Retractable swim fin

Improved swimming efficiency and safety in a water environment is achieved with the use of retractable swim fins having a web-like member rotatably interconnected to a shoe-like member. Latching means secure the web-like member to the shoe-like member in a downward swimming position. Releasing means permit the web-like member to rotate to an upward walking position. Pressure from a swimmer's foot returns and latches the web-like member to the downward position.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention generally relates to a swim fin. More particularly, 
the present invention relates to a retractable swim fin which increases 
swimming efficiency and which, when retracted, increases walking 
efficiency. 
2. Description of the Prior Art 
In accordance with the prior art a swim fin may be defined as an area 
expanding appendage which, when attached to a foot of a swimmer, enables 
the swimmer to generate more propulsive force through water. For optimum 
benefit, a swim fin generally has from 5 to 50 times the area of the 
swimmer's foot. 
Various swim fin arrangements have been proposed and utilized to generally 
provide a more efficient swim fin. Representative of the prior art are the 
swim fin and swim shoe arrangements disclosed in U.S. Pat. Nos. 2,729,832 
(Schmitz), 2,903,719 (Wozencraft), 2,980,926 (Wolshin), 3,082,442 
(Cousteau), 3,171,142 (Auzols), 3,268,927 (Markowitz), 3,302,223 
(Ciccotelli), 3,665,535 (Picken), 4,025,977 (Cronin), 4,209,866 
(Loeffler), 4,250,584 (Korn), 4,657,515 (Ciccotelli), and 4,689,029 
(Ciccotelli). 
The patents issued to Schmitz, Auzols, Picken, Cronin, Loeffler, and 
Ciccotelli generally involve the angular orientation of a fin relative to 
the plane of a foot or the longitudinal axis of a lower leg of a swim fin 
user. While the patents issued to Wolshin and Markowitz generally involve 
footgear with a swim fin disposable either in a walking position or a 
swimming position. The patent issued to Cousteau generally involves a swim 
fin comprising a footgear section, a propelling section, and a 
interconnecting section having less rigidity than the footgear and 
propelling sections; whereas the patent issued to Korn generally involves 
a collapsable swim fin. And lastly, the patent issued to Wozencraft 
generally involves a forwardly projecting swim fin hingedly connected to a 
swim shoe so that the swim fin may be swung rearwardly of the swimmer's 
foot. Basically, most of the cited swim fin arrangements comprise a 
propelling section angularly oriented with respect to the plane of a foot 
or the longitudinal axis of a lower leg of a swim fin user and a footgear 
section integral with the propelling section. 
SUMMARY OF THE INVENTION 
As indicated above, a swim fin generally has from 5 to 50 times the area of 
the swimmer's foot. While this large area, protruding as a fan-shaped 
extension similar to a duck's foot, is extremely helpful for propelling 
the swimmer in water, such extension is extremely awkward and even 
dangerous when the swimmer attempts to walk with the swim fins in place. 
The angular projection of a swim fin from a swimmer's leg required for 
optimum swimming efficiency causes an imbalance of the natural standing 
posture of a swim fin wearer. Additionally, the large protruding fin area 
in front of each foot tends to strike and become caught in all manner of 
objects near the feet. And worst of all, the large fin protrusion on one 
foot tends to be stepped upon by the other foot when walking is attempted, 
pitching the swim fin wearer forward and preventing the quick-foot 
response which usually prevents loss of balance. 
Falls are particularly troublesome and dangerous when aboard moving boats 
or on narrow docks where the probability of falling into the water is 
great. This undesirable situation is often acervated when a swimmer is 
wearing heavy gear, for example, scuba gear, where falling can cause 
serious injury or even death by drowning if the scuba gear is partially 
disassembled at the time of a fall into water. Furthermore, large 
protruding swim fins can be a major hindrance when a swim fin wearer walks 
on any underwater surface because the swim fins tend to stir-up sediment 
on the bottom. This can make it difficult for the swim fin wearer to see 
sharp objects or to avoid dangerous sea life. 
