Patent Description:
The present invention is related in general to vibration dampening and, in particular, to an apparatus of providing energy absorption for vibration dampening in a horizontal plane.

Road and wind vibrations are a significant impediment to a variety of vertical structures such as light poles. These vibrations are particularly problematic when the structure is lightly damped and road or wind excitations is near the natural frequencies of the structure. When this problem occurs, the energy of large excitations can cause fatigue failures of the structures.

A number of different solutions have been applied to reduce vibrations of poles. Prior art, in particular <CIT>, has used weights, solid ball(s), to impact the walls of a damper chamber to provide energy dissipation. The energy dissipation in this prior art has been limited to impact. More recently, <CIT> discloses a sealed bowl which dissipates energy as a mass damper approach, with a mass element, stiffness tuned at a particular frequency and damping of the moving mass achieved in some specific manner. The mass has been realized by a ball or a weight resting on balls. The stiffness is achieved by translating the mass on a curved surface, curved specifically to produce the desired frequency and effective stiffness. The damping is achieved by either an eddy current damper, friction between multiple solid balls, or impact against the walls of the damper. Other similar solutions, not applied to pole structures with translational vibration however, include filling a chamber with granular material to dissipate energy by either the granular material impacting the wall, friction against the other granular material as it moves about, or a paddle/element moving through the granular material. <CIT> discloses a seismic control structure for a building which acts as a dampening structure in this manner. Still further, <CIT> discloses a vibration dampening material which uses viscoelastic spheres to fill restricted areas such as structural boxes, walls and around pipes in this manner.

While each of the prior art solutions may be effective in selected circumstances, there remains an important need to provide further effective dampening for light poles and similar structures which are repeatedly subject to vibrations in a simple, robust and practical manner. Examples of prior arrangements are illustrated in SU patent number <CIT>), Chinese Patent Publication <CIT>) and article <NPL>). <CIT> discloses an apparatus for damping vibration in a horizontal plane, the apparatus comprising: an enclosed housing; wherein the enclosed housing is comprised of a bottom wall, a side wall and a top wall; a concave flooring surface, wherein the concave flooring surface is enclosed within the enclosed housing; and a dampening weight, wherein the dampening weight is located within the enclosed housing; wherein the dampening weight is comprised of an inner cavity; further wherein the dampening weight is further comprised of a plurality of dampening particles located within the inner cavity.

Based on the foregoing, there is a need for an apparatus for providing effective dampening of various modes of vibrations for a range of different types of poles. The present invention is different than other dampers using granular material as the granular material is placed inside a ball that translates in a damper housing. In prior realizations the granular material is placed directly into the chamber. Further, the prior art does not place granular material to provide damping as part of a tuned mass damper. The present invention damper is also different than <CIT> as the ball in the present invention serves two purposes, both mass and damping. In accordance with aspects of the present invention, the translating mass is both the shell of the ball and the granular material inside of the ball. Accordingly, the damping is achieved through friction and impact as the granular material tumbles within the ball.

To minimize the limitations found in the prior art, and to minimize other limitations that will be apparent upon the reading of the specifications, aspects of the present invention preferably include a spherical ball filled partially with granular material which preferably translates on a curved surface to dissipate energy as a tuned mass damper on a vertical structure. In this configuration, the curved surface of the present invention preferably provides an effective stiffness or restoring force that enacts the frequency tuning of the tuned mass damper.

According to a first preferred embodiment, the present invention discloses an apparatus for damping vibration of a pole. The apparatus preferably includes a housing with a horizontal floor having an inward curved surface for achieving vibration attenuation at a middle portion thereof to form an enclosed chamber. According to a further aspect of the first embodiment, at least one damping weight is preferably disposed in the inward curved surface and is preferably substantially spherical in shape. Preferably, the damping weights are disposed for free movement along the inward curved surface inside the enclosed chamber.

According to a further aspect of the present invention, at least one dampening weight of the present may preferably include a hollow, inner cavity. According to further aspects of the present invention, the dampening weight preferably may further include a granular material located within the inner cavity.

These and other advantages and features of the present invention are described with specificity so as to make the present invention understandable to one of ordinary' skill in the art.

Elements in the figures have not necessarily been drawn to scale in order to enhance their clarity and to improve understanding of these various elements and embodiments of the invention. Furthermore, elements that are known to be common and well understood to those in the industry are not depicted in order to provide a clear view' of the various embodiments of the invention, thus the drawings are generalized in form in the interest of clarity and conciseness.

Reference is now made in detail to the exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. The description, embodiments and figures are not to be taken as limiting the scope of the claims. It should also be understood that throughout this disclosure, unless logically required to be otherwise, where a process or method is shown or described, the steps of the method may be performed in any order, repetitively, iteratively or simultaneously. As used throughout this application, the word"may" is used in a permissive sense (i.e., meaning "having the potential to'), rather than the mandatory sense (i.e. meaning"must").

