YOUTH JAVELIN

Abstract

A youth javelin having a tip, a shaft, a handle and a tail wherein the overall length of the youth javelin is in the range of 135 cm to 148 cm, the weight is in the range of 240 g and 265 g, has a balance point in the range of 57 cm and 60 cm measured from the forward end of the tip, and a weight-to-surface-area ratio in the range of 0.2000 g/cm.sup.2 to 0.2585 g/cm.sup.2.

Claims

1. A youth javelin comprising: a tip, a shaft, a handle and a tail wherein the overall length of the youth javelin is in the range of 135 cm to 148 cm, the weight of the youth javelin is in the range of 240 g and 265 g, and the youth javelin has a balance point in the range of 57 cm and 60 cm measured from the forward end of the tip.

2. The youth javelin of claim 1 wherein the weight-to-surface-area ratio of the youth javelin is in the range of 0.2000 g/cm.sup.2 to 0.2585 g/cm.sup.2.

3. The youth javelin of claim 1 wherein the tail includes a safety button.

4. The youth javelin of claim 1 wherein the tip is comprised of a soft plasticized rubber-like material suitable to protect against impalement but is resilient enough to resist permanent deformation from impacts or deformation in flight due to aerodynamic forces.

5. The youth javelin of claim 1 wherein the shaft has a measurable deflection across the longitudinal axis in a range of 15 mm to 30 mm when the shaft is supported 43.5 cm on either side of the balance point and subjected to a load perpendicular to the longitudinal axis of substantially 14 lbs at the balance point.

6. The youth javelin of claim 1 wherein the tail tapers from a maximum diameter in the range of 24 mm to 26 mm to a minimum diameter in the range of 6 mm to 10 mm over a length of 100 mm to 110 mm between the maximum diameter and the minimum diameter.

7. The youth javelin of claim 1 wherein the shaft is formed from a molded plastic extrusion having internal longitudinal ridges defining a female splined portion.

8. The youth javelin of claim 1 wherein the shaft has a diameter in the range of 24 mm to 26 mm.

9. A youth javelin comprising: a tip, a shaft, a handle and a tail wherein the overall length of the youth javelin is in the range of 135 cm to 148 cm, the weight of the youth javelin is in the range of 240 g and 265 g, the youth javelin has a balance point in the range of 57 cm and 60 cm measured from the forward end of the tip and a weight-to-surface-area ratio in the range of 0.2000 g/cm.sup.2 to 0.2585 g/cm.sup.2.

10. A youth javelin comprising: a tip, a shaft, a handle and a tail, the youth javelin having a length in the range of 135 cm to 148 cm, a weight in the range of 240 g and 265 g, a balance point in the range of 57 cm and 60 cm measured from the tip, and a weight-to-surface-area ratio in the range of 0.2000 g/cm.sup.2 to 0.2585 g/cm.sup.2, the shaft having a diameter in the range of 24 mm to 26 mm and is formed of a molded plastic extrusion having internal longitudinal ridges defining a female splined portion, the tip being formed of a soft plasticized rubber material suitable to protect against impalement but is resilient enough to resist permanent deformation from impacts or deformation in flight due to aerodynamic forces, the tail being formed of a tapered plastic plug with a male splined section to engage the shaft, and the shaft has a measurable deflection across the longitudinal axis in a range of 15 mm to 30 mm when the shaft is supported 43.5 cm on either side of the balance point and subjected to a load of substantially 14 lbs. perpendicular to the longitudinal axis substantially at the balance point.

11. A youth javelin comprising: a tip, a shaft, a handle and a tail, the youth javelin having a overall length in the range of 135 cm to 148 cm, a weight in the range of 240 g and 265 g, a balance point in the range of 57 cm and 60 cm measured from the forward end of the tip, and a weight-to-surface-area ratio in the range of 0.2000 g/cm.sup.2 to 0.2585 g/cm.sup.2 wherein when the youth javelin is thrown at an angle of inclination of substantially near 35 degrees and a release velocity substantially near 13 m/s the youth javelin will follow an optimal flight path.

