Other

Alan Perry

Peter H Muller

Peter H M&uuml;ller

An enhanced swim fin is provided comprising a flipper blade having an increased effective surface area during movement in a first direction, and a decreased effective surface area during movement in a second direction. The swim fin preferably comprises a staged opening during movement in the first direction, in which the opened flipper blade provides increased flexion as the effective surface area is increased. The swim fin preferably comprises a staged closing during movement in the second direction, in which the opened flipper blade provides decreased flexion as the effective surface area is decreased. In some embodiments of the staged swim fin, a central hinge, generally located longitudinally along the blade on the fin, provides staged opening and flexion. Various embodiments provide fin opening and closing for either forward or backward kicks. The enhanced swim fin is typically attached to a foot, such as for performance, for training, or for physical therapy. Alternate embodiments of the expandable fin blade may be attached to a hand or to an oar or paddle shaft.

Staged expandable swim fin

An expandable swim flipper includes a blade having at least an expandable portion thereof. The expandable portion radially expands in response to water resistance directed to a first surface of the blade. The surface area of the flipper is correspondingly increased to propel a swimmer at a faster rate through the water. The expandable portion radially contracts in response to water resistance directed to a second surface of the blade. The surface area of the flipper is correspondingly reduced, and is thereby subject to decreased water resistance. In a first preferred embodiment of the invention, the flipper blade is formed of expandable lateral members joined to a central member having a constant width. In a second, equally preferred embodiment, the flipper blade is formed of lateral members having a constant width and joined to an expandable central member. In a third, equally preferred embodiment of the invention, the flipper blade is expandable over its entire width. Rigid axial supports, or vertical flexors may be provided to supply additional structural support to the swim flipper.

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San Jose, CA, United States of America

Alan Perry