Patent Publication Number: US-2011072614-A1

Title: Shower door roll wheel assembly

Description:
BACKGROUND 
     Showers generally spray water, and thus are generally enclosed via an enclosure, such as via a shower curtain or rigid shower doors. Current shower door assemblies may be problematic to install and/or produce a large amount of noise during movement. 
     SUMMARY OF THE DISCLOSURE 
     Broadly, the present disclosure relates to new shower door roll wheel assemblies, methods of coupling such assemblies to shower door mounts, and related technology. In one aspect, an apparatus includes (a) a shower door roll wheel assembly and (b) a coupling member configure to couple the shower door roll wheel assembly to a shower door mount. 
     In one approach, a shower door roll wheel assembly includes a shaft, a roll wheel, and a first (e.g., outer) flange. The roll wheel has a body having a first face, a second face, and a hub having a passageway disposed through the body. The roll wheel may be configured to rotate about an axis of the passageway. The axis of the passageway may be transverse to the first and/or second face of the body. The first face may be proximal a first end of the shaft. The second face may be proximal a second end of the shaft. The roll wheel may have a tread configured to engage a track of a shower door track. 
     The outer flange of the assembly may be coupled to the first end of the shaft. In one embodiment, the outer flange at least partially assists in restricting side-to-side movement of the roll wheel. For example, when the shower door roll wheel assembly is coupled to the coupling member and when the first flange is coupled to the first end of the shaft, the first flange and a side of the shower door mount may restrict side-to-side movement of the roll wheel. In one embodiment, the outer flange may be repeatedly coupled to and disengaged from the first end of the shaft. Thus, old roll wheels may be readily removed from the assembly, and new roll wheels may be readily installed in the assembly. 
     In one embodiment, a first portion of the roll wheel comprises a first polymeric material and a second portion of the roll wheel comprises a second polymeric material, wherein the first polymeric material is different than the second polymeric material. Due to the use of different polymeric materials, tailored properties of the roll wheel may be realized. For example, harder polymeric materials may be used where durability is a priority. Softer polymeric materials may be used where noise reduction is a priority. Self-lubricating polymeric materials may be used where low friction is a priority. In one embodiment, at least a portion of the hub of the roll wheel comprise a first polymeric material, and at least a portion of the tread of the roll wheel comprises a second polymeric material. In one embodiment, the entire hub comprises a first polymeric material. In one embodiment, the entire tread of the roll wheel comprises a second polymeric material. 
     In one embodiment, the first polymeric material is durable and/or self-lubricating. In one embodiment, the first polymeric material comprises or consists essentially of nylon. In one embodiment, the second polymeric material is soft and/or energy absorbent. In one embodiment, the second polymeric material comprises or consists essentially of urethane. In one embodiment, the first polymeric material has a shore hardness that is greater than that of the second polymeric material as measured in accordance with ASTM D2240. Shore hardness, using either the Shore A or Shore D scale, is the preferred method for rubbers/elastomers and is also commonly used for ‘softer’ plastics such as polyolefins, fluoropolymers, and urethanes. The Shore A scale may be used for ‘softer’ rubbers while the Shore D scale may be used for ‘harder’ ones. 
     In one embodiment, the roll wheel is a multi-piece roll wheel, and a first piece of the roll wheel comprises the first polymeric material, and a second piece of the roll wheel comprises the second polymeric material. In one embodiment, the first piece is a ring-shaped solid and includes at least a portion of the hub. In one embodiment, the first piece includes the entire hub. In one embodiment, at least one tab extends from an outer surface of the ring-shaped solid. In one embodiment, one or more tabs are located proximal an end portion of the ring-shaped solid. 
     In one embodiment, the second piece of the roll wheel is coupled to the first piece. In one embodiment, the second piece includes at least a portion of the tread. In one embodiment, the second piece includes the entire tread. In one embodiment, the second piece is injection molded onto the first piece. In one embodiment, the first and second pieces are integral. In one embodiment, the second piece includes at least one slot. One or more of these slots of the second piece may be configured to restrictively engage each tab of the first piece. In one embodiment, the arrangement of the tabs and/or slots facilitates a non-slip arrangement between the first piece and the second piece. For example, the tabs/slots may restrict/prevent the first piece from slipping during the rotational movement of the tread of the second piece. In one embodiment, the first face of the roll wheel comprises an extension. In one embodiment, this extension includes at least a portion of a tab of the first piece. 
     In one embodiment, the assembly includes first and second flanges. In this embodiment, the second flange may be the outer flange and the first flange may be an inner flange. The first flange may be located proximal a first end of the shaft. The first flange may be located adjacent the first (e.g., inner) face of the roll wheel. The second flange may be located proximal a second end of the shaft. The second flange may be located adjacent a second (e.g., outer) face of the roll wheel. In one embodiment, the first flange may be integral with the shaft and the second flange may be non-integral with the shaft. In one embodiment, the second flange may be configured to be coupled to or interlocked to the second end of the shaft. In one embodiment, when the roll wheel is located on the shaft and when the second flange is coupled to or interlocked to the second end of the shaft, the first flange and the second flange restrict side-to-side movement of the roll wheel. 
