US3827095A

US3827095A - Swim fin

Info

Publication number: US3827095A
Application number: US00340223A
Authority: US
Inventors: A Feather
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-03-12
Filing date: 1973-03-12
Publication date: 1974-08-06
Anticipated expiration: 1991-08-06

Abstract

A swim fin having a support strap attachable to the forearm of a user with a lower portion of the strap extending transversely of the under surface of the forearm. Laterally spaced fin members depend from lower portion of the strap and extend rearwardly and outwardly away from each other and move inwardly and outwardly in response to a forward return stroke and a rearward thrust stroke, respectively. Resilient means restrains outward movement of the fin members in proportion to the force applied to produce resistance to the water in proportion to the force applied.

Description

ite l her States Patent [191 I SWIM FIN [76] Inventor: Alec Feather, 1701 Sunrise Ln.,

Fullerton, Calif. 92633 22 Filed: Mar.,12, 1973 21 App1.No.:340,223

[52] [1.8. Cl. 9/307 [51] Int. Cl A631) 31/00 [58] Field of Search 9/301, 303, 305, 307

[56] References Cited UNITED STATES PATENTS 1,760,476 5/1930 Chastenay 9/303 1,821,974 9/1931 LeBlanc 1. 9/303 1,908,184 5/1933 Richmond 9/303 1,983,609 12/1934 Hudson 9/305 X 3,107,371 10/1963 Thompson 9/307 X 3,290,707 12/1966 Montgomery 9/307 FOREIGN PATENTS OR APPLICATIONS Great Britain 9/307 [111 3,827,095 [451 Aug. 6, 1974 Primary Examiner-Trygve M. Blix Assistant Examiner-Gregory W. OConnor Attorney, Agent, or Firm-Jennings, Carter & Thompson [5 7] ABSTRACT A swim fin having a support strap attachable to the forearm of a user with a lower portion of the strap extending transversely of the under surface of the forearm. Laterally spaced fin members depend from lower portion of the strap and extend rearwardly and outwardly away from each other and move inwardly and outwardly in response to a forward return stroke and a rearward thrust stroke, respectively. Resilient means restrains outward movement of the fin members in proportion to the force applied to produce resistance to the water in proportion to the force applied.

6 Claims, 4 Drawing Figures ]I SWIM FIN BACKGROUND OF THE INVENTION This invention relates to a swim fin and more particularly to a swim fin which is attachable to the forearm of a swimmer, surfer, skindiver or others to aid in propelling the body of the user through water.

As is well known in the art to which my invention relates, lifeguards and surfers need the use of their hands. Accordingly, hand paddles and other devices held within the hands are difficult to use. Also, hand paddles and the like heretofore employed have been unsatisfactory due to the fact that it is difficult to adjust the operation of the device to the strength of the individual user. That is, a strong swimmer would need a maximum surface area to present to the water whereas a weaker or tired swimmer would need to present a much smaller surface area to the water.

BRIEF SUMMARY OF THE INVENTION In accordance with my invention, I provide a swim fin having a support strap attachable to the forearm of a user, such as adjacent the wrist, with the lower portion of the strap extending transversely under the forearm. Rearwardly and outwardly extending fin members depend from the under surface of the strap in spaced relation to each other. The fin members are movable inwardly and outwardly in response to a forward return stroke and a rearward thrust stroke, respectively. Outward movement of the fin members is restrained by resilient means to present a surface area to the water in proportion to the force applied. Accordingly, the position of the fin members is adjusted automatically in response to variations in the force applied whereby the operation is adjusted to the strength of the individual user.

DESCRIPTION OF THE DRAWING A swim fin embodying features of my invention is illustrated in the accompanying drawing, forming a part of this application, in which:

FIG. 1 is a side elevational view showing the swim fin in use;

FIG. 2 is a view taken generally along the line 2-2 of FIG. 1;

FIG. 3 is a bottom plane view showing the fiat position that the swim fin assumes when not in use; and,

FIG. 4 is a fragmental view taken generally along the line 4-4 of FIG. 3.

