Claims
- 1. An energy-efficient shoe wherein the sole of said shoe comprises:
- intermediate energy storage means for storing energy of heel impact upon a running surface;
- transmission means in the heel of said sole for transmitting said energy to said intermediate energy storage means; and
- thrust means in the front of said sole and coupled to said intermediate energy storage means for releasing said energy during thrust off of said running surface, whereby the center of mass of the wearer of said shoe is impelled upward from said running surface.
- 2. The energy-efficient shoe of claim 1, wherein said transmission means comprises:
- a rear force plate for receiving the force of said heel impact;
- force re-direction means for changing the direction of said heel impact force from substantially perpendicular to said rear force plate to substantially parallel with said rear force plate; and
- force transmission means for transmitting said direction-changed heel impact force from the rear of said sole to the front of said sole.
- 3. The energy-efficient shoe of claim 2, further comprising a housing to which said rear force plate is movably coupled and which prevents said rear force plate from tilting relative to the plane of said sole.
- 4. The energy-efficient shoe of claim 2, wherein said force re-direction means comprises:
- a pair of bent levers;
- two pairs of hinged links; and
- an axle embedded in said sole, wherein said bent levers are rotatably connected at the opposite ends of said axle and the end of each arm of each of said bent levers is rotatably connected to one of said hinged links.
- 5. The energy-efficient shoe of claim 2, wherein said force transmission means comprises a pair of drive shafts and a housing for said drive shafts and wherein said drive shafts are coupled at one end thereof to said first force re-direction means and coupled at the opposite end thereof to said second force re-direction means.
- 6. The energy-efficient shoe of claim 2, wherein said first force re-direction means comprises a pair of rack and pinion mechanisms, each of which comprises:
- a first rack aligned perpendicular to the plane of said rear force plate and coupled at one end to said rear force plate;
- a second rack aligned parallel to the plane of said rear force plate and coupled at one end to said force transmission means; and
- a pinion rotatably coupled to said first rack and the opposite end of said second rack.
- 7. The energy-efficient shoe of claim 1, wherein said thrust means comprises:
- a storage force plate;
- a thrust force plate;
- energy release means which allows said thrust force plate to push against said running surface during thrust; and
- recovery means which allows said storage force plate and said thrust force plate to return to their pre-impact positions after thrust of said shoe.
- 8. The energy-efficient shoe of claim 7, wherein said intermediate energy storage means comprises:
- means coupled to said transmission means for moving said storage force plate toward said thrust force plate in response to the energy received from said transmission means;
- energy storage means connected between said storage force plate and said thrust force plate; and
- ratchet means which allow said storage force plate and said thrust force plate to move only toward each other, thereby increasing the energy stored in said energy storage means.
- 9. The energy-efficient shoe of claim 8, wherein said energy storage means comprises a helical spring.
- 10. The energy-efficient shoe of claim 8, wherein said energy storage means comprises an elastomer.
- 11. The energy-efficient shoe of claim 8, wherein said energy storage means comprises a resilient plastic material.
- 12. The energy-efficient shoe of claim 1 wherein said thrust means comprises:
- a plurality of storage force plates;
- a thrust force plate;
- energy release means for allowing said thrust force plate to push against said running surface during thrust; and
- a plurality of recovery means, each of which is coupled to a different one of said storage force plates and allows said storage force plate to return to its rest position after thrust.
- 13. The energy-efficient shoe of claim 12, wherein said intermediate energy storage means comprises:
- a plurality of springs, each of which is connected at one end to a different one of said storage force plates and at the other end to said thrust force plate; and
- means for moving said storage force plates toward said thrust force plate in a timed sequence whereby only one storage force plate moves at a time and each succeeding storage force plate begins said movement after the preceding storage force plate reaches its closest distance to said thrust force plate.
