Patent Abstract:
The present invention relates to a ball bat with improved shock and vibration dampening. More particularly, the present invention relates to a ball bat with a handle, a barrel, and a socket assembly interposed between the handle and barrel. The socket assembly allows the barrel and handle to move relative to each other, which dampens shock and vibration.

Full Description:
BACKGROUND OF THE INVENTION 
     (a) Field of the Invention 
     The present invention relates to a ball bat with improved shock and vibration dampening. More particularly, the present invention relates to a ball bat with a handle, a barrel, and a socket assembly interposed between the handle and barrel. The socket assembly allows the barrel and handle to move relative to each other, which dampens shock and vibration. 
     (b) Description of the Prior Art 
     Baseball and softball are very popular sports in the United States, Japan, Cuba, and elsewhere. Ball bats and similar implements which impart or receive impact forces transmit the shock and vibrations of impact to the handle of the bat, causing the hands of the user to receive an uncomfortable or painful sensation. This sensation is more pronounced when the impact occurs on an area of the bat outside of the center of percussion or “sweet spot” of the bat. 
     The problem of this sensation being transferred to a user is well known in baseball. Fear of pain or discomfort may decrease the user&#39;s confidence and enthusiasm, impairing his or her performance in the sport. This problem is especially troublesome for individuals first learning the game or children. 
     Shock absorbing ball bats are known in the prior art, but each have their drawbacks. For example, a large number of parts and complex construction may make such ball bats more expensive than a conventional ball bat. For ball bats including composite materials, a complex shock absorbing system may require separate curing steps for different components of the ball bat. Other methods of producing shock absorbing ball bats may by applicable only to bats with metal barrels. Accordingly, what is needed is a simple, reliable, and cost-effective design that is effective in reducing the uncomfortable sensation produced by impact on the ball bat. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a novel design for a ball bat which decreases the shock and vibration resulting from an impact so as to minimize the discomfort of the user of the ball bat. 
     The present invention relates to a ball bat with improved shock and vibration dampening. More particularly, the present invention relates to a ball bat with a handle, a barrel, a notch, and a socket assembly adjacent to the notch and interposed between the handle and barrel. The socket assembly comprises a socket and a wedge. The inner surface of the barrel and outer surface of the handle are contoured to retain the generally toroidal socket. The socket includes a central channel sized to receive the handle. The socket allows the barrel and handle to move relative to each other, which dampens shock and vibration. 
     The wedge is located between the barrel and handle, restricting the relative movement between the handle and barrel when a ball is struck. The degree of restriction of relative movement between the handle and barrel can be varied by selecting the thickness of the wedge and the material from which the wedge is constructed. In some embodiments, the notch includes a ring disposed coaxially around the handle which acts cooperatively with the wedge to restrict the relative movement between the handle and barrel. In this embodiment, the notch may also include fill material, such that the barrel, ring, fill material, and handle, provide a substantially continuous and smooth exterior surface for the ball bat. 
     In one embodiment, the vibration dampening ball bat of the present invention comprises a barrel including a tapered end, a handle, a socket assembly interposed between the barrel and handle, the socket assembly including a socket and a wedge, whereby the barrel and handle are capable of moving relative to each other about the socket, the movement being restricted by the wedge. In this embodiment, the socket has a generally toroidal shape and includes a central channel, the wedge has a truncated generally conical shape and includes a small diameter end and a central channel, and the socket is attached to the small diameter end of the wedge, whereby the handle is serially positioned within the central channel of the socket and the central channel of the wedge. 
     In another embodiment, the vibration dampening ball bat of the present invention comprises a composite barrel including a tapered end, a composite handle, a socket assembly interposed between the barrel and handle, the socket assembly including a socket attached to a wedge, a notch located adjacent to the socket on a side opposite the wedge, and a ring positioned around the handle and located in the notch, whereby the barrel and handle are capable of moving relative to each other about the socket, the movement being cooperatively restricted by the wedge and ring. 
