Patent Application
20130081885
Not Applicable
Not Applicable
This invention relates to the field of personal mobility.
The invention that is disclosed herein is in the field of personal mobility, especially with respect to motorized wheelchairs that can transport a person who is sitting down and gyroscopically-enhanced personal mobility devices that can transport a person who is standing up. Although considerable progress has been made in the past few decades with respect to personal mobility devices, there is still an unmet need for next-generation personal mobility devices that enable a person who cannot walk independently to travel outside during winter months, to travel “off-road” in rustic areas, and to travel up. (and down) staircases independently.
Circular wheels tend to be optimal for traveling over flat, hard, dry surfaces. However, non-circular wheels, such as those with angular protrusions, tend to be optimal for traveling on slippery surfaces and for climbing obstacles such as staircases. There is still an unmet need for a personal mobility device with one or more shape-changing wheels that can transition smoothly and automatically, from having wheels with a circular configuration to having wheels with a non-circular configuration in order to travel more effectively over different surfaces and obstacles. This present invention, a motorized personal mobility device with shape-changing wheels, can meet this need.
It is challenging to classify the prior art into discrete categories, especially when examples of potentially relevant prior art number in the hundreds. However, such classification of the prior art into categories, even if imperfect, is an invaluable tool for reviewing the prior art, identifying the limitations of the prior art, and setting the stage for discussion of the advantages of the present invention in subsequent sections.
Towards this end, I have identified nine general device categories, identified key limitations of devices in these categories, and identified examples of prior art which appear to be best classified into these categories. The nine general categories are: devices with wheels with extendable/retractable spikes/spokes; devices with wheels with differentially inflatable/deformable perimeter segments; devices with wheels with differentially-inflatable parallel adjacent tires; devices with wheels with foldable/bendable perimeter segments; devices with wheels with differentially-expandable concentric rings; devices with compound wheels or multiple interacting circular wheels; devices with multiple interacting non-circular wheels; devices with endless-loop tracks; and devices with walking legs. I also report of a list examples of prior art that appear to be generally relevant to the field of this invention but do not fit neatly into one of these nine categories.
1. Devices with Wheels with Extendable/Retractable Spikes/Spokes
The first category (#1) of relevant prior art includes devices with wheels with spikes/spokes that can be extended outwards from this wheel into contact with the ground (or retracted into the wheel away from contact with the ground): (#1a) in radial manner through holes in the main wheel perimeter; (#1b) in a non-radial angular manner (as with a spider wheel) through holes in the main wheel perimeter; (#1c) in a radial manner through an opening between two parallel wheels; (#1d) in a non-radial angular manner (as with a spider wheel) through an opening between two parallel wheels; (#1e) in a radial manner from a mechanism on the side of a wheel; (#1f) in a laterally-rotating manner from a mechanism on the side of a wheel; (#1g) in a non-radial angular manner (as with a spider wheel) from a mechanism on the side of a wheel; or (#1h) in a radial manner, unaccompanied by any main wheel perimeter. I now discuss the limitations of devices in each of these sub-categories.
For devices in sub-category #1a: there are limitations on the number and width of spikes/spokes because numerous or large holes in the main wheel perimeter weaken the structure of the main wheel perimeter; there are limitations on the length of spikes/spokes because long radial spikes tend to jam when retracted into the wheel; there are limitations on the shape of spikes/spokes (straight or tapered) that extend out in a radial manner; and there is discontinuity in frictional contact with the ground when the spikes/spokes are extended which can cause loss of control when the device is moving. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #1a—wheels with spikes/spokes that can be extended outwards from the wheel into contact with the ground in radial manner through holes in the main wheel perimeter: U.S. Pat. No. 2,174,944 (Leggett, Nov. 16, 1937, “Vehicle Wheel Traction Means”); U.S. Pat. No. 2,250,713 (Johnson, Jul. 19, 1940, “Auxiliary Traction Device”); U.S. Pat. No. 2,924,486 (Blaschke, Aug. 13, 1956, Traction Increasing and Safety Device”); U.S. Pat. No. 3,239,277 (Beck, Mar. 4, 1964, “Traction Structure for Motor Vehicles”); U.S. Pat. No. 4,601,519 (Andrade et al., Jul. 22, 1986, “Wheel with Extendable Traction Spikes and Toy Including Same”); and U.S. Pat. No. 5,029,945 (Kidwell at al., Jul. 9, 1991, “Vehicular Traction Wheel”).
For devices in sub-category #1b: there are limitations on the number and width of spikes/spokes because numerous or large holes in the main wheel perimeter weaken the structure of the main wheel perimeter; there are limitations on the number of spikes/spokes because long spikes/spokes will overlap and jam when retracted into the wheel; and there is discontinuity in frictional contact with the ground when the spikes/spokes are extended which can cause loss of control when the device is moving. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #1b—wheels with spikes/spokes that can be extended outwards from the wheel into contact with the ground in a non-radial angular manner, as with a spider wheel, through holes in the main wheel perimeter: U.S. Pat. No. 1,408,885 (Humphrey, Mar. 7, 1922, “Tractor Wheel”); U.S. Pat. No. 2,044,812 (Roessel, Jun. 8, 1935, “Antiskidding Device for Automobiles”); U.S. Pat. No. 2,818,301 (Hayden, Nov. 20, 1956, “Retractable Tractor Wheel Land Grips”); U.S. Pat. No. 4,266,832 (Delaunay et al., May 12, 1981, “Vehicle Wheel Anti-Slip Device”); U.S. Pat. No. 4,547,173 (Jaworski et al., Oct. 15, 1985, “Toy Vehicle Claw Wheel”); U.S. Pat. No. 4,643,696 (Law, Feb. 17, 1987, “Vehicle Wheel with Clutch Mechanism and Self Actuated Extending Claws”); U.S. Pat. No. 4,648,853 (Siegfried, Mar. 10, 1987, “Wheel Hub Locking Mechanism”); and U.S. Pat. No. 6,561,320 (Yi, May 13, 2003, “Automatically Operated Antiskid Apparatus For Automobile Tires”).
For devices in sub-category #1c: there are limitations on how narrow the combined wheel structure (including two parallel wheels) can be, which is problematic for applications for which wide tires (and wide turning radii) are not acceptable; there are gaps between the spikes/spokes, between the two wheels, which can become clogged with debris in all configurations; and there is discontinuity in frictional contact with the ground when the spikes/spokes are extended which can cause loss of control for the device. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #1c—wheels with spikes/spokes that can be extended outwards from the wheel into contact with the ground in a radial manner through an opening between two parallel wheels: U.S. Pat. No. 5,788,335 (O'Brien, Aug. 4, 1998, “Traction Device for Vehicle Wheels”); U.S. Pat. No. 5,810,451 (O'Brien, Sep. 22, 1998, “Traction Device for Vehicle Wheels”); U.S. Pat. No. 6,022,082 (O'Brien, Feb. 8, 2000, “Traction Device for Vehicle Wheels”); U.S. Pat. No. 6,244,666 (O'Brien, Jun. 12, 2001, “Traction Device for Vehicle Wheels”); and U.S. Pat. No. 6,386,252 (O'Brien, May 14, 2002, “Traction Device for Vehicle Wheels”).
For devices in sub-category #1d: there are limitations on how narrow the combined wheel structure (including two parallel wheels) can be, which is problematic for applications for which wide tires (and wide turning radii) are not acceptable; there are limitations on the number of spikes/spokes because too many spikes/spokes will overlap and jam when retracted into the wheel; there are gaps between the spikes/spokes, between the two wheels, which can become clogged with debris in extended configurations; and there is discontinuity in frictional contact with the ground when the spikes/spokes are extended which can cause loss of control when the device is moving. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations. Although categorization of prior art can be imprecise, the following seems to be an example of prior art that can be best classified into sub-category #1d—wheels with spikes/spokes that can be extended outwards from the wheel into contact with the ground in a non-radial angular manner, as with a spider wheel, through an opening between two parallel wheels: U.S. Pat. No. 8,007,341 (Su, Aug.30, 2011, “Wheel Assembly for Toy Car”).
