Methods and Compositions for Isolating a Payload from Vibration

Abstract

Improved isolation bearings, platforms, and tracks are disclosed for protecting a payload, for example delicate computer equipment such as a hard disk drive, from damage due to vibrations, such as seismic vibrations, as well as weaker vibrations due to HDD, motorized equipment, air conditioning, heating systems, and the like. The isolation platforms and bearings combine a plurality of shapes on their load bearing surfaces to increase stability of the payload even when subjected to vibrations of high velocity or intensity, and preferably have an elastomeric coating on all but a central portion of the load-bearing surfaces of the bearing plates.

Description

CROSS-REFERENCE TO OTHER APPLICATIONS

This non-provisional patent application claims priority pursuant to 35 U.S.C. 119(e) to U.S. Provisional Patent Application 61/310,599, filed Mar. 4, 2010, which is hereby specifically incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates, generally, to methods and compositions for isolating and cushioning a payload comprising a computer component from a wide range of vibration amplitudes, for example, from seismic vibrations as well as smaller amplitude vibrations caused by, for example, motorized equipment, air conditioners, heating systems and other vibrations common in data centers, power plants, IT (information technology) centers, and the like.

In preferred aspects the invention is directed to isolation bearings, such as seismic and isolation bearings utilizing a rolling sphere or hardened ball on a bearing surface. In one specific embodiment, the invention relates to an isolation bearing in which the load or a portion thereof is concentrated on one or more rolling sphere or hardened ball placed between bearing surfaces, at least one of which has a central cavity or depression and a cross-section comprising at least a combination two or more shapes selected from the group consisting of an arc, a constant slope, a parabola, other curves, other slopes, or a combination of any of these.

In preferred embodiments, the invention is useful for supporting and stabilizing a payload; in particular, for example, equipment such as computer components containing at least one hard disk drive (HDD) and other valuable and delicate equipment, from vibrations such as those caused by neighboring HDD, air conditioning systems, motorized equipment, heating systems, fans, and the like, which might otherwise damage such equipment.

SUMMARY OF THE INVENTION

Isolation bearings are generally used to protect, for example, bridges, buildings, computers, machines, delicate and/or dangerous equipment, and the like from damage due to seismic vibrations. The isolation bearings (and platforms and floors containing such isolation bearings) are typically configured to support a specific load, i.e., the mass and distribution of the payload being supported.

The conservative character of a seismic isolation bearing may be described in terms of the bearing's ability to absorb displacement energy against the gravitational force caused by seismic activity or other external applied forces, and thus to cushion the structure being supported from such displacement. In this regard, features such as a rubber bearing body, leaf spring, coil spring, or the like may be employed to urge the bearing back to its original, nominal position following a lateral displacement caused by an externally applied force such as a seismic tremor. In this context, the bearing “conserves” lateral displacement energy by storing a substantial portion of the applied energy, and releases this stored energy upon cessation of the externally applied force to pull or otherwise urge the bearing back to its nominal original position.

Certain isolation bearings may have a laminated rubber bearing body, reinforced with steel plates. More particularly, thin steel plates are interposed between relatively thick rubber plates, to produce an alternating steel/rubber laminated bearing body. The use of a thin steel plate between each rubber plate in the stack helps prevent the rubber from bulging outwardly at its perimeter in response to applied vertical bearing stresses. This arrangement permits the bearing body to support vertical forces much greater than would otherwise be supportable by an equal volume of rubber without the use of steel plates.

Other isolation bearings may comprise steel coil springs combined with snubbers (i.e., shock absorbers). These bearings are often used to vertically support the weight of the payload. Coil springs, described in International Patent Publication WO 2004/007871, are generally preferable to steel/rubber laminates in applications where the structure to be supported may undergo an upward vertical force, which might otherwise tend to separate the steel/rubber laminate. Rubber bearings are typically constructed of high damping rubber, or are otherwise supplemented with lead or steel yielders useful in dissipating applied energy.

Metallic yielders, however, are disadvantageous in that they inhibit or even prevent effective vertical isolation, particularly in assemblies wherein the metallic yielder is connected to both an upper bearing plate and an oppositely disposed lower bearing plate within which the rubber bearing body is sandwiched.

Steel spring mounts of the type typically used in conjunction with the isolation of payloads comprising apparatus and/or machines are generally unable to provide adequate energy dissipation, with the effect that such steel spring mounts generally result in wide bearing movements or oscillations. Such wide bearing movements may be compensated for through the use of snubbers or shock absorbers to aid in absorbing the energy of the lateral displacement. However, in use, the snubber may impart to the bearing an acceleration on the order of, or even greater than, the acceleration applied to the machine due to seismic activity alone.

Another example of an isolation bearing is one using a rolling spherical, or approximately spherical, rigid ball placed between rigid load-bearing plates. It will be understood that such a rigid ball may itself be referred to as a bearing (for example, a ball bearing), or the combination of the rigid ball and the supporting rigid plates may together be referred to as a bearing. In this description generally the word “bearing” shall be generally reserved for the entire assembly; however, in certain occasions the context may make clear that the sphere or ball itself is referred to as a bearing, such as, without limitation, through the use of terms such as “ball bearing”, “rolling bearing” or “spherical bearing”.

For example, one isolation bearing comprises a lower plate having a conical-shaped cavity and an upper plate having a substantially identical cavity with a rigid ball placed therebetween. Such a bearing is often known as a ball-in-cone type bearing. See e.g., Kemeny, U.S. Pat. No. 5,599,106.

In another example, an isolation bearing comprises a lower plate having a concave (having an arc-shaped cross sectional portion) shaped cavity and an upper plate having a substantially identical cavity with a rigid ball placed therebetween.

In yet another example, such a device includes a bearing comprising a lower plate having a parabolic shaped cavity and an upper plate having a substantially identical cavity with a rigid ball placed therebetween.

Isolation platforms having seismic bearings containing a variety of differently shaped load bearing surfaces are disclosed in e.g., International Patent Publication No. WO/2004/007871 and US 2006/0054767; Isolation platforms comprising floors are disclosed in e.g., U.S. Pat. No. 7,290,375. Each of these publications and patents, and every other patent, patent application, and publication cited in this patent application, is expressly and individually incorporated by reference herein in its entirety as part of this specification.

