Abstract: A constant force spring system to achieve a substantially constant force curve, includes top and bottom load surfaces separated by a load compression distance therebetween; a main spring; at least one auxiliary linear spring acting on a last portion of the load compression distance to prevent load compression; a spreading linkage acting between the top load surface and the bottom load surface to prevent load compression thereof; and link hinges connecting the links, wherein the spreading linkage.

Abstract: A futuristic shoe with true energy return based on enhanced heel-lift, optimized shoe springs (40% reduction in maximum foot impact), practical precise automatic electronic gear changers, novel powerful shoe impact chargers, improved pulley electronic actuators, novel low-impact much stronger springs (featuring the novel use materials such as Kevlar, Spectra Shield, and fiberglass), novel remarkably stronger, more flexible, and tougher structures, and multiple designs for enhanced heel-lift and to prevent excessive toe sink. These designs require linkages and two improved hinges—one with enhanced natural hinges and a second with tied cogged hinges. There is a rotating-arms enhanced optimal spring, which when combined with the tied cogged hinges, results in optimal foldable arrays for deployment in outer space—and which gives a smart energy return knee brace.

Abstract: A futuristic shoe with true energy return based on enhanced heel-lift, optimized shoe springs (40% reduction in maximum foot impact), practical precise automatic electronic gear changers, novel powerful shoe impact chargers, improved pulley electronic actuators, novel low-impact much stronger springs (featuring the novel use materials such as Kevlar, Spectra Shield, and fiberglass), novel remarkably stronger, more flexible, and tougher structures, and multiple designs for enhanced heel-lift and to prevent excessive toe sink. These designs require linkages and two improved hinges—one with enhanced natural hinges and a second with tied cogged hinges. There is a rotating-arms enhanced optimal spring, which when combined with the tied cogged hinges, results in optimal foldable arrays for deployment in outer space—and which gives a smart energy return knee brace.

Abstract: A futuristic shoe with true energy return based on enhanced heel-lift, optimized shoe springs (40% reduction in maximum foot impact), practical precise automatic electronic gear changers, novel powerful shoe impact chargers, improved pulley electronic actuators, novel low-impact much stronger springs (featuring the novel use materials such as Kevlar, Spectra Shield, and fiberglass), novel remarkably stronger, more flexible, and tougher structures, and multiple designs for enhanced heel-lift and to prevent excessive toe sink. These designs require linkages and two improved hinges—one with enhanced natural hinges and a second with tied cogged hinges. There is a rotating-arms enhanced optimal spring, which when combined with the tied cogged hinges, results in optimal foldable arrays for deployment in outer space—and which gives a smart energy return knee brace.

Abstract: 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.