GB2539792A - Improvements in or relating to posture - Google Patents

Abstract

Back support cushion 30 that comprises first 31 and second 32 generally planar main surfaces and having top 36, bottom 35 and first 33 and second 34 side surfaces; wherein the first main surface 31 has a profile of one half of a teardrop (or pear) section, having a curvilinear apex positioned between 50 and 90mm from the bottom surface of the cushion. The cushion is formed from first (38, Fig 4) and second (39, Fig 4) regions, wherein the material of the first region (38) or teardrop section being a conformable material having an hardness value in the range of 175 265lbs and the material of the second region (39) providing lateral rigidity to the cushion and having an hardness value in the range of 175 265lbs and density of 35 120Kgm-3. The cushion may be made from polyurethane memory foam and can include a rigid plastic, wooden or metallic insert within the second region (39).

Description

Improvements in or relating to Posture

Field of Invention

[0001] The present invention relates to cushions for back support in general and to improve posture whilst sitting and relates to the provision of back supports for use with chairs, seats, sofas and the like. In particular, the present invention especially relates to a back support cushion that is comfortable and convenient to use with respect to an armchair, sofa, a wheelchair or a day chair.

Background to the Invention

[0002] Although a human being is bipedal and walks, while in a vertical position, the spine is not relaxed and strain free unless laid in a horizontal position where the forces of gravity, particularly across the vertebral links, are minimal. Supports for various sections of the spinal column, cervical, thoracic and lumbar have been proposed, particularly for seated people, but no complete support is available for the whole spinal structure. Sustained mechanical loads applied to a body surface, as occurs during prolonged sitting or lying in one position, tends to cause damage in the weight-bearing soft tissues due to the cellular distortion and secondary ischemic effects, as blood vessels are obstructed and ligamentous creep causes instability of the spine and discs. The onset of these damage pathways is normally accompanied by a sense of pain, which induces the individual to shift his body weight away from the currently weight-bearing body surface to another body surface.

[0003] When a person is not mobile in a house or an office and neither supine nor standing then they will typically be sitting, either at a seat, stool, bench or sofa. Nonetheless, the weight of the upper body will still be acting upon the pelvic bone, commonly referred to as the hip bone.

The pelvic bone is a large flat bone, constricted in the centre and expanded above and below, and is formed by three bones, namely the ilium, the ischium and the pubis. Whilst at birth, these three component bones are separated by cartilage, following puberty, the three bones will have fused together, and by the age of twenty-five years they will have ossified. The two hip bones join each other at the pubic symphysis; together with the sacrum and coccyx, the hip bones form the pelvis.

[0004] The human vertebral column consists of thirty-three vertebrae, which are classically grouped into different regions, which correspond to the curves of the spinal column, specifically, the cervical spine, thoracic spine, lumbar spine, sacrum and coccyx. The articulating vertebrae are named according to their region of the spine, with seven cervical vertebrae, twelve thoracic vertebrae and five lumbar vertebrae. Vertebrae in these regions are essentially alike, with minor variation. The vertebral column surrounds the spinal cord, which travels within the spinal canal, formed from a central hole within each vertebra. The spinal cord is part of the central nervous system that supplies nerves and receives information from the peripheral nervous system within the body.

[0005] For those with back problems the act of sitting does not necessarily reduce such problems, although the use of a seat with armrests or similar supports may assist in the reduction of pressure arising through transfer of weight through the spine. Existing chair backrests may seek to take into account comfort requirements of users by the provision of one or more soft cushions, but do not tend to take into account the requirements of any apparently ancillary matters such as ergonomics or health care. A chair backrest or cushion is, accordingly, typically a generally flat or curved plate-like structure. Indeed, it appears that the design of a back support for a chair, sofa, etc. appears to be unduly influenced by the vagaries of fashion. For example, for many people, a living room furniture such as an armchair or sofa is a significant purchase to be made for their home, and there will tend to be a balance between aesthetics, how it fits into the home decor and finding the best price and best quality. One factor in determining both price and quality is the way the chair or sofa has been constructed. Whilst one can have superior methods of construction, especially in the construction of the frame and in the seat cushions, such as the use of eight-way hand-tied springs which allow the springs to move independently and can provide good support, less expensive methods of manufacture such as the use of sinuous springs or web suspension are more frequently employed and typically are used in pieces of furniture that sit lower to the ground.

