Abstract:
An improved ceiling panel for use in concealed suspension is disclosed which includes framing a panel body member on the sides and rear face thereof in a manner that the lower surface of the panel is determined by the metal framing members. These members are preferrably extruded aluminum and hence the accuracy thereof and hence the accuracy of the lower surface of the panel can be maintained in a closer tolerance range. In addition the framing members include an inwardly directed flange which preferrably is held by an adhesive within an appropriately located kerfed recess in the edge of the body member. This structure serves to stiffen the panel and reduce deflection thereby providing a ceiling system of substantially improved quality. Height variations in ceiling systems are easily recognized and the present disclosure teaches a system of high quality while providing a system which is easy to install and has the advantages of ready access to the area above the ceiling.

Description:
This is a continuation in-part application of U.S. application Ser. No. 277,166 filed June 5, 1981, now U.S. Pat. No. 4,438,613. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to suspended ceiling systems which allow access to the area above the ceiling. In particular, the invention relates to concealed suspension ceiling systems having a structure which simplifies installation of individual ceiling panels and wherein improved reinforced panels are used to provide a system having improved alignment of individual panels and improved control of the positioning of the panel beneath the grid members. 
     BACKGROUND OF THE INVENTION 
     Many suspended ceiling systems have been proposed and are used extensively in building construction to improve the overall appearance of the office space, to allow access to the area above the ceiling where mechanical equipment and piping is often located, and to improve the acoustics of the space. Systems of this general type would include U.S. Pat. No. 2,101,349, U.S. Pat. No. 2,065,796, U.S. Pat. No. 3,430,338, U.S. Pat. No. 4,004,390, U.S. Pat. No. 4,027,446, U.S. Pat. No. 2,616,197, U.S. Pat. No. 3,279,139, U.S. Pat. No. 3,513,613, U.S. Pat. No. 4,019,300, Canadian Pat. No. 696,145 and Canadian Pat. No. 697,832. A suspended ceiling system is also disclosed in our pending Canadian Application Ser. No. 379,053 which corresponds to U.S. patent application Ser. No. 277,166 which are both assigned to the Applicant of the present application. 
     The problem with the prior art structures is that the main thrust, generally speaking, has been to provide a fairly simple inexpensive suspended ceiling system for use in a variety of applications, however, these systems although inexpensive are certainly not as attractive as a plastered ceiling. The earlier patents generally use what is referred to as a non-concealed system in that the individual grid members used to support the ceiling panels are exposed to the lower surface and as such are visible. More recently concealed ceiling panel systems have been proposed wherein the panels cover the individual grid support network and this is accomplished by having adjacent panels abut in one fashion or another. Generally, concealed ceiling systems are more expensive and therefore the quality of the system is superior. Several major problems occur with concealed ceiling systems, such as: 
     1. alignment of the edges of the panels to provide straight lines in both the length and width of the ceiling system; 
     2. control of the level of the individual panels beneath the grid work within a fairly narrow range as variation in the height of the panels is easily recognized from beneath due to light variations; and 
     3. an adequate air seal between the support grid and the ceiling panels. 
     The present invention is designed to alleviate the above problems of concealed suspended ceiling systems. 
     SUMMARY OF THE INVENTION 
     A ceiling panel for use with a suspended ceiling system, according to the present invention, comprises a body member of acoustical dampening material having at least one planar surface and having straight edges about the periphery thereof, generally perpendicular to the planar surface. L-shaped framing members are secured to the side of the body member to overlie a portion of the top of the panel and abut the side edges thereof. Each frame member includes an inwardly directed planar projection snuggly received within a kerf provided in the side of the body member. The frame member is bonded to the body member by an adhesive securing the projection within the kerf whereby this framed member, when secured to a body member, cooperates with the body member to stiffen the panel. It is important to have a relatively stiff panel as otherwise the panel will undergo substantial deflection due to its own weight and thus a noticeable variation in the height of the ceiling beneath the grid members will occur. Furthermore, such a reinforced panel has the periphery thereof bounded with the framing members whereby damage to the edge of the panel is minimized. 