     The coupling member is configured to couple the shower door roll wheel assembly to the shower door mount. In one embodiment, the coupling member is configured to couple the shower door roll wheel assembly to the shower door mount via the shaft. In one embodiment, the shaft comprises one of a male fitting and female fitting, and the coupling member comprises the other of the male fitting and the female fitting. In one embodiment, the coupling member is configured to couple the shower door roll wheel assembly to the shower door mount via interconnection of the male fitting to the female fitting. In one embodiment, the male fitting and the female fitting are threaded. 
     Methods for installing shower doors are also provided. In one embodiment, a method includes the steps of (a) fixing a shaft to a shower door mount, (b) placing a roll wheel on the shaft, and (c) interlocking the roll wheel to the shaft. In one embodiment, after the interlocking step, a passageway of the roll wheel rotatably engages the shaft and side-to-side movement of the roll wheel is restricted. In one embodiment, both the placing step and the interlocking step occur before the fixing step. In one embodiment, the interlocking step includes interlocking a flange to an end of the shaft. 
     In one embodiment, the fixing step includes coupling a coupling member to at least a portion of the shaft. In one embodiment, after the coupling, a flange of the coupling member is located on a first side of the shower door mount and a flange associated with the shaft is located on a second side of the shower door mount. 
     In one embodiment, at least a portion of the roll wheel comprises urethane. In one embodiment, the method includes moving a shower door associated with the shower door mount from a first position to a second position. In one embodiment, during the moving step, the portion of the roll wheel comprising urethane absorbs energy associated with the moving step, thereby facilitating low noise emissions. In one embodiment, the low noise emissions are perceptibly less than the noise emissions of a comparable conventional nylon roll wheel. 
     Various ones of the inventive aspect, approaches, and embodiments described above may be combined to yield various shower door roll wheel assemblies, coupling members and related apparatus for installing shower doors. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1   a  is a first perspective, exploded view of an embodiment of a shower door roll wheel assembly and a coupling member in accordance with the present disclosure. 
         FIG. 1   b  is a second perspective, exploded view of the apparatus of  FIG. 1   a.    
         FIG. 2  is a cross-sectional view of the apparatus of  FIGS. 1   a  and  1   b  in partial coupled form. 
         FIG. 3   a  is a perspective view of the apparatus of  FIGS. 1   a - 1   b  connected to a shower door mount. 
         FIG. 3   b  is another perspective view of the apparatus of  FIGS. 1   a  and  1   b  connected to a shower door mount. 
         FIG. 3   c  is a side view of the apparatus of  FIGS. 1   a  and  1   b  connected to a shower door mount. 
         FIG. 4   a  is a cross-sectional, side view of a first member of the shower door roll wheel assembly of  FIGS. 1   a  and  1   b.    
         FIG. 4   b  is a perspective view of a first member of the shower door roll wheel assembly of  FIGS. 1   a  and  1   b.    
         FIG. 5   a  is a side view of the roll wheel of the shower door roll wheel assembly of  FIGS. 1   a  and  1   b.    
         FIG. 5   b  is a perspective view of the roll wheel of the shower door roll wheel assembly of  FIGS. 1   a  and  1   b.    
         FIG. 6   a  is a perspective view of one embodiment of a first piece of a two-piece roll wheel. 
         FIG. 6   b  is a perspective view of a composite roll wheel containing the first piece of  FIG. 6   a.    
         FIG. 7  is a perspective view of another embodiment of a first piece of a two-piece roll wheel. 
         FIG. 8  is an exploded, perspective view of another embodiment of a shower door roll wheel assembly and a coupling member. 
         FIG. 9  is a cross-sectional side view of the apparatus of  FIG. 8  in coupled form. 
         FIG. 10  is a perspective view of another embodiment of a shower door roll wheel. 
         FIG. 11   a  is a perspective view of another embodiment of a first member of a shower door roll wheel assembly. 
         FIG. 11   b  is a side view of an embodiment of the interconnection of the roll wheel of  FIG. 10  with the first member of  FIG. 11   a.    
         FIG. 11   c  is a perspective view of the interconnection of the roll wheel of  FIG. 10  with the first member of  FIG. 11   a.    
         FIG. 12  is a cross-sectional side view of another embodiment of an interconnection between a roll wheel and a first member. 
         FIG. 13   a  is a perspective view of another embodiment of a first member. 
         FIG. 13   b  is a side view of the embodiment of  FIG. 13   a.    
         FIG. 13   c  is a perspective view of the interconnection between a roll wheel and the first member of  FIG. 13   a.    
