U.S. patent application number 14/471192 was filed with the patent office on 2016-03-03 for load adapting vibration isolation pallet mechanisms.
The applicant listed for this patent is International Business Machines Corporation. Invention is credited to Kenton C. Green, William J. Green, Michael D. O'Connell, Eric A. Stegner, Robert W. Stegner.
Application Number | 20160061285 14/471192 |
Document ID | / |
Family ID | 55401631 |
Filed Date | 2016-03-03 |
United States Patent
Application |
20160061285 |
Kind Code |
A1 |
Green; Kenton C. ; et
al. |
March 3, 2016 |
Load Adapting Vibration Isolation Pallet Mechanisms
Abstract
An isolation system for a transportation pallet, a
transportation pallet, and a method of providing an isolation
system are provided. The isolation system comprises a plunger
assembly comprising a graduated surface area having a first end
with a relatively smaller surface area than a second end having a
relatively larger surface area. The isolation system further
comprises a cushion pad coupled to the plunger assembly such that
when a load is applied to the plunger assembly, the plunger
assembly is pressed into the cushion pad to cause the cushion pad
to bear the load over a surface area of the plunger assembly
corresponding to the magnitude of the load. When the load is
increased, a larger surface area of the plunger assembly and the
cushion pad supports the load and as the load decreases, a smaller
surface area of the plunger assembly and cushion pad supports the
load
Inventors: |
Green; Kenton C.; (Cary,
NC) ; Green; William J.; (Cary, NC) ;
O'Connell; Michael D.; (Rochester, MN) ; Stegner;
Eric A.; (Durham, NC) ; Stegner; Robert W.;
(Raleigh, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
International Business Machines Corporation |
Armonk |
NY |
US |
|
|
Family ID: |
55401631 |
Appl. No.: |
14/471192 |
Filed: |
August 28, 2014 |
Current U.S.
Class: |
108/57.12 ;
267/141; 29/428 |
Current CPC
Class: |
B65D 2519/00024
20130101; B65D 2519/00064 20130101; B65D 2519/00378 20130101; B65D
2519/00034 20130101; B65D 2519/00273 20130101; B65D 19/0012
20130101; B65D 2519/00059 20130101; B65D 2519/00318 20130101; B65D
2519/00069 20130101; B65D 2519/00104 20130101; B65D 2519/00572
20130101; B65D 19/40 20130101; B65D 2519/00029 20130101; B65D
2519/00736 20130101; B65D 2519/00288 20130101; B65D 2519/00338
20130101; B65D 2519/00323 20130101; B65D 19/38 20130101; B65D
19/0028 20130101; B65D 2519/00114 20130101; F16F 15/08
20130101 |
International
Class: |
F16F 15/08 20060101
F16F015/08; B65D 19/38 20060101 B65D019/38 |
Claims
1. An isolation system for a transportation pallet, comprising: a
plunger assembly comprising a graduated surface area having a first
end of the plunger assembly with a relatively smaller surface area
than a second end having a relatively larger surface area; and a
cushion pad coupled to the plunger assembly such that when a load
is applied to the plunger assembly, the plunger assembly is pressed
into the cushion pad to cause the cushion pad to bear the load over
a surface area of the plunger assembly corresponding to the
magnitude of the load, and wherein as the load is increased a
larger surface area of the plunger assembly and the cushion pad
supports the load and as the load decreases, a smaller surface area
of the plunger assembly and cushion pad supports the load.
2. The isolation system of claim 1, wherein the cushion pad
comprises one or more layers of an elastomer material.
3. The isolation system of claim 2, wherein the elastomer material
is a neoprene material designed to provide a resonance frequency of
the transportation pallet at approximately 13 Hz.
4. The isolation system of claim 1, wherein the plunger assembly
comprises a plurality of load distributing elements configured in a
stack, and wherein at least one load distributing element of the
load distributing elements has a larger load bearing surface than
at least one other load distributing element in the stack.
5. The isolation system of claim 1, wherein the plunger assembly
comprises a single conical shaped piece having a relatively smaller
load bearing surface area positioned closest to the cushion pad and
a relatively larger load bearing surface area positioned furthest
from the cushion pad.
6. The isolation system of claim 1, wherein: the plunger assembly
and cushion pad are coupled to one another by a fastener core
member passing through the plunger assembly and cushion pad; the
isolation system further comprises a retention pad and stop
constraint coupled to the plunger assembly and cushion pad via the
fastener core member; and the retention pad and stop constraint are
loosely coupled to the fastener core member to allow movement of
the isolation system and transportation pallet along a long axis of
the fastener core member.
7. The isolation system of claim 6, wherein the retention pad and
stop constraint are positioned along the fastener core member to
permit a fixed amount of movement of the plunger assembly, cushion
pad, and transportation pallet due to side forces or tipping of the
transportation pallet.
8. The isolation system of claim 6, wherein the plunger assembly
and cushion pad are positioned along the fastener core member
between a lower deck and an upper deck of the transportation
pallet, and the retention pad and stop constraint are positioned
above the upper deck of the transportation pallet along the
fastener core member.
9. The isolation system of claim 8, wherein the retention pad sits
on an upper surface of the upper deck when no tipping of the
transportation pallet occurs and there is a gap along the fastener
core member between the retention pad and the stop constraint, and
wherein when tipping of the transportation pallet occurs, the
retention pad, upper deck, plunger assembly, cushion pad, and lower
deck are free to move along a long axis of the fastener core member
until the retention pad abuts the stop constraint.
10. The isolation system of claim 9, wherein the cushion pad is
subjected to only compression forces by the transportation pallet
during tipping of the transportation pallet due to the gap.
11. An isolation system for a transportation pallet, comprising: a
plunger assembly comprising a graduated surface area having a first
end of the plunger assembly with a relatively smaller surface area
than a second end having a relatively larger surface area; and a
cushion pad coupled to the plunger assembly such that when a load
is applied to the plunger assembly, the plunger assembly is pressed
into the cushion pad to cause the cushion pad to bear the load over
a surface area of the plunger assembly corresponding to the
magnitude of the load, and wherein as the load is increased a
larger surface area of the plunger assembly and the cushion pad
supports the load and as the load decreases, a smaller surface area
of the plunger assembly and cushion pad supports the load, wherein:
the plunger assembly and cushion pad are coupled to one another by
a metal bolt passing through the plunger assembly and cushion pad,
and a metal nut at one end of the bolt preventing the plunger
assembly and cushion pad from moving beyond the end of the bolt;
the plunger assembly is a stack of metal washers of differing
diameter, wherein the diameter of the washers in the stack
increases with increased distance from the cushion pad; and the
cushion pad is a pad comprising one or more layers of neoprene
material.
12. The isolation system of claim 1, wherein the isolation system,
via the plunger system and cushion pad, automatically adjusts for
varying loads from a minimum design load to a maximum design load
to provide a same vibration transmissibility over the entire range
from minimum design load to maximum design load.
13. The isolation system of claim 1, wherein the isolation system
reduces transmissibility of vibration to the transportation pallet
in the frequency range of 25 to 30 Hz.