     According to an aspect of the invention, the ceiling panel for use in a suspended ceiling system comprises a rectilinear flat body member of a thickness of between 1/2&#34; to 2&#34; and includes a plurality of extruded aluminum members to be applied to the periphery of the body member to bound the body member and protect the edge thereof. The body member is kerfed about the periphery intermediate the top and bottom surfaces of the panel to define a recess generally parallel to the lower surface of the body member. Each extruded aluminum member has a first arm and a second arm secured to form a right angle. The first arm includes a thin inwardly directed flange generally parallel to the second arm whereby the members, when applied to the edge of the body member, are secured thereto by an adhesive securing the flange within the kerf. When secured, the first arm is in engagement with the periphery of the body member and the second arm overlies and is in contact with the upper edge of the body member about the periphery thereof. 
     According to an aspect of the invention, the body member is of a thickness to lie within the frame whereby the planar surface of the body member is approximately coplanar with the plane defined by the lower edge of the first arms of said frame members whereby the lower edges of said first arms determine the lower surface of the panel. 
     According to a further aspect of the invention, a suspended ceiling system comprises a plurality of grid support members, a plurality of ceiling panels each having a body member and a reinforcing edge secured about the top edge of the panel and extending down the side edge thereof, spring means hingedly secured to each of the panels and releasably secured to one of the grid members, wherein the spring means maintains the panel in position against the grid members in one position and in a second position the spring means is selectively disengageable for suspending a ceiling panel system generally perpendicular to the grid members. The reinforcing edge includes a thin inwardly direct flange generally parallel to the top edge of the panel which is received within a kerfed recess in the edge of the body member. The reinforcing edge is secured to the body member by an adhesive applied to the flange prior to securement within the kerfed recess. 
     The panels of the preferred embodiment of the invention are rectangular and have four torsion springs secured thereto by clips engaging the corners of the panels. With this arrangement, the panels may be lowered and the torsion springs can selectively be disengaged from the grid system to allow hanging of the lowered panel, generally perpendicular to the grid system, along any edge of the panel or from any corner thereof. 
     According to yet a further aspect of the invention, a particular arrangement for securing and supporting the structural members defining the grid is provided which includes a plate member, which cooperates with a junction member designed to receive the structural members, wherein the plate and the junction member cooperate to position and secure the structural members in a manner whereby the lower extreme of the individual structural members define a plane when the junction members are properly suspended. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention are shown in the drawings wherein; 
     FIG. 1 is a perspective view of the grid system with one panel suspended below the grid system prior to being secured to define a portion of the finished ceiling; 
     FIG. 2 is an exploded partial perspective view of the junction member and plate used to secure individual structural members of the grid network; 
     FIG. 3 is a partial perspective view showing one junction point of the grid system with the various structural members secured and one panel shown in position beneath the grid system and a second panel suspended below the grid system generally perpendicular thereto; 
     FIG. 4 is a perspective view of the corner clip used in the suspension of a panel beneath the grid network; 
     FIG. 5 is a sectional view through a panel showing the reinforcing edge member secured within the body member of the panel with a cloth covering applied to the lower surface of the panel and about the side edges thereof; 
     FIG. 6 is a partial perspective cut away view of a panel with the reinforcing edge members applied about the periphery thereof with a cloth cover about to be applied to the lower surface of the panel (the corner of the panel has been removed to illustrate the securement of the edge member to the body of the panel); 
     FIG. 7 is a perspective view of a modified corner clip used for suspending of panels; 
     FIG. 8 is a top view of a corner of the panel with a modified clip secured to the panel; 
     FIG. 9 is a sectional view along lines 99 of FIG. 8; 
     FIG. 10 is an exploded perspective view of a modified method of connecting the structural grid members at a junction; and 
     FIG. 11 is a vertical section through the modified junction member when securing structural grid members. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The ceiling panel system of FIG. 1 shows a panel 2, suspended below the grid network 20 which is suspended from structural support members, one of which is shown as 22. The grid network 20 is rectilinear and each cell of the grid network is generally defined by four structural members generally identified as 24 interconnected at the corners thereof by junction members 26 having a plate member 28 secured atop the junction members. Panel 2 is secured beneath the grid network by torsion springs 30 secured at the corners of the rectangular panel 2. As shown in FIG. 1, the legs of the torsion spring have outwardly extending tabs 32 which engage a slot provided in the plate member 28 and therefore determine one position of the panel generally below the grid network in preparation for final positioning beneath the grid members. Therefore the panel is secured by clip members 60 in combination with torsion springs 30 provided at the corner of the ceiling panels with these torsion springs engaging a plate member provided above the grid network at each corner cell of the grid system. 
