Abstract:
A novel swing speed training weight that is a composite plastic helical coil adapted to slidably attach to a bat used in the sport of baseball and softball.

Description:
[0001]     This application is a continuation-in-part claiming priority from U.S. patent application Ser. No. 11/337,345, filed on Jan. 23, 2006 and U.S. Provisional patent application Ser. No. 60/652,990, filed on Feb. 15, 2005. 
     
    
       [0002]     The invention disclosed and claimed herein deals with a novel swing speed training weight composed of a composite plastic helical coil having slidably frictional attachment to a baseball or softball bat.  
       BACKGROUND OF THE INVENTION  
       [0003]     Baseball and softball are sports where the player swings a sport object wherein a bat is used to hit a ball. Various training devices are utilized to achieve proficiency gains in swinging a bat. Specific sport training devices allow the player to improve their swing by enhancing both physical strength conditioning and neurological conditioning. For example, an increase in bat swing speed allows a player to hit a ball harder and further. This increased swing speed provides a competitive advantage to the player.  
         [0004]     Certain prior art describes numerous swing speed training devices to improve hitting performance. These prior art devices include custom alterations of a bat such as hollowing out sections to lighten, and/or replacement of bat materials with denser materials, thereby changing the weight of the bat.  
         [0005]     Such measures are described, for example, in U.S. Pat. No. 3,963,239 that issued on Jun. 15, 1976 to Fuji, wherein there is disclosed a hollow metallic baseball bat that is adaptable to a change in weight, center of gravity, and impact resistance. The bat contains a cylindrical handle portion which has an adjustable weight disposed within the hollow bat.  
         [0006]     U.S. Pat. No. 4,907,800, that issued on Mar. 13, 1990 to Passamaneck, et al, deals with a bat that has a fan section at its far end which provides air resistance when the bat is swung.  
         [0007]     U.S. Pat. No. 5,741,193, that issued on Apr. 21, 1998 to Nolan deals with a baseball bat that has a connectable portion on the end to provide multiple weights to the bat. The plug type weight device has a male threaded bolt that screws into a matched female threaded socket hole in the knob end of the baseball bat for use in training.  
         [0008]     U.S. Pat. No. 6,010,415, that issued Jan. 4, 2000 to Miggins, deals with a bat that has a weight ring that is attachable to the barrel of the bat and is moveable up and down the barrel of the bat to change the distance of the weight from handle of the bat.  
         [0009]     Other prior art devices include only attachments to a standard bat without alteration or damage to the bat.  
         [0010]     U.S. Pat. No. 3,608,907 that issued to Bouchard on Sep. 28, 1971 deals with a plastic coated string solder (malleable metal core) weight that is formed by spirally wrapping around the shank of a golf club. The weight is wrapped and unwrapped to be repositioned on the shank of the golf club. For applications such as baseball or softball bats, the grip strength of the string solder to the bat is not sufficient. The wrapped weight loosens and slides on the bat in hitting a ball. A quick fix is to tape the weight to hold it in place on a bat.  
         [0011]     U.S. Pat. No. 3,971,559 that issued to Diforte on Jul. 27, 1976 deals with a weighting device for attachment to a baseball bat, which device is donut-shaped having a hollow chamber adapted to be filled with a liquid or granular weighting material.  
         [0012]     U.S. Pat. No. 4,260,150 that issued to Tabet on Apr. 7, 1981 deals with a weight for a baseball bat that is slidable up and down the bat to provide a weight changing situation. The device is designed to wedge onto the bat for attachment.  
         [0013]     In U.S. Pat. No. 5,050,877, issued to Wales, on Sep. 24, 1991, there is disclosed a warm-up weight for softball bats that is an open ended cylindrical, tubular section integrally connected to a conical, tubular section, which allows for the device to wedge against the larger portion of the bat to provide a weight at that spot on the bat.  
         [0014]     There is disclosed in U.S. Pat. No. 5,395,107, issued to De Pippo, on Mar. 7, 1995, a training aid with vanes on a collar that is slidable over the large portion of the bat.  
         [0015]     U.S. Pat. No. 5,501,450 that issued to Nolan on Mar. 26, 1996 discloses a baseball bat training device that has a structure that includes a weight sized for positioning in co-axial assembly with a knob of a baseball bat. A pair of annular members is attached to the structure and they extend away from the structure in a crossed pattern with each other and are positioned in engagement with axially facing surface areas of the knob of the baseball bat.  