Isolation bearings of the “rolling ball” type may in general include a lower plate having, without limitation, a conical, concave or parabolic shaped cavity, a cavity having a constant or variable slope and an upper plate which may be identical or different to the lower plate, with a rigid ball placed therebetween. The lower plate rests or is fixed or placed on the ground, foundation, platform, support, floor or base surface, while the payload to be supported rests directly or indirectly on the top surface of the upper plate, or the platform or surface which is supported by the isolation bearing or bearings. In this way, when external vibrations such as seismic movements occur the lower plate moves relative to the upper plate via the rolling of the spherical ball between the upper and lower plates.

However, such devices are not without their own drawbacks. For example, depending on the size of the seismic vibration, the bearings may have a limited range of mobility, and thus be able to absorb and dissipate a limited range of seismic shock amplitudes before becoming ineffective. For example, the maximum amount of lateral displacement of the upper and lower plates relative to each other may be limited based on the size of the bearing or of the surrounding structure(s). Also, in isolation bearings and platforms containing rolling balls, a severe shock such as that caused by a strong seismic tremor, can cause such radical lateral displacement that the ball is ejected from the bearing, causing failure of the bearing.

In addition, an isolation bearing of the “rolling ball” variety which is configured to provide adequate isolation to payloads in the event of extreme vibrations (such as seismic shocks accompanying a large earthquake) are generally not effective in providing isolation against smaller vibrations, such as those caused by nearby motorized equipment (such as HDDs), air conditioning systems, heating systems, and the like. While these smaller vibrations are not as likely to cause obvious physical damage to a payload as strong seismic events, these smaller vibrations can have large effects on certain equipment such as (without limitation) computer components having hard drives and other exacting mechanical tracking mechanisms, such as those in data centers and other large-scale IT facilities, and similar facilities.

For example, hard disk drives (“HDD”), are non-volatile, random access devices for reading and writing digital data. HDDs feature spinning rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the platters.

Displacement of the red/write heads from the correct location over the platters due to even relatively small vibrations requires the red/write heads to correct the displacement by again seeking and finding the correct platter location to perform the desired operation. In the case of a relatively constant, “normal”, or regular vibration (such as that caused by an air conditioning system or nearby motorized equipment), this “retargeting” correction may be required multiple times before the desired operation can be completed. This results in far greater energy consumption by the HDD than would be required in a relatively vibration-free environment, and greater time for each operation to be completed. Accompanying the increased energy consumption is greater heat generation, and greater work and “wear and tear” on the HDD itself, which can lead to early failure of the hard drive.

There is therefore a continuing need for isolation systems, including isolation platforms, isolation floors, and isolation bearings, that are stable (i.e., have a reduced tendency to come apart in use), and which can withstand and absorb both large seismic shocks and smaller amplitude vibrations, such as those caused by nearby motorized equipment, air conditioning and heating systems and the like. Preferably the isolation systems are also easily integrated into the locations in which they are desired to be installed.

There is also need for isolation bearing structures that have reduced susceptibility to resonance or harmonic interactions between bearings, spheres, and bearing surfaces during a seismic vibration. Such interactions may be caused when bearing surfaces are discontinuous (for example in which the load-bearing surface has radial grooves or crests) or when, for example, a central apex or cavity is too deep. In such structures, when the bearing is subject to a strong vibration, the spheres may “bounce” in and out of the apex or cavity, over or through the groove or ridge, or cause a shaking of the bearing when it interacts with other isolation bearings in, for example, an isolation platform or isolation floor.

DETAILED DESCRIPTION OF THE INVENTION

Seismic isolation systems were originally used primarily to isolate and protect buildings, bridges, and other large structures from damage and failure due to seismic shock. More recently, seismic isolation techniques have been applied to the protection of delicate equipment such as laboratory equipment and computer components; for example, computer, power, and telecommunications components contained in corporate or university data centers, large scale IT facilities, sophisticated computer modeling facilities, e-mail and internet servers, motion picture studios having digital animation and special effects capabilities, and the like.

Thus, many isolation platform payloads today comprise racks of computer component equipment containing aggregated hard disk drives (HDD). These racks often fill data center rooms, and the HDD are prone to “normal” (i.e., normally present) vibration levels generated by, for example, other neighboring HDD, fans, air conditioning, power supplies, and the facility site itself. The effect of this vibration is magnified by the fact that today's ultra high-density drives contain tracks that are extremely small, making correct head positioning both more difficult and absolutely critical.

One of the greatest hindrances to HDD performance is therefore this “normal” vibration. Such vibration can push the head off track, causing missed platter revolutions and delays in data transfers and reductions in overall input/output (I/O) performance and data throughput and computer system generally. As a result, HDDs are therefore forced to work much harder to seek, read and write data. Re-reads and re-writes add time to I/O operations, and led to a number of workarounds, including short stroking strategies for writing only to the periphery of a disk, thus leaving much of disk capacity stranded; purchasing additional HDDs to increase the apparent capacity of the system; obtaining more expensive drives; deploying disk arrays and RAID. All of these workarounds increase costs and complexity.

In addition to increased I/O operation time and greater equipment expenses, vibration also costs energy due to the extra work the HDD must perform in order to read, write, or obtain the desired data; some estimates have indicated that energy costs could be reduced by 50% or more by reduction or elimination of vibrational effects.

Finally, greater energy consumption leads to greater heat generation, and an increase in air conditioning costs. Heat generation, and HDD overwork results in lower HDD life and greater failure rates.

Data Center Vibrations and Base Isolation Bearings

Unfortunately, current seismic isolation technology is generally ill equipped to attenuate of the smaller amplitude “normal” vibrations commonly experienced in data center HHD arrays. By definition these systems using springs and spring mounts employ robust springs which require a substantial vibration, on the order of a seismic vibration, to cause them to overcome the inertia of the payload relative to the ground, floor or other base support.

Rolling ball isolation systems typically utilize opposing substantially concave, conical, or parabolic bearing surfaces, often identical and opposing, to create a cavity into which a hardened sphere is placed. The sphere or ball makes contact with the upper bearing surface at a first point on the surface of the sphere, and with the lower bearing plate at a second point on the sphere located, when the bearing is at rest, approximately antipodal to the first point.

In the past resonance in rolling ball isolation bearings has been reduced, and the effectiveness of the bearing to isolate large (e.g., seismic) vibrations (particularly for isolating equipment such as racks of computer components such as those found in data centers) increased by applying an elastic rubber or elastomeric coating or laminate either to the ball, or to the bearing surface (or both), which absorbs some of the kinetic energy of the seismic vibration. In a variation of this method, some applications have used a ball made entirely of high density rubber or another elastomeric material. The polymer or rubber thus performs as a damping mechanism, slowing the rolling of the ball along the load-bearing plate surfaces, reducing the amount of post earthquake oscillation, and reducing the time required for the isolation bearing to come to rest.