     Details of the method of securing the structural members of the grid network within the junction member, can be appreciated by reviewing FIG. 2. The junction member, generally shown at 26, is formed by the two components 44 and 46 slidably engaging one another. These components are preferably extruded and will be made of an aluminum or an aluminum alloy. At the centre of these components is a threaded aperture 42 for receiving the threaded I-bolt 36. Each of the structural members 24 has a notched portion on the upper flange of the sturctural member position adjacent the end thereof to align with the recess provided behind the out turned lips 52 of each of the arms 48 and 50 which define a slot for receiving the web of the structural member. As shown in the drawing, one of the structural members has been secured within the junction member as the U-shaped clip portion 54 overlies the upper flange of the structural member and is received within the recess portion of the structural member and within the slot like recess of the junction member behind the lips 52. In this manner, the structural member is secured to the junction member and cannot withdraw therefrom without removing of the U-shaped clip 54. Four clip members will provided for securing of the four structural members and after these have been secured, the plate member 28 can be secured to the junction member. Securement is provided by having I-bolt 36 pass through the central aperture 40, provided in the plate member, with this bolt subsequently being secured within aperture 41 of the junction member. After the bolt has been properly positioned to control the height of the junction member, and in so doing controlling the height of the grid network, nut 38 provided on the bolt is used to snug the plate against the clips thereby securing the structural members. In this way, pressure is applied through the clips 54 to the upper portions of the structural members thereby positively securing the structural members in the junction member and also positively positioning these structural members by pressing the upper flange 25 against the upper surface of the junction member. Therefore, the position of the height of the structural members within the junction member is accurately controlled and a high degree of precision of the junction member beneath the support steel is possible by adjusting the I-bolt. 
     The plate member 28 has been provided with recessed areas 56 spaced about the periphery of the plate member and inwardly of the junction member relative to a given cell of the grid network. These recesses are generally positioned to bisect the right angle between any two structural members and will be spaced outwardly of the junction members a sufficient distance to clear the lower flange of the structural members. These recesses are used to receive the legs of a torsion spring used in the securement of the panels beneath the grid network. 
     Further details, of the suspension of the panels, can be appreciated from FIG. 3 where one panel 2 is shown in snug engagement beneath the grid network and a second panel 2a is shown suspended below the grid network by one corner of the panel, generally perpendicular to the grid network. In this way an installer may grasp a torsion spring, associated with the one corner, lift the panel and suspend it from the grid system by forcing the legs 33 of the torsion spring into the recesses 56 provided in the plate member and the panel will be suspended in this position as the outwardly extending portion 32 of the legs of the torsion spring overlie the top edge of the plate. Therefore, in contrast to prior art systems, the installation of the panels and particularly the securement of the panels beneath the grid system, has been simplified and the installer need only suspend one corner initially and subsequently suspend the remaining corners in preparation for placement of the panels immediately beneath the grid network. One of the reasons that this is possible with the present system, is that each panel has been provided with a reinforced edge as reinforcing members 6 are secured about the periphery of the body member 4 of the panel 2. These reinforcing members have a first arm 10 and a second arm 8 secured to form a generally L-shape with a right angle therebetween. The first arm has an inwardly directing flange member 12 positioned about 3/4 of the length of the first arm below the second arm 8. This flange is generally perpendicular to the first arm and parallel to the second arm. These reinforcing members 6 are secured to the body member by providing a kerf in the edge of the body member sized to snuggly receive the flange 12 and an adhesive is applied, whereby the bonding of the flange within the kerf secures the reinforcing member to the panel. These reinforcing members accurately define the top edge of the panel and the perpendicular side edges of the panel, stiffening the panel and reducing deflection of the panel. The body member of the panel is normally made of a fiberglass having a density four to fifteen pounds per cubic foot, although it may be possible to provide a body member of other materials, such as mineral board or wood fiber board. As these reinforcing members are used to control the alignment of the panels and the dimension of the panels with respect to height, they are produced by extrusion in order to narrow tolerance variations. In addition, the body member 2, preferably before the kerf, has been provided the side edge thereof is passed through a belt sander to accurately control the dimension of the body member such that it does not extend below the laterally extending bead 14 of the first arm member. Thus it can be appreciated that the lower edge of the first arm member determines the lower periphery of the panel and therefore, as this reinforcing member is directly in contact with the grid network, accurate control on the lower surface of the ceiling is obtained due to the precision in the extruded components used in the present system. This is in contrast to prior art systems, which do not positively control the height of the ceiling in the manner of the present system. 
