Linkage energy return shoe
The key feature of the “linkage energy return shoe” is a compressible sole comprising a sole linkage which constrains the upper shoe plate to not tilt, in one embodiment, and to follow a controlled compression path, in general. A consequence of the anti-tilt feature inherent in the sole linkage is that a spring located anywhere in the sole resists sole compression at both the toe section and the heel section. Thus, one or two springs or stops suffice, and the modular design makes it a simple matter to change springs to tune the bow shoe to an individual's weight and gait and to change shoe and ground plates for different size feet. The spring system can easily give a constant force curve, a linear force curve, or any force curve in between—thereby permitting faster running for a given maximum force and thereby reducing impact injuries.
This application is a continuation-in-part of the following: (1) co-pending U.S. application Ser. No. 10/610,629 for a “Full Energy Return Shoe” filed on Jul. 2, 2003, (2) U.S. provisional application Ser. No. 17513 USPTO 60/505,431 for a “Guided Bow Shoe” filed on Sep. 25, 2003, and (3) U.S. provisional application Ser. No. 19587 USPTO 60/491970 for a “Full Energy Return Shoe” filed on Aug. 4, 2003.
BACKGROUNDThis invention is a linkage energy return shoe. It comprises various embodiments of an “energy return linkage,” referred to herein as a “sole linkage,” attached to upper and lower sole plates along their full lengths. The sole linkage constrains relative motion of the upper and lower sole plates by limiting or eliminating relative tilting and by controlling or eliminating relative longitudinal motion. These constraints result in foot impact energy being stored in springs regardless of whether the force acts on the front or rear of the sole. That is, both toe and heel impact energy are used or returned during toe-off. These springs are coupled to links or vertices of the linkage and are designed to achieve an optimal ground reaction force curve of the shoe on the ground—varying from linear to constant force curves. Most of the volume of the sole linkage is free space which distinguishes it from conventional running shoes which have solid, foam-filled structure of conventional running shoes.
A first type of sole linkage is referred to herein as a “guided p-diamond linkage” in that its linkage comprises a diamond shaped part, as well as overlapping parallelogram parts. The second type of sole linkage is referred to herein as a “p-linkage” in that its sole constraint is due to a parallelogram linkage which constrains the top of the sole to be parallel to the bottom of the sole, as it compresses. The shoes based on these two types of linkages are referred to herein collectively as “linkage shoes,” and particularly as the “guided p-diamond shoe” and the “p-linkage shoe.” The springs of the linkage shoe act directly between elements of the sole linkage. Another embodiment of the invention is a suspended linkage shoe, in which the top of the sole linkage is suspended from a bow spring, and it is referred herein as the “bow shoe.”
The p-diamond shoe constitutes an improvement of U.S. Pat. No. 6,684,531 of Rennex issued on Feb. 3, 2004, which discloses a p-diamond linkage and which incorrectly claims that this p-diamond linkage constrains the deflection of the sole to only the vertical degree of freedom The improved p-diamond shoe herein adds a guide element to achieve the claimed constraint. The new linkage herein is referred to as the guided p-diamond linkage. Extensive prior art is discussed in this earlier patent of Rennex, but it is not considered to be relevant to the new or old matter herein. In addition to the above improvement in the earlier patent, the current invention expands the scope of the earlier invention to a related and more extensive family of linkages in which the links rotate in the “up/forward” plane. Also, this invention increases the scope of these linkages to include asymmetric linkages, e.g., where the toe sole is thinner than the heel sole—in which case the linkages fall into the general class of quadrilaterals, of which the parallelogram in a particular example.
