The present application claims priority to and benefit from the filing date of U.S. provisional application serial No. 62/973771 filed 24/10/2019 and is U.S. patent No. 10525307 (which is a continuation of U.S. patent application serial No. 15/609004 filed 30/5/2017), U.S. patent No. 10071288, a continuation-in-part of U.S. patent application serial No. 16/125696 filed 9/2018, which are incorporated herein by reference in their entirety.
Background
There has been a need for a swimming fin that will perform optimally during both low and high thrust situations. Such a swimming fin may be highly flexible and provide an optimal angle of attack during low kick frequency and low thrust conditions, and, however, during high kick frequency and high thrust conditions, the swimming fin will tend to behave like a relatively stiff swimming fin. Such a swimming fin may also provide a smooth curved blade flexing profile, resulting in a laminar water flow over the swimming fin.
The prior art is replete with a variety of fin designs as follows: it combines a foot bag with side rails and a propulsion blade, wherein the aim is to provide maximum propulsion and agility while minimizing the labour expended by the user. It is desirable to provide an optimum angle of attack of the fin blades during a forward shallow kicking power stroke, while generally allowing the fin blades to generate a water flow line during a return stroke. Prior art designs are typically too stiff or flexible for a given application, or have contours or profiles that result in inefficient fluid dynamics as follows: wherein the angle of attack is poor and/or water spills over on the sides of the blade or hydrofoil and wherein such a design causes fluid eddies and/or turbulence which negates the lift or propulsion forces resulting in a reduced finning efficiency with a corresponding increase in fatigue. During scuba diving, propulsion efficiency is important in order to prolong underwater stay time and minimize energy consumption and air consumption while moving through the water with less fatigue on the legs.
A variable called "attack angle" is defined as the relative angle that exists between the actual alignment of the upcoming flow or direction of swimmer motion and the alignment of the fin blades in the length direction. The correct angle of attack optimizes the conversion of the swimmer's kicking energy while providing thrust or propulsion through the water. The optimum blade angle of attack is desirable during both rapid and slow kick frequencies, and, in general, prior art fins do not achieve the optimum angle of attack under both extreme conditions of kick effort. These two distinct and opposite modes of operation traditionally require different fin hardnesses for a given angle of attack due to the different bending force requirements of the fin blade or fin track during the two different modes of operation.
The present invention provides an optimum fin blade angle of attack for a swimming fin during slow non-aggressive kicking, while at the same time the fin blade angle of attack may be limited by the hinged fin ridge during aggressive high kicking frequency and high thrust operation to ensure efficient operation with maximum laminar flow. The swim fin may be molded from a highly flexible, low durometer material that cooperates with the hinged fin ridge to prevent high angles of attack without the fin blade's bending radius being allowed to collapse and fold or "flatten" beyond a given predetermined flex angle. This results in a highly flexible swimming fin during low and moderate exertion, such that the user's ankle, foot, and achilles tendon are not stressed, and, however, if the user demands more, the blade attack angle can be strictly enforced. In addition, the high swimming fin deflection potential with a predetermined maximum blade attack angle allows the user to change direction quickly (particularly when agility is required as the user must twist as required during a critical diving or swimming event).
Furthermore, an additional benefit of the present invention is that the torsional stiffness of the fin is substantially balanced at the left and right sides of the blade due to the bending limit constraints imposed on the fin track by the hinged ridges, and thus efficiency can be obtained by substantially eliminating the swimming fin twist that occurs when a user kicks. In this way, proper flow on the fin blade surface can be generally achieved without the need for sideways overflow power, and the swimming fin can track more straight without unwanted twisting and turning by the user, thus wasting energy. The result is a highly stable and straight kicking experience while achieving steering as desired.
Drawings
So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.
It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
Figure 1 is a perspective view of a swimming fin.
Fig. 2 is a bottom perspective view of the swimming fin shown in fig. 1.
