Abstract:
A hollow non-wood baseball or softball bat wherein the impact portion of the bat contains an inner barrel that is positioned by means of a (i) foam insert, (ii) tube extending from the bat&#39;s knob, or (iii) line attached to the bat&#39;s knob and end cap and extending throughout the bat such that the inner barrel does not come into contact with the inside wall of the bat when the bat is at rest yet when swung the inner barrel is allowed to move so as to amplify the rebound effect given to the ball upon impact with the bat.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/677,076, filed Jul. 30, 2012, which is incorporated herein by reference in its entirety. 
    
    
     In addition this application references the following US patents: 
     U.S. Pat. No. 5,415,398 filed June 1994 by Eggiman. 
     U.S. Pat. No. 5,511,777 filed February 1994 by McNeely. 
     U.S. Pat. No. 6,425,836 filed December 1999 by Misono et al. 
     U.S. Pat. No. 8,100,787 filed January 2010 by Smith. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is generally related to the field of baseball and softball and more specifically to a baseball or softball bat. 
     2. Description of the Related Art 
     High performance baseball and softball bats, hereinafter referred to simply as “baseball bats” or “bats”, are primarily made from aluminum alloys, composite materials, or some combination thereof. These bats are tubular (hollow inside) so as to optimize their weight and they consist of three sections: a relatively narrow handle portion for gripping, a relatively wider distal portion for hitting, and a tapered mid-section connecting the handle and hitting portions. Original aluminum bats were fabricated as a single piece in that they solely consisted of a frame with nothing occupying the space within the frame. It was found that these bats outperformed traditional wooden bats because of a “rebound” effect present in aluminum/composite bats. As the ball impacted the bat, the bat wall would absorb the energy from the impact by elastically deforming the wall at the point of impact. As the ball began to leave the bat the energy absorbed by the elastic deformation would be released by the wall returning to its original structure, in effect giving the ball an extra “push”, thus the rebound effect. Another name given to this effect is the “trampoline” effect. Manufacturers of bats found that by making the wall thinner the rebound effect would be magnified. However thinner walls also decreased the life of the bat as the wall would fatigue and no longer return to its original position; leaving dents or dings on the bat. As a result manufacturers begin to look at ways of utilizing the cavity within the hitting portion of the bat to increase the rebound effect and reduce fatigue. 
     A number of designs were introduced to take advantage of the space available in the cavity of the bat&#39;s hitting portion with the goal of strengthening the hitting portion while maintaining or improving the rebound effect. Some designs would decrease the width of the cavity so as to add an outer tubular sleeve while other designs would add tubular inserts within the cavity of the bat&#39;s hitting portion. These designs became to be known as multi-walled bats. Still other designs added composites to the outer wall or disks within the cavity to strengthen the wall while maintaining its flexing properties. These designs continued to be known as single wall bats. As this disclosure is for a bat with a novel method of utilizing a tubular insert this discussion will focus on multiwall bat disclosures. 
     Multiwall bat designs may be broken down into two groups. The first group have walls that are distinct from each other yet each wall directly and continuously adjoins adjacent walls. Although the walls may flex independently from each other the fact that they adjoin one another only allows for minor improvements to the rebound effect. The second group have walls where a gap(s) between the walls have been purposefully incorporated. The gap(s) allow for greater independent flexing of the walls with a corresponding greater improvement of the rebound effect so that the rebound effect may increase more linearly. 
     Examples of bats with multiple walls that directly abuts one another include U.S. Pat. No. 5,303,917 to Uke and U.S. Pat. No. 6,440,017 to Anderson which both discloses a bat with a sleeve over the outside of the hitting portion that directly and continuously adjoins the frame of the bat&#39;s hitting portion. Examples of bats with internal walls, referred to as inserts, includes U.S. Pat. No. 5,364,095 to Easton which discloses an internal insert bonded to the inside of the external metal tube and running the full length of the hitting portion of the bat and U.S. Pat. No. 6,425,836 to Misono et al. which discloses an internal insert with a weak boundary layer so as to encourage some amount of independent flexing. The advantage of these designs is simplicity in manufacturing. Since the walls directly and continuously adjoin each other they are less likely to separate. However this simplicity comes at a cost to performance as less energy is absorbed from the ball&#39;s impact with the bat resulting in a less than desired rebound effect. 
