SHOCK AND VIBRATION ABSORBING SYSTEM FOR BASEBALL AND SOFTBALL BATS

Abstract

A shock and vibration absorbing system includes a shock and vibration dampener disposed within a handle or tapered section of a bat. The dampener includes at least one elastomeric dampening element for supporting a mass in suspension within the bat without the mass contacting an inner surface of the bat. The dampening elements include a body having the mass extending therethrough and a plurality of spaced apart projections having distal ends in contact with an inner surface of the bat.

Claims

1. A shock and vibration absorbing system for baseball and softball bats, comprising: a bat having a handle at a first end thereof and a barrel at a generally opposite end thereof and a tapered section intermediate the handle and barrel; and a shock and vibration dampener disposed within the handle or tapered section, the dampener including: a mass; and at least one dampening element for supporting the mass in suspension within the bat without the mass contacting an inner surface of the bat; wherein the at least one elastomeric dampening element comprises a body having the mass extending therethrough and a plurality of spaced apart projections having distal ends thereof in contact with an inner surface of the bat.

2. The system of claim 1, wherein the bat is comprised of a metal or composite material.

3. The system of claim 1, wherein the dampener is disposed within the handle between an end of the handle and the tapered section.

4. The system of claim 3, wherein the dampener is disposed within ten inches of the end of the handle.

5. The system of claim 1, wherein the mass is between 0.5 and 3.5 inches in length.

6. The system of claim 1, wherein the mass comprises a rod extending longitudinally within the bat.

7. The system of claim 1, wherein the body of the dampening element comprises a generally cylindrical disc and the projections comprise a plurality of spaced apart teeth extending radially outward from the disc.

8. The system of claim 1, wherein the mass weighs 0.5% to 10% of a total weight of the bat.

9. The system of claim 1, including a retainer disposed adjacent at least one end of the dampener for maintaining the location of the dampener within the bat.

10. A shock and vibration absorbing system for baseball and softball bats, comprising: a bat having a handle at a first end thereof and a barrel at a generally opposite end thereof and a tapered section intermediate the handle and barrel; and a shock and vibration dampener disposed within the handle or tapered section, the dampener including: an elongated mass extending longitudinally within the bat; and a plurality of elastomeric dampening elements for supporting the mass in suspension within the bat without the mass contacting an inner surface of the bat in spaced relation to one another along a length of the mass; wherein the elastomeric dampening elements comprise a body having the mass extending therethrough and a plurality of spaced apart projections having distal ends thereof in contact with an inner surface of the bat; wherein the bat is comprised of a metal or composite material; and wherein the mass weighs 0.5% to 10% of a total weight of the bat.

11. The system of claim 10, wherein the dampener is disposed within the handle between an end of the handle and the tapered section.

12. The system of claim 11, wherein the dampener is disposed within six inches of the end of the handle.

13. The system of claim 10, wherein the mass is between 0.5 and 3.5 inches in length.

14. The system of claim 10, wherein the body of the dampening element comprises a generally cylindrical disc and the projections comprise a plurality of spaced apart teeth extending radially outward from the disc.

15. The system of claim 10, including a retainer disposed adjacent to at least one end of the dampener for maintaining the location of the dampener within the bat.

16. A shock and vibration absorbing system for baseball and softball bats, comprising: a bat comprised of metal or composite material having a handle at a first end thereof and a barrel at a generally opposite end thereof and a tapered section intermediate the handle and barrel; and a shock and vibration dampener disposed within the handle, the dampener including: a mass between 0.5 and 3.5 inches in length extending longitudinally within the bat; and at least two elastomeric dampening elements spaced apart from another along a length of the mass for supporting the mass in suspension within the bat without the mass contacting an inner surface of the bat; wherein the elastomeric dampening elements comprise a generally disc-shaped body having the mass extending therethrough and a plurality of spaced apart teeth extending radially outward therefrom and having distal ends thereof in contact with an inner surface of the bat; and wherein the mass weighs 0.5% to 10% of a total weight of the bat.

17. The system of claim 16, wherein the dampener is disposed within six inches of the end of the handle.

18. The system of claim 16, including a retainer disposed adjacent to at least one end of the dampener for maintaining the location of the dampener within the bat.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings illustrate the invention. In such drawings:

[0015] FIG. 1 is an exploded perspective view of a baseball or softball bat incorporating a shock and vibration absorbing system of the present invention therein;

[0016] FIG. 2 is a partially exploded perspective view of a shock and vibration dampener embodying the present invention, with an elastomeric dampening element exploded away from the rod thereof;

[0017] FIG. 3 is a cross-sectional view of a bat incorporating the shock and vibration absorbing system of the present invention in a handle section of the bat;

[0018] FIG. 4 is an enlarged view of area 4 of FIG. 3; and

[0019] FIG. 5 is a partially fragmented bat incorporating a shock and vibration dampener embodying the present invention therein, in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] As shown in the accompanying drawings, for purposes of illustration, the present invention resides in a shock and vibration absorbing system for non-wooden baseball and softball bats, such as those comprised of metal or a composite material or combinations thereof. The present invention is particularly useful in connection with metal bats which traditionally can impart painful shockwaves and vibrations into the players' hands and arms when hitting the ball, and particularly when mishitting the ball outside of the sweet spot of the bat.

