TECHNICAL FIELD

[0001] The present invention relates generally to ceiling systems, and more particularly to ceiling beam connectors which aid the performance of the ceiling system in the event of a fire.

BACKGROUND OF THE INVENTION

[0002] A typical suspended ceiling includes a plurality of main beams which extend parallel to one another and cross beams which span the distance between adjacent main beams. The cross beams interlock with the main beams via connectors which are inserted through slots in the main beams. The ceiling grid formed by the plurality of main beams and the plurality of cross beams is typically hung from a structural ceiling by hang wires, and ceiling panels are laid in the rectangular openings formed by the main beams and the cross beams. The panels are generally highly heat resistant and help protect the structural ceiling from heat damage in the event of a fire.

[0003] Fire, however, can cause damage to the main beams and cross beams which weakens the suspended ceiling. For example, the elevated temperatures cause the beams to expand longitudinally to relieve stress. If the beams are not allowed to expand, they will buckle, causing the panels to fall from the openings and exposing the structural ceiling to the heat of the fire.

[0004] The main beams are generally kept relatively intact during a fire by providing cutouts along the beam which permit the beam, in a controlled way, to collapse in-line, longitudinally, from the forces of compression created by the fire. Such an arrangement is disclosed, for example, in U.S. Patent No. 4,606, 166. In the cross beams, however, such cutouts are generally not used, since they unduly weaken the beams relative to the length of the spans, and the relatively large controlled collapse is not required because the degree of expansion is not as large. For example, the expansion created by a fire is about 0.1 inches per foot of beam length, so that in a five foot cross beam, the maximum expansion may be less about 0.5 inches.

[0005] Accordingly, there remains a need for providing suitable expansion relief in cross beams.

BRIEF DESCRIPTION OF THE DRAWING

[0006] The invention is best understood from the following detailed description when read in connection with the accompanying drawing. It is emphasized that, according to common practice, the various features of the drawing are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawing are the following figures:

[0007] FIG. 1 A is a side view of a connector clip, according to an embodiment of the present invention;

[0008] FIG. I B is a profile view of a connector clip, according to an embodiment of the present invention;

[0009] FIG. 2A is a profile view of a connector clip attached to a ceiling cross beam, according to an embodiment of the present invention;

[0010] FIG. 2B is another profile view of a connector clip attached to a ceiling cross beam, according to an embodiment of the present invention;

[0011] FIG. 3 is a profile view of a ceiling main beam including a keyhole slot, according to an embodiment of the present invention;

[0012] FIG. 4A is a side view of a connector clip attached to a ceiling cross beam and inserted into a keyhole slot in a ceiling main beam, according to an embodiment of the present invention; and [0013] FIG. 4B is an end view of a connector clip attached to a ceiling cross beam and inserted into a keyhole slot in a ceiling main beam, according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0014] Referring now to the drawing, in which like reference numbers refer to like elements throughout the various figures that comprise the drawing, embodiments of the present invention include connector clips for attaching cross beams to main beams in a suspended ceiling. The connector clips provide for suitable expansion relief in the cross beams in the event of a fire.

[0015] Referring to FIGS. 1 A- I B, a connector clip 100 is provided according to an embodiment of the present invention. The connector clip includes a trailing portion 110 and a leading portion 120. The trailing portion 110 and the leading portion 120 are attached by an offset 106. As used herein, "attached" means either two distinct pieces joined by a suitable fastening element or a single unitary piece. Typically, the connector clip 100 are made of a single unitary piece of stamped metal, for example aluminum or steel.

[0016] The trailing portion 110 includes a plurality of fastening holes 112 and a stiffening bump 114. As described below, the plurality of fastening holes 112 may be used to secure the connector clip 100 to a ceiling beam. The stiffening bump 114 extends laterally from the trailing portion 110 in the opposite direction from the offset 106. The stiffening bump 114 may be stamped from (but still fully connected to) the trailing portion 110 such that the stiffening bump 114 is hollow. The stiffening bump 114 may have any suitable shape and size which will allow the trailing portion 110 to resist twisting or bending. The trailing portion 110 may further include two rear tabs 116. The rear tabs 116 do not impact the functioning of the connector clip 110, but allow multiple connector clips 110 to be manufactured in strips (not shown) with the rear tabs 116 of one connector clip 110 attached to the leading portion 120 of an adjacent connector clip 110. One connector clip 110 may be easily removed from the strip by cutting the leading portion 120 from the rear tabs 116.

