AU2015349590A1

AU2015349590A1 - A seat cushion

Info

Publication number: AU2015349590A1
Application number: AU2015349590A
Authority: AU
Inventors: Glen DE BONO; Scott Downes; Tony NOUN
Original assignee: GREGORY COMMERCIAL FURNITURE Pty Ltd
Current assignee: GREGORY COMMERCIAL FURNITURE Pty Ltd
Priority date: 2014-11-21
Filing date: 2015-07-31
Publication date: 2017-05-25
Anticipated expiration: 2035-07-31
Also published as: NZ731708A; WO2016077860A1; AU2015349590B2

Abstract

There is disclosed a seat cushion (10), including a forward portion (22) for supporting the upper thighs of a sitter. The forward portion (22) is formed from at least a first resilient material. The seat cushion (10) further includes a rearward portion (24) for supporting the buttocks of the sitter. The rearward portion (24) is formed from a second resilient material, which is relatively softer than the first resilient material. The seat cushion (10) further includes an upwardly open transverse crevice (30) defined between the forward portion (22) and the rearward portion (24). The seat cushion (10) further includes a pair of intermediate portions (38, 40) for supporting the ischial tuberosities of the sitter. The intermediate portions (38, 40) are formed from a third resilient material, which is relatively firmer than the second resilient material. Each intermediate portion (38, 40) is embedded within the forward and rearward portions (22, 24) and extending across the transverse crevice (30). The intermediate portions (38, 40) are laterally spaced apart such that, in use, each intermediate portion (38, 40) is locatable below a respective ischial tuberosity of the sitter.

Description

PCT/AU2015/000455 WO 2016/077860 1

A SEAT CUSHION

Field [0001 ] The present invention relates to a seat cushion.

[0002] The present invention has been developed primarily for use in office chairs. However, it will be appreciated that the invention is not limited to this particular field of use and is also suitable for other types of chairs and seats. For example, car seats, sofas and baby chairs.

Background [0003] Seat cushions are well known and typically used in an office chair to directly support a sitter. As the sitter is often seated in the office chair for prolonged periods of time, especially during work hours, the sitter can experience significant lower back pain and discomfort.

[0004] In an attempt to reduce lower back pain experienced by the sitter, there have been numerous developments in seat cushions that seek to promote correct posture in the sitter. Specifically, known seat cushions have been designed to encourage the lower spine of the sitter to display a natural concave curvature known as lumbar lordosis. However, these known seat cushions do not cater well for ranging body shapes and sizes and therefore often fail to adequately promote correct posture, particularly in heavier sitters. Further, these known seat cushions often exert significant pressure on the thighs of the sitter restricting blood flow and causing discomfort, particularly in lighter sitters.

[0005] In an attempt to reduce discomfort, other known seat cushions have been developed to direct pressure towards the ischial tuberosities of the sitter when seated. Although some pressure is relieved from other parts of the body (e.g. thighs) of the sitter, after prolonged seating, these known seat cushions are still considered too firm and uncomfortable. Further, these known seat cushions generally lack any mechanism to promote correct posture in the sitter.

Object of Invention [0006] It is the object of the present invention to overcome or substantially ameliorate one or more of the above disadvantages, or at least provide a useful alternative. PCT/AU2015/000455 WO 2016/077860 2

Summary of Invention [0007] There is disclosed herein a seat cushion, including: a forward portion for supporting the upper thighs of a sitter, the forward portion being formed from at least a first resilient material; a rearward portion for supporting the buttocks of the sitter, the rearward portion being formed from a second resilient material, which is relatively softer than the first resilient material; an upwardly open transverse crevice defined between the forward portion and the rearward portion; and a pair of intermediate portions for supporting the ischial tuberosities of the sitter, the intermediate portions being formed from a third resilient material, which is relatively firmer than the second resilient material, each intermediate portion being embedded within the forward and rearward portions and extending across the transverse crevice, the intermediate portions being laterally spaced apart such that, in use, each intermediate portion is locatable below a respective ischial tuberosity of the sitter.

[0008] In use, the rearward portion preferably deforms to a greater extent than the forward portion and thereby defines a transverse ridge which substantially resists forward movement of the ischial tuberosities of the sitter.

[0009] Each intermediate portion preferably comprises a forward intermediate portion embedded within the forward portion, a rearward intermediate portion embedded within the rearward portion, an upwardly open transverse intermediate crevice defined between the forward and rearward intermediate portions, and a lower bridge portion connecting the forward and rearward intermediate portions. Each rearward intermediate portion preferably is larger in size than a respective forward intermediate portion. Each forward intermediate portion preferably extends forwardly from a respective transverse intermediate crevice to about half way through the forward portion.

[00010] Each intermediate portion preferably is substantially forwardly and upwardly tapered.