         FIG. 14  is a cross-sectional side view of another embodiment of an interconnection between a roll wheel and a first member. 
         FIG. 15  is a flow diagram illustrating an embodiment of method in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the accompanying drawings, which at least assist in illustrating various pertinent embodiments of the present invention. 
       FIGS. 1   a ,  1   b  and  2 , illustrate one embodiment of an apparatus of the present disclosure. In the illustrated embodiment, the apparatus includes a shower door roll wheel assembly  1  and a coupling member  80  for coupling the shower door roll wheel assembly  1  to a shower door mount  90  ( FIGS. 3   a - 3   c ). In the illustrated embodiment, the shower door roll wheel assembly  1  includes a first member  10 , a roll wheel  30 , and an outer flange member  50 . The first member includes a shaft  20 . The roll wheel  30  includes a hub portion  40  having a passageway  42 . As assembled, the roll wheel  30  rotates about the hub  40  and shaft  20 . The hub  40  may be constructed of polymeric materials, as described in further detail below. The use of such polymeric materials may facilitate energy absorption during the movement of the roll wheel  30 , and thus facilitate low or inaudible noise emissions. In one embodiment, the hub  40  is made of nylon. 
     The roll wheel  30  also includes a tread  32 . As described in further detail below, this tread  32  is configured to engage a track of a shower door track. The tread  32  of the roll wheel  30  may be made of a polymeric material, which may be the same polymeric material or a different polymeric material than that of the hub  40 . The use of a tread  32  comprising a polymeric material may facilitate energy absorption during movement of the roll wheel  30  within a track of the shower door track (e.g. due to imperfections in the track), and thus facilitate low or inaudible noise emissions. In one embodiment, the tread  32  is made of a urethane. 
     In the illustrated embodiment, the roll wheel  30  is maintained on the shaft  20  via a first flange  26  and the outer flange  50  (sometimes referred to herein as the second flange  50 ). The first flange  26 , which in this instance is integral with a first end  22  of the shaft  20 , may be located proximal (e.g., adjacent to) a first face  34  of the roll wheel  30  when the roll wheel  30  is engaged with the shaft  20 . In the illustrated embodiment, a face  54  of the second flange  50  is located proximal (e.g., adjacent to) a second face  36  of the roll wheel  30 . In one embodiment, the second flange  50  is interlocked with the second end  24  of the shaft  20  via hole  52  when the roll wheel  30  is engaged with the shaft  20 . This interlocking may be realized via flaring of the second end  24  of the shaft  20 . In other embodiments, the second flange  50  may be coupled to the second end  24  of the shaft, such as via the use of threaded members (e.g., a screw-nut arrangement). Thus as assembled, the first and second flanges  26 ,  50  may restrict the side-to-side movement of the roll wheel  30  as engaged with the shaft  20 . In some embodiments, the second flange  50  may be repeatedly interlocked to (or coupled to) and disengaged from the second end  24  of the shaft  20  so as to facilitate repeated assembly and disassembly of the shower door roll wheel assembly  1 . 
     Interlocked means to connect together so that the individual parts affect each other in motion or operation. In some embodiments, interlocked elements are incapable of any substantial movement relative to each other. Couple and the like means to connect. In some embodiments, one object may be coupled to another object, but not in an interlocked fashion. In other embodiments, one object may be coupled to another object, and in an interlocked fashion. Adjacent means near or close to, but not necessarily in contact. In some embodiments, a first object may be adjacent a second object, but not touching the second object. In other embodiments, the first object may be adjacent the second object, and at least partially touching the second object. 
     Referring now to  FIGS. 1   a ,  1   b ,  2 , and  3 , the coupling member  80  is configured to couple the shower door roll wheel assembly  1  to a shower door mount  90 . In the illustrated embodiment, the shower door mount  90  includes a slanted window  92  for facilitating interconnection of the coupling member  80  to the shower door roll wheel assembly. As coupled, a flange (e.g., screw head) of the coupling member  80  may engage a first side of the shower door mount  90 , and a flange of the shower door roll wheel assembly  1  may engage a second side of the shower door mount. Thus, the shower door roll wheel assembly  1  may be coupled (e.g., fixed) to the shower door mount  90  via the coupling member  80 , and at the desired vertical position within the slanted window  92 . In other embodiments, the first flange  26  is absent and the fixing of the assembly  1  to the mount  90  is accomplished by configuring the coupling between the assembly  1  and the coupling member  80  in an appropriate manner. For example, the length of the coupling member  80  may be tailored to facilitate fixing of the assembly  1  to the mount  90 . 