12. A youth javelin comprising: a tip, a shaft, a handle and a tail, and having a weight-to-surface-area ratio in the range of 0.2000 g/cm.sup.2 to 0.2585 g/cm.sup.2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1A depicts a side view of an exemplary embodiment of a youth javelin.

[0012] FIG. 1B depicts sectional view A-A of the shaft of a youth javelin.

[0013] FIG. 2 depicts a side view of an exemplary embodiment of the tail of a youth javelin.

[0014] FIG. 3 depicts a side view of an exemplary embodiment of the tip of a youth javelin.

[0015] FIG. 4 depicts an optimal flight path for a youth javelin.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] A preferred embodiment of the youth javelin 5 is shown in FIG. 1A. The youth javelin 5 has a tip 10, a shaft 15, tail 20, and a handle 25. The balance point, 35, i.e. center of gravity, along the longitudinal axis 38 of the shaft in a preferred embodiment is located 58.8 cm from the forward end of the tip and may be in the range of 57 cm to 60 cm. A grip 25 is positioned along the shaft such that the forward end of the grip, i.e. the end towards the tip, is nominally 60 cm from the tip and may be in the range of 57 cm to 61 cm from the tip. The handle may be molded directly onto the shaft, a separate piece of molded material or similar construction placed on the shaft, or a corded grip wherein a flexible cord-like material is wrapped around the shaft. For avoidance of doubt, throughout this application, the min. and max. values cited in a range of values are included in the range.

[0017] The preferred weight of the javelin 5 is 250 g and may be in the range of 240 g and 265 g. A low weight of 250 grams allows a youth athlete more throwing repetitions before overuse injuries become an issue. In Little League baseball, where the implement weight is about 145 g, it is well known that too much throwing can be harmful. The football used in Pee Wee football leagues (age 9) weighs 270 g. By keeping the weight of a preferred embodiment as low as economically feasible, the risk of overuse injuries is reduced, and the flight characteristics are enhanced.

[0018] A preferred embodiment has an overall length of 138.5 cm and may be in the range of 135 cm and 148 cm from the forward end of the tip to the end of the tail. The diameter of the youth javelin 5 shaft 15 in a preferred embodiment is nominally 24.7 mm, but may be in the range of 24 mm and 26 mm. In a preferred embodiment, the shaft is engineered to deflect (bend) perpendicular to the longitudinal axis when a component of the force vector imparted by a thrower is not parallel, i.e. across, to the longitudinal axis. A certain level of deflection or bending of shaft 15 is desirable. In a preferred embodiment, optimal shaft deflection is measured whereby when shaft 15 is supported horizontally 43.5 cm at support points 36 and 36 on either side of balance point 35. When a load of 14 lbs is applied perpendicular to the shaft longitudinal axis 38 at the balance point 35. The preferred deflection is in a range of 15 mm to 30 mm.

[0019] In a preferred embodiment, the shaft 15 is constructed from a molded plastic extrusion having internal longitudinal ridges 16 (Ref. FIG. 1B) parallel to the longitudinal axis 38. These ridges define a female splined portion that may engage with the male splined section 22 of the tail 20 (Ref. FIG. 2.) However, other methods of molding, or fabrication from other materials, such as aluminum, carbon fiber, fiber glass, or wood may be suitable, as long as they meet the shaft deflection requirements. Further, although the internal longitudinal ridge structure may be preferred, the interior surface may be smooth or have other cross sectional shape details.

[0020] The weight-to-surface-area ratio, as measured in grams per square centimeter; of a preferred embodiment may have a weight-to-surface-area ratio of substantially 0.24 g/cm.sup.2 and may be in the range 0.2000 g/cm.sup.2 to 0.2595 g/cm.sup.2. The surface area is inclusive of the exterior surfaces of the tip 10, shaft 15, tail 20 and handle 25. When determining the surface area of the handle or grip, surface contours, such as a molded in grip enhancing textures or use of a corded grip can be ignored and the handle surface area presumed to be substantially flat for surface area calculation purposes.