[00011 ] Each intennediate portion preferably is generally ovoid shaped when viewed from the top. PCT/AU2015/000455 WO 2016/077860 3 [00012] Each intermediate portion preferably is generally triangle shaped when viewed from the side.

[00013] An upper layer of the forward portion and an upper layer of the rearward portion preferably extend above the intermediate portions.

[00014] A lower layer of the forward portion and a lower layer of the rearward portion preferably extend below the intermediate portions.

[00015] The transverse crevice preferably is located closer to the rear of the seat cushion than the front of the seat cushion.

[00016] The transverse crevice preferably is located such that a rearward length from the transverse crevice to the rear of the seat cushion is less than 50% of a main length from the front of the seat cushion to the rear of the seat cushion and a forward length from the transverse crevice to the front of the seat cushion is more than 50% of the main length. The transverse crevice preferably is located such that the rearward length is about 40% of the main length and the forward length is about 60% of the main length .

[00017] The transverse crevice preferably extends sidewardly to about 30mm from each side of the seat cushion.

[00018] The third resilient material preferably is firmer than the first resilient material.

[00019] The forward portion preferably is larger in size than the rearward portion.

[00020] The second resilient material preferably comprises foam with a relatively low density.

[00021] The first resilient material preferably comprises foam with a relatively high density. The third resilient material preferably comprises foam with a hi gher density than the foam of the first resilient material. PCT/AU2015/000455 WO 2016/077860 4

Brief Description of Drawings [00022] A preferred embodiment of the invention will be described hereinafter, by way of example only, with reference to the accompanying drawings, wherein: [00023] Figure 1 is a side sectional view of an embodiment of a seat cushion integrated into an office chair with a sitter seated thereon; [00024] Figure 2 is a top perspective view of the seat cushion of Fi gure 1 showing a pair of intermediate portions with one of the intermediate portions removed from forward and rearward portions; and [00025] Figure 3 is a side sectional view of the seat cushion of Figure 1 through one of the intermediate portions.

Description of Embodiments [00026] Figure 1 shows an embodiment of a seat cushion 10 integrated into an office chair 12 with a sitter 14 seated thereon. The office chair 12 has a base assembly 16, an elevated platform 18 and a back rest 20. The seat cushion 10 is attached to the elevated platform 18 such that the seat cushion 10 is slightly declined towards the front.

[00027] As shown in Figures 2 and 3, the seat cushion 10 includes a forward portion 22 and a rearward portion 24 disposed adjacent the forward portion 22. The forward portion 22 is for supporting the upper thighs 26 of the sitter 14. The forward portion 22 is formed from resilient high density polyurethane foam which is uniform in composition, density (60 gram-force) and resiliency. The rearward portion 24 is smaller in size than the forward portion 22 and is for supporting the buttocks 28 of the sitter 14. The rearward portion 24 is formed from resilient low density polyurethane foam which is uniform in composition, density (45 gram-force) and resiliency. The low density polyurethane foam used in the rearward portion 24 is relatively softer than the high density polyurethane foam used in the forward portion 22 allowing the rearward portion 24 to be able to deform to a greater extent than the forward portion 22 in use.

[00028] The seat cushion 10 further includes an upwardly open transverse crevice 30 defined between the forward portion 22 and the rearward portion 24. The transverse crevice 30 is PCT/AU2015/000455 WO 2016/077860 5 triangular in shape when viewed from the side. The transverse crevice 30 extends sidewardly to and terminates about 30mm from each side of the seat cushion 10. The transverse crevice 30 is located such that a rearward length 32 from the transverse crevice 30 to the rear of the seat cushion 10 is about 40% of a main length 34 from the front of the seat cushion 10 to the rear of the seat cushion 10 and a forward length 36 from the transverse crevice 30 to the front of the seat cushion 10 is about 60% of the main length 34.

[00029] The seat cushion 10 further includes a pair of intermediate portions 38, 40 for supporting the ischial tuberosities 42 of the sitter 14. The intermediate portions 38, 40 are fonned from high density polyurethane foam which is uniform in composition, density (80 gram-force) and resiliency. The high density foam polyurethane foam used in the intermediate portions 38, 40 is of a higher density than the high density foam polyurethane foam used in the forward portion 22. As a result, the intermediate portions 38, 40 are relatively firmer than the forward and rearward portions 22, 24.

