Note: Descriptions are shown in the official language in which they were submitted.
CA 02505938 2005-05-02
VIBRATION DAMPER
Field of the Invention
The present invention relates generally to noise and vibration
absorption and more particularly, to vibration damper for mitigating noise and
vibration.
Background of the Invention
Unwanted noise and vibration is common in many environments.
Although such noise and vibration can be tolerated in some cases, in many
situations
it cannot thus requiring structures and/or equipment to be isolated from the
sources of
noise and vibration. For example, in many circumstances, noise is generated on
horizontal surfaces such as floors due to various impacts. This noise often
propagates
into surrounding structures creating undesirable noise and vibration
pollution. In
commercial environments, large commercial and industrial machinery and
equipment,
which vibrates during use, often results in impact and/or vibrational noise
passing
through the floor and into adjacent structures. In residential environments,
exercise
equipment such as treadmills, Jacuzzi tubs, whirlpool baths and hot tubs,
which
vibrate during use, result in impact and/or vibrational noise passing into
adjacent
structures. In environments where sensitive measurement or high-tolerance
equipment such as MRI devices and CNC machines is operating, it is necessary
to
isolate such equipment from vibration to ensure accurate and proper operation.
Techniques to dampen noise and vibration have of course been
considered and many different types of vibration mitigating mats and pads to
absorb
vibration exist. For example, U.S. Patent No. 6,796,096 to Heath discloses an
impact
absorbing surface covering for high traffic areas. The impact absorbing
surface
covering includes a shock pad of recycled closed cell foam and an impervious
wear
surface thereon.
U.S. Patent No. 4,002,315 to Van Goubergen discloses a vibration
damper in the form of a stackable mat formed of dampening material.
Projections are
provided on the upper and lower surfaces of the mat.
Also, floating floors to accommodate vibration and/or structure shifts
and settling exist. Unfortunately, to-date these solutions to deal with
unwanted noise
and vibration have proven either to be inadequate, too expensive and/or too
complicated. As will be appreciated, there exists a need for an effective,
simple and
inexpensive noise and vibration dampening device.
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It is therefore an object of the present invention to provide a novel
vibration damper.
Summary of the Invention
Accordingly, in one aspect there is provided a vibration damper
configured to act between equipment that is subject to vibration and an
underlying
floor surface of a building structure, said vibration damper comprising:
a plurality of compressible foam layers secured directly one on top of
the other to form a stack, said stack of foam layers having substantially
planar top and
bottom surfaces and each foam layer having a different density;
a non-compressible load bearing metal plate secured directly to the top
surface of said stack of foam layers, said load bearing plate supporting
equipment that
is subject to vibration;
a resilient mounting pad on said load bearing metal plate; and
a rubber slip resistant layer secured directly to the bottom surface of
said stack of foam layers, said slip resistant layer having a contoured bottom
surface
comprising an array of alternating peaks and valleys and overlying a portion
of the
floor surface on which the vibration damper is disposed, the contour of the
bottom
surface of said slip resistant layer surface and the relative densities of the
foam layers
of said stack being selected such that said vibration damper inhibits
equipment
vibrations from propagating to said floor surface.
In one embodiment, the layer of slip resistant material is formed of
recycled bound rubber product.
The density characteristics of the foam layers are chosen depending on
the nature of the load to be supported by the vibration damper. As loads
increase,
more dense foam material is used.