SUMMARYThe key feature of the linkage shoe is a compressible sole comprising a sole linkage which constrains the upper shoe plate not to tilt as it moves vertically up and down with respect to the ground plate. An advantage is that a minimal number of springs and stops (even one spring) of any kind can be used (without need of a spring guide). These springs and stops can easily be modular and replaceable to fit the performance requirements of an individual for walking and running. A consequence of the anti-tilt feature inherent in the sole linkage is that a spring located anywhere in the sole resists sole compression at both the toe section and the heel section. Thus, one or two springs or stops suffice, and the modular design makes it a simple matter to change springs to tune the bow shoe to an individual's weight and gait and to change shoe and ground plates for different size feet. The spring system can easily give a constant force curve, a linear force curve, or any force curve in between—thereby permitting faster running for a given maximum force and thereby reducing impact injuries.
BRIEF DESCRIPTION OF THE DRAWINGS
Push-off frame 18 is one example of an optional push-off means, which achieves the following functions. (1) It always allows the runner to flex her metatarsal joint to lift her heel and push off of her toe at toe off. (2) It prevents the runner's toe from twisting out of the foot attachment means at the toe section by constraining the rear part of the runner's foot to lift vertically with respect to the rear part of upper frame 6. (3) It can be used as part of a mechanism to lift the rear part of upper frame 6 to contact the runner's heel during swing phase. Push-off frame 18 may extend around the runner's heel a variable distance above the bottom of the heel, or it may extend only part way back toward the heel. It may also be a plate located at the bottom of the runner's heel and mid-foot, which plate may be have holes or voids of variable size. Another example of a push-off means is a largely vertically-oriented sliding guide, not shown, which is attached to upper frame 6, and which has a sliding element attached to the heel of linkage shoe 2 via a sliding element, again not shown—but obvious to one of ordinary skill in the art. Yet another example of a push-off means would improve the stability of push-off frame 18 by adding a pair of hinged plates hingeably connecting the back of upper frame 6 with the back of push-off frame 18. Runner's foot 1 is attached to cover plate 21 by shoe straps 22. Cover plate 21 is fixedly attached to upper frame 6 to form an upper sole plate, and cover plate 21 is fixedly attached to lower frame 4 to form a lower sole plate. Optional push-off frame 18 is hingeably connected to upper frame 6 below or on the outsides of the location of the metatarsal joint of runner's foot—thereby allowing the runner to push off naturally at toe-off. Lower frame 4 may incorporate ground plate rocker 30 and ground plate curved toe 32 to optimize the energy return of linkage shoe 2 (by permitting greater forward tilt at toe-off).
Guided p-diamond linkage 9 comprises four diamond links 10, one top length link 23, one center length link 24, one bottom length link 25, as well as two end links 14—all of which are hingeably connected in the depicted configuration by link hinges 16. Top length link 23 and bottom length link 25 optionally extend beyond link hinges 16 on either end, but the functional parts for guided p-diamond linkage 9, those which cause the critical constraint of guided p-diamond linkage 9 to maintain upper frame 6 and lower frame 4 parallel, require only the sections between link hinges 16. Another motion constraint is for upper frame 6 to not move longitudinally forward or backward with respect to lower frame 4, during compression. This constraint is provided by mid-link front vertex guide 71, rigidly attached to center length link 24 and extending horizontally to the left in
In total, all these links form a 9-bar linkage (plus mid-link front vertex guide 71), which constrains upper frame 6 to move vertically (with no tilting) with respect to lower frame 4. In this embodiment, upper frame 6 comprises two top length links 23, cross beams 13 at the top, and cover plate 21 at the top. Likewise, lower frame 4 comprises two bottom length links 25, cross beams 13 at the bottom, and cover plate 21 at the bottom.
Stops 44 and tethers 59 can be located so as to limit the motion of any link with respect to any other link. That is, stops 44 and tethers 59 may be located anywhere along any links, in any orientation, and there may be any number of these used in a particular embodiment.
