Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: SOUND ATTENUATING METAL FRAMING MEMBER
FIELD OF THE INVENTION
The present invention relates to metal framing members
for use in constructing partition walls. In particular,
the invention relates to metal framing members which
provide for reduced sound transmission through the
partition walls.
BACKGROUND OF THE INVENTION
It is common practice in residential and many commercial
buildings to separate the various rooms by partition
walls to define the space of the room. Such partition
walls have in the past been constructed of wood members
including top and bottom plates and bridging studs. The
use of wood members has its short comings. The supply of
lumber is getting scarce and costs have increased during
recent years. In addition, wood can warp and go out of
shape when it becomes wet as well as being susceptible to
fire damage and attack by vermin of various kinds.
In recent years,-partition walls framed with sheet metal
members have been employed. The use of sheet metal
members provides advantages of dimensional stability,
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ease of manufacturing, and conservation of natural
resources, among others. However, metal studs are better
conductors of sound then wood and additional measures
must be taken to reduce sound transmission through walls.
In partition walls separating units in a multi-unit
building, techniques have been developed to reduce the
sound transmission through a metal framed partition wall.
For example, in some circumstances furring members are
installed across the studs of the partition wall and the
covering material is attached to this furring member.
Another commonly employed technique is the use of double
or triple layers of wall board as the covering material
for the partition wall, However, both of these
techniques increase the cost and time to frame and
install the partition walls.
There thus remains a need for metal framing members which
can reduce the sound transmission without the use of
additional measures.
SUMMARY OF THE INVENTION
The present invention provides for a metal framing member
having improved sound attenuating properties to reduce
the sound transmission through a partition wall
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constructed utilizing the framing members. The framing
members have a central web which bridges the interior of
a partition wall, attached to either edge of the central
web are upstanding side walls to which the covering
material may be attached. The central web is provided a
plurality of paired rows of elongated slits oriented
along the longitudinal direction of the central web. The
individual rows of slits in the paired rows are offset
from one another in the longitudinal direction such that
there is no uninterrupted line of metal bridging the web
from one edge of the web to the other in any transverse
direction.
In an aspect of the invention, the central web is
provided with two paired rows of elongated slits, each of
the paired rows being adjacent to each of the upstanding
side walls.
In a further aspect of the present invention, the slit
are longer in the longitudinal direction of the metal
stud than the material of the web of the stud between
adjacent longitudinally aligned slits.
In yet another aspect of the invention, the slits are at
least four times as long as the material between the
adjacent longitudinally aligned slits.
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In yet another aspect of the invention the central web of
the framing member is provided with a main central
section bordered by channel shaped ribs adjacent the
upstanding side wall. The channel shaped ribs extending
longitudinally of the stud. Two paired rows of elongated
slits are provided in the main central section of the
central web adjacent to each of the longitudinally
extending channel shaped ribs.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention are
illustrated in the attached drawings in which:
Figure 1 is a perspective view of a partition wall
constructed utilizing a preferred embodiment of the metal
framing members of the present invention;
Figure 2 is a perspective view of a first preferred
embodiment of a metal stud of the present invention;
Figure 3 is an end view of the metal stud of Figure 2;
Figure 4 is a side view in cross section of the metal
stud of Figure 2; and
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Figure 5 is an end view in cross section of the metal
stud of Figure 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is directed to a metal framing
member such as studs 10 and tracks 12 utilized in framing
partition walls 14 as illustrated in Figure 1. The
partition walls 14 are framed from a metal track 12
forming the top plates 12a and bottom plates 12b that are
bridged by the parallel spaced apart metal studs 10. The
spacing between the metal studs 10 is that typically
utilized in construction of walls generally at 16 inches
on center although other spacing such as 24 inches on
center may be utilized. The studs 10 are attached to the
top plate 12a and bottom plate 12b through the use of
suitable screws 16. Once the partition wall 14 is framed
utilizing the studs 10, top plate 12a and bottom plate
12b, suitable wall covering material such as wall board
IS is attached to the partition wall utilizing suitable
screws 20.
