aspect of the present invention is a user support for seating units or other articles having a surface configured to support a user. The user support comprises a polymer mesh material including a plurality of links forming interconnected auxetic cells. Each auxetic cell has a length defined along a first cell axis and a width defined along a second cell axis that is transverse to the first cell axis. The auxetic cells comprise a plurality of interconnected flexible links configured such that stretching of the auxetic cells along the length of the auxetic cells causes the width of the auxetic cells to increase. A plurality of the auxetic cells are arranged about a center in a generally circular pattern to provide a region having increased compliance. The auxetic cells may be arranged such that the first cell axes are arranged in a radial pattern about the center, or in a circumferential pattern about the center.
These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.
For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in
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The seat portion 4 includes an upwardly-facing support surface 12 that may comprise fabric or other material that extends over a foam core (not shown). Chair 1 may optionally include armrests 14A and 14B. The armrests 14A and 14B may have virtually any configuration as required for a particular application.
The back portion 6 of chair 1 includes a support structure 16 having lower portions 18A and 18B that movably interconnect the back portion 6 to the base 2. The support structure 16 may also include upwardly-extending supports 20A and 20B (see also
The back portion 6 may also include a membrane or mesh 25 having a perimeter 26 that is connected to a back frame structure 28. As discussed in more detail below, at least a portion of membrane or mesh 25 has a negative Poisson's ratio such that the membrane comprises an auxetic material. The perimeter 26 of auxetic membrane or mesh 25 may include side portions 26A and 26B that are connected to upright frame portions 30A and 30B, respectively, of back frame structure 28. The auxetic membrane or mesh 25 may also include an upper perimeter portion 26C that is connected to upper horizontal frame portion 32 of back frame structure 32. Auxetic membrane or mesh 25 may further include a lower perimeter portion 26D that is connected to a horizontal lower frame portion 34. As discussed in more detail below, the auxetic membrane or mesh 25 may comprise molded polypropylene or other suitable polymer material. Furthermore, the auxetic membrane or mesh 25 may be integrally formed (e.g. molded) with the back frame structure 28 to form a one-piece molded polypropylene structure. Alternatively, the mesh 25 and frame structure 28 may be integrally formed from other suitable materials. Also, as discussed in more detail below in connection with
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The high pressure regions 44 of auxetic membrane or mesh 25 may be configured to provide additional flexibility or compliance to increase user comfort. Specifically, one or more of the links 40A-40F of the auxetic cells 38 within the high pressure region 44 may have reduced width or thickness to provide increased flexibility/compliance in the high pressure region 44. For example, the links 40A-40F outside of high pressure region 44 may have a square cross-sectional shape with a width of 0.100 inches and a thickness of 0.100 inches, whereas the links 40A-40F inside region 44 may have reduced (equal) width and thickness (e.g. 0.050 inches). An example of a membrane/mesh 25C having variable link thickness/width is shown in
In a preferred embodiment, the auxetic membrane or mesh 25 comprises a one-piece molded polymer member. For example, the auxetic membrane or mesh 25 may comprise molded polypropylene or other suitable material. The auxetic membrane or mesh 25 may be configured to provide increased compliance/flexibility as required for a particular chair configuration to thereby provide a cushioning affect that may be similar to conventional padded chair support structures. The use of a molded polymer membrane or mesh provides a support surface that has significantly reduced cost and complexity relative to conventional padded user support surfaces. Still further, as discussed above, the auxetic membrane or mesh 25 may provide increased compliance/flexibility in certain areas or regions as required to provide increased comfort for a seated user. The compliance of the auxetic membrane or mesh 25 may optionally be controlled in specific regions to provide flexibility/compliance that is similar to the compliance of conventional padded supports/cushions. Additional regions such as upper back region 48 (
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The mesh or membrane 170 includes an edge portion 172 that may comprise solid sheet-like material of substantially uniform thickness having an outer edge 174 that is received within a recessed region of frame 167 to provide a smooth upper surface. The mesh or membrane 170 also includes a plurality of auxetic cells 186 having a boarder 173 where the auxetic cells 186 transition to the solid edge portion 172. The regions of mesh or membrane 170 inside of the edge or border 173 have increased compliance or flexibility relative to the solid edge portion 172. The mesh or membrane 170 may be mounted to frame 167 as shown in
The mesh or membrane 170 includes high pressure zones or regions 184A and 184B. The individual links forming the auxetic cells 186A within the high pressure areas 184A and 184B have reduced thickness and/or width relative to the auxetic cells 186B outside of the high pressure zones or areas 184A and 184B. In the illustrated example, the high pressure zones or areas 184A and 184B generally correspond to the tuberosity of the ischium (buttocks) of a seated user. The mesh or membrane 170 also includes auxetic cells or patterns 186C and 186D that extend forwardly towards a front edge 188 of the user support 165. The auxetic cells 186C and 186D provide increased flexibility/compliance in the region of a user's thighs.