- 14. The energy-efficient shoe of claim 13, wherein said moving means comprises a plurality of bent lever driving means each of which comprises:
- a bent lever;
- a first roller bearing rotatably mounted at the end of one arm of said bent lever and in contact with the top surface of said storage force plate; and
- a second roller bearing rotatably mounted at the end of the other arm of said bent lever and in contact with said transmission means, whereby said bent lever rotates in response to the energy transmitted by said transmission means and moves a different one of said storage force plates towards said thrust force plate.
- 15. The energy-efficient shoe of claim 13, wherein said moving means comprises:
- a plurality of bellows, each of which is connected at one end to a different one of said storage force plates;
- a control valve having a single input port, a plurality of output ports and means for routing hydraulic fluid from said input port to each of said output ports in a timed sequence; and
- a plurality of output tubes, each of which is coupled at one end to a different one of said output ports and at the other end to a different one of said bellows, whereby each of said bellows is hydraulically activated in said timed sequence.
- 16. The energy-efficient shoe of claim 1, wherein said thrust means comprises:
- a first storage force plate;
- a second storage force plate;
- a thrust force plate;
- energy release means for allowing said thrust force plate to push against said running surface during thrust; and
- recovery means for allowing said first storage force plate and said second storage force plate to return to their rest positions after thrust of said shoe.
- 17. The energy-efficient shoe of claim 16, wherein said intermediate energy storage means comprises:
- a first storage spring connected at one end to said first storage force plate and at the other end to said thrust force plate;
- a second storage spring connected at one end to said second storage force plate and at the other end to said thrust force plate; and
- means for moving said first storage force plate and said second storage force plate to achieve for a first specified period of time a linearly increasing force acting against said thrust force plate and to achieve for a second specified period of time a constant force acting against said thrust force plate.
- 18. The energy-efficient shoe of claim 1, wherein said transmission means comprises:
- a rear force plate for receiving said heel impact force;
- a first housing mounted over said rear force plate;
- a second housing mounted at the front of said shoe sole;
- a bellows connected at one end to said rear force plate and at the other end to said housing; and
- a tube connected at one end to said bellows and at the other end to said storage/thrust means, whereby said heel impact force moves said rear force plate upward, causing compression of said bellows and hydraulic transmission of said heel impact energy to said storage/thrust means.
- 19. The energy-efficient shoe of claim 18, wherein said bellows contains a plurality of hollow spheres, each of which has a diameter at least three times the diameter of said tube.
- 20. The energy-efficient shoe of claim 1, wherein said transmission means comprises:
- a rear force plate for receiving said heel impact force;
- a housing mounted over said rear force plate;
- a piston connected at one end to said rear force plate and at the other end to said housing; and
- a tube connecting the chamber of said first piston to said storage/thrust means, whereby said heel impact force moves said rear force plate upwards causing compression of said first piston and operation of said storage/thrust means.
- 21. The energy-efficient shoe of claim 1, wherein said transmission means comprises:
- a rear force plate for receiving said heel impact force;
- a housing mounted over said rear force plate;
- a drive shaft aligned parallel to said sole;
- a first bellows having its axis aligned perpendicular to the sole of said shoe and connected at one end to said rear force plate and at the other end to said housing;
- a second bellows having its axis aligned parallel to the sole of said shoe and connected at one end to said housing and at the other end to said drive shaft; and
- a tube connected between said first bellows and said second bellows, whereby said heel impact force compresses said first bellows, expands said second bellows and moves said drive shaft forward.
- 22. The energy-efficient shoe of claim 1, wherein said energy is transmitted by hydraulic fluid from said transmission means to said intermediate energy storage means and from said intermediate energy storage means to said thrust means.
- 23. The energy-efficient shoe of claim 22, wherein said transmission means comprises:
- an energy accumulator for storing hydraulically delivered energy;
- a first energy transfer means for transmitting hydraulic fluid from said transmission means to said energy accumulator;
- a second energy transfer means for transmitting said hydraulic fluid from said energy accumulator to said thrust means; and
- a third energy transfer means for transmitting said hydraulic fluid from said thrust means to said transmission means.