14. A transportation pallet for transporting sensitive products,
comprising: a pallet comprising an upper deck and a lower deck; and
an isolation system located between the upper deck and the lower
deck of the pallet, wherein the isolation system comprises: a
plunger assembly comprising a graduated surface area having a first
end of the plunger assembly with a relatively smaller surface area
than a second end having a relatively larger surface area; and a
cushion pad coupled to the plunger assembly such that when a load
of a product loaded onto the pallet is applied to the plunger
assembly via the upper deck of the pallet, the plunger assembly is
pressed into the cushion pad to cause the cushion pad to bear the
load over a surface area of the plunger assembly corresponding to
the magnitude of the load, and wherein as the load is increased a
larger surface area of the plunger assembly and the cushion pad
supports the load and as the load decreases, a smaller surface area
of the plunger assembly and cushion pad supports the load.
15. The transportation pallet of claim 14, wherein the cushion pad
comprises one or more layers of an elastomer material.
16. The transportation pallet of claim 14, wherein the plunger
assembly comprises at least one of: a plurality of load
distributing elements configured in a stack, wherein at least one
load distributing element of the load distributing elements has a
larger load bearing surface than at least one other load
distributing element in the stack; or a single conical shaped piece
having a relatively smaller load bearing surface area positioned
closest to the cushion pad and a relatively larger load bearing
surface area positioned furthest from the cushion pad.
17. The transportation pallet of claim 14, wherein: the plunger
assembly and cushion pad are coupled to one another by a fastener
core member passing through the plunger assembly and cushion pad;
the isolation system further comprises a retention pad and stop
constraint coupled to the plunger assembly and cushion pad via the
fastener core member; and the retention pad and stop constraint are
loosely coupled to the fastener core member to allow movement of
the isolation system and pallet along a long axis of the fastener
core member.
18. The transportation pallet of claim 17, wherein the retention
pad and stop constraint are positioned along the fastener core
member to permit a fixed amount of movement of the plunger
assembly, cushion pad, and pallet due to side forces or tipping of
the transportation pallet.
19. The transportation pallet of claim 17, wherein the plunger
assembly and cushion pad are positioned along the fastener core
member between a lower deck and an upper deck of the transportation
pallet, and the retention pad and stop constraint are positioned
above the upper deck of the transportation pallet along the
fastener core member.
20. (canceled)
Description
BACKGROUND
[0001] The present application relates generally to an improved
data processing apparatus and method and more specifically to
mechanisms for providing a load adapting vibration isolation
pallet.
[0002] The transportation environment for sensitive computing
equipment has become more rigorous as global sourcing and customer
locations have increased transportation distance significantly.
Moreover, depending upon location infrastructure, the roadways and
shipping lanes that must be traversed to bring computing equipment
to the customer may cause significant vibration to be applied to
the computing equipment while it is being transported. This becomes
more of an issue with computing equipment as signal and power
connectors become smaller and less tolerant to vibration. As a
result, connector wear during shipment due to vibration has become
a major issue in the transportation of computing equipment.
SUMMARY
[0003] In one illustrative embodiment, an isolation system for a
transportation pallet is provided. The isolation system comprises a
plunger assembly comprising a graduated surface area having a first
end of the plunger assembly with a relatively smaller surface area
than a second end having a relatively larger surface area. The
isolation system further comprises a cushion pad coupled to the
plunger assembly such that when a load is applied to the plunger
assembly, the plunger assembly is pressed into the cushion pad to
cause the cushion pad to bear the load over a surface area of the
plunger assembly corresponding to the magnitude of the load. When
the load is increased, a larger surface area of the plunger
assembly and the cushion pad supports the load and as the load
decreases, a smaller surface area of the plunger assembly and
cushion pad supports the load.
[0004] In another illustrative embodiment, a transportation pallet
for transporting sensitive products is provided. The transportation
pallet comprises a pallet comprising an upper deck and a lower
deck, and an isolation system located between the upper deck and
the lower deck of the pallet. The isolation system comprises a
plunger assembly comprising a graduated surface area having a first
end of the plunger assembly with a relatively smaller surface area
than a second end having a relatively larger surface area. The
isolation system further comprises a cushion pad coupled to the
plunger assembly such that when a load of a product loaded onto the
pallet is applied to the plunger assembly via the upper deck of the
pallet, the plunger assembly is pressed into the cushion pad to
cause the cushion pad to bear the load over a surface area of the
plunger assembly corresponding to the magnitude of the load. As the
load is increased, a larger surface area of the plunger assembly
and the cushion pad supports the load and as the load decreases, a
smaller surface area of the plunger assembly and cushion pad
supports the load.
[0005] In still a further illustrative embodiment, a method of
providing a vibration isolation system for a pallet used to
transport a product is provided. The method comprises providing a
pallet comprising an upper deck and a lower deck. The method
further comprises providing an isolation system located between the
upper deck and the lower deck of the pallet. Providing the
isolation system comprises providing a plunger assembly comprising
a graduated surface area having a first end of the plunger assembly
with a relatively smaller surface area than a second end having a
relatively larger surface area. Providing the isolation system
further comprises providing a cushion pad coupled to the plunger
assembly such that when a load of a product loaded onto the pallet
is applied to the plunger assembly via the upper deck of the
pallet, the plunger assembly is pressed into the cushion pad to
cause the cushion pad to bear the load over a surface area of the
plunger assembly corresponding to the magnitude of the load. As the
load is increased a larger surface area of the plunger assembly and
the cushion pad supports the load and as the load decreases, a
smaller surface area of the plunger assembly and cushion pad
supports the load.
[0006] These and other features and advantages of the present
invention will be described in, or will become apparent to those of
ordinary skill in the art in view of, the following detailed
description of the example embodiments of the present
invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0007] The invention, as well as a preferred mode of use and
further objectives and advantages thereof, will best be understood
by reference to the following detailed description of illustrative
embodiments when read in conjunction with the accompanying
drawings, wherein:
[0008] FIG. 1 is an example diagram of a known shock pallet for
transporting electronic equipment;
[0009] FIG. 2 is an example plot of pallet, computing system, and
connector resonance frequency versus transmissibility for a desired
isolation system design and a load of approximately 2000
pounds;
[0010] FIG. 3 illustrates a similar plot as shown in FIG. 2 but
with a loading of approximately 100 pounds;
[0011] FIG. 4 is an example diagram illustrating an example
isolation system in accordance with one illustrative
embodiment;
[0012] FIG. 5 illustrates an example plot of frequency versus
transmissibility for lightly damped and highly damped isolation
systems;
[0013] FIG. 6 is an example diagram illustrating the retention pad
in combination with the isolation system having the plunger
assembly and cushion pad in accordance with one illustrative
embodiment;
[0014] FIG. 7 is a diagram illustrating a pallet that implements a
load adjusting vibration isolation system of the illustrative
embodiments;
[0015] FIG. 8 illustrates the load adapting vibration isolation
pallet during a tipping condition;
[0016] FIG. 9 illustrates an alternative configuration of a cushion
pad in accordance with one illustrative embodiment; and
[0017] FIG. 10 illustrates an alternative configuration of a
plunger assembly in accordance with one illustrative
embodiment.