For devices in sub-category #1e: there are limitations on how narrow the combined wheel structure (including the structure attached to the side of the wheel) can be, which is problematic for applications for which wide tires (and wide turning radii) are not acceptable; there are limitations on the number of spikes/spokes because too many spikes/spokes will overlap and jam when retracted into the wheel; and there is discontinuity in frictional contact with the ground when the spikes/spokes are extended which can cause loss of control when the device is moving. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #1e—wheels with spikes/spokes that can be extended outwards from the wheel into contact with the ground in a radial manner from a mechanism on the side of a wheel: U.S. Pat. No. 1,319,018 (Oatsdean, Oct. 14, 1919, “Traction Device for Motor Vehicles”); U.S. Pat. No. 3,356,171 (Cichetti, Jun. 7, 1964, “Traction Assistance Device”); U.S. Pat. No. 3,458,236 (Winsen, Jul. 19, 1967, “Traction Increasing Wheel”); U.S. Pat. No. 4,193,466 (Arbderman, Mat. 18, 1980, “Traction-Enhancing Device for Automotive Vehicle Drive Wheels”); U.S. Pat. No. 4,909,576 (Zampieri, Mar. 20, 1990, “Antiskid Device for Motor Vehicles”); U.S. Pat. No. 7,380,618 (Gunderson et al., Jun. 3, 2088, “Stair Climbing Platform Apparatus and Method”); and U.S. Pat. No. 7,806,208 (Gunderson et al., Oct. 5, 2010, “Stair Climbing Platform Apparatus and Method”).
For devices in sub-category #1f: there are limitations on how narrow the combined wheel structure can be (including sufficient side space for lateral rotation of the spikes or other projections), which is problematic for applications for which wide tires (and wide turning radii) are not acceptable; and there is discontinuity in frictional contact with the ground when the spikes/spokes are extended which can cause loss of control when the device is moving. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #1f—wheels with spikes or other projections that can be extended outwards from the wheel into contact with the ground in a laterally-rotating manner from a mechanism on the side of a wheel: U.S. Pat. No. 3,861,752 (Thurre at al., Jan. 21, 1975, “Anti-Skid Device for Wheeled Vehicles”); U.S. Pat. No. 4,120,336 (Baskall, Oct. 17, 1978, “Traction Device for Power Driven Vehicles”); U.S. Pat. No. 4,508,150 (Granryd, Apr. 2, 1985, “Retractable Traction Intensifying Means for Agricultural Tractors and the Like”); U.S. Pat. No. 4,603,916 (Granryd, Aug. 5, 1986, “Lightweight Retractable Track-Wheel for Agricultural Tractors and the Like”); U.S. Pat. No. 5,540,267 (Rona, Jul. 30, 1996, “Traction Device for Wheeled Vehicles”); U.S. Pat. No. 6,502,657 (Kerrebrock et al., Jan. 7, 2003, “Transformable Vehicle”); U.S. Pat. No. 6,860,346 (Burt et al., Mar. 1, 2005, “Adjustable Diameter Wheel Assembly and Methods and Vehicles Using Same”); U.S. Pat. No. 7,174,935 (Kahen, Feb. 13, 2007, “Automatic Safety Tire Device”); U.S. Pat. No. 7,217,170 (Moll et al., May 15, 2007, “Transformable Toy Vehicle”); U.S. Pat. No. 7,448,421 (Kahen, Nov. 11, 2008, “Safety Traction Device”); and U.S. Pat. No. 7,794,300 (Moll et al., Sep. 14, 2010, “Transformable Toy Vehicle”); and U.S. patent application 20040000439 (Burt et al., Jan. 1, 2004, “Adjustable Diameter Wheel Assembly, and Methods and Vehicles Using Same”).
For devices in sub-category #1g: there are limitations on how narrow the combined wheel structure can be (including the structure attached to the side of the wheel), which is problematic for applications for which wide tires (and wide turning radii) are not acceptable; there are gaps between the spikes/spokes which can become clogged with debris, and there is discontinuity in frictional contact with the ground when the spikes/spokes are extended which can cause loss of control when the device is moving. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #1g—wheels with spikes/spokes that can be extended outwards from the wheel into contact with the ground in a non-radial angular manner, as with a spider wheel, from a mechanism on the side of a wheel: U.S. Pat. No. 3,995,909 (van der Lely, Dec. 7, 1976, “Vehicle Anti-Skid Mechanisms”); U.S. Pat. No. 4,906,051 (Vilhauer Jr., Mar. 6, 1990, “Easily Activated and Deactivated Traction Device for Vehicles”); U.S. Pat. No. 6,752,400 (Nakatsukasa et al., Jun. 22, 2004, “Moving Unit”); and U.S. Pat. No. 7,837,201 (Cheng et al., Nov. 23, 2010, “Assistant Apparatus for Surmounting Barrier”).
For devices in sub-category #1h: spikes/spokes without a main wheel perimeter cause a bumpy ride on flat, hard surfaces; and there are gaps between the spikes/spokes which can become clogged with debris. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations. Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #1h—wheels with spikes/spokes that can be extended outwards from the wheel into contact with the ground in a radial manner, unaccompanied by any main wheel perimeter: U.S. Pat. No. 6,402,161 (Baghdadi, Jun. 11, 2002, “Portable Stair-Climbing Load Transporting Dolly”); and U.S. Pat. No. 7,503,567 (Frankie, Mar. 17, 2009, “Automated Wheelchair”); and U.S. patent application 20080251300 (Frankie, Oct. 16, 2008, “Automated Wheelchair”).
2. Devices with Wheels with Differentially Inflatable/Deformable Perimeter Segments
The second category (#2) of relevant prior art includes devices with wheels with differentially inflatable/deformable perimeter segments. Differential inflation or deformation of different portions of a wheel's perimeter can change the shape of the wheel. This category includes devices with: (#2a) a tire with differential inflation of different perimeter segments; and (#2b) a tire with inner pistons or spokes that deform an elastic perimeter. I will now discuss the limitations of devices in these sub-categories.
For devices in sub-category #2a: there are constraints on how angular one can make a wheel perimeter based on differential inflation of perimeter segments. The resulting shapes are rounded and not well-suited for climbing stair treads or for traction on ice. Also, whenever segment inflation or deflation is required to change the shape of a wheel, there are limitations on how fast the shape can be changed in response to unexpected changes in surface conditions or obstacles. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations. Although categorization of prior art can be imprecise, the following seems to be an example of prior art that can be best classified into sub-category #2a—a device with a tire with differential inflation of different perimeter segments: U.S. Pat. No. 6,725,895 (Tsipov, Apr. 27, 2004, “Wheel”).
For devices in sub-category #2b: there are constraints on how angular one can make a wheel perimeter based on deformation of a pneumatic (or other elastic) wheel perimeter using inner pistons or spokes. The resulting shapes are rounded and not well-suited for climbing stair treads or for traction on ice. Also, repeated deformation of a pneumatic (or other elastic) perimeter can cause material fatigue and structural failure. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #2b—a device with a tire with inner pistons or spokes that deform an elastic perimeter: U.S. Pat. No. 5,407,054 (Matsuda et al., Apr. 18, 1995, “Roller of Variable Outer Diameter Type, and Carrying Apparatus and Method using the Same”); U.S. Pat. No. 5,480,022 (Matsuda et al., Jan. 2, 1996, “Roller of Variable Outer Diameter Type, and Carrying Apparatus and Method using the Same”); U.S. Pat. No. 5,839,795 (Matsuda et al., Nov. 24, 1998, “Variable Outer Diameter Wheel for Vehicles”); U.S. Pat. No. 6,264,283 (Rehkemper et al., Jul. 24, 2001, “Adjustable Wheel for Toy Vehicles”); U.S. Pat. No. 7,594,527 (Thompson, Sep. 29, 2009, “Wheel Cover System”); and U.S. Pat. No. 8,020,944 (Thompson, Sep. 20, 2011, “Wheel System with Deformable Tire”); and U.S. patent application 20110127732 (Mann et al., Jun. 2, 2011, “Stair Climbing Wheel with Multiple Configurations”).
