US3292332A

US3292332A - Suspended ceiling structure

Info

Publication number: US3292332A
Application number: US77452A
Authority: US
Inventors: Jahn Martin
Original assignee: Chicago Metallic Sash Co
Current assignee: Chicago Metallic Co LLC
Priority date: 1960-12-21
Filing date: 1960-12-21
Publication date: 1966-12-20
Anticipated expiration: 1983-12-20

Description

Dec. 20, 1966 M- JAHN 3,292,332

SUSPENDED CEILING STRUCTURE Filed Dec. 21, 1960 n 3 Sheets-Sheet l Dec. 20, 1966 M, JAHN 3,292,332

SUSPENDED CEILING STRUCTURE Filed Dec. 21. 1960 3 Sheets-Sheet 2 Dec. 20, 1966 v M. JAHN 3,292,332

SUSPENDED CEILING STRUCTURE Filed Dec. 2l, 1960 3 Sheets-Sheet 3 u MW WH.:

United States Patent Oce Patented Dec. 20, 1966 3,292,332 SUSPENDED CEILING STRUCTURE Martin Jahn, Chicago, Ill., assignor to Chicago Metallic Sash Co., Chicago, Ill., a corporation of Illinois Filed Dec. 21, 1960, Ser. No. 77,452 24 Claims. (Cl. 52-484) rl'he invention relates generally to intersecting runner elements, particularly for use in suspended ceiling systems.

In recent years suspended ceiling systems have become quite popular wherein metal runners are suspended by wires or similar elements to form la grid system composed of a plurality of intersecting runner elements, the latter forming the supporting frame work for ceiling panels or tiles. Two general types of runner grid systems are commonly employed, the first being an exposed in which only portions of the runners are enclosed Iand other portions are visible, Vforming .a framing for the panels or tiles, and the second being a concealed type of system wherein the panels or tiles are provided along their edges with means for receiving the supporting runners, whereby the latter are completely concealed, the edges of the panels or tiles abutting one another. The present invention is -applicable to either form of suspended grid system.

Recently the value of a suspended ceiling structure, employing panels or tiles which are made from relatively non-inflammable or fire resistant mineral materials, has become known, but the effectiveness of such a ceiling structure in connection with the :resisting or retarding `of re is dependent to a large extent on the appearances of the supporting -grid system. Obviously, even though the ceiling materials are relatively lire resistant, Vand thus tend to prevent the passage of .fire therethrough, at least offering a delaying factor with respect to the same, the effectiveness of the ceiling structure is dependent to a very large extent on the character of the lgrid system employed in supporting the relatively lire proof or lire resistant panels or tiles.

Thus assu-ming that the panels are supported by an exposed grid system wherein the panels rest upon exposed panel supporting portions, in the event of lire and excessive heat upon :the ceiling structure, the metallic runners of the grid system will tend to expand under the applied thermal load, such expansion comprising onequarter to one-half inch per eight foot length of runner or more. Such expansion, particularly when taking place in a series of aligned land abutting runners is capable of creating a considerable expansion and buckling of the ceiling structure, ultimately effecting a rupture in the ceiling expanse and permitting the lire to pass through the ceiling.

This action is particularly prevalent in grid systems wherein a plurality of parallel runners are employed comprising a plurality of runner sections placed in alignment and having their ends in abutting relation, the latter secured together by overlying couplings or clins, -as in such case the expansion is transmitted and multiplied from one end of the ceiling structure to the other. The expansion effect thus becomes cumulative and readily ruptures the ceiling structure. Consequently while the panel sections which are usually constructed from a mineral liber or the like which is heat resistant, the weak link in the chain becomes the supporting grid system and the heat resistance or fire resistance of such ya grid system may be measured substantially in terms of the eiectiveness of the grid system under the conditions involved.

In present grid systems it is common to employ two types of runners, one for use as continuous main runner sections adapted to be joined in end to end relation with like sections and connected at spaced intervals by suitable cross runners which are joined in intersecting relation to the main runners at intermediate portions thereof. It is common practice to form :the main runners with squared ends adapted to engage and abut like ends of an adjacent runner, such end portions being secured to Ia common coupling member which is provided with tongues or other means for engagement with the runners to lock them in :abutting rela-tion. Such main runners are no1'- mally disposed in spaced parallel relation and connected by the cross runne-rs which are provided with suitable projecting portions adapted t-o enter slots formed in the main runners, such slots being positioned intermediate the ends of the latter.

