Sound absorber

Free-standing sound absorber consisting of an open-cell foam body designed in the manner of a board, having at least one opening in a lateral face for plugging together another, similarly designed foam body. The opening has a height corresponding approximately to half the height of the foam body. The depth of the opening corresponds to the thickness of the foam body.

FIELD OF THE INVENTION 
The invention relates to a sound absorber consisting of an open-cell foam 
body, and more particularly to free-standing sound absorbers. 
BACKGROUND OF THE INVENTION 
Free-standing sound absorbers are generally known in various embodiments. 
The sound absorbers usually have a cubic or cylindrical shape and are 
provided with holding devices for fastening them, for example, to hall 
ceilings. However, the absorption surface is relatively small in 
comparison to the enclosed space and the effectiveness of the individual 
sound absorber is therefore not very satisfactory. 
SUMMARY AND ADVANTAGES OF THE INVENTION 
An object of the invention is to provide an enlarged absorption surface 
relative to the overall size of the sound absorber, and, associated with 
this, to improve sound absorption properties and allow for better adaption 
to a particular application. 
The present invention therefore provides a sound absorber comprising at 
least one open-celled foam body having a height, a width and a thickness, 
the foam body having at least one opening for plugging together with 
another similarly designed foam body; the opening having a height which 
corresponds to approximately half the height of the foam body and a depth 
which corresponds to the thickness of the foam body. 
The foam body is designed in the manner of a board with at least one 
opening in a lateral face. The opening is designed so that it may be 
fitted together with another, similarly designed foam body. The opening 
therefore has a height which corresponds to approximately half the height 
of the foam body and a depth which corresponds to the thickness of the 
foam body. 
An advantage of the invention is that, in comparison with cubic sound 
absorbers with the same dimensions, an enlargement of the absorption 
surface by a factor of 1.5 to 10 results. Thus, the large absorption 
surface allows either more effective sound absorption for the same overall 
size or significantly smaller dimensions of a sound absorber with the same 
effectiveness. 
A further advantage is that with the multi-part plug-together design, large 
free-standing sound absorber units can be transported simply. The 
free-standing sound absorber can be adapted especially well to the 
particular circumstances of the application case by plugging together the 
individual foam bodies. 
A still further advantage is that the dimensioning of the openings permits 
a durable, friction-locking and positive-locking joining of the entire 
free-standing sound absorber after assembly of the individual foam body 
slabs. 
In an advantageous, simple design, the foam body may have a height and 
width which substantially correspond. From this it follows that the 
free-standing sound absorber, formed for example from four foam bodies 
which can be plugged together, has essentially cubic external dimensions 
and therefore can be mounted in any position at its intended location with 
the same effectiveness. 
Two openings which extend parallel to one another and have a corresponding 
design can be provided in the foam body on one side. As a result, matching 
the free-standing sound absorber to a particular application is especially 
simple. Due to the substantial correspondence of height and width and the 
preferably corresponding design of the openings, the individual elements 
from which the free-standing sound absorber is assembled can be connected 
to one another in any form and number. Stocking of individual elements 
also can be simplified in that the individual elements need not differ in 
their dimensions, but rather can consist of foams of mutually differing 
density. It is also advantageous that the free-standing sound absorber may 
be aligned spatially at its intended location to permit simultaneous 
absorption of sound vibrations of different frequency from different 
directions. 
The openings can be provided on the delimiting faces facing one another 
with at least one clearance cut in each case. This design produces a 
simple and problem-free assembly of the plug-together slab bodies made of 
foam. Plugging together takes place by slightly enlarging the opening 
elastically until the two foam bodies are completely plugged together. Due 
to the clearance cut, the use of a lubricant during the assembly is 
unnecessary and compression of the surface of the material of the foam 
body, which may lead to damage, is reliably prevented. 
The clearance cut can have a height which is 0.5 to 0.9, preferably 0.65 to 
0.76, times as large as the height of the opening and a depth which 
corresponds to the thickness of the foam body, the clearance cut being 
delimited in its height on both sides by a shoulder projecting towards the 
opposite delimiting face. To allow easy manufacture, one clearance cut is 
preferably provided on each delimiting face. A number differing therefrom, 
for example two clearance cuts, provides, for a somewhat higher production 
outlay and a minimally more complicated assembly, improved guidance and 
support of the two foam bodies with respect to one another in the 
assembled state of the free-standing sound absorber. The foam bodies are 
held in the region of the projecting shoulders after plugging together. 
For easier assembly and to avoid a clasping of the two foam bodies before 
the joining process is complete, the shoulders can, for example, be 
rounded or be designed in the form of an insertion bevel. 
The foam bodies can be provided with a holding device on at least one of 
their end sides. The holding device on the one hand provides an additional 
joining of the foam bodies fixed on one another and on the other hand 
permits a fastening of the elastically resilient free-standing sound 
absorber to walls or ceilings. 
The free-standing sound absorber is preferably used as a ceiling absorber. 
The ceiling absorber can be suspended vertically or horizontally. When 
fashioned a ceiling absorber, a holding device in each case may be 
provided in the region of the two end sides. The holding devices are, in 
an advantageous development, supported against one another. It is of 
advantage here that the foam bodies are not subject to tensile and 
flexural loading. The holding plates can be provided with hooks and eyes, 
so that a plurality of free-standing sound absorbers can be fastened to 
the ceiling in the form of a chain. The resulting forces are transmitted 
via the holding plates and via the rod system connecting the holding 
plates so that the foam bodies are not subject to loads which reduce 
service life.