[00030] Each intermediate portion 38, 40 is embedded within the forward and rearward portions 22, 24 and extends across the transverse crevice 30. Each intermediate portion 38, 40 comprises a forward intennediate portion 44, a rearward intermediate portion 46, an upwardly open transverse intermediate crevice 48 defined between the forward and rearward intermediate portions 44, 46, and a lower bridge portion 50. Each forward intermediate portion 44 is embedded within the forward portion 22 and extends forwardly from a respective transverse intennediate crevice 48 to about half way through the forward portion 22. An upper layer 52 of the forward portion 22 extends above each forward intermediate portion 44 and a lower layer 54 of the forward portion 22 extends below each forward intermediate portion 44. Each rearward intermediate portion 46 is substantially larger in size than a respective forward intennediate portion 44 and embedded within the rearward portion 24. An upper layer 56 of the rearward portion 24 extends above each rearward intermediate portion 46 and a lower layer 58 of the rearward portion 24 extends below each rearward intermediate portion 46. Each transverse intennediate crevice 48 is aligned sidewardly with the other transverse intennediate crevice 48 and aligned upwardly with the transverse crevice 30. As best shown in Figure 3, this alignment allows the transverse crevice 30 and the transverse intermediate crevices 48 to substantially act as a single crevice. Each lower bridge portion 50 is located under a respective transverse intermediate crevice 48 and connects a respective forward intermediate portion 44 and a respective rearward intermediate portion 46. PCT/AU2015/000455 WO 2016/077860 6 [00031] The intermediate portions 38, 40 are laterally apart such that, when the sitter 14 is seated as shown in Figure 1, each rearward intermediate portion 46 locates below a respective ischial tuberosity 42 of the sitter 14 and each forward intermediate portion 44 locates below a respective upper thigh 26 of the sitter 14. As best shown in Figures 2 and 3, each intermediate portion 38, 40 is substantially ovoid in shape when viewed from the top and substantially triangular in shape when viewed from the side. Each intermediate portion 38, 40 is forwardly and upwardly tapered such that its forward intermediate portion 44 is substantially in the shape of a right-angled triangle when viewed from the side with its hypotenuse extending forwardly and upwardly from its transverse intermediate crevice 48. Further, each rearward intermediate portion 46 is substantially frustoconical in shape with a substantially vertical forward side.

[00032] Although not shown, it will be appreciated that the seat cushion 10 will be upholstered with an appropriate seat cover.

[00033] The operation of the seat cushion 10 will now be described.

[00034] As shown in Figure 1, when the sitter 14 is seated on the chair 12, the forward portion 22 supports the upper thighs 26 of the sitter 14 and the rearward portion 24 supports the buttocks 28 of the sitter 14.

[00035] Each ischial tuberosity 42 of the sitter 14 is supported by a combination of the upper and lower layers 56, 58 of the rearward portion 24 and a respective rearward intermediate portion 46. This combinati on all ows the ischial tuberosities 42 of the sitter 14 to be firmly supported compared to other parts of the buttocks 28 and the pressure experienced by the buttocks 26 of the sitter 14 to be mostly directed towards the ischial tuberosities 42. It will be appreciated that, although the ischial tuberosities 42 are finnly supported, the sitter 42 experiences relative comfort as the ischial tuberosities 42 directly contact the upper layer 56 of the rearward portion 24 and the rearward intermediate portions 46 are supported by the lower layer 58 of the rearward portion 24.

[00036] In use, given that the rearward portion 24 deforms to a greater extent than the forward portion 22, the transverse crevice 30 and the transverse intermediate crevices 48 allow the upper layer 56 of the rearward portion to depress to a greater extent than the upper layer 52 of the forward porti on 22. This difference causes the formation a transverse ridge on the back of the forward portion 22 such that it is located in front of the ischial tuberosities 42 of the sitter 14. It PCT/AU2015/000455 WO 2016/077860 7 will be appreciated that the transverse ridge provides a support for the ischial tuberosities 42 of the sitter 42 to resist the forward movement thereof.

[00037] Due to the shape (i.e. forward reduction in thickness), each forward intermediate portion 44 provides a gradual decrease in firmness in the forward direction experienced by a respective upper thigh 26 of the sitter 14. This allows the pressure experienced by the upper thigh 26 to gradually decrease in the forward direction. It will be appreciated, since the upper thighs 26 directly contact the upper layer 52 of the forward portion 22 and the forward intermediate portions 44 are supported by the lower layer 54 of the forward portion 22, the upper thighs 26 are supported in relative comfort.

[00038] In use, the rearward intermediate portions 46 of the intermediate portions 38, 40 advantageously allow the ischial tuberosities 42 of the sitter 14 to be firmly supported such that the pressure experienced by the buttocks 26 of the sitter is directed towards the ischial tuberosities 42. This provides substantial comfort for the sitter 14 as pressure is concentrated on the ischial tuberosities 42 of th e sitter 14 and substantially reduced on other parts of the buttocks 26. More particularly, the relatively softer upper layers 52, 56 directly contact the upper thighs 26 and ischial tuberosities 42 of the sitter 14, respectively, rather than the relatively finner intermediate portions 38, 40. This enhances the comfort level of the sitter 14 as the relatively softer upper layers 52, 56 are more compliant than the intermediate portions 38, 40. Similarly, the relatively softer lower layers 54, 58 directly contact the elevated platform 18 of the chair 12 supporting the intermediate portions 38, 40. This substantially increases the comfort level experienced by the sitter 14 as substantial pressure is absorbed by the more compliant lower layers 54, 58.

