Acoustics – Sound-modifying means – Mechanical vibration attenuator
Reexamination Certificate
2000-01-28
2001-12-25
Nappi, Robert E. (Department: 2837)
Acoustics
Sound-modifying means
Mechanical vibration attenuator
C181S209000, C181S211000
Reexamination Certificate
active
06332509
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a noise reducer for construction equipment, and more particularly, to a device for effectively reducing noise.
BACKGROUND ART
As shown in, for example,
FIG. 20A
, a method of placing a vibration reducing member
21
of a viscoelastic body such as rubber, resin and the like on a vibrating element (base member)
22
is conventionally known as a noise reduction method for construction equipment. In this method, as shown in
FIG. 20B
, the vibration reducing member
21
placed on the vibrating element
22
is compulsorily expanded and contracted following the movement of the vibrating element
22
, which is vibrating, as shown by the arrows in FIG.
20
B. Then, due to the loss determined by the physical properties inside the vibration reducing member
21
in this situation, the vibrational energy is dispersed as thermal energy, thereby producing the effect of reducing vibration.
Further, as another noise reducing method of the prior art, for example, Japanese Utility Model Laid-open No. 55-174082 discloses a shoe plate (crawler belt) of a crawler vehicle, on which underside face a vibration damping means utilizing frictional loss is attached. According to the above, one end side of the vibration damping means (for example, spring steel plate) is fixed on the underside face of the shoe plate with bolts or the like, and the other end side is attached on the shoe plate while it is firmly pressed against the shoe plate (not fixed). When the shoe plate vibrates, due to the friction caused by the displacement of the other end portion of the vibration damping means and the shoe plate, the vibrational energy of the shoe plate rapidly decreases, thereby rapidly damping the vibration.
However, the above conventional noise reducing methods have the following disadvantages.
In the noise reducing method shown in FIG.
20
A and
FIG. 20B
, it is necessary to increase the thickness of the vibration reducing member
21
to produce a higher vibration reducing effect, and it is required that the thickness of the vibration reducing member
21
is more than twice to three times of the plate thickness of the vibrating element
22
. In the case of construction equipment, since the vibrating element (base member), to which the noise reducing member is applied, has the plate thickness of more than several millimeters to ten-odd millimeters, the required plate thickness of the vibration reducing member is almost about 10 millimeters to 50 millimeters. Consequently, the vibration reducing member
21
increases in cost due to the thickness as described above, besides being originally expensive since it is made of special material. In addition, in a place where the vibration reducing member
21
is placed, it is necessary to secure a space of a predetermined size in order to avoid interference with the other members, which causes the disadvantage of the device increasing in size. Further, in the case of construction equipment and the like which are used in various sites in the outdoors, there arises the disadvantage that the attaching portion of the vibration reducing member
21
has less durability against the environment (sunlight, weather, and the like), vibration, impact and abrasion (by rocks, stones, sands and the like).
Further, in the vibration damping means described in the embodiments of the shoe plate of the aforesaid Japanese Utility Model Laid-open No. 55-174082, one end side of the spring steel plate formed into a wave-shape is pressed against the shoe plate with bolts or the like to be attached thereto. However, due to the structure in which the plate formed into a wave-shape is fixed at only one end side and pressed against the shoe plate, dirt, sands and the like easily enter the gap between the spring steel plate and the shoe plate. If these sands and the like come into the aforesaid gap, the gap is widened, thereby eliminating or decreasing the loss of vibration caused by the frictional energy, thus causing the disadvantage that the noise reduction effect does not last for a long time. Further, due to the above structure, the spring steel plate is easily deformed by stones, rocks and the like, thus causing the disadvantage of less durability.
SUMMARY OF THE INVENTION
In view of the above conventional disadvantages, an object of the present invention is to provide a noise reducer for construction equipment, which efficiently reduces noise at lower cost with durability.
In order to attain the above object, a first aspect of a noise reducer for construction equipment according to the present invention is characterized by including
lamination plates which are the plates being laminated, and characterized by the lamination plates being bonded, discretely at a predetermined interval, to a part of or the entire of a noise generating element of the construction equipment.
According to the above structure, since the lamination plates are discretely bonded to the noise generating element (vibrating element), if the noise generating element vibrates, very small displacements and gaps are generated between the vibrating element and the lamination plates, and between the laminated plates. The very small displacements and the gaps are successively generated while always changing, and therefore friction and collisions are repeatedly caused between the plates as well as between the vibrating element and the lamination plates. Accordingly, the vibrational energy of the noise generating element is converted into thermal energy by the above friction and collisions to be dispersed, therefore making it possible to decrease vibration and reduce noise. In this situation, the laminated plates convert vibrational energy into thermal energy on the principle different from the internal loss of the conventional vibration reducing member of the viscoelastic body, specifically, by the friction and collisions between the plates as described above. As a result, even if each plate of the lamination plates is made thinner and the lamination height is made almost equal to or less than the plate thickness of the original vibration reducing element (base member), a sufficient noise reduction effect can be obtained. Consequently, the noise reducer can be reduced in size. Further, the laminated plate is not made of a special material like the vibration reducing member, but it may be made of a material with a friction coefficient of more than a predetermined value, such as a plain steel plate, aluminum, stainless steel or FRP (reinforced plastic material), therefore making it possible to reduce cost and improve durability.
A second aspect of a noise reducer for construction equipment according to the present invention is characterized by including
lamination plates which are the plates being laminated, and is characterized by the lamination plates being bonded, discretely at a plurality of kinds of bonding intervals, to a part of or the entire of a noise generating element of the construction equipment.
According to the above structure, since the lamination plates are discretely bonded to the noise generating element (vibrating element), if the noise generating element vibrates, very small displacements and gaps are generated between the vibrating element and the lamination plates, and between the laminated plates. The very small displacements and the gaps are successively generated while always changing, and therefore friction and collisions are repeatedly caused between the plates as well as between the vibrating element and the lamination plates. Accordingly, the vibrational energy of the noise generating element is converted into thermal energy by the above friction and collisions to be dispersed, therefore making it possible to decrease vibration and reduce noise. In this situation, if the bond interval of the lamination plates is made larger, noise in the low frequency band is further reduced, and if the bond interval is made smaller, noise in the high frequency band is further reduced, thus making it possible to set the frequency band of the noise to be reduced by changin
Nishikawa Kenji
Tsubota Haruhiro
Tsujino Masao
Armstrong, Westerman, Hattori, McLeland & Naughton, LLP.
Komatsu Ltd.
Martin Edgardo San
Nappi Robert E.
LandOfFree
Noise reducer for construction equipment does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Noise reducer for construction equipment, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Noise reducer for construction equipment will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2557379