DETAILED DESCRIPTION Referring now to the drawing for a better understanding of my invention, I show a strap-like support member having cooperating

fastening elements

11 and 12 at opposite ends thereof. The

fastening elements

11 and 12 may be in the form of the usual strap and buckle assembly or other fastening devices may be employed. Since such fastening devices for strap-like elements are well known in the art, no further description thereof is deemed necessary. The strap-like member 10 is adapted for attachment to the forearm 13 of a user and is preferably attached adjacent the wrist, as shown in FIG. 1. However, the strap-like member 10 may be attached to the hand or to the forearm at a position inwardly of the wrist.

Formed integrally with the strap-like member 10 are a pair of laterally spaced

fin members

14 and 16 which depend from the lower portion of the strap-like member 10 and extend from a location adjacent the forward portion of said strap-like member rearwardly and outwardly away from each other, as shown in FIGS. 2 and 3 and define therebetween an inverted V-shaped recess having downwardly and outwardly extending sides. The

fin members

14 and 16 and the strap-like member 10 are formed of a resilient material. In actual practice, I have found that many elastomeric materials, such as plastic, rubber and the like having a shore durometer hardness ranging from approximately 50 to 55 is satisfactory.

As shown in FIG. 2, the

fin members

14 and 16 are adapted to move to an inner position with the front edges thereof adjacent and parallel to each other, indicated by dotted lines 14a and 16a, in response to a forward return stroke and are adapted to move to an outer position, indicated by dotted lines 14b and 16b in response to a rearward thrust stroke. According, as shown in FIG. 3, the

fin members

14 and 16 converge forwardly whereby a straight line passing through the front and rear edges of the fin member 14 would intersect a straight line passing through the front and rear edges of the fin member 16 at a point forwardly of the fin members. As shown in FIG. 4, the

fin members

14 and 16 are positioned on the strap-like member 10 whereby they extend at an angle ranging from 10 to 25 away from a vertical plane passing through the strap-like member 10 and extending perpendicular thereto. Accordingly, upon making a forward, return stroke, very little pressure is required to move the

fin members

14 and 16 inwardly to the dotted line positions 14a and 16a. In this position, the fin members extend generally parallel to each other and do not protrude beyond the sides of the forearm 13, thus offering a minimum of resistance on the return stroke. On the rearward or thrust stroke, the

fin members

14 and 16 are adapted to move outwardly a maximum distance of approximately from each other in response to maximum force being applied whereby a maximum surface area is presented to the water for resistance.

By forming the strap-like member 10 and the

fin members

14 and 16 of a resilient material, the resilient material serves as means for restraining movement of the fin members toward the outer dotted line positions 14b and 16b in proportion to the force applied. That is, the

fin members

14 and 16 move outwardly a decreasing angular distance for each increase in force applied to produce resistance to the water in proportion to the force applied. As shown in FIGS. 3 and 4, inwardly projecting stiffening flanges 17 and 18 are provided at the forward and rear edges of the

fin members

14 and 16 whereby it takes a greater force to move the fin members from the solid line position shown in FIG. 2 to the dotted line position shown at 14b and 16b.

From the foregoing description, the operation of my improved swim fin will be readily understood. The strap-like member 10 is attached to the forearm 13 of the user by the

fastening elements

11 and 12 whereby the

fin members

14 and 16 extend outwardly and rearwardly, as shown in FIG. 2. As the arm is moved forward for the return stroke, the

fin members

14 and 16 move to the dotted line positions 14a and 16a whereby they are in alignmentwith the sides of the forearm 13. In this position, the

fin members

14 and 16 do not project beyond the sides of the forearm whereby a minimum of resistance isjoffered during the return stroke.

