Abstract:
A system for harvesting footwear energy. The energy may be in a form of footwear movement which involves a compression and decompression of chambers situated in the footwear. There may be a back chamber in the heel area and a front chamber in the toe area of the footwear. The chambers may be filled with gas which moves in and out upon compression and decompression of the chambers at the heel and toe areas upon the ambulatory motion of a person wearing the footwear. The moving gas may go through a pneumatic rectifier that provides a unidirectional stream of gas to spin a micro-turbine which turns an electrical generator, or operate a pneumatic device.

Description:
This invention claims the benefit of U.S. Provisional Application No. 60/872,220, filed Dec. 1, 2006. U.S. Provisional Application No. 60/872,220, filed Dec. 1, 2006, is hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present invention pertains to energy converters, and particularly to a capture and conversion of bodily motion to a form of energy. 
     SUMMARY 
     The invention is a system for harvesting footwear energy, storing it, using it in an application, and/or converting it into another type of energy. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURE 
         FIG. 1  is a diagram of an energy generating mechanism implementation in footwear; 
         FIGS. 2   a  and  2   b  are diagrams of back-front chambers of the footwear for double action shown in conjunction with a pneumatic rectification circuit and an energy conversion device; and 
         FIG. 3  is a diagram of footwear in action with a cut-away illustration of the energy conversion device. 
     
    
    
