You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of domestic priority of U.S. provisional patent application No. 60/351,003 filed on Jan. 25, 2002. The contents of the above noted document are incorporated herein by reference. 

   TECHNICAL FIELD 
   The present invention generally relates to swimming pools and, more particularly, to stairs and other accessories therefor. 
   BACKGROUND ART 
   Various stair and step systems have been created for swimming pools. For instance, U.S. Pat. No. 5,644,873, issued to Bourgault on Jul. 8, 1997, and U.S. Pat. No. 6,000,494, issued to Wilson on Dec. 14, 1999, both disclose stair systems preferably used with aboveground pools. In designing stair or step systems for swimming pools, such systems must adapt to the various installations, such as the type of pool (i.e., aboveground pool/in-ground flat-bottom pool/dish-bottom pool, seat width of the pool), the direct environment of the pool (i.e., wooden deck), etc . . . The pools also have varying depths, and the floor level adjacent to an aboveground pool may vary. Accordingly, all these factors must be taken into account in designing a versatile stair system for swimming pools. 
   SUMMARY OF INVENTION 
   It is a feature of the present invention to provide swimming pools stairs generally adapted for all types and configurations of pools. 
   Therefore, in accordance with a broad aspect of the present invention, there is provided a stair portion for a stair assembly for a swimming pool, comprising a bottomless hollow body having lateral surfaces and a top surface defining steps, the bottomless hollow body adapted to be received in a pool with at least one bottom edge of the lateral surface lying against a bottom of the pool such that a user person can move in or out of the pool using the steps, the bottomless hollow body adapted to be connected to a pool connector portion for being secured adjacent to a sidewall of the pool, the bottomless hollow body adapted to be nested with another one of the bottomless hollow body, so as to facilitate at least one of transportation, warehouse storage, maneuverability and installation in a body of water. 
   In accordance with a further broad aspect of the present invention, there is provided a stair assembly for a swimming pool comprising a stair portion defining steps and adapted for being received in a pool, said stair portion having a ballast; and a pool connector portion connected to said stair portion for securing said stair portion adjacent to a sidewall of the pool, said pool connector portion being adapted to be secured to a ledge of the pool and having a translationary coupling with said stair portion for vertical adjustment therebetween as a function of one of a height of a sidewall and a depth of the pool. 
   In accordance with a still further broad aspect of the present invention, there is provided a stair portion for a stair assembly for a swimming pool, comprising a hollow body having lateral surfaces and a top surface defining steps, one of said steps having a ballast receiving portion, the hollow body adapted to be received against a bottom of a pool such that a person can move in or out of the pool using the steps, the hollow body adapted to be connected to a pool connector portion for being secured adjacent to a sidewall of the pool; and a ballast adapted to be received in the ballast receiving portion. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: 
       FIG. 1  is a perspective view of swimming pool stairs in accordance with the present invention; 
       FIG. 2  is a side elevational view of the swimming pool stairs; 
       FIG. 3  is an exploded view showing a removable ballast compartment in position for being installed on the swimming pool stairs; 
       FIG. 4  is an enlarged perspective view of the swimming pool stairs with a ladder, as installed on a swimming pool; 
       FIG. 5  is an enlarged perspective view of the swimming pool stairs as installed on a deck adjacent to the swimming pool; 
       FIG. 6  is an exploded side elevational view of the swimming pool stairs with a ladder; 
       FIG. 7  is a side elevational view of a stacked stair portion of the swimming pool stairs of the present invention; 
       FIG. 8  is a perspective view of a pivoting adjustment of a pool connector portion of the swimming pool stairs; 
       FIG. 9  is a side elevational view of another embodiment of the swimming pool stairs; and 
       FIG. 10  is an enlarged perspective view of a ballast in accordance with another embodiment of the present invention. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   Referring to the drawings, and more particularly to  FIG. 1 , swimming pool stairs in accordance with the present invention are generally shown at  10 . The swimming pool stairs  10 , hereinafter stairs  10 , are shown installed in an aboveground pool  12  having a sidewall  14  and a bottom surface  16 . Typical sidewalls of aboveground pools have heights of 48″, 52″ or 54″. A ledge  18  (i.e., seat) covers an upper edge of the sidewall  14 , as typically found on aboveground pools. Although the stairs  10  are illustrated in an aboveground pool, they are also adapted for being used with in-ground pools. For the clarity of the illustrations, water has been removed from the pool  12 . 