     The second arm of the reinforcing arm is provided with a raised bead portion 19 which is received within a recess 27 in the outwardly extending lower flanges of the structural members 24. This is a sealing bead which allows the panel, in combination with the grid network, to provide a sealed surface wherein the area above the ceiling can be used as a return plenum for a forced air ventilation system. 
     With respect to FIGS. 3 and 4, the actual securement of the panel to the plate, associated with the junction member, can be appreciated. A corner clip, generally shown as 60, has a thin base plate which is triangular and received beneath the second arm of the reinforcing members to provide a snug fit between the body member 4 of the panel and the second arm of the reinforcing members. This base member is forced under the second arms at the mitered corner of the panel and an upwardly extending torsion spring engaging member 62 is provided for engaging the coiled portion 31 of a torsion spring. In this way a pivot connection is provided between the clip member and the torsion spring to allow suspension of the panels, generally perpendicular to the grid system, from any side of the panel if two torsion springs are selectively disengaged and another two torsion springs remain engaged or to allow suspension of the panel from one corner thereof. The bonding of the flange member 12, within the body member, provides the only securement of the reinforcing members to the body, although further adhesives could be applied, however these have not proven necessary in most applications. This arrangement provides a very simple method for reinforcing the edges of the panels to protect them from damage and also simplifies the securement of panels beneath the grid network. 
     In FIG. 3, it can also be seen that a decorative cover member 16 has been secured to the lower surface of the body member by an adhesive and is applied about the lower edge of the first arm of the reinforcing member. This decorative cover, which is preferably made of cloth or other sheet goods, is cut on the first arm member 10 at position 18 below the alignment stud 29 of the grid network and the cloth is compressible and assists in concealing the alignment stud when two panels are secured beneath the grid network. In addition to concealing of the alignment lug, the laterally extending bead portion 14, of the first arm, provides a point of line contact for abutting panels to thereby simplify alignment and interengagement of the panels. The alignment stud 29 accurately aligns the panels both in the length and width of the ceiling system due to cooperation of the reinforcing members and this stud. Concealing of the stud is provided by the abutting beads 14 at the lower edge of the panels which is much easier to maintain than assuring abuttment along a substantial portion of the first arm member. This engagement is further simplified as the decorative cover is somewhat compressible thereby assuring full concealment of the alignment stud 25. 
     Turning to FIGS. 5 and 6, it can be seen how the laterally extending bead of the first arm accurately determines the lower surface of the panel and therefore, the lower surface of the ceiling system is accurately determined as the reinforcing member beneath the grid network is determined by the interaction of the reinforcing member and the structural members of the grid. As previously mentioned, the main reason for this is that the body member 4 of the panel is of a thickness to lie within the reinforcing members and the periphery of the panel is accurate due to the extruded reinforcing members. This is important in that the abutting edges of adjacent panels are essentially at the same position and therefore minor variations across the width of the panel would not be detected as they are corrected at the edge of the panel. For example variations in excess of 1/16th of an inch are not acceptable. The precision required is approximately 1/16th of an inch variation at the abutting edges of panels and the deflection across a length of a panel is limited to 1/360th of the span or less. The size of the panels generally used with this system are 5 feet by 5 feet or less and larger than about 2 feet by 2 feet. If larger panels are used, intermediate support is provided between corners of the panel in order to maintain the precision. Such support can be provided by mounting a sliding member on the top rail of the grid member slotted in a manner to receive the legs of a torsion spring either side of the grid member. 