In accordance with the teachings of the present invention a retractable 
swim fin is provided which comprises a shoe-like member or boot with a 
foot receivable pocket adapted for attaching the retractable swim fin to a 
foot of a swimmer's lower leg. A web for providing propulsive thrust in a 
water environment is hingedly or pivotally connected to the shoe-like 
member or boot. Conventional latching means secures the web to the 
shoe-like member or boot in a downward swimming position. Latch releasing 
means permit the web to pivot to an upward walking position parallelly 
adjacent to the front side of a leg of the swimmer. In this upward 
position the wearer can stand or walk easily and safely. A quick kick by 
the wearer's foot underwater returns and latches the web into the 
conventional downward position for further swimming activities. 
The above and other advantages and attainments of the present invention 
will become apparent to those skilled in the art upon a reading of the 
following detailed description when taken in conjunction with the drawings 
wherein there is shown and described an illustrative embodiments of the 
invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In the following description, like reference characters designate like or 
corresponding parts throughout the several views of the drawings. Also in 
the following description, it is to be understood that such terms as 
"forward", "rearward", "left", "right", "upwardly", "downwardly", and the 
like, are words of convenience and are not to be construed as limiting 
terms. 
Referring now to the drawings, and particularly to FIGS. 1 and 2, there is 
illustrated a retractable swim fin, generally designated by the numeral 10 
and constituting the preferred embodiment of the present invention. In its 
basic components, retractable swim fin 10 includes a shoe-like member 12 
and a web-like member 14. Web-like member 14 is pivotally and springingly 
interconnected to shoe-like member 12, which is more fully described 
below. 
Retractable swim fin 10 is securable to a lower leg at a swimmer's foot 16 
by means of shoe-like member 12 which comprises a foot receiving pocket 18 
to accommodate the forward portion of swimmer's foot 16 and an adjustable 
strap 20 which fits around the rearward portion of swimmer's foot 16 at an 
ankle. Adjustable strap 20 is pivotally attached to foot receiving pocket 
18 by a pair of diametrically opposed buckles 22 which allow adjustable 
strap 20 to be tightened or loosened about swimmer's foot 16, as required, 
so that adjustable strap 20 in conjunction with foot receiving pocket 18 
secures retractable swim fin 10 to swimmer's foot 16. 
As indicated above, web-like member 14 is pivotally and springingly 
interconnected to shoe-like member 12. This is accomplished by having a 
pair of diametrically opposed pivot pins 24, which are affixed to 
shoe-like member 12 in a downward and rearward location of shoe-like 
member 12, project through holes 26 in web-like member 14 in a rearward 
location of web-like member 14, and by fastening web-like member 14 to 
shoe-like member 12 by means of a pair of releasable fasteners 28. 
Interposed between shoe-like member 12 and web-like member 14 are a pair 
of diametrically opposed spiral springs 30 which interconnect shoe-like 
member 12 and web-like member 14 so that the tension of spiral springs 30 
causes web-like member 14 to pivot on pivot pins 24 and rotate toward the 
front of a swimmer's lower leg. However, the rotation of web-like member 
14 is stopped before web-like member 14 contacts the front of a swimmer's 
lower leg by a pair of diametrically opposed stop pins 32 which are 
affixed to shoe-like member 12 in an upward and rearward location of 
shoe-like member 12. Although the foot-gear section hereinabove described 
comprises a shoe-like member 12 with foot receiving pocket 18 and 
adjustable strap 20, in another embodiment of the present invention 
shoe-like member 12 would be a boot or the like. 
Referring now again to the drawings, and particularly to FIGS. 3 and 5, 
there is illustrated a pair of guideway-stops 34 and an interposed catch 
36 integral to shoe-like member 12 in a location forward of foot receiving 
pocket 18, with both, the pair of guideway-stops 34 and catch 36, being 
aligned perpendicular to the bottom side of shoe-like member 12. 
Guideway-stops 34 are generally trapezoidal-shaped, each having an upper 
portion of an inner vertical side and a top horizontal side define an 
arcuate segment 38, while an outer vertical side forms with an inner 
vertical side a configuration that is somewhat narrower at a top 
horizontal side than at a bottom horizontal side. Such trapezoidal shape 
of guideway-stops 34 provides a means of aligning web-like member 14 with 
respect to shoe-like member 12. 