3. Devices with Wheels with Differentially-Inflatable Parallel Adjacent Tires
The third category (#3) of relevant prior art includes devices with compound wheels that include two or more parallel, adjacent, and differentially-inflatable tires. Differential inflation of parallel tires with different traction characteristics can change which of the tires is in contact with the ground at a given time. When the different tires have different traction properties, this can provide changes in traction in response to different travel surfaces. For devices in category #3, the requirement of having multiple parallel adjacent tires means that this approach does not work for applications in which wide tires (and wide turning radii) are not acceptable. Also, for devices in category #3, there are constraints on how angular one can make a wheel perimeter. Tire shapes tend to be rounded and not well-suited for climbing stair treads or for traction on ice. Also, whenever segment inflation or deflation is required, there are limitations on how fast a device can change which tire contacts the ground in response to unexpected changes in surface conditions or obstacles. The invention which I will disclose herein offers advantages over prior art in this category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into category #3—two or more parallel and adjacent tires with differential inflation: U.S. Pat. No. 6,615,888 (Elkow, Sep. 9, 2003, “Variable-Diameter Wheel-and-Tire Apparatus for Motor Vehicles”); U.S. Pat. No. 6,637,834 (Elkow, Oct. 28, 2003, “Variable-Diameter Wheel Apparatus for Motor Vehicles”); and U.S. Pat. No. 6,733,088 (Elkow, May 11, 2004, “Variable-Diameter Wheel Apparatus for Motor Vehicles”).
4. Devices with Wheels with Foldable/Bendable Perimeter Segments
The fourth category (#4) of relevant prior art includes wheels with foldable or bendable perimeter segments. This category includes devices with: (#4a) wheels with perimeter segments that fold or bend inward; (#4b) wheels with perimeter segments that fold or bend outward; and (#4c) wheels with radial expansion of two or more perimeter segments outwards along a single mid-segment axis. I will now discuss the limitations of devices in these sub-categories.
Devices in sub-category #4a have perimeter segments that can become structurally weak due to repeated folding or bending. Also, for many devices in #4a, the process for restoring a perimeter to its pre-deformation (e.g. circular) shape is either a manual one or is not well specified. If a circular shape is automatically restored by outward pressure from elastic members in the wheel, then this outward pressure could cause undesirable loss of engagement with the travel surface. For example, a circular wheel that becomes non-circular in response to encountering a staircase due to deformation of an elastic member within the wheel could “pop out” again into circular shape when the device is mid-way up the staircase, with dire consequences for the person being transported. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations. Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #4a—wheel with perimeter segments that fold or bend inward: U.S. Pat. No. 3,179,431 (Pikl, Jan. 29, 1963, “Obstacle-Climbing Wheel Chairs”); and U.S. Pat. No. 3,226,129 (McKinley, Nov. 4, 1963, “Vehicle and. Deformable Wheel Thereof”); and U.S. patent application 20010030402 (White, Oct. 18, 2001, “All-Terrain Wheeled Vehicle”).
Devices in sub-category #4b have perimeter segments that can become structurally weak or fail due to repeated folding or bending. Also, for some devices in #4b, the process for restoring a perimeter to its pre-deformation (e.g. circular) shape is not well specified. If a circular shape is automatically restored by, inward pressure from a travel surface on elastic members, then this inward pressure could cause undesirable loss of engagement with the travel surface. For example, a wheel that becomes non-circular in response to encountering a staircase could “pop inwards” again into a circular shape when the device is mid-way up the staircase, with dire consequences for the person being transported. Also, in #4b devices there are gaps between segments of the wheel perimeter that fold or bend outwards. These gaps may become clogged with debris and prevent the wheel from returning to a circular configuration. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations. Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #4b—wheel with perimeter segments that fold or bend outward: U.S. Pat. No. 4,773,889. (Rosenwinkel et al., Sep. 27, 1988, “Wheel for a Toy Vehicle”); and U.S. Pat. No. 5,487,692 (Mowrer et al., Jan. 30, 1996, “Expandable Wheel Assembly”).
Devices in sub-category #4c have gaps between segments of the wheel perimeter that extend radially outwards along a single mid-segment axis. These gaps may become clogged with debris and prevent the wheel from returning to a circular configuration. There are also constraints on the shapes that such radial extension can create. For example, radial extension of two halves of a wheel creates an overall oblong shape. Radial extension of three thirds of a wheel creates a rounded triangular shape. These rounded shapes may not offer the variation in shape configuration that is required to climb up or over various obstacles, such as a staircase. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations. Although categorization of prior art can be imprecise, the following seems to be an example of prior art that can be best classified into sub-category #4c—wheel with radial expansion of perimeter segments outwards along a single mid-segment axis: U.S. Pat. No. 5,102,367 (Mullaney et al., Apr. 7, 1992, “Toy Vehicle Wheel and Axle Assembly”).
5. Devices with Wheels with Differentially-Expandable Concentric Rings
The fifth category (#5) of relevant prior art includes devices with a wheel with differentially-expandable (e.g. inflatable) concentric rings. For example, there can be an inner tire with an uneven perimeter and an outer inflatable ring with a smooth perimeter around that inner tire. When the outer ring is inflated, then the wheel has a smooth outer perimeter. When the outer ring is deflated, it collapses onto the inner tire and the wheel has an uneven outer perimeter. Devices in category #5 have limitations. For example, the impact of the inner tire surface is limited because it is dampened by the surface of the deflated outer ring when the outer ring is deflated. Also, there are limits to how quickly the outer ring can be deflated in response to unexpected changes in the surface or obstacles that the device encounters. Also, the inner surface, which would be used to provide greater traction, is smaller in diameter than the outer ring, which is counter-productive for traction. The invention which I will disclose herein offers advantages over prior art in this category because it does not have these limitations. Although categorization of prior art can be imprecise, the following seems to be an example of prior art that can be best classified into category #5—device with a wheel with differentially-expandable concentric rings: U.S. Pat. No. 4,919,489 (Kopsco, Apr. 24, 1990, “Cog-Augmented Wheel for Obstacle Negotiation”).
