Abstract:
A seismic duty support system for a suspended ceiling at a wall intersection comprising a roll formed sheet metal wall molding, the wall molding having a vertical element and a horizontal element unitary with the vertical element at an upper edge of the vertical element, a plurality of supports regularly spaced along a length of the wall molding, the supports being attached to and extending perpendicularly from the vertical element, each of said supports lying in a vertical plane, each support having a hole distal from the vertical element for cooperating with a tension element connected to the end of an underlying grid runner.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to accessories for suspended ceilings particularly useful in seismic zones. 
     PRIOR ART 
     Various arrangements have been proposed to reduce the risk of suspended ceiling grid elements slipping off a wall angle at the periphery of a suspended ceiling during a seismic event. U.S. Pat. No. 8,453,407 discloses an example of a clip that can permit limited movement of the end of a grid runner off a wall angle without the grid runner falling. In some seismic zones, this type of clip may be deemed inadequate. Building codes may, for example, require that a grid runner at a ceiling perimeter be supported by an overhead wire within 8 inches of the respective wall and that the wire not be off vertical or plum more than 8.5 degrees. These requirements can often be difficult to satisfy, particularly where the wall rises only a limited distance above the plane of the ceiling. Even when the respective wall rises well above the ceiling, there may not be a practical or convenient manner of attaching a wire to the wall or wall framing. 
     SUMMARY OF THE INVENTION 
     The invention provides a wire or strap support for securing grid runner ends against accidental fall-off of a wall angle in the event of seismic activity. The support stands off a wall on which it is installed making the support readily accessible for installation of a suspension wire and reducing the required height above the ceiling plane to satisfy angle restrictions on the suspension wire or strap element. 
     In one embodiment of the invention, the standoff supports are stamped from and integral with the body of a sheet metal wall molding. The supports can be factory stamped out on 8 inch centers, for example, successively along the length of the wall molding. The supports can be left in the plane of the body of the molding. At the time of installation, certain ones of the supports can be selected and bent out of the plane of the associated part of the molding from which they were cut. The wall molding can be attached to a wall a short distance above the plane of the ceiling. 
     In another embodiment of the invention, a clip provides a standoff support for a suspension wire or the like. The clip preferably has a mounting part adapted to snap into engagement with a wall molding at a selected position along the length of the molding. As with the first-described embodiment, the wall molding need only be spaced a limited distance above the plane of the ceiling to avoid too great an angle from the vertical of the suspension element. 
     The disclosed supports enable the grid runners to be properly supported with reduced labor time and skill. Both embodiments of this invention allow the grid runners to be located on centers that are independent of the stud locations of the wall they intersect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a diagrammatic perspective view of a ceiling installation according to the invention; 
         FIG. 2  is a fragmentary front view of a wall molding according to a first embodiment of the invention; 
         FIG. 3  is an end view of the wall molding of  FIG. 2  showing a deployed standoff wire support; 
         FIG. 4  is a fragmentary elevational view of a grid runner attached to a wire support of the invention; 
         FIG. 5  is a side view of a standoff wire support clip of a second embodiment of the invention; 
         FIG. 6  is a front view of the clip of  FIG. 5 ; 
         FIG. 7  is a top view of the clip of  FIG. 5 ; 
         FIG. 8  is a fragmentary elevational view of a grid runner attached to the wire support clip of  FIG. 5  mounted in a wall molding; 
         FIG. 9  is a view similar to  FIG. 8  with a strap serving the function of a tension wire; and 
         FIG. 10  is a view similar to  FIG. 9  with the strap serving as the sole seismic safety support for a grid runner. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a suspended ceiling installation  10  where it intersecting a wall  11 . In the illustrated case, the wall  11  is constructed of sheet metal studs  12  covered with drywall panels  13 . The studs  12  and drywall  13  extend a limited distance above the plane of the ceiling  10 . In a conventional manner, the ceiling comprises grid runners  14 , ordinarily in the shape of inverted tees, forming a rectangular grid  16 . Ceiling tiles  17  are disposed in spaces between the grid runners  14 . Typically, main runners  14  of the grid  16  are suspended from overhead structure with wires on 4 foot centers. Throughout this disclosure, dimensions given in English units will be understood to extend to standard industry metric equivalents of such dimensions. 