However, this same coating makes the isolation platform relatively unresponsive to relatively small vibrations such as those routine in data center environments.

The present applicants have discovered a simple and elegant solution to this problem. Thus, in one embodiment of the present invention, it is an object to provide a rolling ball-type isolation platform that is effective to isolate a payload from both larger seismic events and smaller, more common, data center environmental vibrations.

In this embodiment an elastic coating, such as a rubber sheet, is bonded or otherwise applied to the surface of at least one isolation bearing plate, while leaving the center of the bearing plate (wherein the ball contacts the plate at rest) bare and untreated. Preferably, the plates are made of steel, although other sufficiently hard metals and polymers can be used to fabricate the plates. Additionally, preferably the balls are also made of uncoated metal, such as steel or another sufficiently strong hard metal. However, in other embodiments the ball or at least its surface may comprise an elastomeric material.

The elastomeric coating may be bonded to the isolation bearing plates using a vulcanization process, and may comprise a multilayered laminate of rubber or elastomeric sheets. Alternatively, one or more elastomeric sheet may be applied to the bearing surface using one or more sufficiently strong glues or other bonding agents, such as epoxy glues. In this case, the surface of the steel is preferably sanded, etched, or otherwise abraded, then cleaned with alcohol or another suitable cleaning solvent prior to bonding in order to facilitate the bonding process.

Bonding agents may include contact adhesives, such as those made by the 3M company and the Lord CHEMLOK® adhesives. Some adhesives have relatively long cure times, and should be permitted to fully cure before use.

The elastomeric coating to the isolation bearing plates is applied so that a central, preferably substantially circular, portion of the bearing remains uncoated with an elastomeric coating. Preferably the diameter of this central circular area is at least about the diameter of the rolling sphere or ball which will be located within the bearing cavity after assembly, or at least about ⅔ the diameter of the rolling sphere, or at least about the diameter of the rolling sphere, or at least 1.25 times the diameter of the rolling sphere, or at least 1.5 times the diameter of the rolling sphere, or at least about 1.75 times the diameter of the rolling sphere, or at least about 2 times the diameter of the rolling sphere.

While the parameters set forth above are preferred, it will be understood that in a given case the desired radius of the central, uncoated circular area will be best determined when consideration is also given to factors comprising the following: the size of the bearing plate or plates, the depth of the indentation on the bearing surface of one or more bearing plate, and/or by the shape of the bearing surface.

Cross Sectional Shape of the Bearing Plate Surface

The cross sectional shape of the bearing surface within the circular area—for example, whether it is concave (as in a spherical bearing surface), linear (as in a conical bearing surface), parabolic, or a combination of any one or more of these shapes) is an important factor dictating whether and, if so, how the magnitude of lateral force required to move the rolling ball changes as a function of its distance from the center of the plate, and the slope or curve. This function also provides an indication (particularly when combined with the depth data mentioned above) of the nature of the restoring force urging the ball to return to the center after a vibration ends. A more detailed description of this parameter, expressed in relation to the related issue of isolation bearing stability, follows.

For any substantially radially symmetrical load-bearing surface (for example as employed in the ball-in-cone bearing disclosed in Kemeny, U.S. Pat. No. 5,599,106 (the '106 patent), or in a concave, parabolic or other curved bearing of a combination of shapes), one can, in a top view of the bearing, draw a straight line segment extending from the center of the bearing to the perimeter of the bearing surface.

When a cross-section of a ball-in-cone bearing as disclosed in the '106 patent (with the cavity facing upward) is viewed along this line, the shape of this line substantially describes the hypotenuse of a right triangle whose other sides include the bottom of the bearing (parallel to the ground or floor surface), and the side of the bearing, defining the height from the center of the bearing to the highest point near the perimeter of the bearing reached during use by the rolling sphere. In a preferred embodiment, the upper load-bearing surface of the bearing may be identical to the load-bearing surface, but have an inverted orientation.

The geometry of the load-bearing surface is of particular relevance when considering the forces acting upon the bearing during and after it is subjected to a vibration, such as a seismic vibration.

The ball-in-cone bearing may therefore be used as an initial (and non-limiting) illustration of the relation of geometry and the physical principles at play in rolling ball isolation bearings. Since the ball rests between the upper and lower load-bearing surfaces, and in certain cases may rest in central apices or depressions of one or both such bearing surface, upon the application of a lateral force, such as a seismic shock, to the bearing there may be some initial resistance to displacement of the ball from these depressions. The resistance may be sufficient to prevent any substantial displacement of the two bearing surfaces with respect to each other if the applied lateral force is small enough. Thus, where present, the spherical shape of the central apices provides an initial restoring force urging the ball to remain within the central apex. This restoring force is identical regardless of the direction from which the lateral force is applied.

For the purposes of the present invention, in one embodiment the center of the load bearing surface may lack a central apex or depression in order to increase the sensitivity of the isolation bearing to smaller vibrations.

However, if the bearing surface has a central apex or depression, preferably the apex or depression is substantially circular in a top view, and is at least ½ the diameter of the rolling ball, or at least ⅔ the diameter of the rolling ball, or at least the diameter of the rolling ball, or at least 1.5 times the diameter of the rolling ball, or at least 2 times the diameter of the rolling ball, or more.

If the bearing has a central apex or depression it is very preferably approximately ½ the diameter of the rolling ball, or approximately ⅔ the diameter of the rolling ball, or approximately the diameter of the rolling ball, or approximately 1.5 times the diameter of the rolling ball, or approximately 2 times the diameter of the rolling ball.

Regardless whether the bearing possesses central apices or not, if the initial lateral force is great enough, the plates of the bearing will be moved relative to one another by the applied force through the action of the rolling ball. This means that the applied lateral force is strong enough to force the ball along the conical recessed surface. This requires that either the upper bearing surface or the ball (or both) move “uphill” against the force of gravity and the mass of the load placed on the upper plate of the claimed platform. Therefore, the lateral force is temporarily partially stored as vertical “potential energy”.

Once the ball is located on the recessed bearing surface, the physics are similar to those concerning an object placed on an inclined plane, since in a ball-in-cone bearing the recessed bearing surface has constant slope. For simplicity, FIG. 1 examines primarily the lower recessed surface and the ball, with the understanding that similar principles apply (although in mirror image) to the upper recessed surface, which “floats” upon and is supported by the rolling ball.