6. Devices with Compound Wheels or Multiple Interacting Circular Wheels
The sixth category (#6) of relevant prior art includes devices with composite wheels (such as rotating configurations of multiple wheels) or multiple interacting circular wheels. Such wheel configurations can enhance a device's surface traveling or obstacle-climbing ability. Devices in category #6 are generally, perhaps even universally in the prior art, comprised of multiple circular wheels. Circular wheels do not provide the angular shapes that are needed for traction on surfaces such as ice or snow, even when they are used in multi-wheel configurations. Devices in #6 have limited grasping and hooking ability for climbing up, or over, obstacles. Also, devices in #6 do not provide the simplicity, speed, and smooth ride of a single large wheel for traveling on flat, hard surfaces. The invention which I will disclose herein offers advantages over prior art in this category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into category #6—devices with composite wheels (such as rotating configurations of multiple wheels) or multiple interacting circular wheels: U.S. Pat. No. 4,512,588 (Cox, Apr. 23, 1985, “Stair Climbing Wheel Chair”); U.S. Pat. No. 4,674,757 (Martin, Jun. 23, 1987, “Stair-Climbing Wheel Utilizing an Involute Curve Configuration”); U.S. Pat. No. 4,709,772 (Brunet, Dec. 1, 1987, “Motorized Moving Device”); U.S. Pat. No. 4,790,548 (Decelles et al., Dec. 13, 1998, “Climbing and Descending Vehicle”); U.S. Pat. No. 4,993,912 (King et al., Feb. 19, 1991, “Stair Climbing Robot”); U.S. Pat. No. 5,273,296 (Lepek, Dec. 28, 1993, “Obstacle Overcoming Vehicle Suspension System”); U.S. Pat. No. 5,701,965 (Kamen et al., Dec. 30, 1997, “Human Transporter”); U.S. Pat. No. 5,964,473 (Degonda et al., Oct. 12, 1999, “Wheelchair for Transporting or Assisting the Displacement of at Least One User Particularly for Handicapped Person”); U.S. Pat. No. 5,971,091 (Kamen et al., Oct. 26, 1999, “Transportation Vehicles and Methods”); U.S. Pat. No. 6,311,794 (Morrell et al., Nov. 6, 2001, “System and Method for Stair Climbing in a Cluster-Wheel Vehicle”); U.S. Pat. No. 6,343,664 (Morrell et al., Feb. 5, 2002, “Operating Modes for Stair Climbing in a Cluster-Wheel Vehicle”); U.S. Pat. No. 6,443,251 (Morrell et al., Sep. 3, 2002, “Methods for Stair Climbing in a Cluster-Wheel Vehicle”); U.S. Pat. No. 6,484,829 (Cox, Nov. 26, 2002, “Battery Powered Stair-Climbing Wheelchair”); U.S. Pat. No. 6,615,938 (Morrell et al., Sep. 9, 2003, “Mechanism for Stair Climbing in a Cluster-Wheel Vehicle”); U.S. Pat. No. 6,799,649 (Kamen et al., Oct. 5, 2004, “Control of a Balancing Personal Vehicle”); U.S. Pat. No. 7,040,429 (Molnar, May 9, 2006, “Wheelchair Suspension”); U.S. Pat. No. 7,055,634 (Molnar, Jun. 6, 2006, “Wheelchair suspension”); U.S. Pat. No. 7,066,290 (Fought, Jun. 27, 2006, “Wheelchair Suspension Having Pivotal Motor Mount”); U.S. Pat. No. 7,219,755 (Goertzen et al., May 22, 2007, “Obstacle Traversing Wheelchair”); U.S. Pat. No. 7,374,002 (Fought, May 20, 2008, “Wheelchair Suspension”); U.S. Pat. No. 7,426,970 (Olsen, Sep. 23, 2008, “Articulated Wheel Assemblies and Vehicles Therewith”); and U.S. Pat. No. 7,784,569 (Cheng et al., Aug. 31, 2010, “Barrier-Overpassing Transporter”); and U.S. patent application 20070152427 (Olsen, Jul. 5, 2007, “Articulated Wheel Assemblies and Vehicles Therewith”).
7. Devices with Multiple Interacting Non-Circular Wheels
The seventh category (#7) of relevant prior art includes devices with multiple non-circular interacting wheels that function in series or in parallel. Wheels that function in series rotate around sequential axes. Wheels that function in rotate around the same axis. Multiple non-circular wheels can function as non-circular wheels when they rotate in a synchronized manner, but can collectively mimic circular wheels when they rotate in an asynchronous manner. This category includes devices with: (#7a) multiple interacting non-circular wheels that are configured in series; and (#7b) multiple interacting non-circular wheels that are configured in parallel. I will now discuss the limitations of devices in these sub-categories in detail.
Devices in sub-category #7a do not provide the simplicity, speed, and smooth ride of a single large wheel when traveling on flat, hard surfaces. Also, devices in sub-category #7a require multiple wheels. This increases the weight of the device and limits its turning radius. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations. Although categorization of prior art can be imprecise, the following seems to be an example of prior art that can be best classified into sub-category #7a—devices with multiple interacting non-circular wheels that are configured in series: U.S. Pat. No. 6,604,589 (Sepitka, Aug. 12, 2003, “Drive for a Vehicle Intended to Transverse Rough Terrain”).
Devices in sub-category #7b do not provide the simplicity, speed, and smooth ride of a single large wheel when traveling on flat, hard surfaces. Devices in sub-category #7b also require multiple parallel adjacent wheels. This is not feasible for applications that cannot accommodate wide wheels. The invention which I will disclose herein offers advantages over the prior art because it does not have these limitations. Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #7b—devices with multiple interacting non-circular wheels that are configured in parallel: U.S. Pat. No. 5,971,091 (Kamen et al., Oct. 26, 1999, “Transportation Vehicles and Methods”); and U.S. Pat. No. 7,749,033 (Paulus, Jul. 6, 2010, “Amphibious Surface Vehicle with Synchro-Phased Rotary Engagement Devices”); and U.S. patent application 20100159757 (Paulus, Jun. 24, 2010, “Amphibious Surface Vehicle with Synchro-Phased Rotary Engagement Devices”).
8. Devices with Endless-Loop Tracks
The eighth category (#8) of relevant prior art includes devices with an “endless-loop” track that goes around two or more inner wheels, like the endless-loop tracks used in military tanks. This category includes: (#8a) devices with only an endless-loop track that goes around two or more inner wheels whose positions are fixed relative to each other; (#8b) devices with only an endless-loop track that goes around two or more inner wheels whose positions can be moved relative to each other; (#8c) devices with simultaneous operation of both an endless-loop track and surface-contacting wheels; and (#8d) devices with adjustable selection of either an endless-loop track or surface-contacting wheels. I will now discuss the limitations of devices in these sub-categories in detail.
Sub-category #8a devices tend to be heavy due to the multiple inner wheels and the weight of the track. Heavy devices consume more energy, deplete battery life, are dangerous to the person if they tip over, and are difficult to move in the event of motor failure or battery failure. Also, for sub-category #8a devices it is difficult to create tracks with projections that are sufficiently long and stiff to provide safe and secure engagement with step treads for climbing staircases. Track projections on such devices tend to be short and/or flexible, which can be insufficient to safely grasp stairs. If the heavy device slips, it can topple down the stairs and crush the person being transported. Also, sub-category #8a devices do not provide a large circular wheel for smooth, rapid travel over a flat, hard surface. A fourth problem is that such devices have a relatively wide turning radius, making them difficult to maneuver in indoor settings such as an office or store. Finally, some people may not like the “tank-like” appearance of such devices. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #8a—devices with only an endless-loop track that goes around two or more inner wheels whose positions are fixed relative to each other: U.S. Pat. No. 3,869,011 (Jensen, Mar. 4, 1975, “Stair Climbing. Tracked Vehicle”); U.S. Pat. No. 4,077,483 (Randolph, Mar. 7, 1978, “Invalid Vehicle”); U.S. Pat. No. 5,123,495 (Littlejohn et al., Jun. 23, 1992, “Wheelchair Stair Climbing Control System”); U.S. Pat. No. 5,248,007 (Watkins et al., Sep. 28, 1993, “Electronic Control System for Stair Climbing Vehicle”); U.S. Pat. No. 5,577,567 (Johnson et al., Nov. 26, 1996, “Stair Climbing Wheelchair”); U.S. Pat. No. 5,676,215 (Misawa, Oct. 14, 1997, “Stair-Climbing Crawler Transporter”); U.S. Pat. No. 6,250,409 (Wells, Jun. 26, 2001, “Multi-Point Mobility Device”); U.S. Pat. No. 6,604,590 (Foulk Jr., Aug. 12, 2003, “Battery Powered All-Terrain Vehicle for the Physically Challenged”); and U.S. Pat. No. 6,619,414 (Rau, Sep. 16, 2003, “Personal Mobility Vehicle”); and U.S. patent application 20110011652 (Swensen, Jan. 20, 2011, “Multi-Terrain Motorized Wheelchair Apparatus”).
