FIELD OF THE INVENTION: The present invention is related to bed pillows and in particular to bed pillows having a water- bag at the base thereof with a compressible fill material thereabove. Bed pillows are most commonly used for sleeping and are also referred to as headrest pillows.

BACKGROUND OF THE INVENTION:

Waterbase based bed pillows are well known with a preferred structure shown in US Patent 4,847,931. A water-bag support is provided at the base of the pillow essentially extending across the bottom surface. Compressible fill material is provided above the water-bag support. A number of different fill materials can be used, including fiberfill material or traditional down fill. With these loose fill type materials the displacement and movement characteristics of the water-bag support when a user places their head on the pillow are partially dampened by the fill material but the water bag support of the pillow remains quite responsive and is transmitted through the loose fill material. The fiberfill and down filled compressible material above the water-bag resiliently yield and there is a desirable balance between the compressibility of fill material and the water-bag support characteristics that are transmitted through the compressible material.

Prior attempts to use a foam block type compressible fill material above the water-bag have not been effective as the displacement and movement of the water-bag support is largely dampened by the block of foam material that tends to distribute the forces over a larger area.

In addition to the compressibility of the fill material, there is a preferred height of the pillow that is appropriate for most people. This height requires a certain amount of fill material above the water-bag support for a desired cervical elevation that negatively affects the desirable beneficial characteristics of the waterbase support. SUMMARY OF THE INVENTION: A bed pillow according to the present invention comprises a lower water-bag support with a compressible foam layer supported thereabove. The compressible foam layer includes a lower convoluted foam section providing a series of air passages extending across and located between an upper surface of the water-bag support. A block portion of low-density foam is provided above the convoluted foam. The compressible foam layer has a series of air vent channels extending through the compressible foam layer with the channels distributed throughout at least a central portion of the bed pillow.

According to a preferred aspect of the invention, a layer of high density memory foam is provided above the block portion of low-density foam.

According to an aspect of the invention, the series of air vent channels are generally vertically extending ports through the compressible layer.

According to a further aspect of the invention, each air vent channel terminates at an air vent port, and each air vent port is of a cross-sectional area greater than 4.0 mm in diameter.

BRIEF DESCRIPTION OF THE DRAWINGS:

Preferred embodiments of the invention are shown in the drawings wherein:

Figure 1 is a partial perspective sectional view showing the layers of the bed pillow;

Figure 2 is a partial sectional view through the compressible foam layer showing the water-bag support;

Figure 3 is a partial sectional view showing additional details of the series of air vent channels;

Figure 4 is a sectional view through the bed pillow; and Figure 5 is a sectional view similar to Figure 4 supporting the head of a user.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS: The bed pillow 2 as shown in the Figures comprises a water-bag support 4 with a thermal barrier layer 6 provided above and below the water-bag support. A composite foam layer 8 is provided above the thermal barrier and includes a low density polyurethane foam portion 10 having a convoluted lower surface 12 typically of a depth of 3.0 to 4.0 cm. The convoluted lower surface 12 includes extensions 15 with air passages 17 therebetween. A block portion 14 of the low-density polyurethane foam is provided above the convoluted lower portion 12. This block portion is preferably approximately 3.0 to 4.0 cm in thickness. Preferably a layer of memory foam 16 is provided above the block portion 14. The memory foam is preferably approximately 2.0 to 3.0 cm in thickness. With this arrangement the composite foam layer 8 is preferably of a height in the general range of 8.0 to 12.0 cm. A similar height of the composite foam layer is also used if the memory foam is not present.

The layer of memory foam 16 is a denser material and has different characteristics with respect to compression response and subsequent recovery after removal of compressive forces. It is preferred that this layer of memory foam includes small cooling gel particles 34 that are typically distributed throughout the memory foam and provide a cooling effect. Memory foam without distributed cooling gel beads tends to retain heat and this is not particularly helpful with respect to a bed pillow. Preferably cooling gel is also integrated into the v co elastic polyurethane of the memory foam when manufactured to promote cooling while providing the desired resiliency.

The composite foam layer 8 has a series of air vent channels 20. These air vent channels are preferably distributed throughout the composite foam layer but can be limited to distribution throughout a central region of the compressible foam layer 8. This central region is where a person would typically place his or her head. The composite foam layer in some applications may not require such air vent channels. The bed pillow 2 includes an outer cloth ticking 60.

As shown in Figure 2, the series of air vent channels 20 extend vertically and terminate at ports 22. The composite foam layer 8 with these air vent channels has a number of distinct advantages with respect to the pillow. The air vent channels remove a portion of the memory foam layer as well as a portion of the low density polyurethane foam. With this arrangement the weight of the pillow is slightly reduced, however the compression characteristics of the composite foam layer 8 are also significantly altered. With the air vent channels, more localised compression of the composite foam layer 8 occurs as the forces are less distributed throughout the composite foam layer. In this way more localized compression occurs and the movement due to displaced water is more readily transmitted to the surface of the pillow and the user.

The polyurethane foam layer alone or the composite foam having a polyurethane foam lower portion with an upper layer of polyurethane memory foam, has been used in conventional non waterbase bed pillows and is preferred by some users. However the use of these foams in a bed pillow having a waterbase lower support layer has problems as the desirable responsive characteristics of the waterbase support is overdampened by the polyurethane foam.

