1. Field of the Invention
This invention pertains to scavenging of power by virtue of human-carried or human-borne devices.
2. Related Art and Other Considerations
It would be highly beneficial if human energy (that would otherwise be wasted) could be scavenged and stored for useful purposes, such as powering electronic devices. For example, a human walking at a normal pace of three mph produces a power output of 233 Watts. Thus, there is a considerable amount of energy that is potentially available to scavenge and use.
There has been considerable interest in the possibility of scavenging human power and either using it directly, or storing it for later use, to power electronic devices. While the interest in the feasibility of this concept was initially generated by the military to power an assortment of electronic equipment carried by a soldier in the field, recent interest in powering portable, personal electronic devices, such as cell phones and MP3 players, is beginning to see interest. See, for example, U.S. Patent Publication 2001/0035723 wherein electroactive polymer devices are used to generate electrical energy by converting mechanical energy generated during by heel strikes during walking into electrical energy.
To date, the problems with scavenging human energy have been summed up in several reports issued by the U.S. United States Office of Naval Research (ONR) and the United States Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO). Thus far, ONR and DARPA DSO have found such devices to date to have one or more of low power output, to be overly complex and/or bulky, and not to be cost effective.
As an example,
Several problems with the
Piezoceramic devices have also been suggested to scavenge footfall energy, energy available from limb motion, and respiratory energy. However, a problem arises with using piezoceramic devices to scavenge energy—fragility of the ceramic itself.
What is needed, therefore, and an object of the present invention, is a human-carried piezogenerator device which is sufficiently rugged to scavenge energy.
An energy scavenging apparatus comprises a frame which can be human-carried or human-borne; plural cantilevered bimorph piezoelectric members connected to the frame to have an essentially parallel orientation, each cantilevered bimorph piezoelectric member comprising a proximal end connected to the frame and a distal end; and, a mass member connected to the distal end of the plural cantilevered bimorph piezoelectric members.
Preferably each of the cantilevered bimorph piezoelectric members are ruggedized laminated piezoelectric devices.
In an example embodiment, the mass member is commonly connected to each of the plural cantilevered bimorph piezoelectric members. As an example implementation of this embodiment, the plural cantilevered bimorph piezoelectric members are connected to opposing sides of the frame in rib fashion, and the distal end of each of the plural cantilevered bimorph piezoelectric members is connected to a sternum-situated central mass member. The central mass member is free-floating except for its suspension attachment to the distal ends of the cantilevered bimorph piezoelectric members. Preferably the central mass member has a mass chosen so that the resonant frequency of the apparatus is be tuned to footfall cadence.
In another example embodiment, each of the plural cantilevered bimorph piezoelectric members has a distinct mass member connected to its distal end. The plural cantilevered bimorph piezoelectric members are connected to opposed sides of the frame in an interleaved fashion. Preferably the mass member of each of the plural cantilevered bimorph piezoelectric members has a mass chosen to tune each of the plural cantilevered bimorph piezoelectric members to a desired resonant frequency to achieve a desired deflection of the distal end of the cantilevered bimorph piezoelectric member.
In another example embodiment, an energy scavenging apparatus comprises a frame which can be human-carried or human-borne; plural piezoelectric members connected to the frame in a manner to cause vibration of the piezoelectric members as a result of human footfall and to generate output power; and, an amplifier for amplifying the vibration of the piezoelectric members.
In the embodiment which comprises an amplifier, as one example, non-limiting implementation the amplifier can comprise nesting frame structures. In such nesting frame structure embodiment, the frame is a bouncing body frame which is resiliently mounted to an outer frame. The bouncing body frame comprises two opposed members to which the plural cantilevered bimorph piezoelectric members are connected. Each of the two opposed members has a guide channel formed therein, with each guide channel being configured to slidably accommodate a guide rod connected to the outer frame. A resilient member is positioned about each guide rod between the bouncing body frame and the outer frame. In one variation of this the nested frame embodiment, the mass member is commonly connected to each of the plural cantilevered bimorph piezoelectric members. In another variation of the nested frame embodiment, each of the plural cantilevered bimorph piezoelectric members has a distinct mass member connected to its distal end. In such variation the plural cantilevered bimorph piezoelectric members can be connected to opposed sides of the frame in an interleaved fashion.
In some example embodiments, the frame is configured to be carried or borne in a manner to excite plural vibrational modes of the plural cantilevered bimorph piezoelectric members, and thereby provide amplification of power provided by the piezoelectric members.