The present invention has yamong its objects the production of a suspended ceiling grid system which is so designed that each intersecting joint of the runner structure forms in effect an expansion joint which is capable of accommodating a predetermined amount of expansion, at least `adequate for :the members which may be connected in intersecting relation thereat and in particular where continuous end for end disposition of the runners is avoided, the construction being such that upon the application of heat to the ceiling structure, `as for example du-ring a lire, the deection of runners will tend to counteract or offset one another, so that lat each joint the tendency of one runner portion to move downwardly, will be 01T- set by the tendency of the Iadjacent runner or runners to move upwardly, such action tending to maintain the ceiling struct-ure substantially planar and substantially eliminating the tendency of the ceiling to rupture until sutlicient heat has been applied to cause the Imetallic runners to give way.

Another object of the invention is the production of a runner structu-re for use in grid systems having the above advantages which is so designed that only a single type of runner might be employed and which, if desired, may be constructed for cooperation with suitable elements by means of which connection of the runners is not limited to the intermediate 4portion of one runner but is such that the ends of the four runners may be secured together in operative position. l

A further object of the invention is the production of novell coupling and fastening means for securing adjacent runner sections in assembled relation, which is so designed that adequate expansion may take place at the joint thus formed.

A further object of the invention is the production of a novel runner structure which is so designed that adequate expansion may take place under high thermal load, the runner being designed to provide a `deformable end portion which will sufliciently deforim upon the application of heat to permit deforming, such as overlapping thereof with a transversely extending runner to eliminate the application of excessive bending forces to such transverse runner.

A further object of the invention is the production of a novel runner structure which is so designed that intermediate portions of the runner may distort under the application of heat without producing undue bending of the runner structure.

Many other objects and advantages of the construction herein shown and described will be obvious to those skilled in the art from the disclosure herein given.

In the drawings, wherein like reference characters indicate like or corresponding parts:

FIG. l is an exploded perspective View of an intermediate portion of 4a runner to which the ends of two transversely extending runners are to be secured, together with an attaching clip therefor;

FIG. 2 is a perspective view of the runner structures illustrated in FIG. l, the runners being illust-rated in interlocked and attached relationship;

FIG. 3 is a side elevational view of a runner section, with portions thereof broken away;

FIG. 4 is a diagrammatic view of a suspension grid system employing the present invention;

FIG. 5 is a semi-diagrammatic plan view of a grid system embodlying thel present invention, illustrating; some of the possible combinations which may be employed;

FIG. 6 is an exploded perspective view similar to FIG. 1, illustrating the application of the invention to `a four-way intersection employing a coupling element;

FIG. 7 is a plan sectional view of the elements illustrated in FIG. 6 following interlocking thereof;

FIG. 8 is a side elevational view of a pair of runner ends illustrating the manner in which they may be locked in aligned relation;

FIG. 9 is a sectional view taken approximately on the line 9--9 of FIG. 8;

FIG.- 10 is a sectional View through a runner intersection taken approximately on line 10-10 of FIG. ll and illustrating a modied form of interlocking structure;

FIG. 11 is a sectional view taken approximately on the line 11-11 of FIG. 10;

FIG. l2 is a plan view of a runner end with a portion of the top bead lbroken away;

FIG. 13 is an end elevational view of a modified runner construction embodying a runner body and ornamental cap; and

FIG. 14 is an end elevational view similar to FIG. 13 of a modified form of runner.

Referring to the drawings, and more particularly to FIGS. l, 2 and 3, the reference numeral 1a indicates generally an intermediate portion of a runner, while the numerals 1b .and 1c represent end portions of two other runners, all of the runners preferably Ibeing of identical construction. Each runner may comprise an upright center stem or web portion 2 terminating at its upper longitudinal edge in a tubular bead 3 and formed at its lower longitudinal edge with a ange indicated generally lby the numeral 4, forming the outer exposed face of the runner, and adapted to support the ceiling panels, for example, the panels P, illustrated in dotted lines in FIGS. 10 and ll.

In the construction illust-rated, the ange face portion 4 is integrally formed with the web or stem portion 2, the metal forming the same being bent at right angles as indicated at 5 and then folded back upon itself as indicated at 6, the free edge of the flange lbeing folded back upon its edge as indicated at 7 to provide a reinforcing edge strip 8.

As illustrated in FIG. 3, each end of the runner 1a, and in like manner runners 1b and 1c, are provided at their ends with tongue members 9 formed from the body of the web portion 2 and provided wit-h a longitudinally extending slot 11 therein. Likewise, each web portion 2 may 4be provided with one or more vertically extending slots 12 of a size to receive the tongue portion 9 of a cross runner abutting the same. The numlber of slots 12 in each runner will depend upon the length of the runner, such slots being symmetrically disposed whereby the runners may be assembled in modular form. Thus assuming that a two-foot module base were employed, the runners would normally be fabricated in two, four, six,

and eight foot lengths, the slots 12 being disposed two feet apa-rt, and the overall length of each individual `runner being such that when assembled with other runners, the two foot modular system will be maintained, the runners extending with spacings of two feet or a multiple thereof. Obviously, if a one foot base were employed, the runners would be provided with slots twelve inches apart to conform to the particular base employed.

