Undertaking
Patent
1988-06-03
1990-11-27
Crow, Stephen R.
Undertaking
A63B 6500
Patent
active
049730487
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
My present invention relates to a javelin for sporting applications, having improved flight characteristics.
BACKGROUND OF THE INVENTION
In the course of its several thousand year old history, the javelin as a weapon and later as a sports article was always made with the assumption that its streamlined shape and smoothest possible surface were essential for the best flight. This belief carried into the 20th century with the development of javelin as a sports article. One manufacturer, endeavoring to achieve the utmost in smoothness of surface, went so far as to plate the entire surface of a steel javelin with chromium. However this did not have the desired effect. This failure pointed out that other concepts also had to be taken into consideration in order to achieve the best flight properties.
Nevertheless, javelins, whose dimensions are regulated by the strict rules of the International Athletic Federation, were developed with superior airworthiness and sailing characteristics. After javelins had been thrown in excess of 100 meters, the development of this kind of sport stimulated the international federation to make changes in the regulations relating to men's javelin, and changes were also intended in women's javelin, too. The aim of the introduced changes is to reduce the flight distance and to change the trajectory of the javelin in such a way that it should always land with its tip first sticking into the ground, which results in reducing danger and eliminates debates on the appropriateness of the throw. As a matter of fact, the modifications were made with good intentions, but altered the flight characteristics of men's javelin that had outstanding airworthiness before. The javelin that is in accordance with the new regulations causes the athlete to make a throw that is, on average, 8-10 meters shorter than before. Therefore both the manufacturers and athletic competitors sought to construct a new kind of javelin that has similar properties and efficiency to that of the old one but has respect for the new rules and remains within their limitations. However, the possibility of developing an improved javelin faces firm restrictions laid down by the regulations. Men's javelin may have a weight of 800 grams, a length of 260 centimeters and a maximum diameter of 30 millimeters, while women's javelin has a required weight of 600 grams, a length of 220 centimeters and a maximum diameter of 25 millimeters. Moreover, there are rules governing the javelin's shape, center of gravity and also the location of the so-called cord that serves as a grip of the javelin. Thus, for instance, the center of gravity of men's javelin must be located under the grip at a maximum of 106 centimeters behind the front tip, while the thickness of the javelin may reach not more than 27 millimeters in the midpoint between the center of gravity and the rear tip, and the thickness has to be at least 12 millimeters at a distance of 15 centimeters from the rear tip of the javelin.
OBJECT OF THE INVENTION
Within these limitations, the object of the invention is to provide an improved sports javelin that is not contrary to the recited rule requirements, but with better flight characteristics so that, according to the ability of the competitor, increased flight distances can be achieved and, moreover, so that the javelin will have a regular land.
SUMMARY OF THE INVENTION
I have discovered that, in contradiction to the general opinion up till now, there are certain types of flight and launching velocities where the unevenness of the javelin's surface does not have a disadvantageous effect on the flight characteristics and airworthiness of the javelin, but in fact has an explicitly positive influence. Practically the theoretical explanation of this phenomenon is as follows:
A javelin, like other bodies that are launched and travel through the air, has a well-defined theoretical trajectory that depends on a given velocity (the launching velocity) and a given launching angle, assuming there is no notice taken
REFERENCES:
patent: 4333643 (1982-06-01), Saffire
patent: 4337940 (1982-05-01), Soong
"The Dynamics of Javelin Throw", A.S.M.E., Soong, Journal of Applied Mechanics, 1975, p. 1-6.
Crow Stephen R.
Dubno Herbert
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