     The ends of the runners  14  which essentially intersect the wall  11 , are disposed on a horizontal flange  18  of a wall angle  19  having a vertical flange  20  attached to the wall  11 . In seismic zones, a sheet metal clip  26 , such as disclosed in aforementioned U.S. Pat. No. 8,453,407 may be assembled on the end of a grid runner  14 . The clip  26  can be attached to the wall angle  19  by positioning depending tabs  27  of the clip  26  over the vertical flange or leg  20  of the wall angle. In certain seismic zones, there may be a need for a more positive support of a grid runner  14  at the wall  11  than is afforded by the clip  26 . 
       FIGS. 2-4  illustrate an embodiment of the invention by which a grid runner  14  is supported by a wire attached in close proximity to the runner end. A wall molding or angle  30  depicted in  FIGS. 2 and 3  is preferably a roll formed sheet metal unit. The wall molding  30  can be made of, for example, G-30 hot dipped galvanized steel of 0.018/0.021 inch thickness. The wall molding  30  can be supplied in 10 foot lengths, for example. The wall molding  30  is cut to length or joined with like wall moldings to span a wall. Distal longitudinal edges  31  of each wall molding leg or flange  32 ,  33  is stiffened by an inturned hem  34 . 
     Uniformly spaced along the length of the wall molding  30  are triangular supports  36 . The supports  36  are blanked or cut in the vertical leg  32  of the wall molding  30 . These supports  36  can be formed on 8 inch centers, for example. A vertical side of a support  36 , in major part, is formed by a relatively wide slot  37 . Above and below the slot  37  are land portions  38  where the support  36  remains integrally connected with the vertical leg  32 . Other side edges  41 ,  42  of the support  36  are fully severed from the vertical leg  32 . A hole  43  is blanked from the support  36  at a distal corner opposite the slot  37 . 
     The wall molding  30  is supplied to a building site with the supports  36  remaining in the plane of the leg  32 . Once a layout of a ceiling grid is determined so that the location of the ends of the grid runners intersecting a wall is known, the wall molding  30  can be installed. The wall molding  30  is installed on a wall a predetermined distance above the ceiling grid  16  with the support slots  37  in line with the future or actual centers of the grid runners  14 . The supports  36  can be bent and extended perpendicularly to the vertical wall molding leg  32  either before or after the wall molding  30  is installed on a wall. The wall molding  30  can be located lengthwise without regard to the location of wall studs or like structure since fasteners  39 , such as drywall screws for securing the wall molding  30  to the wall studs  12  can be situated wherever the studs exist along the length of the wall angle. 
     A standard suspension wire  46 , such as 12 gauge (0.109 in. diameter) steel wire, is looped through a preformed hole  47  in a reinforcing bulb  48  adjacent the end of a grid runner  14  and through the hole  43  in the support  36 . The wire  46  is twisted about itself to lock it in position. Since the supports  36  are aligned with the grid runners  14 , the wire  46  advantageously lies in a vertical plane through the grid runner thereby avoiding any side thrust on the grid runner as a result of a tension force in the wire. The “standoff” of the wire  46  from the wall  11  provided by the projection of the support  36  from the wall is beneficial. The wire  46  can be readily arranged to not deviate from the vertical by more than 8.5 degrees. With this near vertical orientation of the wire  46 , there is negligible horizontal force or thrust developed by tension in the wire even though the wall molding  30  and the support  36  is relatively close to the ceiling plane. The support hole  43  can stand off a wall 1¾ inches, for example. 