FIG. 3 is a perspective view of the base member of the swimming fin shown in FIG. 1.
Fig. 4 is a perspective view of the base of the swimming fin and fin ridge member shown in fig. 1.
Fig. 5 is a perspective view of the fin ridge segment of the swimming fin shown in fig. 1.
Fig. 6A is a side view of a fin ridge member illustrating the connection joint between fin ridge segments of the swimming fin shown in fig. 1, with the fin ridges in a linear orientation.
Fig. 6B is a side view of a fin ridge member illustrating the connection joint between fin ridge segments of the swimming fin shown in fig. 1, with the fin ridges in an articulated orientation.
Fig. 7A is a side view of the fin ridge of the swimming fin shown in fig. 1, illustrating the fin ridge in a straight orientation.
Fig. 7B is a side view of the fin ridge of the swimming fin shown in fig. 1, illustrating the fin ridge in an articulated orientation.
Fig. 8 is an exploded perspective view of the spine attachment member of the swimming fin shown in fig. 1.
Fig. 9 is a cross-sectional view taken along line 9-9 of fig. 7A.
FIG. 10A is an exploded perspective view of a second embodiment of a swimming fin.
Fig. 10B is a partial perspective view of the fin ridge of the swimming fin shown in fig. 10A.
FIG. 11 is a perspective view of a third embodiment of a swimming fin.
Fig. 12 is an exploded perspective view of the swimming fin shown in fig. 11.
Detailed Description
Referring first to FIG. 1, a swimming fin is generally identified by reference numeral 100. The swimming fin 100 may include a complete boot or shoe or an open foot pocket 110 shown in fig. 1 for receiving a swimmer's foot. A heel strap may be provided to secure the swimmer's foot in foot bag 110. The fin blades 114 may extend from the foot pockets 110. The fin blades 114 may include a substantially planar surface for directing water flow across the swim fin 100. The fin track 116 may extend along the lateral edges of the fin blades 114. Foot bag 110 may include a venting area 118 to minimize slow descent (parachute) as it moves through water and also to minimize suction as the user's foot is removed from foot bag 110.
Referring now to fig. 3, the swimming fin 100 may include a relatively rigid base mount 120, and the base mount 120 may be bonded to the foot pouch 110 during the injection molding process. The base 120 may be constructed of a stronger or more rigid material such as, but not limited to, nylon, Delrin, polyethylene, polycarbonate, polypropylene, or other polymers, as compared to the relatively flexible fin blades 114 (which may be constructed of a composite of materials such as, but not limited to, rubber, monoporene, Santoprene, thermoplastic rubber, and/or other synthetic materials and/or materials including carbon fiber). During the injection molding process, the base 120 may be inserted into the molding tool and the pliable fin blades 114 and foot pockets 110 overmolded in a manner known in the art. In the case where the swim fin 100 is substantially constructed of natural rubber or other material that is not suitable for injection molding, the base 120 may be inserted into the compression cavity during compression molding prior to forming the swim fin 100.
Referring again to fig. 1, a fin ridge 122 may be disposed in each of the fin tracks 116. Fin ridge 122 may include a plurality of articulated fin ridge segments 124 in a serial or linear configuration. Each fin segment 124 may be generally described as including a head portion 126, a neck portion 127, and a socket portion 128, best shown in fig. 5. The neck portion 127 may include an oppositely facing planar surface 130 and a planar surface 131 extending from the head portion 126 to the socket portion 128.
The socket portion 128 of each fin ridge segment 124 may include a pair of spaced apart tines 132, the tines 132 defining a gap 134 therebetween that opens into a cavity 136. Tines 132 may include planar surfaces 133 and planar surfaces 135 that face each other. The cavity 136 may be sized and configured for cooperative engagement with the head 126 of the spine segment 124 to form a connection joint 138 between adjacent fin spine segments 124. The fin ridges 122 may be assembled to a predetermined length and ridge articulation. The interaction of the fin ridge segments 124 contributes to the overall articulation of the fin ridge 122. The fin ridge 122 may taper downward toward its distal end.
