Abstract:
In some embodiments, a pillow including a viscoelastic sleeve defining a cavity and filler material positioned within the cavity is disclosed. In other embodiments the pillow includes a sleeve in which is received viscoelastic filler material, or includes a viscoelastic sleeve in which is received other type(s) of filler material.

Description:
RELATED APPLICATIONS 
   Priority is hereby claimed to U.S. patent application Ser. No. 10/489,233 filed on Mar. 10, 2004 (issued on May 30, 2006 as U.S. Pat. No. 7,051,389) and to U.S. Provisional Patent Application Ser. No. 60/383,169 filed on May 24, 2002, the entire contents of which are incorporated herein by reference. 

   FIELD OF THE INVENTION 
   This invention relates generally to pillows or cushions, and more particularly to a pillow or cushion for therapeutic use. 
   BACKGROUND OF THE INVENTION 
   The neck of a person lying in a supine or sidelying position is often out of alignment with the person&#39;s spine. This is commonly the case when the person&#39;s neck is supported by a pillow or multiple pillows such that the neck lies at an angle defined by the deflected height of the pillow(s), and this angle is typically not co-planar with the spine. The deflected height of the pillow is closely related to its stiffness, which is conventionally provided by filling material disposed within a fabric covering. Conventional filling material can include feathers, cotton, or a synthetic filler. 
   SUMMARY OF THE INVENTION 
   To provide a pillow structure more likely to properly align the user&#39;s neck and spine, the invention provides a pillow having multiple foam components. 
   One embodiment of the present invention includes a pillow having a viscoelastic sleeve defining a cavity and filler material positioned within the cavity. 
   Another embodiment of the present invention includes a pillow having outer layers and a filler material comprised of granulated viscoelastic foam disposed between the outer layers. 
   Yet another embodiment of the present invention includes a pillow having outer layers of reinforcing fabric, intermediate layers of viscoelastic foam, and a filler material comprised of granulated viscoelastic foam disposed between the intermediate layers. 
   The present invention also includes a method for manufacturing a pillow. The method includes providing a viscoelastic sleeve that defines a cavity, inserting filler material within the cavity, and closing the sleeve to maintain the filler material within the cavity. 
   The viscoelastic foam responds to changes in temperature such that body heat molds the pillow to conform to the curves of a body for comfort and support. This allows the shape of the pillow to more closely follow the contours of the body and to promote an improved alignment of the neck and spine when a person is in a supine or sidelying position. 
   A cover preferably encases the pillow and contours to the shape of the pillow. The cover is removable, washable, and has a resealable slot through which the pillow may be inserted or removed. The slot extends across an edge portion of the pillow and is preferably opened and closed by a zipper. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view illustrating a pillow embodying the present invention. 
       FIG. 2  is an exploded view of the pillow shown in  FIG. 1 . 
       FIG. 3  is a partial cross-sectional view of the pillow shown in  FIG. 1 . 
   

   Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1-3  illustrate a pillow  10  of the present invention having a sleeve construction formed of multiple layers. The pillow  10  comprises a filler material  14  disposed between layers of viscoelastic foam  18 . The viscoelastic foam layers  18  possess specific thermally responsive properties which cause the pillow  10  to conform to the shape of the portion of a person&#39;s body that contacts the pillow  10 . The viscoelastic foam layers  18  have a lower stiffness or hardness at an elevated temperature as compared to the stiffness at a cooler temperature. Conversely, conventional pillow filler materials typically have a constant stiffness with respect to a changing temperature. The body heat of the person acts to soften the portion of the pillow  10  in contact with the body, while the portion of the pillow  10  not contacting the body remains more firm. As a result, the pillow  10  embodying the present invention allows for greater comfort over a conventional pillow by accommodating each user&#39;s body form. 
   In one embodiment of the present invention, the filler material  14  is granulated, or shredded, viscoelastic foam having a density of about 85 kg/m 3 . However, a suitable density for the viscoelastic foam filler material  14  for an average weight pillow  10 , for example, can be between about 30 and about 140 kg/m 3 . Further, a suitable density for the viscoelastic foam filler material  14  for a light-weight pillow  10 , for example, can be less than about 40 kg/m 3 . Likewise, a suitable density for the viscoelastic foam filler material  14  for a heavy-weight pillow  10 , for example, can be great granulated viscoelastic foam utilized as the filler material  14  can have any density in accordance with the desired characteristics of the pillow  10 . In addition, a suitable viscoelastic foam filler material  14  possesses an indentation load deflection, or “ILD,” of 65% between 100-500 N loading, and a maximum 10% rebound according to the test procedure governed by the ASTM-D-1564 standard. 
