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: 
BACKGROUND 
     1. Field of the Invention 
     The present invention relates to spiral staircase and handrail assemblies, and more particularly, to systems and methods used for installing such assemblies. 
     2. Description of the Related Prior Art 
     Spiral staircase designs are well known in the art. For safety reasons, virtually all spiral staircase designs include accompanying handrails. While continuous lengths of metal are often preferred for handrails due to aesthetic considerations, it has been found difficult to utilize such because precision support pieces are routinely required for proper alignment of the rail above the treads of the staircase. To that end, a wide variety of devices have been introduced for securing the handrail to the treads of the staircase by balusters or posts, but the majority of these devices are difficult to work with because they require precise forming and positioning of not only the handrail but also of the support and attachment mechanisms for the handrail. The alternative to this can be to form screw bores and the like in the pieces on site when installing the staircase and handrail. However, even in such cases, proper installation and fitting of the handrail can be found to be difficult and time-consuming processes. Furthermore, such attachment mechanisms are often found to be quite complex and expensive. 
     An additional problem with handrails for spiral staircases of the prior art is that the sides of the rail can be bendable to a fault if too long and quite rigid if too short. As such, when using such extreme lengths, the materials that can be used can be limited. For example, it is not uncommon when attempting to form curvature in a lengthy handrail, so as to align it with a spiral staircase, to end up with one or more undesirable bends over its extent. To address this, in some designs, handrails have been conventionally formed of multiple pieces. However, such designs can still be found to complicate matters as the separate pieces, in light of their shortened length, are more difficult to bend with the requisite curvature. 
     The present invention solves these and other problems. 
     SUMMARY OF THE INVENTION 
     Embodiments of the invention provide a modular spiral staircase assembly that involves a handrail of one or more sections and a series of slide members each configured to form a link between both a baluster and the handrail of the staircase. The use of such slide members enables initial ease with respect to positioning of the balusters along the extent of the handrail and subsequent secure locking of such balusters in position with respect to the handrail for alignment purposes with corresponding treads of the staircase. Additionally, using such slide members along the extent of the handrail provides the installer ready-made tools for progressively shaping the extent of the handrail so as to align it with the curvature of the staircase. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a fragmentary perspective front view of a lower portion of a spiral staircase in accordance with certain embodiments of the invention. 
         FIG. 2  is a fragmentary side view of the spiral staircase of  FIG. 1  that is generally taken along the line and in the direction of the arrows  2 - 2  of  FIG. 1 . 
         FIG. 3  is a side view of an intermediate baluster of the spiral stairway of  FIG. 1  with vertical intermediate parts broken away in accordance with certain embodiments of the invention. 
         FIG. 4A  is a side perspective view of an assembly drawing for a baluster being operatively coupled to a handrail section via a slide member in accordance with certain embodiments of the invention. 
         FIG. 4B  is a side cross-sectional view of the assembly of the baluster, slide member, and handrail of  FIG. 4A  in accordance with certain embodiments of the invention. 
         FIGS. 4C and 4D  are cross-sectional views of the assembled elements of  FIG. 4B  that are taken along the lines and in the directions of the arrows  4 C- 4 C and  4 D- 4 D, respectively, of  FIG. 4B . 
         FIG. 5A  is a side cross-sectional view of an alternate assembly of a baluster being operatively coupled to a handrail section via a slide member in accordance with certain embodiments of the invention. 
         FIG. 5B  is a cross-sectional view of the assembled elements of  FIG. 5A  that is taken along the line and in the direction of the arrows  5 B- 5 B of  FIG. 5A . 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description should be read with reference to the drawings, in which like elements in different drawings are numbered identically. The drawings depict selected embodiments and are not intended to limit the scope of the invention. It will be understood that embodiments shown in the drawings and described below are merely for illustrative purposes, and are not intended to limit the scope of the invention as defined in the claims. 
       FIG. 1  shows a fragmentary perspective front view of a lower portion of a spiral staircase in accordance with certain embodiments of the invention. The spiral staircase, generally designated as  10 , includes a central column  12 . As shown, the column  12  can generally include a base member and a spacer  14  thereon. In certain embodiments, as shown, the column  12  further includes a plurality of collars  16  and spacer rings  18  mounted in a vertically stacked relationship, with each collar  16  being positioned between a pair of the spacer rings  18 . Each collar  16  mounts a tread  20  to extend radially outwardly there from, with successive treads  20  of the staircase  10  being vertically and angularly offset from each other. As shown, the staircase  10  includes a plurality of balusters  22  operatively linking the treads  20  to a handrail section  24  of the staircase  10 . 