It is understood with regard to all embodiments of linkage energy return sole 12 that any type of spring deemed useful can be used, and these may act in compression or tension between vertices or locations along links. Also, the anti-tilting constraint allows that a minimal number of vertical springs, even one, can suffice, and it ensures that both the heel and toe impact energy are returned through the runner's toe during the latter part of toe-off. Notably, single or multiple springs and stops, of any shape or type and between any locations on the mechanism elements, can be used to achieve any desired travel or compression from very little to the entire thickness of the unweighted sole. This full thickness may be only an inch or it may be six inches or more. Other spring options include tapered serpentine springs and air springs. By tapering a bow spring in a particular manner, it is possible to get just the right “hard” force curve where hard means the curve increases faster than a linear spring. Please refer to the discussion
Accordingly, as guided bow linkage 365 is compressed, the bottom of bow link 361 pushes rolling bearing 353 along bow-link guide 362, thereby stretching pre-bent bow 51 and thereby storing impact energy. At the end of compression, pre-bent bow 51 contracts, forcing upper frame 6 to lift all parts of runner's foot 1, including the toe, during toe-off. In this configuration upper frame 6 moves back and down as guided bow linkage 365 compresses and as vertical p-links 503 rotate clockwise. The opposite motion occurs during expansion. The fact that upper frame 6 is constrained to be parallel to lower frame 4 by the parallelogram nature of the linkage ensures that all the energy stored in pre-bent bow 51 acts to expand the front section of guided bow linkage 365, even if all the weight of the runner is on his toe at this time. The equivalent structural components shown in
It should be understood that the particular configurations shown may be varied using various springs and locations of elements while still being covered by this embodiment of the invention, which is to combine a parallelogram-based sole linkage with a guided link to load a spring in sole compression. Other features, such as stops and tethers, and additional springs acting between the upper and lower plates can be included in the broad scope of this invention. Note that guided bow linkage 365 is a simplification of guided p-diamond linkage 9 in that guided bow linkage 365 is essentially the top half of guided p-diamond linkage 9. Notably, it reduces the number of links from nine to five while adding a guide.
In contrast to the embodiments of
Another application of the guided p-diamond invention is bow shoe 202 shown in
Cords 228 attach to a front and a rear side point on upper frame 6 at equal distances in front of and behind ankle-pivot support 226. Cords 228 extend up to be guided through the center of ankle-pivot housing 234 so as to minimize any torque exerted by cord 228 on bow guide 238 about ankle pivot 232. Cords 228, four in all—from the front and rear on both sides, extend further up to attach to upper bow hinge 244. Accordingly, when runner's foot 1 pushes down on upper frame 6 during foot-strike, bow 240 is loaded via cords 228. Since rear and front cords 228 are symmetrically positioned about ankle-pivot support 228 and since guided p-diamond sole 8 forces vertical compression, bow 240 is loaded by either or both heel and toe impact. This ensures that the full impact energy is returned through the runner's toe at toe-off. To keep bow 240 from flopping about, it is attached to shin strap 246 via shin slider 248 which is slidingly connected to the upper part of the telescoping bow guide 238.
There are several embodiments herein of an energy return linkage other than guided p-diamond linkage 9. These do not provide as full a constraint on the relative motion of the top and bottom sole plates as the guided p-diamond linkage, but they still have useful functionality for “full” energy return in walking or running. Most importantly, full energy return means that all heel and forefoot impact energy (neglecting friction losses) is returned for thrust, optimally in the latter part of toe-off. The signature feature of these embodiments is that they extend over the full or major length of the foot. Also, all of the features that apply to use of guided p-diamond linkage 9, such as push-off frame 18, apply to these other embodiments.
The next embodiment, shown in
In summary, this “linkage energy return sole 12” invention includes several energy return linkages, all of which extend the full length of the shoe and all of which constrain the upper and lower plates or frame of the sole to move in a constrained manner with respect to one another so that the runner's toe is lifted in toe-off by both stored heel impact and toe impact energy and so that this thrust does not occur prematurely—as is the case for prior art energy return shoes in which the heel spring expands prematurely and wastefully. Note that the orientation of the “vertical motion only” constrained linkages of this invention can be rotated ninety degrees about the vertical axis so that the vertical links open laterally rather than longitudinally, provided that the effective “width” of this lateral linkage be the full length of the shoe sole. It is to be further understood within the full scope of the invention that any combination of the linkages described herein can be used together in any orientation to realize the invention goal of full energy return. And, any of the features described in a particular embodiment of the invention can be used in other embodiments of the invention.