In another example embodiment, at least one of the plural cantilevered bimorph piezoelectric members comprises a non-uniform piezoelectric profile along its length. For example, at least one of the plural cantilevered bimorph piezoelectric member can be piezoelectrically inactive in a region near its proximal end and piezoelectrically active in region near its distal end. As another example, at least one of the plural cantilevered bimorph piezoelectric member can be piezoelectrically active in a region near its proximal end and piezoelectrically active in region near its distal end, but piezoelectrically inactive in a mid-section region between the region near its proximal end and the region near its distal end. As yet another example, at least one of the plural cantilevered bimorph piezoelectric members can comprise a constant stress profile along its length (e.g., be tapered along at least one of its dimensions).
Another example embodiment of an energy scavenging apparatus comprises a housing for defining a chamber; two resilient assemblies positioned proximate respective two ends of the chamber; and, a mass member situated for reciprocating motion in the chamber between the two resilient assemblies. Each of the two resilient assemblies comprises a piezoelectric member which, when deflected by the mass member, produces a voltage and which replies to the reciprocation with a spring force to facilitate further reciprocation. For example, each of the two resilient assemblies can comprise a pair of curved piezoelectric members, with each of the piezoelectric members comprising a concave surface and a convex surface. The two piezoelectric members having their concave surface oriented toward one another and peripheries of their concave surface substantially contacting one another. A convex surface of a first of the piezoelectric members of the pair is oriented toward the mass member and a convex surface of a second of the piezoelectric members of the pair is oriented toward an end of the chamber.
The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of preferred embodiments as illustrated in the accompanying drawings in which reference characters refer to the same parts throughout the various views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.
In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. That is, those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. In some instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. All statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.
In the example embodiment of
Preferably each of the cantilevered bimorph piezoelectric members 30 are ruggedized laminated piezoelectric devices such as those described in one or more of the following (all of which are incorporated herein by reference in their entirety): PCT Patent Application PCT/US01/28947, filed 14 Sep. 2001; U.S. patent application Ser. No. 10/380,547, filed Mar. 17, 2003, entitled “Piezoelectric Actuator and Pump Using Same”; U.S. patent application Ser. No. 10/380,589, filed Mar. 17, 2003; and U.S. Provisional Patent Application, filed Apr. 13, 2005, entitled PIEZOELECTRIC DIAPHRAGM ASSEMBLIES AND METHODS OF MAKING SAME. The ruggedized laminated piezoelectric device has an ability to displace by a larger magnitude than an ordinary piezoceramic, and achieves higher strain rates, without damage. These capabilities allow the ruggedized laminated piezoelectric device to output far greater average power than other piezoelectric devices. In fact, simulations show that an ruggedized laminated piezoelectric device has the potential to output ten times as much power as other similar devices.
In one example implementation, each cantilevered bimorph piezoelectric member 30 of the energy scavenging device 20 of
As thusly described, the technology provides an energy scavenging device comprises a frame which can be inserted or otherwise attached to a human-carried or human-borne item, such as a backpack. Alternatively, the frame can serve as a portion of a frame or skeletal structure for such a human-carried or human-borne item. Plural cantilevered bimorph piezoelectric members are arranged in rib fashion, each cantilevered bimorph piezoelectric member comprising a frame end connected to the frame and a distal end connected to a sternum-situated central mass member. The central mass member is free-floating except for its suspension attachment to the distal ends of the cantilevered bimorph piezoelectric members. The central mass member allows the resonant frequency of the system to be tuned to footfall cadence which would allow for the most efficient energy production. Preferably each of the cantilevered bimorph piezoelectric members are ruggedized laminated piezoelectric devices. The energy scavenging device produces a high power output (relative to comparable devices), and is both simple and inexpensive.
The amplifier structure of an energy scavenging device can take various forms. In the particular implementation of energy scavenging device 120 of
Thus, the energy scavenging device 120 of
The opposing members are illustrated as being parallel, although non-parallel configurations are also possible. The horizontal members 124T and 124B and vertical members 124R and 124L can comprise the outer frame as a type of housing for substantially completely enclosing interior space 126 and components (as subsequently described) therein, the interior region (and thus components therein) can be unbounded in other dimensions so that the frame 122 has an open face and rear face surface in the manner shown in
As previously indicated, the outer frame 122 defines interior space 126. A sliding or bouncing body 130 is situated an interior space 126. The bouncing body 130 itself has a frame (known as the bouncing body frame) which comprises opposing horizontal members 134T and 134B and two opposing vertical members 134R and 134L, which similarly define an interior space 136.