     Examples of bats with multiple walls that incorporate some sort of gap between the walls include U.S. Pat. No. 5,414,398 to Eggiman which discloses a bat with a tubular insert that is placed within the bat&#39;s hitting portion. The outside diameter of the insert is smaller than the inside diameter of the bat&#39;s outer shell so that there exists an annular gap between the two. The outside shell and tubular insert are therefore able to flex independently and, by so doing, together act as a leaf spring, resulting in greater bat performance. To prevent the insert from moving about within the frame it is secured by friction fit or fasteners. Another example is U.S. Pat. No. 6,612,945, also to Anderson, that contains a spiral inspired textured insert that makes contact with the bat&#39;s frame at each apex of the spiral. While the two walls are not as independent as the Eggiman patent they do act with greater independence than walls that directly and continuously adjoin one another. The spiral inspired textured insert is seated against a buttress at one end of the hitting portion and secured by the bat&#39;s end cap at the opposite end of the hitting portion. A final example is U.S. Pat. No. 8,007,381 to Watari et al. which discloses a bat with sleeve that fits over the outside of the hitting portion with an inside diameter larger than the outside diameter of the bat&#39;s frame such that a gap exists between the two. The sleeve is secured to the bat&#39;s frame by both structural elements and adhesives at both ends of the sleeve. The walls in multiwall bats that contain gaps between the walls are able to absorb more energy from an impact with a ball as they are able to flex with greater independence from each other. The increase in flexing in turn improve the bat&#39;s rebound effect and performance. 
     However all of the designs presented here are, in essence, single wall designs as the separate walls are securely connected or make contact, either continuously or at two or more points, with each other. As a result energy absorbed by the bat is transmitted to each wall at multiple points, not just the point of impact. Additionally the walls, since they are connected to each other, freely allow energy absorbed as vibrations to travel along the full length of the bat&#39;s frame and every structural element attached to the bat&#39;s frame. 
     On impact with a ball a bat absorbs energy by two means; flexing and vibrating. Energy that flexes the wall leads to improved rebound effect. In the multiwall designs presented here the walls will flex at each point they are in contact with each other. Using the Eggiman patent as an example the inner wall will flex at the two points where it is secured to the outer wall and where the ball impacts with the outer wall. Although most of the energy that flexes the inner wall will be at the point of impact some flexing energy will “bleed away” at the other two points where the inner wall is secured to the outer wall and correspondingly reduce the amount of flexing at the point of impact. When a ball impacts a bat the bat will vibrate. Although the bat will always vibrate the amount of vibrations may sometimes be felt by the batter and can lead to the batter experiencing a “stinging” sensation in their hands. Energy absorbed as vibrations adversely affects the rebound effect in two ways. First it can be easily seen that vibration energy directly subtracts from flexing energy in that the more energy absorbed by vibration the less energy is available to be absorbed for flexing. Vibrations also adversely impact the rebound effect by actively working against the wall flexing. Vibrations are an oscillatory effect creating an equal amount of movement away from a resting point. As the wall is flexed energy will have to be expended to overcome the vibrations resulting in a reduction of the energy used to flex the wall and therefore a less than optimal rebound effect. 
     The prior art designs presented herein provide for a less than optimal rebound effect by means of the multiple points of contact between the walls and the multiple points of contact allow vibrations to spread throughout the bat. 
     BRIEF SUMMARY OF THE INVENTION 
     Therefore, in view of the foregoing, it is an object of the present invention to provide a bat that incorporates walls that are not secured with each other so that each wall may fully flex independently of any adjacent wall to enhance the rebound effect and damping vibrations. It is another object of the present invention to provide a multiwall design that may be easily manufactured. 
     To meet the first object the bat of the present invention will comprise of a tubular bat frame with a narrow handle portion at one end, a larger hitting portion opposite to the handle portion, and a tapered portion between the two. The narrow handle portion is capped by what is called a knob, a wider piece that keeps the bat from sliding out of a batter&#39;s hands. The larger hitting portion is capped by what is called the end cap, a plastic or metal cap to cover the cavity of the tubular bat and prevent deformation of the end of the hitting portion of the bat if it is struck by the ball. An insert of a smaller outside diameter than the inside diameter of the hitting portion of the bat frame is positioned within the hitting portion of the bat frame. When the bat is at rest the insert does not make any contact with the bat frame. When the bat is swung the insert is deterred or prevented from moving axially within the hitting portion by any one of the embodiments to be described hereafter. Since the insert is not fastened or attached to the bat frame in any manner, when the ball makes contact with the bat, the insert is able to absorb a greater amount of the energy than inserts of prior art bats that are physically attached to the bat frame. The greater energy absorbed in turn causes a larger rebound effect. The sum total of the rebound effect of the wall of the hitting portion of the bat and the insert is greater than prior art bats resulting in a higher performance bat. The insert will also dampen vibrations by not being connected to the frame of the bat and by compressing against the wall on the side opposite of the impact. 