The user support 165 may further include elongated high pressure zones 184C and 184D corresponding to a user's thighs. The high pressure zones 184C and 184D may also include auxetic cells in which the width and/or thickness of the individual links forming the cells is reduced to provide increased compliance and user comfort. A central region or area 190 may include auxetic cells in which the individual links have increased width and/or thickness to provide additional stiffness. As discussed above, the shape and/or size of the high pressure zones of a particular user support 165 may be configured as required to provide user comfort. In general, pressure maps (not shown) may be developed utilizing a solid sheet of material, and the pressure maps may be utilized to provide varying degrees of compliance/flexibility. Also, the user support 165 may utilize auxetic cells having variable geometries as discussed above in connection with
An auxetic membrane 112 according to another aspect of the present invention is shown in
An auxetic membrane 118 according to another aspect of the present invention is shown in
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It will be understood that the features of the different embodiments shown and described in connection with
The auxetic mesh/membrane of the present invention may be utilized in connection with a variety of user support surfaces, including generally upright back supports, generally horizontal seat supports, and in other support structures.
Also, the auxetic user support surfaces/membranes of the present invention may be utilized in connection with various seating units and articles of furniture in addition to the chairs of
It is also to be understood that variations and modifications can be made on the aforementioned structures and methods without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.
Claims
1. A seating unit comprising:
- a lower portion that is configured to support the seating unit;
- a seating structure supported by the lower portion, wherein the seating structure includes a generally horizontal seat portion and a generally upright back portion, wherein at least one of the seat portion and the back portion includes frame portions defining a space therebetween and a flexible polymer membrane extending in first and second directions across the space, and wherein the polymer membrane is connected to the frame portions to define a user support surface, wherein at least a portion of the polymer membrane comprises an auxetic material having a negative Poisson's ratio whereby stretching of the auxetic portion of the polymer membrane in at least one of the first and second directions tends to cause the polymer membrane to expand in the other of the first and second directions.
2. The seating unit of claim 1, wherein:
- the user support surface defines opposite edge portions adjacent to the frame portions, and at least one high pressure region that is spaced apart from the opposite edge portions, and wherein the polymer membrane is significantly more flexible at the high pressure region than it is at the opposite edge portions of the user support surface.
3. The seating unit of claim 2, wherein:
- the polymer membrane defines a region outside of the high pressure region having a first thickness, and a second thickness in the high pressure region that is significantly less than the first thickness.
4. The seating unit of claim 2, wherein:
- the polymer membrane comprises a polymer mesh having a plurality of links that are interconnected to form a pattern extending radially outwardly in a plurality of radial directions from a central portion of the high pressure region, and wherein stretching of the polymer mesh in the radial directions or in directions transverse to the radial directions tends to cause expansion of the polymer mesh in the other of the radial directions and the directions that are transverse to the radial directions.
5. The seating unit of claim 2, wherein:
- the polymer membrane comprises a mesh having a plurality of links that are interconnected to form a pattern, and wherein the pattern is non-uniform to provide increased flexibility in the high pressure region.