     In a further embodiment, the present invention comprises the method of making a vibration dampening ball bat, namely (a) providing a hollow composite barrel having a tapered end, the barrel being comprised of composite material, (b) providing a socket assembly, the socket assembly comprising a wedge having a large diameter end and a small diameter end and a socket attached to the small diameter end, (c) providing a hollow handle sized to fit within the socket assembly, (d) placing the socket assembly abut the barrel, such that the large diameter end is abut the tapered end, (e) drawing the tapered end over the socket assembly, and (f) inserting a portion of the handle into the socket assembly, whereby the barrel and handle are capable of moving relative to each other about the socket, the movement being restricted by the wedge. This embodiment may include the additional steps (g) creating a notch in the ball bat, the notch located at a longitudinal station adjacent to the socket on a side opposite the wedge, (h) positioning a ring around the handle, the ring located in the notch, whereby the ring restricts the movement between the barrel and handle in cooperation with the wedge, and (i) placing fill material in the notch, such that the barrel, ring, fill material, and handle, provide a substantially continuous and smooth exterior surface for the ball bat. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A better understanding of the present invention will be had upon reference to the following description in conjunction with the accompanying drawings, wherein: 
         FIG. 1  depicts a first embodiment of a ball bat; 
         FIG. 2A-2C  depict a knob-end view, a cross-sectional view along lines  2 - 2 , and an end-end view of a socket; 
         FIG. 3A-3C  depict a knob-end view, a cross-sectional view along lines  3 - 3 , and an end-end view of a wedge; 
         FIG. 4A-4C  depict a knob-end view, a cross-sectional view along lines  4 - 4 , and an end-end view of a socket assembly; 
         FIG. 5  depicts a cross-sectional view of the transition region of a first embodiment of a ball bat along lines  5 - 5  of  FIG. 1 ; 
         FIG. 6  depicts a second embodiment of a ball bat; and 
         FIG. 7  depicts a cross-sectional view of the transition region of a second embodiment of a ball bat along line  7 - 7  of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to  FIGS. 1-3 , a first embodiment of the ball bat  10  of the present invention is shown having an end  12 , a barrel  14  including a tapered end  16 , a transition region  18 , a handle  20 , a knob  22 , and a notch  24 . A socket assembly  26  comprising a socket  28  and a wedge  30  is interposed between the barrel  14  and handle  20 , adjacent to the notch  24 . 
     As shown in  FIGS. 2A ,  2 B,  2 C, and  5 , the socket  28  is pre-molded into a generally toroidal shape with a central channel  34  sized to snugly accept the handle  20 . In one embodiment, the socket  28  has an outer diameter of about 1.25 inches (3.18 cm), an inner diameter of about 0.87 inches (2.29 cm), and a length of about 0.55 inches (1.40 cm). The outer curve of the socket  28  is a segment of a circle with a diameter of 1.26 inches (3.20 cm). The inner curve of the socket  28  is a segment of a circle with a diameter of 0.98 inches (2.49 cm). The height of the socket varies from about 0.19 inches (4.83 mm) at the center to about 0.07 inches (1.78 mm) at the edges. In a preferred embodiment, as shown in  FIGS. 2B ,  2 C,  3 , and  5 , the socket  28  includes a notch  32 . The notch  32  has a length of about 0.1 inches (2.54 mm) and a height of about 0.04 inches (1.02 mm). The socket  28  may be made of any suitable material, such as, for example, a hard nylon. 
     The wedge  30  is pre-molded into a truncated, generally conical shape having a large diameter end  36  and a small diameter end  38 . The wedge  30  includes a central channel  42  sized to snugly accept the handle  20 . In a preferred embodiment, as shown in  FIGS. 3A ,  3 B,  3 C, and  5 , the wedge  30  includes a notch  40  located in the small diameter end  38 . The length of the wedge  30  is about 2 inches (5.08 cm). The small diameter end  38  has a diameter of about 1.1 inches (2.79 cm). The diameter of the wedge  30  remains constant for a length of 0.1 inches (2.54 mm), defining the length of the notch  40 , then increases along a curve with a radius of 0.05 inches (1.27 mm) to a diameter of 1.2 inches (3.05 cm). The diameter of the wedge  30  then increases at a 6.5 degree angle to a diameter of about 1.70 inches (4.32 cm) at the large diameter end  36 . The central channel  42  has a 1 inch (2.54 cm) diameter at the small diameter end  38 , which decreases in diameter at a 5 degree angle for a length of about 0.57 inches (1.45 cm) to a diameter of 0.9 inches (2.29 cm). The central channel  42  maintains a constant diameter of 0.9 inches (2.29 cm) for a length of about 1.08 inches (2.74 cm), then increases in diameter at a 45 degree angle for a length of about 0.35 inches (8.9 mm) to the large diameter end  36 . In this embodiment, the outer surface of the wedge  30  corresponds with the inner surface of the transition region  18  of the ball bat  10 . The wedge  30  may be made of any suitable material, such as, for example, rubber, or preferably, ethylene propylene diene monomer (“EPDM”) rubber with a hardness between 40-50 Shore A, ideally about 45 Shore A. 