[0017] The leading portion 120 includes an anti-rotation bump 122 laterally extending in the direction of the offset 106, a top protrusion 124 which is bent toward the offset 106, and a locking tab 126 laterally extending in the direction of the offset 106 punched out from the leading portion 120. The leading portion 120 further includes a hook 128 on the bottom edge (i.e., the edge opposite the top protrusion 124) of the leading portion 120. The anti-rotation bump 122 may have any suitable shape and size which will allow the leading portion 120 to fill up to half of the width of a slot in a main beam, as described in more detail below. The hook 128, the top protrusion 124, and the stiffening bump 122 are vertically aligned (i.e., a vertical line will pass through each of the hook 128, the top protrusion 124, and the stiffening bump 122). The locking tab 126 is slightly offset from the top protrusion 124 away from the offset 106.

[0018] The connector clip 100 further includes a top angled flange 130 and a bottom angled flange 140 which are each bent away from the direction of the offset 106. The top bent portion 130 includes a finger 132 which extends above the leading portion 120 and is separated from the leading portion 120 by a notch 134. The notch 134 may include a bulb portion 136 which extends into the trailing portion 110. The finger 132 is thinnest at the bulb portion 136, and accordingly will bend most readily at the bulb portion 136.

[0019] Referring to FIG. 2, the connector clip 100 may be connected to a cross beam 200. The cross beam 200 includes vertical web 210 extending between a bulb 220 at the top end of the web 210 and flanges 230 at the bottom end of the web 210. The trailing portion 110 is attached to the web 210 of the cross beam 200 by any suitable fastening elements 150, for example rivets or clinch joints which extend through the fastening holes 112 and through the web 210. The leading portion 120 extends beyond the edge of the web 210 and, because of the offset 106, is aligned with the web 210. The top angled flange 130 is adjacent to the bulb 220 and the bottom angled flange 140 is adjacent to the flanges 230. The top angled flange 130, the bottom angled flange 140 and the stiffening bump 114 reinforce the trailing portion 110 and prevent undesired bending of the trailing portion 110 when connected to the cross beam 200.

[0020] Referring to FIG. 3, a main beam 300 is provided for use in conjunction with the connector clip 100 and the cross beam 200 described above. Like the cross beam 200, the main beam 300 includes a vertical web 310 extending between a bulb 320 at a top end of the web 310 and flanges 330 at the bottom end of the web 310. The main beam 300 further includes a keyhole slot 340 with includes a bottom edge 342, a top edge 344, and sides 346 extending between the bottom edge 342 and the top edge 344. The width of the keyhole slot 340 (i.e., the distance between the sides 346) will vary along the height of the keyhole slot 340 (i.e., measured between the bottom edge 342 and the top edge 344), with the narrowest portion of the keyhole slot occurring at a narrowed region 348 nearer to the top edge of the keyhole slot 340 than the bottom edge of the keyhole slot 340.