[0006] It is ordinarily regarded that a cushion that employs feathers, notably goose down, provide the best filling for comfort in a cushion, even though 1000/0 down filling can shift over time and needs frequent fluffing, it is expensive. Cheaper alternatives employ down to surround a foam core. Batting is another traditional cushion and quilt filling placed between two pieces of fabric to form the quilt and presently is conveniently manufactured from cotton, polyester and wool. The batt material or layers of batts are commonly processed using one of two different techniques, bonding or needle punch and in some cases both. Bonded batts usually use an acrylic based resin, which is sprayed on during manufacture to bond the fibres together to stabilize and prevent bearding. Whatever the actual the type of batting that is employed, however, the provision of actual support for those tends to be disregarded. Notwithstanding the above, plastics foam is the most common stuffing material.

[0007] For a typical sofa and many armchairs, the chair is formed by the use of a base frame, which supports a number of separate cushions. The cushion may be fitted -so that it conforms to a particular inside form of the chair or loose such that one can fluff and otherwise create a support that is believed to be comfortable -at least when initially placed.

[0008] It is interesting to note that sofa buying guides and the like will make reference to the area of the room to be filled, the aspects of the room available when placed, with regard to positions of tables and other furniture, a window and proximity to any audio/visual equipment. Little regard appears to be had to the specific dimensions of the intended occupants; most furniture is manufactured to standard measurements. Little regard is made to the actual specific dimensions for those who intend to use the furniture; the distance from the front of a sofa or chair seat cushion to the rear being made too large, with the logic being that any excess space can be occupied by cushions.

[0009] Those who are short in the leg, or with limited mobility will tend not to be optimally positioned, which will exacerbate any issues of back pain as discussed above. A common scenario will be that an elderly or infirm visitor at a home who is invited to the lounge. Although the armchair or sofa may of good quality, the armchair or sofa is actually uncomfortable to sit in, and the visitor will opt to sit in a carver chair at a table, or to utilise a supportive kitchen chair. This situation is repeated in a number of environments. For example, in a family a mother has back pain. A bolster cushion may be employed, but the person with the back pain does not want to appear different and when others are around does not want to appear different and does not utilise what would be good for the mother. Equally the bolster cushion may be employed by another member of the family.

[0010] In another example, many people work for a long time sitting in an office chair, and this can lead to spinal deformation over time. With regard to work-related illnesses, one of the most common is the lumbar disc. Lumbar disc herniations occur in the lower back, most often between the fourth and fifth lumbar vertebral bodies or between the fifth and the sacrum. Symptoms can affect the lower back, buttocks, thigh, anal/genital region and may radiate into the foot and/or toe. Whilst it is known that the use of appropriate cushions can provide comfort and prevention or treatment of lumbar disc herniation. However, the use of appropriate cushions is not necessarily easily enabled; either they cannot easily be deployed or convenient to use and, in the home, especially, may not conform with decor.

[0011] The furniture market with respect to seating is diverse and unregulated. Dimensions of seating varying widely across the globe with regional differences and with fashion. Applicants have determined that the dimensions of known furniture cannot be relied upon to correctly address the ergonomic needs of the user. It is noted by Kroemer et al, 1994, that lumbar supports are designed 'depending on the designers' assumptions about body size and body posture'. Therefore, detailed ergonomics research was carried out to determine the correct dimensions and requirements of an ideal, free standing back support. General recommendations can be made about the incline of the back support, but this is often not possible to change on a sofa as it is on an office chair. It has widely thought that sofa backs recline at an angle of 90° to the horizontal, although research by "Futon Life" in 2005 has indicated that the average incline of a sofa is 1130, which has been corroborated by a similar finding -an angle of 1150 -by the seating designer and manufacturer Herman Miller. Incidentally, this 113° angle of incline is in keeping with the range of 110-120° recommended by the British Standards Institute (1980), which also indicated that the overall shape of the back support should 'be slightly convex'. Notwithstanding this, furniture in the design of chairs, sofas and similar -particularly in relation to back support -has not progressed with regard to those who suffer from back pain. Presently, one sofa manufacturer in the United Kingdom promotes three cushion filling options, with a first filling being fibre for a soft, squishy feel; a foam filling core for balanced softness and support in a medium option and full foam filling for a supportive, slightly springy feel as a final, firm option.

