Patent Publication Number: US-6986691-B2

Title: Foam stabilization for personal flotation device

Description:
FIELD OF THE INVENTION 
   This invention relates generally to personal flotation devices and, more specifically, to foam stabilization for personal flotation devices. 
   BACKGROUND OF THE INVENTION 
   Approved United States Coast Guard personal flotation devices are required for many water activities. Personal flotation devices come in many shapes, colors and materials, but typically incorporate buoyant foam material. A popular type of personal flotation device is designed as a vest that fits around the user&#39;s neck and upper torso, commonly secured to the user via a zipper, adjustable straps or belts. 
   Swimwear-style personal flotation devices have been developed, particularly for use with children. These devices incorporate buoyant foam material into a garment designed for continuous wear, similar to a swimming suit. As with most personal flotation devices, maintaining the location of the buoyant foam material with respect to the user&#39;s head and torso is critical to ensure proper flotation. Incorporating buoyant foam material into swimwear-style personal flotation devices has presented unique challenges. Should the buoyant foam material shift from its prescribed location in the chest and upper back areas, or curl or fan excessively, the attitude of the user in the water can be adversely influenced and the personal flotation device not perform the functions for which it is intended. 
   Solid foam blocks have been used in swimwear-style personal flotation devices in an effort to achieve proper flotation. The solid foam blocks, for example made from PVC foam, have been sewn into various portions of the swimsuit in an effort to maintain buoyancy and balance when worn by a user in the water. Using solid PVC blocks reduce the likelihood that the buoyant foam material will curl or fan. However, solid foam blocks are bulky, add significant weight and cost to the product and are cosmetically unappealing. 
   Flexible buoyant foam material, for example multiple layers of the polyethylene foam more commonly found in traditional life jackets and vests, is a more promising alternative. Use of multiple flexible layers of buoyant material avoids much of the bulk and weight associated with solid foam blocks. The stretchy nature of the fabrics used as a shell and lining for swimwear-style personal flotation devices presents new challenges when multiple layers of buoyant material are used. While such layers maintain an ideal position in flotation garments made from limited stretch material such as woven fabrics or marine netting, when used in the stretchy swimwear-style fabrics (for example neoprene or knit fabrics), the layers tend to shift from the prescribed location or curl or fan excessively. This results in an undesirable change in the attitude of the user in the water and threatens the proper performance of the personal flotation device. 
   Prior attempts to solve problems associated with using multiple layers of polyethylene foam with swimwear-style personal flotation devices have been largely unsuccessful. Bonding the polyethylene foam layers together to form a single layer reduces the curling and fanning issues while avoiding the weight issues present when using solid blocks of foam. But this solution requires the addition of an adhesive application step, which in turn introduces significant complexities in the manufacture of the personal flotation device. It also raises questions about the durability of the bond over time and use. Finally, use of an adhesive introduces safety concerns about the proper ventilation for the adhesive, both during manufacture and subsequent storage by the seller and end user, as well as long term potential health effects on the user. 
   Sewing pieces of the swimwear-style fabric directly to the flexible foam material to serve as attachment points to secure the foam into the garment is likewise not feasible. Such stitching is not an option when using preferred polyethylene foam material in the thickness required in swimwear-style personal flotation devices. 
   Thus, there is a need for improved stabilization of multiple layers of flexible foam material when used in personal flotation devices to reduce curling and fanning issues and avoid bulk and weight while providing a cosmetically appealing flotation device. 
   SUMMARY OF THE INVENTION 
   The preferred embodiment of the present invention is directed to a personal flotation device including a cover forming one or more compartments incorporating flotation material consisting of multiple layers of flexible buoyant material adjacent to each other within the covered compartment. One or more apertures are made in the layers of buoyant material. A fabric band or belt is passed through each aperture in the layers of buoyant material, the ends of the layers preferably connected. The fabric band limits the movement of each layer of buoyant material relative to the other layers of buoyant material. 
   In an alternative embodiment, the fabric band is connected to the cover of the personal flotation device to limit the movement of each layer of buoyant material within the compartment. 
   In yet an alternative embodiment, the flotation stabilization system and method of the present invention is incorporated into a swimwear-style personal flotation device incorporating buoyant material into a garment designed for continuous wear, similar to a swimming suit. 
   Accordingly, the present invention provides for improved stabilization of multiple layers of flexible foam material when used in personal flotation devices to reduce curling and fanning and avoid bulk and weight while providing a cosmetically appealing flotation device. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings. 