As will be further described, the inventors have adapted the compressible foam component to function effectively with the waterbase support. This adaption can work effectively with or without a memory foam upper layer. The use of memory foam is desirable and a preferred commercial embodiment has a polyurethane base and memory foam upper layer supported by a waterbase. As shown in Figure 5 when a person places their head on the pillow, the weight of the head 30 compresses the composite foam directly below the head and in particular compresses the convoluted lower portion 12 of the pillow as the compressive strength of the extending portions of the convoluted foam is low. The block portion 14 of the low-density polyurethane foam also compresses significantly in the area immediately below the person's head. The memory foam compresses in this area but the memory foam is denser and has different desirable compression characteristics. The water in the water-bag 4 will also be partially displaced outwardly as generally shown by the arrows 42. The compression of the foam is quite localized with portions either side of the head undergoing significantly less compression and providing some support. With this arrangement there is considerable compression of the convoluted lower portion 12 of the composite foam layer 8 as well as localized compression of the block portion 14 in the area immediately below the person's head 30. The convoluted lower portion 12 either side of the person's head undergoes some compression but the amount of compression continues to decrease as distance away from the person's head increases. Air is free to pass generally through the convoluted area above the surface of the airbag and air can also pass through the series of air vent channels that extend through the composite foam layer. The venting air passage outwardly is schematically shown by arrows 45. As shown in the drawings there has also been some compression of the air vent channels immediately below the persons head. The compression of the foam will displace air through the vent channels that is dissipated or vented through the convoluted lower portion 12. Movement of a person's head will force air out in any air channels that are compressed and air will flow into any air channels that expand. This provides a cooling air exchange or pumping of air into or out of the air vent channels during use of the pillow.

The convoluted foam includes a series of offset rows where adjacent extensions of each row are approximately 5 cm apart and aligned adjacent extensions of every other row are approximately 5 cm apart. These aligned extensions of every other row are aligned in a column type pattern. The extensions of adjacent rows are offset at a 45 degree angle. Preferably, the composite foam is made by cutting a block of foam with memory foam either side thereof to form two pieces of composite foam for a bed pillow. Preferably the composite foam layers are drilled to provide the vertical air channels. The extensions 15 can be grouped in fours with a large recess 19 located centrally therebetween. This recess 19 is the cut section to form an extension in the other portion of the block of foam. These recesses 19 are also positioned in a grid pattern.

The spacing between immediately adjacent extensions 1 is in the range of 1.5 to 4.0 cm.

Preferably the compressible foam layer is 8 to 10 cm thick. Preferably the memory foam is 1.5 to 3.0 cm thick.

It has been found that the arrangement of the convoluted lower portion 12 with the series of air vent channels 20 in combination with memory foam 16 provides a desirable support above the water-bag. The composite foam layer with the series of air vent channels provides appropriate localized compression and displacement of water when a person places their head on the pillow. The natural tendency of the memory foam and the low-density polyurethane foam to retain heat has been reduced by promoting air circulation through the pillow. Importantly, the compressible foam layer now provides significant localized compression when a person places their head on the pillow and the localized compression provides the desirable displacement of the water in the water-bag support. This water displacement has been previously found to be helpful in alleviating issues associated with neck pain and headaches.

With the modified structure of the pillow it is possible to provide effective transmission of the displacement characteristics of the water-bag support through the composite foam layer while also providing the desirable features of memory foam at an upper surface of the pillow. By providing cooling gel as small beads in the thermal gel or directly adding cooling gel into the composition of the memory foam, the tendency of the memory foam to retain heat is offset or significantly reduced. The air vent channels and the resulting air exchange are also of assistance in heat removal from the memory foam, and/or from the polyurethane layer.

The series of air vent channels allows modification of the compression characteristics of foam layer while still providing a desired height of low-density polyurethane foam and memory foam combination. Our earlier pillow with loose fiberfill provided above the water-bag 4 provides a desirable combination of flexibility, compression and appropriate displacement of water either side of the persons head that is difficult to achieve with a composite foam layer.

A one piece polyurethane foam layer without the features of the convoluted surface and the series of air vent channels distributes the forces and the desirable responsive characteristics of the water-bag support are dissipated. Furthermore the nature of polyurethane foam to retain heat is not desirable, and the series of ventilating channels extending through the foam block connected to the lower convoluted surface is effective in providing ventilation and reduces heat retention.

The size, shape and the number of channels can vary however it is desirable that the series of channels are provided in at least a central portion of the pillow. A strip type solid area can be provided either end of the pillow as this portion is not typically in use. Having some additional firmness either end of the pillow can also provide feedback to the user to return towards a central portion. The memory foam with a height of approximately 2.5 cm provides a desirable softness and the convoluted lower portion is preferably about 3.25 cm and quickly yields when compressed. The solid portion of the polyurethane foam provided above the convoluted over surface is preferably 3.25 cm.

The size of the air vent channels can also vary however the air vent channels have a port opening size at least equal to a diameter of 4 mm is preferred. If the size of the air vent channels is reduced more air vent channels can be provided. In a preferred embodiment about 20% of the upper surface area of the pillow is provided with air vent channels. The particular size of the convoluted lower portion is chosen to provide compressive characteristics of the pillow to initially yield a desired amount. The air vent channels in addition to affecting the compressive strength and weight of the pillow, provide cooling and allow the responsiveness of the water-bag support to be transmitted to the user.

Providing the memory foam and the low density polyurethane foam as a composite block maintains the fill material in the predetermined order and also maintains the air channels connected through the materials to keep the passages clear and functioning. This structure also simplifies assembly of the pillows.

With waterbase pillows, the user fills and adjust the amount of water to provide a desired firmness. For example in Applicant's commercial pillow 60-80 ounces of water provides a soft firmness, 80 to 100 ounces is a medium firmness and 100 to 130 ounces is firm. It is also recommended to remove air from the waterbag support to prevent or reduce noise caused by sloshing.

Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from the invention defined by the appended claims.