[0021] With reference now to FIG. 1, a baseball or softball bat 10 embodying the present invention is shown. The bat 10 includes a handle 12 at a first end thereof, a tapered section 14 at the boundary between the handle 12 and a barrel 16 portion of the bat 10 which is used to strike the ball. Typically, the bat 10 is generally tubular and hollow. In particular, in accordance with the present invention, the handle section 12 near an end thereof is generally tubular and hollow. As is common practice, a knob 18 is attached to the open end of the handle section 12 and an end cap 20 attached to an open end of the barrel section 16 so as to enclose the bat. The knob 18 is typically enlarged in diameter as compared to an adjacent section of the handle 12 so as to prevent the player's hand from slipping off of the bat 10 when swinging the bat.

[0022] With reference to FIGS. 1 and 3, a shock and vibration dampener 22 is disposed within the bat 10, such as in the handle section 12 and/or the tapered section 14. While the dampener 22 may be disposed in either the handle 12 or the tapered section 14, or even extending between the handle 12 and the tapered section 14, it has been found that the dampener 22 is particularly effective when placed within ten inches of the end 24 of the handle 12. Typically, however, the dampener 22 is placed within six inches of the end 24 of the handle 12 or knob 18 of the bat 10. As illustrated in FIGS. 3-5, the shock and vibration dampener 22 may be placed near the end of the handle section 12, immediately adjacent to the knob 18.

[0023] With continuing reference to FIGS. 1, 3 and 4, a retainer 26, such as a generally disc-shaped insert, such as a foam insert or the like, may be disposed adjacent to at least one end of the dampener 22 for maintaining the desired location of the dampener 22 within the bat 10. A layer of adhesive 28 may be used to maintain the retainer 26 in place. A second retainer 30 may be disposed adjacent to the opposite end of the dampener 22 to maintain the location of the dampener 22 within the bat 10, as illustrated.

[0024] With reference now to FIG. 2, the shock and vibration dampener 22 comprises a mass 32, illustrated in the form of an elongated rod, which is suspended within the bat 10, typically in the handle section 12 as described above, by at least one elastomeric dampening element 34. While the mass 32 is illustrated as an elongated rod, as this configuration is particularly convenient for insertion within the straight handle section of the bat 12, it will be understood that the geometry of the mass 32, also referred to herein as a suspension element, is secondary to its size, and particularly its weight, as will be more fully described herein. For example, the mass can comprise a solid rod, a hollow cylinder, or a solid or hollow polygon bar or the like. Typically, however, the mass is generally elongated so as to fit within the handle section 12 of the bat 10 and be in spaced relation to the inner surface of the handle due to the dampening elements 34 extending between the elongated mass 32 and the handle 12. The term rod or mass or elongated mass as used herein refers to any of these geometries, including solid rod, hollow cylinder, solid polygon bar, or hollow polygon bar, or the like.

[0025] In a particularly preferred embodiment, there are a plurality of elastomeric dampening elements 34 spaced apart from one another along a length of the mass 32. The elastomeric dampening elements serve to suspend the mass 32 within the bat 10, such as within the handle 12 or tapered section 14 of the bat 10, so as to prevent the mass or rod 32 from contacting the inner surface or wall of the bat 10. With continuing reference to FIG. 2, the dampening elements 34 include a body 36 which may be of a generally cylindrical disc configuration, as illustrated. An aperture 38 enables the mass 32 to be inserted into or through the body 36. A plurality of projections 40 extend outwardly from the body 36, such as in a radial fashion as illustrated. The projections 40 may be in the form of spaced-apart teeth having recesses 42 between adjacent projections or teeth 40. The teeth or projections preferably include an inner wall engaging outer surface 44. Thus, instead of projecting to a generally sharp point, more preferably the teeth or projections 40 terminate to a generally flat or curved face 44 which is configured to engage an inner surface of the bat 10, typically an inner wall of the handle section 12. It has been found by the inventors that having spaced apart projections or teeth 40, instead of a generally smooth and continuous outer surface, enhances the dampening effect of the dampener 22. This may be due to the ability of the projections or teeth 40 to flex and bend to a degree when shockwave and vibrational forces are applied thereto when the bat 10 strikes a ball and these forces are transmitted to the mass 32.

[0026] The dampening elements 34 are comprised of an elastomeric material, such as rubber, foam, silicone or the like. It has been found that a dampening element 34 comprised of rubber has a very good damping effect as it can attenuate or eliminate the vibration ripple completely. While a dampening element 34 comprised of a foam material may be used, it has been found that at certain positions within the bat and certain weights of the mass 32 the foam dampening element does not completely attenuate or remove the vibration ripple. However, at a proper placement within the bat and at a heavier weight of the mass 32 both the rubber and foam material can completely remove and attenuate the vibration ripples. Thus, in a particularly preferred embodiment, the dampener 22 is placed within ten inches of the end 24 of the handle section 12, and more preferably within six inches of the end 24 of the handle section 12 so as to optimize the dampening effect.