Thus, with reference to FIG. 1, F_g equals mg, where m is the combined mass of the ball and the load transferred upon the ball by the upper plate, and g is gravitational acceleration (9.81 m/s²). Although F_g is exerted downwards, on the inclined plane, F_g is comprised of two vectors: F_N (the normal force extending perpendicular to the surface of the plane) and F_p. Due to the shape of the ball, the force opposing F_p (F_f; the frictional force) is minimal and therefore disregarded in this diagram.

The magnitude of each of the vectors F_p and F_N is dictated by the angle of the inclined slope and the magnitude of F_g, and can be calculated geometrically from the Pythagorean theorem, where F_g²=F_N²+F_p². Thus, F_p is a constant, so long as the angle between the recessed surface and the horizon is also constant.

Therefore, once the lateral motion has caused the ball to displace onto either or both the upper or lower recessed bearing surface, F_p, the “restoring force” is constant because of the conical nature of the ball-in-cone surface.

It can now be clearly understood that a bearing surface having a very shallow central apex or depression (or entirely lacking such a feature) when combined with a relatively gentle slope (for example, almost horizontal) in the central area of the bearing, will be far more sensitive to the “normal” vibrations seen in many data centers than one having a deep central apex or steeply sloped central area requiring substantial force to move the top plate of the isolation bearing relative to the bottom plate.

Clearly the same thing is true of a bearing surface having a central portion in a concave (rather than a conical) shape. Thus, in cross-section the concave central bearing surface will be an arc of a circle. The depth of the arc can be expressed according to the following equation:

L=θ°·r·π/180

Where L is the length of the arc of a sector, θ° is the circular angle in degrees, and r is the radius of the circle.

Very preferably the curvature of the arc will correspond to a circular sector having a central angle of 90° or less, or about 45° or less, or about 40° or less or about 35° or less or about 30° or less or about 25° or less, or about 20° or less or about 15° or less or about 10° or less, or about 5° or less, or about 2.5° or less. It will also be appreciated that for a constant arc length (or constant area of the concave central portion of the bearing) the diminishing circular angle corresponds to a sector of a circle having an increasing radius. The smaller the circular angle, the shallower the curve, and the more responsive the central portion of the bearing surface will be to smaller vibrations, such as those experienced due to vibration commonly found in, for example, data centers.

The overall physics of a curved bearing surface can be explained with reference to the explanation of the ball-in cone bearing described above. If the bearing surface has a different cross-sectional shape (e.g., a concave shape) such that vertical displacement as a function of lateral displacement is not constant, the magnitude of the restoring force F_p as a function of lateral distance traveled by the rolling ball is also not constant. For example, if the cross-section of the bearing surface is a concave curve (that is, an arc of a circle) rather than linear, a radius through the center of the bearing surface to the perimeter of the bearing surface, when viewed in cross section, would yield a non-linear curve, rather than a constant (linear) slope. Thus, a restoring force F_p as a function of distance from the center of the bearing would not be constant if the recessed surface were concave. Rather, the restoring force (and vertical distance traveled) would increase as a function of the distance the ball travels from the center of the bearing (i.e., toward the perimeter of the bearing surface, where the steepness of the slope of the curve increases). In a concave curve, the rate of change of the restoring force is constant, but not the restoring force itself. Thus, with each unit of lateral distance traveled from the center of the bearing surface, the greater the vertical distance traveled, the greater the force required to make the sphere travel this laterial distance, and the greater the restoring force.

Other simple planar open curves (such as various parabolic or other concave curves) have the same basic character as the concave curve, except that neither the slope or the rate of change in the slope as a function of leteral distance traveled is constant. Thus, as the ball moves from the center of the bearing towards the perimeter of the bearing surface the change in vertical displacement as a function of lateral distance traveled increases at different non-constant rates depending upon the shape of the curve.

In the present invention it has been surprisingly found that an optimal configuration for the load-bearing surface of a rolling ball isolation bearing, particularly when the isolation bearing is subjected to a strenuous vibration and is used in conjunction with other isolation bearings (such as in an isolation platform, track, or floor), is a combination of more than one shape. In a preferred embodiment, when viewed in cross section, at least one of the upper or lower load-bearing surface has an enlarged (i.e, corresponding to a an arc of a circular sector having a small circular angle) concave central bearing portion, with a border around the perimeter of the bearing comprising a region of constant slope, as in a conical bearing.

Alternatively, a less preferred bearing surface still within the purview of the present invention may include a cross sectional parabolic curve, whereby the slope or curve is quite shallow at the center of the bearing and becomes increasing steep toward the edges of the bearing. Like the bearing surface described in the paragraph above, such a bearing surface would be sensitive to small vibrations such as those caused by motorized equipment, neighboring HDD, air conditioning and the like and yet would also be designed to store increasing amounts of substantial kinetic energy (suchas higher amplitude seismic vibrations) as vertical displacement against gravity at the edges of the bearing.

As indicated above, the present inventors have discovered that a rolling ball isolation bearing tends to perform more robustly, and will less disruptive harmonic resonance if either or both lead-bearing surfaces lack a central spherical depression of the approximate diameter of the rolling ball, or have a very shallow depression in the center.

Preferably the shapes of the curve and angle of the cross section of each load-bearing surface or “dish” are such that regardless of the input shear acceleration caused by the seismic event, the output is limited to a maximum acceleration. For example, in one embodiment of the invention, the output acceleration may be limited by the combined curve and angle of the dish to about 0.1 g or less, even when the input shear is about 0.3 g, or about 0.35 g, or about 0.4 g, about 0.5 g, or about 0.6 g, or about 0.7 g, or about 0.8 g, or about 0.9 g, or about 1.0 g or more.

In another embodiment the output acceleration may be limited by the combined curve and angle of the dish to about 0.8 g or less, even when the input shear is about 0.3 g, or about 0.35 g, or about 0.4 g, about 0.5 g, or about 0.6 g, or about 0.7 g, or about 0.8 g, or about 0.9 g, or about 1.0 g or more.

In another embodiment the output acceleration may be limited by the combined curve and angle of the dish to about 0.75 g or less, even when the input shear is about 0.3 g, or about 0.35 g, or about 0.4 g, about 0.5 g, or about 0.6 g, or about 0.7 g, or about 0.8 g, or about 0.9 g, or about 1.0 g or more.

