Swimmer Propulsion Device

Abstract

A novel and improved swimmer propulsion device of the type having a resiliently positioned fin which is adapted to oscillate and thereby develop fluid flow.

Description

This invention relates to a new and improved form of the device shown in my U.S. Pat. Nos. 3,122,759, 3,204,262, and 3,204,699.

A swimmer propulsion device of the type shown in my above mentioned United States patents operate on a fishtail-like propulsion principle. Prior to these inventions, swimmers' aids of the type adapted to be affixed to the body of the swimmer were primarily restricted to the principle of enlarging the effective area of a swimmer's hands or feet. The most common swimmer's aid relying on this increased effective area was of the type adapted to be worn at or near the feet of the swimmer in order to take advantage of the Australian crawl flutter kick commonly used by most swimmers. However, it was found that the endurance of the individual muscles used in this particular swimming stroke severely limited the effectiveness of this type device. Still, other type fin systems prior to my above mentioned inventions were found to be even less satisfactory because they created unsatisfactory oscillations of the body of the swimmer, whereby the body "wagged" rather than the fin system.

In my inventions shown U.S. Pat. Nos. 3,122,759, 3,204,262, and 3,204,699, the propulsive fin means operably connected to a leg attachment is adapted to be positioned immediately adjacent to the torso of the swimmer whereby the transverse reactions of the fin means is directed through the approximate center of gravity of the body of the swimmer and perpendicular to the propulsive reactions. Therefore, the body of the swimmer during operation of the device maintains its attitude despite the transverse forces and the objectionable oscillation of the body is substantially eliminated.

Because of the remarkable results of my prior inventions, it is useful in a wide range of swimming activities, including ordinary pleasure swimming, skin diving, life saving, and is particularly useful for long range swimming. The usefulness of this type device has resulted in a frequent transportation of the device by its users to various locations of use. However, the particular nature of the device has in the past made it rather difficult to transport without completely disassembling the device. Therefore, it is an important object of this inventon to provide a device of this type which is collapsible in part to be substantially compact and readily transportable without being completely disassembled. In accordance with this object it is important that such objectives be achieved without affecting the overall performance of the device.

Moreover, while the device of my previous inventions represents a major advance in swimmer propulsion devices, improvements which effect easier operation of the device and improved results are still very important to the user who is required to supply the power. Therefore, it is another important object of this invention to provide a device of this type having a new form of fin which results in improved performance.

As stated before, this type of swimmer propulsion device has also been found to be particularly effective for use by both lifeguards and skin divers. Lifeguards, of course, are often required during the course of a rescue to tow a person in distress and therefore, it would be particularly desirable if they could hold onto the person they are towing with both hands while at the same time advancing in a direction away from the person being towed. Skin divers and, of course, other divers often find it necessary while in the water to dive a substantial depth. Traditionally this is accomplished by the use of weights which counteract the natural buoyancy and the diver somersaults to a head down attitude to swim down. However, it would be preferable if the diver could dive feet first without the necessity of a reversal of attitude. Therefore, it is still another object of this invention to provide a swimmer propulsion device which can be adjusted during use to propel a swimmer in either a forward, or head first direction, or a reverse, or feet first direction.

A still further object of this invention is to provide a swimmer propulsion device of this type which is economical to manufacture. In this regard it has been found desirable in certain instances to provide a single integral fin element.

Another important object of this invention is to provide a swimmer propulsion device which can be adjusted by the swimmer during use to reverse the direction of the swimmer.

In accordance with these objects, the present invention is directed to a novel and improved swimmer propulsion device of the type having a resiliently positioned fin adapted to oscillate and thereby develop propelling fluid flow, a leg attachment and stabilizing wing adapted to be positioned at or about the feet of the swimmer, and a power transmitting shaft which extends from the leg attachment to the fin. The improvement includes collapsible portions for providing a readily transportable unit, reversing means to change the direction of the developed fluid flow, and a novel fin design for improving the overall performance of the device.

Other and further objects of this invention will become readily apparent from the following detailed description and the accompanying drawings. In the drawings:

FIG. 1 is a side elevation of the present invention in use by a swimmer in a kick position.

