The present invention relates to swimming apparatus, in particular, to flippers to be worn on the feet of the swimmer to enhance mobility.
Whenever man has endeavored to develop in an environment in which he was alien, he had to look for inspiration and teaching to those organs which nature gave to the creatures native to that environment, which organs man himself lacked. For example, the ailerons of an airplane are related to the wings of the birds, and the flippers which divers and swimmers employ to supplement the fin-like structure of hands and feet are similar to the webbing and the fins of fish and batrachians (frogs, toads and the like).
It is evident that it is the movement of the water over the surface of a fin that creates the push which makes the swimmer (fish or man) proceed with increased mobility. However, this same surface creates friction, turbulence and cavitation within the water producing a diminished result in the applied force of the swimmer. Because the natural fins of man (hands or feet) are relatively small and ineffective, man has begun to utilize supplemental flippers which he fastens to his feet which enable these lower limbs to better move and flex. In general, most flippers used are formed of a single membrane or sheet having an upper and lower surface only. Recently, however, some flippers have been made utilizing a second membrane, so that a kind of a flat, hollow compartment is formed between the two membranes in the largest part of the flipper. This arrangement permits the flipper to hold back water on one side, while permitting its replacement on the other side. This flow of water resembles the flowing of water which one observes within the locomotor tubes of certain cephalopodes and molluscs, particularly the cuttlefish. As a result, a slight improvement in the effect of the applied force of the fin is observed. However, such construction does not enable the expansion or flow of water outwardly of the fins in both the downward and in the upward stroke of the swimmer, similar to that experienced by the batrachians.
One may liken this latter effect to that experienced by a bicycle rider while peddling. The propelling force of the bicycle is limited when the rider only pushes downwardly on the pedals alternately with his feet. However, by utilizing the chain drive which maintains the pedal in constant motion, the efforts of raising the opposing feet once the pedals have passed a dead center is lessened and an increased force efficiency is obtained. This is easily seen merely by fastening each foot to the pedal near the metatarsus. This method of pedalling the bicycle is similar to the push-pull work used to operate a crank.
With the foregoing in mind, the object of the present invention is to improve the construction of the flippers, used by swimmers, so that they are more effective to the swimmer in both the upward and downward strokes.
It is a further object of the present invention to provide an improved flipper which enables the flow of water through it, without creating turbulence, or cavitation, in the water.
It is another object of the present invention to provide a flipper in which greater force efficiency and a synergistic effect is obtained in both the downward and upward strokes.
The foregoing objects, together with other advantages and objects, will be apparent from the following disclosure of the present invention.