Patent Abstract:
A method is provided for attaching an elongated webbing member to an edge of a pool cover, comprising positioning the edge of the pool cover so that a portion of the pool cover edge is in contact with a portion of the webbing, and heat sealing the webbing portion to the pool cover edge portion. An assembly is provided for coupling a pool cover to a connector mechanism attached to a pool, comprising a pool cover comprising at least one pool cover edge, and a webbing coupled to at least a portion of the pool cover edge by a heat seal between a portion of the webbing and a portion of the pool cover edge. An apparatus is also provided for forming a webbing attached to the edge of a pool cover.

Full Description:
RELATED APPLICATION 
     This application claims the priority of provisional application No. 60/334,094, filed Nov. 29, 2001. 
    
    
     BACKGROUND 
     1. Field 
     The present disclosure relates to swimming pool covers, and, more particularly, to a method and apparatus for attaching webbing to the edges of pool covers. 
     2. Background 
     Swimming pools are commonly covered to prevent debris from entering the pool, to preserve chemical treatments in the water and to heat the pool in the case of a solar cover. Typically, a pool cover will extend over the entire surface of the pool during periods of non-use and then be retracted during periods of use. The cover may be extended and retracted by mechanical or automatic means. In either case, a track assembly is usually connected to or built into the walls for guiding the edges of the cover as it traverses the pool. The pool cover typically has some means connected along the edge of the cover interacting with the track assembly to facilitate movement of the pool cover. 
     The pool cover may be fabricated from a vinyl-coated mesh made up of a dacron thread or “skrim” covered on top and bottom by vinyl coating. The result is a strong, durable and waterproof material that is ideal for long-term, maintenance-free use. The webbing may be made out of canvas or sail cloth, so that it can endure the mechanical stresses and wear placed on it as the bead slides along the tracking assembly and as weight is placed on the cover. 
     The webbing may be connected to the pool cover by thread stitches running along the webbing. Although the stitches are made of strong and durable thread, they are vulnerable to wear and may eventually wear out before the cover or the webbing. This wear occurs as the result of several factors, including ultraviolet rays from sunlight, chemical corrosion from pool chemicals and the mechanical stresses described above. Accordingly, it is not unusual for periodic repairs to be required to the thread stitching in order to maintain the integrity of the connection between the webbing and the pool cover. 
     Accordingly, there is an important need for an improved connection between the pool cover and the webbing that forms the edge bead for the pool cover. An improved webbing material and method of attaching the material to the pool cover is needed to reduce maintenance on the pool cover and to increase safety and durability for the pool cover. 
     SUMMARY 
     The present disclosure provides an improved method for attaching border webbing to an edge of the pool cover to form a bead for guiding the webbing along an encapsulated track. The border webbing is heat sealed to the edge of the pool cover to form a durable attachment thereto. The webbing and the edge of the pool cover are made of heat sensitive material that become plastic and form a bond with the application of heat. 
     One application of the disclosure comprises a method for attaching an elongated webbing member to an edge of a pool cover, wherein the edge of the pool cover is positioned so that a portion of the pool cover edge is in contact with a portion of the webbing. The portion of the pool cover edge is then heat sealed to the portion of the webbing. 
     The method further comprises wrapping the webbing around an elongated filler member, so that at least one flap extends from the filler member, positioning the portion of the pool cover edge to overlap the flap, and applying heat to cause a heat seal between the portion of the pool cover edge and the flap. Preferably, the portion of the pool cover edge and/or the flap are composed of a heat sensitive material that will form the heat seal. 
     Another application comprises a pool cover having at least one pool cover edge, a webbing coupled to at least a portion of the pool cover edge by a heat seal between a portion of the webbing and a portion of the pool cover edge. 
