CA1055220A - Suspended ceiling system - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A fire rated dry wall ceiling support system having fixed, aligned main beam members spliced together in a manner so as to absorb longitudinal compression, as for example resulting from thermal expansion during a fire.
Each main beam includes a web surmounted by a bead with flange portions extending laterally outwardly from the web. Each web end includes a tongue extending axially outwardly for locking engagement with the adjacent beam member web and is so configured that the tongues fold in a longitudinal manner and become laterally displaced out of the normal plane of the tongues when the beam members are longitudinally compressed towards one another. Accord-ingly, the bead means become laterally displaced while moving towards one another in a longitudinal direction and may in fact overlap one another in a longitudinal sense.
The system further includes support channels disposed trans-versely to the main beam members and engaged therewith. The main beams include pairs of longitudinally spaced slots which receive the ends of the transverse cross channels from both sides of the main beam. The ends of the cross channels are locked in the main beam slots. The slots and cross channel ends are designed to absorb thermal expansion in the transverse cross channels during a fire situation.
In addition the cross channels include a horizontal base portion which provides an effective mounting surface for dry wall ceiling panels.

Description

This inventionrelates generally to fire-resistant ceil-ing supporting systems and the like and, more particularly, to a supporting system for dry wall ceilings capable of absorbing thermal expansion in the system components with-out substantial buckling or collapsing of the dry wall ceiling during abnormally elevated tempera-tures, thereby preserving the integrity of the ceiling as a barrier under such conditions.
The present invention is particularly adapted for use in a dry wall ceil~ng grid system of the type comprising a plurality of parallel spaced main beam or grid members and cross channel support members extending transversely be-tween the main beam members and having end portions inter-locking therewith. These interlocked grid members generally are suspended from a conventional ceiling or an overhead support structure.
One of the critical problems encountered in supporting grid structures of the type referred to hereinabove is to maintain the integrity thereof and the associated ceiling under abnormally eleva-ted temperatures, such as accompany a fire. Under these high temperature conditions, the metallic members of the supporting system which generally are fixed at their opposite ends, expand and buckle whereby the supported ceiling panels are displaced and break away to such an extend that they drop to the floor below. As a result, the effectiveness of the suspended ceiling as a barrier is des-troyed and the overhead ceiling and related support structure is exposed to the fire whereby the latter lOSSZZO

can spread more easily and rapidly throughout the entire structure.
According to one aspect of the present invention there is provided a support grid system including a first support member having a web means associated therewith, the web having a pair of spaced slots therein, and a second support member, the second support member having laterally extending edge portions. The edge portions are resiliently biased away from one another and each respectively includes a notch in the end portion thereof, the end portions being correspondingly received in the slots so that the notches correspondingly engage the edges of the slots so that the second support member is retained in an assembled relationship with the first support member.
According to another aspect of the present in-vention, there is provided a first support member having a web means with the web means defining an opening configuration therein having a pair of spaced edges associated therewith.
A second support member is provided which has resiliently mounted, laterally extending edge portions, the edge portions being resiliently biased away from one another in opposite lateral directions and each respectively including a notch in the end portion thereof. The end portions of the edge portions are correspondingly received in the opening con-figuration so that the notches correspondingly receive the spaced edges of the opening configuration wherein each of the notches includes an elongated bottom edge correspondingly engaging one of the spaced edges of the opening configuration.
The bottom edges of the notches are of length greater than of width of the web means of the first support member and taper towards one another so that the second support member tends to resiliently cam away from the first support member ~ _ 3 _ -~", kh/~