     The shower door mount (also known as a shower door bracket) may also include a door holding portion  94  for receiving and/or holding a shower door. The shower door mount  90  may be adapted to both (i) restrictively engage at least a portion of a shower door, and (ii) place at least one roll wheel of a shower door roll wheel assembly in contact with a shower door track. In this manner, as the roll wheel moves from a first position to a second position along the shower door track, the shower door may be positioned from a first position to a second position due to, at least in part, its restrictive engagement with the shower door mount. 
     A shower is any system having a sprayer for spraying a liquid (e.g., water). A shower may include an enclosure adapted to facilitate containment of sprayed liquid. A shower enclosure may include a shower door assembly. A shower door assembly is an assembly of material configured to facilitate movement of at least one shower door from a first position (e.g., a generally open position) to a second position (e.g., a generally closed position). A shower door assembly may include a shower door, a shower door mount, and a shower door track. A shower door is any material that is suitable for use as a door in a shower. In one embodiment, a shower door is a generally solid piece of material, such as glass (e.g., glass that is translucent, transparent, colored, or otherwise). A shower door track (not illustrated) is a material adapted to engage a tread  32  of a roll wheel  30  of a shower door roll wheel assembly  1 , and with the purpose of allowing the roll wheel  30  to move along at least a portion of the length of the shower door track. In one embodiment, the shower door track includes at least one groove for engaging a tread  32  of a roll wheel  30  of a shower door roll wheel assembly  1 . A shower door roll wheel assembly is an assembly having at least one roll wheel, and which is configured to facilitate movement of a shower door from a first position to a second position, such as from a generally open position to a generally closed position. For example, a shower door roll wheel assembly may be in at least partially contact with one or more of (i) a shower door mount and (ii) a shower door track, as described above. 
     In the illustrated embodiment, the first member  10  of the shower door roll wheel assembly  1  includes a female portion  28  configured to engage a male portion  82  of the coupling member  80 . In the illustrated embodiment, both the male portion  82  and the female portion  28  include threads for facilitating the coupling of the shower door roll wheel assembly  1  to the shower door mount  90  via the coupling member  80 . Other coupling arrangements may be utilized. 
     In some embodiments, the hub  40  of the roll wheel  30  and the shaft  20  are rotatably engaged. The hub  40  and the roll wheel  30  are rotatably engaged when the clearance between the outer surface of the shaft  20  and the inner surface of the hub  40  is large enough such that the roll wheel  30  can readily rotate about its rotation axis, but the clearance between the outer surface of the shaft  20  and the inner surface of the hub  40  is small enough such that the long axis  44  ( FIG. 5   a ) of the roll wheel  30  generally maintains its position. Generally, the clearance should be sufficiently small so as to prevent wobble of the roll wheel, while also allowing ready rotation of the roll wheel about the shaft. In some embodiments, the clearance is not greater than 0.010 or 0.005 inch. 
     In the illustrated embodiment, only a single door mount  90  and a single window  92  are illustrated. However, the mount  90  may have multiple windows, each window  92  having an assembly  1  coupled thereto via coupling member  80 . For example, a mount  90  may be sized to be coincidental to the size of a shower door. In this embodiment, the mount  90  may have at least two windows  92 , with one window  92  and assembly  1  located proximal each end of the mount  90 . The mount may also have one or more additional windows  92  and assemblies  1  located in the middle portions of the mount  90 . The use of multiple windows  92  and assemblies  1  within a single mount  90  may assist in the movement of and/or the support of the shower door, which may be relatively heavy in some circumstances. In other embodiments, multiple mounts  90  may also be used for a single enclosure for mounting one or more shower doors. 
     Referring now to  FIGS. 1   a ,  1   b ,  2 ,  4   a  and  4   b , the first member  10  generally includes a shaft  20  having a first end  22  and a second end  24 . A member means a part of a group. In the illustrated embodiment, the first member  10  is part of the group forming the illustrated apparatus. In the illustrated embodiment, a first flange  26  is located proximal the first end  22  of the shaft  20 . In the illustrated embodiment, the first flange  26  is integral with the shaft  20 . In this instance, integral is similar to integrated and means formed into or united as a whole. In other embodiments, the first flange  26  may be non-integral with the shaft  20 , and may be merely coupled to or interlocked to the first end  22  of the shaft  20 . A flange is a protruding rim, edge, rib, collar, or other protrusion used to strengthen an object, hold it in place, or attach it to another object, among other things. 
     In the illustrated embodiment, the second end  24  of the shaft  20  is configured to interlock the second flange  50  to the shaft  20 . In this regard, the second end  24  may include a tapered surface, as illustrated, or other suitable features to facilitate the interlocking of the second end  24  and the second flange  50 . For example, after placement of the second flange  50  on the second end  24  of the shaft  20 , the second end  24  may be mechanically deformed to interlock the second flange  50  on the second end  24 . In other embodiments, the second end  24  and/or second flange  50  may include features that merely allow coupling of the second flange  50  to the shaft  20 . In yet other embodiments, the second flange  50  may be integral with the shaft  20 . In some embodiments, at least one of the first and second flanges  26 ,  50  is non-integral with the shaft  20 . In other embodiments, both of the first and second flanges  26 ,  50  are integral with the shaft  20 . 