   The granulated filler material  14  can be made up of recycled, virgin, or scrap viscoelastic material. The granulated filler material  14  may consist of pieces of a nominal length, or the granulated filler material  14  may consist of pieces of varying lengths. For example, granulated filler material  14  may have a nominal length of about 1.3 cm. Also, granulated filler material  14  may consist of varying lengths between about 0.6 cm and about 2 cm. The granulated filler material  14  can be as short as 0.3 cm and as long as 4 cm, or the filler material  14  can be any length in accordance with the desired characteristics of the pillow  10 . In one preferred embodiment of the invention, the granulated filler material  14  is comprised of 16-20% having a length longer than 2 cm, 38-42% having a length between 1 and 2 cm, and 38-42% of the pieces shorter than 1 cm. Significant cost savings and waste reduction can be realized by using scrap or recycled filler material  14  rather than virgin filler material  14 . The viscoelastic foam used as the filler material  14  is made from a polyurethane foam material, however, the filler material  14  can be made from any other viscoelastic polymer material that exhibits similar thermally-responsive properties. 
   The composition of the filler material  14  can be varied to alter the characteristics of the pillow  10  and the cost of the pillow  10 . In another embodiment of the present invention, the filler material  14  is a combination of granulated viscoelastic foam and a fiber material. The fiber material can be made from any kind of textile, such as an organic textile (cotton) or a synthetic textile, which is often less expensive than viscoelastic foam. In one embodiment of the present invention, the fiber material has a density of about 1 g/cm 3 . However, a suitable density for the fiber material for an average weight pillow  10 , for example, is 0.1-2 g/cm 3 . Further, a suitable density for the fiber material for a light-weight pillow  10 , for example, can be less than about 0.3 g/cm 3 . Likewise, a suitable density for the fiber material for a heavy-weight pillow  10 , for example, can be greater than about 1.8 g/cm 3 . Alternatively, the fiber material utilized in combination with the granulated viscoelastic foam as the filler material  14  can have any density in accordance with the desired characteristics of the pillow  10 . 
   In one preferred embodiment of the invention, the filler material  14  is comprised of about 50% fiber material, while the remaining composition includes the granulated viscoelastic foam. However, a suitable range of fiber material in the filler material  14  for an average-cost pillow  10 , for example, can be between about 20% and about 80%. Further, a suitable range of fiber material in the filler material  14  for a more expensive pillow  10 , for example, can be more than about 30% of the filler material  14 . Likewise, a suitable range of fiber material in the filler material  14  for a less expensive pillow  10 , for example, can be greater than about 70% of the filler material  14 . 
   In yet another embodiment of the present invention, the filler material  14  is a combination of granulated viscoelastic foam and polystyrene balls, which are often less expensive than viscoelastic foam. The filler material  14  of this embodiment can also include an organic or synthetic fiber material depending on the desired characteristics of the pillow  10 . The polystyrene balls may consist of balls of a nominal diameter, or the polystyrene balls may consist of balls of varying diameters. For example, the polystyrene balls may have a nominal diameter of about 5 mm. Also, the polystyrene balls may consist of varying diameters between about 1 mm and about 10 mm. The polystyrene balls can also be as small as 0.5 mm and as long as 20 mm, or the polystyrene balls can be any length in accordance with the desired characteristics of the pillow  10 . 
   In one preferred embodiment of the invention, the filler material  14  is comprised of about 50% polystyrene balls, while the remaining composition includes the granulated viscoelastic foam. However, a suitable range of polystyrene balls in the filler material  14  for an average-cost pillow  10 , for example, can be between about 20% and about 80%. Further, a suitable range of polystyrene balls in the filler material  14  for a more expensive pillow  10 , for example, can be less than about 30% of the filler material  14 . Likewise, a suitable range of polystyrene balls in the filler material  14  for a less expensive pillow  10 , for example, can be greater than about 70% of the filler material  14 . 
   In another embodiment of the present invention, the filler material  14  can also include granulated highly-elastic (“HE”) foam in addition to the granulated viscoelastic foam. HE foam is often less expensive than viscoelastic foam, thus yielding a potentially less expensive pillow  10 . The filler material can be comprised of any single filler described above or any combination of the fillers. Alternatively, the filler material  14  can also include any conventional materials, such as feathers, granulated cotton, cotton fibers, etc. In one embodiment of the present invention, the filler material  14  includes HE foam having a density of about 35 kg/m 3 . However, a suitable density for the HE foam for an average weight pillow  10 , for example, can be between about 20 and about 50 kg/m 3 . Further, a suitable density for the HE foam for a lightweight pillow  10 , for example, can be less than about 25 kg/m 3 . Likewise, a suitable density for the HE foam for a heavyweight pillow  10 , for example, can be greater than about 45 kg/m 3 . Alternatively, the HE foam utilized in the filler material  14  can have any density in accordance with the desired characteristics of the pillow  10 . 
   The granulated HE foam may consist of pieces of a nominal length, or the granulated HE foam may consist of pieces of varying lengths. For example, the granulated HE foam may have a nominal length of about 1.3 cm. Also, the granulated HE foam may consist of varying lengths between about 0.6 cm and about 2 cm. The granulated HE foam can be as short as 0.3 cm and as long as 4 cm, or the granulated HE foam can be any length in accordance with the desired characteristics of the pillow  10 . In one preferred embodiment of the invention, the granulated HE foam is comprised of 16-20% having a length longer than 2 cm, 38-42% having a length between 1 and 2 cm, and 38-42% of the pieces shorter than 1 cm. 