due to the engagement of the tapered bottom edges of the notches against the spaced edges of the opening configuration.
Each notch includes shoulder means correspondingly overlapping one of the spaced edges of the opening configuration to pre-vent a complete withdrawal of the laterally extending edge portions of the second support member, the opening configuration whereby the second support member may displace toward the first support member resulting in the laterally extending edge portions and associated notches being urged towards one another.
An object of the present invention is, therefore, to provide a grid system with a specially configured locked connection at the intersection of the cross channel members with a main beam member which, in a preferred form, accomo-dates thermal expansion of the cross channel members without any significant effect on the orientation, in a lateral sense, of the main beam members.
The foregoing and other objects, advantages and characterizing features of the present invention will become clearly apparent from the ensuing detailed description of an illustrative embodiment thereof, taken together - 3a -.
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1 with the accompanying drawings wherein like reference characters denote like parts throughou-t the various views.
BRIEF DESCRIPTION OF THE DR~WINGS
Fig. 1 is a fragmentary, perspective view of a pair of connected main grid or beam members, one of which is intersec-ted by and connected to transversely disposed cross channel members on both of its sides;
Fig. 2 is a fragmentary, enlarged top plan view of the main beam members shown in Fig. 1 prior to relative longi-tudinal compression;
Fig. 3 is a view similar to Fig. 2 illustrating the relative longitudinal movement and lateral displacement of the main beam members after being subjec-ted to thermal expansion;
Fig. 4 is a fragmentary enlarged view of the end portion of a main beam member;
Fig. 5 is a fragmentary, enlarged view similar to Fig. 4 showing adjacent end portions of a pair of main beam members locked one to the other;
Fig. 6 is a longitudinal view, partly in section, of a pair of interlocked main beam members as taken about on line 6-6 of Fig. 5;
Fig. 7 is an isolated top view, partly in section, illustrating the locked connection of the adjacent ends of a pair of cross channel members to -the web of a main beam member;
Fig. 8 is a fragmentary, elevational view, partly in section, as taken about on line 8-8 of Fig. 7;
Fig. 9 is a view similar to Fig. 7 illustrating the 10552~0 1 relative longitudinal displacement of the cross channel members after being subjected to thermal expansion; and Fig. 10 is a fragmentary, perspective view of the end portion of a cross channel member.
DETAILED DESCRIPTION OF A PREFERRED EMBODIME~T
Referring now in detail to the illustrative embodi-ment depicted in the accompanying drawings, there is shown in Fig. 1 a dry wall ceiling grid system incorporat-ing a main T-support member, generally designated 10, connected in an end-to-end relation to another main beam member 10 as shown. Each of the main beam support mem-bers includes an upstanding web portion 12 which is sur-mounted by a bead means 14. Along the bottom edge of web 12 there is provided a laterally extending flange means 16. The adjacent ends of the main beam members 10 include connecting means for rigidly splicing beams 10 one to the other in an end-to-end relation as to be described in detail hereinbelow. In addition, the grid system includes cross channel support members 18 dis-posed transversely with respect to -the main beams and which have their respective ends interlocked in -the web of a main beam member. The interlocking of the cross channels 18 in the main beam webs will also be des-cribed in detail hereinbelow as forming part of appli-cant's invention.
Although not shown, it is to be unders-tood that dry wall ceiling panels are to be attached to the underside of the cross channel support members 18 and flange means 16, as for example through the use of metal screws which 1 could be engaged with such component parts of the grid system. In this regard, i-t is anticipated that the relative-ly greater planar surface provided on the bottom of the cross channels will be the principal surface to which the dry wall panels will be affixed although metal screws could be engaged with flanges 16. In this regard, it has been found advantageous to provide knurling on the bottom surface of the cross channels so as to facilita-te -the in-stallation of metal screws therein.
One object of -the present invention is to provide for thermal expansion along the several lengths of main beam members 10 and along the transversely disposed cross channels 18. If thermal expansion in the ~rid members was not provided for, then in the event of a fire and associat-ed extreme heat, there would be buckling of the grid mem-bers and relative disorientation among the same. According-ly -the present invention provides for limited movement of the grid members ~o as to accommodate the thermal expansion therein so that the mounting of the dry wall panels -thereto will not be broken.
Turning now to a consideration of Figs. 4 through 6, the end of the main beam member 10 shown in Fig. 4 in-cludes a tongue 20 extending beyond the end of -the web 12 with a tab 22 ex-tending beyond the end of the web 12 with a tab 22 extending axially outwardly from the tongue 20.
In addition, a tapered por-tion 24 is provided on -tab 22 for purposes of interlocking the tongue 20 to ano-ther main beam member as to be described more fully hereinbelow. A slight impression or cu-t 32 is provided in the metal material 1 approximately at the juncture of tab 22 and the locking portion 24 so as to facilitate bending of the latter with respect to the main body of tab 22. As clearly shown in Fig. 4, there is an opening provided in -the web 12 of the main beam and generally designated 26 in Fig. 4. The opening 26 comprises the deformation of a portion of web 12 laterally out of the plane -thereof so as to essentially form a closed loop 28 extending laterally out of -the plane of web 12 which is affixed to web 12 at its upper and lower edges 28a and 28b. As shown in Fig. 4, the deformed portion or loop 28 of the web 12 extends out of the rear side of the web.
Turning now to Figs. 5 and 6, it is to be seen -that the tongue 20 associated with the main beam on the right passes along the near side of web 12 of the main beam shown on the left. Necessarily, tongue 20 associated with the main beam on -the left passes behind and adjacent to tongue 20 ex-tending from the main beam on the right and passes through the punched out opening 28 in the main beam on the right, such opening or loop 28 extending rearwardly out of the plane of web 12 associated therewith. With tongues 20 being generally co-planar with webs 12, the axial center lines of the beams 10 are laterally displaced to a slight degree with respect to one another, such displacemen-t in this embodiment apprOximating the lateral thickness of the tongue/web-material, Of course -the beams 10 could be assembled in precise axial alignment by simply forming each tongue to be laterally off-set so as to complement one another.