     Additionally, the portion of the webbing and/or the portion of the pool cover edge may be made of a thermoactive material, such as vinyl, that becomes plastic with the application of heat, to form the heat seal. As used herein, the term “thermoactive material” means a material that is sufficiently sensitive to heat to become pliable or plastic in consistency, so as to provide a surface appropriate for heat welding. The webbing may be wrapped around a filler element to form a bead, so that the bead substantially maintains its shape under mechanical stress to guide the edge of the pool cover along a mechanical track. 
     Another implementation includes an apparatus for forming a webbing attached to the edge of a pool cover, comprising a positioning element for disposing a portion of the webbing in contact with a portion of the pool cover edge and a heating element for applying heat to form a heat seal between the webbing portion and the pool cover edge portion. 
     Additional optional features include a pressing element for consolidating the heat seal between the webbing portion and the pool edge cover portion. The positioning element may provide a flap extending from the webbing to overlap the portion of the pool cover edge and form the heat seal therewith. The apparatus may further comprise an element for wrapping the webbing around an elongated filler element, wherein the wrapping element forms the portion of the webbing to include at least one flap extending from the filler element. The portion of the pool cover edge may extend between first and second flaps of the webbing. The heating element may include a first nozzle to apply heat to the first flap and a second nozzle to apply heat to the second flap. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and the disclosure will be better understood by reference to the following description of an example taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a plan view of a pool showing a pool cover guided by a tracking assembly in the pool walls; 
         FIG. 2  is a perspective view of a prior art structure showing a webbing and bead formed along the edge of the pool cover and carried in the tracking assembly; 
         FIG. 3  is a perspective view of a prior art structure including an edge of a pool cover sewn to a webbing and bead for attaching to the tracking assembly of  FIG. 2 ; 
         FIG. 4  is a perspective view of another prior art structure including an edge of a pool cover sewn to webbing and bead for attaching to the tracking assembly of  FIG. 2 ; 
         FIGS. 5A–C  are schematic views showing the steps involved in fabricating a webbing structure; 
         FIG. 6A  is a perspective view showing the webbing structure connected to an edge of the pool cover; 
         FIG. 6B  is a side view of the webbing structure shown in  FIG. 6A ; 
         FIGS. 7A and 7B  are side views of another implementation showing a webbing structure connected to an edge of the pool cover; 
         FIG. 8  is another perspective view showing the webbing structure of  FIG. 6A ; 
         FIG. 9  is a schematic view of an apparatus for forming the webbing structure; 
         FIGS. 10 and 11  are side views of the apparatus of  FIG. 9 ; 
         FIG. 12  is a cross-section partial view of the side views of  FIGS. 10 and 11 ; 
         FIG. 13  is a side view of the apparatus of  FIG. 9  with part of the apparatus rotated; 
         FIG. 14  is a perspective view of the apparatus of  FIG. 9  with part of the apparatus rotated; and 
         FIG. 15  is another perspective view of the apparatus of  FIG. 9  with the apparatus in operation. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one example, in one form, and such exemplification is not to be construed as limiting the scope of the disclosure in any manner. 
     DETAILED DESCRIPTION 
     In  FIG. 1 , a rectangular swimming pool  10  is shown having a pool deck  12  and coping  14  surrounding the pool. An automatic pool cover  16  extends from a pool cover mechanism  18  in a cover assembly box  20  disposed at one end of the pool. A leading edge bar  22  at the front edge of the pool cover  16  rides in a track assembly  24  along the interior walls of the pool. Deck  12  is generally horizontal and is preferably constructed from concrete. Coping  14  connects to deck  12  in a substantially coplanar fashion along the edge of deck  12  facing the interior of swimming pool  10 . Track assembly  24  may be of any suitable structure to retain the edge of the pool cover as it slides in the track. 