The runners are `adapted to be supported `in the same manner as in prior devices of this type, as for example,

by the use of supporting wires or the like, and to facilitate such suspension, the runner preferably is also provided The runners illustrated in FIG. 1 may bel assembled in interlocking relation in the manner illustrated in FIG.4

2, wherein the tongues 9 of the runners 1b and 1c are inserted from opposite sides of the runner 1a through the slot 12 therein, the end edges 14 of the runners 1b and 1c abutting the respective sidel edges of the face portion 4 of the runner 1a. The assembly is interlocked in assembled relation by suitable means such as a wire clip 15 which is illustrated as comprising two generally coextensive leg portions 16 connected by an intermediate U-shaped portion 17, the latter extending transversely to the legs 16. As illustrated in FIG. 2, the clip 15 is` engaged with the interlocked runners by inserting the free ends 18 Lof the clip through the slots 11 of the runners 1b and 1c, the legs 16 Aof the clip disposed at,

opposite sides of the web 2 of the runner 1a, so that each leg passes through the portions of the tongues 9 dis-v posed vat the adjacent side of the runner 1a. If desired,

the legs 16 of the clip may be provided with inwardly disposed indentations or notches 19 adapted to engage the tongues to tend to restrict longitudinal movement of the legs of the clip with respect to the tongues engaged` therewith. Likewise, the free ends 18 of the legs may be formed to slightly diverge, as clearly illustrated in FIG. 1 to facilitate t-he insertion of the legs through the tongues of the runners. As illustrated in FIG. 2, the

length of the U-shaped portion 17 is such as to enable` the same to seat upon the bead 3 of the runner 1a, the

leg portions extending generally parallel to the face '4l of the runner 1a.

As illustrated in FIGS. 4 and 5, grid systems formed solely from runners constructed as illustrated in FIGS. l, 2 and 3 may be readily fabricated.

It will be noted that the grid structure illustrated in` FIG. 4 is `composed of a plurality of runners, all of the same length, and all of which, for example, may be constructed as disclosed in FIG. 3, the runners in such case having a module -base of three so that each runner has at least two slots 12 therein, in effect, dividing the runner into three sections of uniform effective length.

It will be noted that in the design of FIG. 4 each runner has its ends terminating at an intermedi-ate portion of a runner extending transversely thereto, each juncture being generally T-shaped rather than X-shaped.

Suspended ceiling structures of the type here involved, embodying fire resistant ceiling panels and metal runners, provide a very effective fire resistant or retarding struc-A ture, provided that the structure, under the application of heat, remains substantially intact without the formation of ruptures therein which would permit the heat or flame to pass through the structure. This aspect is complicated by the fact that T-shaped structures of the type involved, particularly when the upper part of the structure is insulated by panel members, upon the application of heat from below, initially expand at the flange or bottom portion thereof to a considerably greater extent than at the upper portion, so that the greater expansion at the bottom tends to bow the runner, whereby the ange or face of the runner is convex with the ends turning upwardly. The present invention enables the construction of a ceiling grid system wherein the runners are so disposed that at least one intermediate portion of `each runner is joined by an end of a cross runner, so that the upward movement of the end portions of the runners tends to counteract the downward movement of the central portions thereof, thereby tending to equalize and maintain the entire suspension in a relatively planar position to avoid rupturing of the system.

Obviously, with continued application of heat, the distribution Will increase as the temperature of the various portions of the runners approaches uniformity so that the expansion problem is of importance primarily during the initial applicati-on of heat.

FIG. 4 illustrates a grid system wherein each runner is three units long, the ends of the runners abutting an intermediate portion of the transversely extending runner associated therewith so that the expansion in the runner length is accommodated by an intermediate portion of the runners interlocked with the ends thereof and at no portion of the system is there a cumulative action which would create a rupture in the ceilingr suspensions. As hereinafter described, the runners may be so designed that they will permit an adequate amount of runner expansion without serious distortion of the cross runners and in such cases the lgrid system may be designed with joints consisting of an intermediate portion of one runner and the end portions of two aligned runners, one on each side of the rst runner as well as designs wherein the end portions of four runners are joined together, as for example, by means of a suitable coupling member. FIG. 5 illustrates designs employing such types of intersections and obviously the basic pattern may be varied by interposing additional short cross runners in subdividing relation with respect to the main longer runners. FIG. 5 illustrates various `combinations that could be employed in such construction.