     To that end,  FIG. 2  illustrates a fragmentary side view of the spiral staircase  10  that is generally taken along the line and in the direction of the arrows  2 - 2  of  FIG. 1 . As shown, in certain embodiments, a first baluster  22 , or lowermost of the balusters, is operatively coupled to a front corner portion  20   a  of a first of the treads  20 , while other intermediate balusters  22  are each operatively coupled to a rear portion  20   b  of one of the treads  20  and front portion  20   a  of a next vertically successive tread  20 . Connection means between the balusters  22  and the treads  20  are provided via one or more fasteners  26 , which in some cases, can be screws or bolts. Therefore, in certain embodiments, as shown in  FIG. 2 , the fasteners  26  are used for operatively coupling each of the balusters  22  to one or more of the front corner portions  20   a  and the rear corner portions  20   b  of the treads  20 . It should be appreciated that the sizes and quantities of the fasteners  26  used for operatively coupling the balusters  22  to the treads  20  can be variably specified. 
       FIG. 3  shows a side view of one of the intermediate balusters  22  of the spiral stairway  10  with vertical intermediate parts broken away in accordance with certain embodiments of the invention. With reference to  FIGS. 2 and 3 , in certain embodiments, each of the fasteners  26  operatively coupling the intermediate balusters  22  to the front and rear corner portions  20   a ,  20   b  of the corresponding treads  20  are positioned within baluster slots  28   a ,  28   b , respectively. The slots  28   a ,  28   b  are vertically elongated to permit limited vertical adjustment of the baluster  22  relative to the treads  20  before the fasteners  26  are tightened to retain the baluster  22  in a fixed position relative to the treads  20 . 
     In certain embodiments, the handrail section  24 , as shown in  FIG. 1 , is made up a continuous piece, and as described hereafter, when being installed using the assembly and method of the present invention, is generally curved about the diameter of the outer edges of the treads  20  vertically ascending about the central column  12 . As a result, the handrail section  24  is longer in extent than the flat diameter of the treads outer edges as the section  24  is both adaptively curved in the direction of elongation and inclined upwardly to extend angularly, in simple applications, through at least 20 degrees and in more complicated applications, through at least 180 degrees and possibly to extend angularly through substantially more than at least 360 degrees. For convenience, the direction of elongation hereinafter will be referred to as “longitudinal”. 
       FIG. 4A  illustrates a side perspective view of an assembly drawing for operatively coupling one of the balusters  22  to the handrail section  24  in accordance with certain embodiments of the invention.  FIG. 4B  shows a side cross-sectional view of the assembly of the elements of  FIG. 4A  in certain embodiments of the invention.  FIGS. 4C and 4D  illustrate cross-sectional views of the assembled elements of FIG. B that are taken along the lines and in the directions of the arrows  4 C- 4 C and  4 D- 4 D, respectively, of  FIG. 4B . With reference to  FIGS. 4C and 4D , the handrail section  24  is generally U-shaped in transverse cross section and when used, is generally oriented to provide a downward facing channel  30  extending the length of the section  24 . In certain embodiments, the handrail section  24 , in its non-assembled condition, has its central axis of elongation along the lines L-L along its length and has little to no angular variation along such axis. The rail section  24  includes a top web  32  with a pair of side walls  34  and  36  extending substantially perpendicular from the top web&#39;s outer edges, thereby forming the channel  30 . As shown, the side walls  34  and  36 , at their lower ends, each includes a corresponding flange  38  and  40 , respectively. The flanges  38 ,  40  are joined to the side walls  34 ,  36 , respectively, to extend transversely inwardly toward each other and are spaced transversely to limit the opening to the handrail section&#39;s channel  30 . 
     With further reference to the handrail section  24 , joined to each of its upper corner portions and adjacent juncture of the side walls  34 ,  36  and the web  32  are respective flange pairs  42 ,  44 . The flange pairs  42 ,  44  define respective channels  42   a ,  44   a  there between, each of which extends the length of the rail section  24 . The channels  42   a ,  44   a  are configured to seat pins  46  therein to align multiple rail sections  24 , as further described below. Such pins  46 , once seated in the channels  42   a ,  44   a  would also function to increase the structural integrity of the aligned handrail sections  24 . 