         [0016]     U.S. Pat. No. 5,118,102 that issued to Bahill, et al, on Jun. 2, 1992 discloses a method to determine the optimal weight size bat for a player. The method combines physical and physiological measurements of a batter&#39;s swing to determine the optimum bat weight to provide maximum departing ball speed after contact. The method uses instruments to obtain data on bat speed, plots a best fit curve to the bat speed data, determines and plots the ball speed after contact, and selects the optimum bat weight. Using the findings from the patent, one can find the optimal bat weight for a major league player to be 31.7 ounces with standard deviation of 2.38 ounces, a university player to be 27.8 ounces with a standard deviation of 2.8 ounces, and a youth league player to be 20.1 ounces with a standard deviation of 3.4 ounces. A small 2 to 4 ounce standard deviation in bat weight therefore covers the hitting performance range with each ability grouping.  
         [0017]     None of the devices of the prior art have the simplicity of the device of the instant invention.  
       THE INVENTION  
       [0018]     This invention disclosed and claimed herein deals with a novel swing speed training weight that is a composite plastic helical coil adapted to slidably attach to a bat used in the sport of baseball and softball. With more specificity, the invention is a swing speed training weight comprising a pre-formed helical coil formed by spirally cutting a composite plastic hose stock that is sized to fit onto baseball and softball bats and is adjustable about the center of gravity of the bat. A further embodiment of this invention is a helical coil composed of a composite thermoplastic utilizing two types 1) an elastic plastic component having sufficient gripping strength and 2) a viscoelastic component having sufficient impact shock absorption for hitting an actual baseball or softball. The elastic plastic has “perfect memory” material properties to provide the frictional gripping attachment of the helical coil to the bat. The viscoelastic plastic has “fading memory” material properties that maintains the attachment on the bat by absorbing the shock impact when hitting an actual baseball or softball. A round rod of more rigid elastic plastic is spirally wound and embedded during manufacture into the flexible viscoelastic plastic walls of the helical coil. The inside diameter of the helical coil is sized sufficiently smaller than the attachment location on the bat to provide the frictional grip attachment. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]      FIG. 1 ( a ) is the top view of a device of this invention.  
         [0020]      FIG. 1 ( b ) is a side view of a device of this invention with cross-sectional enlargement through line A-A of  FIG. 1 ( a ).  
         [0021]      FIG. 1 ( c ) is a cross sectional view of the spiral through line A-A of  FIG. 1 ( a ).  
         [0022]      FIG. 2 ( a ) illustrates the behavior of the elastic plastic portion of the composite  
         [0023]      FIG. 2 ( b ) illustrates the behavior of the viscoelastic plastic portion of the composite.  
         [0024]      FIG. 3  is a full side view of the various parts a bat and attachment of the device.  
         [0025]      FIG. 4 ( a ) is a full side view of a bat showing placement of the device before the center of gravity.  
         [0026]      FIG. 4 ( b ) is a full side view of a bat showing placement of the device at the center of gravity.  
         [0027]      FIG. 4 ( c ) is a full side view of a bat showing placement of the device beyond the center of gravity. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]     The speed weight training weight in this instant invention is composed of a pre-formed helical coil made from plastic materials. A composite of two plastic types being the most preferred materials. The device can be manufactured, for example, from a pre-formed composite plastic hose stock by making a continuous spiral cut centered in the flexible viscoelastic plastic wall between the spirals embedded rigid elastic plastic core. Especially preferred is a composite plastic material, for example, a class of thermosetting plastics called polyvinyl chloride (PVC) polymer. The polyvinyl chloride polymer is a well studied commercial plastic. This plastic has been formulated into basic plastic types and tailored in composite combinations to achieve enhanced material properties. The device in this invention takes advantage of the diversity of PVC plastic behaviors.  
         [0029]     A cross-section of the helical coil reveals a round rigid imbedded core of an elastic plastic composition with “perfect memory”, wherein “rigid” for purposes of this invention means more rigid than the elastic plastic, but which will bend under the same forces that bend the elastic plastic. The outer flexible walls are a viscoelastic plastic composition with “fading memory”. The viscoelastic plastic has the capability to absorb impact shock by hysteresis heat loss, for example from a bat hitting a ball. The material properties of plastic are described in more detail to achieve unique device capabilities not known in the prior art. The claimed result is a functionally efficient (simple) device for sport training.  