     The arrangement of the first and second flanges  26 ,  50  may be such that side-to-side movement of the roll wheel is restricted. To restrict side-to-side movement of the roll wheel means that one or more flanges are located sufficiently proximal one or more faces of the roll wheel such that the long axis  44  of the roll wheel realizes restricted lateral movement while also enabling the roll wheel to readily rotate about a rotation axis. Close proximity between the flange(s) with limited physical contact between the flange(s) and the roll wheel may facilitate restricted side-to-side movement of the roll wheel. In one embodiment, two flanges are located next to two corresponding side faces of the roll wheel, and each flange is located about 0.005 to about 0.010 inch from its corresponding face of the roll wheel. In another embodiment, only an outer flange  50  is used, and the fixing of the assembly  1  to the mount  90  is accomplished by configuring the coupling between the assembly  1  and the coupling member  80  in an appropriate manner. For example, the length of the coupling member  80  may be tailored to facilitate fixing of the assembly  1  to the mount  90 . 
     The shaft  20  is a rod or rod-like structure. The material of the shaft  20  should facilitate rotatable engagement of the hub  40  of the roll wheel  30 , while also maintaining the durability of the shaft  20  and the hub  40  of the roll wheel  30 . The shaft should have a smooth outer surface so as to facilitate rotation of the roll wheel. In one embodiment, the shaft  20  comprises or consists essentially of a metal material, such as stainless steel, zinc-plated steel, brass, and aluminum, among others. The first flange  26  may be produced from the same or similar material as the shaft  20 . When the first flange and the shaft  20  are integral, they comprise the same material. 
     The first member  10  may include a male or female portion  28  for facilitating interconnection of the shower door roll wheel assembly  1  and the coupling member  80 . The coupling member  80  may have the other of a male or female portion relative to the first member  10 . In the illustrated embodiment, the first member includes a female portion  28  having threads  29 . In the illustrated embodiment, the coupling member  80  has a male portion  82  having corresponding threads  84 . In the illustrated embodiment, the female portion  28  is in the form of a passageway that extends completely through the body of the shaft  20  (e.g., all the way through the first end  22  and the second end  24  of the shaft  20 ). In the illustrated embodiment, the threads  29  extend only partially along the passageway, but in other embodiments the threads  29  may extend the entire length of the passageway. The passageway may have a center axis  27 , which may be concentric with an axis  42  of the hub  40  of the roll wheel ( FIGS. 5   a ,  5   b ). 
     In other embodiments, the female portion  28  may be in the form of a partial passageway that does not extend all the way through the body of the shaft  20  (e.g., from the first end  22  to a middle portion of the shaft  20 ). In such embodiments, the threads  29 , or other suitable coupling/interlocking mechanism, may extend partially or completely through the partial passageway. Other coupling configurations may be utilized. 
     The first member  10  may include a projection  23 . The projection  23  may be configured to restrictively engage the window  92  of the shower door mount  90  ( FIGS. 3   a - 3   c ). This restrictive engagement may allow the apparatus to slide laterally along the window but restrict, and in some instances prevent, rotational movement of the shaft of shower door roll wheel assembly. In the illustrated embodiment, the projection  23  is integral with one of the first flange  26  and the shaft  20 . In other embodiments, the projection  23  may be non-integral with the first flange  26  and/or the shaft  20 . 
     Referring now to  FIGS. 1   a ,  1   b ,  2 ,  5   a , and  5   b , the shower door roll wheel assembly generally includes a roll wheel  30 . A roll wheel is a device adapted to facilitate rotational movement. In one embodiment, at least a portion of the roll wheel  30  is produced from a polymeric material, such as urethane, nylon, vinyl, PVC, elastomer materials, and the like, as described in further detail below. The use of such polymeric materials, especially urethane, may facilitate low noise emissions by the shower door roll wheel assembly during movement of the roll wheel  30 . Furthermore, polymeric materials are generally inert to water-containing atmospheres. 