While several forms of the invention have been shown and described, other forms will now be apparent to those skilled in the art. Therefore, it will be understood that the embodiments shown in the drawings and described above are merely for illustrative purpose, and are not intended to limit the scope of the invention which is defined by the claims which follow as interpreted under the principles of patent law including the doctrine of equivalents.
Claims
1. In a shoe a linkage energy return shoe sole for walking, running, and jumping by a wearer comprising
- an upper sole plate,
- a lower sole plate,
- a combined energy return linkage comprising one or more energy return linkages, wherein each said energy return linkage comprises at least one 4-bar linkage comprising four links hingeably interconnected at link hinges, wherein each link rotates in the longitudinal front-to-back plane formed by a vertical line and by a line extending from the front to back of said linkage energy return shoe sole,
- a spring system to store and return energy of compression of said linkage energy return shoe sole, wherein said spring system comprises at least one spring, wherein each one spring may act between any two locations on said combined energy return linkage, wherein the range action of each one spring may be restricted by various types of stops, and
- a foot attachment means to attach said linkage energy return shoe sole to the foot of said wearer, wherein said foot may be that of a person, a foot prosthesis, or a robot.
2. The linkage energy return shoe sole of claim 1 wherein said combined energy return linkage comprises links of various lengths, wherein opposing said links may or may not be parallel, wherein said upper sole plate may or may not be parallel to said lower plate, wherein the thickness of the front of said linkage energy return shoe sole may less or more than the thickness of the back of said linkage energy return shoe sole.
3. The linkage energy return shoe sole of claim 1 wherein said upper sole plate comprises a push-off means which allows said wearer to flex his metatarsal joint and push off his toe during toe-off.
4. The linkage energy return shoe sole of claim 1 wherein said bottom sole plate comprises a curved bottom wherein said curved bottom which comprises a curled toe, wherein said bottom sole plate is rigid.
5. The linkage energy return shoe sole of claim 3 wherein said push-off means comprises a push-off frame hingeably connected to said upper sole plate by a toe hinge and extending rearward, and fixedly attached to the rear foot of said wearer, wherein both the heel of said wearer and said push-off frame are free to rotate about said toe hinge and away from the rear section of said upper sole plate.
6. The linkage energy return shoe sole of claim 3 wherein said push-off means comprises a particular location and shape of said curled toe, wherein said linkage energy return shoe sole rocks forward throughout toe-off about the rolling bearing formed by said curled toe.
7. The linkage energy return shoe sole of claim 1 wherein said combination linkage comprises one or more guided p-diamond linkages each of which comprises nine links further comprising
- four diamond links,
- two end links,
- a top length link,
- a center length link,
- a bottom length link, wherein said nine links are hingeably connected by link hinges, wherein said top length link is rigidly attached to said upper sole plate, and said bottom length link is rigidly attached to said lower sole plate, wherein the four said diamond links are hingeably interconnected by said link hinges to form a diamond shape, with two top links and two bottom links, wherein two interconnecting diamond links, one of which is a bottom link, are called outside diamond links because they face away from the center of said p-diamond and the other two diamond links are called inside diamond links, wherein a top link hinge connecting the top two said diamond links is hingeably connected to said top length link, wherein a bottom link hinge connecting the bottom two diamond links is hingeably connected to said bottom length link, wherein the two said outside diamond links are hingeably connected by a link hinge called the outside link hinge, and the two inside diamond links are hingeably connected by a said link hinge called the inside link hinge, wherein said top length link is also hingeably connected to one of said end links, and said bottom length is also hingeably connected to the other one of said end links, wherein said end links are hingeably interconnected by a link hinge called the end center link hinge, wherein said center length link is connected to said inside link hinge and said end center link hinge, wherein the overall configuration of said nine links of said p-diamond linkage (for the particular but not the required case when all diamond links and end links are the same length) is two parallelograms and a diamond which overlap one another and that is why the invention is referred to as a p-diamond, wherein the two said outside diamond links constrain said p-diamond to compress in such a manner that said top length link remains parallel to said bottom length link which means said p-diamond compresses without tilting, and
- a mid-link front vertex guide rigidly extending along and from said center length link to make a key constraint on said outside link hinge to move within and along said mid-link front vertex guide, along the continuation line extending along the length of said mid length link, wherein said upper sole plate is constrained to move exactly vertically (with no tilting) with respect to said lower sole plate for the case when all of said diamond links and said end link have the same lengths, wherein said upper sole plate is constrained to move in a prescribed trajectory with the designed vertical travel with controlled tilting with respect to said lower sole plate for the case when all of said diamond links and said end links do not have the same lengths which is the case when the thickness of the front of said linkage energy return shoe sole is less than the thickness of back of said linkage energy return shoe sole.