       FIG. 2  shows an encapsulation track assembly  30  having an elongated chamber  32  therein. The pool cover  16  is connected along its edge to an elongated bead  36  comprised of a wrapped rope or filler  35  that is captured in chamber  32 . The pool cover  16  extends out through a slot  38  in chamber  32 . Chamber  32  is sufficiently large to allow the bead  36  to slip therethrough as the cover  16  moves. Likewise, slot  38  is ample in width to allow the pool cover edge to move easily along the slot, but is small enough to restrain the bead  36  within chamber  32 . 
     In  FIGS. 3 and 4 , prior art methods are shown, wherein bead  36  is formed by wrapping an elongated webbing member  40  around rope  36  and attaching it to pool cover  16 . The webbing member  40  is wrapped around the rope  36  and then sewn to the edge  31  of the pool cover  16 . 
     In  FIG. 3 , a first fold portion  41  is formed along the edge  31  of the pool cover  16  and then sewn onto the webbing  40 , using a line of thread stitching  42 . A second fold portion  43  is formed over the top of portion  41  and a second line of thread stitching  44  is added to secure the second fold portion  43  to the webbing  40 . This approach requires two sewing passes but protects one of the threads from sunlight. In  FIG. 4 , first and second fold portions  41  and  43  are formed first and then sewn with two stitch lines  45  and  46  providing a double stitching through both folds in one pass, but exposing both lines of stitching to the sunlight. 
     As previously mentioned, the pool cover  16  may be fabricated from a vinyl-coated mesh made up of a dacron thread or “skrim” covered on top and bottom by vinyl coating. The result is a strong, durable and waterproof material that is ideal for long-term, maintenance-free use. The webbing may be made out of canvas or sail cloth, so that it can endure the mechanical stresses and wear placed on it as the bead  36  slides along the encapsulation assembly  30  and as weight is placed on the cover  16 . 
     The thread stitches  45  and  46  or  42  and  44  are vulnerable to extensive wear. Although very strong and durable thread is used and multiple stitch lines are applied, the thread may eventually wear out before the cover or the webbing. This wear occurs as the result of several factors, including ultraviolet rays from sunlight, chemical corrosion from pool chemicals and the mechanical stresses described above. Accordingly, it is not unusual for periodic repairs to be required to the thread stitching in order to maintain the integrity of the connection between the webbing and the pool cover. 
     Looking now at  FIGS. 5A–C , a preferred application of the method of the present disclosure is shown. As shown in  FIG. 5A , in a first step, a pool cover  50  includes a pool cover edge  51  disposed adjacent to an elongated rope or filler member  52 . A webbing member  55  is disposed on the other side of the rope member  52 . Preferably the pool cover  50  is composed of a mesh made up of a dacron thread or “skrim” covered on top and bottom by vinyl coating. The webbing member  55  is composed of an extremely strong and durable fabric mesh having one side  53  coated by vinyl and the other side  56  not coated by vinyl. 
     As shown in  FIG. 5B , in a second step, an appropriate mechanism (not shown) folds webbing member  55  over filler member  52  to form upper and lower flaps  57  and  58  extending above and below pool cover edge  51 . The surfaces  59  and  60  of flaps  57  and  58 , respectively, that are adjacent to pool cover edge  51  are part of the vinyl-coated surface  53  and extend over the vinyl-coated pool cover edge  51 . 
       FIG. 5C  shows a third step, wherein upper and lower flaps  57  and  58  are formed around filler member  52  to form bead  62 . Flaps  57  and  58  are rolled flush with pool cover edge  51 . Heat and pressure are applied to form a heat weld or seal  55  comprised of bonded flaps  57  and  58  bonded on either side of pool cover edge  51 . 
       FIG. 6A  shows a perspective view of the heat sealed webbing  55  and pool cover edge  51  according to the present disclosure. Bead  62  is formed by wrapping webbing  55  around the rope or filler element  52 . Flaps  57  and  58  are heat sealed to the pool cover edge  51  to form a strong, durable heat seal between the flaps  57  and  58  of the webbing  55  and the pool cover  50 . 