In the constructions illustrated in FIGS. 1, 2 and 3, the end portions of the ange or face 4 of thel runners are suitably constructed to permit the end portion thereof to deform in the event excessive pressures are applied thereto7 :as for example, those resulting from engagement of the end of one runner face with the edge of a transversely extending runner .as illustrated in FIG. 2, during application of heat to the ceiling structure. In the embodiment of FIGS. 1 and 2, the connecting portion 5 of the runner is cut away adjacent the free end 14 of the face portion 4 as indicated at 19, leaving a small edge portion 21 of approximately the same width as the portion 8 at the opposite edge of the face portion 4, the web 2 being slightly cut away as indicated at 22 to provide clearance over the adjacent portion of a transversely extending runner as clearly illustrated in FIGS. 2 land 10. This construction permits the extreme end portion of the web to slightly overlie the transversely extending runner, thereby preventing undesired vertical movement between the runners, such portions preventing the end of the engaged runner from moving downwardly with respect to the adjacent intermediate runner portion and thus out of proper alignment.

The metal forming the runner is of such a gauge that the end portion as defined by the cutaway area 19 is sufciently reduced in strength that it will deform under the application of longitudinally directed expansion forces. Referring to FIG. 2, it will be noted that the slots 11 are considerably longer than required to permit insertion of the locking Iclip so that the tongue 9 will not restrict movement of either the runner 1b or 1c toward the runner 1a and likewise the beads 3 terminate at a point to permit such movement. Consequently, upon the application 'of heat to a joint as illustrated in FIG. 2, expansion of the runners 1b and 1c will primarily result in pressure being developed in the end portions of such runners due to their engagement with the

edges

6 and 7 of the runner 1a, but instead of buckling the joint, the weakened p0rtions of the flange or face portions 4 of the runners 1b and 1c may `defor-m, either crumpling, or being sprung downwardly to ride underneath the flange or face 4 of the runner 1a, thereby providing adequate expansion of the runners and eliminating undesired buckling and rupture of the ceiling which would otherwise take place. As hereinvafter illustrated and described, modifications in the means for permitting such expansion may be employed.

FIGS. 6 through 9 illustrate the joining of runner ends by the use of coupling members or the like, FIGS. 6 and 7 illustrate the manner in which the ends of four runners may be joined together, and FIGS. 8 and 9 illustrate the manner in which a pair of aligned runners may be joined.

All of the ends of the runners 1b, 1c, 1d and 1e, in the embodiment illustrated, are constructed in the same manner as the runners of FIGS. 1 and 2, the tongues 9 of the runners 1d and 1e, however, being bent intermediate their ends to form end portions 23 extending at right angles to the plane of the web 2 and thus to the remaining connecting portions of the tongues 9. Such bending may be readily accomplished by the installer by use of a pair of pliers or the like, and to facilitate bending at the proper place the tongues may be provided with suitable lines 24 or yother indicia by means of which the location of the bend may be readily and accurately determined. Such identifying marks may be Vstamped or applied by any suitable means to the tongues 9.

Cooperable with the runners is a coupling member or clip indicated generally by the numeral 25, which is formed in approximately the same manner as the runners, so that the transverse cross section of the intermediate portion of the coupling member is substantially the same as the cross section of a runner, the coupling member illustrated having `a web 26 terminating at its upper edge in a pair of longitudinally aligned bead portions 27a and 27b, which are separated by a slot 28, which permits the beads 27a and 27b to be formed in opposite directions, with the full longitudinal edge of the bead 27a and the adjacent face of the portion 26 defining a longitudinally extending slot 29a and the full edge of the bead 27b and the opposite face of the portion 26 defining a similar longitudinally extending slot 29b. Carried at the lower edge of the web portion 26 is a ange or face portion 30, corresponding to the portion 4 of the runners, the portion 30 being integrally connected to the web 26 by a connecting portion 31 corresponding to the portion 5 of the runners, and in like manner the free edge of the portion 30 may be provided with a reinforcing strip 32. The web portion 26 is also provided with a slot 12 formed therein corresponding to the like slot in the intermediate portions of the runners and of a size to receive tongues 9 of the runners to be attached.