         [0030]     All plastics are classified as either thermosetting or thermoplastic. Thermosetting materials can only be melted once. Thermoplastics can be melted multiple times. Plastics have three basic behavior types: 1) elastic plastics, 2) viscous plastics, and 3) viscoelastic plastics.  
         [0031]     The first type; elastic plastics can be thought of as having “perfect memory”. If elastic plastics are deformed through the action of a force, they return to their original shape when the force is removed. This happens when a rubber ball bounces. The ball is deformed as it hits a hard surface but the rubber remembers its undeformed spherical shape. Rapid recovery of the shape causes the ball to bounce back.  
         [0032]     The second type; viscous (molten) plastics by contrast have “no memory”. When a force is removed, they retain their condition at the time the force is removed (or continue moving as the result of inertia). When a viscous plastic is dropped onto a hard surface, it deforms and does not bounce.  
         [0033]     The third type, viscoelastic plastics, are in between elastic plastics and viscous plastics having “fading memory”. If a force is removed shortly after it is applied, it will remember its undeformed shape and return toward it. If a viscoelastic plastic is dropped onto a hard surface, it will bounce like a ball but not as high and will be deformed for a period of time until it reforms to the original shape. This recovery time is a measure of hysteresis. However, if the force is applied for a long time, it will eventually forget its undeformed shape and not return to the original shape.  
         [0034]     A viscoelastic plastic has an elastic component and a viscous component. The viscosity of a viscoelastic plastic gives a strain rate dependent on time. A viscoelastic plastic loses energy when a load is applied, then removed. Hysteresis is observed in the stress-strain curve. Since viscosity is the resistance to plastic deformation, a viscous plastic will lose energy throughout the loading cycle. Plastic deformation results in lost energy, or the ability to absorb the shock of impact with a hard surface.  
         [0035]     More specifically, viscoelasticity in a plastic comes from a molecular rearrangement. When a stress is applied to a viscoelastic plastic, parts of the long polymer chain change position. This movement or rearrangement is called “creep”. Polymers remain a solid material even when these parts of their chains are rearranging in order to accompany the stress, and as this occurs, it creates a back stress in the material. When the back stress is the same magnitude as the applied stress, the material no longer creeps. When the original stress is taken away, the accumulated back stresses will cause the polymer to return to its original form. The material creeps, which gives the prefix visco-, and the material fully recovers, which gives the suffix-elasticity.  
         [0036]     The practical weight range for the speed weight training weight is roughly from 2% to 20% of the bat weight. For example, a 30 ounce baseball bat would have a practical weight range of ½ ounce to 6 ounces. Weights greater than ½ ounce are needed for the neural conditioning effect to achieve increased bat swing speed. Weights less than 6 ounces minimize any undesired change to a player&#39;s natural swing mechanics.  
         [0037]     The increase in swing speed is achieved by a conditioning “trick” on the player&#39;s response to a lighter weight bat when the swing speed training weight is removed. There is a small incremental speed increase in the bat swing which provides neural conditioning to develop the “fast twitch” muscle reflex. The benefits of this sport specific conditioning method are not generally known to the untrained player. Players taught by a professional batting instructor have some knowledge of this conditioning method. Without this swing speed training device, a player would need several bats of varying weights and varying weight distributions to achieve the same results. Having the luxury of a set of bats of various sizes and weights would be cost prohibitive and impractical for most young players. The benefit of using the device of this invention is that the player needs only one bat.  
         [0038]     The swing speed training weight in this invention is shown in  FIG. 1 .  FIG. 1 ( a ) is a top view of the device  1  of this invention wherein there is shown the clear plastic outer layer  2  with an imbedded, colored rigid plastic core  3 .  FIG. 1 ( b ) shows a side view of device  1  of this invention. The device  1  can be manufactured, for example, from a pre-formed composite plastic hose stock by making a continuous spiral cut  4  in the clear flexible (viscoelastic) plastic hose wall  2  centered between an imbedded spiral rigid (elastic) plastic core  3 .  
         [0039]     The enlarged cross-section in  FIG. 1 ( c ) shows an imbedded round rigid plastic coil  3  and the clear rectangular flexible plastic outer layer  2  with dimensions, for example; approximately 5/32 inch by 5/16 inch.  