An apertures or guide channel 142 extends entirely through bouncing body 130, and in particularly through opposing vertical members 134R and 134L from top to bottom. The guide channels 142 are slightly spaced away from the vertical sidewalls of bouncing body 130. Each end of both guide channel 142 is fitted with a hollow frictionless bushing 144 or the like. A guide rod 146 extends essentially frictionlessly through each the pair of bushings 144 for each guide channel 142, i.e., guide rod 146L extends through the left guide channel and guide rod 146R extends through the right guide channel. Each guide rod 146 has its top end anchored in members 134T and its bottom end anchored in member 134B. A spring 148 or other resilient member is coiled around bottom ends of each guide rod 146 or is otherwise placed or captured between the member 134B and the lower bushing 144 of bouncing body 130.
The energy scavenging device 120 comprises plural cantilevered bimorph piezoelectric members 150 which extend into sliding body interior space 136. The cantilevered piezoelectric members 150 each have a proximal end anchored into one of the two opposing vertical members 134R and 134L. In the example embodiment of
In an example implementation, each piezoelectric member 150 carries a weighting mass 152 at its distal end. The size and weight of the weighting mass 152 is selected or chosen in accordance with various criteria, such as tuning the piezoelectric members to a desired resonant frequency thus ensuring maximum achievable deflection at the end of the piezoelectric member in relation to a given input excitation. In a variation, the individual piezogenerator members could be tuned to different frequencies to scavenge the most energy from an input that contains multiple frequencies. In other words, the piezogenerator members can be tuned to obtain production of the maximum power output from the device. In one example implementation, the weighting mass 152 is configured as being of spherical shape for sake of illustration, but other geometric shapes are also feasible (e.g., elliptical, rectangular).
Each piezoelectric members 150 has electrodes of its piezoelectric member connected (by unillustrated electrical leads) to an energy collection circuit 160. The energy collection circuit 160 can be carried by or situated on frame 122 or can be remote from frame 122 (e.g., carried elsewhere on a human body or incorporated into an electronic device which is powered by energy scavenging device 120).
In operation, the bouncing body 130 of energy scavenging device 120 slides on guide rods 146, impacting the interior upper and interior bottom surfaces of horizontal members 124T and 124B, respectively, during both upward and downward motion. The bouncing arrangement of bouncing body 130 with respect to frame 122 serves as an amplifier for amplifying the vibration and thus the output power of piezoelectric members, e.g., for causing vibration of the piezoelectric members in many modes.
A conventional energy scavenging device, when worn or carried by a human, may have to operate at a frequency of about 1 Hz. Power output of a energy scavenging device is related to frequency. In some instances a greater power output than that provided by a 1 Hz input may be desired. The energy scavenging devices 120 and 220 of the embodiments of
The bouncing body 130 of the energy scavenging devices 120 and 220 can be set to bounce at a higher frequency that the typical 1 Hz frequency gait of a human. The higher frequency of bouncing body 130 with its multi-mode vibrating piezoelectric members 150 results in generation of more voltage and current by piezoelectric members 150, and thus a higher power output from energy collection circuit 160.
The frequency of the bouncing body 130 can be set by adjusting or setting such parameters as the spring constant of springs 148 and the mass of the bouncing body 130, but in general the springs should be just stiff enough that the bouncing body is allowed to move back and forth thus impacting both of the horizontal frame members 124B and 124T with the given input excitation.
Preferably each of the cantilevered bimorph piezoelectric members 30 are ruggedized laminated piezoelectric devices such as those described in one or more of the following (all of which are incorporated herein by reference in their entirety): PCT Patent Application PCT/US01/28947, filed 14 Sep. 2001; U.S. patent application Ser. No. 10/380,547, filed Mar. 17, 2003, entitled “Piezoelectric Actuator and Pump Using Same”; U.S. patent application Ser. No. 10/380,589, filed Mar. 17, 2003; and U.S. Provisional Patent Application, filed Apr. 13, 2005, entitled PIEZOELECTRIC DIAPHRAGM ASSEMBLIES AND METHODS OF MAKING SAME. The ruggedized laminated piezoelectric device has an ability to displace by a larger magnitude than an ordinary piezoceramic, and achieves higher strain rates, without damage. These capabilities allow the ruggedized laminated piezoelectric device to output far greater average power than other piezoelectric devices. In fact, simulations show that an ruggedized laminated piezoelectric device has the potential to output ten times as much power as other similar devices.