As clearly illustrated in FIGS. 6 and 7, the bent portions 23 of the tongues of the runners 1d and 1e may be bent in opposite directions so that the runners may be assembled to the coupling in the manner illustrated in FIG. 7, wherein the runners 1b and 1c are inserted in the same manner as the corresponding runners in FIG 2, the runner 1d having its tongue portion extending along the side of the web 26 as the runner 1c and the extreme end portion 23 of the runner being inserted in the slot 12 to thereby position such end adjacent the runner 1b. In like manner the tongue 9 of the runner 1e is disposed at the side of the web 26 adjacent the runner 1b, the free portion 23 of the tongue extending through the slot 12 adjacent the runner 1c. Following assembly of the runners and couplings, the entire assembly may be interlocked by means of the wire clip 15, the leg portion 16 of the latter extending through the slots 11 of the runners 1b and 1c and the portion of the slots 11 of the runners 1d and 1e disposed in the end portion 23. Thus the runners 1b and 1c may be interlocked to the coupling member 25 in the same manner as the corresponding runners of FIG. 2 are interlocked to the runner 1a and the runners 1d and 1e may be interlocked by means of the transversely extending end portion 23.

The insertion of the tongues 23 in the slot 12 may be readily accomplished by engaging the coupling 25- initially with the runners 1d and 1e. One runner 1e for example may be engaged with the coupling by positioning the bead 3 of the runner in alignment with the bead 27a of the coupling and the planes of the

web portions

2 and 26 being disposed at an angle to one another suicient to permit the end portion 23 to pass along the left hand face of the web 26, as viewed in FIG. 6, so that upon longitudinal movement of the runner and coupling toward one another, the bead 3 of the runner may enter the bead 27a of the coupling, and the adjacent portion of the web 2 entering the slot 31a, the latter being of a width to receive the portions 26 when the latter is in such angular relation. The bead 3 of the runner may then be inserted in the bead 27a a distance sufficient to position the transversely extending portion 23 of the tongue 9 in alignment with the slot 12, at which point the runner may be rotated to bring the web portion 2 thereof into parallel relationship with the web 26 of the coupling member, simultaneously inserting the portion 23 of the tongue 9 through the slot 12 to the position illustrated in FIG. 7. The runner 1d is similarly assembled with the coupling member, the bead 3 entering the bead 27b, it being noted that the slot 31b of the bead 27b is disposed at the opposite side of the web 26 to permit insertion of the tongue 23 of the runner 1d from the right hand side of the web as viewed in FIG. 6. Following assembly of the runners 1d and 1e with the coupling member, the runners 1b and 1c may be engaged therewith in the same manner as the runners 1b and 1c of FIG. 2 are engaged with the runner 1a, following which the wire clip may be interlocked with the tongues of the respective runners as clearly illustrated in FIG. 7.

Where coupling members such as the member 25 are employed in heat resistant structures, the position of the coupling member, preferably is reversed at each successive joint. Thus, assuming a grid structure wherein each joint comprises the ends of four runners in the manner illustrated in FIGS. 6 and 7, the coupling members would be alternately reversed with the coupling member at either end of the runners 1d and 1e extending transversely thereto and connecting the runners corresponding to the runners 1b and 1c.

FIGS. 8 and 9 illustrate the joining of two longitudinally aligned runners 1, each of which is constructed in the same manner as the runners heretofore described, the runners being engaged by a coupling member 33 having a single bead portion 34 of a size to receive the beads 3 of the respective runners, the portion 35 corresponding ,to the web portion 26 of the coupling 25 with the lower edge 36 being disposed adjacent the ange 4 of the runner. As clearly illustrated in FIGS. 8 and 9, the coupling member may be provided with suitable locking means such as a tongue 37, illustrated as being formed from the portion 35, which normally extends at right angles to the plane of such portion as indicated in dotted lines in FIG. 9. Following insertion of the beads 3 of the runners 1 into the bead 34 of the coupling member, which may be accomplished by rotating the coupling member to bring the portion 35 in angular relation to the Webs 2 of the runners, the coupling member may be rotated in a counterclockwise direction as viewed in FIG. 9, thereby inserting the tongue 37 through the slots 11 in the tongues 9 of the runners, and bringing the portion 35 of the coupling in parallel relationship to the webs 2 of the runners. Following such insertion, the free end 38 of the tongue 37 may be bent upwardly as illustrated in FIGS. 8 and 9, thereby interlocking the coupling member to the runners.

The space between the ends of the flange portions 4 of the runners 1 may be closed by suitable means such as a cap member 39, formed from very light material and bent along its longitudinally extending edges as indicated at 41 to provide reversely extending anges 42. Thus the cap member may be applied to the aligned anges 4 of the runners prior to the application of the coupling member 33 and if desired the flanges 42 may be deformed or sheared inwardly at suitable points asi` indicated at 43 to provide abutments engageable with the adjacent ends of the flanges 4 of the runners, thus` retaining the cap member 39 in opeartive position as illustrated in FIG. 8.