   The stairs  10  have a stair portion  20 , handrails  22  and pool connectors  24 , and these are all interconnected by pairs of uprights  26 ,  28  and  30 . More particularly, the uprights  26  connect the stair portion  20  to a bottommost point of the handrails  22 . The pool connectors  24  are slidingly engaged on the uprights  26 . The uprights  28  connect the pool connectors  24  to the stair portion  20 , and the uprights  30  connect the uppermost point of the handrails  22  to the pool connectors  24 . The uprights  28  are optional and thus not present on the stairs  10  illustrated in  FIGS. 2 and 9 . 
   Still referring to  FIG. 1 , the stair portion  20  is shown having four steps  32 , which are separated by risers  34 . The steps  32  have an anti-skid surface. The anti-skid surface of the steps  32  may consist of small protuberances molded onto the steps  32 , or of similar means, for instance, an abrasive such as sand bonded to the anti-skid surface of the steps  32 , as depicted in FIG.  1 . Lateral walls  36  and rear wall  38  generally complete the shape of the stair portion  20 . The stair portion  20  is bottomless, but defines a peripheral lip  40  on a bottom edge thereof. The peripheral lip  40  is provided in order to solidify the stair portion  20 . As the stair portion  20  does not have a bottom, the peripheral lip  40  enhances the stiffness of the stair portion  20 . Also, the peripheral lip  40  provides a greater surface of contact between the stair portion  20  and the bottom surface  16  of the pool  12 . As illustrated in  FIG. 2 , the bottom rear end of the stair portion may be beveled, as shown by  25 , to accommodate an angled edge of the pool  12 . 
   As best seen from  FIG. 1 , the lateral walls  36  define a sinuous shape. It is pointed out that the sinuous shape is for strengthening the stair portion  20  and for ornamental purposes, and is such that the steps have an arcuate shape. Moreover, the sinuous shape of the lateral walls  36  will facilitate the stackability of the stair portions  20 , as will be described hereinafter. However, the lateral walls  36  and the steps  32  could also have straight edges or other ornamental configurations. The stair portion  20  is typically molded and consists of a plastic material, which preferably has a density greater than water so as to avoid floating and thus sinking to the bottom of the pool  12 . A removable ballast compartment  42  is connected to and integrated into a bottommost one of the steps  32  and is shaped so as to be snugly received in a corresponding cavity of the bottommost step  32  so as to serve as a step when fitted in the cavity. An example of a possible configuration is illustrated in  FIG. 3 , wherein the ballast compartment  42  is received in a cavity  41  in the stair portion  20 . Other possible embodiments include a ballast in the shape of a cylinder  142 , as shown in  FIG. 10 , received in a corresponding cavity  141 . The cylinder  142  has a flanged head  143  so as to be retained in the cavity  141  by gravity. 
   In the embodiment of  FIG. 3 , the removable ballast compartment  42  is provided for receiving a ballast that will stabilize the stair portion  20  on the bottom surface of the pool  12 . In the prior art, sandbags were used as ballasts as the stair portions usually defined inner cavities with a bottom surface thereof. The ballasts are advantageously positioned in the removable ballast compartment  42 , which is easily installed on or removed from the stair portion  20 , thereby facilitating the installation and the displacement of the stair portion  20  in the pool  12 . In the prior art stairs, the installation of ballasts within inner cavities, on the bottom surface, was hard to achieve. Such inner cavities also required either a substantial amount of time for the removal of water therefrom, or the lifting of heavier weights due to the water remaining in the inner cavities. 