The attenuation of the input shear forces are a function of the base shear input. Thus, the percentage attenuation can be up to about 66%, or up to about 71%, or up to about 75%, or up to about 80%, or up to about 83%, or up to about 86%, or up to about 88%, or up to about 90% or more.

It will be understood that the ranges of input shear, output shear and percentage attenuation presented above specifically disclose, and are intended to specifically disclose, all points between any two maximum and minimum values listed and any range from a value greater than 0 and up to any such maximum value listed.

Coated and Uncoated Portions of the Bearing Surface

As indicated previously in a preferred embodiment, the invention comprises as bearing surface as provided herein, having a relatively shallow central portion either with a shallow central apex or depression, or none at all, and having either a combination of different cross sectional shapes (such as a concave center and conical perimeter), or a parabolic shape such that the change in the slope of the bearing from the center to the perimeter is increasing and not constant.

In a particularly preferred embodiment, the invention comprises a central portion which is relatively friction-free (for example, with the surface of the bearing in the central portion uncoated with an elastomeric coating or sheet) and thereby sensitive to smaller vibrations such as those experienced in data centers due to motorized equipment, neighboring HDD, air conditioning and the like, and wherein the remaining portion of the bearing is coated with a damping material such as a rubber, neoprene or another elastomeric material to provide a damping effect and increasing bearing stability while reducing resonance in more substantial vibrations, such as seismic vibrations.

Generally, in accordance with various embodiments of the present invention, the isolation bearings of the present invention, or platforms, floors or instruments made using such isolation bearings may comprise upper or isolator plates or “dishes”, and lower or bearing plates or “dishes”, having a combination of two or more different cross-sectional shapes (or a complex shape, such as a parabolic shape), such as, without limitation, conical depressions, concave depressions, and/or parabolic depressions and other curved shapes. In a preferred configuration, the load-bearing surfaces of the dishes do not comprise ridges or depressions radiating substantially from the center of the dish to the perimeter of the dish or in any other direction, although there may be annular concentric regions of discontinuity between cross-sectional shapes.

Preferably, although not necessarily, the upper plate and lower plate are substantially alike, or identical, in their opposing surfaces. In such isolation bearings or platforms the upper plate supports the one or more loads, and the lower plate directly or indirectly contacts the floor, foundation, surface or area below the bearing or platform. Between the upper and lower plates or dishes, one or more rigid, spherical rolling ball is placed within the cavity or cavities formed from opposing, recessed compound bearing surfaces, thereby allowing the upper and lower plates to displace relative to one another by rolling on the ball. By “composite bearing surface” or “composite bearing” or “compound baring” is meant that the cross sectional shape of the recess or indentation of the bearing surface comprises a composite of more than one curve or line, a mixture of at least one curve and line, or a complex curve such as a parabola having a non-constant slope or non-constant rate of change in slope.

The spheres or balls are preferably made of metal, such as stainless steel, but in less preferred embodiments may be made of any sufficiently rigid material, including a polymer such as a plastic, a hard rubber, and the like. In certain embodiments the spheres or balls are not made of, or coated with, such an elastomeric polymer. Those of ordinary skill in the art will be aware that a hard, rigid ball, such as a stainless steel ball, making contact with a bearing surface of similar rigidity, will have a minimum of friction; thus, such a bearing is usually preferred for use in reducing vibrational effects on the payload in data center applications of the present invention.

On the other end of the vibrational spectrum, as lateral forces (e.g., in the form of seismic vibrations) are applied to a bearing, the upper plate is displaced laterally with respect to the lower plate, such that the rigid ball or balls therebetween roll and rotate freely in any direction and, if sufficiently hard and rigid and lacking in dampening, in an almost frictionless manner about their respective depressions or cavities. The ball or balls permit the bearing to store the energy of the vibration as potential energy by being raised to higher elevations along the bearing surface, such that, the ball(s) remain substantially in contact with the upper and lower plates and the upper and lower plates thus remain indirectly in contact with each other. Due a least in part to the combination of conical and concave (or other curved shapes), or parabolic shapes of the lower and/or upper plates' isolation bearing surfaces, the gravitational forces acting on the structure, and the structure's mass, produce a lateral force component tending to restore the bearing or platform to its original position, with the upper plate(s) being positioned substantially above the lower plate.

In the event that an outside force is sufficiently strong or long-lasting, or if the bearing or platform lacks sufficient stability, the upper and lower plate of a bearing may be forcefully moved laterally with sufficient force that the ball or sphere may be thrown from the bearing, causing bearing failure. Such an eventuality could obviously be catastrophic for the structure, equipment, or other load borne by the bearing or plurality of bearings comprising a isolation platform or floor (see for example e.g., U.S. Pat. No. 7,784,225 and U.S. Patent Publication No. 2007/0261323 for examples of isolation flooring and platforms, each hereby incorporated by reference herein in its entirety), and can be avoided by various means, including, for example, one or more of the following: the use of a isolation bearing of the present invention, the use of restraining straps holding the plates or pans together, or a “ball restraint” device that holds the sphere or ball between the two bearing surfaces.

The stability of the bearing, floor or isolation platform is increased through the size of its “footprint” (its width versus its height) as compared to the weight distribution of the load. For example, when considering a platform, distances between the apices of a first pan structure (containing, for example, four bearings of the type discussed above) preferably have a ratio of less than 1.25 in relation to the height, width and/or depth of the payload. Additionally, preferably, no more than half of the total weight of the payload is in the upper half of the payload.

Optionally, straps between and linking the upper and lower plates may be attached, thereby allowing lateral displacement between the plates, but preventing unwanted separation of the plates. In addition to, or instead of these straps, one or more isolation bearing restraint, for example those found in Moreno & Hubbard, U.S. patent application Ser. No. 12/567,548, hereby incorporated by reference herein in its entirety, may also be used, thereby freely permitting lateral displacement of the bearing due to the rolling sphere between the plates, but preventing bearing failure due to unwanted separation of the plates and/or separation or ejection of the rolling sphere or spheres themselves from between the upper and lower plates.

Therefore in summary, the rolling ball isolation bearings of the present invention comprise a significant advancement in the design of isolation bearings; such bearings are designed to have a complex cross-sectional shape to the recess or indentation of the bearing surface (either a combination of different curves and/or slopes or a parabolic shape), thereby providing greater restoring force in strong vibrations than in weaker vibrations. Such bearings therefore withstand strong seismic vibrations with reduced tendency for bearing failure or harmonic oscillation in the event of a strong earthquake. Preferably, although not necessarily, a coating, laminate, or other layer of elastomeric material over at least the perimeter area of at least one bearing surface aids in damping the effects of such a strong vibration.