       FIG. 1  is a front view of a swimwear-style personal flotation device for use in a preferred embodiment of the present invention; 
       FIG. 2  is a back view of the preferred swimwear-style personal flotation device of  FIG. 1 ; 
       FIG. 3  is an illustration of layers of flexible buoyant foam material for use in a swimwear-style personal flotation device in accordance with a preferred embodiment of the present invention; 
       FIG. 4  is the side view of the layers of flexible buoyant foam material illustrated in  FIG. 2 ; 
       FIG. 5  is an illustration of layers of flexible buoyant foam material for use in a swimwear-style personal flotation device in accordance with an alternative embodiment of the present invention; 
       FIG. 6  is a cutaway front view of the swimwear-style personal flotation device shown in  FIG. 1  illustrating the layers of flexible buoyant foam material used in a swimwear-style personal flotation device in accordance with a preferred embodiment of the present invention; and 
       FIG. 7  is a cutaway back view of the swimwear-style personal flotation device shown in  FIG. 2  illustrating the layers of flexible buoyant foam material used in a swimwear-style personal flotation device in accordance with a preferred embodiment of the present invention. 
   

   DESCRIPTION OF THE PRESENT INVENTION 
   The preferred embodiment of the present invention is directed to improved stabilization of multiple layers of flexible foam material in personal flotation devices. While the present invention has particular application when used in swimwear-style personal flotation devices, commonly referred to as personal flotation vests, it has general application to various types of personal flotation devices. 
   With reference to  FIGS. 1 and 2 , the preferred swimwear-style personal flotation vest  10  includes a front right segment  20  incorporating a buoyant material (not shown), a front left segment  22  incorporating a buoyant material (not shown), a back right segment  24  incorporating a buoyant material (not shown), a back left segment  26  incorporating a buoyant material (not shown), a front swimsuit segment  28  and a back swimsuit segment  30 . In the preferred embodiment, each segment is comprised of a flexible neoprene or stretchable fabric (for example knit fabric). 
   The front right segment  20 , the front left segment  22 , the back right segment  24  and the back left segment  26  are preferably connected together to form a vest shape. The right front segment  20  is connected to the back right segment  24  over the user&#39;s right shoulder (not shown) along seam line  40  and below a right arm opening  90  on the right side of the vest along seam line  42 . The left front segment  22  is connected to the back left segment  26  over the user&#39;s left shoulder (not shown) along seam line  44  and below a left arm opening  92  on the left side of the vest along seam line  46 . The front right segment  20  and the front left segment  22  are preferably connected along seam line  50 . The back right segment  24  is preferably connected to the back left segment  26  via zipper  100 . The connections between the front right segment  20 , the front left segment  22 , the back right segment  24  and the back left segment  26  form a neck opening  94  in the vest  10 . 
   The front right segment  20  and the front left segment  22 , joined along seam line  50 , are connected to front swimsuit segment  28  along seam line  52 . The back right segment  24  and the back left segment  26 , joined via zipper  100 , are connected to the back swimsuit segment  30  along seam line  56 . The front swimsuit segment  28  is connected to the back right segment  24  and the back swimsuit segment  30  across the user&#39;s right hip (not shown) along seam  60 . The front swimsuit segment  28  is connected to the back left segment  26  and the back swimsuit segment  30  across the user&#39;s left hip (not shown) along seam  62 . The front swimsuit segment  28  and the back swimsuit segment  30  are connected along seam line  64  to form a right leg opening  96  and a left leg opening  98 . 
   In the preferred embodiment, the front right segment  20 , the front left segment  22 , the back right segment  24  and the back left segment  26  each have exterior fabric shells  20   a ,  22   a ,  24   a  and  26   a  and corresponding interior fabric liners  20   b ,  22   b ,  24   b  and  26   b  (not shown). The exterior fabric shell  20   a  is preferably connected to the interior fabric liner  20   b  along seam lines  40 ,  42 ,  50  and  52  and along the front sleeve  68  of the right arm opening  90  and the front collar  70  of the neck opening  94 . The exterior fabric shell  22   a  is preferably connected to the interior fabric liner  22   b  along seam lines  44 ,  46 ,  50  and  52  and along the front sleeve  72  of the left arm opening  92  and the front collar  74  of the neck opening  94 . The exterior fabric shell  24   a  is preferably connected to interior fabric liner  24   b  along seam lines  40 ,  42  and  56 , via zipper  100 , and along the back sleeve  76  of the right arm opening  90  and the back collar  80  of the neck opening  94 . The exterior fabric shell  26   a  is preferably connected to interior fabric liner  26   b  along seam lines  44 ,  46  and  56 , via zipper  100 , and along the back sleeve  78  of the left arm opening  92  and the back collar  80  of the neck opening  94 . Connecting the exterior and interior segments is preferably accomplished by stitching the fabric of the adjoining segments together along the seam lines. The buoyant material incorporated into the front right segment  20 , the front left segment  22 , the back right segment  24  and the back left segment  26  is retained between exterior fabric shells  20   a ,  22   a ,  24   a  and  26   a  and corresponding interior fabric liners  20   b ,  22   b ,  24   b  and  26   b.    