Sub-category #8b devices also tend to be heavy due to the multiple inner wheels and the weight of the track. Also, sub-category #8a devices do not provide a large circular wheel for smooth, rapid travel over a flat, hard surface. Also, they have a relatively wide turning radius, making them difficult to maneuver in indoor settings. Further, for devices in sub-category #8b, it is difficult to create an endless-loop track that can vary in length without mechanical failures and breakage. If one makes an endless-loop track that can stretch, then it can slip on the gear mechanisms that drive it and can suffer material fatigue and breakage. If one makes an endless-loop track that cannot stretch, then one needs a mechanism for storing slack and maintaining tension in smaller-perimeter configurations. Such storage mechanisms can be complex and, if they involve a combination of convex and concave loops, can easily be clogged by debris on the track. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #8b—devices with only an endless-loop track that goes around two or more inner wheels whose positions can be moved relative to each other: U.S. Pat. No. 3,459,454 (Liston, Aug. 7, 1967, “Elliptical Wheel”); U.S. Pat. No. 3,712,359 (Williams, Jan. 23, 1973, “Crazy Tires”); U.S. Pat. No. 3,802,743 (Hermanns, Apr. 9, 1974, “Variable Diameter Wheel”); U.S. Pat. No. 4,046,339 (Stancliffe, Sep. 6, 1977, “Landing Gear for an Aircraft Including Expansible Wheels”); U.S. Pat. No. 4,194,584 (Kress et al., Mar. 25, 1980, “Variable. Terrain Vehicle”); U.S. Pat. No. 5,423,563 (Wild, Jun. 13, 1995, “Wheelchair Having Apparatus for Climbing Stairs”); U.S. Pat. No. 5,492,390 (Kugelmann Sr., Feb. 20, 1996, “Variable Shaped Wheel”); U.S. Pat. No. 6,422,576 (Michaeli et al., Jul. 23, 2002, “Transport Mechanism”); U.S. Pat. No. 7,334,850 (Spector et al., Feb. 26, 2008, “Adaptable Traction System of a Vehicle”); and U.S. Pat. No. 7,547,078 (Spector et al., Jun. 16, 2009, “Adaptable Traction System of a Vehicle”); and U.S. patent applications 20050127752 (Spector et al., Jun. 16, 2005, “Adaptable Traction System of a Vehicle”); 20080061627 (Spector et al., Mar. 13, 2008, “Adaptable Traction System of a Vehicle”); and 20090212623 (Spector et al., Aug. 27, 2009, “Adaptable Traction System of a Vehicle”).
Sub-category #8c devices also tend to be heavy because not only do they have the multiple inner wheels and a track, but they have regular wheels as well. Also, for sub-category #8c devices it is difficult to create tracks with projections that are sufficiently long and stiff to provide safe and secure engagement with step treads for climbing staircases. Track projections on such devices tend to be short and/or flexible, which can be insufficient to safely grasp stairs. If the heavy device slips, it can topple down the stairs and crush the person being transported. Also, sub-category #8c devices do not provide a circular wheel for smooth, rapid travel over a flat, hard surface. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations. Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #8c—devices with simultaneous operation of both an endless-loop track and surface-contacting wheels: U.S. Pat. No. 4,898,256 (Lehner, Feb.6, 1990, “Stair-Climbing Wheelchair Carrier with Crawlers”); U.S. Pat. No. 5,395,129 (Kao, Mar. 7, 1995, “Wheel Chair”); and U.S. Pat. No. 7,597,163 (Goertzen et al., Oct. 6, 2009, “Obstacle Traversing Wheelchair”).
Sub-category #8d devices also tend to be heavy because not only do they have the multiple inner wheels and a track, but they have regular wheels as well. Also, for sub-category #8d devices it is difficult to create tracks with projections that are sufficiently long and stiff to provide safe and secure engagement with step treads for climbing staircases. Track projections on such devices tend to be short and/or flexible, which can be insufficient to safely grasp stairs. Further, there are limitations on how quickly such a device can be transitioned from endless-loop track to wheels, or vice versa, in response to unexpected changes in the type of travel surface or surface obstacles. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #8d—devices with adjustable selection of either an endless-loop track or surface-contacting wheels: U.S. Pat. No. 4,044,850 (Winsor, Aug. 30, 1977, “Wheelchair”); U.S. Pat. No. 4,119,163 (Ball, Oct. 10, 1978, “Curb Climbing Wheel Chair”); U.S. Pat. No. 4,432,425 (Nitzberg, Feb. 21, 1984, “Wheel Chair”); U.S. Pat. No. 4,566,551 (Feliz, Jan. 28, 1986, “Stair-Climbing Conveyance”); U.S. Pat. No. 4,566,707 (Nitzberg, Jan. 28, 1986, “Wheel Chair”); U.S. Pat. No. 4,674,584 (Watkins, Jun. 23, 1987, “Stair-Climbing Wheelchair with Stair Step Sensing Means”); U.S. Pat. No. 4,687,068 (Pagett, Aug. 18, 1987, “Invalid's Wheelchair and Like Conveyances”); U.S. Pat. No. 4,962,941 (Rembos, Oct. 16, 1990, “Wheelchair Apparatus”); U.S. Pat. No. 5,335,741 (Rabinovitz et al., Aug. 9, 1994, “Externally Mounted Track Apparatus for a Wheel Chair”); U.S. Pat. No. 5,423,563 (Wild, Jun. 13, 1995, “Wheelchair Having Apparatus for Climbing Stairs”); U.S. Pat. No. 5,868,403 (Culp et al., Feb. 9, 1999, “Medical Transport Device”); U.S. Pat. No. 6,076,619 (Hammer, Jun. 20, 2000, “All Terrain Vehicle for Disabled Persons”); U.S. Pat. No. 6,336,642 (Carstens, Jan. 8, 2002, “Safety Device for Stair-Climbing Systems”); U.S. Pat. No. 6,341,784 (Carstens, Jan. 29, 2002, “Motor-Driven Stair Climbing Device”); U.S. Pat. No. 6,805,209 (Hedeen, Oct. 19, 2004, “Wheelchair Motorizing Apparatus”); U.S. Pat. No. 6,857,490 (Quigg, Feb. 22, 2005, “Stair-Climbing Wheelchair”); U.S. Pat. No. 7,316,405 (Kritman et al., Jan. 8, 2008, “Stair-Climbing Apparatus”); and U.S. Pat. No. 7,384,046 (LeMasne De Chermont, Jun. 10, 2008, “Powered Wheeled Vehicle Capable of Travelling on Level Ground over Uneven Surfaces and on Stairs”); and U.S. patent applications 20030116927 (Quigg, Jun. 26, 2003, “Stair-Climbing Wheelchair”); 20030183428 (Hedeen, Oct. 2, 2003, “Wheelchair Motorizing Apparatus”); 20090230638 (Reed et al., Sep. 17, 2009, “Stair Chair”); and 20110031045 (Underwood, Feb. 10, 2009, “Tracked Mobility Device”).
9. Devices with Walking Legs
The ninth category (#9) of relevant prior art includes devices with legs for walking. This category includes: (#9a) devices with walking legs and no wheels; (#9b) devices with both walking legs and wheels; and (#9c) hybrid leg/wheel devices that have legs and no wheels, but wherein the legs interact together to function like one or more virtual circular wheels. I will now discuss the limitations of devices in these sub-categories in detail.
Future devices in sub-category #9a may prove to be the ultimate substitute for natural human bipedal movement. After all, humans normally travel by walking and most human-made environments are designed for walking. Artificial walking devices may someday provide the best means of traveling in human-made environments. However, walking technology, particularly bipedal walking technology, has not yet reached this level of performance. Most devices in this category have at least four legs. The resulting devices often look like giant robotic insects—not very appealing to most people. Also, devices in sub-category #9a do not provide a circular wheel for rapid, smooth transportation over flat, hard surfaces. Further, such devices tend to have a larger footprint and turning radius than wheeled devices. This can cause problems in constrained indoor environments. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations.
Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #9a—devices with walking legs and no wheels: U.S. Pat. No. 6,364,040 (Klann, Apr. 2, 2002, “Walking Device”); U.S. Pat. No. 6,478,314 (Klann, Nov. 12, 2002, “Walking Device”); U.S. Pat. No. 6,805,677 (Simmons, Oct. 19, 2004, “Wheel-Less Walking Support and Rehabilitation Device”); and U.S. Pat. No. 7,918,808 (Simmons, Apr. 5, 2011, “Assistive Clothing”); and U.S. patent applications 20030120183 (Simmons, Jun. 26, 2003, “Assistive Clothing”); and 20030191507 (Simmons, Oct. 9, 2003, “Wheel-Less Walking Support and Rehabilitation Device”).