The articulation at each connection joint 138 may be limited by impact between planar surface 130 of neck portion 127 and planar surface 133 of tines 132 in a first articulation direction. Articulation in the second direction may be limited by impact between planar surface 131 of neck portion 127 and planar surface 135 of tines 132. For example, when the overall ridge hinge angle a1 is zero degrees (0 °) or in the 'toe up' direction and the fin ridge 122 is longitudinally straight as illustrated in fig. 6A, the planar surfaces 130 and 133 of adjacent fin ridge segments 124 collide in the first hinge direction. When fin ridge 122 is hinged at an overall angle a2 of approximately sixty degrees (60 °) in a second hinge direction or in a 'toe down' direction, planar surface 131 and planar surface 135 of fin ridge segment 124 collide. In this particular example where the fin ridge 122 includes five connection joints 138 between fin ridge segments 124, the maximum pivot or rotation at each connection joint 138 is zero degrees (0 °) in the 'toe up' a1 direction and twelve degrees (12 °) in the 'toe down' a2 direction. However, the maximum pivot range at any connection joint 138 in the 'toe up' direction or the 'toe down' direction need not be equal for all fin ridges 122. Further, the "toe-up" and "toe-down" allowable hinge angles a1 and a2, respectively, may be any acute angle less than ninety degrees (90 °). For example, in some examples, the 'toe-up' overall articulation of the artificial spine may be approximately twenty-five degrees (25 °).
Referring again to fig. 3, the base pedestal 120 may include a relatively flat bottom surface 121 and sidewalls 123. The pair of fin ridge supports 125 may be connected to the base 120 by a plurality of rib members 140. Base chassis 120 may include a plurality of raised areas 142 on bottom surface 121 and the like to minimize slippage of a user's feet when positioned in foot pocket 110.
The fin spine support 125 may define a substantially tubular cavity 144, the cavity 144 configured to receive a fin spine joint 146, the fin spine joint 146 connecting the fin spine 122 to the base mount 120. The fin spine joint 146 may include an elongated body 148 best shown in fig. 8. One end of the elongate body 148 may include a head 150 and a neck portion 152 substantially similar to the head 126 and neck portion 127 of the fin ridge segment 124, the head 150 and neck portion 152 for pivotally connecting the fin ridge 122 to the base mount 120. The fin link 146 may include a hollow chamber 154 that houses a leaf spring 156. An outwardly biased pin 158 may be located proximate the distal end of the leaf spring 156. The pins 158 protrude through aligned openings 160 on opposite sides of the fin spine link 146. The fin ridge 122 may be removably connected to the base mount 120 by: the fin links 146 are inserted into respective fin spine supports 125 and the openings 160 of the fin spine links 146 are aligned with corresponding holes 162 in the fin spine supports 125 such that the outwardly biased pins 158 extend through the holes 162. Heel strap post 164 may be molded with base chassis 120. Heel strap post 164 provides a connection point for heel strap connection hardware 166 in a manner known in the art. The fin ridge 122 may be removed when the pin 158 is pressed inward and retracts the fin ridge 122 from the fin track 116.
During fin kicking, the fin ridge 122 generates a cantilevered bending moment that is transferred to the base 120 through the fin ridge support 125, which is then distributed throughout the foot pocket 110. Base chassis 120 supports foot bag 110 such that foot bag 110 is substantially undeformed. A sheet region may be provided along a top portion of foot pocket 110 to minimize the stiffness of foot pocket 110 near the upper surface of the user's tarsometatarsal joints and/or metatarsals of the foot.
Referring again to fig. 1 and 2, in one example, the fin track 116 may include a series of notched outer portions or windows 170. The fin ridge segment 124 may be provided with a reference mark 172, the reference mark 172 being visible, and the reference mark 172 aligning with a hash mark 174 on the fin track 116 when the fin ridge 122 is properly installed, particularly when the swimming fin 100 is configured for asymmetric bending of the fin ridge 122.
