US3078482A

US3078482A - Swimming accessory

Info

Publication number: US3078482A
Application number: US812214A
Authority: US
Inventors: Wyly K Crowder
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-05-11
Filing date: 1959-05-11
Publication date: 1963-02-26
Anticipated expiration: 1980-02-26

Description

Feb. 26, 1963 w. K. CROWDER 3, 8

SWIMMING ACCESSORY Filed May 11, 1959 3,078,482 SWIRIMHNG ACQESSGRY Wyiy K. Crowder, 6405 Livernois N., Troy, Mich. Filed May 11, 1959, Ser. No. 812,214 4 Qiaims. (Cl. 9-60?) The present invention relates to an improved swimming accessory for attachment to the legs of a swimmer to achieve improved utilization of leg muscles in propulsion of a swimmer through the Water.

One important object of the present invention is to provide an improved propulsion device for attachment to a swimmers legs.

Other objects of the invention are: to provide an improved device of this character whereby normal flexing of the swim-mers leg as in walking is translated into an effective forward propulsion in a direction generally longitudinally along the swimmers body; to provide a propulsion device of this character which is effective to produce a forward propulsion force on each stroke of the 'swimmers leg with a relatively high degree of efliciency; to provide an improved device of this character which is constructed in the form of a variable hydrofoil having an automatically reversible camber so that it is equal- 1y effective on both the up and the down leg strokes; to provide an improved swimming propulsion device for attachment to a swimmers leg which is efiective to create a relatively strong forward propulsive force in response to relatively easy flexing motion of the leg in a' vertical direction; and in general to provide an improved device of this character which is relatively simple and inexpensive in construction, and which is easy and comfortable to use, permitting the swimmer to propel himself with an easy, natural leg motion.

The foregoing and other objects and advantages of the invention will become apparent from the following detailed description of a preferred embodiment thereof, taken in conjunction with the drawing, wherein:

FIGURE 1 is a side elevational view of a swimmer equipped with propulsion devices according to the invention;

FIGURE 2 is a plan view of the swimmer shown in FIGURE 1;

FIGURE 3 is a sectional view of one of the propulsion devices according to the invention, the view being taken along the line 3-3 of FIGURE 2;

FIGURE 4 is a horizontal sectional view of the device shown in FIGURE 3; and,

FIGURE 5 is an enlarged view of the portion of FIG- URE 4 within the circle 4 thereof.

The muscles in the human leg are naturally highly developed for walking and running. They also adapt readily to bicycle riding. Bicycle riders use hip, knee and ankle muscles much in the same manner as they are used in walking or running. In swimming, however, the general instruction is to stiffen the knees and kick from the hips. Even with the popular webbed foot attachment, the same instruction still applies. A considerable amount of effort is required to keep the swim mers legs relatively stiff, effort which does not do any work and does not produce a forward thrust. The propulsion device of the present invention permits a swimmer to avoid the strain of keeping his legs stiff, and permits him to use his already developed walking and running muscles in their natural action to produce a forward propulsion force.

Broadly, the device of the present invention consists of a flexible hydrofoil mounted for limited angular oscillation on a supporting structure which may be strapped to the swimmers leg. The hydro-foil is spring urged toward a neutral position and is rotatably deflectable against the urging of the spring away from its neutral position in either direction, depending upon the direction of the leg movement. In its unstressed condition, the hydrofoil has no camber, but it flexes in response to water resistance to a cambered shape, with the camber in one direction during the upstroke of the leg, and in the opposite direction during the downstroke. This camher action is an important feature of the present invention since it achieves smooth acceleration of the water in the rearward direction as the water passes along the hydrofoil.

Referring now to the drawing, a set of

propulsion devices

10, 12, and 14 are illustrated therein attached to the

legs

16 and 18 of a swimmer. The

devices

10, 12, and 14 are essentially similar to each other except for differences in size. Preferably, the devices and 12, which are attached to the swimmers thighs just above the knee, are relatively large since the muscles which operate the thigh are relatively large and strong. The devices It? on the outer sides of the legs may be relatively long, and to allow adequate clearance, the devices 12 mounted on the inner sides of the legs are relatively short. The devices 14 which are attached at the ankles may be smaller than the thigh-attached

devices

10 and 12 in view of the difference in muscle strength for driving them. Since the

devices

10, 12, and 14 are all exactly similar to each other, except for differences in size, their construction and operation may be fully appreciated by a consideration of the device 14 which is shown in detail 7 in FIGS. 3, 4, and 5.

The propulsion device 14 includes a hydrofoil 20, which is made of a resiliently yieldable material such as molded rubber, and is formed in a shape generally similar to that of an airplane wing of symmetrical cross section.