DETAILED DESCRIPTION
[0018] The illustrative embodiments provide load adapting vibration
isolation pallet mechanisms. The mechanisms of the illustrative
embodiments provide a pallet that significantly reduces vibration
transferred to the palletized products that are being transported,
e.g., computing equipment or electronic equipment, while being able
to adapt to various loads, e.g., weights of products. The term
"palletized product" is used throughout this description to refer
to the product that is being transported in or by the load adapting
vibration isolation pallet of the illustrative embodiments. The
product is not limited in its type, but will generally be any
physical article that may be sensitive to vibration and thus, the
load adapting vibration isolation pallet of the illustrative
embodiments is employed to minimize the vibration transmitted to
the physical article. As mentioned above, one type of palletized
product may be computing equipment or electronic equipment.
However, other types of palletized products may include engines,
medical equipment, artwork, sculptures, house wares (china,
appliances, etc.), or any other article that may be breakable or
damageable due to vibration and/or overturning of the pallet.
[0019] With the mechanisms of the illustrative embodiments, a
plunger system with varying load bearing area is provided which
changes the stiffness of the isolation system as the load on the
pallet increase/decreases. This avoids vibration frequencies
approaching a resonant frequency of the palletized product being
transported and thereby reduces unwanted consequences of vibration
on the palletized product itself, connectors and other sensitive
components of the palletized products, and the like, during
transportation. In order to reduce motion at the pallet resonance
frequency without increasing damping (and consequently imparting
additional vibration to the palletized products at a resonance
frequency of the palletized products), a single sided isolation
(compression and not tension) system is utilized. In addition, a
bottom member or deck of the pallet is provided in conjunction with
a constraint system comprising a fastener with a highly damped
retention pad to prevent overturning of the pallet and products
while still being able to provide a single sided isolation
system.
[0020] In order to better understand the improvements and
advantages afforded by the mechanisms of the illustrative
embodiments, it is first important to understand the currently used
pallet mechanisms for handling transportation of products. In
particular, the mechanisms of the illustrative embodiments are
especially well suited for use in the transportation of computing
systems, electronic equipment, and the like, that have connectors
and other components that are sensitive to vibration, i.e. the
oscillation of a repetitive motion of an object about an
equilibrium point, but may also be used for transporting other
products, goods, etc. that are sensitive to vibration, e.g.,
vehicle or equipment engines, medical equipment, artwork,
sculptures, and the like. One implementation of the illustrative
embodiments is a load adapting vibration isolation pallet mechanism
for transporting server computing systems and/or racks of server
computing systems, such as a rack of one or more blade chassis with
one or more blade servers (or "blades") provided in the one or more
blade chassis.
[0021] Currently, the way in which such electronic equipment is
transported is to use what is referred to as a "shock pallet" as
shown in FIG. 1. The shock pallet 100 comprises a plywood deck 110
with a shock absorbing cushion or foam 120 underneath the plywood
deck 110 to reduce shocks from reaching the product in the enclosed
plywood compartment 130 from the movement of the vehicle in which
the shock pallet 100 is transported. Unfortunately, these shock
pallets 100 have several drawbacks. First, the shock absorbing
cushion 120 due to its material and configuration does not absorb
vibration or isolate the product from vibration to an acceptable
level for the transportation of sensitive products, e.g., computing
equipment, electronic equipment, medical equipment, engines,
artwork, or other types of sensitive products. In fact, in many
cases, the shock absorbing cushion 120 actually amplifies the
vibration frequency range that needs to be attenuated to protect
the sensitive product being transported, e.g., 25 to 30 Hz
vibration frequency for connectors of blade center chassis racks.
This is because the shock absorbing cushion 120 is designed to have
a large stiffness to reduce the large shocks. The result of the
stiffness of the cushion is that the cushion 120 drives the
resonant frequency up to approximately 25 to 30 Hz where the
sensitive product is sensitive to vibration input. Thus, with these
absorbing cushions 120, one could optimize a system for shock
absorption or vibration reduction, but not both.
[0022] Secondly, the shock pallet 100 is not tolerant of a wide
range of loads in the plywood compartment. That is, the shock
pallet 100 only works well with a certain load for which it is
designed and thus, a very narrow load range around the design load,
e.g., if the design load is 100 pounds, then the shock pallet 100
works well for loads within a small range of 100 pounds, for
example 90 to 120 pounds. However, many providers of products ship
products of various loads using the same pallet configurations. For
example, International Business Machines (IBM) Corporation, of
Armonk, N.Y., often ships rack mounted sensitive equipment that may
range in load from approximately 100 pounds to approximately 2000
pounds and such shock pallets 100 are not designed to accommodate
such a wide range of loads. Moreover, the shock pallet 100 is not
designed to adjust its vibration response based on changes in load.
For example, a provider may ship a product, e.g., a rack, with a
very light load to a value add reseller (VAR) who then, in turn,
may add thousands of pounds of additional equipment to the rack and
use the same shock pallet 100 for transportation of the modified
load. In such a case, either when shipping the light load, or when
shipping the higher load, or both, the vibration response of the
shock pallet 100 is not optimal since the shock pallet 100 is not
designed for the varying loads.
[0023] As a third drawback, the shock pallet 100 has a vibration
resonance and, in order to keep the vibration resonance from
becoming problematic, the vibration isolation afforded by the shock
absorbing cushion 120 is achieved by using a material with high
damping to reduce the mechanical amplification at the vibration
resonance. Unfortunately, the shock absorbing cushion 120 can in
fact transmit more vibration energy to the product being
transported at higher frequencies, which can damage the
product.
[0024] That is, the vibration energy from the vehicle is the same
for all of the shock pallets 100 being transported. However, the
pallets 100 themselves modify the vibration by amplifying the
vibration at some frequencies and attenuating the vibration at
other frequencies. Stiff pallets, such as those used for shock
absorption, tend to have relatively higher resonant frequencies,
meaning that they amplify the high frequencies. This is generally
an undesirable effect for sensitive products as discussed above.
However, a less stiff or soft pallet lowers the resonant frequency
of the pallet so that there is less damaging vibration getting
through the pallet to the sensitive product at its sensitive
frequency range, e.g., 25 to 30 Hz. Thus, varying the stiffness
will change the resonant frequency which can prevent energy
reaching the sensitive product at the sensitive frequency
range.
[0025] Another characteristic of the pallet 100 is its damping,
i.e. the energy that is lost, usually to heat. Since damping can
reduce the amplitude of vibration, it is often thought of as a
positive effect. However, in many cases damping can in fact make
situations worse. As will be discussed in greater detail hereafter,
damping can in fact reduce the amplitude of vibration at lower
frequencies, but may increase the vibration amplitude at higher
frequencies, which may include the sensitive frequency range of the
sensitive products.