   In one preferred embodiment of the invention, the filler material  14  is comprised of about 50% granulated HE foam, while the remaining composition includes the granulated viscoelastic foam. However, a suitable range of HE foam in the filler material  14  for an average cost pillow  10 , for example, is 20%-80%. Further, a suitable range of granulated HE foam in the filler material  14  for a more expensive pillow  10 , for example, can be less than about 30% of the filler material  14 . Likewise, a suitable range of granulated HE foam in the filler material  14  for a less expensive pillow  10 , for example, can be greater than about 70% of the filler material  14 . 
   As previously mentioned, the filler material  14  is disposed between layers of viscoelastic foam  18 . In one embodiment of the present invention, the layers of viscoelastic foam  18  have a density of about 85 kg/m 3 . However, a suitable density for the layers of viscoelastic foam  18  for an average weight pillow  10 , for example, can be between about 30 and about 140 kg/m 3 . Further, a suitable density for the layers of viscoelastic foam  18  for a lightweight pillow  10 , for example, can be less than about 40 kg/m 3 . Likewise, a suitable density for the layers of viscoelastic foam  18  for a heavyweight pillow  10 , for example, can be greater than about 130 kg/m 3 . Alternatively, the layers of viscoelastic foam  18  can have any density in accordance with the desired characteristics of the pillow  10 . 
   The layers of viscoelastic foam  18  are preferably about 10 mm thick and have thermally-responsive properties similar to the granulated viscoelastic foam of the filler material  14 . Likewise, a suitable thickness for the layers of viscoelastic foam  18  for an average weight pillow  10 , for example, can be between about 5 mm and 15 mm. However, a suitable thickness for the layers of viscoelastic foam  18  for a lightweight pillow  10 , for example, can be less than about 7 mm. Further, a suitable thickness for the layers of viscoelastic foam  18  for a heavyweight pillow  10 , for example, can be greater than about 13 mm. The layers of viscoelastic foam  18  are made from a polyurethane foam material, however, the layers of viscoelastic foam  18  can be made from any other viscoelastic polymer material that exhibits similar thermally-responsive properties. 
   The overall stiffness or hardness of the pillow  10  is dependent on the stiffness of the individual viscoelastic foam layers  18  and the filler material  14 . As such, the overall stiffness or hardness of the pillow  10  may be affected by varying the stiffness of the individual viscoelastic foam layers  18  and/or the filler material  14 . 
   As shown in  FIGS. 1-3 , reinforcing fabric layers  22  are positioned on the outside of the layers of viscoelastic foam  18 . The reinforcing fabric  22  acts as an anchor for stitches  26  that secure together the layers of reinforcing fabric  22  and the layers of viscoelastic foam  18 . Without the reinforcing fabric layers  22 , the viscoelastic foam layers  18 , which are less durable than the layers of reinforcing fabric  22 , would have to directly anchor the stitches  26  such that the filler material  14  is secured between the viscoelastic foam layers  18 . In a pillow having this construction (not shown), the viscoelastic foam layers  18  would likely tear near the stitches  26  as a result of normal use of the pillow. Further, if the viscoelastic foam layers  18  were to tear, then the filler material  14  would spill out. Therefore, the reinforcing fabric layers  22  provide a measure of durability to the pillow  10 . The reinforcing fabric  22  is preferably made from a durable material, such as a cotton/polyester blend. 
   A cover  30  surrounds and encases the pillow  10 , and conforms to the shape of the pillow  10 . The cover  30  is preferably made from a durable and washable fabric material, such as a cotton/polyester blend. As shown in  FIG. 1 , a slot  34  extends across the cover  30  along the cover&#39;s edge. The pillow  10  may be inserted into the cover  30  through the slot  34 . The pillow  10  may also be removed from the cover  30  through the slot  34  to facilitate cleaning of the cover  30 . The slot  34  is resealable to close the cover  30  around the pillow  10  and to open the cover  30  for removing the pillow  10 . A closure device is used to open and close the slot  34 . In the preferred embodiment, the closure device is a zipper  38 , although the closure device could also comprise snaps, buttons, hook and loop fasteners, overlapping flaps, laces, or other similar fasteners. 
   During manufacture, the layers of viscoelastic foam  18  are sewn together with the layers of reinforcing fabric  22  to form a sleeve or casing having an open end, wherein the layers of viscoelastic foam  18  comprise the inner layers of the casing and the layers of reinforcing fabric  22  comprise the outer layers of the casing. The filler material  14  is then inserted through the open end of the casing until the desired amount of filler material  14  is reached within the casing. The open end is then sewn closed, thereby encasing the filler material  14  within the casing and defining a pillow  10 . The pillow  10  is then inserted within the cover  30  and the cover  30  is closed by the zipper  38 .