When the hydrofoil 20 is in its normal, unstressed condition, its upper and lower surfaces 28 and 30 are symmetrically disposed relative to each other on opposite sides of a median plane, and the hydrofoil has no camber. The hydrofoil 20 is mounted so that it flexes autoy matically to a cambered form during use, as shown in FIG. 3. The hydrofoil 20 is fixed to a camber pitch tube 32, which extends longitudinally through the hydrofoil near its leading edge 24, and forward of its longitudinal center line. The camber pitch tube 32 is rotatable on a main pitch tube 34, which extends coaxially within the r camber pitch tube and is rigidly secured as by welding to outer and inner plates or shields 36 and 37, respectively. The outer shield 36 is rigidly secured to the outer end of an elongated torsion spring 38, which extends coaxially within the main pitch tube 34, and which is anchored at its inner end upon the support bracket 40. In this manner the wing 20 is mounted for limited angular oscillation about the axis of the torsion spring 38. The support bracket 40 may be of any desired shape to conform to the swimmers leg and may be attached thereto by an convenient means such as the straps 42, illustrated. A support tube 44 is also rigidly secured to the mount 40 and extends within the main pitch tube 34 and around the torsion spring 38 to maintain the torsion spring in proper alignment and support it against lateral deflection. A camber pitch bar 48 extends between the inner and outer shields 36 and 37, respectively, passing through the hydrofoil 2% near the trailing edge 26 thereof. The bar 48 is a slip fit within the hydrofoil 20.

In operation, the angle of incidence of the hydrofoil 2t! is determined by the resilience of the torsion spring 38 and the velocity and direction of the device through the water. The axis of support is forward of the center line of the hydrofoil 2% so that the hydrofoil tilts responsively to the force exerted upon its upper and lower surfaces 28 and 30, respectively, producing an inclined plane effect to convert the vertical leg movement into a forward thrust.

Patented Feb. 26, 1963 ported forward of its center line upon the main pitch tube/3'4 and aft of its center line upon the pitch bar 48; This construction permits the hydrofoil 20 to flex in the manner illustrated in FIGURE 3 in response to.

loading, in either direction. The camber action contributes to the efficiency of the hydrofoil 20', causing the water to be uniformly accelerated rearwardly as it passes across the hydrofoil from the leading edge 24 toward the trailing edge 26, so that the entire surface area of the hydrofoil 20 is effective to develop forward thrust. The camber action, and the streamlined shape of the hydrofoil 20 minimize drag. The device is thus efiective" to assist the swimmer to gain maximum forward thrust'with' a minimum expenditure of effort.

In use, the

devices

10, 12, and 14 are secured to the swimmerslegs, and the swimmer uses a natural leg'motion, permitting his legs to flex moderately as in walking. Excessive flexing is not desirable because of drag due to-the" legs themselves. As the legs move up and down',-.the hydrofoils tilt back and forth to adjust their angles-of incidence in accordance with the direction of leg motion, and also flex as hercinabove described inmeans supporting said hydrofoil for flexing into an arcu-' ateiiform. concave in the instantaneous direction of the driving motion.

2. A water propulsion device adapted to be worn byaswimmer comprising a flexible wing-like member, means. for mounting saidmember for oscillation about an axisgenerally parallel to and forward of a line mid- Wayibetween the leading and trailing edges of said memberand'constitutingthe soleconnection of said member tousaid swimmer, and means for restricting flexing of the trailing edge of said member relative to said means,

wherebyv surface loading of said member causes it tofi'ex into arcuate form concave toward the loading force.

3. A swimming accessory for attachment to a swimmers leg to produce a forward thrust in response to flexing of the leg comprising a flexible hydrofoil, and means for attaching said hydrofoil to a swimmers leg, said attaching means including a pivot for pivotally mounting said hydrofoil, means for fixing said pivot upon the swimmers leg in a position projecting laterally therefrom, a spring for resiliently urging said hydrofoil about said pivot toward a predetermined angular position relative to the swimmers leg, and rigid means connecting portions of said hydrofoil adjacent the leading and trailing edges thereof so that said hydrofoil flexes in response to surface loading into arcuate form concave toward the loading force.

4. A swimming accessory for attachment to a swimmers leg to produce a forward thrust in response to flexing of the leg comprising a flexible hydrofoil, and mounting means for mounting said hydrofoil upon a swimmers leg, said mounting means including an elongated torsion spring, attaching means for attaching said spring at one end thereof in fixed position upon a swimmers leg and projecting therefrom, a pivot fixed to the end of said spring opposite from said one end and extending through said hydrofoil, a pair of rigid shields mounted at opposite ends of said pivot and fixed relativethereto, means journaling said hydrofoil upon said pivot between said shields along a line forward of the center line of said: hydrofoil, and means connecting said shields to said hydrofoil adjacent to the trailing edge of said hydro foil, whereby the yieldability of said torsion spring permits tilting of said hydrofoil in adirection to rovide a forward thrust in response to a transverse leg motion and said'hydrofoil is caused by the water resistance to flex into arcuate' form concave in the direction of the leg motion thereby to accelerate the water rearwardlyi asitpasses over thevworking surface of the hydrofoil.

References @i'ted in the file off this patent UNITED' STATES PATENTS

Claims

1. A WATER PROPULSION DEVICE FOR TRANSLATING AN OSCILLATING DRIVING MOTION INTO A THRUST IN A DIRECTION GENERALLY TRANSVERSE TO THE DRIVING MOTION COMPRISING A FLEXIBLE HYDROFOIL, MEANS FOR MOUNTING SAID HYDROFOIL FOR LIMITED ANGULAR OSCILLATION ABOUT AN AXIS GENERALLY PERPENDICULAR TO BOTH THE DESIRED DIRECTION OF THRUST AND TO THE DIRECTION OF THE OSCILLATING DRIVING MOTION, AND MEANS SUPPORTING SAID HYDROFOIL FOR FLEXING INTO AN ARCUATE FORM CONCAVE IN THE INSTANTANEOUS DIRECTION OF THE DRIVING MOTION.