8. The linkage energy return shoe sole of claim 7 wherein said spring system comprises one or more horizontal springs acting said inside link and said center length link, wherein said one or more horizontal springs may be attached at any location along the length of said center length link, wherein said one or more horizontal springs may be one of many types such as helical springs, leaf springs, or curved bow springs.
9. The linkage energy return shoe sole of claim 8 wherein said horizontal spring has a force curve which allows the vertical force curve of said spring system to be approximately constant over the compression of said p-diamond.
10. The linkage energy return shoe sole of claim 7 wherein said upper sole plate comprises a half-height sole comprising half-height hangars which extend downward from the level of the top of said top links and the level of the top of the top one of said end links to a level of approximately one-half that height—to fixedly attach to a half-height foot plate, thereby reducing the effective height of said linkage energy return shoe sole by a half and improving lateral sole stability.
11. The linkage energy return shoe sole of claim 1 wherein said combination linkage is a p-linkage comprising four p-links which hingeably interconnect via said link hinges to form a parallelogram.
12. The linkage energy return shoe sole of claim 1 wherein said combination linkage is a 2p-linkage comprising seven 2p-links which form two parallelograms with a shared link.
13. The linkage energy return shoe sole of claim 11 wherein said a p-linkage comprises a stretched-p linkage comprising one or pairs of stretched links hingeably interconnected at a stretched link hinge and hingeably connected to a top and a bottom left-most of said link hinges on the front side or on the back side, or on both front and back sides, wherein a stretched spring between one of stretched hinge and another stretched hinge resists compression of said p-linkage, wherein a stretched spring acts between said stretched hinge and an opposing one of said link hinges for the case when only one said pair of stretched links is used.
14. The linkage energy return shoe sole of claim 11 wherein said p-linkage comprises a hanging-p linkage comprising one or more p-extension hinges on the ends of p-link extensions which rigidly extend from front and back said p-links outward and toward the height center (diagonally downward for an upper said p-link and diagonally upward for a lower said p-link), wherein a lengthwise said spring is hingeably connected between the front and back said p-extension hinges, wherein interference of lengthwise said spring with other elements of said hanging-p linkage is reduced during compression of said hanging-p linkage.
15. The linkage energy return shoe sole of claim 1 which further comprises a bow shoe for use by a wearer, wherein said spring system comprises
- a bow spring located above said upper sole plate and hingeably connected to said upper sole plate,
- a leg attachment means for attaching said bow spring to the leg of said wearer,
- a suspension system connecting the top of said bow spring to said lower sole plate, wherein the force of both the wearer's toe and heel cause said bow spring to be loaded throughout foot-strike, wherein heel impact energy is not returned prematurely at the beginning of to push-off, but rather is returned optimally during toe-off during the latter part of push-off.
