A device for use in a shoe includes a first foot, a second foot, a third foot, a fourth foot, a first flexible leg, a second flexible leg, a third flexible leg, and a fourth flexible leg. The first flexible leg extends from the first foot and is curved. The second flexible leg extends from the second foot and is curved. The third flexible leg extends from the third foot and is curved. The fourth flexible leg extends from the fourth foot and is curved. The first flexible leg, second flexible leg, third flexible leg, and fourth flexible leg are joined together with each other at a common area. The first flexible leg, second flexible leg, third flexible leg, and fourth flexible leg are configured to store energy when a force is applied to the common area, and to return energy when the force is removed from the common area.

A vibration isolator can be configured to provide improved vibration isolation performance, such as in connection with a bicycle saddle. The bicycle saddle can be operatively connected to a bicycle frame. The vibration isolator can be located within a portion of the bicycle frame. The vibration isolator can be operatively positioned with respect to the bicycle saddle. The vibration isolator being configured to exhibit a non-linear stiffness profile. The non-linear stiffness profile can include a region of quasi-zero stiffness. The vibration isolator including a plurality of spring members arranged in a stack.

A lattice structure and system for absorbing energy, damping vibration, and reducing shock. The lattice structure comprises a plurality of unit cells, each unit cell comprising a plurality of rib elements with at least a portion of the rib elements including a solid bendable hinge portion for converting energy into linear motion along a longitudinal axis of the respective rib element.

A power transmission device includes an inertia ring, a plate, a plurality of first bolts, a torque transmission member, and a plurality of second bolts. The inertia ring has an annular shape. The inertia ring includes a plurality of through holes. The plurality of through holes are disposed at intervals in a circumferential direction. The plate is disposed on a first side with respect to the inertia ring in an axial direction. The plurality of first bolts are screwed into the plurality of through holes from the first side to fasten the plate to the inertia ring. The torque transmission member is disposed on a second side with respect to the inertia ring in the axial direction. The plurality of second bolts are screwed into the plurality of through holes from the second side to fasten the torque transmission member to the inertia ring.

A leaf spring device includes a plurality of leaf springs, in which a restricting protrusion is provided on one leaf spring, a recessed part is formed on the other leaf spring, a first side surface of the restricting protrusion and a third side surface of the recessed part face each other in a plate width direction, a second side surface of the restricting protrusion and a fourth side surface of the recessed part face each other in the plate width direction, a first inclined surface is formed on one of the first and third side surfaces to be further away from the other thereof from a central portion toward a first direction, and a second inclined surface is formed on one of the second and fourth side surfaces to be further away from the other thereof from the central portion toward a second direction.

An elastic wave cloaking lattice-based metamaterial for cloaking an object within a void includes a lattice of connected unit cells arranged to form a void, each unit cell comprising a mass and a plurality of connecting springs, the mass coupled by the plurality of connecting springs to masses in adjacent unit cells, the plurality of connecting springs comprising at least two large springs of a first length and at least two short springs of a second length, the first length greater than the second length, the springs and masses having relational and mechanical characteristics to facilitate elastic wave cloaking in the totality of the lattice. The lattice as a whole has metamaterial properties resulting from the positional relationship and mechanical properties of masses and connecting springs of the unit cells such that the lattice at least partially cloaks an object or material portioned within the void from elastic waves.

An elastic wave cloaking lattice-based metamaterial for cloaking an object within a void includes a lattice of connected unit cells arranged to form a void, each unit cell comprising a mass and a plurality of connecting springs, the mass coupled by the plurality of connecting springs to masses in adjacent unit cells, the plurality of connecting springs comprising at least two large springs of a first length and at least two short springs of a second length, the first length greater than the second length, the springs and masses having relational and mechanical characteristics to facilitate elastic wave cloaking in the totality of the lattice. The lattice as a whole has metamaterial properties resulting from the positional relationship and mechanical properties of masses and connecting springs of the unit cells such that the lattice at least partially cloaks an object or material portioned within the void from elastic waves.

A wave spring unit comprising a plurality of annular wave-spring elements stacked vertically along an axial direction, which is characterized in that each of the annular wave spring elements of the wave spring unit comprises crest portion and trough portion formed alternately in a horizontal axial direction; said crest portion and trough portion of adjacent vertically annular wave spring elements are positioned opposite each other; said adjacent vertically annular wave spring elements have the same or different from each other in at least one physical parameter selected form a strip thickness, a strip diameter, a strip weight, strip shape, wave contact number, edge shape, overall shape of the spring and a combination of wave and helical spring; and the wave spring unit has a maximum compression up to 30.2 mm and is capable of bearing load up to 2680.2 N.

A wave spring unit comprising a plurality of annular wave-spring elements stacked vertically along an axial direction, which is characterized in that each of the annular wave spring elements of the wave spring unit comprises crest portion and trough portion formed alternately in a horizontal axial direction; said crest portion and trough portion of adjacent vertically annular wave spring elements are positioned opposite each other; said adjacent vertically annular wave spring elements have the same or different from each other in at least one physical parameter selected form a strip thickness, a strip diameter, a strip weight, strip shape, wave contact number, edge shape, overall shape of the spring and a combination of wave and helical spring; and the wave spring unit has a maximum compression up to 30.2 mm and is capable of bearing load up to 2680.2 N.

A structure having limited supportable portions has been difficult to isolate from vibration in the direction in which a load is applied. A base isolation apparatus includes a Z-axis base isolation unit, an X-axis base isolation unit, and a Y-axis base isolation unit. The base isolation unit includes a vibration-source connector, an isolated-object connector, a lock device disposed between the isolated-object connector and the vibration-source connector for switching between a state of fixing the isolated-object connector and a state of making it movable, a distance recovery device for generating a force to cause an amount of change in distance to approach zero, depending on the amount of change, and a vibration damper for generating a force in an orientation of hindering the change, depending on the rate of change in distance.