FIG. 2 is an exploded perspective view illustrating the various components of the invention.

FIG. 3 is a fragmental view illustrating components of the collapsing rear stabilizing wing.

FIG. 4 is a fragmental perspective view similar to FIG. 3 showing the stabilizing wing in a collapsed position.

FIG. 5 is a side elevation illustrating the improved fin design.

FIG. 6 is a perspective view of the invention in its collapsed form for transportation.

FIG. 7 is a top plan view of the fin illustrating the reversing means of the invention.

FIG. 8 is a fragmental side sectional view of the fin illustrating its normal position.

FIG. 9 is a fragmental side sectional view of the fin similar to FIG. 8 illustrating the reversed position of the fin.

FIG. 10 is a partial side view of the invention illustrating a modified form of the invention.

FIG. 11 is a front view of the form of the invention shown in FIG. 10.

Referring now in detail to the drawings, the swimming device 10 is a relatively light assembly generally comprised of wood and metal components, although in certain instances plastic components may be preferable. The device includes essentially three principal elements, the leg attachment element 11, which includes a stabilizing wing, the forward oscillating fin or vane element 12, and the power transmitting means or shaft element 13.

The leg attachment element, which is adapted to be secured to the lower legs of a swimmer, includes a pair of back leg boards 14 and 15, a front leg board 16, and a front leg or tail board 17 which also serves as the stabilizing wing. The leg boards extend across the shaft element 13 and outwardly from each side thereof. However, because of its stabilizing function, the leg board 17 is substantially longer than the other leg boards and in its operative position extends a greater distance from each side of the shaft. Preferably, the leg boards are wing shaped in cross-section with the forward edge of the leg board or stabilizing wing 17 positioned at a slight upward incline with respect to the axis of the shaft 13.

Bolts 18 and 19 are fixedly attached to the shaft 13 and extend upwardly therefrom. The front leg boards 16 and 17 are mounted on the shaft 13 with the bolts 18 and 19, respectively, passing upwardly therethrough. Positioned between the front and back leg boards and in parallel alignment with the axis of the shaft 13 is a spacer board 20 having a plurality of passageways 21 through which the bolts pass.

The back leg boards 14 and 15 are secured to the free ends of the bolts 18 and 19, respectively, by wing nuts 22. Mounted concentrically on each bolt is an adjustment spring member 23 which separates the spacer board and back leg board. The spring members 23 along with the wing nuts 22 allow for adjustment of the distance between the front and back leg boards and along with the leg pads 24 which are affixed to the front leg boards 16 and 17, provide for a secure but comfortable attachment to the swimmer's legs. It is important to note that the space between the ends of the front and back leg boards on each side of the shaft is relatively unrestricted which thereby permits easy mounting of the device to the swimmer and in addition permits the swimmer to easily dismount by merely spreading his legs.

As pointed out before, the tail board or stabilizing wing 17 is substantially longer than the other leg boards and therefore would generally interfere with transportation of the device. Preferably, then, the present invention includes a mounting bracket, generally designated 25, which is best seen in FIGS. 2 through 4. The mounting bracket 25 includes a center or body portion 26 which is contoured on one side 26 to fit onto the round shaft 13 and further includes leaves 27 which extend outwardly from each side of the body portion 26. The body portion 26 includes an aperture (not shown) through which the bolt 19 extends and the leaves each include a central opening 28. It should be noted that each leaf 27 is inclined with respect to the access of the shaft 13. The incline of the leaves 27 maintains the stabilizing wing in the proper inclined position during operation of the unit as described above. The stabilizing wing or tail board 17 in its improved form comprises two mirror image components 29 and 30 symmetric with the center axis of the shaft element 13. Each wing component is pivotally mounted to a leaf 27 by a bolt and wing nut connection 31, with the bolt extending through an aperture 32 in the wing component and through the central opening 28 in the leaf. It should also be noted that the front inside corner 32a of each wing component is rounded slightly to permit pivotal movement of the wing components 29 and 30 without interference with the spacer board 20. Thus, when it is desirable to transport the device as a unit, the stabilizing wing 17 is collapsed or folded as shown in FIGS. 4 and 6 with each wing component extending forward and generally parallel to but slightly inclined with respect to the axis of the shaft 13. This incline provides a convenient space between the folded wing components and the front leg board 16 for receiving the dismounted fin 12 as seen in FIG. 6.