     In the illustrated embodiment, the roll wheel  30  is a body having a tread  32 , a first face  34 , a second face  36  (which is opposite the first face  34 ), and a hub  40 . Body and the like means an object having a distinguishable mass. The tread  32  of the roll wheel  30  is configured to engage a track of a shower door track (described above). The tread  32  of the roll wheel  30  may be made of a polymeric material. The use of a polymeric material as the tread may facilitate energy absorption during the movement of the roll wheel  30  within the track of the shower door track (e.g. due to imperfections in the track), and thus facilitate low or inaudible noise emissions. In one embodiment, a tread  32  of the roll wheel  30  is sufficiently soft so as to facilitate noise reduction of a shower roll wheel assembly  1 . In some embodiments, the tread  32  of the roll wheel  30  may have a tailored shore hardness as measured in accordance with ASTM D2240. In one embodiment, the tread has a Shore A scale hardness in the range of 40 to 95. In one embodiment, the tread has a Shore A scale hardness in the range of 60-95. In one embodiment, the tread has a Shore D scale hardness in the range of 40-90. In one embodiment, the tread has a Shore D scale hardness in the range of 40 to 60. In one embodiment, the tread is a urethane and has a Shore A scale hardness of about 90. In one embodiment, the tread is a urethane and has a Shore D scale hardness of about 50. Polymeric materials suited for use as the tread include urethanes, elastomers, silicones, vinyls and similar materials. Urethanes include those materials produced from polyurethane resins of ethyl carbamate, which has a chemical formula of CO(NH 2 )C 2 H 5 . In one embodiment, the urethane is polyurethane, which is a thermoplastic polymer that may be produced by the condensation reaction of polyisocyanate and a hydroxyl-containing materials (e.g., a polyol derived from propylene oxide or trichlorobutylene oxide). The basic polymer unit of a polyurethane is formed as follows: R 1 NCO+R 2 OH→R 1 NHCOOR 2 . In one embodiment, the tread  32  comprises or consists essentially of urethane. 
     The roll wheel  30  generally includes a hub  40  having a passageway disposed through the body of the roll wheel  30 . The hub  40  is generally configured to rotatably engage a shaft  20  of the shower door roll wheel assembly  1 . The hub  40  generally includes an axis  42 , which is generally the rotation axis of the roll wheel  30 . The axis  42  may be concentric with an axis of the shaft  20 . The hub axis  42  is generally transverse to the first and second faces  34 ,  36  of the roll wheel  30 . A long axis  44  of the roll wheel  30  is generally transverse to the hub axis  42 . In some embodiments, the long axis  44  may be parallel to at least one face  34 ,  36  of the roll wheel  30 . In some embodiments, the long axis  44  may intersect at or near the center of the width W of the roll wheel  30 . 
     Hub means the central part of a wheel through which a shaft or axle passes. A hub generally has a passageway. Passageway and the like means a path through or along which something may pass. Axis and the like means a straight line through an object. In some embodiments, an axis may be a rotational axis about which a body or geometric object rotates or may be conceived to rotate. Rotate and the like means to turn on an axis. Transverse and the like means non-parallel. Face and the like means a portion of an outer surface of an object. 
     In one embodiment, at least a portion of the hub  40  of the roll wheel is made up of a polymeric material. The polymeric material of the hub  40  may be the same or different than the polymeric material of the tread  32 . Polymeric materials useful relative to the hub  40  include those materials that facilitate rotational movement of the hub  40  of the roll wheel  30  about the shaft  20 , but with restricted and/or no degradation of the shaft  20  and/or the hub  40  of the roll wheel  30 . It is also useful if the material is naturally lubricating so as to facilitate rotational movement. Polymeric materials suited for this purpose include NYLON, TEFLON, DELRIN, UHMW polyethylenes, polypropylene, and related materials. In one embodiment, at least a portion of the hub  40  comprises or consists essentially of nylon. Nylon means any of a family of synthetic polymers that include the recurring amide group —CONH. Suitable nylon materials for use as the hub include Nylon 66 and Nylon 6, among others. In one embodiment, the hub  40  comprises or consists essentially of a nylon material. 
     The above-described roll wheel  30  has generally been illustrated as a unitary body. However, in other embodiments the roll wheel  30  may comprise a plurality of pieces. One embodiment of a multi-piece roll wheel is illustrated in  FIGS. 6   a  and  6   b . In this embodiment, the roll wheel  130  comprises a ring-shaped first piece  150  and a second piece  170 . The ring-shaped first piece  150  comprises a hub  140  having a passageway and an axis  142 . The first piece also comprises the inner surface  146  of the hub  140 , which is designed to rotatably engage a shaft, as described above. The ring-shaped first piece  150  includes an outer surface  154  having a one or more tabs  156  disposed thereon. In the illustrated embodiment, each of the tabs  156  are located near one of the ends of the ring-shaped first piece  150 . In other embodiments, one or more tabs  156  may be located away from the ends of the ring-shaped first piece  150 . The tabs  156  are also offset from one another, which may facilitate a non-slip arrangement. The second piece  170  may include a plurality of slots that restrictively engage the tabs  156 . Thus, as the roll wheel  130  rotates, little or no slip between the first and second pieces  150 ,  170  will occur. For example, due to the arrangement of the one or more tabs  156 , when a force is placed on the shower door mount (e.g., to move shower door), direct or near-direct translation of energy from the tread to the hub may occur, which may result in low noise emissions, restricted side-to-side movement of the roll wheel, and/or rotatable engagement of the shaft and the hub. 
