Patent Application
20060260246
The invention relates to suspended ceiling grid and more particularly, to improvements in splice connections for main runners for such systems.
Suspended ceiling grid customarily comprises main runners and cross runners that intersect the main runners. The main runners are produced in fixed lengths, typically in 12 foot lengths, and are spliced end-to-end to extend across a room. For connecting their ends, current grid tee or runner products commonly utilize an integral splice or connector cut and formed from the grid runner web material. The splice uses a lanced pocket pushed out from the vertical web plane in one direction and a protruding stiffened tongue with a locking detent pushed out in the opposite direction. Upon installation, the tongue of each runner or tee inserts into an opposing pocket making a double lock. When all of the physical features of the splice are formed in the ideal or desired configuration and location, the tees interlock with a light predictable insertion pressure, aligned both vertically and horizontally with each other. The resultant connection adequately resists pull-apart forces. The geometry of various physical features, however, tends to vary positionally with variations or change in material thickness of the tee material requiring repeated tooling adjustments as necessary to achieve acceptable part function. Complaints of hard splice assembly and face misalignment are the result of compromise in ordinary variation in the supply of material, tool wear, and sometimes a lack of constant vigilance at the point of manufacture.
The invention provides a splice connection for main runners or tees comprising an end assembly with a uniquely formed pocket made in a cavity between the central web of the runner and a separate spring steel clip attached to the web to align and interlock with an identical opposed end assembly. The result is an in-line connection for main runners or tees. Because the disclosed pocket is formed by the cavity created between an embossed recess on one side of the tee web and an inside clip surface, the pocket can be made with a fixed width, regardless of variations in material thickness of the tee itself. The disclosed concept enables a connection to exhibit consistent insertion pressure as a result of the fixed geometry of the tee cavity and the resilient nature of the clip and web assembly.
The disclosed clip is configured to connect directly with an identical clip so that a reliable high strength joint is produced independent of any variation in the properties of the material of the tee. The clip and pocket are configured to initially self-align the ends of the runners being joined and, when finally connected, to accurately register the butted ends of the runners.
A main runner or grid tee 10 is assembled at each of its longitudinal ends with a connector clip 11. The illustrated grid tees 10 are generally conventional in construction having a lower flange 12, a web 13 extending vertically upwardly from the center of the flange, and a hollow reinforcing bulb 14 at the upper edge of the web. In a conventional manner, the tee 10 can be made by roll forming continuous strips of mild steel sheet stock so that the bulb 14 has a single wall and the web 13 is formed by two layers of sheet stock and the flange 12 has two portions 16. The flange portions 16 are retained together and concealed from a view below by a cap strip 17 of sheet metal, as is conventional. The roll formed stock is cut into tees of predetermined length, for example, nominally 12 feet. The opposite ends of the tees are cut so that its edges 18 at the flange 12 are perpendicular to the longitudinal direction of the tee and the edges of the web 13 and bulb 14 can be formed in a plane tilted slightly rearwardly (e.g. 1 to 3 degrees) away from a vertical plane through the flange edge 18. This slight rearward tilt assures that upon assembly with a mating tee, the respective flange edges 18 will form a tight butt joint for a good appearance. When describing the tees 10 and clips 11 herein, the forward direction is a direction away from the center of a tee and, when reference is made to a standard tee, the flanges 12 are, as mentioned, at the lower edge of the vertical web consistent with the orientation of the tee in a normal installed condition.
Each end of a tee 10 has-its web 13 pierced with a notch 21 open at an edge 22 of the web. Rearward of the web edge 22, a portion of the web 13 is formed or stamped with a lateral offset or embossment 23 that includes a cantilever tab 24. The tab 24 is free of connection with surrounding areas of the web in a zone forward of its connection with the remainder of the embossment 23. Apart from the embossment 23, including the tab 24, the material of the web 13 surrounding the notch 21 remains in the original plane of the web 13. Lower and upper edges 26, 27 of the notch 21 are spaced from the flange portion 16 and bulb 14 a substantial distance preferably, for example, a distance at least several times the thickness of the stock forming the tee thereby enabling the tooling that creates the notch to be robust in this area for long tool life. Two holes 28 are punched through the web 13 to receive parts of the clip 11 for their permanent assembly as described below.