       FIG. 6B  shows a side view of the structure shown in  FIG. 6A . Preferably, the bead  62  formed by the elongated filler element  52  and the webbing  55  are impervious to wear along the track assembly  30 , shown in  FIG. 2 , and the filler element  52  is composed of a material that substantially maintains its shape when mechanical stress and tension is applied. Thus, as shown in  FIG. 2 , the bead  36  can slide in chamber  32  along the encapsulated track  30  without risk that the bead will deform and be pulled out of the slot  38  in chamber  32  by transverse forces acting on pool cover  16 . 
       FIG. 7A  shows an alternative implementation of the present disclosure wherein a webbing is attached to only one side of a pool cover by heat sealing. A webbing member  55   a  and a filler member  52   a  are disposed adjacent to the edge  51   a  of a pool cover  50   a . Webbing member  55   a  has at least one side  53   a  that has a surface of vinyl or other thermoactive material. 
     As shown in  FIGS. 7A–B , webbing member  55   a  is wrapped around filler member  52   a  to form a bead  62   a . The top portion of webbing  55   a  forms a flap  57   a  lying in contact with the top surface of pool cover edge  51   a.  The bottom portion  54   a  of webbing  55   a  is disposed in contact with the undersurface  53   a  of webbing member  50   a . The adjoining surfaces of  54   a  and  55   a  may be connected together by heat sealing, stitching or other procedure sufficient to secure  54   a  to the portion of flap  57   a  as shown. The adjoining surfaces of flap  57   a  and pool cover edge  51   a  are connected together by heat sealing, using a procedure substantially the same as previously described with respect to  FIGS. 5A–5C  and  6 A– 6 B. 
     One advantage to the implementation disclosed in  FIGS. 7A and 7B  is that only a single heat seal need be formed between two adjoining surfaces. This approach will be effective if the single heat seal is strong enough to withstand the wear and stress applied to the pool cover and webbing. 
       FIG. 8  is another view showing pool cover  50  attached to the heat sealed webbing  55  with a beaded edging  62 . Flap  57  of webbing member  55  is securely heat sealed to pool cover  50 . Filler element  52  is preferably a ¼ inch woven rope, but could be made of a dacron vinyl thread or any other durable material that will hold its shape when subjected to mechanical stress and tension. 
       FIGS. 9–15  show one implementation of an apparatus  70  used to form the heat sealed web element  55 . As best seen in  FIGS. 10–12 , flaps  57  and  58  are wrapped around filler element  52  and extended adjacent to the pool cover edge  51 . An upper heater element  76  forces hot air through nozzle  78  and out of nozzle spout  80 . Spout  80  rides between upper flap  57  and the upper surface of pool cover edge  51  to apply heat to both surfaces. Similarly, a lower heater element  82  forces hot air through a nozzle  84  and out of nozzle spout  86  between lower flap  58  and the under surface of pool cover edge  51 . 
     Looking particularly at  FIG. 12 , the hot air partially melts the adjoining surfaces of the pool cover edge  51  and the inside surfaces  59  and  60 , respectively, (shown in  FIG. 5B ) of upper flap  57  and lower flap  58 , respectively, so that these surfaces can form heat welded connections. As seen in  FIGS. 10 and 11 , upper roller  72  and lower roller  74  press flaps  57  and  58  against pool cover edge  51  while said surfaces are heated to form secure heat seals between the surfaces, so that the web element  55  is firmly attached to the pool cover edge  51 . 
     The hot air generated by heater elements  76  and  82  may be heated to a temperature between approximately 1000–1300 degrees Fahrenheit. Fifty pounds or more of pressure may be applied by the rollers  72  and  74  to the heated flaps  57  and  58 . The result is an extremely strong heat weld or seam in the heat sealed web element  55  that will withstand forces that might be expected to be applied to the pool cover  50 . The heat seal is not susceptible to deterioration from the sunlight or from chemical erosion. Methods of constructing such an apparatus are well known to those of skill in the art. 
