BACKGROUND OF THE INVENTION 
     This invention pertains to partition wall systems and, more particularly, to an engagement assembly that couples a wall panel to the ceiling without piercing the ceiling itself. The engagement assembly may also provide a sound and light attenuation barrier. The present invention is believed to be particularly applicable for wall systems located in areas prone to measurable seismic events. 
     Increasingly, interconnected modular wall systems are being used to define offices, conference rooms, storage rooms, and workrooms. The wall systems are not designed to be load bearing. As such, they can be fastened to the floor and the suspended ceiling of a building at nearly any location. As the needs for the office space change, such as with a new tenant, the wall systems can be rearranged or replaced, as needed, without affecting the structural integrity of the building. An exemplary modular wall system is the Genius wall system, commercially available from Krueger International, Inc. of Green Bay, Wis. 
     New seismic regulations require that a suspended ceiling be able to sway like a pendulum a predetermined distance, e.g. one inch, in all directions in response to a seismic event. This can be particularly problematic for wall panels that are attached, using fasteners or similar connectors, directly to the suspended ceiling. Moreover, code requirements demand that the wall panels be able to withstand the impact of a seismic event. This has led to the design of sturdier wall panels. While having an improved response to seismic events, the seal between the suspending ceiling and the wall panel can be susceptible to sound and/or light transference. This has led to the need for a series of braces above the ceiling (called kicker braces) that support the walls that can be expensive and time consuming to install. The kicker braces attach to the top of the wall and to the building structure above the ceiling at 45 degrees every four feet. The penetration through the suspended ceiling has to be large enough for the brace plus one inch clearance around the brace to allow the ceiling to sway unobstructed. This penetration can be wider than the width of the wall, which can compromise the effectiveness of the wall system. 
     Thus, there is a need in the art for a modular wall system for use in seismic active areas that is compliant with seismic-related building codes, but also provides noise and light abatement that does not penetrate the ceiling. 
     BRIEF DESCRIPTION OF THE INVENTION 
     This disclosure is directed to a modular wall system used in a space dividing system, such as an office space configuration system, suitable for seismic active areas. The system includes a partition wall or wall panel designed to extend between the floor of the office interior and the ceiling. The partition wall is held stationary in this position without any fasteners, braces or other securing members that penetrate into the ceiling. To hold the partition wall in position against the ceiling, the wall includes a pair of wall extensions secured to opposite sides of the wall and that contain a sound attenuating material, such as a foam material or fiberglass therebetween. 
     Therefore, in accordance with one aspect of the present invention, an apparatus for retaining a wall panel to a ceiling surface is presented. The apparatus includes a pair of wall extensions adapted to abut against the ceiling surface and a guide that retains the wall extensions, and which carries a shank. The apparatus further includes a spacer coupled to the shank and adapted to snugly retain the wall extensions against the wall panel. The height of the wall panel relative to the spacer is defined by the position of the spacer relative to the shank. 
     In accordance with another aspect, the present invention is directed to a wall system adapted for use in regions with seismic building criteria. The wall system includes a wall panel and a spacer connected to the wall panel. The wall system further includes a wall extension member adapted to abut a ceiling and further adapted to adjustably retain the spacer at one of a plurality of heights. 
     According to another aspect, the present invention is directed to an apparatus for extending the height of a wall panel to traverse a distance between a floor surface supporting the wall panel and a ceiling surface. The apparatus includes a pair of wall extensions adapted to snugly fit against respective exterior wall surfaces of the wall panel. A guide removably retains the pair of extensions and carries a threaded spacer that threadedly receives a bolt adapted to carry the wall panel. The height of the wall extensions relative to the wall panel is set by the position of the bolt on the threaded spacer, such that the extensions can be positioned against the ceiling surface. 
     Various other features, objects and advantages of the present invention will be made apparent from the following detailed description and the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings illustrate one preferred embodiment presently contemplated for carrying out the invention. 