It will also be appreciated that if desired the coupling 33 could be provided with a ange portion correspond-1 i ing to the portion 30 of the coupling 25, thereby eliminating the need for a separate cap member 39. It will` be appreciated that in the event of expansion of the run.-` ners, the cap member 39 is of suciently light material.

that it may be readily deformed to permit necessary expansion.

FIGS. 10, ll and l2 illustrate runners having a modi.

ed tongue structure in which the parts are interlocking without the use of a locking clip such as the clip 15 of` the previously described constructions. These gures also illustrate the use of a runner in which the web portion Referring to FIGS. 10 and l1,` the webs 2' of the runners 1f, 1g and 1h comprise two is of double thickness.

plies 2a and 2b formed by folding a strip of material back upon itself, the intermediate connecting portion being tubular shaped to form a generally cylindrical bead 3'..

The free edges of the strip opposite the bead 3 are bent laterally outwardly in opposite directions to form oppositely disposed aligned flanges 4a and 4b which may be` As clearly illustrated in FIGS. 11 and l2, the runners` are provided at each end with a tongue portion indicated` generally by the numeral 9' which is divided into sections 9a and 9b by a slot 45 which may have a generally cir-` cular inner portion 46. The outer corner portion of each` tongue is cut along the diagonal as indicated at 47, each tongue section being provided with an abutment 48 thereon adapted to engage an intersecting runner. The proportions of the tongue 9 are such that they may be inserted in a slot 12 in the web 2 of a transversely extending runner, the slot 45-46 providing adequate resiliency in the tongue portions 9a and 9b to permit the latter to move toward one another under the camming action of the diagonally extending edges 47, as the tongue is inserted in a slot 12, permitting the tongue to be fully inserted into the slot, as illustrated in FIG. 10 with the portions of the tongue springing outwardly again following passage of the head or enlarged portion of the tongue through the 1 slot, whereby the abutments 48 may engage the adjacent portions of the web 2.

As illustrated in FIG. l2, the tongues 9 preferably are of only a single thickness of metal, the tongue on one by side relationship, the central axis of the runners will be in alignment with no oifsetting from one runner to the next.

To achieve the desired fire resistant characteristics heretofore described, and permit expansion of the runners under application of heat thereto, the ilanges 4a and 4b` of each runner may be cut away adjacent the ends of the latter as indicated at 19', leaving only a pair of relatively i narrow strips 49, each of which generally corresponds to the strip 21 of the construction illustrated in FIGS. l and 6, to provide a rein-forcement for the light cap, such reinforcement, however, being insufficient to resist such expansion and thus permits the end of the cap to deform from engagement with the cross runner upon the applical tion of heat to the system and expansion of the runners.

The construction illustrated in FIGS. through 12 is also adapted to be assembled by means of coupling members similar to the coupling members 25 or 33, the web portion of the coupling preferably being formed to dispose the slot through which the tongues 9' may enter, at right angles to the plane of the web portion of the coupling, this being readily accomplished by suitable stamping operations. Similarly, in such cases the coupling member could be constructed with a liange portion similar to that illustrated in FIGS. 1, 2, 6 and 7, or in additional cap member similar to the cap 39, illustrated in FIGS. 8 and 9, could be employed.

Y It will also be noted that a coupling very similar to that illustrated in FIG. 6 could also be employed and two of the tongues 9 bent at right angles, whereby four ends could be engaged with the, coupling member in a manner very similar to that illustrated in FIGS. 6 and 7.

While I have illustrated in the previously described constructions runners which are constructed at the ends of their ange or face portions, with means that will permit'deformation of such end lportions under the action of thermoexpansion of the runner, if desired such compensation for expansion could take lplace longitudinally along the runners rather than at'the ends, and FIGS. 13 and 14 illustrate two modiiied Iforms of runner structures wherein such expansion is achieved along the longitudinal edges of the runners.

l Both of these constructions employ a two-ply web structure similar to that illustrated in FIGS. 10 to 12, and embodying an ornamental cap.

In the construction illustrated in FIG. 13, the web portions 2c and 2d ofthe runner 1k extend in parallel relation throughout their length and terminate at their lower ends in outwardly extending ange portions 49 similar to the anges 4a and 4b in the construction illustrated in FIG. 10, but of lesser transverse width. Engaged with the anges 49 is a cap member 51 of relatively thin material having its free longitudinal edges folded back as indicated at 52 to provide a channel for the reception of the anges 49 of the runner structure. To insure retention of the cap 51 in aligned relation with respect to the web of the runner, and flanges 49,1if desired, the portions 52 of the cap member may be provided with spaced indentations 53 adapted to engage the longitudinal edges of the flanges 49, thereby preventing undesired lateral shifting of the cap relative to its supporting anges. Such projections 53 may, if desired, be staggered along opposite edges of the runner as clearly illustrated in FIG. 13.