As illustrated in particular in Figures 2 to 5, the metal
stud 10 has a generally C-shaped rectangular cross
section with two parallel spaced apart side walls 22 and
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a central web 24 bridging the side walls 22. The side
walls 22 terminate in inwardly turned ledges 26. The
central web 24 may be provided with a main central
section 24a bordered by channel shaped ribs 24b extending
longitudinally of the stud 10. The longitudinal ribs 24b
extend outwardly of the stud 10 and aid in stiffening of
the central web of the stud 10.
The main central section 24a of the web 24 is provided
with a plurality of longitudinally extending paired rows
of slits 30 which provide the sound attenuating
characteristic of the metal framing members of the
present invention. As illustrated in the figures,
preferably two rows of paired slits 30 are provided
adjacent each of the channel shaped ribs 24b in the main
central section 24a of the central web 24. In framing
member not having the channel shaped ribs, it is
preferred if the paired rows of slits are provided in the
web adjacent each of the upstanding side walls.
The individual rows of slits 30 of the paired rows on
each side of the web 24 are offset from one another such
that the section of the web 24a between adjacent
individual slits 32 is aligned with the central region of
the slit 32 in the adjacent row. In this way, there is
no continuous unbroken line of metal in any transverse
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direction from one edge of the central web 24 to the
other. Thus, there is no direct line by which sound may
be directly transmitted across the web of the metal stud
10.
In addition, the slits 32 are significantly longer in the
longitudinal direction of the metal stud than the
material 34 of the web of the stud bridging between
adjacent slits 32. Preferably the slits 32 are at least
four times as long as the material 34 bridging between
the adjacent slits 32. More preferably, the slits 32 are
about 2 to 4 inches long and the material of the web 34
between the adjacent slits 32 is about 4 inch to 1 inch
long. Most preferably, the slits 32 are about two inches
long and the material 34 between the adjacent slits 32 is
about 14 inch to 4 inch. This also provides for a reduced
amount of material through which the sound can transverse
the web 24 of the stud 10. By providing the slits 32 as
illustrated, the amount of material through which sound
can be transmitted across the stud 10 is reduced
significantly further aiding in the sound attenuating
properties of the metal framing members of the present
invention.
As illustrated in the drawings, it is preferred that as
the slits 32 are being formed the slits 32 are displaced
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out of the plane of the web 24 of the metal stud 10.
This provides for an air gap 36 between the edge of the
slit 32 and the edge of the web 24 of the metal stud 10
further aiding in the sound attenuating properties of the
metal framing members of the present invention.
As illustrated in the figures, it is preferred that it in
addition to the sound attenuating structures in the metal
stud as described that similar structures are also
provided in the track 12 forming the top and bottom
plates of the metal stud wall.
The sound transmission class (stc) of the stud of the
present invention was compared to a standard metal stud
in tests conducted utilizing the ASTM standard testing
procedure. Walls were constructed utilizing either the
metal stud and track of the present invention or a
standard metal stud and track. One series of walls had a
single layer of drywall applied to each side while
another series had a single layer of drywall on one side
and a double layer of drywall on the other. The results
of the test are shown in Table 1.
TABLE 1
SINGLE LAYER OF SINGLE LAYER ON ONE
WALLBOARD ON EACH SIDE SIDE, DOUBLE LAYER
ON OTHER SIDE
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PRIOR ART METAL 44 dB 48 dB
STUDS
STUDS OF PRESENT 49 dB 54 dB
INVENTION
As can be seen from the results of Table 1, the stud of
the present invention provides for an improvement of 5 to
6 dB of sound reduction compared to a standard metal
stud. This would result in a clearly noticeable
reduction in sound transmission with walls constructed
with the stud of the present invention as compared to
those constructed with the standard metal studs.
The sound attenuating metal framing members of the
present invention provide for increased sound attenuating
properties compared to a normal metal stud or track, thus
greatly enhancing the sound attenuating property of
partition walls framed utilizing the framing members of
the present invention. This can result in reduced
construction costs as additional structures such as
additional layers of wall board or furring member may not
be required. Alternatively, should additional layers of
wall board be installed, sound attenuating properties of
a metal partition wall framed with the framing members of
the present invention would be enhanced compared to a
similar wall arrangement utilizing the prior art studs.
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While in the preferred embodiments illustrated, a
plurality of rows of slits are illustrated it would be
appreciated by those skilled in the art that other
arrangements may also be possible without departing from
S the spirit of the invention.