       In the drawings: 
         FIG. 1  is a partial isometric view of a modular wall system in which the upper end of the panels of the wall system are adapted to engage the ceiling of a space within a building using the wall panel-ceiling engagement assembly according to the present invention; 
         FIG. 2  is a partial, enlarged exploded isometric view of the wall panel-ceiling engagement assembly incorporated in the modular wall system of  FIG. 1 ; 
         FIG. 3  is an exploded isometric view of a guide forming a part of the wall panel-ceiling engagement assembly of  FIG. 2 ; 
         FIG. 4  is a section view of the modular wall system taken along lines  4 - 4  of  FIG. 1 ; 
         FIG. 5  is a section view similar to that of  FIG. 4  showing the wall panel-ceiling engagement assembly being retained at an elevation greater than that shown in  FIG. 4 ; 
         FIG. 6  is a section view similar to that of  FIGS. 4 and 5  showing the wall panel-ceiling engagement device being retained at an elevation greater than shown in both  FIGS. 4 and 5 ; and 
         FIG. 7  is an isometric view of a corner brace used to join adjacent panels. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a portion of a modular wall system  10  composed of a pair of wall panels (or partition walls)  12  connected to one another by a corner brace  14 . A corner cover  15  extends from the corner brace  14  and runs the height of the pair of wall panels  12  and assists in connecting the adjacent wall panels  12  to one another. As will be described with respect to  FIG. 7 , the corner brace  14  allows the joined wall panels to swing as a single structure during seismic events. The wall panels  12  are designed to abut the underside of a suspended ceiling (not shown) via a slip joint connection, which will be explained. As will also be explained in greater detail below, the wall panels  12  are constructed to be shorter than the distance between the suspended ceiling and a floor, shown at  16 . The gap between each wall panel  12  and the ceiling is traversed by a pair of wall extensions  18 ,  20  designed to abut against the underside of the suspended ceiling and be retained thereagainst without the use of a fastener or similar device penetrating through the ceiling. A channel  22  is defined between the wall extensions  18 ,  20  which, in a preferred embodiment, is filled with light and sound abatement material, such as foam or insulation. In addition, a wall panel-ceiling engagement device or assembly  24  is retained within the channel  22  and, as will be described, receives the wall extensions  18 ,  20  in a manner that allows the height of the wall extensions  18 ,  20  relative to the wall panel  12  to be adjusted. 
     Wall system  10  may be generally constructed as shown and described in U.S. Pat. No. 6,688,056 granted Feb. 10, 2004, the disclosure of which is hereby incorporated by reference. It is understood, however, that wall system  10  may have any other desired construction. With additional reference to  FIG. 2 , each section of wall panel  12  includes an upper frame member  26 . The upper frame member  26  has a lower surface  28  interconnected between a pair of sidewalls  30 ,  32  having inwardly projecting flanges  34 ,  36 , respectively. Flanges  34 ,  36  are engaged with and received by the wall panel-ceiling engagement device  24 , in a manner to be explained, so as to couple the wall panel  12  to the wall panel-ceiling engagement device  24 . Alternately, sheet metal screws or similar fasteners may be used. 
     As also shown in  FIG. 2 , wall extensions  18 ,  20  are designed to abut exteriorly of sidewalls  30 ,  32 , respectively, of upper frame member  26 . Each wall extension  18 ,  20  is constructed to have a lip  38 ,  40 , respectively, that is designed to abut against the underside of a ceiling, which representatively may be a suspended ceiling. Additionally, wall extensions  18 ,  20  have respective inwardly extending arms  42 ,  44 . Arms  42 ,  44  are designed to be retained by the wall panel-ceiling engagement device  24 , thereby coupling the wall extensions  18 ,  20  to the wall panel-ceiling engagement device  24 . 
     More particularly and with additional reference to  FIG. 3 , wall panel-ceiling engagement device  24  has a guide  46  composed of a pair of top guide plates  48  connected to a bottom guide plate  50  in a manner such that a gap  52  is formed therebetween. Gap  52  forms a receptacle or space for receiving arms  42 ,  44  of the wall extensions  18 ,  20 . A stud or bolt  54  extends downwardly from guide  46  and is constructed to receive a spacer  56 . 
     In the illustrated embodiment, the top guide plates  48  and the bottom guide plate  50  are in the form of extruded members formed of a material such as aluminum or steel, although it is understood that any other satisfactory material and forming method may be employed. Top guide plates  48  and bottom guide plate  50  include mating connection structure that enables guide plates  48 ,  50  to be connected together. As shown in  FIG. 3 , the mating connection structure may be in the form of a pair of upwardly facing T-connectors  53  formed on lower guide member  50 , each of which is adapted to fit within a respective channel  55  formed on upper guide plates  48 . Alternatively, the mating connection structure may be in the form of facing channels formed on lower guide plates, which receive T-shaped connectors formed on the upper guide plate. 