     The present invention satisfies the second object by eliminating manufacturing steps to create folds, crevices, buttresses, or attach fasteners. The embodiments to be described hereafter will show that a minimal number of components needed to position the insert within the hitting portion of the bat frame do not complicate the manufacturing process as some of the prior art bat disclosures such as U.S. Pat. No. 8,007,381. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The objects, features and advantages of the present invention will be apparent to one skilled in the art from reading the following detailed description in which: 
         FIG. 1  shows a sectional view through the center of a bat in accordance with one aspect of this invention. 
         FIG. 1   a  is a cross section view of the bat of  FIG. 1  hitting portion. 
         FIG. 2  shows a sectional view through the center of a bat in accordance with another aspect of this invention. 
         FIG. 2   a  is a cross section view of the bat of  FIG. 2  hitting portion. 
         FIG. 3  shows a sectional view through the center of a bat in accordance with another aspect of this invention. 
         FIG. 3   a  is a cross section view of the bat of  FIG. 3  hitting portion. 
         FIG. 4  shows a sectional view through the center of a bat in accordance with another aspect of this invention. 
         FIG. 4   a  is a cross section view of the bat of  FIG. 4  hitting portion. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. 
     Referring to  FIG. 1 , a bat  10  has a tubular aluminum frame  12  with a relatively large-diameter hitting portion  14 , an intermediate tapering portion  16 , and a relatively small-diameter handle portion  18 . 
     To provide for an improved rebound effect to better transfer of energy from the bat to a ball, the present invention provides for a tubular insert  20  to be suspended within the hitting portion  14  of the frame  12 . The insert  20  has an outer diameter less than the inner diameter of hitting portion  14 . As the outer diameter of insert  20  is less than the inner diameter of hitting portion  14 , insert  20  does not make contact with frame  12  when the bat is at rest. A uniform gap  22  exists between insert  20  and the inner wall of frame  12 . As shown in  FIG. 1  gap  22  extends uniformly around insert  20  and along the length of insert  20 . Although insert  20  does not make contact with frame  12  and is allowed to react to external forces completely independently of frame  12 . The various embodiments contained herein show how insert&#39;s  20  position within frame  12  is maintained. The free floating nature of insert  20  improves the rebound effect in two ways; working in total elastic harmony with the wall of hitting portion  14  and damping vibrations that reduce the amount of energy being absorbed elastically. 
     The first improvement provided by insert  20  to the bat&#39;s rebound effect is by combining energy it has elastically absorbed with that of the wall of hitting portion  14 . When a ball impacts a bat the kinetic energy present in the ball is transferred to the bat as the bat brings the ball to a halt. The transfer of energy from the ball to the bat is done in a very short amount of time, roughly about one thousandths of a second, and transfers a tremendous amount of energy as the ball compresses. Much of this energy is absorbed by the wall of the bat&#39;s hitting portion  14  elastically deforming. To increase the amount of energy absorbed the thickness of hitting portion  14  wall will need to be minimized. However this will result in increased rates of failure as the wall of hitting portion  14  will permanently deform. By suspending insert  20  energy that would normally permanently deform hitting portion  14  wall will be transferred to insert  20  by elastically deforming insert  20 . As the bat continues its swing and the ball begins to leave bat insert  20  begins to release the absorbed energy by rebounding back from its elastic deformation and pushing against the wall of hitting portion  14 . As the ball continues to leave the bat the wall of hitting portion  14  also begins to elastically rebound in concert with insert  20  with the combined effect causing the ball to “pop” off of the bat&#39;s hitting portion  14  rather than simply bouncing off. 
     The second improvement provided by insert  20  to the bat&#39;s rebound effect is by reducing the amount of energy absorbed by the bat as vibration energy. Vibrations adversely impact the rebound effect by actively working against the wall flexing. Vibrations are an oscillatory effect creating an equal amount of movement away from a resting point. As the wall is flexed energy will have to be expended to overcome the vibrations resulting in a reduction of the energy used to flex the wall and therefore a less than optimal rebound effect. Since insert  20  is completely suspended within the cavity of hitting portion  14  and is not connected to frame  12  it does not absorb any vibrating energy present on frame  12  from the impact with the baseball. As the wall of hitting portion  14  elastically deforms it comes into contact with insert  20 . Initially insert  20  will not elastically deform but will move against the inside of hitting portion  14  wall opposite that of the point of impact with the ball. Once insert  20  abuts and compresses against the wall of hitting portion  14  opposite of the point of impact vibrations that exist on frame  12  will be dampened resulting in more energy being stored by elastic deformation of hitting portion  14  and insert  20 . 