[0026] A fourth drawback concerns the application of side loads to
the product being transported, such as because of fork truck
handling, ramps, vehicle motion of vehicles transporting the pallet
and product, etc. If not restrained properly, the product being
transported could overturn resulting in catastrophic damage to the
product and potentially causing injuries or even death for
personnel involved in the transportation of the product. Known
pallet configurations use thick shock absorbing cushions 120 in the
corners of the shock pallet 100, but these shock absorbing cushions
120, even with their increased thickness, can allow excessive
motion of the transported product and may even allow the product to
tear loose of the shock pallet 100 resulting in the product
overturning and damage to the product.
[0027] The illustrative embodiments provide a number of
improvements to shock pallets to avoid the drawbacks outlined
above. In particular, the illustrative embodiments provide a load
adapting vibration isolation pallet that uses a neoprene, or other
suitable cushion material, pad mechanism and plunger system that is
configured for adapting to varying loads. The illustrative
embodiments further provide a constraint system that prevents
overturning of the pallet and product without losing the benefits
of a single sided isolation system. These mechanisms will be
described hereafter with regard to the transportation of racks of
sensitive computer equipment, i.e. an example palletized product.
It should be appreciated that while the mechanisms of the
illustrative embodiments will be described hereafter with regard to
a load adapting vibration isolation pallet that is used for the
transportation of racks of computer equipment comprising various
types of connectors, the illustrative embodiments are not limited
to such and may be used with the transportation of any good or
product that is sensitive to vibration or may be damaged due to an
overturning of the pallet.
[0028] With regard to the transportation of racks of computer
equipment, such as racks comprising one or more blade chassis and
blade servers within the blade chassis, the computer equipment
often has many connectors that are sensitive to vibrations that
occur during transportation of the computer equipment. For example,
connectors between blade servers, chassis, hard drives and their
slots, power supplies in slots, cables, or any other connection
having a male end that plugs into a female slot. In general, with a
connection of any of these types, the connection conducts a current
or signal of some kind which generally requires an electrical
signal conductive coating (e.g., gold or other conductive
metal/material) to be provided on the male and female ends that are
connected to one another. If the two parts of the connection, i.e.
the part having the male end of the connection and the part having
the female end of the connection, do not move in unison, the
relative motion between the male and female ends cause the
conductive coating to rub off. This can cause signal/current
degradation, as well as corrosion, which can cause problems in the
operation of the computing equipment. Thus, it is desirable to
reduce the effects of vibration on the computing equipment during
transportation as much as possible. For example, it is desirable to
isolate computing equipment products from vibrations in
approximately the 25 to 30 Hz range, i.e. the problem frequency
range, where there may be significant connector wear.
[0029] As mentioned above, the foam materials used in shock
absorbing cushions 120 of known shock pallets 100 are not effective
in isolating the transported product from vibrations, and
especially in the 25 to 30 Hz range where connectors of electronic
devices may become damaged. The mechanisms of the illustrative
embodiments utilize a cushioning material that is designed to allow
the palletized product, i.e. the product being transported, to have
a pallet resonance frequency at 13 Hz, which will result in a good
isolation of the palletized product in the problem frequency range
of 25 to 30 Hz where the product is most sensitive, e.g., connector
wear occurs. In one illustrative embodiment, the cushioning
material is a heavy duty synthetic rubber, such as a heavy duty
neoprene material, that is formed into pads used in the
configuration described hereafter to provide a vibration damping
material. It should be appreciated that while the illustrative
embodiments will be described as utilizing neoprene pads, other
types of cushioning materials may be utilized as well or instead of
the neoprene pads including other types of synthetic elastomer
(rubber) materials and non-elastomer materials, e.g., polyethylene,
polystyrene, polyurethane, polypropylene pads, or bio-based
materials.
[0030] With regard to the use of neoprene as a cushioning material,
it has been determined that the most commonly used material for
shock absorption in shock pallets is polyethylene foam which can
handle moderate loads and is more robust than other shock foams.
Unfortunately, once the loading (pounds per square inch) on the
polyethylene foam is increased to achieve vibration isolation at 25
to 30 Hz, the polyethylene foam collapses and becomes useless. The
present inventors have determined that a high density neoprene
material may be used to provide vibration isolation for large loads
and can achieve a low resonant frequency, such as approximately 13
Hz, which will effectively isolate and protect palletized products
in the problem frequency range of approximately 25 to 30 Hz.
Providing cushioning pads at the outer edges, corners, and other
suitable locations, of the pallet will adequately support a fully
configured rack of computing equipment at approximately 2000
pounds, e.g., providing 6 pads place at the corners and edges of
the pallet with each pad being 2 layers thick (each layer being 3/8
inch thick) and 2.5 inches x 2.5 inches in size. While this will
provide sufficient cushioning to isolate the palletized product
from vibration, the use of this material alone does not resolve the
concerns with regard to effective isolation with a large range of
varying loads.
[0031] To fully understand the concerns with regard to vibration
isolation over a large range of varying loads, one must first
understand how a vibration isolation system is generally designed.
Initially one or more critical components, i.e. the component of
the palletized product that is most often damaged during
transportation, are identified that have a problem frequency range,
i.e. a frequency range in which damage to the component often
occurs or is most likely to occur. For example, in the case of a
rack of computing equipment, the critical component may be the
connectors in the rack of computing equipment. In this example
case, the problem frequency range is approximately 25 to 30 Hz due
to the product chassis having a resonance frequency at
approximately 25 to 30 Hz. If the chassis is excited with vibration
in this range, the chassis motion will wear on the connectors
causing the problems previously described above due to the
conductive material being rubbed off of the connectors, connectors
becoming loose, or the like.
[0032] In order to protect the product and its critical components,
a vibration isolation system needs to be designed. The "isolation
system" comprises the components of the pallet used to isolate
vibrations applied to the pallet from reaching the palletized
product. This may include, for example, cushion pads, fasteners,
and the like. As will be described hereafter, the isolation system
of the illustrative embodiments includes a cushion pad, plunger
system, fastener, upper and lower members or "decks" of the pallet
itself, and in some illustrative embodiments a retention pad and
fastener stop constraint. Thus, herein the term "isolation system"
will be used to refer to the components of the pallet that are used
to isolate vibration from the palletized product whereas the term
"pallet" is used to refer to the platform and optional container in
which the palletized product is transported. It should be
appreciated that the "pallet" may comprise the "isolation
system."
[0033] In designing the isolation system, in general the isolation
system should be designed such that the isolation system with the
palletized product on top of it will have a natural or resonant
frequency of about half of the problem frequency of the critical
components. This will cause the isolation system to be a poor
transmitter of the problem higher frequency range vibrations.
[0034] FIG. 2 is an example plot of pallet, computing system (or
just "system"), and connector resonance frequency versus
transmissibility for a desired isolation system design and a load
of approximately 2000 pounds. As shown in FIG. 2, the computing
system has a resonance at 25 Hz (represented by plot curve 210).