   In a preferred embodiment, the front right segment  20 , the front left segment  22  and the front swimsuit segment  28  are formed of a single piece of fabric and the back right segment  24 , the back left segment  26  and the back swimsuit segment  30  are formed of a separate, single piece of fabric. In this embodiment, the front right segment  20  incorporating a buoyant material (not shown), the front left segment  22  incorporating a buoyant material (not shown) and the front swimsuit segment  28  are connected to the back right segment  24  incorporating a buoyant material (not shown), the back left segment  26  incorporating a buoyant material (not shown) and the back swimsuit segment  30  along seam lines  40 – 46 ,  50 – 52 ,  56 , and  68 – 80  and via zipper  100 . Connecting the segments is preferably accomplished by stitching the fabric of the adjoining segments together along the seam lines. 
   The foam stabilization system and method of the present invention is described more particularly with reference to  FIGS. 3 and 4 . In the preferred embodiment, buoyant material incorporated into the front right segment  20 , the front left segment  22 , the back right segment  24  and the back left segment  26  includes multiple layers of buoyant material secured together to limit movement of the buoyant material within the vest  10 . 
   More specifically, the preferred foam stabilization system  110  of the present invention includes multiple layers  110   a ,  110   b ,  110   c ,  110   d  and  110   e . These layers are preferably made from a flexible buoyant material such as polyethylene foam. Five layers of buoyant material are described. However, the number of layers used may vary according to the operational needs for the particular personal flotation device. For example, smaller children may require less buoyant material in the vest segments than larger children, and therefore fewer layers may be required. Likewise, the number of layers may vary for each segment of the personal flotation device. 
   The foam layers  110   a ,  110   b ,  110   c ,  110   d  and  110   e  are preferably secured to each other by way of a fabric band  112  inserted into one or more slits or other apertures  114  formed through the layers. Once passed through the slits in the foam layers, the ends of the fabric band  112  are preferably sewn together along seam line  116 . The type of fabric band used to secure the foam layers may vary, but is preferably made from United States Coast Guard approved fabric designed to maintain its shape and strength under conditions associated with the use of personal flotation devices. Alternative ways to secure the foam layers to each other include other types of fabric bands, bands made out of different material, such as rope, wire, cable or a variety of synthetic materials. Likewise, while the thread used to secure the ends of the fabric band together may vary, it is preferably United States Coast Guard approved thread designed to maintain its integrity under conditions associated with the use of personal flotation devices. Alternatives ways to secure the ends of the fabric band together include tacking, gluing, heat bonding, radio frequency (RF) welding and Velcro. 
     FIGS. 3 and 4  show the preferred embodiment of the present invention utilizing two slits through the multiple layers of buoyant material. Virtually any number of slits may be used to facilitate securing the multiple layers and achieving the benefits of foam stabilization in the personal flotation device. The number of slits may vary according to the size of the layers of buoyant material. Larger personal flotation devices may require more than two slits to secure the layers of buoyant material. Conversely, only a single slit may be required to secure the layers needed for a small personal flotation device. 
   In a similar fashion, the number of slits may vary according to the shape of layers of buoyant material. The preferred embodiment is directed to a personal flotation device for use in supporting the upper torso of a user. This dictates that the layers of buoyant material be in the shape of a torso. In this embodiment, using two slits to secure the layers of buoyant material improves foam stabilization by limiting the distance the foam layers can shift from their prescribed location and reducing curling or fanning of the material. Alternative embodiments may require a different number of slits. For example, a belt-shaped personal flotation device may require only a single slit to appreciably limit movement of multiple layers of buoyant material. Conversely, a more elaborately shaped vest or swimsuit-style personal flotation device may require more than two slits to appreciably limit movement of the multiple layers of buoyant material. 
   As shown with reference to  FIG. 5 , the size and shape of the multiple layers of buoyant material may be varied without losing the advantages associated with the present invention.  FIG. 5 , for example, shows an alternative foam stabilization system  120  in which the layers of buoyant material ( 120   a ,  120   b ,  120   c ,  120   d  and  120   e ) are of different sizes and shapes to create a beveled edge or the overlay of a larger layer ( 120   e ) to create a rounded edge. Use of these different sizes and shapes would normally subject the layers of buoyant material to increased curling and fanning and a corresponding diminishment in the effectiveness of the personal flotation device. By using the present invention, including the fabric band  122  inserted into one or more slits  124  formed through the layers, the ends of which are preferably secured along seam line  126 , the buoyant material in these types of shapes is not as susceptible to the curling and fanning problems. 