   The stair portion  20  of the present invention, with its bottomless, will easily be maneuverable in the water, yet be heavy enough to sink to the bottom of the pool  12 . As seen in  FIG. 3 , once the stair portion  20  is positioned in the swimming pool  12 , the ballast compartment  42  is positioned in the cavity  41 , thereby anchoring the stair portion  20  to a desired position in the pool  12 . The same steps of installation apply to the cylinder-shaped ballast  142  of FIG.  10 . The ballast in the ballast compartment  42  may be sand, gravel, or any heavy material. The ballast compartment  42  has a lip  43  at the rear of a bottom surface thereof, for engaging into a groove  45  in the cavity  41  of the stair portion  20 , whereby horizontal displacement of the ballast compartment  42  is prevented. 
   As best seen in  FIG. 7 , the transportation and the warehousing space savings aspects are improved by the bottomless configuration of the present invention, as stair portions  20  may be stacked in a nested manner one within the other. Transportation costs are greatly reduced as the result of the nesting, which reduces the volume taken by the stair portions  20 . In order for an efficient stacking of the stair portions  20 , the latter are shaped in a taper from bottom to top, although not clearly visible in FIG.  1 . As mentioned above, the sinuous shape of the lateral walls  36  facilitates the stacking. The strength of the stair portion  20  is enhanced by the sinuous shape, whereby deformation is reduced. Accordingly, when stair portions  20  are nested one onto the other, they will be more readily separated from one another if they do not deform. 
   Still referring to  FIG. 7 , packages of hardware are generally shown at H, positioned in the cavity of the bottommost stair portion  20 . The packages of hardware H include the handrails  22  and pool connectors  24 , the uprights  26 ,  28  (if applicable) and  30 , the necessary fasteners for assembly, and other components if applicable. Accordingly, transportation volume is optimized. Moreover, it is possible to stack other stair portions  20  in a reversed position in top of the first stack of stair portions  20 , as shown at  20 ′. For instance, two stacks of four stair portions  20  on top of each other and positioned on a pallet is an optimal transport configuration. 
   The top two steps  32  of the stair portion  20  have on opposite sides holes for receiving therein the pairs of uprights  26  and  28 . As seen in  FIG. 1 , the uprights  26  and  28  are secured to the stair portion  20  using typical fasteners such as screws  21 . It is also conceivable that, the handrails  22 , the pool connectors  24  and the uprights  26 ,  28  and  30  may be immovably fixed to the deck D and the uprights  26  and  28  simply extend in their respective holes  26 ′ and  28 ′ formed in their respective steps  32 , such that the stair portion  20  can slide along the uprights  26  and  28 . This would facilitate the installation and the removal of the stairs  10 . 
   As seen in  FIGS. 1 and 5 , the pool connectors  24  have an elongated body  44  with a triangular support portion  46  rising upwardly away from the pool  12 . Opposed ends of the elongated body  44  comprise through bores  48  and  50 , respectively adapted to receive the uprights  26  and the uprights  30 , whereas a middle portion of the elongated body  44  receives the uprights  28 . Due to the triangular support portion  46 , the pool connectors  24  have a large contact surface with the uprights  30 , thereby increasing the stability in the connection therewith. A bottom edge surface  52  of the elongated body  44  sits on the ledge  18  of the pool  12 . Channels  54  are provided just above the bottom edge surface  52 , opposite the ledge  18 , thereby defining a flange  56  that allows the pool connector  24  to be fixed to the planks of a deck D. More precisely, the flange  56  has a rounded portion  58  that surrounds a rear end of the pool connectors  24 . Although the pool connectors  24  are illustrated as being fixed to deck D, they are also adapted for being fastened to concrete, in the case of an in-ground pool. The channels  54  are provided to receive opposed ends of a ladder top  76 , that will sit on the seat  18 . Holes are provided for securing the ladder top  76  in the channels  54 . 
   Returning to  FIG. 1 , the handrails  22  are shown both connected to the top ends of uprights  26  and  30 . The handrails are obviously provided for helping a person getting into and out of the pool  12 . The illustrated handrails  22  have a handle portion  64 , and are typically molded with a friction surface so as to enable a solid grasp by a user of the stairs  10 . The handrails  22  are fixed to the top ends of the uprights  26  and  30 . 