Three-dimensional fin blade scooping may improve efficiency and minimize water spillage on the fin rails 116, and may be optimized by designing the draft angle of injection molding of the
fin ridge segments 124 to be relative to the design blade' attack angleTo provide. In this example, the reader will note that the
fin ridge segment 124 may have a draft angle that originates at the injection molding tool operating split line 180 (shown in fig. 5) of typically one-half of a degree
(shown in fig. 9). This minimum draft angle required during the injection molding process of the
fin ridge segment 124
The resulting dynamic scooping of the
fin blades 114 has a scooping radius of approximately six inches at the trailing edge of the
fin blades 114 allows for an effective lateral articulation of each
fin ridge 122 of approximately four degrees, which may be optimal for an effective 3D blade scooping action. Further optimization of blade scooping may be achieved where the
fin track 116 is molded to diverge when the
fin blades 114 are flat and stationary, and as a result, the
fin ridges 122 diverge laterally at their distal ends, as illustrated in fig. 4. In such a configuration, the
fin ridges 122 converge at their distal ends as the opposing draft angles of the
fin ridge segments 124 collide laterally during a kicking action. Depending on the size of the
swimming fin 100, different fin ridge draft angles may be preferred in order to maximize efficiency without introducing significant delays in the reaction time for blade extraction reversal to occur during fin kick reversal.
Referring now to fig. 10A and 10B, a second illustrative embodiment of a swimming fin is generally identified by the reference numeral 200. As indicated by using common reference numerals, the swimming fin 200 is similar to the swimming fin 100 described above. The swimming fin 200 may include a full boot or shoe or an open foot pocket 110 for receiving a swimmer's foot. A heel strap may be provided to secure the swimmer's foot in foot bag 110. The fin blades 214 may extend from the foot pouch 110. The fin blades 214 may include a substantially planar surface for directing water flow across the swimming fin 200. The fin track 216 may be disposed within a laterally intermediate region of the fin blade 114. The fin track 216 may define a longitudinal cavity configured to receive the fin ridge 218. Fin ridge 218 may include a cable 220 and a plurality of fin ridge segments 222 threaded onto cable 220. Fin ridge segment 222 may be loosely captured between lugs 224 that are fixedly crimped at the distal end of cable 220. The fin ridge 218 may flex through an angle a, as shown in fig. 10B.
Referring now to fig. 11 and 12, a third illustrative embodiment of a swimming fin is generally identified by the reference numeral 300. As indicated by using common reference numerals, the swimming fin 300 is similar to the swimming fin 100 described above. The swimming fin 300 may include fin blades 310 constructed of, for example, but not limited to, a thermoplastic such as polyethylene. The base 312 may be integrated with the fin blade 310 without overmolding. The foot boot 314 may be constructed of a soft, low durometer material such as, but not limited to, rubber or Monprene. The foot shoe 314 may be directly bonded to the fin blade 310. Irregular surfaces, holes 316, and the like can help bond the bootie 314 to the base 312. The fin blades 310 may include a substantially planar surface for directing water flow across the swimming fin 300. The fin track 318 may extend along the lateral edges of the fin blade 310. The fin track 318 may define a longitudinal cavity 320 configured to receive the fin ridge 218. Fin ridge 218 may include a cable 220 and a plurality of fin ridge segments 222 threaded onto cable 220. Fin ridge segments 222 may be captured between lugs 224 that are fixedly crimped at the distal end of cable 220. The longitudinal cavity may be partially filled with mineral oil, vegetable oil, or other ecologically friendly fluid in order to minimize potential galvanic corrosion activity that may be present in the brine. The fin ridge 218 may be inserted into the longitudinal cavity 320, after which the longitudinal cavity 320 may be sealed with a plug 322.
While the preferred embodiments of the present invention have been illustrated and described, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.