     The preferred embodiment of the present invention is shown in  FIG. 1 . Not only does bat  10  enhance rebound effect, it is also lightweight and easy to manufacture. Bat  10  comprises frame  12  that contains a relatively large-diameter hitting portion  14 , an intermediate tapering portion  16 , and a relatively small-diameter handle portion  18 . A knob  24  closes the opening at handle portion  18 . Foam  28  is a high density foam that is longer than insert  20  and in its resting state has a diameter greater than the diameter of insert  20 . Foam  28  is compressed and then inserted into insert  20  such that it protrudes out of both ends of insert  20  with a greater protrusion out of the end of insert  20  that is closest to cap  26 . The foam may be adhered to the frame by an adhesive. Finally cap  26  closes the opening at hitting portion  14 . At no point does insert  20  come into contact with frame  12  when the bat is at rest allowing insert  20  to freely move within the hitting portion  14  to both absorb energy by elastic deformation and to dampen vibrations by compressing against the wall of hitting portion  14  on the side opposite to the point of impact. 
     An alternative embodiment of the present invention is shown in  FIG. 2 . Bat  10  comprises frame  12  that contains a relatively large-diameter hitting portion  14 , an intermediate tapering portion  16 , and a relatively small-diameter handle portion  18 . A knob  24  closes the opening at handle portion  18 . Knob  24  contains an eyelet or other suitable fixture where line  30  is connected. Line  30  may be connected to knob  24  by a knot, adhesive, hook, or any other suitable means. Line  30  may be made of rope, wire, catgut, or of any material with a high tensile strength. Foam  32  is a high density foam that has a diameter greater than the diameter of insert  20 , is longer than insert  20 , and along its axis contains channel  34 . Foam  32  is compressed and then inserted into insert  20 . Line  30  is then passed through channel  34  and connected to rubber strap  36  on the opposing side of insert  20 . As cap  26  closes the opening at hitting portion  14  any slack in rubber strap  36  is removed. Rubber strap  36  keeps line  30  rigid so that insert  20  will not come into contact with frame  12  when the bat is at rest; allowing insert  20  to freely move within the hitting portion  14  to both absorb energy by elastic deformation and to dampen vibrations by compressing against the wall of hitting portion  14  on the side opposite to the point of impact. 
     A second alternative embodiment of the present invention is shown in  FIG. 3 . This embodiment is the same as the embodiment shown in  FIG. 2  with the exception that rubber strap  36  has been removed and line  30  passed through the length of frame  12  from knob  24  to cap  26 . As cap  26  closes the opening at hitting portion  14  any slack in line  30  is removed so that insert  20  will not come into contact with frame  12  when the bat is at rest; allowing insert  20  to freely move within the hitting portion  14  to both absorb energy by elastic deformation and to dampen vibrations by compressing against the wall of hitting portion  14  on the side opposite to the point of impact. 
     A final alternative embodiment of the present invention is shown in  FIG. 4 . This embodiment discloses bat  10  comprising of frame  12  that contains a relatively large-diameter hitting portion  14 , an intermediate tapering portion  16 , and a relatively small-diameter handle portion  18 . A knob  24  closes the opening at handle portion  18 . Tube  38  is attached to knob  24  and extends through handle portion  18 , tapering portion  16 , and through insert  20 . Foam  32  is a high density foam that has a diameter greater than the diameter of insert  20 , is longer than insert  20 , and along its axis contains channel  34 . Foam  32  is compressed and then inserted into insert  20 . Tube  38  is then passed through channel  34 . Cap  26  closes the opening at hitting portion  14 . Tube  38  positions insert  20  so that it will not come into contact with frame  12  when the bat is at rest; allowing insert  20  to freely move within the hitting portion  14  to both absorb energy by elastic deformation and to dampen vibrations by compressing against the wall of hitting portion  14  on the side opposite to the point of impact. 
     The embodiments disclosed herein are understood to be illustrative and not limiting in any sense. It is intended that the scope of the present invention is not limited by the above described embodiments but by the claims and it covers all modifications equivalent to the claims.