- 24. The energy-efficient shoe of claim 23, wherein said first energy transfer means comprises:
- a tube for transmitting hydraulic fluid from said transmission means to said energy accumulator; and
- a valve connected to said tube for permitting said hydraulic fluid to flow from said transmission means to said energy accumulator and for preventing said hydraulic fluid from flowing from said energy accumulator to said transmission means.
- 25. The energy-efficient shoe of claim 23, wherein said energy accumulator comprises:
- a first compartment for storing said hydraulic fluid; and
- a second compartment isolated from said first compartment for storing a compressible gas.
- 26. The energy-efficient shoe of claim 25, wherein said energy accumulator comprises:
- a housing;
- a compressible medium contained in said housing; and
- actuation means for hydraulically compressing said compressible medium.
- 27. The energy-efficient shoe of claim 25, wherein said compressible medium comprises a gas.
- 28. The energy-efficient shoe of claim 26, wherein said compressible medium comprises a mechanical spring.
- 29. The energy-efficient shoe of claim 26, wherein said compressible medium comprises an elastomer.
- 30. The energy-efficient shoe of claim 23, wherein said second fluid transfer means comprises:
- a tube connected between said energy accumulator and said thrust means;
- a valve connected to said tube for permitting hydraulic fluid to flow from said energy accumulator to said thrust means through said tube; and
- control means for opening said valve during impact of the toe portion of said sole on said running surface and for closing said valve after said hydraulic fluid is transmitted from said energy accumulator to said thrust means.
- 31. The energy-efficient shoe of claim 23, wherein said third fluid transfer means comprises:
- a tube connected between said thrust means and said transmission means;
- a valve connected to said tube for permitting hydraulic fluid to flow from said thrust to said transmission means; and
- control means for opening said valve immediately following thrust off of said running surface by said shoe and for closing said valve at other times, whereby said hydraulic fluid is transmitted from said thrust means to said transmission means when said valve is opened.
- 32. The energy-efficient shoe of claim 22, wherein said means comprises;
- a front plate attached to the front portion of said sole; and
- an hydraulic reservoir fixedly attached at one end to said front plate and located in a cavity in said front portion of said sole.
- 33. The energy-efficient shoe of claim 32, wherein said impeller means further comprises a resilient front portion of said sole for storing toe impact energy.
- 34. The energy-efficient running shoe of claim 22, wherein said transmission means comprises:
- a rear hydraulic reservoir in the heel portion of said sole containing hydraulic fluid prior to impact of said heel upon said running surface;
- an upper rear plate in the top of said sole fixedly attached to one end of said rear hydraulic reservoir; and
- a lower rear plate in the bottom of said sole, fixedly attached to the opposite end of said rear hydraulic reservoir, wherein during impact of said heel upon said running surface said upper rear plate and said lower rear plate compress said rear hydraulic reservoir, thereby transmitting said hydraulic fluid from said rear hydraulic reservoir to said intermediate energy storage means.
- 35. The energy-efficient shoe of claim 34, wherein said rear hydraulic reservoir comprises a bellows.
- 36. The energy-efficient shoe of claim 34, wherein said rear hydraulic reservoir comprises a conical disk spring.
- 37. The energy-efficient shoe of claim 34, wherein said hydraulic reservoir comprises a bladder.
- 38. The energy-efficient shoe of claim 34, wherein said rear hydraulic reservoir comprises a piston.
- 39. The energy-efficient shoe of claim 34, further comprising heel stabilizer means for preventing shear and torsional motion of said heel.
- 40. The energy-efficient shoe of claim 39, wherein said heel stabilizer means comprises a bellows surrounding said rear hydraulic reservoir.