[0012] There are a number of seat squab and chair back rests that seek to increase support and consequently comfort. GB2414178 provides a pillow, cushion, bolster or mattress, made up of first and second, respectively main and insert sections that can interlock together and separate when necessary. The main section defines a cavity or placement area into which, onto which or under which the insert section fits. Different insert sections can be used with different main sections or they can be used independently. This teaching provides a variety of insert sections, so that the user can get the best possible comfort and support as well as therapeutic and medical benefits. GR20070100048 teaches of a pillow having the shape of a rectangular a parallelogram and is composed of two separate differently-dimensioned pillows sewn together in such a way that the bigger pillow encloses the smaller one for forming both a unified ensemble. Both pillow's parts are different in toughness due either to the density of the filling material or to the different filling material in use. U52015096124 teaches of a support device including a substantially cylindrical body having a first elongated body portion and a second elongated body portion, each body portion having a generally semi-cylindrical shape, the two body portions interfacing along a longitudinal plane. An inner cavity is disposed on an inner surface of each body portion, dimensioned for receiving at least one removable and adjustable insert, such that each insert is adjustable and positionable for conforming to a profile of a body of a user.

OBJECT TO THE INVENTION

[0013] The present invention seeks to provide a realistic and inexpensive solution to the problems discussed above. The present invention further seeks to provide a cushion that can be easily and simply deployed and provides suitable back support for considerable numbers of people whilst sitting.

STATEMENT OF THE INVENTION

[0014] In accordance with a first aspect of the invention, there is provided a back support cushion comprising first and second generally planar main surfaces and having top, bottom and first and second side surfaces; wherein the first main surface has a profile of one half of a teardrop (or pear) section, having a curvilinear apex defined by the teardrop section positioned between 50 and 90mm from the bottom surface of the cushion, wherein the cushion comprising first and second regions, wherein the material of the first region or teardrop section being a conformable material having hardness value in the range of 175 -2651bs and the conformable material of the second region providing lateral rigidity to the cushion and having a hardness value in the range of -265Ibs and a density of 35-120Kgm-3. The foam having a vertically split teardrop apex profile, in use, when placed upon a backrest of a chair, seat or sofa, conveniently within a cushion case, will be positioned against the third to fifth lumbar vertebrae of a user of the chair, seat or sofa, whereby to improve the posture and reduce pain from bearing weight upon the lower vertebrae.

[0015] Conveniently, the first and second conformable materials comprise foam materials, such as a polyurethane foam, which foams are fastened to each other about a common interface. The two sections are preferably fastened to each other by one of an adhesive or solvent. The density of the foam for the first region is preferably in the range 25 -65Kgm-3, with particularly good results being provided with foams having respective densities of 30 -45Kgm-3 (especially 32 -34Kgm-3) and 95Kgm-3 for materials of the first and second regions.

[0016] In an alternative configuration, two regions of the back support cushion are defined by a single type of foam, with the second region having an insert to provide lateral stability. For example, the second region has lateral channels defined therein whereby to enable inserts to be placed therein wherein the inserts are one of rigid plastics, wooden or metallic members.

[0017] In accordance with another aspect of the invention, the back support cushion can be provided with a cover, with the curvilinear apex of the cushion being formed such that the distance of the curvilinear apex is between 50 and 90mm from the base of the cushion with cover. This enables the back support cover to appear to be an ordinary cushion, whereby so as not to detract from similar cushions arranged, for example, as part of a set of lounge cushions. Any padding is conveniently retained in place by stitching or otherwise, to prevent sagging, the padding enabling the cushion to appear to be similar to other cushions of a set, but being arranged with the apex-shaped foam provides a greater degree of comfort, the padding being easily compressed whereby only so as not to detract from the function of the invention.