Upon making a rearward, thrust stroke,'the

fin members

14 and 16 are forced outwardly toward the dotted line positions 14b and 16b. As the force is increased on the thrust stroke, the resilient of the fin members restrains movement toward the outer position in proportion to the force applied. Accordingly, the tin members move outwardly a decreasing angular distance for each increase in force applied to produce resistance to the water in proportion to the force applied. A strong swimmer would thus supply sufficient force to move the

fin members

14 and 16 to the dotted line positions 14b and 16b whereby they are approximately 180 from each other. On the other hand, a weaker or tired swimmer would not be able to exert the required force to move the fin members to the dotted line positions 14b and 16b. Accordingly, the fin members would assume a position between the solid line position and the dotted line position 14b and 16b, depending upon the force exerted. That is, the

fin members

14 and 16 would be automatically adjusted to the proper position to accommodate the force being applied by the swimmer.

From the foregoing, it will be seen that l have devised an improved swim fin. By providing a swim fin which automatically adjusts itself to the force applied by the swimmer, the swim fin is extremely efficient in operation and at the same time does not impair the use of the hands of the swimmer. Also, by providing a swim fin which is attached to the forearm, the swim fin is comfortable to wear and the swimmer is permitted to gain speed with less effort. Furthermore, by forming the swim fin of an elastomer, the entire swim fin may be formed as an integral unit, thus facilitating manufacture.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof.

What I claim is:

1. A swim fin comprising,

a. a strap-like support member adapted for attachment to the forearm of a user with a lower portion of said support member extending transversely of the under surface of said forearm,

b. a pair of laterally spaced fin members depending from said lower portion and extending rearwardly and outwardly away from each other to define an inverted V-shaped recess therebetween having downwardly and outwardly extending sides which converge forwardly and are adapted to move to an inner position in response to force being applied in a forward return stroke and to an outer position in response to force being applied in a rearward thrust stroke, and

c. resilient means restraining movement of said fin members toward said outer position in proportion to the force applied in a rearward thrust stroke so that said fin members move outwardly a decreasing angular distance in response to an increase in force applied to produce resistance to the water in proportion to the force applied.

2. A swim fin as defined in claim 1 in which said fin members are adapted to move outwardly a maximum distance of approximately l from each other in response to maximum force being applied during a thrust stroke to present a maximum surface area to the water for resistance 3. A swim fin as defined in claim 1 in which said lower portion of said support member extends transversely of the under surface of the wrist of said forearm with each fin member extending at an angle ranging from 10 to 25 away from a vertical plane passing through said support member and extending perpendicular thereto.

4. A swim fin as defined in claim 1 in which said support member and said fin members are formed integrally of a resilient material to provide said resilient means restraining movement of said fin members toward said outer position.

5. A swim fin as defined in claim 4 in which said resilient material is an elastomer having a shore durometer hardness ranging from approximately 50 to 55.

6. A swim fin as defined in claim 1 in which inwardly projecting stiffening flanges are provided adjacent the ends of said fin members.

Claims

1. A swim fin comprising, a. a strap-like support member adapted for attachment to the forearm of a user with a lower portion of said support member extending transversely of the under surface of said forearm, b. a pair of laterally spaced fin members depending from said lower portion and extending rearwardly and outwardly away from each other to define an inverted V-shaped recess therebetween having downwardly and outwardly extending sides which converge forwardly and are adapted to move to an inner position in response to force being applied in a forward return stroke and to an outer position in response to force being applied in a rearward thrust stroke, and c. resilient means restraining movement of said fin members toward said outer position in proportion to the force applied in a rearward thrust stroke so that said fin members move outwardly a decreasing angular distance in response to an increase in force applied to produce resistance to the water in proportion to the force applied.

2. A swim fin as defined in claim 1 in which said fin members are adapted to move outwardly a maximum distance of approximately 180* from each other in response to maximum force being applied during a thrust stroke to present a maximum surface area to the water for resistance

3. A swim fin as defined in claim 1 in which said lower portion of said support member extends transversely of the under surface of the wrist of said forearm with each fin member extending at an angle ranging from 10* to 25* away from a vertical plane passing through said support member and extending perpendicular thereto.

6. A swim fin as defined in claim 1 in which inwardly projecting stiffening flanges are provided adjacent the ends of said fin members. >