- 41. The energy-efficient shoe of claim 39, wherein said heel stabilizer means comprises:
- a back frame rigidly attached to the bottom of said lower rear plate, oriented vertically with height approximately equal to the thickness of said sole and width extending across the back of said sole;
- a cross frame for strengthening said back frame;
- stabilizer cables for providing a sliding connection between said back frame and said upper rear plate; and
- stabilizer rollers for allowing said sliding connection to have low friction, wherein said upper rear plate is constrained to move up and down with respect to said lower rear plate during foot strike, without significant tilting or shearing.
- 42. An energy-efficient shoe wherein the sole of said shoe comprises:
- a plurality of intermediate energy storage means for storing energy of heel impact upon a running surface;
- a plurality of transmission means in the heel of said sole, each of which transmits energy of heel impact upon a running surface to a corresponding one of said intermediate energy storage means; and
- a plurality of thrust means positioned in the front of said sole, each of which is coupled to a corresponding one of said intermediate energy storage means and releases during thrust off of said running surface said energy accumulated by said one of said corresponding intermediate energy storage means, whereby the center of mass of the wearer of said shoe is impelled upward from said running surface.
- 43. The energy-efficient shoe of claim 42, wherein the sole of said shoe further comprises transmission means located in the mid-sole portion thereof for transmitting energy obtained from impact of said mid-sole portion on said running surface to locations forward of said mid-sole portion.
BACKGROUND OF THE INVENTION
This is a continuation-in-part of Application Ser. No. 065,595, now abandoned, filed 6-23-87. This invention relates to running shoes and in particular to energy-efficient running shoes.
The act of running involves vertical motion of a runner's center of gravity. The lifting of the runner's weight requires muscle work. When the runner's foot impacts the ground, the kinetic energy and the momentum associated with the vertical motion must be absorbed. Some of the vertical kinetic energy is stored in the resilient parts of the leg and foot, but most of it is lost to the ground and the leg. The lost energy must be replaced by muscle work. This invention is intended to minimize lost energy or, equivalently, to maximize the energy efficiency of running.
Scientific inquiry of running includes the study of the efficiency of running as a function of various parameters. Researchers have been attempting to apply their results to the optimization of running parameters to achieve greater energy efficiency and to reduce injuries. Dr. Thomas A. McMahon of Harvard University discussed how the resiliency of tracks can be tuned to improve performance and safety in his article "Mechanics of Locomotion," T. McMahon, 3 Int. J. of Robotics Research 4 (1984). One of his results is that running times improve by two or three percent and injuries are reduced by a factor of two when the effective spring constant of the track is approximately two times that of a runner's leg. Running shoes cannot improve energy efficiency equivalent to that achieved with tuned tracks, however, because impact is on the heel whereas take-off is from the toe.
Even if all of the impact energy is efficiently returned to the runner in toe thrust, the improvement in running times is expected to be only two or three percent. The reason is that the shoe acts in series with the runner's leg. Also, for effective running, the runner's knee must bend almost the same amount regardless of the spring in the shoes. Consequently, the runner's leg must work to support almost the same force for almost the same time, even though the shoe is providing some springboard action. The small benefit of a few percent results from the fact that the springboard action enables the runner to bound slightly higher, while bending the knee slightly less, for an equivalent amount of muscle work. Prior art running shoes capture roughly half of the impact energy (that due to front sole impact) and would be expected to improve running times by roughly one percent. My invention captures the other half and improves running times by yet another one percent.
Two concepts important in understanding the manner in which running shoes operate are compliance and resilience. Compliance refers to the property of the sole to give or compress upon foot impact; resilience refers to the property of the sole to return to its original shape. This can be made clearer by referring to a spring model with damping. The term damping includes all friction losses. A spring system may be very compliant by virtue of having considerable damping, but not energy efficient. Prior art running shoes have this drawback. The term resilience as used herein means that damping is minimized, so energy efficiency is maximized. In summary, compliance describes a system where impact energy is lost as well as conserved, whereas resilience refers to a system where energy loss is minimized.
An example of an invention that provides compliance in a shoe is described in U.S. Pat. No. 4,446,634. This shoe has liquid-filled bladders under the heel and sole, and controls the heel compliance with an adjustable valve in between. Since provision is made for energy storage and release, however, this shoe would not be energy efficient.