Located rearwardly at the backside of web-like member 14 are a pair of 
guideway pins 40 and a pair of guideway-stop pins 42. Guideway pins 40 and 
guideway-stop pins 42 are positioned on the backside of web-like member 14 
so that each guideway pin 40 is aligned toward the outward side of a 
guideway-stop 34 while each guideway-stop pin 42 is directly aligned with 
an arcuate segment 38. Whenever web-like member 14 revolves away from the 
front of a swimmer's lower leg, each guideway pin 40 eventually contacts 
an outward side of a guideway-stop 34. Simultaneously, each guideway-stop 
pin 42 contacts an arcuate segment 38 preventing web-like member 14 from 
further rotation. Thus, whenever web-like member 14 is at an attitude 
substantially parallel to the general axial direction of a swimmer's foot, 
there is minimal lateral or torsional movement of web-like member 14 with 
respect to shoe-like member 12. 
As indicated above interposed between a pair of guideway-stops 34 is catch 
36 integral to shoe-like member 12 in a location forward of foot receiving 
pocket 18, with both, the pair of guideway-stops 34 and catch 36, being 
aligned perpendicular to the bottom side of shoe-like member 12. Catch 36, 
which is part of a latching-releasing mechanism, is an inclined plane with 
its lower portion abutting outwardly from the forward side of foot 
receiving pocket 18 and forming a shoulder with respect to the forward 
side of foot receiving pocket 18. 
Referring yet again to the drawings, and particularly to FIGS. 2, 3, and 4, 
there is illustrated a latchkey 44 which in conjunction with catch 36 
constitute the basic components of a latching-releasing mechanism. 
Latchkey 44 which generally defines the shape of a rectangle is 
constructed from a continuous rod with both rod endpieces outwardly and 
perpendicularly oriented with respect to the two vertical parallel sides 
of latchkey 44 and with both endpieces located at approximately the 
midpoint of the two vertical parallel sides of latchkey 44. (Any 
overlapping rod segment of latchkey 44 is affixed together.) Each rod 
endpiece of latchkey 44 is rotatably positioned in an opening 46 in 
guideway-stop pins 42, which are positioned on the backside of web-like 
member 14, so as to allow latchkey 44 freedom of rotational movement. The 
upper portion of latchkey 44 is exposed above the upper plane of web-like 
member 14. A latchkey spring 48 located at the backside of web-like member 
14 causes the upper portion of latchkey 44 to rotate away from the 
swimmer's foot 16 and causes the bottom portion of latchkey 44 to rotate 
toward the front of swimmer's foot 16. The upper portion of latchkey 44 is 
stopped in its rotational movement by the backside of web-like member 14. 
As can be seen from the above detailed description when taken in 
conjunction with the drawings, retractable swim fin 10 of the present 
invention can be secured to a swimmer's foot 16 with web-like member 14 
either at an attitude substantially parallel to or perpendicular to the 
general axial direction of a swimmer's lower leg. Whenever a user of 
retractable swim fin 10 is walking, whether out of water or under water, 
efficiency and safety is increased when web-like member 14 is retracted. 
And when web-like member 14 is retracted, a user of retractable swim fin 
10 can use a rapid kick motion of the heel of the other foot to rotate 
web-like member 14 forwardly until latchkey 44 first contacts the inclined 
plane and then engages the shoulder of catch 36. When web-like member 14 
is in the swimming position, not retracted, a user of retractable swim fin 
10 can cause web-like member 14 to be released from catch 36 by exerting 
backward pressure from the heel of the other foot onto the exposed portion 
of latchkey 44. 
It is thought that the present invention and many of its attendant 
advantages will be understood from the foregoing description and it will 
be apparent that various changes may be made in the form, construction, 
and arrangement of the parts thereof without departing from the spirit and 
scope of the invention or sacrificing all of its material advantages, the 
form hereinabove described being merely an exemplary embodiment thereof.