The isolation system of the pallet, when properly designed, would
have a natural frequency of 13 Hz (represented by plot curve 220)
and, as a result, the isolation system causes the pallet to
transfer very little vibration to the product in the 25 to 30 Hz
range. The result is the vibration motion at the connectors
represented by plot curve 230. Thus, this is a well designed system
which results in a relatively low transmissibility of 5 for the
connectors at 19 Hz. Thus, if the isolation system of the pallet
were carrying a load of approximately 2000 pounds, the isolation
system and pallet would be identified as having optimal
characteristics for that load.
[0035] However, often times pallets must be used to ship palletized
products that may be of varying weights depending on the particular
product, and the weights may vary over a large range of possible
weights, e.g., from 100 pounds to 2000 pounds. Moreover, in some
instances, the weight of the palletized product may vary during
transportation, e.g., additional equipment added to the palletized
product during transport, such as in the case of the VAR reseller
mentioned above. That is, the pallet and isolation system may be
reused for different loads. For example, in the example
pallet/isolation system whose characteristics are depicted in FIG.
2, the pallet/isolation system may be used to transport a load of
only 100 pounds, which will change the resonant frequency of the
isolation system/pallet and consequently its isolation frequency
and performance. The following equation describes how an isolation
system's resonant or natural frequency (Fn) is affected by changes
in mass (load):
Fn=(1/2.pi.)*sqrt(k/m) (Eq. 1)
where Fn is the natural frequency in Hertz (cycles/second), k is
the stiffness of the spring (Newtons/meter), and m is the mass
(kg). Thus, from equation 1 (Eq. 1) one can see that if there is a
significant reduction in mass (m) or load, the natural frequency Fn
increases significantly. This will have unfortunate consequences
for the connectors in the palletized product or other critical
components of the palletized product that are sensitive to
vibrations. That is, as shown in FIG. 3, which illustrates a
similar plot as shown in FIG. 2 but with a loading of approximately
100 pounds, because the mass of the system is significantly
reduced, the pallet resonance frequency is increased to 25 Hz, i.e.
the same frequency as the natural frequency of the palletized
product. To determine the vibration levels that the connectors
experience, one can multiply the pallet transmissibility by the
computing system transmissibility at each frequency and it can be
determined that the connectors experience up to 20 times the
vibration of the transporting vehicle with a light pallet load
(approximately 100 pounds) compared to 5 times the vibration with a
heavy pallet load (approximately 2000 pounds) in the above example.
This essentially increases the connector wear by a factor of 4.
This increase is due to the inflexibility of the isolation system
and pallet to differing loads over a wide load range.
[0036] To address this issue, the illustrative embodiments provide
an isolation system that is capable of changing its stiffness as
the load on the pallet is increased or decreased. The illustrative
embodiments utilize a plunger system comprising a plurality of load
bearing elements of varying sizes for varying the stiffness of the
isolation system and pallet. Due to the varying load bearing
elements of the plunger system, different amounts of stiffness are
achievable as the load changes and thus, the amount of vibration
isolation afforded by the isolation system may be maintained over a
wide range of loads on the pallet.
[0037] FIG. 4 is an example cross-sectional diagram illustrating an
example isolation system in accordance with one illustrative
embodiment. As shown in FIG. 4, the isolation system 400 comprises
a plunger system 410 that may be attached to an upper member or
deck 420 of the pallet and fastened thereto by a fastener 430. A
cushion pad 440 of the isolation system 400 is provided on an
opposite side of the plunger system 410 from the upper member 420
and is attached to the lower member or deck 450 of the pallet. The
fastener 430 comprises a fastener core member 432 and fastener end
or stop constraint 434. The fastener core member 432 and fastener
stop constraint 424 may comprise, in one illustrative embodiment, a
metal bolt and nut assembly in which the fastener core member
(bolt) 432 passes through a hole or opening in the lower member
450, the cushion pad 440, the plunger system 410, and the upper
member 420 and the fastener stop constraint (nut) 434 is provided
on the opposite side of the upper member 420 to fasten the elements
410-450 together. Of course, an opposite configuration may also be
used in which the nut 434 is provided on the opposite side of the
lower member 450 from the cushion pad 440. Moreover, other types of
fasteners may be utilized other than a nut and bolt assembly as
long as the fastener serves to hold the elements 410-450 together
such that the plunger system 410 and cushion pad 440 are sandwiched
between the upper member 420 and the lower member 450.
[0038] In one illustrative embodiment, the upper and lower members
or decks 420 and 440 are fabricated from a wood material, however
this is not required. The upper and lower members 420 and 440 may
be formed from any suitable material for forming a pallet upon
which a product is to be placed for transport including, but not
limited to, a plastic material, metal material, or the like. The
cushion pad 440, in some illustrative embodiments, is formed from
an elastomer material, such as a neoprene material as previously
described above, which is configured for providing an isolation
system or pallet with a natural frequency of approximately 13 Hz.
In other illustrative embodiments, the cushion pad 440 may be
formed from any suitable elastomer or non-elastomer material
including, but not limited to, those material described above,
which is configured to provide a natural frequency isolation system
or pallet that is suitable to the particular loadings expected and
resonance frequencies of the products being transported on the
pallet.
[0039] The plunger assembly 410 comprises a plurality of load
distribution elements 412 and 414 having different sizes or widths
with differing amounts of load bearing surfaces. The load
distribution elements 412 and 414 are preferably organized in the
plunger assembly 410 relative to the cushion pad 440 such that the
larger sized load distribution elements are further away from the
cushion pad 440 than smaller sized load distribution elements. In
this way, as the load increases, the load bearing surfaces upon
which the load is distributed is increased due to the pressing down
of the plunger assembly 410 into the cushion pad 440 as described
hereafter. Only two load distribution elements 412 and 414 are
shown in this depicted example for simplicity but any number of
load distribution elements greater than one may be utilized without
departing from the spirit and scope of the illustrative
embodiments.
[0040] In the depicted example, the load distribution elements 412,
414 may be washers of increasing size, for example, but are not
limited to such and any load distribution element may be utilized
in the illustrative embodiments, e.g., conical elements as
described hereafter, square, rectangular, or any other shape plates
with increasing dimensions, or the like The different sizes of load
distribution elements 412, 414 serve to increasingly distribute the
load imparted to the plunger assembly over a greater load bearing
surface area as described hereafter. Thus, as shown in FIG. 4, the
size of the load distribution elements 412 and 414 increases the
further away from the cushion pad 440 the load distribution element
412, 414 is positioned. Thus, in the depicted example, the upper
load distribution element 414 has a larger size than the lower load
distribution element 412. This size differential, in one
illustrative embodiment, is achieved by having load distribution
elements 412, 414 that have different diameters or widths. That is,
the load distribution elements 412 and 414 are circular in
configuration and thus have differing diameters with the load
distribution element 414 having a larger diameter than the lower
load distribution element 412.
[0041] It should be appreciated that while the depicted example
illustrates the plunger assembly 410 as having circular configured
load distribution elements 412 and 414, the illustrated embodiments
are not limited to such. To the contrary, the load distribution
elements 412 and 414 may have any suitable configuration or shape
as determined to be appropriate to the particular implementation
sought. The key feature is that there is a difference in load
distribution ability of the load distribution elements 412 and 414
and the load distribution elements 412 and 414 are positioned
relative to the cushion pad 440 such that the load is distributed
over increasingly larger load distribution elements 412 and 414 as
the load of the product 460 increases, i.e. increasingly larger
load distribution areas provided by larger sized load distribution
elements 412, 414.