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1 As shown in Fig. 1, the locking portions 24 depending from tabs 22 are bent outwardly so as to prevent with-drawal of the tabs 22 from the adjacent web opening defined by -the punched out loops 28. Accordingly, it has been found advan-tageous to provide a relief portion 30 in each web adjacent the opening therein and longitudinally aligned with the locking portions 24. As is to be appreciated from Fig. 6, the relief 30 enables the locking portion 24 to be easily bent outwardly from either side of the web. For example, a screw-driver could be inserted behind the locking portion 24 shown in Fig. 6 from either side of the web in order to bend the locking portion out-wardly. Furthermore, the partial shearing of the material at 32 between tab 22 and -the associated locking portion 24 facilitates the outward bending of the locking portion 24. Furthermore, in regard to Figs. 4 -through 6, it is to be noted that the leading edges 28c of the punched out portions 28 are flared outwardly. As to be described with respect to -the folding of tongues 20 upon one another when the main beams are subjected to longitudinal compression, -the relief provided by the outward flaring of edges 28c facilitates not only the initial engagement of -the tabs 22 but also con-tributes to the predetermined movement of the adjacent tongue 20. In describing the deformation of the main beam splice hereinbelow,it is to be understood that one skilled in -the art could employ a variety of splices similar to that described.
Turning now to Figs. 7 through 10, the attachment of cross channel support members 18 -to a main beam support 1 member will be described. As shown, each cross channel support member 18 is of generally U-shaped construction when viewed in transverse cross section. Such construc-tion includes a base portion 18a and leg portions 18b which are resiliently biased away from one another and which -terminate in laterally extending edge portions 18c.
Edge portions 18c have specially configured ends general-ly of a tapered or chamfered nature for reception in a corresponding pair of longi-tudinally spaced slots 34 provided in the web 12 of a main beam member. The ends of lateral edges 18c taper outwardly from -the extreme end point thereof to form a shoulder 18d. Extending from shoulder 18d is ano-ther outwardly tapering portion 18e which forms the bottom edge of a no-tch when viewed in combination with shoulder 18d. Figs. 7 and 8 illustrate the mounting and locking of the cross channel members 18 in the web 12 of a main beam 10. The extreme ends of the lateral edges 18c are inserted into a corresponding pair of slots 34. The slots 34 are generally shaped to receive the leading portions of -the legs 18b and include outwardly extending recesses 34a for interaction wi-th the leading tapered or chamfered por-tions of edges 18c, shoulders 18d and the bottom edge 18e of -the notch associated with shoulder 18d. Accordingly, as the cross channels are urged through -the web of the main beam, legs 18b are resiliently urged -towards one another until shoulders 18d pass by the web openings whereupon the;legs 18d snap apart to lock the shoulders 18d behind web 12 so as to prevent withdrawal of the cross channel member 1 therefrom. When the cross channels are not subjected to any type of movement as would be induced by thermal ex-pansiOn, the biasing of legs 18b away from one another and the outward tapering of the notch bottom edge 18e on the lateral ed~es 18c urges or draws the shoulders 18d up against the side of web 12 as is clearly shown in Fig. 7. As to be described, the elongated bottom notch edges 18e provide for thermal expansion of the cross channels. However, if no thermal expansion relief were -to be provided, the main body portion of edge 18c would only have to be spaced from shoulder 18d a distance approx-imating the thickness of web 12.
Necessarily, the cross channels 18 would be engaged with the main beam support members at appropriate spacings along th~ lengths thereof. For example, the main beams 10 could be provided wi-th pairs of slots 34 at eight inch spacings on center with the actual spacings of the cross channel members being at sixteen or twenty-four inch cen-ters. As is to be further viewed in Fig. 8, after the cross channels are engaged in slots 34, -the height of the lateral edges 18c above the base portion 18a generally corresponds to the height of the apex of recess 34a above flange 16 so that base portion 18a of the cross channel is supported by flange 16.
