RAIL FOR SUSPENDED CEILING COMPRISING EXPANSION ABSORBERS

Abstract

A novel design of rails for a suspended ceiling, the rails including expansion absorbers. The absorbers are produced so that the rails can absorb an expansion while maintaining the integrity of the ceiling, so that the ceiling panels do not fall in the event of a fire. The rails maintain a significant load-bearing capacity despite the presence of one or more expansion absorbers over the length thereof.

Claims

1. A rail for a panel support forming a suspended ceiling, said rail having an inverted T-shaped cross section and having a height Ht, the rail comprising: a vertical web extending from a lower end to an upper end, horizontal extensions forming a base plate, which is adapted to support panels, which horizontal extensions are arranged at the lower end of the vertical web, a bulbous piece arranged at a top of the vertical web, and at least one expansion absorber; said expansion absorber comprising: a main opening comprising two substantially vertical edges extending into the vertical web, the two substantially vertical edges being spaced apart by a length L1 when the rail is not subjected to a longitudinal compressive force, the two substantially vertical edges being aligned so as to abut against one another when the rail is subjected to a sufficient longitudinal compressive force; said main opening extending, at a lower part thereof, as far as an area of material able to form a fold line when the rail is subjected to a longitudinal compressive force; two slits each extending on either side of the main opening over a total length L2 greater than L1, the two slits delimiting, with the base plate, two strips of material which are able to fold, the two substantially vertical edges extending over a height H1 representing between 0.3 and 0.8 times a height Hb of the vertical web.

2. The rail according to claim 1, wherein the two slits comprise a horizontal part and a vertical part.

3. The rail according to claim 1, wherein the two slits extend obliquely from a base of the two substantially vertical edges of the main opening toward the area able to form a fold line.

4. The rail according to claim 1, wherein the main opening extends, at the upper part thereof, to a fine strip of material which is able to deform under the effect of a longitudinal compressive force by forming a bridge.

5. The rail according to claim 4, wherein the strip of material which is able to deform comprises a central notch defining a fold line in an upper part of the bulbous piece.

6. The rail according to claim 1, wherein: the upper part of the bulbous piece comprises a cut-out; the main opening extending, at an upper part thereof, to a segment of intact material present between the main opening and the cut-out of the bulbous piece; each segment of intact material of the bulbous piece being able to deform laterally under the effect of a longitudinal compressive force;

7. The rail according to claim 1, wherein the vertical web comprises an extra thickness which stiffens the two substantially vertical edges of the main opening.

8. The rail according to claim 1, wherein a ratio of the distances L2/L1 is greater than 2.

9. The rail according to claim 6, wherein the segments of material of the bulbous piece which are able to deform have a length L3, a ratio of the distances L2/L3 being between 4 and 9.

10. The rail according to claim 1, wherein L1/Ht is between 0.05 and 0.8.

11. The rail according to claim 1, wherein the two strips of material which are able to fold have a height H2, a ratio H2/Hb being between 0.02 and 0.4.

12. The rail according to claim 1, comprising a plurality of expansion absorbers arranged along its length.

13. The rail according to claim 1, wherein the two substantially vertical edges extend over a height H1 representing between 0.4 and 0.8 times the height Hb of the vertical web.

14. The rail according to claim 8, wherein the ratio of the distances L2/L1 is greater than 4.

15. The rail according to claim 9, wherein the ratio of the distances L2/L3 is between 5 and 8.

16. The rail according to claim 10, wherein Ll/Ht is between 0.1 and 0.5.

17. The rail according to claim 11, wherein the ratio H2/Hb is between 0.05 and 0.2.

Description

[0038] The invention will now be illustrated with reference to the figures, in which:

[0039] FIG. 1 shows a perspective view of part of a rail comprising an expansion absorber according to a first embodiment;

[0040] FIG. 2 shows the same perspective view when the rail is subjected to a longitudinal compressive force;

[0041] FIG. 3 shows a front view of the non-compressed rail;

[0042] FIG. 4 shows a front view of the rail subjected to a longitudinal compressive force;

[0043] FIG. 5 shows a front view of part of a rail comprising an expansion absorber according to a second embodiment;

[0044] FIG. 6 shows a front view of the same rail as in FIG. 5, subjected to a longitudinal compressive force.

[0045] FIGS. 1 to 4 illustrate a rail 1 according to a first embodiment, the profile of which is an inverted T, comprising a central web 2 arranged vertically. At the lower end thereof, the arms of the T form a base plate 3 able to support ceiling panels (not shown). The upper part of the web has a bulbous piece 4 mounted over it. The profiled elements is produced at the outset from a metal plate or sheet of steel, in a single piece. The web 2 therefore consists of a double thickness of the starting plate.

[0046] An expansion absorber is illustrated in FIGS. 1 and 3. It consists of a main opening 5 made through the two thicknesses of the web 2. It extends, at the upper part thereof, substantially to the lower part of the bulbous piece 4 and, at the lower part thereof, to the base plate 3. The opening 5 comprises two vertical edges 6a and 6b, spaced apart by a distance L1. The opening delineates, at the lower part thereof, a V-shaped notch 7.