     The socket assembly  26  is made by attaching the socket  28  to the small diameter end  38  of the wedge  30  such that the handle  20  may serially fit inside the central channel  34  of the socket  28  and the central channel  42  of the wedge  30 . As shown in  FIGS. 4B and 5 , the socket  28  contacts the wedge  30  such that the notch  40  of the wedge  30  is inserted within the notch  32  of the socket  28 . The wedge  30  may be secured to the socket  28  by any suitable method, such as, for example bonding with an adhesive. In a preferred embodiment, the notch  32  of the socket and notch  40  of the wedge  30  are bonded together using a cyanoacrylate adhesive. 
     The handle  20  is a mostly constant diameter hollow tube. The handle  20  may be manufactured using common manufacturing techniques. 
     For example purposes only, a composite handle  20  may be made by rolling at least one flat sheet of pre-impregnated composite fiber (“pre-preg”) around a mandrel, thereby making a tube with an outer diameter appropriately sized for a ball bat handle. In a preferred embodiment, the sheet of pre-preg comprises two layers of graphite pre-preg with fibers angled +/−15 degrees from the longitudinal with one layer orientated at a negative angle to the other layer. Two layers of pre-preg with a height of about 0.005 inches (0.127 mm) and fibers angled 90 degrees from the longitudinal are wrapped around the last 7.87 inches (20.0 cm) of the handle  20  at the end opposite the knob  22 . 
     The barrel  14  is a mostly constant diameter hollow tube with a tapered end  16 . In one embodiment, the barrel is made of composite material. The composite barrel may be manufactured using common manufacturing techniques. 
     For example purposes only, a composite barrel  14  may be manufactured by spirally rolling 24 layers of high aspect ratio parallelogram-shaped pieces of pre-preg, each layer having a height of about 0.005 inches (0.127 mm), on a rolling mandrel with the fibers oriented longitudinally, thereby making a tube with an outer diameter appropriately sized for a ball bat barrel. The parallelograms are rolled up such that each layer has a butt joint with itself and such that on one end all the layers stop at the same longitudinal station but on the other end, each layer is about one centimeter shorter than the previous layer, creating a tapered end  16 . In one embodiment, the layers are angled +/−37 degrees from the longitudinal with each layer orientated at a negative angle to the previous layer. 
     A finishing mandrel includes a constant diameter section and a tapered section. After being rolled up, the barrel  14  is transferred to the constant diameter section of the finishing mandrel. The socket assembly  26  is temporarily attached to the finishing mandrel by affixing the large diameter end  36  of the wedge  30  to the end of the tapered section of the finishing mandrel. Latex banding about one inch (2.54 cm) wide and 0.05 inches (1.27 mm) high is wrapped around the tapered end  16  of the barrel  14 . The tapered end  16  is then slowly drawn down the tapered section of the finishing mandrel, over the wedge  30  and over the socket  28 , such that the tapered end  16  stops at the same longitudinal station as the socket  28 . The latex banding is then removed and ribbons of pre-preg about 0.5 inches (1.27 cm) wide are wound around the lay-up directly above the socket assembly  26 , forming a thickness of about 20 layers of pre-preg, each layer having a height of about 0.005 inches (0.127 mm). By being formed directly over the socket assembly  26 , the inner surface of the barrel  14  is contoured to retain the socket assembly  26 , as shown in  FIG. 3 . 
