Stock material or miscellaneous articles – Composite – Of metal
Reexamination Certificate
1999-10-27
2001-05-22
Nakarani, D. S. (Department: 1773)
Stock material or miscellaneous articles
Composite
Of metal
C428S462000, C428S465000, C524S059000, C524S066000
Reexamination Certificate
active
06235400
ABSTRACT:
This application is based on Japanese Patent Application No. 11-117957 filed Apr. 26, 1999, the content of which is incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a vibration-isolating laminar rubber structure, and more particularly to a vibration-isolating laminar rubber structure suitably used as an elastic support or cushioning body for supporting a civil engineering structure or a building or architectural structure, in a vibration isolating or damping fashion. For instance, the laminar rubber structure is suitably used as a support interposed between a beam and a pier of a bridge.
2. Discussion of the Related Art
There has been known a vibration-isolating elastic support or cushioning body in the form of a laminar rubber structure used for supporting a structure in the fields of civil engineering and building or architectural construction. Such a laminar rubber structure is interposed between an upper structure and a lower structure. Since the upper structure to be supported by the laminar rubber structure usually has a considerably large weight, the laminar rubber structure is constructed to include metal plates or other hard plates having a high degree of rigidity, such that the hard plates and rubber layers are alternately laminated on each other to constitute a laminar structure, which is highly capable of functioning as an elastic support or cushioning body for supporting a building or architectural structure, or a bridge pier or other civil engineering structure, in a vibration damping or isolating manner.
Described in detail by reference to
FIG. 1
, a vibration-isolating laminar rubber structure
10
shown therein by way of example includes a rubber block
12
wherein a plurality of hard plates in the form of metal plates
14
are embedded in parallel with each other such that the metal plates
14
are spaced apart from each other at a predetermined spacing interval, so that the metal plates
14
and rubber layers
16
are alternately arranged to provide the rubber block
12
in the form of an integral laminar body. The laminar rubber structure
10
further includes an upper mounting plate
18
and a lower mounting plate
20
, which are both formed of a metallic material and secured to the respective upper and lower end faces of the rubber block
12
. The laminar rubber structure
10
is interposed between an upper structure such as a beam of a bridge and a lower structure such as a pier of the bridge, such that the laminar rubber structure
10
is fixed at the upper and lower mounting plates
18
,
20
to the beam and pier of the bridge, respectively. The laminar rubber structure
10
is capable of supporting a relatively large weight of the upper structure such as a concrete bridge beam having a large weight, in a vibration damping or isolating fashion. The laminar rubber structure
10
exhibits a damping or cushioning effect in a shearing direction, for absorbing or accommodating deflection, flexure or displacement of the bridge beam which may be caused by an earthquake, a strong wind, or a weight or acceleration of vehicles running on the bridge. The laminar rubber structure
10
also exhibits a damping or cushioning effect for absorbing or damping a vibrational load which acts on the bridge beam in the vertical direction.
It will be understood that the vibration-isolating laminar rubber structure constructed as described above desirably is required to exhibit not only a high vibration isolating, damping or absorbing effect, but also a low dependency of its modulus of elasticity on the temperature. Generally, the laminar rubber structure is used at a temperature which varies over a relatively wide range, Where the laminar rubber structure is used for supporting a bridge beam on a pier, the laminar rubber structure is usually placed in a severe natural environment, being exposed to a below-freezing temperature up to a temperature far exceeding 30° C.
However, the rubber layers in the rubber block provided in the conventional vibration-isolating laminar rubber structure are formed of an ordinary rubber composition which is a mixture of a rubber material such as a natural rubber (NR) and a suitable vulcanizing agent. Such an ordinary rubber composition is not satisfactory in its vibration isolating or damping properties. Further, the inclusion of known components conventionally used to improve the isolating or damping properties causes an undesirable increase in the temperature dependency of the modulus of elasticity of the rubber layers, namely, undesirable deterioration of its elastic characteristics of the laminar rubber structure as a whole, due to a considerable influence by the ambient temperature.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a vibration-isolating laminar rubber structure which exhibits an improved vibration isolating or damping effect, and reduced temperature dependency of its elastic characteristics.
The above object may be achieved according to the principle of this invention, which provides a vibration-isolating laminar rubber structure including highly rigid hard plates and rubber layers which are alternately laminated on each other, wherein the rubber layers are formed of a rubber composition comprising 1-50 parts by weight of at least one kind of material selected from among asphalt materials, tar materials and pitch materials, per 100 parts by weight of a rubber material.
The vibration-isolating laminar rubber structure of the present invention constructed as described above is characterized in that the rubber composition of the rubber layers interposed between the adjacent hard plates such as metal plates comprises a suitable amount of at least one kind of material selected from among asphalt materials, tar materials and pitch materials. The inclusion of the above-indicated at least one kind of material is effective to enable the laminar rubber structure to exhibit improved vibration isolating or damping properties, and reduced temperature dependency of elastic characteristics such as modulus of elasticity. Accordingly, the present vibration-isolating laminar rubber structure is capable of providing an improved damping or cushioning effect in a shearing direction, for efficiently absorbing or accommodating deflection, flexure or displacement of a bridge beam, for example, which may be caused by an earthquake, a strong wind, or a weight or acceleration of vehicles running on the bridge. Further, the laminar rubber structure is also capable of providing a damping or cushioning effect for absorbing or damping a vibrational load, which acts on the bridge beam in the vertical direction.
In one preferred form of this invention, the rubber material includes as a major component at least one of a natural rubber and a synthetic diene rubber.
In another preferred form of the invention, the rubber composition further comprises 10-150 parts by weight of carbon black, per 100 parts by weight of the rubber material, so as to reduce or eliminate an increase in the temperature dependency of the elastic characteristics of the laminar rubber structure, which would be caused by the inclusion of at least one kind of material selected from among asphalt materials, tar materials and pitch materials. Preferably, the carbon black consists of at least one kind of carbon selected from HAF carbon, ISAF carbon and SAF carbon.
In a further preferred form of this invention, the asphalt materials and the pitch materials have a softening point not lower than 110° C., so that not only the isolating or damping properties of the laminar rubber structure are further improved, but also the temperature dependency of the elastic characteristics is significantly reduced. In particular, natural asphalt materials are preferably used as the asphalt materials.
In a yet further preferred form of the invention, the rubber composition further comprises 1-50 parts by weight of a plasticizer having a freezing point not higher than −30° C. The inc
Natsubori Isao
Yamamoto Kenji
Yamamoto Kyoichi
Burr & Brown
Nakarani D. S.
Paulraj Christopher
Tokai Rubber Industries Ltd.
LandOfFree
Vibration-isolating laminar rubber structure having rubber... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Vibration-isolating laminar rubber structure having rubber..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vibration-isolating laminar rubber structure having rubber... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2532910