     DESCRIPTION 
     With increased use of power-consuming portable electronics, the need for compact and lightweight power sources in replacement of batteries appears to be a pressing issue. Energy harvesting from walking, in particular via the force and compression in the footwear soles, has the potential to deliver one to five watts average power with negligible interference with a normal human gait. There appears to be a very significant amount of available “waste” power from normal human activity. However, converting watt-level mechanical body or foot power to usable electricity or other kind of power by a miniature device integratable into body wear such as footwear is approached here in a new way. Many similar existing devices appear cumbersome, inefficient and consequently impractical. 
     The present invention is a system which may be based on an approach of transmitting the sole-compression pneumatically, for instance, to a high-speed microturbine (or micro turbine), or other pneumatic-to-mechanical converter, which in turn can drive a rotary electromagnetic generator, another energy converter, provide electrical or pneumatic energy to a storage mechanism, and so forth. The pneumatic-to-mechanical converter and the electrical generator in combination may be regarded as a pneumatic-to-electrical converter. The sole or other body wear compression may be transmitted to various energy converters or translators such as a massager or pump (not shown). Sole-compression may be transmitted as a moving fluid in one direction via a pneumatic rectifier to drive a component. An example kind of shoes which may be adapted for the present system may be running or tennis shoes. The term “present” refers to the invention herein. “Fluid” may refer to a gas or liquid. 
     The component may be a microturbine for driving an electrical generator to provide power to activate a mechanism for use, or a device for electrical storage. The electrical or electronic mechanism may be a cell phone, a PDA (personal digital assistant), a portable computer, body safety or navigation lights, a GPS (global positioning system) device, a warmer for hands, feet, or other portions of the body, various kinds of instrumentation, and so on. In one implementation, a foot warmer may include electrical heating elements formed in socks or built into shoes. A device, such as a chargeable battery or high capacity capacitor, may be provided electrical power by the microturbine-generator for storage. Power may be provided by the generator to both a mechanism and storage. For example, batteries of personal electronic devices may be charged. A common situation may be where some people spend much time on a cell phone while walking around and then frequently have to discontinue their call because of a low battery in the cell phone. With the present system connected to the phone, one could talk indefinitely while walking around to one or more destinations, whether at work or on time off. Whether the phone is being used or not, the cell phone battery may get charged up while walking or running, thus obviating a need to find a source of power, such as an outlet, to plug the phone in for a recharge. 
     The component may instead be a massager or other similar pneumatically drivable mechanism associated with a person such as the wearer to provide massaging or other physical therapy. The pneumatically powered massager or other mechanism may be in contact with the wearer&#39;s body in an applicable place or manner, such as the wearer&#39;s feet. Such massaging or therapy, for example, may used to reduce foot and/or leg fatigue of the wearer while walking. The massager or like mechanism may consist of one or more pneumatically inflatable and deflatable bags or pouches proximate to the feet and/or legs of the wearer, and have a pneumatic valve device to alternate filling and releasing a gas, such as air, to and from the pouches. 
     A pneumatically drivable pump may be connected to the present system and be used for moving fluids for one application or another, such as a pneumatic tool, gas storage under pressure, and so forth. 
       FIG. 1  is a diagram of an example system  10  of the present invention with a shoe  11  having a sole  19  with compressible chambers  12  and  13 . Back chamber  12  at the heel of shoe  11  may have an output  14  and an input  15 . When back chamber  12  is compressed, a gas  18  may be expelled through output  14  from chamber  12 , particularly when a foot in the shoe  11  is putting weight on the heel of the shoe  11 . When weight on the heel is removed, then chamber  12  may decompress and return to its original shape and internal volume. At the same time, gas  18  may return to chamber  12  through the input  15 . Also at the same time, the foot in the shoe  11  may be shifting the weight from the heel to the toe and thus compressing chamber  13  and expelling gas  18  through an output  16 . When the weight on the toe is removed, the chamber  13  may decompress and return to its original shape and internal volume. At the same time, gas  18  may return to chamber  13  through the input  17 . Also at the same time, the foot in the shoe may be shifting the weight from the toe to the heel and again compressing chamber  12  thereby expelling gas  18  through output  14 . Such heel-toe or back-front double action may continue to repeat itself indefinitely while a person with the foot is proceeding with an ambulatory motion or some other physical activity. Gas  18  may permit system  10  to operate at various temperatures. 
       FIGS. 2   a  and  2   b  are diagrams of back-front chambers  12  and  13  for double action shown in conjunction with a pneumatic rectification circuit or rectifier  20  and an energy conversion device  25 . The double action may be referred to as front-back, heel-front, front, back, or the like. Chambers  12  and  13  may be embedded insole of shoe  11  and have elastomer walls which facilitate compressibility and decompressibility of the chambers. 
     When the heel chamber  12  is being compressed, as shown in the diagram of  FIG. 2   a , gas  18  may exit output line  14  and go through a check or one-way valve  21 . From valve  21 , gas  18  may flow into line or tube  26  to energy converter  25 . Gas  18  is not necessarily able to flow through valve  21  towards chamber  12 . Converter  25  may instead be an energy storage device or a combination of an energy converter and storage device. 
     When the heel chamber  12  is being decompressed, as shown in the diagram of  FIG. 2   b , gas  18  may be drawn in from energy converter  25  through line or tube  27  and to a check or one-way valve  22  and enter input line  15  to expanding chamber  12 . Gas  18  is not necessarily able to flow through valve  22  away from chamber  12 . 
     When the toe chamber  13  is being decompressed, as shown in the diagram of  FIG. 2   a , gas  18  may be drawn in from energy converter  25  through line or tube  27  and a check or one-way valve  24  and enter input line  17  to expanding chamber  13 . Gas  18  is not necessarily able to flow through valve  24  away from chamber  13 . 
     When the toe chamber  13  is being compressed, as shown in the diagram of  FIG. 2   b , gas  18  may exit output line  16  and go through a check or one-way valve  23 . From valve  23 , gas  18  may flow into line or tube  26  to converter  25 . Gas  18  is not necessarily able to flow through valve  23  towards chamber  13 . 
       FIG. 3  show the present system implemented in footwear. Even though two pieces of footwear are shown in the Figure, in some cases the system may be implemented in just one piece of footwear or only one shoe  11  per person. The present system might even be implemented with just one chamber. The system may be implemented in footwear for a kind of animal such as a horse. 
     In a typical walking step, the gas chamber  12  on the back (heel) may first be compressed during heel landing  31  as indicated in  FIG. 3 , and then the front chamber  13  may be compressed during the takeoff push  32 . The force in both compressions is comparable to the body weight, and their duration may be about 0.5 to 1 second, depending on the walking speed. The peak pressure for a 72 kg (˜159 lbs) body weight and a 3×3 cm 2  (˜1.4 in 2 ) compression area, may be about 784,500 Pa (˜114 psi). For a compression distance of 3 mm (0.118 in), the volume displacement may be 2.7 cm 3  (˜0.165 in 3 ), corresponding to 2.1 J (2.1 watt sec) per compression and 4.2 J (4.2 watt sec) per step. From this estimate, 1 W (1 J/sec) average power at normal walking (2 steps/sec) only needs a minimum conversion efficiency of 12 percent, which is a moderate goal. 
     The pneumatic rectification circuit  20  using four check valves  21 ,  22 ,  23  and  24  may direct the high pressure gas to a turbine  28  with a nozzle  29  for both compressions, so the turbine  28  is always driven in one direction. The turbine  28  may be connected to an electric generator  33  with a shaft  34 . Electric current may be provided by leads  35  from the generator  33 . The leads  35  may be connected to an electrical device  36  such as a cell phone, a PDA, storage, a computer, a light, or other item. 
     The microturbine generator unit  25 , by virtue of its small size (i.e., about 1 inch in length and 0.5 inch or so in diameter), may be placed in various locations in the footwear  11 , depending on overall requirements and other specifications. If the unit  25  is not in sole  19 , a pneumatic connection may be made via small tubings  26  and  27  to other locations for unit  25 . There may be other items (e.g., a pump for filling a pressure tank with another medium for reserve energy, a massager, pump, and so forth) which may be driven by pressured gas  18  from the footwear  11 . 
     In the present specification, some of the matter may be of a hypothetical or prophetic nature although stated in another manner or tense. 
     Although the invention has been described with respect to at least one illustrative example, many variations and modifications will become apparent to those skilled in the art upon reading the present specification. It is therefore the intention that the appended claims be interpreted as broadly as possible in view of the prior art to include all such variations and modifications.