[0042] Thus, in the example illustrative embodiment in FIG. 4, the
upper member 420, plunger assembly 410, and cushion pad 440 rest on
the lower member 450. The palletized product 460 is placed on top
of, and fastened to, the upper member 420 such that the weight of
the palletized product 460 is born by the combination of the upper
member 420, the plunger assembly 410, cushion pad 440, and lower
member 450. It should be appreciated that as the load on the upper
member 420 increases with an increased weight of the palletized
product 460, the plunger assembly 410 is pressed into the cushion
pad 440 such that larger load distribution elements 412, 414 of the
plunger assembly 410 are pressed into the cushion pad 440 until the
load is supported by the full area of the cushion pad 440.
[0043] That is, with very light loads the weight of the product
460, e.g., a rack of computer equipment, is carried by the smaller
diameter load distribution element 412 resting on the cushion pad
440 (e.g., a neoprene pad), i.e. the load is distributed over the
area 470 of the load distribution element 412. As the load on the
pallet increases, such as due to an increase in the weight of the
product 460, the area 470 of the smaller diameter load distribution
element 412 is pressed downward into the cushion pad 440 and
becomes fully embedded in the cushion pad 440. As a result, the
area 480 of the larger diameter load distribution element 414
starts bearing on the cushion pad 440. Finally, under a maximum
load, the upper member 420 of the pallet rests on the entire
cushion pad 440 and the load of the product 460 is distributed over
the entire area 490 of the cushion pad 440.
[0044] Thus, with the plunger assembly 410, as the load increases,
the load bearing surface becomes larger such that the load is
distributed over an increasing area and the cushion pad 440 becomes
harder to compress, i.e. the isolation system becomes more stiff.
This is not because of a change in the properties of the cushion
pad 440, but because the load bearing surface is increased allowing
more of the cushion pad 440 to support the load.
[0045] It should be appreciated that with the plunger assembly 410
of the illustrative embodiments, the plunger assembly 410 may be
designed for any desired minimum load and any number of increases
in load, represented by additional load distribution elements being
provided in the plunger assembly 410, to what is considered to be a
maximum feasible load for the pallet. While separate load
distribution elements may be provided, the adjustment of the
isolation system to the load is continuous rather than incremental
since as the load increases, the plunger assembly 410 continuously
bears down on the cushion pad 440 such that more and more surface
area of the plunger assembly 410 is supported by the cushion pad
440 until all of the plunger assembly 410 is embedded in the
cushion pad 440 and the entire cushion pad 440 then supports the
load. That is, the plunger assembly 410 allows the isolation system
400 of the pallet to automatically adjust to different loads
without the operator having to do anything other than load the
product 460 onto the pallet.
[0046] It should be appreciated that while FIG. 4 illustrates only
one such isolation system 400, the pallet may in fact comprise a
plurality of such isolation systems 400 at various locations of the
pallet, e.g., at each of the four corners of a rectangular pallet,
at one or more locations between the four corners of the
rectangular pallet, and/or at various other locations across the
lower surface of the upper member 420 and upper service of the
lower member 430 of the pallet.
[0047] The result is a stiffening compression curve which will
adapt itself to any load placed on the pallet. Hence, the net
result is that increasing mass on the pallet causes the isolation
system 400, comprising the elements 410-450, to become stiffer such
that the natural frequency remains approximately the same
throughout the load range, i.e. a range from a minimum load to a
maximum load (e.g., approximately 100 pounds to approximately 2000
pounds). Test results from a package test lab show that with a
heavy load of approximately 2000 pounds, both the known shock
pallet mechanisms and the pallet implementing the isolation system
400 of the illustrative embodiments, i.e. the load adapting pallet,
have resonant frequencies of approximately 7 Hz (8 Hz for the known
shock pallet and 7 Hz for the load adapting pallet of the
illustrative embodiments). However, the difference between the
known shock pallet mechanism and the load adapting pallet of the
illustrative embodiments happens with lower load configurations.
For example, for a minimum load configuration of approximately 100
pounds, the known shock pallet resonance frequency increase to 25
Hz which will cause connector wear in electronic systems that are
loaded onto the shock pallet, however the load adapting pallet of
the illustrative embodiments adjusts to the lighter load and the
resonance frequency increases to only 13 Hz. At 13 Hz the load
adapting pallet of the illustrative embodiments provides good
vibration isolation and protects the critical components of the
palletized product, e.g., the connectors of the rack of computing
equipment or other electronic equipment.
[0048] Moreover, at the maximum load configuration, the known shock
pallet has a transmissibility of approximately 3.1 and the load
adapting pallet has a transmissibility of approximately 3.6.
However, at the minimum load configuration, the known shock pallet
has a transmissibility of approximately 4.7 while the load adapting
pallet has a transmissibility of only 3.6. Thus, the
transmissibility of the known shock pallet increases considerably
with lower load whereas the transmissibility of the load adapting
pallet remains constant regardless of load.
[0049] It should be appreciated that while the above illustrative
embodiments are described with regard to increasing load, the
mechanisms of the illustrative embodiments may also adjust to
decreasing loads as well. The weight of the load is what controls
the operation of the isolation system 400 such that increased load
causes an increase in the stiffness of the isolation system 400 and
pallet while a decreased weight decreases the stiffness. The
cushion pad 440 is preferably manufactured from a material that may
recover from compression in this manner, such as the neoprene
material previously described above, such that the load may vary
from lighter to heavier and from heavier to lighter without
adversely affecting the ability of the isolation system 400 to
isolate vibration.
[0050] In addition to being able to automatically adjust to changes
in load of the palletized product, the isolation system of the
illustrative embodiments may further provide mechanisms for
controlling the amplitude of the pallet's resonance frequency.
Normally, such as in the known shock pallet, the pallet resonance
frequency is controlled with damping in the cushion pad material.
However, if there is insufficient damping in the cushion pad
material, the amplitude of the resonance frequency of the pallet
may be so high that the palletized product can physically break the
pallet and the palletized product can break away from the pallet as
well, which may cause damage to the palletized product. However, as
damping is increased, the peak in the transmissibility curve is
lower and wider. Thus, with too much damping, the isolation system
transfers more vibration to the palletized product in the problem
frequency range, e.g., the 25 to 30 Hz range, for example.
[0051] FIG. 5 illustrates an example plot of frequency versus
transmissibility for lightly damped and highly damped isolation
systems. As shown in FIG. 5, the highly damped pallet, represented
by curve 510, inputs more vibration, i.e. has a higher
transmissibility, at the problematic frequency of 25 Hz
(represented by line 520), than the lower damped pallet represented
by the curve 530. Thus, while it is preferable to have a lightly
damped pallet for vibration transmissibility reasons, a lightly
damped pallet would allow the resonance frequency to increase to a
level where the palletized product may break the pallet as noted
above.