     The barrel  14  is removed from the finishing mandrel and a portion of the handle  20  is inserted. The handle  20  serially contacts the socket  28  and wedge  30  of the socket assembly  26 , but does not contact the barrel  14 , as shown in  FIG. 5 . The handle  20  is retained within the socket  28  and wedge  30  by mechanical interference. In some embodiments, the handle  20  may be attached to the wedge  30 , such as, for example, by bonding with an adhesive. The barrel  14  and handle  20  are capable of moving relative to each other about the socket  28 , which dampens shock and vibration. The wedge  30  is located between the barrel  14  and handle  20 , restricting the relative movement between the handle  20  and barrel  14 . The degree of restriction of relative movement between the handle  20  and barrel  14  can be controlled by selecting the thickness of the wedge  30  and the material from which the wedge  30  is constructed. 
     The exterior surfaces of the barrel  14  and handle  20  do not provide a substantially continuous and smooth surface for the outer surface of the transition region  18 , as shown in  FIGS. 1 and 5 . Instead, a generally triangular shaped notch is formed in the transition region  18  of the ball bat  10 . The notch  24  is perpendicular to the long axis of the ball bat  10  and formed at a station whereby the notch  24  is adjacent to the socket  28 . The notch  24  has a maximum depth of about 0.25 inches (6.35 mm) adjacent to the socket  28 , with the depth of the notch  24  decreasing in the direction of the knob  22 . The notch  24  allows for greater relative movement between the handle  20  and the barrel  14 . 
     An inflatable bladder is inserted into the ball bat  10  assembly and a standard knob  22  is applied using techniques common in the industry. The bladder is inflated, expanding the barrel  14  and handle  20 . The expansion of the handle  20  causes the outer surface of the handle  20  to conform to the inner surface of the socket  28  and wedge  30 , as shown in  FIG. 5 . In particular, the handle  20  forms a concave “saddle” shape conforming to the inner surface of the socket  28  which mechanically locks the handle  20  within the barrel  14 . The assembly then is placed into a ball bat-shaped mold under pressure and heated to cure the ball bat, using standard techniques known in the art. Both the handle  20  and barrel  14  are cured at the same time, consequently only one composite cure cycle is needed for the ball bat  10 . After curing, an end  12 , such as a standard end cap, is applied using techniques common in the industry. 
     With reference to  FIGS. 6-7 , a preferred second embodiment of the ball bat  110  of the present invention is shown having a barrel  14  including a tapered end  16 , a transition region  18 , a handle  20 , and a notch  24 . A socket  28  and a wedge  30  are interposed between the barrel  14  and handle  120 , adjacent to the notch  24 . 
     This second embodiment of a ball bat  110  is constructed in a similar manner as the first embodiment of a ball bat  10 , but further includes a ring  144  coaxially placed around the handle  20 , in the notch  24 , such that the ring  144  abuts the socket  28  and the tapered end  16  of the barrel  14 . The height of the ring  144  is preferably equal to the depth of the notch  24  and the width of the ring is about 0.212 inches (5.38 mm). The ring  144  may be made of any suitable material, such as, for example, rubber, or preferably, EPDM rubber with a hardness between 40-50 Shore A, ideally about 45 Shore A. The ring  144  is preferably constructed from the same material as the wedge  30 . The ring  144  acts cooperatively with the wedge  30  to restrict the relative movement between the handle  20  and barrel  14  about the socket  28 . The degree of restriction of relative movement between the handle  20  and barrel  14  can be controlled by modifying the material from which the ring  144  is constructed. The remaining volume of the notch  24  may be filled with a fill material  146 , such as, for example, adding sufficient pre-preg to fill the remaining volume of the notch  24  before the cure cycle. In this preferred second embodiment, the notch  24  is filled by the ring  132  and fill material  146  such that the barrel  14 , ring  144 , fill material  146 , and handle  20 , provide a substantially continuous and smooth exterior surface for the transition region  18  of the ball bat  110 , as shown in  FIGS. 6 and 7 . 
     The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom for modifications can be made by those skilled in the art upon reading this disclosure and may be made without departing from the spirit of the invention and scope of the appended claims.

Technology Classification (CPC): 0