While the preceding discussion has assumed for illustration a bimorph cantilever, other piezoelectric packages such as disks, unimorphs of various geometries, etc., could be utilized as well with the same advantages for a ruggedized laminated piezoelectric device.
One reason for the increased power output of the ruggedized laminated piezoelectric device becomes clear by investigating the equations describing the power output of a typical scavenging device.
In particular, Equation 4 describes the average power output from the device. From Equation 4 it is clear that there are three distinct groups of parameters that affect the power output. A first group of parameters are the geometric properties such as the length (L), width (W), and thickness (T) of the device. These geometric properties are constrained by the allowable dimensions of the device in a particular application. A second group of parameters are the piezoelectric properties of the piezoceramic (e.g., d31 and g31), which are constrained by the choice of piezoceramic. A third group of parameters relates to the loading of the device itself (x{dot over (x)}). From Equation 4, power output of the device is proportional to the product of the displacement and velocity of the device. Therefore, if the device can undergo larger displacements and higher velocities (strain rates) without damage, then the device can output far greater power. The ruggedized laminated piezoelectric device is able to undergo larger displacements and higher velocities (strain rates) without damage, and therefore can generate greater power than a usual piezoceramic device.
Thus, a major advantage of the energy scavenging devices described herein, particularly a energy scavenging device utilizing the ruggedized laminated piezoelectric devices, is increased power output. For the embodiment of
One example application described above is a backpack application, in which frame 22, frame 122, or frame 222 either forms part of a backpack frame or is carried by a backpack (e.g., internally in the backpack or a pocket or compartment of the backpack). The backpack implementation is especially beneficial for military purposes as it allows the energy available from a walking soldier to be scavenged and stored to power the many electronic devices carried by the modern soldier. Besides the backpack application, there are several other potential uses of this technology for scavenging human power. Examples are ruggedized laminated piezoelectric devices placed in shoes or boots to scavenge footfall energy, resonant devices, such as a tuned cantilever, attached (e.g., clip on) to the leg, or arm, or belt, to scavenge energy from limb motion and/or footfall impact, resonant devices built into the heels of shoes or boots, hydraulically driven ruggedized laminated piezoelectric device stacks in shoes or boots, to name a few. The energy scavenging devices can be packaged in a self-contained unit that could be strapped onto a leg, or arm, or belt, of the wearer to scavenge energy from human motion. The energy collection circuits can be carried by the energy scavenging devices themselves, or incorporated into other electronic devices that utilize the energy harvested by the energy scavenging devices.
As mentioned above the backpack device and the footfall devices would be very useful to the military. The strap-on device could conceivably be used to power, or significantly extend the battery life of, personal portable electronic devices such as cell phones or MP3 players.
The cantilever piezoelectric members described in the preceding embodiments can take various forms. For example, the cantilever piezoelectric members need not be piezoelectrically active throughout their entire length. That is, the cantilever piezoelectric members can have a non-uniform piezoelectric profile along their length. Moreover, the non-uniform piezoelectric profile of a piezoelectric member such as a cantilever piezoelectric member as described herein pertains to apparatus including and beyond the human-borne or human-carried embodiments herein described, and is not limited to the human-borne or human-carried embodiments.
In the above regard,
Mounting arrangements such as those shown in
The majority of the stress in a simple cantilever beam is concentrated in an area that is very close to the fixed end. However, a beam can be designed, e.g., profiled, such that the stress is constant along the length of a beam. This can be accomplished by tapering the beam either along its length, or through its thickness, or both.
Thus, constant stress beams (also known as constant stress profiled beams) can be utilized as another means for increasing power output. The majority of the stress in a simple cantilever in concentrated near the fixed end (bend line). Thus little of the piezoceramic is actually producing power.
The profiled beams of
The advantage of using a constant stress beam in piezoelectric energy harvesting application is that most of the piezoceramic material is strained and thus contributes to the power output from the device. This is not the case in a simple cantilever device where the majority of the power output from the device is generated by the piezoceramic material near the fixed end.