At the same time, in preferred embodiments of the present invention, the central portion of the bearing surface is gently curved or sloping and remains uncoated with an elastomeric covering to enhance the sensitivity of the bearing to isolate the payload from smaller vibrations, such as those experienced in commercial or industrial environments such as data centers, power plants, IT centers and the like. In this way, where external vibrations caused by HDD, other motorized equipment, air conditioning and heating systems and similar vibration-causing machinery contribute to a “normal” vibration, the isolation bearings of the present invention provides a sensitive attenuation of acceleration to the payload, while also providing robust isolation protection against higher amplitude seismic events.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional aspects of the present invention will become evident upon reviewing the non-limiting embodiments described in the specification and the claims taken in conjunction with the accompanying figures, wherein:

FIG. 1 is a drawing showing the force vectors upon a rolling ball on an inclined plane.

FIG. 2 is a top view of the bearing surface of an embodiment of a compound bearing of the present invention.

FIG. 3 is a side view of the edge of an embodiment of a compound bearing of the present invention.

FIG. 4 is an exploded perspective of an extendable isolation platform having compound bearings as shown in FIG. 2 and FIG. 3.

FIG. 5 is a top view of the bearing surface of rolling ball isolation bearing of FIG. 2, in which an elastomeric coating is applied to the top of the bearing surface in all but a central circular portion of the bearing.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 has been described above with reference to a ball and cone type rolling ball bearing.

FIG. 2 shows a preferred embodiment of the compound bearing of the present invention. In this figure, the load bearing portion of the bearing (or “dish”) comprises, in a top view, a substantially circular load-bearing surface having a concentric central region 101 comprising a curved cross-sectional region, such as a spherical curve, and an annular region 103 ringing the central region and comprising a flat, sloped surface linking the central region 101 with a raised lip 105 at the perimeter of the circular load bearing region. Preferably, the central region 101 does not comprise a central dimple for the ball to rest within when the bearing is not subject to shear forces. However, in other embodiments the bearing may contain a central dimple for the ball to rest within when the bearing is at rest.

Still with reference to FIG. 2, in a preferred embodiment, the ratio, in a line segment extending from point a to point a′, of the diameter of the central region 101 to the remainder of the load-bearing surface (the annular region 103 and lip region 105), of about 2 to 1. Thus, in a preferred embodiment where the dish is 12 inches in total diameter, a dish having this ratio has a central region diameter of about 8 inches, with the annular region (which is passed through twice by the line segment) having a width of about 2 inches. The majority of this annular region (about 1.625 inches) is the flat, sloped surface, with the raised lip comprising about 0.375 inches of the 2 inch annular region. Those of ordinary skill in the art recognize that this ratio of the diameter of the central curved region 101 to the remainder of the load-bearing surface (the linear annular region 103 and lip region 105), may be arranged to have different values depending in part on the depth and shape of the recessed area of the bearing surface. Thus these ratios may be, for example, about 3:1, or about 2:1, or about 1:1, or about 1:2 or about 1:3.

FIG. 2 shows the perimeter portion of the same embodiment of the compound dish of the present invention in cross-section. As shown, the border 107 between the central, concave curved region 101 and the flat, sloped portion 103 is shown, with the approximately 1.6 inch length of this flat region rising 0.25 inches with a constant slope equaling about 0.25/1.6 or about 0.156. The border 109 between the substantially flat, sloped region 103 of the dish and the lip 105 is shown, with the lip rising in a substantially constant slope. In this embodiment, the slope is: approximately 0.25 inches of vertical rise in approximately 0.125 inches of horizontal length, or approximately 2. The lip becomes horizontal for about 0.25 inches before reaching the edge of the plate. In this case, the central, spherically curved region 101 has a radius of curvature of about 86 inches, meaning it corresponds to an arc of a circle having a radius of about 86 inches.

Those of ordinary skill in the art will immediately recognize based on the foregoing, that the embodiment described above is only one of various possible embodiments of the present invention. In particular, the exact curvature of the central, concave curved region 101 may be varied (for example, to a parabolic shape) without departing from the spirit of the invention.

FIG. 5 shows a top view of the isolation bearing surface shown in FIG. 2, wherein the linear region 103 and concave curved region 101 are shown. A central circular portion 111 of region 101 is left uncoated or covered; the remainder of the bearing surface (including, in this case, a perimeter portion of the concave curved region 101 is covered with a damping elastomeric coating, laminate, or layer 113. Thus, this bearing is optimized for damping strong seismic vibrations, while remaining sensitive to routine “normal” vibrations found, for example, in data center, power plant, and IT center environments.

It will be recognized, based on this disclosure, that the design of the composition bearing depicted in FIGS. 2, 3 and 5 may serve to provide somewhat greater restoring forces in less violent earthquakes or vibrations and in preferred embodiments simultaneously to isolate equipment from routine environmental vibration. Additionally, the total horizontal displacement will be less than would otherwise be the case with a simple conical or concave load-bearing surface in stronger earthquakes. Where the vibration is strong enough to cause the rolling ball to cross border 107, then the restorative force increases at a constant rate as the ball travels up the flat, sloped region 103, thereby helping to prevent excessive rocking of the bearing (or the load placed upon the bearing) when the upper plate seeks to return to equilibrium after the vibration has subsided.

In certain embodiments, the lack of a small central spherically curved dimple or recess (or a shallow central recess also contributes to a more smoothly operating isolation bearing during a strong vibration. Without such a recess the isolation bearing is less likely to fail or be damaged due to harmonic resonance.

Preferably, although not necessarily, opposing plates in a bearing have substantially identical load-bearing surfaces comprising compound curved and flat angled cross-sectional indentations substantially as described above. Although an isolation bearing typically has a single pair of load bearing plates (recess-containing plates) with a single recess each and a rolling rigid ball between them, in certain embodiments a single dish may be fabricated to have more than one recess. For example, FIG. 2 of U.S. Pat. No. 5,599,106, previously incorporated by reference herein, depicts a single “dish” having four recesses. However, in most applications it may be easier to make and use equipment having multiple plates, each comprising only a single bearing.

Using the compound bearings of the present invention, various apparatus, such as isolation platforms, isolation floors and the like can be fabricated. U.S. Pat. No. 7,784,225 is directed at isolation platforms, and U.S. Patent Application Publication No. 2007/0261323 is directed at seismically stable flooring; both of these inventions can benefit from the innovations of the present compound isolation bearing.