In the construction of FIG. 14, the runner 1m is constructed very similar to the runner 1k of FIG. 13, with the exception that the lower portions of the webs 2e and 2f diverge as indicated at 54, thereby positioning the edges of the tlanges 49 in engagement with the connecting portions S5 of the cap 51, so that the cap is rigidly held in position on the runner structure.

The operation of the runners illustrated in FIGS. 13 and 14 is generally similar and in the event transversely extending runners are engaged with the runners 1k or 1m, upon expansion of the ilange portion of such cross runners, pressure will be exerted upon the cap member 51, which being of light material will readily deform, permitting the'cross member to move inwardly. The same action will take place with respect to the construction of FIG. 14, with the exception that in this case the force of expansion, in deforming the cap 51 will also move the anges 49 toward one another, the portions 54 functioning in the manner of semiresilient portions, which will readily permit such inward movement of the anges.

It is believed apparent that .any one ofthe forms of the invention illustrated may embody longitudinally deformable elements similar to those illustrated in FIGS. 13 and 14, or if desired, a combination of elements may be employed.

Likewise, While I have illustrated the deformable portions as being generally planar, they may be suitably formed, as for example, in corrugations or other configurations which may impart an ornamental appearance in addition to the functional results.

It will be noted from the above description that I have provided a novel runner structure wherein an entire grid system may be fabricated from identically constructed runners, either of the same length or of varying lengths and I have provided a novel arrangement whereby all joints or junctures between the runners may involve a single runner end in engagement with an intermediate portion of a transverse runner, so that expansion of the abutting runner is transmitted to the intermediate portion of the transverse or cross runner, the latter readily absorbing any reasonable expansion in the length of the abutting runner.

It will also be appreciated that I have provided a novel runner structure wherein four runners may be joined together at their ends by means of novel coupling elements, or a pair of runners may be joined in aligned abutting relation whereby substantially complete exibility of design may be achieved, employing merely a single type of runner in various lengths.

Having thus descri'bed my invention, it will be obvious that various immaterial modiiications may be made in the same without departing from the spirit of my invention; hence I do not wish to be understood as limiting myself to the exact form, construction, arrangement and combination of parts herein shown and described, or uses mentioned.

What I claim as new and desire to secure by leters patent is:

1. A ceiling suspension grid system comprising a plurality of runners disposed in generally parallel relation, and a plurality of cross runners extending transversely to said first-mentioned runners and connected thereto, said runners having their ends identically formed for engagement with an interlocking means associated with adjacent cooperable runners.

2. A grid system as defined in claim 1, wherein the end of each runner is interlocked to an intermediate portion of the adjacent runner extending transversely thereto.

3. A grid system as defined in claim 1, wherein each end of said runners is provided with a longitudinally extending tongue adapted to be inserted through slotted means associated with the adjacent transverse runner.

4. A grid system as delined in claim 3, wherein said slotted means comprises an intermediate portion of such adjacent transverse runner.

5. A grid system as dened in claim 3, wherein said slotted means comprises a slotted coupling member through which the tongue extends.

6. A grid system as defined in claim 5, wherein said runners are proivded at their upper edge with a longitudinally extending bead, said coupling member comprising a plate having a tongue-receiving slot therein and constructed at its upper edge with channel means adapted to receive the beads of a pair of aligned runners having L-shaped tongue portions positioned in said slot, the tongues of two aligned runners, extending transversely to said coupling member extending through said slot, and a locking element having portions extending through the slots of the respective runners.

7. A grid system as dened in claim 5, wherein said runners are provided at their upper edge with a longitudinally extending bead, said coupling member being constructed at its upper edge with channel means adapted to receive the beads of a pair of aligned runners having their slotted tongues in overlapping relation, said coupling member having a projection constructed to extend through the slots in such overlapping tongues to lock the same in assembled relation.

8. A grid system as defined in claim 3, wherein said tongues are each provided with an elongated, longitudinally extending slot therein adapted to receive locking means for preventing removal of the tongue from said slotted means.

9. A grid system as defined in claim 3, wherein said tongues are each provided with relatively resilient latch means operable, upon insertion through the slotted means to interlock therewith.