It is considered an advantage of the present invention that the cross channel members can be readily assembled with main beam support members by the simple insertion of the cross channels into the slots 34. Such assembly procedure does not involve the necessity of further assembling clips or other types of fastening devices to connect the cross channels to -the main beam. After the grid system is so assembled~ dry wall panels may be placed against the undersurface of flanges 16 and base portions 18a of the cross channels. Metal screws may then be engaged for example in the base portions 18a to retain the dry wall panels in place.
Turning now to a consideration of the manner in which the grid system operates when subjected to extreme heat 10 as associated with a fire for example, reference will be made to Figs. 2, 3 and 9. Fig. 2 illustrates two main beam members 10 spliced together as generally shown in Fig. 1 with locking portions 24 bent outwardly. Necessarily, tabs 24 could be bent fully around to abut against the adjacent punched out loop portion 28 of the adjacent~,~web.
The tabs 22 each include an upper and a lower edge which are closely fit with respect to the upper and lower edge portions 28a and 28b respectively of the deformed portion 28 of the web so as to prevent any substantial vertical 20 movement of the beam members relative -to each other.
Accordingly, as shown in~ig. 2, the main heamsj~are spliced together in a generally rigid manner. Upon being sub-jected -to heat, the main beams experience thermal expansion and having their end points fixed tend to compress toward one another. Upon the occurrence of such longitudinal com-preSsion/ the tongues 20 will buckle or fold since the Overlapping of the tongue edge portions 20a with respect to the upper and lower edges of the web loop portion 28 prevents further longitudinal movement of the beams toward 1 one another absent such folding or buckling of the tongues 20. In -this regard, the outward flaring of edges 28c on the web openings accommodates the folding of the tongues onto one ano-ther as shown in Fig. 3. The beam members longitudinally move toward one another while at the same time becoming la-terally displaced with respect to one anoth-er. If the longitudinal compression of the beam members is extreme enough, the relative lateral displacement there-between allows the bead portions 14 to overlap or pass by one another. During extreme buckling of the tongues 20 as shown in Fig. 3, the webs 12 of the beam members may tear to a certain extent below -thelrespective beads at a point adjacent to ~ongues 20 so as to result in the dis-placement shown. As indicated hereinabove, other tongue and locking arrangements could be provided which could provide for the lateral displacement of -the main beams during their respective expansions and which would embody the teaching of applicant's invention.
Similarly, the cross channels 18 may also experience thermal expansion and will tend to compress towards one another. In addition to such thermal expansion of the cross channel members, they also will be translated due to -the corresponding displacement of the main beam mem-bers 10. Accordingly, the cross channels 18, as shown in Fig. 9, may resiliently move toward one another by movement of the notched bottom edges 18e through the slots 34 where-by the leg portions 18b will tend to cam toward one another.
necessarily the length of bottom edges 18e would correspond to the potential degree of thermal expansion experienced by :1055Z20 1 the cross channels so that the main body of an edge portion 18c does not abut a web 12 in a compressive manner.
From the foregoing, i-t is apparent that the objects of the present invention have been fully accomplished in providing a grid support system for a dry wall ceiling which is readily assembled, can be easily disassembled if desired, and which is strong and rigid in use. Most importantly, -the aforesaid grid support system for a dry wall ceiling is fire rated for maintaining the integrity of a dry wall ceiling structure upon the application of heat thereto, thereby preserving its fire retarding qualities.
By the provision of the connecting splice means between the main beam members and the resilient, snap-locking naturé
of the connection for the cross channels to the main beam members, both longitudinal and transverse compression is absorbed in the grid system. Although the dry wall ceiling will possibly assume a drooping configuration upon extreme movementS of the grid system components, the integrity of the ceiling as a fire barrier will be preserved.
Having thus described and illustrated a preferred embodiment of my invention, it will be understood that such description and illustration is by way of example only and that such modifications and changes as made suggest themselves to those skilled in the art are intended to fall within the scope of the present invention as limited only by the appended claims.

Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A supporting grid system comprising: a first support member having a web means associated therewith, said web having a pair of spaced slots therein, a second support member, said second support member having laterally extending edge portions, said edge portions being resilient-ly biased away from one another and each respectively including a notch in the end portion thereof and said end portions being correspondingly received in said slots so that said notches correspondingly engage the edges of said slots so that said second support member is retained in an assembled relationship with said first support member.

2. A supporting grid system as set forth in claim 1 wherein each of said notches includes an elongated bottom edge engaging said slot edge, said bottom edges of said notches tapering towards one another so that said second support member tends to cam away from said first support member due to the engagement of said tapered bottom edges of said notches against said slot edges, and each said notch including shoulder means overlapping the respectively adjacent edge of said slot to prevent a complete withdrawal of said laterally extending edge portions of said second support member from said slots whereby said second support member may displace toward said first support member when said laterally extending edge portions and associated notches are urged towards one another.

3. A supporting grid system as set forth in claim 2 wherein said first support member includes a laterally extending flange and said second support member is supported above said flange of said first support member.

4. A supporting grid system as set forth in claim 2 wherein the bottom surface of said second support member is knurled so as to facilitate the reception of metal screw means therethrough.

5. A supporting grid system as set forth in claim 2 further including a third support member similar in form to said second support member and being axially aligned there-with and received in said slots of said first support member from the side of said first support member opposite to the side thereof through which said second support member is received.

6. A supporting grid system comprising: a first support member having a web means, said web means defining an opening configuration therein having a pair of spaced edges associated therewith, a second support member, said second support member having resiliently mounted, laterally extending edge portions, said edge portions being resiliently biased away from one another in opposite lateral directions and each respectively including a notch in the end portion thereof, and said end portions of said edge portions being correspondingly received in said opening configuration so that said notches correspondingly receive said spaced edges of said opening configuration wherein each of said notches includes an elongated bottom edge correspondingly engag-ing one of said spaced edges of said opening configuration, said bottom edges of said notches being of length greater than the width of said web means of said first support member and tapering towards one another so that said second support member tends to resiliently cam away from said first support member due to the engagement of said tapered bottom edges of said notches against said spaced edges of said opening configuration, and each said notch including shoulder means correspondingly overlapping one of said spaced edges of said opening configuration to prevent a complete withdrawal of said laterally extending edge portions of said second support member from said opening configuration whereby said second support member may displace toward said first support member resulting in said laterally extending edge portions and associated notches being urged towards one another.

7. A supporting grid system as set forth in claim 6 wherein said spaced edges of said opening configuration are disposed diametrically opposite to one another.

8. A supporting grid system as set forth in claim 6 or 7 wherein said opening configuration comprises a pair of slots spaced apart from one another.