Additionally, any examples or illustrations given herein are not to be regarded in any way as restrictions on, limits to, or express definitions of, any term or terms with which they are utilized. Instead, these examples or illustrations are to be regarded as illustrative only. Those of ordinary skill in the art will appreciate that any term or terms with which these examples or illustrations are utilized will encompass other embodiments which may or may not be given therewith or elsewhere in the specification and all such embodiments are intended to be included within the scope of that term or terms.

Further, various inventive features are described below that can each be used independently of one another or in combination with other features. However, any single inventive feature may not address any of the problems discussed above or only address one of the problems discussed above. Further, one or more of the problems discussed above may not be fully addressed by any of the features described below.

<FIG>illustrates a perspective view <NUM> of an exemplary light pole <NUM> fitted with a dampening device <NUM> in accordance with a first aspect of the present invention. IB is an enlarged view of the dampening device <NUM> shown in <FIG>. As shown, the exemplary dampening device <NUM> may preferably be position at or near the top end of a light pole <NUM>. The mounting of the dampening device <NUM> may be with any form of connector or clamp of conventional construction. As should be understood, the light pole <NUM> is purely exemplary and the present invention may be attached to any structure to achieve the advantages of the present invention.

As further shown in <FIG>, the light pole <NUM> may preferably be further secured to a base <NUM> and may preferably support a light <NUM> Alternatively, the structure represented by the light pole <NUM> may further include a cantilevered arm or the like and may support various objects such as signs, traffic lights, over-head wires and the like. According to a further alternative preferred embodiment, the exemplary dampening device <NUM> of the present invention may alternatively be positioned in the mid and/or lower sections of the light pole <NUM> as discussed further below.

With reference now to <FIG>, a top perspective view <NUM> of the interior of the dampening device <NUM> shown in <FIG> is provided. As shown, the exemplary dampening device <NUM> may preferably include an enclosed lower portion <NUM> which includes a center floor <NUM> surrounded by an interior wall <NUM> and enclosed by an outer wall <NUM>. According to a preferred embodiment, the center floor <NUM> may preferably be concave with a constant radius. According to a further preferred embodiment, the center floor <NUM> may preferably be of a varying radius of curvature to achieve effective realizations of nonlinear energy sinks. Alternatively, the center floor <NUM> may be a flat surface (zero curve) bounded by the outer walls <NUM>. According to a further preferred embodiment, the interior wal! <NUM> may preferably be ringed with a deformable, impact absorbing material such as plastic, stuffed fabric or other padding type materials.

As further shown in <FIG>, the lower portion <NUM> of the dampening device <NUM> may preferably support and enclose one or more dampening spheres <NUM>. According to a preferred embodiment, the dampening spheres <NUM> of the present invention may preferably be hollow spheres which are selectively filled with energy absorbing materials as discussed with respect to <FIG> below.

With reference now to <FIG>, a cross-sectional view <NUM> of an exemplary dampening device <NUM> and dampening sphere <NUM> as shown in <FIG>, IB and <NUM> is provided. As shown in <FIG>, the dampening device <NUM> includes an inner surface <NUM> which preferably includes and forms a center floor <NUM> Further, the dampening device <NUM> preferably further includes an outer shell <NUM> which preferably encloses the inner surface <NUM> and at least one dampening sphere <NUM>. According to preferred embodiments, the inner surface <NUM> and the center floor <NUM> may substantially overlap and act as a single, curved surface as shown in <FIG>. Alternatively, the inner surface <NUM> may include a lip, edge, border or other boundary which defines a separate center floor <NUM> which is apart from other sections or walls of the inner surface <NUM>. According to a further preferred embodiment, the dampening sphere <NUM> may preferably include a hollow center region <NUM> which may be filled with energy absorbing particles and/or liquid <NUM>. According to a further preferred embodiment, the energy absorbing particles <NUM> may preferably be sand, aluminum, stainless-steel shot or the like. Alternatively, the energy absorbing particles <NUM> may be made of any material without limitation. For example, the particles <NUM> may be formed of materials such as: plastic, metal, rubber, stone, silicone, mercury and/or other materials which provide mass, and which can transfer kinetic energy.

According to an alternative preferred embodiment, the wails of the dampening device <NUM> may be utilized to abruptly stop the dampening sphere(s) <NUM> resulting in an impact load and dissipation of energy as the moving particles impact the inside wall of the moving sphere <NUM>. During such impacts, the kinetic energy of the moving particles is dissipated as the particles impact and come to rest. Preferably, the sphere(s) <NUM> acts as a mechanism to convert the energy of wind excitation and/or pole vibration into kinetic energy of the energy absorbing particles, while the sudden impact with the dampening device wall dissipates that energy. According to a further preferred embodiment, the interior wall(s) of the dampening device <NUM> can be coated with a material to absorb further energy and/or quiet the sound of the impact.

According to alternative preferred embodiments, the energy absorbing particles <NUM> may preferably be any size and may be formed from a variety of material s including stainless steel, sand, lead shot, aluminum and the like. Preferably, the materials may be selected based on their specific densities and their particular ability to capture and translate vibrational energy into kinetic energy within the dampening sphere <NUM>. According to a preferred embodiment, the particles <NUM> may preferably be of a sufficient density to allow for a greater absorption of higher energy vibrations.