[0018] In accordance with an alternative aspect of the invention, the cushion is incorporated into a pre-existing cushion associated with an item of furniture, the item of furniture having a seat squab and a back rest, wherein the back support cushion is placed within or in front of the back rest of the item of furniture, wherein the curvilinear apex of the cushion being positioned such that the curvilinear apex is between 50 and 90mm from the base of the seat.

[0019] The present invention thus provides a cushion that can improve back support for those with back pain and or sedentary jobs where issues with back pain are likely to arise, the cushion being for use with or to replace a pre-existing back cushion of a chair, sofa, wheelchair or day chair.

Brief Description of the Figures

[0020] For a better understanding of the present invention, reference will now be made, by way of example only, to the Figures as shown in the accompanying drawing sheets, wherein:-Figure 1 shows a section through a first known pillow or mattress; Figure 2 shows a perspective view of a second known pillow; Figure 3 show a first embodiment of a back support cushion 30 in accordance with the invention in perspective view from the front; Figure 4 shows a view from above of the first embodiment; Figure 5 shows a plan view of the first embodiment cushion; Figure 6 shows a side view of the first embodiment cushion; Figure 7 shows a perspective view of a second embodiment; Figure 8 shows a cushion of the second embodiment; Figure 9 shows a side view of a third embodiment; Figure 10 shows a perspective view of the third embodiment being placed within a padded cushion cover; and, Figure 11 shows the resulting third embodiment enclosed within a cushion cover.

Detailed description of the Preferred Embodiments

[0021] There will now be described, by way of example only, the best mode contemplated by the inventor for carrying out the present invention. In the following description, numerous specific details are set out in order to provide a complete understanding to the present invention. It will be apparent to those skilled in the art, that the present invention may be put into practice with variations of the specific.

Referring now to figures 3 and 4 there is shown a first embodiment of a back support cushion 30 in accordance with the invention, in perspective view, from the front as would be positioned upon a seat squab, with the rear face abutting a seat back. Back support cushion 30 is shown having two generally rectangular front and rear faces 31, 32, with sides 33, 34 having a general profile determined by the front face, in the form of a vertically split teardrop curve. The lower and upper edges are indicated at 35 and 36, respectively.

[0022] With particular reference to Figure 4, which is a view of the cushion from above, the two foam regions can be easily seen. The cushion comprises first and second regions 38, 39, with the first region extending from the front face 31 axially towards the second face having a value of its hardness in the range of 175 to 265Ibs, with the second region being stiffer and providing a lateral rigidity to the cushion. The dimensions of this embodiment for a slim profile cushion, conveniently for insertion within a 45cm x 45cm cover -a common size of cushion -are 42cm x 42cm, although the width may be further reduced when the distance from the rear face to the apex is increased; the maximum depth (thickness) of the foam cushion is 50mm -apex peak to rear face of cushion, with the second region of foam -which provides lateral stiffness -being formed from a distinct foam. Satisfactory results have been achieved with many foam products, especially those having i) a density of 42 Kgm-3 with a Hardness 215 -265Ibs; ii) a density of 39Kgrn-3 with a hardness 195Ibs; and iii) a density of 33Kgm-3 with a hardness 190Ibs.

[0023] It has been determined that memory foam is useful in this application, noting that the memory function of a foam is independent of its density per se, but that it is formed as a foam but with additional chemicals to increase its viscosity and density. It is often referred to as "viscoelastic" polyurethane foam, or low-resilience polyurethane foam. Higher-density memory foam softens in reaction to body heat, allowing it to mould to a warm body in a few minutes. It will be appreciated that memory has widespread acceptance in medical situations, especially where a patient is immobile for long periods of time.