FIG. 4 shows a particularly preferred embodiment of such apparatus, an extendable isolation platform or track can be fabricated using the isolation bearings of the present invention for supporting a payload, such as sensitive computer or laboratory equipment and the like. In such an embodiment the track or isolation platform may comprise a plurality of linked isolation platforms, each such isolation platform as depicted in exploded form in FIG. 4, comprising:

a) a substantially flat, rectangular and generally planar lower pan segment (201) comprising a first side and a second side opposite said first side having at least two upward facing recesses comprised of a load-bearing material (203);
b) a substantially flat, rectangular and generally planar upper pan segment (205) comprising a first side and a second side opposite said first side having at least two downward facing recesses comprised of a load-bearing material (not shown);
wherein opposing recesses between said lower pan segment and said upper pan segment are aligned to define at least two cavities therebetween, each cavity containing at least one rigid ball (207) rollably supporting the upper pan segment upon the lower pan segment; and wherein each such isolation platform is structured to be linked to at least one additional, substantially identical, isolation platform using a plurality of rigid connecting members (209), and wherein the surface of the recesses have a cross-sectional profile comprising a combination of more than one linear slopes, more than one curves, or a combination of slopes and curves. Preferably all but a central circularly area of the rigid recessed bearing surfaces are coated with or bonded to an elastomeric coating, laminate or sheet to provide damping.

FIG. 4 shows one isolation platform, or isolation platform unit or segment (comprising upper and lower pan structures and rolling ball(s)), linked to one other platform, unit or segment. Those of ordinary skill in the art will understand that each such platform, unit or segment can be linked to at least two other identical platforms units or segments, and thus a “track” can be constructed for providing isolation protection, for example, to a data center room of HDD, computer or other delicate, easily damaged equipment.

In particular embodiments of this isolation platform, the recesses are contained within separate bearing plates that are affixed to the upper and lower pan segments using any effective method suitable to withstand the stresses of a seismic event, such as using nuts and bolts, welding to the pan, or by any other sufficiently hardy method of affixing. The pan segments themselves are comprised of a rigid material such as steel, a metal alloy, or a sufficiently rigid and strong polymer having a hardness to resist buckling, twisting and similar stresses expected to be encountered in a seismic event.

In other embodiments, the entire pan may comprise a single plate, with each such plate having a plurality of the complex recesses of the present invention. In this embodiment, therefore, there is no need for bolting, welding, or otherwise affixing plates to the pan, as in other configurations since they are all part of a unified plate. However, this embodiment may be heavier and more expensive to make than a configuration in which the plates are affixed to the pan, as above, and therefore may be of particular advantage when the cost of making such a “single plate” compound bearing is justified by the payload mass or other considerations. Such single plate compound bearings may also be applicable to very large loads such as buildings, bridges, and the like.

As indicated above, in an embodiment of the present invention the isolation platform comprising the compound bearing(s) may comprise two substantially flat, rectangular and generally planar pan segments, each having a first side and a second side opposite said first side having at least two recesses comprised of a load-bearing material and having a combination of cross-sectional shapes, and wherein the recesses of a lower pan surface and an upper pan surface face each other to form at least two cavities with at least one rigid ball rollably supporting the upper pan segment. It will be apparent that when each pan segment has, for example, two cavities, then the isolation platform will tend to be unstable as a single segment. This can be seen in e.g., FIG. 4 when considering only one of the two isolation platforms linked by connecting members 209. Such a platform becomes stable when joined to at least one other such pan segment.

Thus, the isolation platform comprising the compound bearing may be substantially rectangular in shape and comprise two cavities, each such cavity comprising a rigid rolling ball. In such a configuration the isolation platform will generally need to be rigidly and strongly connected, preferably to at least one other isolation platform unit or segment, in order to have sufficient stability to function effectively. Providing a rigid and strong connection to another isolation platform also serves to synchronize the movement of each isolation platform segment when it is subjected to a seismic stress.

It can therefore be seen that in another embodiment the compound bearing of the present invention may be employed in an isolation platform. Thus, for example, another embodiment of the invention may comprise a “track” or extended version of the isolation platform described above with horizontally extending “ties”, each such tie comprising the substantially rectangular isolation platform unit or segment having two cavities and a ball within each such cavity comprising a rigid rolling ball, and wherein the ties are preferably arranged parallel to each other and upper and lower pan structures are each connected using one or more rigid connecting member. Preferably, the upper and lower pan surfaces of each tie are each connected using two laterally affixed rigid connecting members.

In response to an external vibration, each of the linked two or more upper plate segments are displaced laterally together with respect to the linked two or more lower plate segments such that the rigid balls between the upper and lower plates roll about their respective bearing surfaces, thereby raising the balls and/or bearing surfaces to a higher elevation, and wherein at least one pair of opposing recesses comprise compound recesses, for example recesses wherein each (or at least one) bearing surface comprises a cross sectional profile having a central, approximately spherically curved region and a annular region comprising a flat, sloped surface.

In particularly preferred embodiments of the invention, the area of the annular region is at least equal to that of the central, approximately spherically curved region. For example the area of the annular region may be equal to, or approximately 1.1 times, or approximately 1.2 times, or approximately 1.3 times, or approximately 1.4 times or approximately 1.5 times, or greater than approximately 1.5 times the area of the central approximately spherically curved region of each load-bearing surface. However, in other embodiments the annular region may have a somewhat smaller are than the central region.

In other embodiments of the present invention, exemplified in the Figures hereof, the depressions and/or cavities in the lower bearing and isolator plates may have varied surfaces defining cavities, recesses, grooves, or combinations of grooves, of various shapes.

Preliminarily, it will be appreciated by one skilled in the art that the following description is of exemplary embodiments only and is not intended to limit the scope, applicability, or various possible configurations of the invention in any way. Rather, the following description merely provides convenient illustrations for implementing various embodiments or alternative configurations of the invention. For example, various changes may be made in the design and arrangement of the elements described in the exemplary embodiments herein without departing from the scope of the invention as set forth in the appended claims.

It will be understood that, in accordance with various embodiments, rather than the solely conical or concave load bearing surfaces previously known, each of the plates or pans may comprise a combination of corresponding recessed surfaces, for example, concave, generally conical surfaces, spherical, or parabolic surfaces which create a plurality of conical or spherical or parabolic cavities therebetween. Generally speaking, it should be appreciated that any suitable combination of radial or linear surfaces may be employed in the context of recesses in accordance with the present invention. In addition, the surfaces may have, for example, a combination of a continuous slope or a varying continuous slope.

