Method for creating consistent large scale blade deflections

#1. Field of Invention

#This invention relates to hydrofoils, specifically to such devices which are used to create directional movement relative to a fluid medium, and this invention also relates to swimming aids, specifically to such devices which attach to the feet of a swimmer and create propulsion from a kicking motion.

#2. Description of Prior Art

#FIGS. 1a, 1b, and 1c, show side views of prior art fins having lengthwise tapering blades or load bearing ribs that focus bending at the outer half of the blade and either under deflect on a light kick or over deflect during a hard kick.

#FIGS. 2a and 2b show side views of prior art fins having blades that are able to experience bending between the foot pocket and the first half of the blade and tend to either under deflect during a light kick or over deflect during a hard kick.

#FIGS. 2a and 2b show side view of prior art fins that have blades that are able to bend close to the foot pocket and tend to either under deflect during a light kick or over deflect during a hard kick.

#For increased clarity and reduced repetition, the following specification will primarily refer to three different types of kicking stroke strengths that are used in attempting to reach three different types of swimming speeds. A light kicking stroke, light kick, and light stroke, will mean a kicking stroke. In which the swimmer uses relatively low levels of force to move the fin through the water in an effort to produce slow cruising speeds. A medium kicking stroke, medium kick, and medium stroke will mean a kicking stroke in which the swimmer uses relatively moderate levels of force to move the fin through the water in an effort to produce medium or moderately higher cruising speeds. A hard kicking stroke, hard kick, and hard stroke will mean a kicking stroke in which the swimmer uses relatively high levels of force to move the fin through the water in an effort to produce high swimming speeds. For a scuba diver swimming underwater with the added drag created by full scuba gear, slow cruising speed can be considered approximately 0.75 mph or 1.2 km/h, medium or moderate cruise speeds may be considered to be approximately 1 mph or 1.6 km/h, and high swimming speeds can be considered to be speeds faster than 1.25 mph or 2.0 km/h. Swimmers that are not using full scuba gear or that may be swimming along the surface may experience speeds that vary from this general guideline of speed categories. It should be understood that these definitions are used only to provide a general reference and I do not wish to be bound by them.

#Also, in the following description a number of theories are presented concerning the design and operation methods utilized by the present invention. While I believe these theories to be true, I do not wish to be bound by them.

#FIG. 1 shows three different side views of prior art fins having blades and, or load bearing ribs that taper in thickness along their length. FIG. 1a shows a prior art fin having a blade made from a relatively rigid material, FIG. 1b shows the same prior art fin having a more flexible material used within the blade, and FIG. 1c shows the same prior art fin having a highly flexible material used within the blade. FIG. 1a shows a fin having a foot pocket 100 connected to a blade 102 having a neutral position 104 while the fin is at rest. Broken lines show a light kick blade deflection 106 created as the swimmer uses a light kicking stroke, a medium kick blade deflection 108 created during a medium kicking stroke, and a hard kick blade deflection 110 created during a hard kicking stroke. Because blade 102 is made of a rigid material, deflections 106, 108, and 110 are all under deflected to produce a sufficiently reduced angle of attack to efficiently produce lift. It can be seen that deflections 106, 108, and 110 occur at significantly regular and evenly spaced intervals from neutral position 104. This shows that the relation between the degree of blade deflection to force or load on the blade is highly proportional and occurs in a significantly linear manner. This combines with the rigid blade material to prevent the blade from having consistent large scale blade deflections during use.