[0027] The mass 32 may be comprised of any suitable material, including metal, plastic, composite, etc. The mass 32 typically has a length between 0.5 to 3.5 inches. A metal rod may be utilized, such as illustrated herein, although the geometry of the mass 32 is a secondary consideration as to the weight of the mass 32. As mentioned above, the mass can be of different geometric shapes, such as a solid rod, a hollow cylinder, or a polygon bar which may be solid or hollow, or even other geometric shapes. The mass weighs 0.5% to 10% of the total weight of the bat, depending upon the bat type and model. The bat type and bat model will also dictate the preferred length of the mass 32, which can vary between 0.5 inches to 3.5 inches depending upon the bat model. Placement of the mass 32 and the dampener 22 within the bat can also be optimized and vary between bat types and models.

[0028] The inventors have found the key parameters of the effectiveness of the dampener 22 are the stiffness of the elastomeric dampening elements 34, damping ratio, and weight of the mass or rod 32. The impact force between the bat 10 and an object, such as a ball, will create a very wide band of frequency, and the bat will respond a high energy level on its natural frequencies, especially for lower natural frequencies. The parameters of mass ratio, damping ratio, static deflection, force frequency ratio, and natural frequency ratio may be calculated in order to calculate and optimize the stiffness factor of the elastomeric dampening elements 34 and weight or mass of the suspended element or mass 32 to most effectively attenuate and eliminate the shock and vibrations which are created when the bat 10 strikes a ball or other object.

[0029] The static deflection (u.sub.st) of the bat 10 upon striking an object, such as a ball, is calculated as follows:

[00001]$u_{\mathrm{st}}=\frac{F_0}{K},$

wherein F.sub.0 is the force of impact between the bat and the object and K is the stiffness factor of the bat handle.

[0030] The natural frequency ratio (X) is calculated as follows:

[00002]$=\frac{{}_n}{{}_n},$

wherein .sub.n is the natural frequency of the elastomeric dampening element 34 or dampener 22 and .sub.n is the natural frequency of the bat.

[0031] The force frequency ratio (r) is calculated as follows:

[00003]$r=\frac{}{{}_n},$

wherein is the force frequency and .sub.n is the natural frequency of the bat.

[0032] The mass ratio () is calculated as follows:

[00004]$=\frac{m}{M},$

wherein m is the weight or more particularly the mass of the rod or suspended element or mass 32 and M is the mass of the bat 10.

[0033] The dampening ratio () is calculated as follows:

[00005]$=\frac{c}{\sqrt[2]{\mathrm{mk}}}=\frac{c}{2.Math.m.Math..Math.{}_n},$

wherein c is the dampening coefficient of the dampener 22, k is the stiffness factor of the dampener 22, m is the mass of the suspended element, rod or mass 32, and .sub.n is the natural frequency of the dampener 22, and more particularly the suspended mass 32.

[0034] A calculation of these parameters will indicate the appropriate mass, or weight, of the suspended mass or element 32 to be used within a particular type and model of bat. As mentioned above, the weight of the suspension rod or mass 32 is from 0.5%-10% of the weight of the bat. It has been found that the weight of the suspended mass 32 is preferably approximately 1.0 ounce or greater. Weights of the suspended element or mass 32 which are much less, such as 0.2 ounce-0.6 ounce have been known to retain some ripple vibration, whereas when the suspended mass 32 weighs at least 1.0 ounce the vibration ripple can be attenuated or eliminated completely within a very short period of time, such as a fraction of a second.

[0035] Bats tested without the dampener 22 of the present invention have been found to have vibration ripples lasting greater than five seconds. However, depending upon the selected parameters and location of the dampener 22, the decay time can be between to 1/20 of this time so that the vibration ripple is completely attenuated in less than a second, and more typically in a fraction of a second. Furthermore, the dampener 22 of the present invention dampens the otherwise loud metallic ping sound of a hollow metallic bat significantly. Thus, the dampener 22 of the present invention dampens the vibrational motion of the bat at its natural frequency when forced vibration is created by the impact between the bat 10 and a ball or other object. This is done in an extremely effective manner utilizing the dampener 22 which is relatively easy to manufacture and install within the bat 10. Furthermore, the parameters of the dampener 22 and its location within the bat 10 can be adjusted depending upon the type of bat to optimize the dampening effects for each bat type 10.

[0036] With reference to FIG. 5, it will be appreciated that the length of the suspended mass 32 can vary as needed and the number of spaced-apart elastomeric dampening elements 34 increased as needed or desired. Having at least two spaced-apart elastomeric dampening elements has been found to be particularly effective, although additional elastomeric dampening elements 34 may be incorporated, such as to accommodate the length of the suspended mass 32.

[0037] Although several embodiments have been described in detail for purposes of illustration, various modifications may be made without departing from the scope and spirit of the invention. Accordingly, the invention is not to be limited, except as by the appended claims.