DETAILED DESCRIPTION 
FIG. 1 shows a foam body 1 as a slab element which can be attached to a 
plurality of foam bodies of similar design to form a free-standing sound 
absorber. Each foam body 1 has an open-cell structure and is designed in 
the manner of a board. Both openings 3 in this embodiment correspond in 
their shape. The openings 3 penetrate the entire thickness 7 of the foam 
body 1 and have a corresponding depth 6. The height 4 of the openings 3 
corresponds to half the height 5 of the foam body 1. The openings 3 have 
delimiting faces 11 and 12 facing one another. In order to simplify 
assembly of the foam bodies, the openings 3 are provided on each of the 
delimiting faces 11, 12 with a clearance cut 13. By means of this design, 
assembly is simplified, since the surfaces no longer contact one another 
over the entire delimiting face during plugging together. The fixing of 
the foam bodies on one another takes place in this exemplary embodiment 
only via shoulders 16, 17, specifically by friction-locking. The foam body 
1 shown here is intended to be assembled with three further, similarly 
designed foam bodies to form a unit. 
FIG. 2 shows a foam body 1 which is designed in a similar manner to that 
from FIG. 1. The only difference can be seen in the shape of the openings 
3. The shoulders 16, 17 are designed to be sharp-edged and projecting at a 
right angle on the side 18 facing the orifice of the opening 3. On the 
opposite end side 19, the shoulders are beveled in the region of their 
transition to the delimiting faces 11, 12. A different design from this, 
for example a rounded transition, is also conceivable. This design has, 
compared with the shape shown in FIG. 1, the advantage of simplified 
assembly. The foam bodies, which can be plugged into one another, are 
guided into their final position by means of the beveled transition 
between the clearance cut 13 and the delimiting faces 11, 12. Jamming and 
unnecessary adjustment of the foam bodies in their position with respect 
to one another can thereby be prevented during the assembly. In contrast 
to this, the shoulders 16.1, 17.1 starting from the clearance cut 13 have 
a sharp-edged transition into the delimiting faces 11, 12. This design 
produces a barb effect when the plugged-together foam bodies are subject 
to a load counter to the assembly direction. This design therefore 
simplifies handling. 
FIG. 3 shows a free-standing sound absorber consisting of four similar foam 
bodies 1, 2, 21, 22 shown in an assembled state. The slab-shaped foam 
bodies are in each case plugged together in the region of their openings 
3. 
FIG. 4 shows the free-standing sound absorber as a ceiling absorber. The 
slab-shaped foam bodies are plugged together to form a structure according 
to FIG. 3 and fastened by means of holding plates 20 at in each case one 
end side 18, 19 on a ceiling 23 shown diagrammatically. The holding plates 
20 can consist, for example, of light metal and be joined to one another 
by a connecting brace 24. By means of this design, the foam bodies are 
subjected to load only by their intrinsic weight, which is of benefit both 
to their service life and also to their service properties. The holding 
plates 20 are provided with eyes on the side facing the one end side 19 
and with hooks on the opposite end side 18. Due to this design, a 
plurality of free-standing sound absorbers according to the invention can 
be joined to one another. If the ceiling 23 consists, for example, of a 
saddleback roof, with this design the entire roof ridge can be filled with 
the free-standing sound absorbers according to the invention. In FIG. 4, 
two free-standing sound absorbers are fastened to the ceiling 23 in the 
manner of a chain, whereas the free-standing sound absorbers of the 
adjacent chain are arranged staggered with respect thereto. By means of 
this design, overall effectiveness is improved and mutual influencing of 
the free-standing sound absorbers is less.