The clip 11 is stamped from sheet metal stock preferably in strip form processed in progressive dies or tooling in which various features or formations are made on the clip body. The clip 11, preferably, is formed of a high strength spring steel such as Martinsite −130 having a thickness by way of example of 0.020 inch. The clip material is thus substantially harder than the mild steel material of the tee 10.
The clip 11 has an elongated form with an inner face 31 adapted to abut the web 13 and an opposite outer face 32. The clip 11 includes stiffening or reinforcing flanges 33, 34 at its top and bottom edges projecting outwardly from the outer face 32. The clip 11 is lanced and formed at two locations 36 to form integral projections 37 that after being inserted in corresponding holes 28 in the tee web 13 are staked or clinched in the manner of a rivet to permanently assemble the clip 11 to the grid tee 10. The areas of the clip 11 surrounding the projections 37 is planar and, for reference purposes can be considered to be the plane of the clip body or clip proper. Apart from the projections 37, the clip 11 is bilaterally symmetrical about a longitudinal medial plane.
A central major polygonal or chevron-shaped hole 39 through the clip 11 has at its upper and lower regions, a pair of opposed flanges 41 bent out of the plane of the clip. The flanges or tabs 41 as seen in
The lead edge portions 56, 57 extend to horizontal edges 59 spaced a predetermined distance from one another. Rearward of the horizontal edges 59, are inclined surfaces 61, 62 formed by extensions of the clip flanges 33, 34.
The body of the clip 11 forward of the major hole 39 between horizontal bend lines indicated at 63, 64, extended from the edge portions 59 and surrounding the projections 52 and 48 and recess or depression 47, is planar and bent slightly laterally, from the plane of the clip body rearward of the major hole 39, to the side to which the projection 48 extends (
The geometry of the clip 11 and formations on the end of the tee 10 are arranged to connect with an identical clip, or a similar clip, and a tee end with features described above in the manner of a handshake. Therefore, as is customary, the tee 10 has identical or essentially the same clips on each of its ends. Tees are connected end-to-end by roughly aligning them end-to-end and pushing their clips into the pockets 66 formed between the inside of the web embossment 23 and the related clip 11 of the opposed tee end. The initial alignment need not be perfect since the tapered nose of the connector formed by the surfaces 56, 57 and 61, 62 is adapted to guide or cam the clips into vertical alignment. Lateral alignment is initially accomplished by simply abutting the clips laterally or side-by-side. If the clip 11 of the tee being installed is simply laid onto the top of the flange portion 16 of the previously installed tee, with the clip abutting the correct side of the clip on the previously installed tee, the lower inclined edges or surfaces 56, 61 of the clip being installed will cam the clip vertically upward when it is pushed longitudinally against the opposing tee. This camming action is depicted in
The clips 11 can be precisely formed from a sheet metal strip since the stock can be held to exacting thickness tolerances while being reasonably economical due to its relatively small size compared to the volume of material comprising the grid tee proper. The pocket 66 formed between the embossment 23 including the tab 24 and the inside surface of the clip 10 does not vary in width despite regularly experienced variations in the thickness of the tee material stock. Variation in the width of the pocket 66 is avoided because the tab 24 and associated embossment 23 can be readily stamped by tooling with a lateral offset from the plane of the tee web by a fixed predetermined amount regardless of the thickness of the tee material stock. Consistent lateral sizing of the pocket 66 ensures that only a low consistent force is required to establish a full connection between a pair of tees. The connection between abutted tees is quite strong, because the locking surfaces are part of the clips and, therefore, have very high yield strength. With a pair of clips 11 coupled to one another their respective round holes 44 are in alignment and a screw or other fastener can be inserted through these holes where an exceptionally strong joint is required.
A coupled pair of grid tees can be conveniently disconnected without tools by simply twisting one of the coupled tees about its longitudinal axis. This twisting action results in resilient deflection of the tabs 24, embossments 23 and clips to a degree sufficient to enable the locking edges 51 to move laterally out of engagement with the receiving edge 42 of the main hole 39 of the opposing clip to thereby release their locking engagement. This resilient deflection is permitted by the geometry of the related embossment and tab on the web and the absence of direct affixing of the clip to the web forward of the locking edge of the major hole in the web.
The flat angled portion of the clip between the lines 63, 64 at the forward end of the clip that is angled relative to the plane of the clip at the rear acts when connected to another clip to “sandwich” or force the tee web above and below the notched forward web area into planar alignment with another connected tee regardless of the tee material thickness.
It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.