According to a further preferred embodiment, the particles <NUM> of the present invention may preferably be sealed and protected against corrosion. Accordingly, the particles <NUM> may preferably be heated to a sufficient temperature prior to sealing to remove any humidity or moisture. According to a further preferred embodiment, <NUM>-<NUM>% of the interior volume of the dampening sphere <NUM> may preferably be filled with particles <NUM>. According to a further preferred embodiment, <NUM>-<NUM>% of the interior volume of the dampening sphere <NUM> may preferably be filled with particles <NUM>. According to a further preferred embodiment, <NUM>-<NUM>% of the interior volume of the dampening sphere <NUM> may preferably be filled with particles <NUM>. While these ranges are suggested, they are intended to be exemplary, and many other ranges may be used to address different vibrational environments. According to further alternati ve embodiments, the interior volume of the dampening sphere <NUM> may further be filled with a variety of liquids in addition to the particles <NUM> According to preferred embodiments, a liquid may be added in sufficient amounts to make a slurry mixture within the dampening sphere. According to further preferred embodiments, the liquid may include glycol antifreeze or the like to prevent freezing of the enclosed liquid(s).

According to an alternative preferred embodiment, the dampening sphere of the present invention may preferably include a first sized particle for use and attachment to the upper portions of the light pole <NUM> and a second sized particle for use and attachment to the mid or lower portion of the light pole <NUM>. According to a further preferred embodiment, the first sized particl es for use and attachment to the upper portions of the light pole <NUM> may have a lower density than the second sized particles. According to a further preferred embodiment, the first sized particles may preferably be selected and formed to most effectively absorb vibrational energy from wind vibration and/or the upper swaying of the pole <NUM>. According to a further preferred embodiment, the second sized particles may preferably be selected and formed to most effectively absorb vibrational energy from road vehicles and the like. The profile of center floor <NUM>, the material and physical properties of particles <NUM>, the size and interior volume of sphere <NUM> may all be adjusted to provide specific levels of mass, stiffness and damping for effective vibration mitigation of various applications. As shown in <FIG>, the dampening device <NUM> of the present invention may alternatively include a sloped or bowled lower surface <NUM> which acts as both the inner surface floor and the outer shell of the dampening device.

With reference now to <FIG>, an example of the operation of an exemplary dampening sphere <NUM> of the present invention shall now be discussed. In <FIG>, a cross-sectional view of a dampening sphere <NUM> is shown where the dampening sphere <NUM> is in a starting or zero-energy state <NUM> where the particles <NUM> are at rest and the dampening sphere <NUM> is not subject to vibrational forces.

<FIG> shows a cross-sectional view of the dampening sphere <NUM> in a first energy release state <NUM>. In this state, in response to vibrational forces, the dampening sphere <NUM> has been made to roll from a first position A to a second position B within the dampening device <NUM>. As shown, the particles <NUM> at position A have been raised to store potential energy which is then released in a tumbling or levelling action as the sphere <NUM> moves to position B. As further shown, in position B, the sphere <NUM> may impact the wall of the dampening device <NUM> and further transfer kinetic energy from the impact into sphere <NUM>.

<FIG> shows a cross-sectional view of the dampening sphere <NUM> in a second energyrelease state <NUM>. In this state <NUM>, in response to the movement of sphere <NUM> to a higher point on the center floor <NUM> (and/or a wall impact), the particles <NUM> at position A in <FIG> will preferably tumble and seek to level thereby releasing kinetic energy as the sphere moves to position B. Subsequently, at position B the particles <NUM> will preferably again store potential energy which is once again released in a tumbling or levelling action as the system moves back to energy release state <NUM> as discussed with respect to <FIG> above. According to preferred embodiments, with each change between the first and second energy release states, the kinetic energy of system is preferably continually reduced/dissipated due to the friction of the particles <NUM> and the retarding effects of gravitation.

In operation, the translation of the dampening sphere <NUM> from the first energy state <NUM> to the second energy state <NUM> may occur any number of times as energy is slowly dissipated from the dampening device <NUM>. As shown in <FIG>, once all the energy has been dissipated, the dampening sphere <NUM> preferably returns to a final zero-energy state <NUM>.

Claim 1:
An apparatus (<NUM>) for damping vibration in a horizontal plane, the apparatus comprising: an enclosed housing; wherein the enclosed housing is comprised of a bottom wall, a side wall and a top wall; a concave flooring surface (<NUM>), wherein the concave flooring surface (<NUM>) is enclosed within the enclosed housing; and a dampening weight (<NUM>), wherein the dampening weight is located within the enclosed housing; further wherein the dampening weight (<NUM>) is comprised of a spherical mass which is configured to freely roll on the concave flooring surface (<NUM>); characterized in that the dampening weight is comprised of an inner cavity (<NUM>); wherein the dampening weight is further comprised of a plurality of dampening particles (<NUM>) located within the inner cavity.