[0024] Applicants have determined that the second region of foam can 5 comprise the same type of foam with lateral members defined within longitudinal apertures (and spaced from the extreme edge of the cushion) or be made from a distinct type of foam, with the foam types being glued together by an appropriate adhesive. Specifically, Applicants have determined that the second foam can be formed from a grade 50 foam, such as a grade 50 "chip" foam, which is both a widely available and a low-cost type of foam, commonly referred to as "mixed recycled polyurethane foam" and can have a density in the range of 35 -120Kgm 3, although it has been determined that a more preferable density limit is 95kgm-3with a 6Ib hardness rating has been found to be particularly suitable. Hardness/firmness is determined by its Indentation Load Deflection (ILD) rating. ILD measures the amount of force, in pounds, required to indent a 50" inch disc into a 15"x15"x4" viscoelastic foam sample and make a 1" indentation. For example, 14 ILD means it would take 14Ib to make a 1" indentation in the foam.

[0025] Referring now to figures 4 and 5, the first embodiment is shown from the front and from one side, respectively. Apex region 40 is indicated as a horizontally extending region, since this corresponds with the average height of the third -fifth vertebrae of the human spine. The curved pear shape also allows the apex region to generally correspond with such vertebrae, irrespective of the particular angle of a backrest of a chair or sofa with respect to which the cushion is to be used, noting that it is common for seat rests to be up to 300 to the vertical. By providing such a "thin" cushion from back to front, with the important characteristic of supporting the third to fifth lumbar vertebrae, the present invention provides a back support cushion that can be inserted within pre-existing cushion or provide a discrete thin cushion that can be relatively simply and inconspicuously employed by those who suffer from back problems but who do not want to allow their suffering to be brought to the attention of all those around. Indeed, a house-holder could have several of these cushions whereby those who need the cushion can benefit from the cushion, even though a "normal" sitting place for the householder with a back problem is taken up by a visitor to the home.

[0026] It will be appreciated that for certain circumstances, for example, where the cushion is to become an integral part of a chair or sofa, then the back support of the invention needs to have the apex of the vertically split teardrop or pear shape part of the front cushion to be positioned in the range of 50 -90mm from the seat squab base (taking into account movement due to compression of the seat squab upon an occupier of the seat) and also that there is sufficient room for the person intended to benefit from the sofa or chair with back support. Referring, in particular to Figure 7, there is shown a sofa 70 having a back rest cushion 71, the area indicated by reference numeral 71 defines an area where the present invention is integrated into the back rest. It will be appreciated that the sofa will need to be sized for its occupant, which could mean that the integral or dedicated sofa/chair back rest or cushion extends beyond the line of the other sofa back cushion, in a true tailor-made example. Although it is to be expected that this would be unusual since it would bring the condition of the back sufferer to the attention of others, which is contrary to the provision of a separate apparently ordinary cushion as taught with respect to the first embodiment. Figure 8 shows a cushion insert in profile, which shows a far deeper second region of the cushion, which might be truncated to reduce any liability to become too deformable, whereby to provide a back support sofa without the necessity of separate cushions.

[0027] Polyurethane foam is preferably selected as a suitable foam material given that it already has widespread use in the construction of commercial and domestic furniture and is readily available with specific resilience characteristics, with known fire-risk properties. Polyurethane formulations cover an extremely wide range of stiffness, hardness, and densities. It has previously been considered that the foam should have a Young's modulus of the order of 20KPa to be comparable with human soft tissue, per Mills, 2007. However, it has been found that the young's modulus of the foam should approach the value of 26 to 30 KPa, whereby to provide sufficient resilience to movement of the third -fifth vertebrae, whereby to provide the comfort and support.

[0028] Cushions in accordance with the invention can be made by a variety of machines; the cutting of the profile being typically programmed into a cutting machine by various programming methods. Nonetheless, in terms of Cartesian coordinates the pear shape curve can be provided by the following equation: r2 = (x2 ± y2)(1 ± 2x + 5x2 6x3 +611 ± 4x5 ± x6 -3y2 -2xv +8x2y2 + 8x3y2 + 3x4y2 + 2y4 + 4xy4 + 3x2y4 + y6) [0029] Due to the unregulated nature of the market, dimension from existing solutions could not be relied upon to correctly address the ergonomic needs of the user. It is noted by Kroemer et al, 1994, that lumbar supports are designed 'depending on the designers' assumptions about body size and body posture'. Therefore, detailed ergonomics research was carried out to determine the correct dimensions and requirements of an ideal, free standing back support.