With further particularity in the presently described exemplary embodiment, the downward and upward bearing surfaces may comprise central apices having the same curvature as that of the rigid spherical balls to prevent movement of the apparatus in the event of slight external forces. However, it may be desirable that the apices are shallow, or (in alternate embodiments even absent) so as to prevent resonance and harmonic disturbances when the apparatus is active after a significant vibration. Additionally, the surfaces may have recess perimeters surrounding the bearing surfaces such that the bearing surface connects the central apices and recess perimeters with either continuous (linear or curved) or varying slope. Thus, the curvature of the spherical balls and the downward and upward bearing surfaces are configured such that as the spherical balls and upper and lower plates displace laterally relative to one another, vertical displacement of upper and lower plates is generally less than lateral displacement.

Although the foregoing invention has been described in detail for purposes of clarity of understanding, it will be obvious that certain modifications may be practiced within the scope of the appended claims. Additionally, features illustrated herein as being present in a particular embodiment are intended, in aspects of the present invention, to be combinable with features not otherwise illustrated in this patent application as being present in that particular embodiment. Every publication and patent document cited herein is each hereby incorporated by reference in their entirety for all purposes to the same extent as if each were so individually denoted.

Claims

1) A rolling ball isolation bearing for supporting a payload comprising: said rolling ball isolation bearing structured so that if a vibration causes the lower plate to move, the inertia of said payload and upper plate causes said rolling ball to roll upwards from the central depression of the first recess, and wherein a cross-section passing through the center of either or both said first or second recess defines a line along the surface of said recess comprising a combination of shapes selected from the group consisting of:

a) a lower plate comprising a first recess comprising a lower bearing surface and having a substantially central depression, and

b) an upper plate upon which at least a portion of the payload is supported comprising a second recess comprising an upper bearing surface and having a substantially central depression, wherein said first and second recess oppose one another to form a cavity, and

c) a rigid rolling ball located within said cavity, said ball having a diameter wider than the combined depth of said first and second recesses and supporting the upper plate upon the load bearing surface of the lower plate;

i) a straight line and a curve,

ii) a first curve and a second curve different from the first curve, and

iii) a first straight line and a second straight line having a different slope than said first straight line, and

wherein the load bearing surface of at least one said recess is lined with an elastomeric polymer, and wherein a central portion of said bearing is free of said elastromeric polymer.

2) The isolation bearing of claim 1 wherein at least one of said first and second recess is at least partially conical in shape.

3) The isolation bearing of claim 1 wherein at least one of said first and second recess is at least partially concave in shape.

4) The isolation bearing of claim 1 wherein at least one of said first and second recess has a shape comprising a combination of conical and concave shapes.

5) The isolation bearing of claim 4 in which the cross-sectional shape of said at least one recess has a central approximately concave curved region and an annular region comprising a flat, sloped surface.

6) The isolation bearing of claim 5 in which the area of the annular region is at least equal to that of a central, approximately concave region.

7) The isolation bearing of claim 5 in which the flat sloped surface has a ratio of vertical rise to horizontal length of approximately 2.

8) The isolation bearing of claim 5 in which the central, concave curved region has a radius of curvature of about 86 inches.

9) The isolation bearing of claim 1 in which the central curved region has a parabolic shape.

10) An extendable isolation track comprising at least two linked isolation platforms, each such isolation platform comprising:

a) a substantially flat, rectangular and generally planar lower pan segment comprising a first side and a second side opposite said first side having at least two upward facing recesses;

b) a substantially flat, rectangular and generally planar upper pan segment comprising a first side and a second side opposite said first side having at least two downward-facing recesses structured to oppose said upward-facing recesses;

wherein said opposing recesses are aligned to define at least two cavities therebetween, each cavity containing at least one rigid ball rollably supporting the upper pan segment upon the lower pan segment;

wherein a cross-section passing through the center of at least one recess defines a line along the surface of said recess comprising a combination of shapes selected from the group consisting of: i) a straight line and a curve, ii) a first curve and a second curve different from the first curve, and iii) a first straight line and a second straight line having a different slope than said first straight line, wherein the load bearing surface of at least one said recess is lined with an elastomeric polymer, wherein a central circular portion of said bearing is free of said elastromeric polymer, and wherein each such isolation platform is structured to be linked to at least one additional, substantially identical, isolation platform using a plurality of rigid connecting members linking contiguous upper pan segments and contiguous lower pan segments.

11) The isolation track of claim 10 wherein at least two connecting members are laterally disposed along the sides of an isolation bearing.

12) The isolation track of claim 10 wherein at least two connecting members link opposite sides of an isolation platforms.

13) The isolation track of claim 10 comprising at least one isolation platform linked by a plurality of connecting members to at least two additional isolation platforms.

14) The isolation track of claim 10 wherein the cross-sectional shape of said at least one recess has a central, approximately spherically curved region and an annular region comprising a flat, sloped surface.

15) The isolation track of claim 14 in which the area of the annular region is at least equal to that of the central, approximately spherical region.

16) The isolation track of claim 14 in which the flat sloped surface has a ratio of vertical rise to horizontal length of approximately 2.

17) The isolation track of claim 14 in which the central, spherically curved region has a radius of curvature of about 86 inches.

18) The isolation track of claim 10 in which the payload is computer equipment.

19) The isolation track of claim 10 in which a gap between isolation platforms permits access to power or data cables.

20) A method of isolating a payload comprising at least one hard disk drive from vibration due to HDD, other motorized equipment, air conditioning and heating systems and similar vibration-causing machinery routinely found in a data center, IT center or power plant, comprising: placing said hard disk drive on a surface supported by a plurality of isolation bearings, each such bearing comprising said rolling ball isolation bearing structured so that if a vibration causes the lower plate to move, the inertia of said payload and upper plate causes said rolling ball to roll upwards from the central depression of the first recess, and

a) a lower plate comprising a first recess comprising a lower bearing surface and having a substantially central depression, and

b) an upper plate upon which at least a portion of the payload is supported comprising a second recess comprising an upper bearing surface and having a substantially central depression, wherein said first and second recess oppose one another to form a cavity, and

c) a rigid rolling ball located within said cavity, said ball having a diameter wider than the combined depth of said first and second recesses and supporting the upper plate upon the load bearing surface of the lower plate;

wherein the load bearing surface of at least one said recess is lined with an elastomeric polymer and a central circular portion of said bearing is free of said elastromeric polymer.