US 3656577 A
In a ceiling or flooring element of concrete or lightweight concrete the improvement of providing the underside of the element with a box containing a porous sound insulating material to secure sound insulation. The box may be fixed by means of two side-pieces and two flanges put in grooves in the element.
Description (OCR text may contain errors)
United States Patent Larsson et a1.
 CEILING OR FLOORING ELEMENT OF 1151 3,656,577 1 Apr. 18, 1972 2,669,114 2/1954 Mills ..52/599 X LIGHTWEIGHT CONCRETE 2,902,854 9/1959 Greene... ..18l/33.1 3,074,505 l/1963 Schulz "52/144 X [721 Invent Ingmar Lam", Orebm; 3,324,967 6/1967 Robinson ..52/145 x Kumla bmh Sweden 3,498,405 3/1970 Charpentier ..l8l/33.1  Assigneez lntong AB, Hallabrottet, Sweden FOREIGN PATENTS OR APPLICATIONS 6 [221 Med Dec 19 9 65,652 2/1969 Germany 52/145  Appl. No: 881,130 1,172,610 10/1958 France ..52/599 1,027,491 4/1966 Great Britain ..52/144  us. CL 1 1 33 G, 52 145 52 599 115,739 1/1946 Sweden ..52/144  Int.Cl ..E04b1/86 58 Field 61 Search ..181/33.1, 33.1 1, 33; 52/599, Primary Examiner-Robert Ward,
52/144 145 Attorney-Larson, Taylor and Hmds  References Cited [5 ABSTRACT UNITED STATES PATENTS In a ceiling or flooring element of concrete or lightweight concrete the improvement of providing the underside of the 2,916,909 12/1959 Mlllel ..l81/33.1 figment with a box containing a porous sound insulating 1,231,348 1917 material to secure sound insulation. The box may be fixed by 1 1 1 935 9 i 145 means of two side-pieces and two flanges put in grooves in the 2,014,749 9/1935 Smith ..52/144 l m 2,097,892 11/1937 Powell ..181/33.1 2,271,929 2/1942 Venzie ..52/145 3 Claims, 5 Drawing Figures M llillll llll 'lllli l lil lllllllll'hill] PATENTEDAPR 181912 3 656, 577
CEILING R FLOORING ELEMENT 0F LIGHTWEIGHT CONCRETE It is already known not only to provide floorings ceilings or walls of any material with a sound-insulating cladding, made of acoustic plates for instance, but also to give a sound-insulation to floorings or ceilings made of concrete or lightweight concrete by placing layers of some porous sound-insulating material on their undersides. Such insulation, according to a patent granted (Swedish Pat. No. 196 65 l l, is achieved by arranging, on the underside of the ceiling or flooring in question, a layer consisting of flexibly elastic gypsum plates nailed to a wooden framing which plates support a layer of some porous sound-absorbing material, such as mineral wool.
This type of ceiling, however, is rather costly and labourconsuming because the mounting of the components of the same requires much time and the maintaining during that time of spacious scaffolds is obstructing other working moments on the same site.
To avoid the use of scaffolding it has been proposed, alreadey in the factory to give a sound-insulation to the concrete or lightweight concrete elements intended for these ceilings and floorings. This is done by milling out grooves on the undersides of the elements and to put into these grooves porous sound-insulating strips, or foam rubber.
This type or sound-insulation, too, means some undesirable disadvantages inasmuch as the milling of grooves over the whole large surface of a concrete or lightweight concrete element requires rather a costly machinery. Besides, it is difficult to carry out the surface treatment of such concrete or lightweight concrete elements in a satisfactory way.
There is, consequently, great need for instance for a soundinsulating lightweight concrete element, possible to produce in a rational and cheap way and to mount without using building scaffolds.
The present invention relates to a ceiling or flooring element of concrete or lightweight concrete totally eliminating the disadvantages of types earlier known within this technical field. The element according to the invention has a length by many times exceeding its height and width and a width greater than its height.
The invention comprises an element of concrete or lightweight concrete with at least one box adjacant to one of the large surfaces of the element the box having a plane outer plate and two side-pieces for fixing the box in the two long sides of said element, the side-pieces being oriented mainly perpendicularly to said plate and further, in the space between the plane plate, the two side-pieces and the large surface of the element a layer of a porous sound-insulating material.