   In the preferred embodiment of the present invention, the vertical positioning of the stair portion  20  is adjustable with respect to the pool connectors  24  so as to adapt the stairs  10  to various heights of the sidewall  14  in the case of an aboveground pool. The stairs  10 , adjustable vertically, do not have the uprights  28 . As mentioned previously, the uprights  26  and  30  can slide in the pool connectors  24 . 
   Once the stair portion  20  has been positioned at a desired position in the pool  12 , the assembly of the uprights  26  and  30  with the handrails  22  and the pool connectors  24  is disposed on the seat  18 , with the uprights  26  received in the corresponding holes  26 ′ of the stair portion  20 . As the pool connector  24  is in translational relation with the uprights  26  and  30 , the vertical adjustment is readily performed by sliding the uprights  26  and  30 , and thus the handrails, into a desired vertical position. As illustrated in  FIG. 8 , the stairs  10  without the uprights  28  enable pivoting of the handrails  22 /pool connectors  24  about an axis of the uprights  26 , as illustrated by arrows A. Thereafter, the pool connectors  24  are fastened to the deck D, as described previously. 
   Still referring to  FIG. 2 , the vertical adjustment described above is easily achieved for an aboveground pool having a deck D coplanar with the ledge  18  of the pool. There are various ways to achieve the vertical adjustment in an in-ground pool. For instance, a receiving hole may be drilled in the concrete so as to enable the vertical displacement of the uprights  30 . Also, the length of the uprights  30  may be calculated prior to installing the stairs  10  in the pool, whereby the uprights  30  may be cut to an appropriate length so as to be coterminous with the ground level. 
   Referring now to  FIGS. 4 and 6 , the stairs  10  are shown provided with other accessories, namely a ladder  66  to be used typically with an aboveground pool that does not have a deck D adjacent thereto. The ladder  66  typically has horizontal bars  68  held between a pair of stringers  70 . The ladder  66  has housings  72  on top ends of the stringers  70 . The housings  72  define cylindrical cavities (not shown) adapted for receiving therein bottom end portions of the uprights  30 . Screws  74  allow the ladder  66  to be fastened to bottom end portions of the uprights  30 . 
   Still referring to  FIGS. 4 and 6 , the stairs  10  are provided with the ladder top  76  and ladder handrails  78 . The ladder top  76  ensures a transition between the ladder  66  and the stair portion  20 . The ladder top  76  is a generally flat plate having no sharp edges and sitting on the ledge  18  of the aboveground pool  12 . As mentioned previously, the ladder top  76  is received in the channels  54 , and fasteners  55  are used to fix the ladder top  76  to the pool connectors  24 . The ladder top  76  can be strapped to the seat  18  to stabilize the assembly. Obviously, fasteners such as screws could be used to fasten the ladder top  76  to the seat  18 . 
   Although not illustrated herein, it is pointed out that the stairs  10  may be adjustable vertically even if they are provided with the ladder  66 . In such a case, the bottom  16  will most frequently be coplanar with the ground level at which the ladder  66  will be resting. Accordingly, both the stair portion  20  and the ladder  66  are vertically adjusted by the sliding relation between the pool connector  24  and the uprights  26  and  30 , and using the fastener screws  62 . The fastener screws  62  secure the pool connectors  44  in position to the uprights  26  and  30 . 
   It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiment described herein, provided such modifications fall within the scope of the appended claims.

Summary:
A stair portion for a stair assembly for a swimming pool, comprising a bottomless hollow body having lateral surfaces and a top surface defining steps. The bottomless hollow body is adapted to be received in a pool with bottom edges of the lateral surface lying against a bottom of the pool such that a user person can move in or out of the pool using the steps. The bottomless hollow body is adapted to be connected to a pool connector portion for being secured adjacent to a sidewall of the pool. The bottomless hollow body is adapted to be nested with another bottomless hollow body, so as to facilitate transportation, warehouse storage or maneuverability in a body of water.