[0021] Referring to FIG. 4, the cross beam 200 having the connector clip 100 attached to the web 210 may be connected to the main beam 300 by inserting the leading portion 120 of the connector clip 100 through the keyhole slot 340. The lower edge of the connector clip 100 is inserted into the keyhole slot 340 first and the connector clip 100 is rotated to bring the hook 128 into contact with the bottom edge 342 of the keyhole slot 340. As the connector clip 100 is rotated into position, the top protrusion 124 will contact the top edge 344 of the keyhole slot 340. Continued rotation will force the connector clip 100 downward, resulting in the top protrusion 124 pushing through the keyhole slot 340 and the hook 128 contacting the bottom edge 342 of the keyhole slot 340. The top protrusion 124 pushing through the keyhole slot 340 produces an audible click which signals that the connector clip 100 is secured in place. Once secured, the locking tab 126 will be aligned with the narrow portion 348 of the keyhole slot 340, prevent the connector clip 100 from backing out of the keyhole slot 340. Accordingly, the cross beam 200 may be cantilevered in the keyhole slot 340 during installation without requiring a connection from the opposing side of the key hole slot 340. The top protrusion 124 and the anti- rotation bump 122 are positioned inside the keyhole slot 340 to limit rotation of the connector clip 100 inside the keyhole slot 340 about an axis parallel to the length of the cross beam 200 without substantially increasing the overall thickness of the connector clip 100. To allow a second connector clip 200 (not shown) to be inserted into the keyhole slot 340 from the opposite side of the main beam 300, the top protrusion 124 and the anti-rotation bump 122 should extend laterally from the leading portion 120 at a distance equal to no more than half of the width of the keyhole slot 340 outside the narrowed portion 348. The distance between the hook 128 and the top protrusion 124 is approximately equal to the height of the keyhole slot 124. Accordingly, vertical movement of the connector clip 100 in the keyhole slot 340 is constrained and the possibility of the connector clip 100 accidentally being removed from the keyhole slot 340 during installation is reduced. Lateral movement of the connector clip 100 is constrained by the hook 128 and the locking tab 126. Because the movement of the connector clip 100 is constrained within the keyhole slot 340, the cross beam 100 self- aligns with the main beam 300, eliminating the need for careful positioning of the cross beam 100.

[0022] Once the connector clip 100 is secured into the keyhole slot 340, the cross beam 200 is connected to the main beam 300. The flanges 230 of the cross beam 200 substantially abut the flanges 330 of the main beam 300, creating a continuous visual appearance when the suspended ceiling is viewed from below. A portion 222 is removed from the bulb 220 of the cross beam 200 to create a gap between the bulb 220 of the cross beam 200 and the bulb 320 of the cross beam 300. Despite no bulb-to-bulb connection, vertical, upward rotation of the cross beam 200 is constrained by the finger 132, which is adjacent to, but separated from, the web 310 of the main beam 300 by a small gap. The small gap between the web 310 and the finger 132 allows for a small degree of vertical upward rotation of the cross beam 200, but otherwise provides for a bulb-to-bulb feel under normal conditions (i.e., in the absence of fire-induced expansion of the cross beam 200). [0023] In the event of a fire, heat will cause expansion of the cross beam 200 which forces the connector clip 100 toward the main beam 300. As the connector clip 100 is forced toward the main beam, the finger 132 will bend laterally, allowing for expansion of the cross beam 200. In other words, the finger 132 will constrict movement of the cross beam 200 under normal conditions, but will bend out of the way when excessive stress is applied to the cross beam 200 in the event of a fire.

[0024] In the event the expansion of the cross beam 200 is so great that the cross beam 200 still needs to expand even after the finger 132 is bent out of the way, the connector clip 100 will also bend at the offset 106, allowing the cross beam 200 to move laterally with respect to the main beam 300 while still remaining connected to the cross beam 300. Because of the reinforcement of the leading portion 120 and the trailing portion 110 with the anti-rotation bump 122 and the stiffening bump 114, the connector clip 100 will selectively bend at the offset 106 in a controllable manner. Once the fire is extinguished and the cross beam 200 cools down and contracts, the connection between the cross beam 200 and the main beam 300 will be maintained because the locking tab 126 and the hook 128 hold the connector clip 100 in the keyhole slot 340.

[0025] Certain preferred embodiments of connector clips for attaching cross beams to main beams in a suspended ceiling which provide for suitable expansion relief in the cross beams in the event of a fire have been described herein. It is to be understood that various modifications may be made to these described embodiments without departing from the spirit and scope of the invention. All such modifications and other

embodiments are intended to be within the scope of the above description and in the following claims.