     Used in part to secure the upper end of the baluster  22  to the handrail section is a slide member  48 . Like the handrail section  24 , the slide member  48  is generally U-shaped in transverse cross section, and when in use, is generally oriented to provide a downward facing channel  50 . The slide member  48  includes a top web  52  with a pair of parallel side walls  54  and  56  extending substantially perpendicular from the web corners, thereby defining the channel  50 . The longitudinal length of the slide member  48  is greater than its transverse dimension and, in certain embodiments, is less than twice than the corresponding length dimension of the baluster  22 . 
     As can be appreciated from  FIG. 4B , in certain embodiments, the slide member  48  is pivotally coupled to the upper end of the baluster  22 . As shown from  FIG. 4A , the slide member  48  is placed over the upper end of the baluster  22  so as to align their respective pairs of holes  58 ,  60  and  62 ,  64 . With the pairs of holes  58 ,  60  and  62 ,  64  so aligned, a pin  66  can be passed in the hole pairs so as to extend through each, as shown in  FIG. 4D . As a result, the slide member  48 , via the pin  66 , can be pivoted relative to the baluster  22 , as shown in  FIG. 4B . 
     Following coupling of the slide member  48  with the upper end of the baluster  22 , the slide member  48  is inserted within the channel  30  of the handrail section  24 . Once the slide member  48  is inserted (and as shown, entirely situated) within the rail section  24 , the side walls of the rail section  24  serve to not only conceal the pin  66 , but also prevent the pin  66  from transversely moving out of the respective slide member holes  58  and  60 . Further, the side walls  54 ,  56  of the slide member  48  are configured to respectively adjoin with the side walls  34 ,  36  of the rail section  24 . As shown in  FIGS. 4C and 4D , in certain embodiments, such adjoining occurs through mating of the ends of the slide member side walls  54 ,  56  and the flanges  38 ,  40  of the handrail section  24 , respectively. In certain embodiments, as shown, the ends of the slide member side walls  54 ,  56  define narrowed portions  68 ,  70 , respectively, that seat in corresponding grooves  72 ,  74  defined by the flanges  38 ,  40 , respectively. While the ends of the slide member side walls  54 ,  56  and the flanges  38 ,  40  of the handrail section  24  are mated, the slide member  48  can still be slidably adjusted within the channel  30  of the rail section  24 . 
     With reference to  FIG. 4B , upon sliding the slide member  48  within the channel  30  so as to properly position its coupled baluster  22  relative to corresponding treads  20  of the spiral staircase  10 , a threaded fastener  76 , such as a bolt, is threaded through an aperture  78  in the slide member  48  to lock it in place within the channel  30 . As further illustrated, in certain embodiments, the aperture  78  is defined in the top web  52  of the slide member  48  in order for the fastener  76 , once extended there through, to contact a corresponding inner surface of the handrail section  24  overlaying the top web  52 . In certain embodiments, as shown, the aperture  78  supports a threaded coupling  79  through which the fastener  76  is extended; however, it should be understood that there are a variety of other ways to provide a threaded entry at the aperture  78  short of requiring said coupling  79 . It should be appreciated that once the slide member  48  is so secured to the handrail section  24 , the baluster  22  coupled to the slide member  48  can be used as a lever to move, and thereby shape the handrail section  24  according to the curvature of the treads  20  of the spiral staircase  10 , as will be further described. After shaping the handrail section  24  in such manner, the lower end of the baluster  24  can be mounted to its corresponding tread(s)  20 , as described above. 