   In an alternative embodiment, as shown with reference to  FIGS. 6 and 7 , the fabric bands  112   a  and  112   b  are used to further secure the multiple layers of buoyant material of the foam stabilization system  110  within the exterior fabric shells  20   a ,  22   a ,  24   a  and  26   a  and the interior fabric liners  20   b ,  22   b ,  24   b  and  26   b . This is preferably accomplished by connecting the fabric bands  112   a  and  112   b  to the exterior fabric shells  20   a ,  22   a ,  24   a  and  26   a  or the interior fabric liners  20   b ,  22   b ,  24   b  and  26   b  along one or more of the seam lines  40 – 46 ,  50 – 52 ,  56  and  68 – 80 . Alternatively, the fabric bands  112   a  and  112   b  may be attached to the shell and liner fabric at a different location and separate from any seam lines, depending on the location of the slit and corresponding fabric band through the layers of buoyant material. 
   In this example, with reference to  FIG. 6 , the layers of buoyant material incorporated into front right segment  20  are connected to the exterior fabric shell  20   a  (not shown) and to the interior fabric liner  20   b  by catching the fabric band  112   a  in the stitching  130  along the seam line  50  and catching the fabric band  112   b  in the stitching  132  along the seam line  52 . The layers of buoyant material incorporated into front left segment  22  are connected to the exterior fabric shell  22   a  (not shown) and to the interior fabric liner  22   b  by catching the fabric band  112   a  in the stitching  130  along the seam line  50  and catching the fabric band  112   b  in the stitching  132  along the seam line  52 . 
   With reference to  FIG. 7 , the layers of buoyant material incorporated into back right segment  24  are connected to the exterior fabric shell  24   a  (not shown) and to the interior fabric liner  24   b  by catching the fabric band  112   a  in the stitching  140  along zipper  100  and catching the fabric band  112   b  in the stitching  144  along the seam line  56 . The layers of buoyant material incorporated into back left segment  26  are connected to the exterior fabric shell  26   a  (not shown) and to the interior fabric liner  26   b  by catching the fabric band  112   a  in the stitching  142  along zipper  100  and catching the fabric band  112   b  in the stitching  144  along the seam line  56 . 
   The present invention offers advantages over personal flotation devices incorporating solid foam materials. By using multiple layers of flexible foam material, such as polyethylene foam, the present invention provides improved stabilization while avoiding inflexible, bulky and heavy vests that are not only cosmetically unappealing but may be too cumbersome to successfully incorporate into swimwear-style personal flotation devices for children. By securing the multiple layers of flexible foam material using the slit locations, the present invention reduces curling and fanning issues that may alter the attitude of the user in the water and threaten the proper performance of the personal flotation device. 
   While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. While specific details of certain embodiments of the invention are set forth in the preceding description and in  FIGS. 1–7  in order to provide a thorough understanding of such embodiments, the present invention may have additional embodiments or be practiced without several of the described details. For example, the personal flotation device may be of various shapes and include a different number of segments. In an alternative embodiment, the personal flotation device  10  may have fewer than four segments connected together to form a vest shape. For example, a single front segment and a single back segment may be connected together to form a vest shape. In yet an alternative embodiment, multiple segments may be connected to form a personal flotation device other than in the shape of a vest. For example, two front segments may be connected around the neck of the user in a horse collar configuration. This alternative embodiment may further include support straps connected to the front segments and encircling the user to maintain the front segments on the user to maximize appropriate flotation. In another alternative embodiment, a single segment, either in the front or the back, may be removably connected via straps to the user to provide appropriate flotation. 
   In yet alternative embodiments, the zipper of the personal flotation device may be located along the front or sides of the vest. Alternatively, no zipper may be used, but rather the segments may be expanded to allow fitting to a user by stretchable fabric, buttons, clasps, Velcro or other similar connection methods. 
   In still alternative embodiments, one or more of the distinct segment may be merged with other segments such that several segments of the vest  10  are formed from unitary fabric material, thus reducing the need to connect separate fabric segments. Likewise, the buoyant material may be incorporated into a single piece of multiple layer fabric material rather than retained by connecting a separate shell and liner. 
   In addition, the precise location of seam lines may vary according to the desired shape and size of the vest  10 . The fabric segments of the vest  10  may be connected together using a variety of methods including sewing, tacking, gluing, heat bonding, RF welding and Velcro. Likewise, in addition to sewing, the fabric band  112  or  122  may be connected to the front right segment  20 , the front left segment  22 , the back right segment  24  and the back left segment  26  by other methods such as tacking, gluing, heat bonding, RF welding and Velcro. 
   Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.