     As shown in  FIGS. 3 and 4 , spacer  56  includes a pair of spacer plates  58 ,  60  separated from one another by a center plate  62 . A grommet  64  has a barrel  66  that extends centrally through plates  58 - 62 , and includes an interior wall  68  having threads that engage threads  70  of the bolt  54  when the spacer  56  is threaded onto bolt  54  or bolt  54  is threaded into grommet  64 . It is contemplated that the spacer  56  may be threaded onto bolt  54  with the grommet  64  facing downward or with the grommet facing upward, with both positions being illustrated in  FIG. 3 . 
     Center plate  62  is angularly offset from plates  58 ,  60  thereby forming a channel between plates  58 ,  60  that is adapted to receive flanges  34 ,  36 . Center plate  62  has a width that matches the distance between the facing edges of flanges  34 ,  36 . As shown in  FIG. 4 , flanges  34 ,  36  are received in the channel and abut the lateral edges of center plate  62 . In one preferred embodiment, screws or rivets  72  fixedly attach flanges  34 ,  36  to plates  58 ,  60 . Thus, the wall panel  12  is attached to spacer  56  by upper frame member  26 . It is noted that that wall panel  12  is also fixedly coupled to the upper frame member  26  by a channel and lock assembly  74 , as known in the art. Alternately, spacer  56  may be screwed directly to the upper frame member  26 . 
     Still referring to  FIG. 4 , wall panel-ceiling engagement device  24  further includes a spacing bolt  76  coupled to guide  46  by a retention pin  78 . Spacing bolt  76  defines a minimum distance between spacer plate  58  and guide  46 . That is, spacing bolt  76  is operative as a stop for the spacer  56  thereby providing a rotational limitation for the spacer when being threaded to bolt  54 . In one embodiment, spacing bolt  76  is coupled to a retention rivet  78 . More particularly, the head of the bolt  76  has a clearance hole extending at least partially therethrough. Rivet  78  passes through the clearance hole in aluminum extrusion and into the hole in the head of the bolt  76 . This allows the spacer to be adjusted up and down without spinning around. That is, a user can clip one wall extension onto one side, adjust the bolt until the wall extension makes contact with the ceiling, install noise and/or light abatement material if desired, and clip on the other wall extension knowing that the spacer is properly adjusted. 
     Wall extensions  18 ,  20 , flanges  34 ,  36 , spacer plate  58 , and ceiling  80  collectively form a cavity  82  that, in one preferred embodiment, is filled with sound and light abatement material  84 . In one embodiment, the sound and light abatement material is insulating foam or fiberglass, but is recognized that other sound and light abatement materials may be used. It is also contemplated that the sound and light abatement materials may also be deposited in the space formed between spacer  56  and the bottom surface  28  of the upper frame member  26 . 
     As noted above, guide  46  is constructed to form a gap  52  adapted to receive arms  42 ,  44  of wall extensions  18 ,  20 , respectively. As shown in  FIG. 4 , arms  42 ,  44  have rounded ends  86 ,  88 , respectively, that rest within grooves  90 ,  92 , respectively, formed in the lower guide plate  50 . When the arms  42 ,  44  are fully inserted, rounded ends  86 ,  88  sit in grooves  90 ,  92 , respectively, and top guide plates  48  exert a downward bias on arms  42 ,  44 , that forcibly engage arms  42 ,  44  with lower guide plate  50 . In this manner, the arms  42 ,  44 , and thus the wall extensions  18 ,  20 , are securely coupled to guide  46 . Moreover, the top guide plate  48  pressing down on the arms  42 ,  44  causes the wall panel-ceiling engagement device  24  to rotate down sealing against the wall panel  12 . 
     The height of the wall extensions  18 ,  20  relative to the wall panel  12  is determined by the position of spacer  56  on bolt  54 . For instance,  FIGS. 4 and 5  show two possible positions of the wall extensions  18 ,  20  relative to the wall panel  12 . In  FIG. 4 , the wall extensions  18 ,  20  are closer to the top of the wall panel  12  than in  FIG. 5 . This is a result of spacer  56  being threaded higher up on bolt  54  in  FIG. 4  than in  FIG. 5 . As shown in  FIG. 5 , the threaded grommet  64  allows the spacer  56  to be retained on the bolt  54  even when the distal end  94  of the bolt  54  does not extend past the grommet  64 , as shown in  FIG. 4 . 