6. The seating unit of claim 1, wherein:
- the polymer membrane comprises a mesh having a central portion including a plurality of openings defining a plurality of auxetic cells;
- the polymer membrane includes an integral ring having an outer perimeter and an inner boundary adjacent outermost ones of the openings defining the auxetic cells, wherein the ring defines a width between the outer perimeter and the inner boundary, and wherein the width is non-uniform.
7. The seating unit of claim 1, wherein:
- the flexible polymer membrane comprises polypropylene.
8. The seating unit of claim 1, wherein:
- the frame portions comprise polymer material that is integrally formed with the polymer membrane, and wherein the frame portions are significantly thicker than the polymer membrane and have significantly greater stiffness than the polymer membrane.
9. The seating unit of claim 1, wherein:
- the frame portions are generally upright to define a back frame;
- the back frame includes transverse upper and lower frame portions extending between and interconnecting the upright frame portions to form a perimeter frame defining a central opening; and wherein:
- the flexible polymer membrane includes an upper edge that is spaced apart from the upper frame portion to define a gap therebetween.
10. The seating unit of claim 1, wherein:
- the frame portions include first connecting structures; and wherein:
- the flexible polymer membrane includes integrally formed second connecting structures that engage the first connecting structures and connect the polymer membrane to the frame portions.
11. The seating unit of claim 1, wherein:
- the polymer membrane defines a user support face comprising a plurality of spaced apart support members that are interconnected by folded sheet portions configured to provide an auxetic material.
12. A user support structure comprising:
- a flexible membrane defining front and rear faces and opposite edge portions, the flexible membrane including a high pressure region that is configured to support portions of a user's body when a user's body comes into contact with the high pressure region of the flexible membrane, the flexible membrane defining a lower pressure region adjacent the high pressure region, and wherein the high pressure region and the lower pressure region comprise auxetic material whereby stretching of the flexible membrane in a first direction tends to cause the material to expand in a second direction that is transverse to the first direction and wherein the flexible membrane is significantly more compliant in the high pressure region than the lower pressure region in response to a force that is applied to the front face of the flexible membrane.
13. The user support structure of claim 12, including:
- a pair of spaced apart frame portions extending along the opposite edge portions of the flexible membrane, and wherein the opposite edge portions of the membrane are connected to the frame portions.
14. The user support structure of claim 13, wherein:
- the frame portions extend horizontally and at least a portion of the front face of the flexible membrane faces upwardly to define a seat surface.
15. The user support structure of claim 13, wherein:
- the frame portions extend upwardly and at least a portion of the front face of the flexible membrane faces forwardly to define a back support surface.
16. The user support structure of claim 12, wherein:
- the flexible membrane comprises a polymer mesh.
17. The user support structure of claim 16, wherein:
- the flexible membrane comprises an integrally formed polymer ring defining an outer peripheral edge of the flexible membrane.
18. The user support structure of claim 12, wherein:
- the flexible membrane comprises a plurality of spaced apart support members that are interconnected by folded sheet portions configured to provide an auxetic material.
19. A user support comprising:
- a polymer mesh including a plurality of links forming interconnected auxetic cells, each auxetic cell having a length defined along a first cell axis and a width defined along a second cell axis that is transverse to the first cell axis, and wherein each auxetic cell comprises a plurality of interconnected flexible links configured such that stretching of the auxetic cells along the length of the auxetic cells causes the width of the auxetic cells to increase, and wherein a plurality of the auxetic cells are arranged about a center in a generally circular pattern to provide a region having increased compliance.
20. The user support of claim 19, wherein:
- the polymer mesh comprises polypropylene.
Type: Application
Filed: Apr 29, 2015
Publication Date: Nov 12, 2015
Inventors: David C. Eberlein (Hudsonville, MI), Mark McKenna (East Grand Rapids, MI), Nickolaus William Charles Deevers (Holland, MI), Bruce M. Smith (Grand Rapids, MI), Fredric Biddle (Kalamazoo, MI), Brett Pearson (Rockton, IL)
Application Number: 14/699,648