Referring now to the attached drawing a describtion will be given here below about some possible embodiments of the invention.
FIG. 1 is a fragmentary perspective view of three mounted elements according to the invention, the bearings of the elements having been left out for the sake of clearness.
FIG. 2 4 are vertical cross sections of four different embodiments of the invention.
In FIG. 1 fragments of three lightweight concrete elements 10 are shown which on their undersides are provided with boxes 11. The boxes 11 have sucha length that between their short ends and the short ends of the elements there is formed a bearing area 12 of prescribed width. The elements shown on the figure are joined by tongue and groove."
FIG. 2 shows a vertical cross section of one embodiment of the invention. The box 13 placed on the underside of the element 10 has one plane plate 14 parallel to the underside of the element, two side-pieces l and 16 oriented perpendicularly to the plane plate, and two flanges 17 and 18. The flanges 17 and 18 are intended to support the box 13. To that purpose there are in both the long sides of the element thin grooves 19 and 20 milled out, the length of which shall amount at least to that of the box 13. By means of the flanges the mounting box becomes very simple. It consists in introducing the flange 17 into the groove 19, the plane plate at the same time being kept bent outwards from the underside of the element. After that, the side-piece 16 IS bent outwards from the long side of the element and is brought upwards until the flange springs into the groove 20.
In the plane plate 14 of the box there are holes 21 for letting in the sound to the space 22 formed by the box and the lower large surface of the element.
The space 22 contains a layer 23 of some porous sound-absorbing material, such as mineral wool, woodwool or similar. The thickness of the sound-absorbing layer may vary according to what demands are put on the insulating power. In the example shown, the space 22 is totally filled by the sound-absorbing material the maximum sound-insulation thus being obtained. The holes provided for letting in the sound may suitably occupy at least 10 15 percent of the surface of the plane plate.
The elementshown in FIG. 3 is principally constructed in the same way as the previously described one. The difference is that the box has been given a profile with rounded corners instead of rectangular ones and, further, that the thickness of the sound-absorbing layer 25 is less than the distance between the underside of the element and the plane box plate 26. By placing the layer 25 at some distance from the underside of the element 10 an improved sound-insulation is obtained in relation to the alternative of letting a layer of the same thickness touch the underside of the element.
The element shown in FIG. 4 is provided with a box 27 the comers of which are chamfered by 45.
FIG. 5, finally, shows an element the box 29 of which is shaped like a U-profile without flanges. The box is fixed to the element by nailing, screwing or gluing.
The boxes shown in the figures are firstly intented to be made from plastic laminate, slices of that material being formed to the desired profiles after heating in steam but the invention is not limited to that material. The boxes may, advantageously, be made also of sheet-metal, preferably sheetaluminium or similar.
As will be readily understood from the foregoing describtion the invention involves many important advantages, the greatest one perhaps being the possibility of laying sound-insulating lightweight concrete floorings or ceilings without using scaffolding. Further the total costs as well of the production of the insulation as of its mounting are reduced. Last but not least, floorings and ceilings of an aesthetically appealing shape are obtained.
l. A prefabricated sound absorbing ceiling slab unit, comprising a load-bearing continuous body element of lightweight concrete the length of which by many times exceeds its width and height and the width of which is greater than its height, said element having a lower, planar surface and having, along its sides, grooves and tongues for interconnecting adjacent body elements, a box located under said lower planar surface of said body element and connected to said body element, a layer of sound absorbing material resting upon the bottom of said box, the thickness of said sound absorbing layer being less than the distance between the bottom of said box and the underside of said body element, said bottom of the box having apertures permitting sound waves to penetrate said sound absorbing layer, said box having two upright side-pieces the tops of which are flanged inwardly to provide flanges the sides of said elements including slots milled out in said body element below said grooves and tongues, said flanges engaging in said slots thereby connecting said box to said body element.
2. A prefabricated sound absorbing ceiling element according to claim 1, wherein said apertures engage l0-l5 percent of the surface of the plane plate.
3. A prefabricated sound absorbing ceiling element according to claim 1, wherein said box is made of plate of plastic laminat