     In the illustrated embodiment, the first face includes an extension  157  having some of the tabs  156 . This extension  157  may act as a bumper between a flange and/or a side of a shower door mount so as to facilitate restricted side-to-side movement of the roll wheel. 
     The ring-shaped first piece  150  may be made from a first polymeric material, such as nylon, so as, for example, to facilitate durable construction for use in conjunction with rotatable engagement with a shaft. The second piece  170  may comprise a second polymeric material, such as urethane, which may be injection molded onto the first piece  150 , to produce the multi-piece roll wheel  130 . The urethane may facilitate low noise emissions of the assembly. Thus, the materials of the multi-piece roll wheel may be tailored to achieve the desired functionality. For example, durability may be tailored via use of nylon and sound emissions may be tailored via use of urethane. The first piece  150  may be considered a plastic bushing that is durable and helps to absorb noise created due to the movement of the roll wheel  130 . The first piece  150  may be considered an integral bearing as part of a substructure of the roll wheel  130 , creating a precision concentric roller. The use of a separate first piece  150  may facilitate precision in creating a concentric arrangement between the axis of the hub and the axis of the shaft. The hub of the first piece may act as a bearing surface, reducing or eliminating friction and tolerance issues associated with other multi-piece systems. In the illustrated embodiment of  FIG. 6   b , the first and second pieces are integral (e.g., due to the injection molding of the second piece onto the first piece; due to the use of adhesive). 
     Another embodiment of a first piece of a multi-piece roll wheel is illustrated in  FIG. 7 . In the illustrated embodiment, the ring-shaped first piece  150  comprises a hub  140  having a passageway, the axis  142  and the inner surface  146  of the hub  140 , as described above. The ring-shaped first piece  150  also comprises the above-described tabs  156 , but also includes one or more connection members  158 , which are located on the outer surface  154  of the ring-shaped first piece  150  and at least partially connect one tab to one or more other tabs. In the illustrated embodiment, the connection members  158  extend across the outer surface  154  of the first piece  150 , and connect tabs  156  located on a first end to tabs  156  located on a second end of the ring-shaped first piece  150 . 
     Another embodiment of a multi-piece roll wheel assembly is illustrated in  FIGS. 8 and 9 . In the illustrated embodiment, the apparatus includes a shower door roll wheel assembly  201  and a coupling member  80 . The shower door roll wheel assembly  201  includes a first member  210  having a flanged second end  224  for interlocking with a second flange  50 . The shower door roll wheel assembly  201  also includes a roll wheel  230  having a first piece  250  and a second piece  240 . The second piece  240  comprises the tread and first face of the roll wheel  230 . The second piece  240  may be made from a first polymeric material, such as urethane. The first piece  250  of the roll wheel  230  comprises a hub  254  having a passageway  252  and a portion of the second face of the roll wheel  230 . The first piece  250  may be made from a second polymeric material, such as nylon. The second piece  240  includes a recess  242  for receiving at least a portion of the first piece  250  such as the hub  254  of the first piece  250 . The first piece  250  may also include a flange  256  for restrictively engaging the end of the indent  242 , thereby positioning the first piece  250  with in the second piece  240 . In the illustrated embodiment of  FIG. 8 , the first and second pieces  240 ,  250  are non-integral. 
     Another embodiment of a roll wheel is illustrated in  FIG. 10 . In the illustrated embodiment, the roll wheel  330  includes a hub  333  having a passageway  340  for rotatably engaging a shaft. The roll wheel  330  also includes a plurality of apertures  331  extending through the body of the roll wheel  330 . These apertures  331  may facilitate low noise emissions by dampening the effects of air movement that may occur during rotation of the roll wheel  330 . In the illustrated embodiment, the apertures  331  extend completely through the body of the roll wheel  330 . However, in other embodiments, the apertures  331  may only extend partially through the body of the roll wheel  330 . Also, while a plurality of apertures  331  are illustrated, only a single aperture may be utilized in some instances. 
     Another embodiment of a roll wheel-shaft arrangement is illustrated in  FIGS. 11   a  through  11   c . In the illustrated embodiment, a first piece  310  includes a first flange  326  and a second flange  350 . In the illustrated embodiment, the first and second flanges  326 ,  350  are integral with the shaft  320 . In other embodiments, at least one of the first and second flanges  326 ,  350  may be non-integral with the shaft. The first piece  310  also includes a shaft  320  for rotatably engaging a hub of a roll wheel, such as the hub  333  of roll wheel  330  of  FIG. 10 . The first and second flanges  326 ,  350  may restrict side-to-side movement of the roll wheel  330 . In the illustrated embodiment, the shaft  320  includes a male member  360 , which may engage a female portion of a coupling member, so as to couple the assembly to a shower door mount. 