[0047] The expansion absorber further comprises two slits made in the two thicknesses of the web 2, on either side of the opening 5. In the example illustrated in FIGS. 1 to 4, the slits have a horizontal part 8a, 8b extending over a total distance L2 and a vertical part 9a and 9b connecting the distal end of the slit to the base plate 3. The remaining distance between the lower end of the vertical slits 9a and 9b and the base plate 3 is of the same order of magnitude as the thickness of the steel sheet constituting the rail.

[0048] The slits delimit, in the web 2, two strips of material 10a and 10b on either side of the notch 7 and above the base plate 3. The slits delimit, at the distal end thereof, a deflection point for the base plate when the rail is subjected to a longitudinal compressive force.

[0049] In a variant embodiment (not shown), the slits may extend obliquely from the main opening 5 to the base plate 3.

[0050] The expansion absorber further comprises a gap 11 in the upper part of the bulbous piece 4, so as to delimit two strips of material 12a and 12b which are able to laterally buckle when the rail is subjected to a longitudinal compressive force.

[0051] FIGS. 2 and 4 illustrate the rail 1 subjected to a longitudinal compressive force. When the absorber is triggered, the base plate 3 and the strips of material 10a and 10b deflect downwardly from the slits 9a and 9b, forming a fold line 13 under the notch 7. At the same time, the strips of material 12a and 12b of the bulbous piece 4 spread apart laterally and the edges 6a and 6b of the opening 5 come together. The strips of material 12a and 12b have a length L3.

[0052] When the two edges 6a and 6b come into contact, at a stage of the deformation of the absorber which is controlled by the spacing between the edges, a resistance to compression appears which makes it possible to block the compression of the first absorber triggered and to transfer the subsequent deformations on to another absorber.

[0053] Without this resistance, when a first absorber of the rail is triggered, it would constitute a weak zone in terms of compression and would absorb the whole deformation of the rail without another absorber in the rail reaching its triggering threshold.

[0054] In order to increase the resistance of the two edges 6a and 6b, it may be envisaged to add an extra thickness 14a, 14b along the edges 6a and 6b.

[0055] FIGS. 3 and 4 depict a front view of the same part of rail 1 provided with an absorber. FIG. 3 depicts the distances L1 between the two edges 6a and 6b and the distance L2 between the distal ends of the horizontal parts 8a and 8b of the slits. The distance L2 defines the length of the base plate which will deflect under the compressive force.

[0056] The distance L3 defines the length of the strips of material 12a and 12b of the bulbous piece 4 which are able to buckle when the rail is subjected to a longitudinal compressive force.

[0057] In order to obtain a good absorption effect while reducing the loss of load-bearing capacity of the rail as much as possible, it is important that the distance L2 is greater than the distance L1. In the example illustrated, L2 is approximately 14 times greater than L1.

[0058] The greater the distances L2 and L3, the lower the triggering threshold of the absorber.

[0059] The distance L1 does not have an effect on the load-bearing capacity. L1 can be determined based on the desired fire resistance and on the number of absorbers arranged on the same rail.

[0060] Unlike the absorbers of the prior art, the slits 8a, 9a and 8b, 9b of the absorber according to the present invention make it possible to maximize the load-bearing capacity of the rail and force the two ends of the rail to be held in an aligned plane during the expansion of the rail.

[0061] In the example illustrated, if there is an expansion absorber every 60 cm, the distances are L1=5 mm, L2=70 mm, L3=10 mm.

[0062] If there is an expansion absorber every 120 cm, the distances are L1=12 mm, L2=70 mm, L3=10 mm.

[0063] Ht is the total height of the profile. Hb is the height of the web. In the example illustrated, Ht is approximately 37 mm and Hb is approximately 25 mm.

[0064] H1 is the height of the part of the vertical edges 6a and 6b located above the slits 8a, 8b. In the example illustrated, H1 is approximately half the height of the web Hb. The larger H1 is, the more the strength of resistance to compression increases, preventing all the expansion being absorbed by a single absorber.

[0065] H2 is the height of the strips 10a and 10b. In the example illustrated, it is a tenth of Hb.

[0066] H3 is the height of the strips of material 12a and 12b of the bulbous piece 4. In the example illustrated, H3 is eight tenths of the height of the bulbous piece 4 (Ht−Hb).

[0067] FIGS. 5 and 6 illustrate a second embodiment.

[0068] The expansion absorber also consists of a main opening 50 made through the two thicknesses of the web 2. It also extends, at the lower part thereof, to the base plate 3, also delimiting a V-shaped notch 7, but at the upper part thereof, the opening 50 extends substantially to the upper part of the bulbous piece 4, providing only a thin strip of material 20. In order for the strip of material 20 to be able to buckle upward when the rail is subjected to a longitudinal compressive force, it comprises an inverted V-shaped notch 21. This notch 21 thins the strip of material 20 at the central part thereof, to form a fold area 22 which rises when the rail is subjected to a longitudinal compressive force.

[0069] The opening 50 also comprises two vertical edges 60a and 60b, spaced apart by a distance L1.

[0070] According to this second embodiment, the expansion absorber also comprises the same slits 8a, 9a, 8b, 9b as the absorber illustrated in FIGS. 1 to 4.

[0071] The dimensions Ht, Hb, H1, L1, L2 and L3 are substantially the same as for the expansion absorber illustrated in FIGS. 1 to 4.