U.S. Pat. Nos. 4,237,625 and 4,358,902 disclose energy-efficient shoes. These have liquid-filled bladders below the heel and ball of the foot and resilient material below these bladders. However, there is no provision to transmit the energy of heel impact to the front of the foot, to store it, and to release it during thrust. The only energy that might be returned during thrust is that stored in the resilient material below the front of the foot, and this would be a small portion of the impact energy. Accordingly, this shoe would not be very energy-efficient.
U.S. Pat. No. 4,451,994 discloses a shoe having a resilient mid-sole. This shoe cannot capture the heel-impact energy, nor can it give back much of the "midsole-impact" energy during thrust. U.S. Pat. No. 4,030,213 discloses a shoe with springs throughout the sole. This shoe may be compliant, but it would not be energy efficient, since there is no provision for transferring heel impact energy to the front of the shoe.
Other references discovered by applicant during a prior art search are the following: U.S. Pat. Nos. 3,914,881; 4,217,705; 4,420,893; 4,546,555; 4,183,156; 4,486,964; 4,763,426; 4,635,384 and 4,342,158. Although compliant shoes are disclosed in these patents, none are energy-efficient.
Accordingly, one subject of the present invention is to provide a running shoe with improved performance that will make running more enjoyable and satisfying.
Another object of the present invention is to provide a running shoe that will reduce injuries.
A further object of the present invention is to provide a running shoe that will provide a high level of energy efficiency and adequate compliance on existing non-compliant surfaces, such as concrete.
A still further object of the present invention is to provide a shoe that will make walking less tiring and more comfortable by reducing the shock on the foot and other body parts.
Another still further object of the present invention is to provide a running shoe that has the ability to dramatically reduce impact shocks on the foot and body to compensate for weakened body parts, without a loss of running speed or energy efficiency.
Another object of the present invention is to provide a running shoe that corrects for pronation problems.
Yet another object of the present invention is to improve running times over prior art running shoes.
Other objects of the present invention will be apparent to those skilled in the art from the specification and drawings.
Briefly, in accordance with one embodiment of this invention, the foregoing objectives are achieved by providing a running shoe with a sole structure that transmits the force and energy of heel impact produced by vertical kinetic energy to the front of the shoe where it is stored. At the proper time this energy is released to contribute to the thrust off of the running surface at the front of the shoe.
The structure of this embodiment is comprised of two mechanisms. The first, referred to hereinafter as the "transmission mechanism," transmits the heel impact force to the front of the foot; the second, referred to hereinafter as the "storage/thrust mechanism," stores the energy associated with this force and then releases it during thrust. The transmission mechanism is mechanically coupled to the storage/thrust mechanism so that when the runner's heel impacts the running surface, the resulting impact energy is transmitted to the front of the foot where it is briefly stored and then released from the front of the foot during takeoff.
In another embodiment the foregoing objectives are achieved by providing means in the heel of the shoe which transmits the energy of heel impact produced by vertical kinetic energy, means for storing this energy and separate means in the front of the shoe for releasing this energy to contribute to thrust off of the running surface.
US Referenced Citations (18)
Foreign Referenced Citations (1)
| Number |
Date |
Country |
| 2183446 |
Nov 1986 |
GBX |
Non-Patent Literature Citations (3)
| Entry |
| "Groucho Running," J. Applied Physiology 23-26 (Jun. 1987), by T. McMahon and P. Greene. |
| "Running Shoes Waste Natural Energy of Feet," N.Y. Times, Sect. C, p. 2 (Jun. 2, 1987) by J. Gleick. |
| "Mechanics of Locomotion," 3Int. J. of Robotics Research 4 (1984), by T. A. McMahon. |
Continuation in Parts (1)
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Number |
Date |
Country |
| Parent |
65595 |
Jun 1987 |
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Patent Grant
4936030