       FIG. 5A  shows a side cross-sectional view of the baluster  22  being operatively coupled to the handrail section  24  via an alternate slide member  48 ′ in accordance with certain embodiments of the invention.  FIG. 5B  illustrates a cross-sectional view of the assembled elements of  FIG. 5A  that is taken along the line and in the direction of the arrows  5 B- 5 B of  FIG. 5A . As shown, one distinction between the assemblies of  FIG. 4B  and  FIG. 5A  are the use of an alternate slide member  48 ′, which has its channel  50 ′ directed up toward the channel  30  of the handrail section  24 . Such a configuration can have many benefits as it confines the hardware (e.g., the threaded fastener  76 ) within the channel  50 ′ for aesthetic purposes (which it should be noted also occurs with the assembly of  FIG. 4B  but to a lesser extent) and closing the channel  50 ′ from contaminants. Another distinction is the use of a bore  77  in securing the baluster  22  thereto without further hardware. Benefits would involve enhanced ease of attachment between the baluster  22  and the slide member  48  as well as allowing for significant tolerance for a “mid-baluster” height, i.e., the height portion of the baluster  22  not needed can extend into the channel  50 ′. This is important because such mid-baluster lengths often vary based on the adjusted rise of each tread  20 . For example, in the case of using more than one “mid-balusters”, the restraint on height is always more so as you come to the next successive mid-balusters. Accordingly, mid-balusters can be more fully utilized with such assembly without requiring the installer to re-cut the mid-balusters. 
     Regarding construction of the spiral staircase  10 , the process is as follows. The central column  12  is installed and is configured with a plurality of collars  16  offset by spacer rings  18 . As described above, the treads  20  are mounted on the collars  16  and are generally situated in vertical relationship such as exemplified with respect to  FIG. 1 . A first (lowermost) baluster  22  is subsequently installed, initially by being secured to the lowermost (first) tread by the fastener(s)  26  extended through one of the slots  28   a  or  28   b  in the lower portion of the baluster  22 . A first slide member  48  is connected to the upper end of the first baluster  22  via the pin  66 , and a first rail section  24  is then moved in a general longitudinal direction so as to have the first slide member  48  extend into the channel  30  of the handrail section  24  and slide there through its extent until the first slide member  48  reaches its desired position adjacent the descending end of the rail section  24 . In turn, the threaded fastener  76  is tightened to abut against the inner surface of the rail section  24  to retain the first slide member  24  in fixed position relative to the first rail section  24 . 
     Additional slider members  48  are pivotally attached to corresponding balusters  22  and one or more of such additional slider members  48  (with balusters  22  connected thereto) are inserted into the first rail section channel  30 . In certain embodiments, the additional slide members  48  may be moved along the rail section  24  until they are approximately at the desired longitudinal spacing from one another. In turn, in certain embodiments, the threaded fastener  76  for at least the second slide member  48  is tightened to retain such slide member  48  at its desired longitudinal position relative to the rail section  24 . In other embodiments, the threaded fasteners  76  for each of the additional slide members  48  may be also tightened to retain the slide members  48  at each of their desired longitudinal positions in the rail section channel  30 . 
     With the second slide member  48  secured in desired channel position of the rail section  24 , the rail section  24  is pivoted so as to shape a corresponding segment of the rail section  24 . Regarding such corresponding rail section segment, its length would extend from the pivot axis at the pin  66  of the previously-secured first baluster  22  (or point of entry in the aperture  77  if using the slide member  48 ′) up to the secured second slide member  48 . In shaping the rail section segment, the baluster  22  (the second baluster) is used as a lever to twist the segment of the rail section  24  by manually moving the lower end of the lever generally about the longitudinal axis L-L of the rail section  24  toward the central column  12 . Such twisting creates a force applied to the respective flanges  38 ,  40  of the rail section proximate to the second slide member  48  and its corresponding threaded fastener  76  (against rail section  24 ) such that the pivot and pin  66  of the second slide member  48  is moved to extend generally horizontally and radially toward the vertical central axis of the column  12  and the baluster  22  is moved into abutting relationship to the walls of the second and third lowermost treads  20 . That is, the lowest baluster  22  (not yet secured to its corresponding treads  20 ) can be manually moved to twist the rail section  24  and then vertically adjusted (if necessary) relative to the lowermost (first) and the next to the lowermost (second) tread  20  to the desired vertically adjusted position and if necessary, the next to the lowermost tread  20  angularly adjusted. 
     In turn, the fastener(s)  26  are tightened to retain second baluster  22  extending vertically (substantial at 90 degrees to the horizontal) in the vertical adjusted position relative to the treads  20  and, if necessary, the threaded fastener  76  is loosened and the slide member  48  (second) longitudinally readjusted and then the fastener  76  re-tightened to retain the slide member  48  (second) in the desired position relative to the rail section  24 . Thus, by having the elongated slots  28   a ,  28   b  in the lower portion of the second baluster  22 , the second baluster  22  can be vertically adjusted and secured in a fixed position relative to the second and third treads  20  such that the segment of the rail section  24  between the first and second balusters  22  is retained at the preselected angle of inclination and elevation position for that part of the installed handrail section  24 . It is noted that prior to the fasteners  26  being tightened, the next to lowermost tread is rotated about the central column to a final rotated position, if not already in such a position, the fasteners  26  being loosened and tightened to retain the second lowermost tread  20  in a fixed position relative to the central column  12 . 