[00039] In use, the forward intermediate portions 44 of the intermediate portions 38, 40 advantageously allow the pressure to gradually decrease from the back to the front of the upper thighs 26 of the sitter 14. This distribution of pressure across the upper thighs 26 promotes blood circulation therein and comfort levels, especially for sitters of relatively light wei ght.

[00040] The formation of the transverse ridge advantageously substantially resists forward movement of the ischial tuberosities 42 of the sitter 14 and thereby promotes correct posture in the sitter 14. More particularly, the location of the transverse crevice 30 and transverse PCT/AU2015/000455 WO 2016/077860 8 intermediate crevices 48 allows the seat cushion 10 to promote correct posture in the sitter 14 of varying body size and shape, especially for sitters of relatively heavy weight.

[00041] As the transverse crevice 30 extends sidewardly to and terminates about 30mm from each side of the seat cushion 10, the durability of the seat cushion 10 and the seat cover is advantageously increased.

[00042] Although the invention has been described with reference to a preferred embodiment, it will be appreciated by a person skilled in the art that the invention may be embodied in many other forms.

Claims

1. A seat cushion, including: a forward portion for supporting the upper thighs of a sitter, the forward portion being formed from at least a first resilient material; a rearward portion for supporting the buttocks of the sitter, the rearward portion being formed from a second resilient material, which is relatively softer than the first resilient material; an upwardly open transverse crevice defined between the forward portion and the rearward portion; and a pair of intermediate portions for supporting the ischial tuberosities of the sitter, the intennediate portions being formed from a third resilient material, which is relatively firmer than the second resilient material, each intermediate portion being embedded within the forward and rearward portions and extending across the transverse crevice, the intermediate portions being laterally spaced apart such that, in use, each intennediate portion is locatable below a respective ischial tuberosity of the sitter.

2. The seat cushion according to claim 1, wherein, in use, the rearward portion deforms to a greater extent than the forward portion and thereby defines a transverse ridge which substantially resists forward movement of the ischial tuberosities of the sitter.

3. The seat cushion according to claim 1 or 2, wherein each intermediate portion comprises a forward intermediate portion embedded within the forward portion, a rearward intermediate portion embedded within the rearward portion, an upwardly open transverse intermediate crevice defined between the forward and rearward intermediate portions, and a lower bridge portion connecting the forward and rearward intennediate portions.

4. The seat cushion according to claim 3, wherein each rearward intermediate portion is larger in size than a respective forward intennediate portion.

5. The seat cushion according to claim 3 or 4, wherein each forward intennediate portion extends forwardly from a respective transverse intennediate crevice to about half way through the forward portion.

6. The seat cushion according to any one of the preceding claims, wherein each intermediate portion is substantially forwardly and upwardly tapered.

7. The seat cushion according to any one of the preceding claims, wherein each intermediate portion is generally ovoid shaped when viewed from the top.

8. The seat cushion according to any one of the preceding claims, wherein each intennediate portion is generally triangle shaped when viewed from the side.

9. The seat cushion according to any one of the preceding claims, wherein an upper layer of the forward portion and an upper layer of the rearward portion extend above the intermediate portions.

10. The seat cushion according to any one of the preceding claims, wherein a lower layer of the forward portion and a lower layer of the rearward portion extend below the intermediate portions.

11. The seat cushion according to any one of the preceding claims, wherein the transverse crevice is located closer to the rear of the seat cushion than the front of the seat cushion.

12. The seat cushion according to any one of the preceding claims, wherein the transverse crevice is located such that a rearward length from the transverse crevice to the rear of the seat cushion is less than 50% of a main length from the front of the seat cushion to the rear of the seat cushion and a forw ard length from the transverse crevice to the front of the seat cushion is more than 50% of the main length.

13. The seat cushion according to claim 12, wherein the transverse crevice is located such that the rearward length is about 40% of the main length and the forward length is about 60% of the main length.

14. The seat cushion according to any one of the preceding claims, wherein the transverse crevice extends sidewardly to about 30mm from each side of the seat cushion.

15. The seat cushion according to any one of the preceding claims, wherein the third resilient material is firmer than the first resilient material.

16. The seat cushion according to any one of the preceding claims, wherein the forward portion is larger in size than the rearward portion.

17. The seat cushion according to any one of the preceding claims, wherein the second resilient material comprises foam with a relatively low density.

18. The seat cushion according to any one of the preceding claims, wherein the first resilient material comprises foam with a relatively high density.

19. The seat cushion according to claim 18, wherein the third resilient material comprises foam with a higher density than the foam of the first resilient material.