[0052] It should be appreciated that, with the known shock pallets,
the pallet is attached to the cushion pad in such a way that when
the palletized product travels upwards, such as due to tipping of
the pallet, a side force from a fork truck or traversing a grade
such as a ramp or the like, the palletized product, which is
attached to the pallet, applies a tension force on the cushion pad
effectively pulling on the cushion pad, and the cushion pad then
applies a downward force on the palletized product. This additional
force on the cushion pad results in additional amplitude of the
vibration that is transmitted to the palletized product.
[0053] With the mechanisms of the illustrative embodiments, to
minimize the pallet resonance without resorting to high damping in
the cushion pad material, and the associated problems with such
high damping, as well as provide a restraint in the case of the
palletized product tipping, a mechanism is provided for providing a
single sided isolation system where the cushion pad is only
compressed and not subject to tension. The mechanism provides a
"single sided spring" operation in which only a compressive force
is exerted upwards on the cushion pad 440 by the bottom member 450
of the pallet. The single sided spring operation is achieved by
utilizing a soft but highly damped retention pad positioned between
the upper surface of the upper member 420 of the pallet and a
fastener end (or stop constraint) that is loosely attached, i.e.
not fastened down to prevent movement of the retention pad. A gap
exists between the highly damped retention pad and the fastener end
to allow the isolation system to vibrate freely and thus, allows
the palletized product to vibrate with lower amplitude due to less
transmissibility, as a single sided spring would. In the event that
the palletized product starts to tip due to handling, since the
palletized product is fastened to the upper member 420 of the
pallet, the upper member 420 of the pallet moves upward along a
path constrained by the fastener until the retention pad is brought
into contact with the fastener end to thereby prevent the
palletized product from overturning.
[0054] FIG. 6 is an example diagram illustrating the retention pad
in combination with the isolation system having the plunger
assembly and cushion pad in accordance with one illustrative
embodiment. As shown in FIG. 6, the isolation system comprises the
same components as discussed above with regard to FIG. 4 and thus,
like elements are shown with like reference numerals. Thus, the
isolation system 600 comprises the plunger assembly 410 comprising
the load distribution elements 412, 414, the upper member 420 of
the pallet, the fastener 430, the cushion pad 440, and the lower
member 450 of the pallet.
[0055] In addition to these elements, the depicted isolation system
600 further comprises a retention pad 610, a washer 620, and a
fastener end or stop constraint 630, such as a nut, fastener cap,
or other fastener stop constraint that prevents the other elements
410, 420, 440, 450, 610, and 620 from sliding off of the fastener
core member 432. The retention pad 610 may be fabricated from any
suitable soft but highly damped material, such as an elastomer
material, suitable non-elastomer material such as those described
above with regard to the cushion pad 440, or the like. In one
illustrative embodiment, the retention pad 610 is also formed from
a neoprene material that the cushion pad 440 is fashioned from,
although the material properties may be different depending on the
implementation. The washer 620 and stop constraint 630 may be made
of any suitable material providing a strong enough material to
resist impacts, e.g., a metal material or the like.
[0056] The retention pad 610 and washer 620 may have a hole through
which the fastener core member 432, e.g., a bolt, screw, rod, or
the like, of the fastener 430 may pass in a similar to the holes in
the other elements 410, 420, 440, and 450 which allow the bolt 432
to pass through these elements. Moreover, the fastener stop
constraint 630 may be integrated in the fastener core member (e.g.,
a bolt) 432 or otherwise affixed to the fastener core member 432
such that it serves as a stop constraint for the other elements of
the isolation system 600. The washer 620 may provide the retention
pad 610 with protection from impacts with the stop constraint
630.
[0057] A gap 640 is present between the retention pad 610/washer
620 and the stop constraint 630 so as to provide an area where
there is freedom of motion of the elements 610, 620, and 410-450
along the fastener core member 432. This loose configuration allows
all of the elements 410, 420, 440, 450, 610, and 620 to be loosely
coupled to the fastener core member 432 (hereafter using a "bolt"
as an example of element 432) such that they may move to a certain
degree along the long axis of the bolt 432, e.g., in an upward and
downward motion along the bolt 432 depicted in FIG. 6. This
effectively allows the isolation system to vibrate freely and
reduce the amount of vibration transmitted to the palletized
product 460 which is attached to the upper member 420 of the
pallet.
[0058] Because of the configuration of the isolation system 600
elements, the isolation system 600 is a single sided isolation
system where the cushion pad 440 is only compressed and not subject
to tension. The mechanism provides a "single sided spring"
operation in which only a compressive force is exerted upwards on
the cushion pad 440 by the bottom member 450 of the pallet since
the gap 640 provides a freedom of motion that eliminates any
tension force being applied by the upper member 420 on the cushion
pad 440. The gap 640 between the highly damped retention pad 610
and the stop constraint 630 allows the isolation system 600 to
vibrate freely and thus, allows the palletized product 460 to
vibrate with lower amplitude due to less transmissibility.
[0059] In the event that the palletized product 640 starts to tip
due to handling, the upper member 420, and the other elements
410-450 of the isolation system 600 of the pallet moves upward
along a path constrained by the fastener core member 432, pushing
the retention pad 610 and washer 620 upwards until the retention
pad 610 and washer 620 are brought into contact with the stop
constraint 630 to thereby prevent the palletized product from
overturning. Thus, the lower member 450 applies a compressive force
against the cushion pad 440 while the elements above the cushion
pad 440 do not apply a force to the cushion pad 440 until the
cushion pad 440 is pressed against them due to the motion being
stopped by the stop constraint 630. Thus, on both sides, the
cushion pad 440 is only subjected to compressive forces eliminating
the problems associated with known shock pallets where tension
forces may cause the cushion pad to fail and the pallet to break,
resulting in damage to the palletized product and potential injury
or death of individuals involved in the transportation of the
palletized product.
[0060] FIG. 7 is a diagram illustrating a pallet that implements a
load adjusting isolation system of the illustrative embodiments. As
shown in FIG. 7, the pallet 700 is comprised of a plurality of
cushion pad and plunger assemblies 710 sandwiched between a lower
member or deck 720 and an upper member or deck 730 of the pallet
700. The upper member or deck 730 may in fact be provided as
multiple wood beams 732 with a wood decking 734 placed across the
wood beams as shown in FIG. 7 in which case there may be a
plurality of isolation systems provided in association with each of
the wood beams, e.g., two isolation systems for each wood beam
located at the two ends of each beam with the cushion pad and
plunger assemblies 710 being sandwiched between the wood beam of
the upper deck 730 and the lower deck 720 as shown. The retention
pad assemblies 740 comprising the retention pad, washers, gap, and
stop constraint, for each isolation system may be provided above
the wood decking that is placed across the wood beams of the upper
deck 730.