     Thereafter the next to lowermost baluster (third baluster)  22  is moved and twisted to bend the rail section  24  and the necessary above mentioned steps are taken whereby this baluster  22  can be and is connected to the walls of the second and third lowermost (second and third treads) treads  20  and the fastener  76  manipulated to secure the slide member  48  and the adjacent part of rail section  24  to the third lowest baluster  22  in the vertical broken line position of  FIG. 1 . These steps are repeated until all the balusters  22  for the lowermost rail section  24  are installed. 
     After a first (lowermost) rail section  24  is installed, in certain embodiments, a slide member  48  is extended into the lower end portion of a second rail section  24  and the threaded fastener  76  tightened therein to retain the slide member  48  in a position extending outwardly of second rail section  24 . The connector pins  46  are extended into channels  42   a ,  44   a  of the second rail section  24  to extend outwardly thereof. The pins  46  are of a diameter to form a tight friction fit with the rail section  24 . Now the second rail section  24 , with or without slider members  48  having balusters  22  pivotally connected thereto, is moved to have the slide member  48  and pins  46  extend into the channel  30  and channels  42   a ,  44   a , respectively, until the adjacent transverse edges of first and second rail sections  24  are in abutting relationship. As a result, the slide members  48  with balusters  22  for the second rail section  24  can be moved thereinto (if not already therein) and the lower balusters  22  for the second rail section  24  is moved lengthwise, twisted and secured to the adjacent pair of treads  20  in a manner previously indicated. 
     Additional rail sections  24 , balusters  22  and slide members  48  are interconnected to one another and the treads  20  to complete the installation of the spiral stairway  10 . To be noted is that one slide member  48  with its associated baluster  22  connected thereto may be inserted into the rail section channel  30  and slid along the rail section  24  until located in the desired position relative to the rail section  24 , and thence the baluster lower end is fixedly attached to respective tread(s)  20  and fixed to the second rail section  24  in a manner above indicated, and thence the next slide member  48  with its attached baluster  22  moved into and along the second rail section  24  for being fixed to the respective treads  20  and fixed to the rail section  24  in spaced relationship to the baluster  22  initially described as mounted. 
     Even though the installation has been described with reference to the lowermost baluster  22  being installed first, it is to be understood the installation can initially start with first installing an uppermost baluster  22 . Further, using the system of the present invention, it is also quite easy to start at a middle tread and work one&#39;s way in either direction. 
     In certain other embodiments, instead of first inserting the slide member  48  with the first baluster  22  pivotally connected thereto, the first baluster  22  may be secured to the lowermost tread  20 , then a slide member  48  is pivotally connected thereto and thereafter moved within the lowermost rail section  24  to have one of its terminal end portions adjacent to the slide member  48  and thence into the rail section channel  30  until said end is the preselected longitudinal distance from the slide member  48 . Thereafter, additional slider members  48  with balusters  22  pivotally connected thereto are inserted into the rail section  24 , if not inserted prior to the installation of the first baluster  22 , and the second slide member  48  (one adjacent to the first slide member  48 ) is longitudinal adjusted and secured in a fixed position relative to the rail section  24 . The second baluster  22  is twisted and secured to the first and second treads  20  in the manner described above. 
     It will be appreciated the embodiments of the present invention can take many forms. The true essence and spirit of these embodiments of the invention are defined in the appended claims, and it is not intended the embodiment of the invention presented herein should limit the scope thereof.

Summary:
A modular spiral staircase assembly that involves a handrail formed of one or more sections and a series of slide members each configured to form a link between both a baluster and the handrail of the staircase. The use of such slide members enables initial ease with respect to positioning of the balusters along the extent of the handrail and subsequent secure locking of such balusters in position with respect to the handrail for alignment purposes with corresponding treads of the staircase. Additionally, using such slide members along the extent of the handrail provides the installer ready-made tools for progressively shaping the extent of the handrail so as to align it with the curvature of the staircase.