According to another aspect there is provided a vibration damper
configured to act between equipment that is subject to vibration and an
underlying
floor surface of a building structure, said vibration damper comprising:
a rubber slip resistant layer having a contoured bottom surface
comprising an array of alternating peaks and valleys, said contoured bottom
surface
overlying a portion of the floor surface on which the vibration damper is
disposed;
at least two compressible layers of foam material stacked directly one
on top of the other to form a stack, each layer of foam material having a
different
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density, the density of each layer of foam material being in the range of
120kg/m3 to
1000kg/m3, said stack of foam layers having substantially planar top and
bottom
surfaces and being directly disposed on a surface of said slip resistant layer
opposite
said bottom surface;
a non-compressible load bearing plate disposed directly on said stack
of foam layers and supporting the equipment that is subject to vibration, the
contour
of the bottom surface of said slip resistant layer and the relative densities
of the foam
layers of said vibration dampening structure being selected such that the
vibration
damper inhibits equipment vibrations from propagating to said floor surface;
and
a resilient mounting pad on said load bearing plate.
The vibration damper effectively absorbs noise and vibration, is
inexpensive to manufacture and is easy to install and use. When used beneath
vibrating equipment, the vibration damper virtually eliminates noise and
vibration
from propagating to surrounding structures. When used beneath sensitive
measurement and high-tolerance equipment, the vibration damper effectively
inhibits
vibration generated in the surrounding environment from propogating to the
equipment supported by the vibration damper.
Brief Description of the Drawings
Embodiments will now be described more fully with reference to the
accompanying drawings in which:
Figure 1 is a perspective view taken from above and from the side of a
vibration damper;
Figure 2 is a perspective view taken from below and from the side of
the vibration damper;
Figure 3 is a side elevational view of the vibration damper; and
Figure 4 is a cross-sectional view of the vibration damper taken along
line 4-4 in Figure 1.
Detailed Description of the Embodiments
Turning now to Figures 1 to 4, a vibration damper is shown and is
generally identified by reference numeral 10. Vibration damper 10 is designed
to act
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between a support surface such as an underlying floor surface and residential
or
commercial equipment. Depending on the nature of the equipment to be
supported,
vibration damper 10 acts to inhibit impact and vibrational noise generated by
the
equipment from propogating to surrounding structures and/or to inhibit
vibration in
the surrounding environment from propogating to the equipment.
As can be seen, vibration damper 10 includes a load bearing plate 12
disposed on a vibration dampening structure 14. The vibration dampening
structure
14 in this example includes a slip resistant lower layer 16 and a pair of
intermediate
foam layers 18 and 20 disposed between the lower layer 16 and the load bearing
plate
12.
The bottom surface 22 of the lower layer 16 is contoured to define
peaks 24 and valleys 26 that are sequentially alternated in a three-
dimensional array
giving the bottom surface 22 an "egg-crate" appearance. The depth and pitch of
the
peaks 24 and valleys 26 i.e. its geometry, is selected to give the vibration
damper 10 a
desired dynamic compression characteristic resulting in the vibration damper
10
undergoing a desired amount of compressive deflection under a given dynamic
load.
This dynamic compressive deflection characteristic serves to mitigate transfer
of
structure borne or impact noise. Sharp and long peaks 24 and valleys 26 offer
greater
dynamic compression or deflection under relatively small loads while wide and
short
peaks 24 and valleys 26 result in less dynamic compression or deflection under
relatively larger loads. The contour of the bottom surface 22 also provides
enhanced
slip-resistance thereby to inhibit sliding of the vibration damper 10 relative
to the
support surface on which the vibration damper 10 rests.
The lower layer 16 is formed of recycled bound rubber product.
During the manufacturing process, Styrenebutadiene Rubber (SBR) and natural
rubber are mixed with polyurethane and cured under moderate temperature.
Although
the lower layer 16 typically has a large percentage of SBR rubber therein, the
lower
layer 16 can be made entirely of SBR rubber, other rubbers or a combination
thereof.
Each intermediate foam layer 18, 20 is formed of polyetherurethane
foam and has a different density. Typically the lower foam layer 18 is more
dense
than the upper foam layer 20. The densities of the foam layers are dependent
on the
environment in which the vibration damper 10 is being used. In cases where the
vibration damper 10 is to be subjected to high loads, higher density foam
layers are
used. Generally, the density of the foam layers 18, 20 and the contour of the
bottom
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surface 22 are selected so that for the intended environment, the vibration
damper 10
provides the desired load deflection and vibration insulation while exhibiting
the
desired dynamic and static stiffness. Foam densities in the range from about
120kg/m3 to 1000 kg/m3 have been found to be suitable for most applications.