[0021] Refer now to FIG. 2. A preferred embodiment of the tail 20 consists of a plastic plug that tapers in substantially a conical shape from a diameter nominally the same as the shaft diameter and varying in the same range as the shaft diameter. The tail tapers over a length L.sub.2 of approximately 100 mm to 110 mm before flaring out to an approximately 12 mm diameter by 3 mm thickness safety button 21. The purpose of the safety button element is to prevent accidental impalement. Other shapes may be incorporated in the end of tail 20, such as a substantially hemispherical form to perform the safety function. The tail 20 may have a male splined section 22 that may engages the interior longitudinal ridges 16 of shaft 15. The tail 20 may be affixed into shaft 15 by adhesive, mechanical means, press fit or thermobonding for example. Tail 20 has a maximum diameter, D.sub.3, of 24.7 mm and may range from 24 mm to 26 mm, a minimum diameter, D.sub.4, in the range of 6 mm to 10 mm at the beginning of the flare into the safety button. The tail length, L.sub.2, between the diameters D.sub.3 and D.sub.4 is in the range of 100 mm to 110 mm.

[0022] Refer now to FIG. 3 which shows an enlarged view of tip 10. A preferred embodiment of tip 10 may be made of a soft plasticized rubber-like material as another anti-impalement safety feature. The tip material is also resilient enough to resist permanent deformation as a result of repetitive impacts and temporary deformation from aerodynamic forces during flight. Illustrated is a cavity 12 for receiving shaft 15. Tip 10 may be affixed onto shaft 15 by adhesive, mechanical means, press fit or thermobonding for example. In a preferred embodiment, tip 10 has a diameter D.sub.1 at its widest point which is 32.5 mm and may range from 28 mm to 35 mm. Further, tip 10 has a diameter D.sub.2 at its forward end as the shape transitions into approximately a hemisphere. D.sub.2 is 16.75 mm and may range from 15 mm to 20 mm. The length, L.sub.3, from D.sub.1 to D.sub.2 is preferably 137.75 mm and may range from 130 mm to 142 mm.

[0023] Refer now to FIG. 4 which depicts an optimal flight path 41 for a thrown youth javelin 5. When the youth javelin 5 is thrown with a the throwing force vector commensurate with the longitudinal axis 38 (i.e., thrown through the point) at an initial angle of inclination 40 substantially near 35 degrees, as measured upwards from the horizontal plane, in no wind conditions, and at a release velocity substantially around 13 m/s, the youth javelin 5 enters an initial climbing phase 42 of the optimal flight path. During climbing phase 42, the follows a visually straight trajectory relative to the later phases when the youth javelin 5 starts to slow down. The youth javelin 5 then transitions into gliding phase 44 where the youth javelin 5 settles into a more arcing flight path with a slight nose up angle-of-attack 45 relative to the optimal flight path 41. As more speed has bleeds off the youth javelin 5 enters the turnover and landing phase 46 where it lands tip first. If the youth javelin 5 is thrown such that the balance point 35 is on the proper angle of inclination, but the longitudinal axis 38 is inclined above or below and/or left or right of the vector defined by the flight of the balance point (center of gravity) 35, unwanted additional aerodynamic drag will cause the youth javelin 5 to depart from the optimal flight path.

[0024] Selected The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms a, an and the are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms comprises and/or comprising, and includes and/or including when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[0025] The terms of degree such as substantially, about and approximately as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. For example, these terms can be construed as including a deviation of at least 5% of the modified term if this deviation would not negate the meaning of the word it modifies.

[0026] The term suitable, as used herein, means having characteristics that are sufficient to produce a desired result. Suitability for the intended purpose can be determined by one of ordinary skill in the art using only routine experimentation.

[0027] Moreover, terms that are expressed as means-plus function in the claims should include any structure that can be utilized to carry out the function of that part of the present invention. In addition, the term configured as used herein to describe a component, section or part of a device includes hardware and/or software that is constructed and/or programmed to carry out the desired function. Different aspects of the invention may be combined in any suitable way.

[0028] While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the present invention as defined in the appended claims. Furthermore, the foregoing description of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the present invention as defined by the appended claims and their equivalents. Thus, the scope of the present invention is not limited to the disclosed embodiments.