The substantially straight shaft 13 extends forwardly of the leg attachment element 11 to a streamline wedge shaped projecting end member 35 which includes a bossed hole (not shown) therethrough. This hole extends perpendicular to the axis of the shaft 13 and includes a surrounding collar 36 at each end thereof. The fin, or vane, 12, which in the embodiment shown in FIGS. 1 through 7 comprises a pair of identical blade members 38, is pivotally mounted to the forward end of the shaft 13. A pivot rod 39 pivotally mounted in the hole of the projecting end member 35. The blade members each include a bore 39a which receives the extension of the rod 39. The bore 39a in each blade extends parallel to the forward or leading edge 40 of the blade and is adjacent thereto. Referring now to FIG. 5, this forward edge 40 is provided with a roughed portion preferably in the form of a plurality of parallel scribe marks or scratches 41 which extend substantially the length of each blade member. In the embodiment shown there are seven scribe marks or scratches 41, with one centrally positioned along the forward edge of the blade and three on each side of the center scribe mark. These scribe marks or scratches 41 are typically equally spaced and approximately one-fourth inch apart. These scratches provide an interruption in the otherwise smooth surface and trip the boundary layer from laminar to turbulent flow and thereby prevent separation of the flow or "stall." It has been found that this fin design with this roughed forward edge portion provides for a markedly improved performance, particularly at low effort swimming.

A coil spring 42 is used to center the fin 12. As stated previously, the fin 12 is positioned near the center of gravity of the swimmer's body to reduce to a minimum the waggle or other movement of the swimmer's body in response to a component of force incident to oscillatory motion of the fins. The direction of this component is transverse or lateral to the direction of motion of the swimmer through the water. Although a spring is shown as a centering device in this embodiment, other resilient components may be used. The spring is secured at one end by an S-hook 43 to the bolt 18 above the spacer board 20. The other end of the spring 42 is secured to the approximate midpoint of a cord 44 which in turn is attached at each end to one of the blade members. The blade members each include a hole 45 which extends from the top of the blade to the bottom of the blade as shown in FIG. 8. This hole 45 is spaced from the shaft 13 and receives an end of the cord 44. The position of the cord and blade connections is such that the tension of the cord prevents outward movement of the blades away from the shaft. At the same time the inner ends of the blades are not pushed against the projecting end of the shaft 13 because the pivot rod bottoms in the holes in the blades and is of the proper length to prevent this rubbing. It is important to note that the ends of the cord enter the holes 45 at the top of the blades and are secure to the bottom of the blade.

The reversing means which permits a swimmer to move in a generally reverse or feet first direction is shown in FIGS. 7 through 9. The reversing means, generally designated 50, includes a hook or other holding means 51 at the forward edge 40 positioned generally opposite the cord hole 45 but slightly outward therefrom. When reversing the blades, the blade is flipped over as shown in FIG. 9 with the cord extending across the normally top side of the blade through the holding means 51 to the spring 42.

The embodiment of the invention shown in FIGS. 10 and 11 is identical to the device previously described except for the fin element 12 and the forward portion of the shaft element 13. Therefore, those identical components will be designated by the same numeral as used previously.

In this embodiment the shaft element 13 extends forward at a slight downward incline and includes at its forward end a bifurcated fork member 55 which is secured to the shaft by rivets or other means. The upwardly extending and diverging ends 56 and 57 of the fork member 55 are positioned in approximately the same plane as the leg attachment element 11 and each include a bossed pivot hole (not shown) which extend transverse to the axis of the shaft 13. The fin element 12 in this embodiment is an integral single blade 58 which includes a pair of downwardly extending and forwardly positioned hook members 59 which are adapted to pivotally secure the blade 58 to the ends of the fork member 55. The continuous forward edge 60 of the fin 12 also provides for improved performance.