[0061] The palletized product 760 is placed on top of the upper
deck 730 and is fastened to the upper deck 730 by way of fasteners
750, e.g., nut and bolt assemblies with appropriate metal plates to
provide strength of the attachment if necessary. Thus, the
palletized product 760 is fastened to the upper deck 730 such that
if the pallet 700 is tipped this causes an upward force on the
upper deck 730 which closes the gap in the retention pad assemblies
740 on at least one side of the pallet 700 while on the opposite
side of the pallet 700, the gap is increased by a downward force
being applied to the isolation assemblies 710. Thus, on one side of
the pallet, the upward force compresses the retention pad, while on
the other side of the pallet, the downward force likewise
compresses the cushion pad of the isolation system, thereby
avoiding any tension in the cushion pad that might lead to pallet
breakage. Furthermore, the stop constraint prevents the upper deck
730 from coming off of the fasteners of the isolation system and
thereby eliminates the potential for rollover of the palletized
product 760.
[0062] FIG. 8 illustrates the pallet 700 during a tipping
condition, such as may have occurred due to operation of a fork
truck with the pallet 700, movement of the pallet up a ramp or
other incline or grade, motion of a vehicle transporting the pallet
700, or the like. As can be seen from FIG. 8, the palletized
product remains attached to the pallet 700 and the pallet 700 does
not break. Thus, the single sided isolation system with a retention
pad and stop constraint allow for reduced vibration levels in
shipping compared to a conventional shock pallet and still prevent
product overturning.
[0063] It should be appreciated that the above description provides
examples of configurations of the isolation system and load
adapting vibration isolation pallet of the present invention, but
the present invention is not limited to these particular example
configurations. To the contrary, many modifications can be made to
the example configurations without departing from the spirit and
scope of the illustrative embodiments.
[0064] For example, while the above illustrative embodiments
reference the cushion pad as a single pad, the illustrative
embodiments are not limited to such. Rather, the cushion pad may in
fact be comprised of multiple layers of cushioning material, such
as shown in FIG. 9. As shown in FIG. 9, three layers 910-930 of
cushioning material, e.g., neoprene material, are provided with
support plates 940-950 being provided sandwiched between the layers
910-930. The support plates 940-950 may be fashioned from a strong
material such as metal, a strong plastic material, other elastomer
or non-elastomer material, or the like. The layers 910-930
themselves may take on many different configurations of size and
shape. In the depicted example, the layers 910-930 are cushion pad
layers formed in a waffle type configuration in which there are
holes or recesses in the material in a lattice formation.
[0065] As shown in FIG. 9, the plunger assembly 960 may be provided
in the manner previously described above and, as shown in this
example diagram may have many more load distribution elements than
the two previously described above. For example, in the example
depicted in FIG. 9, there are 5 such load distribution elements
shown. Moreover, the fastener core member need not be a bolt as
previously described and in fact may be any fastener core member
with the example shown in FIG. 9 being a threaded screw or bolt.
Although not explicitly shown in the figures, a foam material or
other type of material may be used around the isolation system to
help keep the isolation system properly oriented with regard to the
upper and lower decks of the pallet.
[0066] To further illustrate the possible modifications to the
mechanisms previously described above, while the plunger assembly
has been described as comprising a plurality of load distribution
elements arranged in a stack formation with progressing from
smaller sized load distribution element to larger sized
distribution element, the illustrative embodiments are not limited
to such. Rather, in another illustrative embodiment, the plunger
assembly may be fashioned as one piece rather than separate load
distribution elements configured in a stack formation. FIG. 10
illustrates one example of a single piece plunger assembly in
accordance with this alternative illustrative embodiment.
[0067] As shown in FIG. 10, the plunger assembly 1000 comprises a
cone shaped body 1010 having a substantially flat upper surface
1020 and a substantially flat bottom surface 1030. The
substantially flat bottom surface 1030 is configured to contact and
press into the cushion pad 1050 while the substantially flat upper
surface 1020 is configured to abut and contact the upper member
1060 or deck of the pallet. Thus, as more load is applied to the
pallet, the plunger assembly 1000 is pressed further into the
cushion pad 1050 and more surface area 1040 of the plunger assembly
1000 contacts the cushion pad 1050 thereby increasing the load
bearing area of the plunger assembly 1000 and cushion pad 1050
being used to support the load. Thus, the cone configuration shown
in FIG. 10 performs a similar operation as the stacked
configuration of the plunger assembly previously described above,
but utilizes a single formed piece as opposed to multiple load
distribution elements provided in a stacked formation.
[0068] It should further be appreciated that not only does the
present invention provide the isolation system and load adapting
vibration isolation pallet themselves, but a method of making or
providing such an isolation system and load adapting vibration
isolation pallet. This method may comprise, for example, providing
the lower member or deck of the pallet with a hole or opening
through which the fastener core member may pass and then feeding
the fastener core member through that opening. The cushion pad,
with a similar opening, may be placed on top of the lower member or
deck of the pallet by sliding the cushion pad down the length of
the fastener core member (e.g., bolt) using the opening in the
cushion pad to permit the fastener core member to pass through the
cushion pad.
[0069] In a similar manner, the plunger assembly is placed in
position above the cushion pad. If the plunger assembly is
comprised of a plurality of load distribution elements, each load
distribution element may be individually placed in position above
the cushion pad by sliding them along the fastener core member via
a hole or opening in the load distribution elements (e.g. washers
with center holes with the washers being of increasing diameter).
Thereafter, the upper member may be put into place by providing a
hole in the upper member of the pallet and allowing the fastener
core member to pass through the hole. If no retention pad assembly
is utilized, a stop constraint (e.g., nut) may be used with the
fastener core member to fasten the upper member to the other
elements of the isolation system. If a retention pad assembly is
utilized, the retention pad and washer may then be place above the
upper member or deck of the pallet by similarly sliding them over
the fastener core member using a hole or opening provided in the
retention pad and washer. The stop constraint may then be loosely
fastened to the fastener core member leaving a gap between the stop
constraint and the retention pad assembly.
[0070] Thus, the mechanisms of the illustrative embodiments provide
a load adapting vibration isolation system and pallet for use in
transporting products that are sensitive to vibration and may be
damaged if the pallet is overturned. The mechanisms of the
illustrative embodiments minimize vibration transmissibility in a
problem frequency range by providing an isolation system that
adapts to various loads by way of the use of the novel plunger
assembly and cushion pad configuration described above. Moreover,
the mechanisms of the illustrative embodiments control the
resonance frequency of the isolation system while providing
mechanisms to avoid overturning of the pallet by providing a novel
fastener and retention pad system that allows free vibration of the
isolation system without increasing the transmissibility to the
palletized product.
[0071] The description of the present invention has been presented
for purposes of illustration and description, and is not intended
to be exhaustive or limited to the invention in the form disclosed.
Many modifications and variations will be apparent to those of
ordinary skill in the art without departing from the scope and
spirit of the described embodiments. The embodiment was chosen and
described in order to best explain the principles of the invention,
the practical application, and to enable others of ordinary skill
in the art to understand the invention for various embodiments with
various modifications as are suited to the particular use
contemplated. The terminology used herein was chosen to best
explain the principles of the embodiments, the practical
application or technical improvement over technologies found in the
marketplace, or to enable others of ordinary skill in the art to
understand the embodiments disclosed herein.
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