     In FIG. 6, one reinforcing member 6a has been secured to the body member 4 and a second reinforcing member 6b is about to be applied to the body member with the flange 12 being received within the kerfed recess 29. An adhesive is applied to the flange 12 to provide an intimate bond of the body member adjacent the kerfed recess with the flange 12. In this manner, the reinforcing member is firmly secured to the body member and stiffens the panel. The particular placement of the flange, at approximately 3/4 of the distance below the second arm 8 of the reinforcing member, is important in that it provides a substantial portion of the body member below the kerfed recess 29, thereby avoiding problems due to cracking of the body member in the cutting operation and it also serves to increase the moment of inertia of the reinforcing member to reduce deflection of the panel. It is therefore preferable, to place the inwardly directing flange 12 as close to the lower surface of the body member as possible without causing problems during deflection of the panel or cutting of the panel to receive the flange. The greater the distance of the flange below the second arm the higher the moment of inertia of the reinforcing member. As mentioned, it has been found that with a panel of a thickness between 1/2&#34; and 2&#34; with the body member made of a fiberglass having a density in the range of four to fifteen pounds per cubic foot, that the flange can be placed approximately 3/4 of the length of the first arm member below the second arm. 
     The decorative cover 16, is shown secured to the panel of FIG. 5 and in FIG. 6 is shown in preparation for securement. Once the structural member 6b has been secured to the body member, the cover can be applied to the lower surface of the panel and secured thereto by an adhesive applied to the entire cover member. The first arm of each reinforcing member is provided with a small recess 17, whereby the cover member, when applied about the panel, may be cut by passing a knife through the cover member using the recess 17 as a guide. In this manner the cover is terminated below the position of the alignment stud when a panel is secured beneath the grid network and a sufficient side edge of the cover is provided to tightly secured the cover to the refinforcing members. This aspect is important, as the cover is used to conceal the alignment bead and good adhesion of the cover adjacent the laterally extending bead 14 is preferred. 
     A modified corner clip member is shown in FIG. 7 which can be made from an extruded aluminum T-bar which is subsequently been punched to define an opening 110 for securing the torsion springs generally as shown in FIG. 9. The modified clip generally shown as 100 in FIG. 7 includes a flat base member 102 from which the upright perpendicular member 104 extends. A gap is provided to allow the coil of a spring clip to be engaged as the coil can pass through the gap defined between the ramp member 108 and the end portion 106 of the engagement portion. 
     As shown in FIGS. 8 and 9 the clip member may be secured at the junction of two reinforcing edge members 6a and 6b at the corner of the panel. These top edge members in addition to being mitered at the outside edges thereof have a slightly wider gap generally shown as 120 to allow the clip to secure beneath the upright members with the perpendicular member 104 extending up through the gap 120. As shown in FIG. 9 the fiber body 4a has been locally deformed in the immediate area of the clip and this fiber member serves to retain the clip in snug engagement beneath the upper edges 8a and 8b of the reinforcing members. Furthermore it can be seen that the slot 120 is of a sufficient depth such that the clip member is contained within the area generally defined by the reinforcing edge members such that the end portion 106 when secured to a panel is above the reinforcing members and inwardly of the edges thereof. In this manner the gap defined between 106 and 108 which was of a sufficient width to allow a coil of a torsion spring to enter therebetween has now been decreased by the thickness of the reinforcing members such that the coil spring can not be accidently removed. As can be appreciated this provides a very simple system for maintaining this spring within the clip. Furthermore the reinforcing members now contact the upright edge 104 of the clip and assure that the clip is maintained at the corner and cannot slide longitudinally along the length of one of the edge members. This modified clip in combination with the modified top reinforcing edge members is preferred to the system generally as shown with respect to FIGS. 3 and 4. 