     Moreover, the heat sealed web structure  55  above and below the pool cover edge  51 , as described above, is formed in one pass of the materials through the apparatus. Heat is applied to the webbing flaps  57  and  58  at substantially the same time, and the rollers  72  and  82  confirm the heat seals to complete the sealing operation. This one pass procedure minimizes the amount of labor required to form the heat sealed webbing. 
     In operation, an operator may feed the webbing member  55  and the pool cover  50  to mate with each other, as further shown in  FIGS. 10–12  and as described above. The apparatus may be manned by one person feeding the bead  52 , the webbing member  55 , and the pool cover edge  51  between rollers  72  and  74 . Accordingly, the entire structure may be quickly and efficiently formed along the edge of a pool cover  50 . 
     Referring now to  FIGS. 13 and 14 , it can be seen that the nozzles  78  and  84  may be rotated away from the rollers  72  and  74  when the apparatus is not in use. This action makes it easier to set up the apparatus for operation and to clean the apparatus. When the apparatus is ready for operation, the nozzles  78  and  84  are rotated back into an aligned position, as best seen in  FIG. 10 . Then nozzles  78  and  84  are slid forward toward the rollers  72  and  74  until they are in close proximity therewith, as best seen in  FIG. 11 . 
       FIG. 15  is another perspective view showing the apparatus  70  in operation. Heater element  76  and nozzle  78  have been rotated into alignment with roller  72 . Nozzle  78  is twisted slightly so that nozzle spout  80  will slip beneath webbing flap  57  without nozzle  78  interfering. A first guide member  92  guides flap  57  toward the roller  72 . A second guide  94  directly in front of roller  72  maintains a slight separation between flap  57  and the edge  51  of pool cover  50 . This separation provides a space for nozzle spout  80  to inject hot air into the space to partially melt the vinyl undersurface of flap  57  and the top surface of pool cover edge  51 , as previously shown in  FIGS. 10–12 . 
     An substantially identical operation occurs on the underside of apparatus  70 . Although not shown, heater element  82  and nozzle  84 , seen in  FIGS. 10 ,  11  and  13 , have also been rotated in alignment with roller  74 . Guides (not shown) similar to guides  92  and  94  direct the webbing  55  to roller  74 , maintaining a space for nozzle spout  86  to inject heated air to partially melt the appropriate surfaces just prior to roller  74  applying pressure to confirm the heat seal between the top surface  60  of flap  58  and the under surface of pool cover edge  51 . 
     It is understood that variations of the above preferred implementation might be employed within the scope of the disclosure. For example, in some cases the hot air coming from nozzle foot  80  and nozzle foot  86  may provide too much heat to the flaps  57  and  58  and the pool cover edge  51 . In such case the upper or lower mechanisms may be offset by a a sufficient distance (not shown) to allow cooling of the flaps  57  and  58  and pool cover edge  51  between applications of hot air from the nozzle feet  80  and  86 . 
     Thus, the upper mechanisms, including roller  72 , heater element  76 , nozzle  78  and nozzle foot  80  might be offset longitudinally along the service line of the pool cover edge  51  by some distance from the lower roller  76 , heater element  82 , nozzle  84  and nozzle foot  86 . In the interim space, cool air may be applied to the flaps  57  and  58  and the pool cover edge  51  to allow the bond between the lower flap  58  and the pool cover edge  51  to cool and bond. Conversely, the hot air could be applied first to the upper flap and pool cover edge  51  and then the lower flap  58  and pool cover edge  51  could be bonded further down the service line of the pool cover edge. 
     Although the above applications are representative of the present disclosure, other applications will be apparent to those skilled in the art from a consideration of this specification and the appended claims, or from a practice of the applications of the disclosure. It is intended that the specification and applications therein be considered as exemplary only, with the present disclosure being defined by the claims and their equivalents.

Technology Classification (CPC): 4