16. The linkage energy return shoe sole of claim 12 wherein said suspension system comprises
- one or more ankle-pivot supports rigidly attached to said lower sole plate and extending around and above the level of the foot of said wearer,
- one or more ankle-pivot housings rigidly attached to said ankle-pivot support and housing an ankle pivot,
- one or more cords attached to said upper sole plate and passing around the foot of said wearer and through said ankle-pivot housings, and
- a cord guide to constrain said cords to the location of said ankle-pivot.
17. The linkage energy return shoe sole of claim 12 wherein said suspension system further comprises a shin-level bow spring assembly comprising
- a bow spring pivotly attached to said ankle-pivot housing,
- a bow guide pivotly attached to said ankle-pivot housing and to the top of said bow spring, wherein said bow guide changes length telescopically,
- a shin slider slidingly attached to the top of said bow guide, and
- a shin strap for attaching said shin slider to the shin of said wearer, wherein said cords extend to connect to the top of said bow spring, wherein the impact force of said wearer's foot on said shoe plate loads said bow spring via said cords.
18. A guided p-diamond shoe sole for walking, running, and jumping by a wearer comprising a guided p-diamond sole comprising
- an upper sole plate,
- a lower sole plate,
- one or more guided p-diamond linkages each of which comprises nine links further comprising
- four diamond links,
- two end links,
- a top length link,
- a center length link,
- a bottom length link, wherein said nine links are hingeably connected by link hinges, wherein said top length link is rigidly attached to said upper sole plate, and said bottom length link is rigidly attached to said lower sole plate, wherein the four said diamond links are hingeably interconnected by said link hinges to form a diamond shape, with two top links and two bottom links, wherein two interconnecting diamond links, one of which is a bottom link, are called outside diamond links because they face away from the center of said p-diamond and the other two diamond links are called inside diamond links, wherein a top link hinge connecting the top two said diamond links is hingeably connected to said top length link, wherein a bottom link hinge connecting the bottom two diamond links is hingeably connected to said bottom length link, wherein the two said outside diamond links are hingeably connected by a link hinge called the outside link hinge, and the two inside diamond links are hingeably connected by a said link hinge called the inside link hinge, wherein said top length link is also hingeably connected to one of said end links, and said bottom length is also hingeably connected to the other one of said end links, wherein said end links are hingeably interconnected by a link hinge called the end center link hinge, wherein said center length link is connected to said inside link hinge and said end center link hinge, wherein the overall configuration of said nine links of said p-diamond linkage (for the particular but not the required case when all diamond links and end links are the same length) is two parallelograms and a diamond which overlap one another and which is why the invention is referred to as a p-diamond, wherein the two said outside diamond links constrain said p-diamond to compress in such a manner that said top length link remains parallel to said bottom length link which means said p-diamond compresses without tilting, and
- a mid-link front vertex guide rigidly extending along and from said center length link to make a key constraint on said outside link hinge to move within and along said mid-link front vertex guide, along the continuation line extending along the length of and from said center length link, wherein said upper sole plate is constrained to move exactly vertically (with no tilting) with respect to said lower sole plate for the case when all of said diamond links and said end link have the same lengths, wherein said upper sole plate is constrained to move in a prescribed trajectory with the designed vertical travel with controlled tilting with respect to said lower sole plate for the case when all of said diamond links and said end links do not have the same lengths which is the case when the thickness of the front of said linkage energy return shoe sole is less than the thickness of back of said linkage energy return shoe sole,
- a spring system to store and return energy of compression of said guided p-diamond sole, wherein said spring system comprises at least one spring and wherein each one spring may act between any two locations on said guided p-diamond linkage and wherein the range action of each one spring may be restricted by various types of stops, and
- a foot attachment means to attach shoe sole to the foot of said wearer, wherein said foot may be that of a person, a foot prosthesis, or a robot.
Type: Application
Filed: Aug 4, 2004
Publication Date: Dec 1, 2005
Inventors: Brian Rennex (Chevy Chase, MD), Bartholomew Hogan (Rockville, MD)
Application Number: 10/910,643