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 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 device comprising: (a) a first working arm; (b) a shuttle located on the first working arm, and (c) a bias device; wherein the bias device biases the first working arm when the shuttle is in a first position, and wherein the bias device is free of biasing the first working arm when the shuttle is in a second position.

A spring leaf for a leaf spring (1) has an upper side (13), a lower side (14), two lateral sections extending between the upper side (13) and the lower side (14), a longitudinal axis (15), a section plane (III) extending perpendicularly to the upper side (13) and lower side (14) and through the longitudinal axis (15), two end sections (3a, 3b), and a middle section (4) extending between the end sections (3a, 3b). The middle section (4) has a clamping region (5). A main tension region (6a, 6b) is provided between at least one of the end sections (3a, 3b) and the clamping region (5), the thickness (S) of which decreases in the direction from the clamping region (5) to the end section (3a, 3b), in particular decreases parabolically. The width (B) of the main tension region (6a, 6b) extending between the section plane (III) and a lateral section of the spring leaf (2) increases over a part of its length or over its entire length in the direction from the end section (3a, 3b) toward the clamping region (5) according to a quadratic function.

A flexible spring element is made of a fibre-reinforced plastics composite material, a functional layer made of a fibre-reinforced plastics composite material being located on each of two mutually opposite sides of a central plane of the flexible spring element. At least one matrix material discharge layer extending parallel to the two functional layers and in a longitudinal direction is arranged in at least one longitudinal portion and has at least a fraction of discharge layer fibres which are oriented differently from the longitudinal direction of the flexible spring element. Within at least one curved portion of the flexible spring element a first volume fraction of flexible spring fibres in the functional layers is smaller, preferably smaller by several % than a second volume fraction of flexible spring fibres in the functional layers within the at least one longitudinal portion.

A flexible spring element is made of a fibre-reinforced plastics composite material, a functional layer made of a fibre-reinforced plastics composite material being located on each of two mutually opposite sides of a central plane of the flexible spring element. At least one matrix material discharge layer extending parallel to the two functional layers and in a longitudinal direction is arranged in at least one longitudinal portion and has at least a fraction of discharge layer fibres which are oriented differently from the longitudinal direction of the flexible spring element. Within at least one curved portion of the flexible spring element a first volume fraction of flexible spring fibres in the functional layers is smaller, preferably smaller by several % than a second volume fraction of flexible spring fibres in the functional layers within the at least one longitudinal portion.

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 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.

Provided is a composite material capable of measuring bending deformation, the composite material including: a first conductive composite body that is bendable; a dielectric body that is bendable and compressible; and a second conductive composite body that is bendable, wherein the first conductive composite body and the second conductive composite body are respectively stacked on both surfaces of the dielectric body, and heights of the first conductive composite body and the second conductive composite body from the dielectric body are different from each other.

Provided is a composite material capable of measuring bending deformation, the composite material including: a first conductive composite body that is bendable; a dielectric body that is bendable and compressible; and a second conductive composite body that is bendable, wherein the first conductive composite body and the second conductive composite body are respectively stacked on both surfaces of the dielectric body, and heights of the first conductive composite body and the second conductive composite body from the dielectric body are different from each other.