To design a constant stress beam, one looks at the equation that describes stress in a beam. The maximum stress in a beam is described by Equation 5.
In Equation 5, M=Fy is moment present at the position along the length of the beam in question, y is the distance from the point of application of the load (the end of the beam in this case) to the position in question, Equation 6 describes the section modulus, b is the beam width, and h is the thickness of the beam.
In an end loaded cantilever beam that is vibrating at a frequency ω the inertial force at the end of the beam where the mass is located is given by Equation 7.
The moment applied to the beam is given by Equation 8, and can be recast as Equation 9.
Since the magnitude of the acceleration {umlaut over (x)} can be written as ω2x the moment becomes as shown in Equation 10.
M=mω2xy Equation 10
Substituting into the stress equation yields Equation 11.
Thus, for the embodiment of
Such constant stress profiled beams can be utilized in any of the embodiments described herein, or any other cantilever piezoelectric device including the piezoelectric devices illustrated in U.S. patent application Ser. No. 10/869,046, entitled “PIEZOELECTRIC GENERATORS AND METHODS OF OPERATING SAME”, which is incorporated herein by reference in its entirety.
In the illustrated example embodiment, each of the resilient assemblies 330 comprises a pair of piezoelectric members, with each of the piezoelectric members comprising a concave surface and a convex surface. The two piezoelectric members have their concave surface oriented toward one another and peripheries of their concave surface substantially contacting one another. A convex surface of a first of the piezoelectric members of the pair is oriented toward the mass member 326 and a convex surface of a second of the piezoelectric members of the pair is oriented toward an end of the chamber 324.
Thus, in an example implementation, each of the resilient assemblies 330 comprises a pair of piezoelectric members arranged in a clamshell or bellows configuration. The juxtaposition or positioning of a pair of piezoelectric members in this manner is understood with reference to, e.g., U.S. patent application Ser. No. 11/024,943, filed Dec. 30, 2004, entitled “PUMPS WITH DIAPHRAGMS BONDED AS BELLOWS” which is incorporated by reference herein in its entirety.
Although in the illustrated embodiment, each side of the tubular housing 320 has four resilient assemblies 330 (e.g., k=4), it will be appreciated that a greater or lesser number (even one) bellows section may be provided on each side of mass member 326. When the energy scavenging device 320 is worn by a walking human, the vibration caused by the human gait causes mass member 326 to reciprocate in housing 322. The reciprocation of mass member 326 causes deflection of the piezoelectric members which comprise the resilient assemblies 330, thereby producing an voltage which is applied through unillustrated leads to one or more energy collection circuits 360. In addition, the flexible properties of resilient assemblies 330 reply to the reciprocation with a spring force to facilitate further reciprocation.
Although various embodiments have been shown and described in detail, the invention is not limited to any particular embodiment or example. None of the above description should be read as implying that any particular element, step, range, or function is essential such that it must be included. It is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements.
This application claims the benefit and priority of U.S. Provisional Patent Application 60/737,809 filed Nov. 18, 2005, entitled “HUMAN POWERED PIEZOELECTRIC POWER GENERATING DEVICE”, and U.S. Provisional Patent Application 60/828,887, filed Oct. 10, 2006, entitled “HUMAN POWERED PIEZOELECTRIC POWER GENERATING DEVICE”, both of which are incorporated herein by reference in their entirety.