Devices in sub-category #9b can be cumbersome because it can be difficult to combine legs and wheels in a single device. Also, devices in sub-category #9b do not offer the simplicity of a large circular wheel for rapid, smooth transportation over flat, hard surfaces. Further, devices in sub-category #9b cannot respond quickly to surface changes because of the time lag required to transition for legs to wheels, or vice versa. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations. Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #9b—devices with both legs and wheels: U.S. Pat. No. 4,265,326 (Lauber, May 5, 1981, “Rolling and Stepping Vehicle”); U.S. Pat. No. 5,513,716 (Kumar, May 7, 1996, “Adaptive Mobility System”); U.S. Pat. No. 6,328,120 (Haussler et al., Dec. 11, 2001, “Stair Climbing Vehicle”); U.S. Pat. No. 6,484,829 (Cox, Nov. 26, 2002, “Battery Powered Stair-Climbing Wheelchair”); U.S. Pat. No. 6,554,086 (Goertzen et al., Apr. 29, 2003, “Obstacle Traversing Wheelchair”); U.S. Pat. No. 6,923,280 (Goertzen et al., Aug. 2, 2005, “Obstacle Traversing Wheelchair”); U.S. Pat. No. 6,935,448 (Goertzen et al., Aug. 30, 2005, “Obstacle Traversing Wheelchair”); and U.S. Pat. No. 7,950,673 (Reed et al., May 31, 2011, “Stair Chair”); and U.S. patent application 20100013172 (Goertzen et al., Jan. 21, 2010, “Obstacle Traversing Wheelchair”).
Devices in sub-category #9c are novel and innovative, but they also have limitations. For example, devices in sub-category #9c do not offer the simplicity of a large circular wheel for rapid, smooth transportation over flat, hard surfaces. Also, sub-category #9c devices in the prior art do not appear to provide stair-climbing ability. Sub-category #9c devices also require complex (variable speed) and coordinated movement of arcuate legs in order to create a virtual circular wheel. While such complex movement may be possible on flat, hard surfaces, it may be challenging to operationalize when climbing obstacles or traversing staircases. The invention which I will disclose herein offers advantages over prior art in this sub-category because it does not have these limitations. Although categorization of prior art can be imprecise, the following seem to be examples of prior art that can be best classified into sub-category #9c—“hybrid leg/wheel devices that have legs and no wheels, but wherein the legs interact to function like one or more wheels: U.S. Pat. No. 7,017,687 (Jacobsen et al., Mar. 28, 2006, “Reconfigurable Articulated Leg and Wheel”); U.S. Pat. No. 7,543,663 (Setrakian et al., Jun. 9, 2009, “Bimodal Conveyance Mechanism”); U.S. Pat. No. 7,588,105 (Hillis et al., Sep. 15, 2009, “Virtual-Wheeled Vehicle”); U.S. Pat. No. 7,753,145 (Hillis et al., Jul. 13, 2010, “Virtual-Wheeled Vehicle”); and U.S. Pat. No. 7,836,983 (Setrakian et al., Nov. 23, 2010, “Bimodal Conveyance Mechanism”); and U.S. patent applications 20060076167 (Setrakian et al., Apr. 13, 2006, “Bimodal Conveyance Mechanism”); 20070227786 (Hillis et al., Oct. 4, 2007, “Virtual-Wheeled Vehicle”); 20080262661 (Setrakian et al., Oct. 23, 2008, “Bimodal Conveyance Mechanism”); 20090038863 (Hillis et al., Feb. 12, 2009, “Virtual-Wheeled Vehicle”); and 20100090426 (Setrakian et al., Apr. 15, 2010, “Bimodal Conveyance Mechanism”).
There are also devices in the prior art that seem to be generally relevant to the field of this invention, but which I was not able to classify into one of the above categories. This unclassified prior art includes the following: U.S. Pat. No. 4,355,451 (Thomas, Oct. 26, 1982, “Retractable Device and Method for Providing Traction”); U.S. Pat. No. 4,643,251 (Ziccardi et al., Feb. 17, 1987, “Traction Devices for Automotive Wheels”); U.S. Pat. No. 4,823,900 (Farnam, Apr. 25, 1989, “Four-Wheel Drive Wheel-Chair with Compound Wheels”); U.S. Pat. No. 4,913,685 (Lukatsch, Apr. 3, 1990, “Wheel with Variable Diameter”); U.S. Pat. No. 4,926,952 (Farnam, May 22, 1990, “Four-Wheel Drive Wheelchair with Compound Wheels”); U.S. Pat. No. 5,323,867 (Griffin et al., Jun. 28, 1994, “Robot Transport Platform with Multi-Directional Wheels”); U.S. Pat. No. 5,413,367 (Ochiai, May 9, 1995, “Movable Chair”); U.S. Pat. No. 5,507,513 (Peters et al., Apr. 16, 1996, “Multi-Terrain Wheelchair”); U.S. Pat. No. 5,690,375 (Schneider, Nov. 25, 1997, “Ezekiel's Wheel”); U.S. Pat. No. 5,842,532 (Fox et al., Dec. 1, 1998, “Personal Transport Vehicle and Method of Improving the Maneuverability of a Vehicle”); U.S. Pat. No. 5,983,452 (McGovern, Nov. 16, 1999, “Wheel Skid”); U.S. Pat. No. 6,003,624 (Jorgensen et al., Dec. 21, 1999, “Stabilizing Wheeled Passenger Carrier Capable of Traversing Stairs”); U.S. Pat. No. 6,073,958 (Gagnon, Jun. 13, 2000, “All Terrain Wheelchair”); U.S. Pat. No. 6,241,321 (Gagnon, Jun. 5, 2001, “All Terrain Wheel for a Wheelchair”); U.S. Pat. No. 6,276,703 (Caldwell, Aug. 21, 2001, “Land Rower”); U.S. Pat. No. 6,279,631 (Tuggle, Aug. 28, 2001, “Low Pressure Tire”); U.S. Pat. No. 6,367,817 (Kamen et al., Apr. 9, 2002, “Personal Mobility Vehicles and Methods”); U.S. Pat. No. 6,419,036 (Miglia, Jul. 16, 2002, “Vehicle for Wheel Chairs”); U.S. Pat. No. 6,538,411 (Field et al., Mar. 25, 2003, “Deceleration Control of a Personal Transporter”); U.S. Pat. No. 6,547,340 (Harris, Apr. 15, 2003, “Low Vibration Omni-Directional Wheel”); and U.S. Pat. No. 6,557,879 (Caldwell, May 6, 2003, “Land Rower”).