     As noted previously with respect to  FIG. 3 , spacer  56  may be oriented in two different positions. One position is shown in  FIGS. 4-5  whereas the other position is shown in  FIG. 6 . In the position shown in  FIG. 6 , the barrel  66  of the grommet  64  is rotated  180  degrees from the position shown in  FIGS. 4-5 . This allows the distance between the guide  46  and the spacer  56  to be greater than that possible when the spacer is oriented in the manner shown in  FIGS. 4-5 . For example, in both  FIGS. 5 and 6 , the spacer is retained at the sixth lowest thread  70  of bolt  54 . However, because the spacer  56  has been rotated or inverted in the orientation shown in  FIG. 6 , the space between the guide  46  and the spacer  56  is greater than that of  FIG. 5  even though the top of the spacer  56  is retained on the sixth lowest thread  70  in  FIG. 5 . 
     When assembling the wall system  10 , the upper frame member  26  is secured to the wall panel  12 , and the wall panel  12  is then placed in a desired position on the floor  16  such that the upper frame member  26  is located adjacent and below the ceiling, shown at  80 . Spacer  56  is then secured to the flanges  34 ,  36  using screws  72 . This is followed by coupling the guide  46  to the spacer  56 . Once a proper height of the guide  46  has been attained by adjusting the position of the bolt  54  relative to the spacer  56 , one of the wall extensions  18 ,  20  is snapped into place, as described above. Noise and light abatement material  84 , such as foam, is then preferably placed into the cavity  82  defined between the ceiling  80  and the spacer  56 . The other wall extension  18 ,  20  is then snapped into place, thereby securing the noise and light abatement material  84 . 
     When assembled, the wall panel  12  is retained against the suspended ceiling  80 , without the use of fasteners penetrating ceiling  80 , by the noise and light abatement material and the lips  38 ,  40  of the wall extensions  18 ,  20 , respectively, in a manner that allows wall panel  12  to slip or sway in accordance with government regulations in response to a seismic event. The noise and light abatement material provides insulation against the ingress and egress of noise and light between rooms or spaces, and the variability permitted in retaining the bolt  54  in spacer  56  allows the wall panel  12  to be used in buildings of differing ceiling heights. 
     Referring now to  FIG. 7 , a corner brace  14  for connecting a pair of wall panels  12  to one another is shown. In the illustrated example, the corner brace  14  is adapted to connect wall panels  12  that are arranged perpendicular to one another, but it is recognized that the corner brace  14  may be modified to connect wall panels  12  that are inline with one another. Additionally, the corner brace  14  may be modified to connect more than two wall panels to one another. 
     In the illustrated example, corner brace  14  has an L-shaped body  96  that defines a first leg  98  and a second leg  100  that extends along an axis perpendicular to that of the first leg  98 . Holes  102  are formed in a spaced arrangement along the body  96  are designed to receive fasteners  104 ,  FIG. 1 , such as screws, bolts, pins, rivets, and the like, to connect each leg  98 ,  100  to a respective wall panel  12 . Since the wall panels  12  are generally free standing structures, the corner brace  14  functions to join adjacent wall panels  12  such that the wall panels  12  support each other. Thus, during seismic events, for example, the corner brace  14  functions to keep the wall panels  12  upright notwithstanding swaying of the wall panels  12  themselves. In other words, the connected wall panels  12  sway as a collective unit. 
     It is understood that the body  96  could be shaped to have more than two legs such that more than two wall panels  12  could be connected using a single brace  14 . For example, a three-way brace could be used to connect three panels together and a four-way brace could be used to connect four panels together. Additionally, while in a preferred embodiment each of the legs are perpendicular to one another, it is understood that for some applications it would be desirous for the brace to connect wall panels arranged at non-right angles to one another. 
     The present invention has been described in terms of the preferred embodiment, and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the impending claims.
A wall panel-ceiling engagement device is designed to couple a wall panel to a ceiling. The engagement device, when engaged with the ceiling, holds the wall panel stationary without any fasteners, braces or other securing members that penetrate into the ceiling. The engagement device includes a pair of wall extensions secured to opposite sides of the wall panel and that contain a sound and/or attenuating material, such as a foam material, therebetween. Corner braces are used to join adjacent wall-panels to one another. The corner braces also function to allow the wall panels to sway as a collective and connected unit during seismic events.