Number | Name | Date | Kind |
---|---|---|---|
3230402 | Nightingale et al. | Jan 1966 | A |
3876925 | Stoeckert | Apr 1975 | A |
3936342 | Matsubara et al. | Feb 1976 | A |
3960635 | La Roy et al. | Jun 1976 | A |
3967141 | Gawlick et al. | Jun 1976 | A |
4034780 | Horvath | Jul 1977 | A |
4095615 | Ramsauer | Jun 1978 | A |
4773218 | Wakita et al. | Sep 1988 | A |
4859530 | Roark et al. | Aug 1989 | A |
4927084 | Brandner et al. | May 1990 | A |
4939405 | Okuyama et al. | Jul 1990 | A |
4952836 | Robertson | Aug 1990 | A |
5049421 | Kosh | Sep 1991 | A |
5084345 | Manos | Jan 1992 | A |
5188447 | Chiang et al. | Feb 1993 | A |
5271724 | van Lintel | Dec 1993 | A |
5338164 | Sutton et al. | Aug 1994 | A |
5471721 | Haertling | Dec 1995 | A |
5512795 | Epstein et al. | Apr 1996 | A |
5589725 | Haertling | Dec 1996 | A |
5632841 | Hellbaum et al. | May 1997 | A |
5751091 | Takahashi et al. | May 1998 | A |
5759015 | Van Lintel et al. | Jun 1998 | A |
5811911 | Jänker et al. | Sep 1998 | A |
5814921 | Carroll | Sep 1998 | A |
5816780 | Bishop et al. | Oct 1998 | A |
5835996 | Hashimoto et al. | Nov 1998 | A |
5849125 | Clark | Dec 1998 | A |
5876187 | Afromowitz et al. | Mar 1999 | A |
5909905 | Simpson | Jun 1999 | A |
5945768 | Treu, Jr. | Aug 1999 | A |
6030480 | Face, Jr. et al. | Feb 2000 | A |
6033191 | Kamper et al. | Mar 2000 | A |
6042345 | Bishop et al. | Mar 2000 | A |
6052300 | Bishop et al. | Apr 2000 | A |
6060811 | Fox et al. | May 2000 | A |
6071087 | Jalink, Jr. et al. | Jun 2000 | A |
6071088 | Bishop et al. | Jun 2000 | A |
6074178 | Bishop et al. | Jun 2000 | A |
6104127 | Kameyama et al. | Aug 2000 | A |
6109889 | Zengerle et al. | Aug 2000 | A |
6114797 | Bishop et al. | Sep 2000 | A |
6120264 | Wang | Sep 2000 | A |
6124678 | Bishop et al. | Sep 2000 | A |
6156145 | Clark | Dec 2000 | A |
6162313 | Bansemir et al. | Dec 2000 | A |
6179584 | Howitz et al. | Jan 2001 | B1 |
6194815 | Carroll | Feb 2001 | B1 |
6213735 | Henco et al. | Apr 2001 | B1 |
6227809 | Forster et al. | May 2001 | B1 |
6227824 | Stehr | May 2001 | B1 |
6252336 | Hall | Jun 2001 | B1 |
6257293 | Face, Jr. et al. | Jul 2001 | B1 |
6379809 | Simpson | Apr 2002 | B1 |
6407484 | Oliver et al. | Jun 2002 | B1 |
6411016 | Umeda et al. | Jun 2002 | B1 |
6512323 | Forck et al. | Jan 2003 | B2 |
6734603 | Hellbaum et al. | May 2004 | B2 |
6750596 | Kim et al. | Jun 2004 | B2 |
6751954 | Sewell et al. | Jun 2004 | B2 |
6761028 | Takeuchi et al. | Jul 2004 | B2 |
6869275 | Dante et al. | Mar 2005 | B2 |
6982497 | Rome | Jan 2006 | B2 |
7034440 | Kim et al. | Apr 2006 | B2 |
7070674 | Kelley | Jul 2006 | B2 |
20010035723 | Pelrine et al. | Nov 2001 | A1 |
20020121844 | Ghandi et al. | Sep 2002 | A1 |
20020195823 | Aguire | Dec 2002 | A1 |
20030057618 | Tanner | Mar 2003 | A1 |
20040000843 | East | Jan 2004 | A1 |
20040021398 | East | Feb 2004 | A1 |
20040075363 | Malkin et al. | Apr 2004 | A1 |
20050120527 | Tanielian | Jun 2005 | A1 |
20050206275 | Redzienski et al. | Sep 2005 | A1 |
20050258715 | Schlabach | Nov 2005 | A1 |
20050280334 | Ott et al. | Dec 2005 | A1 |
20060087200 | Sakai | Apr 2006 | A1 |
20060147325 | Vogeley | Jul 2006 | A1 |
20070090723 | Keolian et al. | Apr 2007 | A1 |
Number | Date | Country |
---|---|---|
0 202 836 | Nov 1986 | EP |
2 013 311 | Aug 1979 | GB |
2 161 902 | Jan 1986 | GB |
2 250 911 | Jun 1992 | GB |
2 262 972 | Jul 1993 | GB |
5-39661 | Feb 1993 | JP |
8707218 | Dec 1987 | WO |
0222358 | Mar 2002 | WO |
Number | Date | Country | |
---|---|---|---|
20070145861 A1 | Jun 2007 | US |
Number | Date | Country | |
---|---|---|---|
60828887 | Oct 2006 | US | |
60737809 | Nov 2005 | US |