Uncategorized relevant prior art also includes U.S. Pat. No. 6,571,892 (Kamen et al., Jun. 3, 2003, “Control System and Method”); U.S. Pat. No. 6,581,714 (Kamen et al., Jun. 24, 2003, “Steering Control of a Personal Transporter”); U.S. Pat. No. 6,651,766 (Kamen et al., Nov. 25, 2003, “Personal Mobility Vehicles and Methods”); U.S. Pat. No. 6,715,780 (Schaeffer et al., Apr. 6, 2004, “Wheelchair”); U.S. Pat. No. 6,796,396 (Kamen et al., Sep. 28, 2004, “Personal Transporter”); U.S. Pat. No. 6,796,618 (Harris, Sep. 28, 2004, “Method for Designing Low Vibration Omni-Directional Wheels”); U.S. Pat. No. 6,815,919 (Field et al., Nov. 9, 2004, “Accelerated Startup for a Balancing Personal Vehicle”); U.S. Pat. No. 7,004,271 (Kamen et al., Feb. 28, 2006, “Dynamic Balancing Vehicle with a Seat”); U.S. Pat. No. 7,231,948 (Forney, Jun. 19, 2007, “Non-Pneumatic Tire”); U.S. Pat. No. 7,246,671 (Goren et al., Jul. 24, 2007, “Stair-Climbing Human Transporter”); U.S. Pat. No. 7,275,607 (Kamen et al., Oct. 2, 2007, “Control of a Personal Transporter Based on User Position”); U.S. Pat. No. 7,370,713 (Kamen, May 13, 2008, “Personal Mobility Vehicles and Methods”); U.S. Pat. No. 7,472,767 (Molnar, Jan. 6, 2009, “Wheelchair Suspension”); U.S. Pat. No. 7,562,728 (Voigt, Jul. 21, 2009, “Powered Wheelchair”); U.S. Pat. No. 7,648,156 (Johanson, Jan. 19, 2010, “Dual Mode Wheelchair”); U.S. Pat. No. 7,669,679 (Rastegar et al., Mar. 2, 2010, “Wheel Assembly for Decelerating and/or Controlling a Vehicle”); U.S. Pat. No. 7,690,447 (Kamen et al., Apr. 6, 2010, “Dynamic Balancing Vehicle with a Seat”); U.S. Pat. No. 7,690,452 (Kamen et al., Apr. 6, 2010, “Vehicle Control by Pitch Modulation”); U.S. Pat. No. 7,757,794 (Heinzmann et al., Jul. 20, 2010, “Vehicle Control by Pitch Modulation”); U.S. Pat. No. 7,761,954 (Ziegler et al., Jul. 27, 2010, “Autonomous Surface Cleaning Robot for Wet and Dry Cleaning”); U.S. Pat. No. 7,900,725 (Heinzmann et al., Mar. 8, 2011, “Vehicle Control by Pitch Modulation”); U.S. Pat. No. 7,900,945 (Rackley, Mar. 8, 2011, “All-Terrain Wheelchair”); U.S. Pat. No. 7,982,423 (Skaff, Jul. 19, 2011, “Statically Stable Biped Robotic Mechanism and Method of Actuating”); U.S. Pat. No. 8,002,294 (Brandeau, Aug. 23, 2011, “Vehicle Wheel Assembly with a Mechanism Compensating for a Varying Wheel Radius”); and U.S. Pat. No. 8,014,923 (Ishii et al., Sep. 6, 2011, “Travel Device”). Uncategorized relevant prior art also includes U.S. patent applications: 20060144494 (Tuggle, Jul. 6, 2006, “Low Pressure Tire”); 20060260857 (Kakinuma et al., Nov. 23, 2006, “Coaxial Two-Wheel Vehicle”); 20080295595 (Tacklind et al., Dec. 4, 2008, “Dynamically Balanced In-Line Wheel Vehicle”); 20090044990 (Lexen, Feb. 19, 2009, “Screw Driven Mobile Base”); 20090166996 (Spindle, Jul. 2, 2009, “Wheelchairs and Wheeled Vehicles Devices”); 20100102529 (Lindenkamp et al., Apr. 29, 2010, “Wheelchair with Suspension Arms for Wheels”); 20110050883 (Ghose et al., Mar. 3, 2011, “Machine Vision Based Obstacle Avoidance System”); 20110083915 (Nelson et al., Apr. 14, 2011,“Adjustable Mid-Wheel Power Wheelchair Drive System”); 20110175320 (Johnson et al., Jul. 21, 2011, “Stabilized Mobile Unit or Wheelchair”); and 20110204592 (Johansen et al., Aug. 25, 2011, “Mobility and Accessibility Device and Lift”).
This present invention is a motorized personal mobility device with shape-changing wheels for transporting a person over different surfaces and obstacles. This invention comprises novel technology that can be used to create next-generation motorized wheelchairs that can enable people who cannot walk independently to travel over ice and snow, to go “off-road” in rustic areas, and to travel up (and down) staircases by themselves. This invention includes: (1) a support structure that supports the person who is being transported; (2) a motor that moves the support structure by rotating at least one surface-contacting wheel, wherein the device travels on this surface; and (3) at least one shape-changing wheel that changes shape to travel more effectively on different surfaces and obstacles.
The shape of the shape-changing wheel is changed by the motorized rotation of at least two rotating members that are part of the shape-changing wheel. This rotation can be independent of the rotation of the wheel as a whole. Rotation of these rotating members into a first configuration causes the ground (or other travel surface) contacting perimeter of the wheel to be a first shape that is substantively circular. Rotation of these rotating members into a second configuration causes the ground (or other travel surface) contacting perimeter of the wheel to be a second shape that is non-circular.
More effective travel is achieved by one or more means selected from the group consisting of: more grasping, hooking, or other engagement of a substantially level, but slippery, surface in order to provide better traction on that surface; more reaching, stepping, or climbing over an obstacle on an otherwise substantially level surface; more grasping, hooking, or other engagement of a higher surface in order to pull the device upwards onto that higher surface, such as more grasping, hooking, or other engagement of successive stair treads to pull the device up a flight of stairs; more grasping, hooking, or other engagement of a lower surface to controllably lower the device downwards onto that lower surface, such as more grasping, hooking, or other engagement of successive stair treads to controllably lower the device down a flight of stairs; and differential changes in the shapes of two or more shape-changing wheels in order to help prevent the device from tipping over when traveling on a laterally-inclined surface, such as an increase in the diameter of perimeter of the downhill wheel of a pair of shape-changing wheels when traveling on a laterally-inclined surface.
This present invention has several potential advantages over the nine categories of personal mobility devices in the prior art that we just reviewed. This present invention has advantages over devices with wheels with extendable/retractable spikes/spokes because it provides: continuous frictional transition from circular to non-circular shape; and a greater area of the wheel perimeter in contact with the travel surface. This present invention has advantages over devices with wheels with differentially inflatable/deformable perimeter segments because it enables: a wide range of angular perimeter shapes for hooking, grasping, and climbing obstacles; and rapid shape-changing capability for responding to unexpected changes in travel surfaces and obstacles. This present invention has advantages over devices with wheels with differentially-inflatable parallel adjacent tires because: it does not require multiple parallel wheels and a wide turning radius which are unacceptable for many applications; it offers a wide range of angular perimeter shapes for hooking, grasping, and climbing obstacles; and it provides rapid shape-changing capability for responding to unexpected changes in travel surfaces and obstacles.
This present invention has advantages over devices with wheels with foldable/bendable perimeter segments because: it avoids material and structural weakening due to repeated bending or folding; it has an explicit and adjustable mechanism for restoring the perimeter of the shape-changing wheel to circular shape. This present invention has advantages over devices with wheels with differentially-expandable concentric rings because: it offers a wide range of angular perimeter shapes for hooking, grasping, and climbing obstacles; and it provides rapid shape-changing capability for responding to unexpected changes in travel surfaces and obstacles. This present invention has advantages over devices with compound wheels or multiple interacting circular wheels because: it offers a wide range of angular perimeter shapes for hooking, grasping, and climbing obstacles; and it offers the simplicity, speed, and smooth ride of a single large wheel for traveling on flat, hard surfaces.
This present invention has advantages over devices with multiple interacting non-circular wheels because: it offers the simplicity, speed, and smooth ride of a single large wheel for traveling on flat, hard surfaces; and it does not require multiple serial or parallel wheels and a wide turning radius, which are unacceptable for many applications. This present invention has advantages over devices with endless-loop tracks because: it offers a wide range of angular perimeter shapes for hooking, grasping, and climbing obstacles; it offers the simplicity, speed, and smooth ride of a single large wheel for traveling on flat, hard surfaces; and it avoids the weight of multiple inner wheels and endless-loop tracks. This present invention has advantages over devices with walking legs because it offers; the simplicity, speed, and smooth ride of a single large wheel for traveling on flat, hard surfaces; a relatively small footprint and turning radius; and good frictional engagement on ice, snow, or other slippery surfaces.