     A somewhat simpler arrangement for securing of the structural members 24a at an intersection thereof by using the junction members 200 having a body portion 201 and a top plate 28a. As can be seen, the body portion is closed on the bottom thereof and has an upwardly extending socket 202 for receiving the threaded I-bolt 36a. This I-bolt again passes through a central aperture 40a in the modified top plate 28a and applies a downward pressure on the structural members 24a to maintain securement of these members within the junction member. In contrast to the system shown in FIG. 2, the top plate 28a and the body member 201 may be secured by use of the I-bolt 36a and the associated nut 38a prior to securing of the structural members 24a therein. As can be seen, the plate 28a has been provided with apertures 208 for cooperating with pins 206 of the body member. In this way the orientation of the plate as secured to the body member 201 is predetermined. Once the plate has been secured to the body, by having the I-bolt engaged to socket 202 with the nut 38a being snug against the top plate 28a, the locking tang members 230 will be aligned with the slot defined by arms 204 provided to the outside of the junction member which receive the web 24 of the structural members. The structural members 24a may then be inserted into the junction member and will be retained in the slot between arms 204 due to the tang members 230 with their downward projection 232 being in engagement with recess 150 of each of the structural members. As can be appreciated, downward projection 232 provides a camming surface to allow assembly of the structural members and the opposite face assures the structural members are locked within the junction member in a manner to prevent inadvertent withdrawal. 
     The structural members contact the portions of the body member between the arms 204, these portions act as stop faces for the structural members. 
     The assembled structure can be seen in FIG. 11 where one of the structural members has been secured within the junction member and a second member is about to be secured by longitudinally inserting of the structural member. This tang member 230a is shown projecting above the normal plane of the plate 28a as it has not yet become engaged within the transverse groove 150 of the structural member. As described in reference to the earlier figures, fine adjustment of positioning of the junction member is possible as the socket 202 is of a sufficient height to maintain the I-bolt 36a at various positions and can be locked in this position by tightening of the locking nut 38a. 
     With this modified construction of the junction the structural members are cut to provide a different end portion generally shown as 210 where the faces of the structural members are perpendicular to the longitudinal axis thereof. This is a much simpler structure to produce relative to the more complicated end configuration required with the system as shown in FIG. 2. In contrast to the grid network shown in FIG. 2, the body portion of the junction member of FIGS. 10 and 11 is preferrably integrally cast of a zinc or aluminum alloy. 
     With the modified clip member of FIG. 7 and the modified reinforcing edge members of FIG. 8 and the improved junction member of FIGS. 10 and 11, installation of the system in the field is greatly simplified and problems such as longitudinal movement of the clip members, and difficulty in assembling the grid network are overcome. This system also allows very positive securement and placement of the grid members at the junction point as the upper edges 25 of the structural members are pushed against the upper edges slot 204 by the plate member 28a due to the pressure being applied by the nut 38a and exact positioning of the junction member beneath the support steel is easily achieved due to the fine adjustment provided as previously discussed. For these reasons, the system as generally shown in FIGS. 7 through 11 is preferred. 
     The present system provides a very accurate suspended ceiling system where the height of the lower surface of the ceiling system can be accurately maintained while realizing the benefits of forming the ceiling by using a plurality of ceiling panels. The ceiling panels require the reinforcing edge members, about the periphery thereof, which stiffen the panel and determine the lower surface of the panel particularly at the abutting edges of adjacent panels. This structure reduces light variations which occur when the ceiling system has vary heights. This system also simplifies alignment of the panels both in the length of the grid network as well as the width thereof. This is obviously important as the abutting edges do form a characteristics of the finished ceiling and this effect can be minimized if the lines are essentially straight as opposed to wandering about a straight line. Suspension of individual panels, particularly during installation, although it can also occur should access to the area above the ceiling be required, is simplified and the panels can be suspended from a corner thereof generally perpendicular to the grid network. The grid network is provided with junction members at each individual cell of the grid network which secure and accurately position the structural members of the grid in a predetermined fashion and also directly support the panels. In this manner, it is only necessary to adjust the height of the junction members and a very accurate grid system can be provided. This accuracy is translated to lower surface of the ceiling due to the extruded reinforcing edge members secured about each panel which abut the grid system in the finished form. 
     Although various preferred embodiments of the present invention have been described herein in detail, it will be understood by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope or the appended claims.