In operation, the swimmer mounts the device, preferably in shallow water, by straddling the device and inserting his lower legs between the leg boards. The swimmer then assumes the prone position as illustrated in FIG. 1 and begins the swimming stroke which is as follows: the knees are dropped in relation to the torso forcing the fin 12 downwardly in the water to the position seen in FIG. 1. The forward edge of the pivoted fin leads the rear edge during movement thereof, since the downward force exerted by the swimmer is transferred directly to the forward edge of the fin and the water lift force which acts aft of the pivot axis retards downward movement of the rear edge. This movement of the fin 12 starts the feathering or oscillating stroke. When the swimmer's legs are thereafter straightened causing the fin 12 to move upwardly, the fin will be pivoted about the rod to a position as shown in phantom lines in FIG. 1, the water lift force resisting upward movement of the rear edge of the fin. The spring 42 constantly urges the fin to the center position and aids in causing the fishtail or oscillating motion to reoccur and propel the body of the swimmer through the water. The lift force on the blades acts at about the quarter chord point aft from the leading edge. The chord is the distance from the leading edge to the trailing edge of the blade. The pivot axis is ahead of this point at about the one-eighth chord point. Thus the blade tends to "weathercock" or align itself with the direction of the relative water flow. The spring tends to resist this complete alignment process thus developing an angle of attack between the vane and the relative flow direction thus providing the lift on the blade. The blade position, direction of relative water flow, and direction of the lift force reverse each half cycle of operation resulting in a "sculling" or swimming action which provides a net forward thrust. The arms of the swimmer may be held directly in front of the head with the hands extended to aid in directing the swimmer. The hands may be manipulated to act as vanes or cause yaw or roll. The swimmer thereafter repeats the knee action stroke to cause the fishtail motion thereby propelling the body through the water.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

Claims

I claim:

1. A device for providing for propulsion to utilize a swimmer's power of the type having engaging means adapted for engagement with the lower leg portions of a swimmer, power transfer means attached to and operative with said engaging means, fin means pivotally attached to said power transfer means and positioned substantially opposite the center of gravity of the swimmer's body, and resilient means connecting said fin means to said power transfer means, wherein the improvement comprises:

at least one blade member forming said fin means and being positioned transverse of an axis at said power transfer means;

said blade member having a forward lead edge and a back trailing edge; and

means to reverse the relative positions of said lead edge and said trailing edge with respect to said engaging means.

2. A device for providing for propulsion to utilize a swimmer's power of the type having engaging means adapted for engagement with the lower leg portions of a swimmer, power transfer means attached to and operative with said engaging means, fin means pivotally attached to said power transfer means and positioned substantially opposite the center of gravity of the swimmer's body, and resilient means connecting said fin means to said power transfer means, wherein the improvement comprises:

at least one blade member forming said fin means and being positioned transverse of the axis of said power transfer means;

said blade member having a forward lead edge; and

said lead edge having a roughened portion to prevent separation of flow thereacross.

3. The device of claim 2, wherein a plurality of scribe marks extending longitudinally along said forward lead edge form said roughened portion.

4. A device for providing for propulsion to utilize a swimmer's power of the type having engaging means adapted for engagement with the lower leg portions of a swimmer, stabilizing means adapted to maintain the swimmer's body in a level attitude, power transfer means attached to and operative with said engaging means, fin means pivotally attached to said power transfer means and positioned substantially opposite the center of gravity of the swimmer's body, and resilient means connecting said fin means to said power transfer means, wherein the improvement comprises:

a pair of mirror image component members forming said stabilizing means and being positioned symmetric about said power transfer means and extending transversely thereof during operation;

connecting means connecting said component members to said power transfer means; and

said component members being collapsible about said connecting means whereby said component members can be moved to a substantially parallel position with respect to said power transfer means and thereby provide a substantially compact transportable unit.

5. The device of claim 4, wherein said fin means includes a roughened forward edge portion to prevent separation of the flow thereacross.

6. The device of claim 4, wherein reversing means are provided to hold said fin means in a reversed position and thereby effect a change in the direction of propulsion.

7. The device of claim 4, wherein said connecting means includes a mounting bracket and said component members are pivotally secured thereto.

8. The device of claim 7, wherein said mounting bracket includes a pair of leaf members extending outwardly from each side thereof, said component members being pivotally connected to said leaf members and maintained at a forward incline with respect to an axis of said power transfer means.