The load bearing plate 12 is formed of steel and can be powder coated
if desired. A small resilient mount pad 30 formed of polyetherurethane foam
material
is centrally disposed on the load bearing plate 12 to provide a non-slip mount
surface
for the equipment supported by the vibration damper 10.
The lower and intermediate layers 16 to 20 are assembled either
through a lamination machine or through a machine that mechanically or
chemically
bonds the layers together to form the vibration dampening structure 14. Once
the
vibration dampening structure 14 is complete, the load bearing plate 12 and
mount
pad 30 are adhered to or otherwise bonded to the vibration dampening structure
14 to
complete the vibration damper 10.
In use, one or more vibration dampers 10 are placed between the
equipment and support surface on which the equipment rests at appropriate
locations
i.e. under the feet and/or support surfaces of the equipment. The vibration
dampers
are typically not fixed or adhered to the support surface. The peaks 24, which
contact
the support surface, provide an effective non-slip surface even in wet
conditions. The
mount pads 30 on the load bearing plates 12 provide suitable mounts for the
equipment. With the density of the foam layers 18, 20 properly selected in
view of
the particular environment, equipment vibration is effectively absorbed by the
vibration dampers 10 inhibiting the vibration from propogating to surrounding
structures. Also, vibration in the surrounding environment is absorbed by the
vibration dampers 10 thereby to isolate equipment supported on the vibration
dampers
therefrom.
Although the vibration damper 10 is described as including a vibration
dampening structure 14 with three layers 16, 18 and 20, other layer
configurations can
of course be used. For example, the vibration damper 10 can be constructed to
include one or three or more intermediate foam layers. Of course other types
of foam
layers or layers of other suitable material can be used.
The vibration damper may be used in commercial and industrial
applications as well as in residential applications. In commercial and
industrial
environments, the vibration damper 10 may be placed beneath machines and
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equipment such as HVAC compressors, fans, pumps and blowers that vibrate
during
use thereby to inhibit the transfer of machine and equipment vibration to
surrounding
structures. In residential environments, the vibration damper may be used
between
exercise equipment such as treadmills, Jacuzzi tubs, whirlpool baths, hot tubs
etc. to
inhibit the transfer of impact noise and/or vibration to surrounding
structure. In noise
sensitive environments, the vibration damper may be used between sensitive
measurement and high-tolerance equipment such as for example MRI devices and
CNC machines to isolate the sensitive measurement and high-tolerance equipment
from vibration generated in the surrounding environment.
The vibration damper 10 can take basically any desired size. It has
been found that 4" by 6" vibration dampers are suitable to support loads in
the range
of from about 50 lbs to 400 lbs, 5" by 7" vibration dampers are suitable to
support
loads in the range of from about 100 lbs to 1,000 lbs and 6" by 14" vibration
dampers
are suitable to support loads in the range of from about 100 lbs to 2500 lbs.
As will be appreciated by those of skill in the art, the vibration
dampers need not directly support equipment. Rather, the vibration dampers can
be
used to support floor panels on which equipment is to rest. In this manner,
the
vibration dampers space the floor panels on which the equipment rests from the
underlying structure floor creating a floating floor for the equipment. Pre-
fabricated
ready-to-install floating floor sections, each comprising a plurality of
vibration
dampers adhered or otherwise secured to a floor panel such as a plywood sheet
at
spaced locations can be constructed allowing larger floating floors
incorporating the
vibration dampers to be quickly and easily installed.
Although embodiments of the vibration damper have been described
above with reference to the drawings, those of skill in the art will
appreciate that
variations and modifications may be made without departing from the scope
thereof
as defined by the appended claims.