       FIG. 12  illustrates an embodiment similar to the embodiment illustrated in  FIGS. 11   a  through  11   c  but with a multi-piece roll wheel. In this embodiment, the roll wheel  330  includes a first piece  335  and a second piece  332 . The first piece  335  may be made from a first polymeric material, and the second piece  332  may be made from a second polymeric material. In this regard, the first piece  335  may be considered an integral bearing molded as part of the substructure of the roll wheel  330  creating a precision concentric roller. A center hub (e.g., hub  333  of  FIG. 10 ) may also act as a bearing surface, which reduces friction and tolerances when having multiple items fitting together. 
     Another embodiment of a roll wheel assembly is illustrated in  FIGS. 13   a  through  13   c . In the illustrated embodiment, the assembly includes a roll wheel  430  having a hub, similar to  FIG. 10 , described above. The first member  410  includes a shaft  420  and a first flange  426 . The first member  410  also includes a threaded male coupling member  460  for coupling with a threaded female coupling member, so as to couple the assembly to a shower door mount. The first member  410  also includes indents for facilitating coupling of the first member  410  to the threaded female coupling member. 
     The roll wheel  430  may also be made of multiple pieces, as illustrated in  FIG. 14 . In the illustrated embodiment, the roll wheel  430  includes a first piece  435  and a second piece  433 . As described above, the first piece  435  may be made of a first polymeric material and the second piece  433  may be made from a second polymeric material. As described above, this facilitates tailored polymeric properties for the hub portion and the tread portion of the roll wheel  430 . 
     Methods relating to the installation of shower doors utilizing the inventive shower door roll wheel assembly are also provided, one embodiment of which is illustrated in  FIG. 15 . In the illustrated embodiment, the method includes the steps of fixing a shaft to a shower door mount  1510 , placing a roll wheel on the shaft  1520 , and coupling or interlocking the roll wheel to the shaft  1530 . In one embodiment, the placing step  1520  occurs before the fixing step  1510 . In another embodiment, the placing step  1520  occurs after or concomitant to the fixing step  1510 . In one embodiment, the coupling or interlocking step  1530  occurs before the fixing step  1510 . In one embodiment, the coupling or interlocking step  1530  occurs after or concomitant to the fixing step  1510 . Due to the flexibility of the installation steps of the shower door roll wheel assembly, shower door installation may be readily accomplished. 
     In one embodiment, the fixing step  1510  includes coupling a coupling member  1512  to at least a portion of the shaft. In this regard, after this coupling step, a flange of the coupling member may be located on one side of the shower door mount, and a flange associated with the shaft may be located on a second side of the shower door mount, thus achieving the fixing of the shaft to the shower door mount. In one embodiment, this coupling step includes inserting a threaded male member into a threaded female member  1515 . In this regard, the coupling member  1512  may include one of the threaded male member and the threaded female member  1514 , and the shaft may include the other of the threaded male member and the threaded female member  1514 . In other embodiments, the coupling may be accomplished via other known arrangements, such as a tab and clip arrangement  1516 , among others. 
     As described above, a roll wheel may be placed on a shaft  1520 . In one embodiment, the roll wheel and shaft are configured such that the roll wheel rotatably engages the shaft  1520  concomitant to the placing step. 
     As described above, the method may include the step of coupling or interlocking the roll wheel to the shaft  1530 . Concomitant to this coupling or interlocking step  1530 , the side-to-side movement of the roll wheel may be restricted  1532 . In one embodiment, the coupling or interlocking is accomplished via one or more flanges  1533 , such as via any of the above-described flanges. 
     In some embodiments, the assembly may facilitate replacement of roll wheels. In this regard, a method may include the step of replacing a roll wheel  1534 . This replacing roll wheel step  1534  may include the step of removing the flange  1535 , removing the roll wheel from the shaft  1536 , and placing a new roll wheel on the shaft  1537 . The method may also include coupling or interlocking a flange  1538  to the shaft to restrict the side-to-side movement of the new roll wheel. In this regard, the flange may be the originally used flange that was used to couple or interlock the old roll wheel to the shaft, or may be a new flange. 
     The method may also include the step of moving the shower door from a first position to a second position  1540 . In this regard, when the roll wheel comprises at least some soft polymeric material (such as urethane), during the moving step  1540 , the portion of the roll wheel that comprises soft polymeric material may absorb energy associated with this moving step  1540 , thereby facilitating low noise emissions. In one embodiment, the low noise emissions are perceptibly less than noise emissions of a comparable conventional nylon roll wheel. 
     While various embodiments of the present invention have been described in detail, it is apparent that modifications and adaptations of those embodiments will occur to those skilled in the art. For example, a precision roller bearing system, such as those used in in-line skates, could be used in the shower door roll wheel assembly of the present disclosure. This modification, and all other such modifications and adaptations, are within the spirit and scope of the present invention.