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In various examples, more effective travel on different surfaces and obstacles can be achieved by one or more means selected from the group consisting of: more grasping, hooking, or other engagement of a substantially level, but slippery, surface in order to provide better traction on that surface; more reaching, stepping, or climbing over an obstacle on an otherwise substantially level surface; more grasping, hooking, or other engagement of a higher surface in order to pull the device upwards onto that higher surface, such as more grasping, hooking, or other engagement of successive stair treads to pull the device up a flight of stairs; more grasping, hooking, or other engagement of a lower surface to controllably lower the device downwards onto that lower surface, such as more grasping, hooking, or other engagement of successive stair treads to controllably lower the device down a flight of stairs; and differential changes in the shapes of two or more shape-changing wheels in order to help prevent the device from tipping over when traveling on a laterally-inclined surface, such as an increase in the diameter of perimeter of the downhill wheel of a pair of shape-changing wheels on the same axel when traveling on a laterally-inclined surface.
In an example, rotation of the rotating members into a first configuration can cause the ground (or other travel surface) contacting perimeter of the wheel to be a first shape that is circular, rotation of these rotating members into a second configuration can cause the ground (or other travel surface) contacting perimeter of the wheel to be a second shape that is non- circular, portions of these rotating members form some or all of the ground (or other travel surface) contacting perimeter of the shape-changing wheel in both the first configuration and the second configuration, and these rotating members rotate around one or more axes that are different than the axis around which the wheel as a whole rotates.
In an example, motorized rotation of the rotating members shown in
In another example, motorized rotation of the rotating members shown in
We will now discuss some of the advantages of a personal mobility device that includes one or more shape-changing wheels, such as the wheel shown in
There are advantages of the present mobility device over “extendable spike or spoke” mobility devices in the prior art. “Extendable spike or spoke” devices have one or more wheels with spikes (or spokes) that can be changed from a first configuration in which the spikes are recessed below the main wheel perimeter to a second configuration in which the spikes protrude out from holes in the main wheel perimeter. One problem with such devices is that when the spikes (or spokes) extend out from the main wheel perimeter, there is a non-continuous transition from frictional engagement of the ground with the main wheel perimeter to frictional engagement with the, spikes (or spokes). This non-continuous transition can cause lose of frictional continuity and loss of device control. The present invention can avoid this problem by providing a smooth and continuous frictional transition. As shown in
Another problem with “extendable spike or spoke” devices is that the total area of ground contact with extendable spikes (or spokes) is limited because the spikes (or spokes) must be able to be radially retracted into holes in the main wheel perimeter without jamming together. This is a major problem when the spike or spokes radially intersect in a retracted position. Also, the holes in the main perimeter through which the spikes (or spokes) extend cannot be too large or the main perimeter becomes structurally unstable. The present invention avoids these problems entirely.
There are variations on “extendable spike of spoke” devices in the prior art in which there is no main wheel perimeter, just a radial array of extendable/retractable spokes. One problem with this variation is that the person being transported is subjected to a bumpy, jarring ride on most surfaces. A second problem is the above-mentioned limitation on the total area of contact between the ground and the wheel. The only contact with the ground is the tips of the spikes or spokes. This is not good frictional engagement for acceleration or a quick stop. The present invention avoids both of these problems.
There are also advantages of the present mobility device over “tank chair” mobility devices in the prior art. “Tank chair” devices have endless-loop tracks around multiple inner-wheels, in a manner reminiscent of the endless-loop tracks used in military tanks. In some examples, these endless-loop tracks are the only method of ground contact for the device. In other examples, such tracks are used in combination with one or more wheels, in a manner reminiscent of “half-track” vehicles in the military.
A first problem with “tank chair” devices is that endless-loop tracks around multiple inner wheels tend to be heavy. Heavy devices consume more energy, deplete battery life, are dangerous to the person if they tip over, and are difficult to move in the event of motor failure or battery failure.
A second problem with “tank chair” devices is that it is difficult to operationalize tracks with projections that are sufficiently long and stiff and angular to provide safe and secure engagement with step treads for climbing steps. Track projections on such devices tend to be short and/or flexible. A device with short and/or flexible projections can be insufficient to safely grasp stairs. If the heavy device slips, it can topple down the stairs and crush the person being transported.
A third problem with “tank chair” devices is that they do not provide a circular wheel for smooth, rapid travel over a flat, hard surface.
A fourth problem with “tank chair” devices is that they are difficult to maneuver in sharp turns.
A fifth problem with “tank chair” devices is their military appearance. Some people may welcome the attention that comes with riding around in a device that looks like a military tank, but other people would not welcome such attention and would prefer a more conventional-looking device. It might be fun to ride a “tank chair” outdoors along muddy trails, but such a big device would be awkward an indoor office or mall environment. The present invention overcomes all of these problems. It offers the surface-engaging ability of a tank for uneven, slippery outdoor surfaces (
There are variations on “tank chair” devices in the prior art wherein the device has both an endless-loop track and a set of wheels. Sometimes these devices offer a mechanism for raising or lowering the track vs. wheels into contact with the ground. One problem with such devices is the weight and bulk required to have both wheels and tracks. A second problem is the frictional discontinuity in the transition from one to the other. A third problem is the limitation on the speed with which the device can transition from track to wheels in response to unexpected changes in travel surfaces or obstacles. A fourth problem is the above-mentioned limitation of tracks to safely engage stairs. The present invention overcomes all of these problems.
There are also hybrid “extendable spoke track” devices in the prior art. These hybrid “extendable spoke track” devices combine the extendable spikes or spokes of “extendable spike or spoke” devices with the endless-loop tracks of “tank chairs.” These “extendable spoke track” devices generally have an endless-loop track that is supported by multiple inner wheels which are, in turn, mounted on radially extendable or retractable spokes. When the spokes are differentially extended or retracted, the shape of the endless-loop track changes.
A first problem with “extendable spoke track” devices is the difficulty of creating an endless-loop track that can vary in length without mechanical failures and breakage. If one makes an endless-loop track that can stretch, then it can slip on the gear mechanisms that drive it and can suffer material fatigue and breakage. If one makes an endless-loop track that cannot stretch, then one needs a mechanism for storing slack and maintaining tension in smaller-perimeter configurations. Such storage mechanisms can be complex and, if they involve a combination of convex and concave loops, can easily be clogged by debris on the track. The present invention avoids these problems.
A second problem with “extendable spoke track” devices is the general limitation with tracks that was discussed above, especially as a mechanism for climbing or descending stairs. It is hard to have projections on tracks that are sufficiently long or rigid to engage stair treads. Even if the endless-loop track is supported by spokes that can be differentially extended or retracted, there is an inherent roundness in endless-loop tracks. This roundness comes from the constraints on link bending in such tracks. Due to the constraints on link bending in tracks, there are limits on the creation of acute-angle projections (such as claws, hooks, teeth, or protruding arms) that would be useful for firmly grasping surfaces such as stair treads. The present invention overcomes both of these problems. The present invention enables a variety of claws, hooks, teeth, and protruding arms to firmly grasp stair treads and prevent the device from sliding down a flight of stairs.
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In an example, motorized rotation of the rotating members can be manually activated to travel more effectively on different surfaces and obstacles. For example, the person being transported by the device may see the change from travel surface 304 to travel surface 401 and then activate the shape-changing wheels. The person may manually activate rotation of these members to change the shape of the rear wheels for more effective travel over travel surface 401. In another example, motorized rotation of the rotating members can be automatically activated. For example, a visual sensor may detect the change from flat, hard travel surface 304 to uneven, slippery travel surface 401 and automatically change the shape of the rear wheels. In other examples, accelerometers or inclinometers or infrared emission or acoustic emission may detect the change from travel surface 304 to 401. In other examples, the device may communicate with a digital building blueprint, digital map, or GPS system to automatically anticipate changes in travel surfaces (or obstacles) and change the shape-changing wheels in advance of actually encountering these surfaces (or obstacles).
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In an example, this differential increase in the diameter of the downhill wheel shown in
This patent application claims the priority benefits of: U.S. patent application Ser. No. 12/589,407 entitled “Reinventing the Wheel” filed on Oct. 24, 2009 by Robert A. Connor of Medibotics LLC, Minnesota.