[0030] Referring now to Figures 9 and 10, there is shown a further embodiment of the invention, wherein the foam cushion is placed within a cover 45. The cover is shown in Figure 11; the cover optionally being provided with easily compressible padding, typically comprising feather down or polyester fibre (spun). The use of such padding enables the cushion to be inserted in a normal cushion, or for example, to replace a known cushion having a design, as part of a lounge suite. That is to say a back support in accordance with the present invention can be indistinguishable visually from the cushions associated with a suite of furniture. Conveniently, the cover includes three pockets as seen from the outside and indicated as 46i, 46ii and 46ffi, defined by stitches 47, the stitches maintaining the padding in place. The padding can be of the order of 1 -15cm thick, more typically 2 -6cm thick; noting that if it is too thick and not sufficiently compressible, then the advantage of the foam cushion of the invention will not be realised. That is to say the padding must enable the apex profile to be apparent to a user, when using such a padded cushion. That is to say the back support in accordance with the present invention can be presented within a cushion cover so as to look, for all intents and purposes, as an ordinary cushion, the benefits being realised when the padding has been compressed.

[0031] While particular embodiments of this invention have been shown in the drawings and described above, it will be apparent, that many changes may be made in the form, arrangement and positioning of the various elements of the combination. In particular, it is to be noted that the cushion's sectional profile is of importance and the width of the cushion can be of an appropriate width for the chair/seat/sofa with which it is to be associated or used. In consideration thereof, it should be understood that preferred embodiments of this invention disclosed herein are intended to be illustrative only and not intended to limit the scope of the invention.

Claims (12)

1. CLAIMS: 1. A back support cushion comprising first and second generally planar main surfaces and having top, bottom and first and second side surfaces; wherein the first main surface has a profile of one half of a teardrop (or pear) section, having a curvilinear apex defined by the teardrop section positioned between 50 and 90mm from the bottom surface of the cushion, wherein the cushion comprises first and second regions, wherein the material of the first region or teardrop section being a conformable material having an hardness value in the range of 175 -265Ibs and the material of the second region providing lateral rigidity to the cushion and having an hardness value in the range of 175 -265Ibs and density of 35 -120Kgm-3.
2. 2. A back support cushion according to claim 1, wherein the first and second sections are made from separate types of foam, which foams are fastened to each other about a common interface.
3. 3. A back support cushion according to claim 2, wherein the first foam has a density in the range of 32 -34Kgm-3.
4. 4. A back support cushion according to claim 2 or 3, wherein the two sections are fastened to each other by one of an adhesive or solvent.
5. 5. A back support cushion according to claim 1, wherein the two regions are defined by a single type of foam, with the second region having an insert to provide lateral stability.
6. 6. A back support cushion according to claim 5, wherein the second region has lateral channels defined therein whereby to enable inserts placed therein wherein the inserts are one of rigid plastics, wooden or metallic members.
7. 7. A back support cushion according to any one of claim 1 -6, wherein the material of the first region comprises polyurethane foam.
8. 8. A back support cushion according to any one of claim 1 -6, wherein the material of the first region comprises memory foam.
9. 9. A back support cushion according to any one of claim 1 -8, wherein the cushion is provided with a cover, the curvilinear apex of the cushion being formed such that the distance of the curvilinear apex is between 50 and 90mm from the base of the cushion with cover.
10. 10. A back support cushion according to any one of claim 1 -8, wherein the cushion is incorporated into a pre-existing cushion associated with an item of furniture, the item of furniture having a seat squab and a back rest, wherein the back support cushion is placed within or in front of the back rest of the item of furniture, wherein the curvilinear apex of the cushion being positioned such that the curvilinear apex is between 50 and 90mm from the base of the seat.
11. 11. A back support cushion according to any one of claim 1 -7, wherein the cushion is provided with a cover, wherein the cushion cover is provided with easily compressed filling of a thickness in the range of 1cm to 15cm whereby the back support cushion can be inserted into a preexisting cover, yet be conformable so that the benefits of the cushion are real ized.
12. 12. A back support cushion substantially as described herein with reference to any one or more of the accompany Figures as shown in the drawing sheets.