       FIGS. 5-8  illustrate aspects of another embodiment of the invention. Parts in  FIGS. 8 ,  9  and  10  that are identical to those described in connection with  FIG. 4  are identified with the same numerals. A support clip or bracket  50  is formed of a single piece of sheet metal, for example, 0.016/0.019 inch gauge hot dipped galvanized steel. In the plan view of  FIG. 7 , the support clip  50  has a right angle configuration. The clip  50  includes a base plate  51  and a support plate  52 . The base plate  51  has a pair of screw receiving holes  53  and the support plate  52  has a pair of holes  54  adapted to receive a suspension wire  46 . Upper and lower rectangular tabs  57 ,  58  extend horizontally from respective upper and lower edges of the base plate  51 . The clip  50  is proportioned to mate with a wall molding  60 . 
     The illustrated wall molding  60  is in the form of a U-shaped channel having flanges  61 ,  62  of unequal width and an intermediate web  63 . The wall molding or channel  60  is preferably made from roll formed sheet metal of, for example, 0.016/0.019 inch G-30 hot dipped galvanized steel. The distal longitudinal margins of the flanges  61 ,  62  have inturned hems  64  terminating at edges  65 . The wall molding  60  can be supplied in lengths of 10 foot. By way of example, the wall molding  60  can have a height of 1.862 inches, the upper flange  61  can have a width of 1 inch and the lower flange  62  can have a width of ½ inch. The wall molding  60  can be butt jointed with one or more identical pieces and/or can be cut to suit the length of a particular wall. 
     The wall molding  60  is secured to a wall  11  such as by self-drilling drywall screws  39  through the web  63 , drywall  13  and into studs  12  or other structural wall component. The support clip  50  is proportioned for the base plate  51  and tabs  57 ,  58  to fit within the wall molding  60 . Distal ends of the tabs  57 ,  58  snap into engagement with the channel hem edges  65  when the base plate  51  is close to or abuts the channel web  63 . 
     The snap-in retention of the support clip  50  in the wall molding  60  afforded by the tabs  57 ,  58  is a convenience to the installer since the clip need not be held in place while the installer performs related tasks. Ordinarily, the clip  50  is fixed in place with a self-drilling screw  66  located in one of the holes  53  and driven into the wall molding web  63 . It will be understood that there is no need for the clip  52  or, more significantly, for the grid runner  14  to be located at a stud center. The wall molding  60 , once fixed to the wall, is strong enough to hold the clip  50  when the clip is screwed or otherwise fixed to the molding. The strength of the molding  60  is enhanced by having a flange  61  at the top of the web  63  which greatly improves the resistance of the molding to buckling outward from the wall  11 . The clip  50  is tied to a grid runner  14  with a suspension wire  46  by threading the wire through one of the holes  54  and a hole  47  in the reinforcing bulb. As in the situation described in  FIG. 4 , the support clip  50  supplements the function of a seismic clip  26  and prevents a grid runner  14  from falling if it were to slip off the wall angle  19  during a seismic event. 
     As shown in phantom in  FIG. 8 , the wall molding  60  and clip  50  can be installed at a higher elevation relative to the plane of the ceiling  10 . In such a case, a suspension wire can be threaded through an inward hole and the wire would be within 8.5 degrees of vertical. 
       FIG. 9  illustrates a modification where a sheet metal strap  70  is substituted for the wire  46  of  FIG. 8 . The strap  70  can be permanently pivotally joined with a rivet or other fastening technique to the support plate  52  and can be attached to the reinforcing bulb  48  of a grid runner  14  with a self-drilling screw  71 . The screw  71  can be assembled in a selected one of a series of preformed holes  72  in the strap  70 . The strap  70  can save labor over the use of the suspension wire  46 . 
       FIG. 10  illustrates a situation like that described in connection with  FIG. 9  where the seismic clip  26  has been eliminated and exclusive reliance for suspension of the grid runner end is on the strap  70 , clip  50  and molding  60 . 
     While the invention has been shown and described with respect to particular embodiments thereof, this is for the purpose of illustration rather than limitation, and other variations and modifications of the specific embodiments herein shown and described will be apparent to those skilled in the art all within the intended spirit and scope of the invention. Accordingly, the patent is not to be limited in scope and effect to the specific embodiments herein shown and described nor in any other way that is inconsistent with the extent to which the progress in the art has been advanced by the invention.