10. A ceiling suspension grid system comprising a plurality of runners, each identically formed at its ends for engagement with an intermediate portion of a transversely extending runner of identical construction, said runners being disposed with each runner having its ends in operative engagement with the intermediate portions of adjacent runners extending transversely thereto.

11. A re resistant suspended ceiling grid system comprising a plurality of interlocked, longitudinally and transversely extending runners, each formed at its ends for operative connection to a cooperable runner of said plurality of runners, ceiling panels extending between and supported by said runners, an end portion of each runner `being constructed to have less resistance to deformation than the intermediate portions of said runners, said portions being deformable under expansion stresses in the grid system to reduce buckling and rupture of the ceiling upon the application of heat thereto.

12. A fire resistant suspended ceiling grid system comprising a plurality of interlocked, longitudinally and transversely extending runners, each similarly formed at its ends for operative connection to a cooperable runner of said pluralityr of runners, ceiling panels extending between and supported by said runners, portions of said runners being constructed to have less resistance to deformation than the other portions of said runners, said portions being deformable under expansion stresses in the grid system to reduce buckling and rupture of the ceiling upon the application of heat thereto.

13. A grid system as defined in claim 12, wherein said deformable portions are located at the ends of the respective runners.

14. A grid system as defined in claim 13, wherein said deformable portions are formed by a cap member.

15. A grid system as defined in claim 12, wherein said deformable portions are disposed continuously along the runners.

16. A grid system as defined in claim 15, wherein said deformable portions are formed by a cap member.

17. A runner for ceiling suspension systems adapted to support a plurality of ceiling panels comprising an elongated strip of metal having a vertically extended stem portion providing means for receiving elements from which the runner may be suspended, and a laterally extending portion at the lower edge of the stem portion constructed to receive and support an edge portion of the ceiling panels to be supported, said stern portion having at least one runner-connecting slot in the intermediate portion thereof and a longitudinally extending tongue at each end thereof, each tongue having an elongated slot therein which is closed at each end thereof, said tongues being of a length to enter a runner-connecting slot in an intermediate portion of the stern portion of a like runner disposed transversely thereto, with the outer end of the tongue, and the slot therein disposed at the opposite side of such a slotted stern portion, and providing means for the reception of locking means for interlocking the assembled runners, at least one Vof said tongues and the slot therein being of a length to permit thermal expansion of the stem portion without restricting engagement with the stem portion of such like runner.

18. A runner for ceiling suspension systems adapted to support a plurality of ceiling panels comprising an elongated strip of metal having a vertically extended stem portion providing means for receiving elements from 12 which the runner may be suspended, and a laterally extending portion at the lower edge of the stem portion constructed to receive and support an edge portion of the ceiling panels to be supported, said stem portion having at least one runner-connecting slot in the inter? mediate portion thereof and a longitudinally extending tongue at each end thereof, each tongue having an elon gated slot therein, said tongues being of a length to enter.

a runner-connecting slot in an intermediate portion of the stem portion of a like runner disposed transversely thereto, with the outer end of the tongue, and the slot' therein disposed at the opposite side of such a slotted stem portion, at least one of said tongues and the slot therein being of a length to permit thermal expansion of the stem portion without restricting engagement with the f stem portion of such a like runner.

19. A runner as defined in claim 18, wherein said.

runner is provided with at least one part of the laterally extending panel-supporting portion of the runner and constructed to have less resistance to deformation than other portions thereof, said part being deformable under expan sion stresses thereon to at least partially compensate for such expansion.

20. A runner as defined in claim 19, wherein said` deformable portions are located at the ends of the run-v ner.

21. A runner as defined in claim 20, wherein said runner is formed from a single stripof metal and said deformable portions are formed by reducing the structural strength of such portions.

22. A runner as defined in claim 19, wherein said deformable portions are formed by a cap member carried by the stem portion. Y

23. A runner as defined in claim 22, wherein said stem portion comprises two plies of material connected at their upper edges, each being provided at its lower edge with i an outwardly extending flange, said flanges being disposed in a common plane, said cap member having reverselyy bent longitudinal edges forming channels for the reception of said flanges, the combined width of the respective 1 flanges being less than the width of said cap member,

said flanges being constructed to permit deformation of the cap member, under transversely applied stresses,in a

direction toward said stem.

24. A runner as defined in claim 18, wherein said tongues are each provided with relatively resilient latch means.

References Cited by the Examiner RICHARD W. COOKE, JR., Primary Examiner.

EARL C. DARSCH, HENRY C. SUTHERLAND,

Examiners.-

JACOB L. NACKENOFF, FRANK L. ABBOTT, M. I,

MINSK, J. L. RIDGILL, Assistant Examiners,