         [0040]      FIG. 2  compares the behaviors of an elastic plastic and a viscoelastic plastic, wherein the vertical axis (σ) is stress and the horizontal axis (ε) is strain. Stress-Strain curves are shown for the two plastic types making up the composite plastic device  1 .  FIG. 2 ( a ) illustrates the elastic plastic used in the helical rigid plastic core.  FIG. 2 ( b ) illustrates the viscoelastic plastic used in the flexible outer layer. The darkened enclosed area in  FIG. 2 ( b ) is a hysteresis loop and shows the amount of energy lost (as heat) or absorbed in a deforming and reforming cycle. An elastic plastic shown in  FIG. 2 ( a ) does not lose energy (as heat) when a load is applied and removed.  
         [0041]     In  FIG. 1 , the rigid elastic core plastic  3  provides the gripping strength onto a bat and the outside flexible viscoelastic plastic layer  2  absorbs the impact shock from a bat hitting a ball. “Gripping strength” for purposes of this invention means retained attachment of the weight training aid to the swingable sport object when the swingable sport object is hit by a ball.  
         [0042]     Without the flexible viscoelastic outer layer  2 , the device  1  would move or fall off the bat from the impact shock of hitting a ball. The flexible viscoelastic plastic layer  2  also provides protection against breakage of the rigid elastic plastic core by absorbing the impact of an occasional direct hit of a ball on the device  1 .  
         [0043]      FIG. 3  shows a baseball bat  5  with labeled parts; handle  11 , hand grip  8 , knob  6 , transition  12 , center of gravity  7 , barrel  13  showing the “sweet spot”  9 , and distal end (large end)  10 .  
         [0044]     The on-deck version of the device  1  can be slipped over the knob  6  on the handle end  11  of a bat  5  shown in  FIG. 3 . The device  1  is positioned by placing the thumb of the right hand on the end (see downward pointing arrow) and gently pushing forward toward onto transition area  12  of the bat  5  while the left hand rotates the bat in a clockwise direction. The rotating motion on the bat opens or separates the spiral cuts  4  of device  1  and allows the device  1  to slide along the bat making for easily adjusted-to positions shown in  FIG. 4 . Once the rotating motion is stopped, the helical coil device  1  recoils to make a firm grip onto the bat  5  resulting from the embedded rigid elastic plastic core  3 . The cling friction of the flexible viscoelastic outer layer  2  both to the bat  5  and internally between the spiral cuts  4  provides the frictional lock and shock impact resistance to prevent movement on the bat  5  when hitting a ball. To adjust or remove the device  1  from the bat  5 , the bat is rotated while the device  1  is held with a hand and thumb action and pushed gently towards the desired adjustment location or to remove off the knob  6  end of the bat.  
         [0045]      FIG. 4 ( a ) shows the bat  5  with the device  1  attached before the center of gravity  7  in the transition area  12 .  FIG. 4 ( b ) shows the bat  5  with the device  1  attached over the center of gravity  7 , and  FIG. 4 ( c ) shows the device  1  attached beyond the center of gravity  7 . The position of the device  1  on the bat affects the feel of the bat. As noted Supra, the center of gravity  7  for a bat is located in the transition area  12  on the bat. The center of gravity position is a neutral (natural) feel position of a bat. The centrifugal force developed during the swing of the bat greatly magnifies the feel from small weight changes about the center of gravity  7 .  
         [0046]     A choice of plastics can be used in the manufacture of the inventive device  1 . It is contemplated within the scope of this invention to use composite plastics, for example an outside layer of flexible viscoelastic plastic and a helical rigid elastic plastic both of which are polyvinyl chloride polymer. The device  1  can be manufactured to any size diameter to accommodate standard size baseball and softball bats. What is meant by having a device inside diameter smaller than the desired location on the bat is that the device must have a slightly smaller diameter in order for the device to grip the bat. For example, a standard baseball bat has an outside diameter in the transition area  12  of about 2⅜ inches. A “smaller” inside diameter in a hitting version of the device  1  would be about 1½ inches. The smaller the inside diameter of the device  1 , the firmer the frictional attachment grip is onto the bat.  
         [0047]     A non-hitting version or “on deck” version of the instant invention for baseball and softball has an approximate 2 inch inside diameter by about 3.5 inches long that will provide a helical coil of about 3.0 ounces. It is contemplated within the scope of this invention to provide devices with preferred weight sizes of 3 and 4 ounces; however, weight sizes up to 6 ounces are practical. A device  1  with a 2 inch inside diameter slides easily on and off, over the knob  6  of a standard baseball or softball bat. This makes it convenient for the player to warm-up in the on-deck circle using the swing speed training device  1  before walking to home plate for an at-bat in a game.  
         [0048]     A sport specific training program incorporating the device  1  can be used to increase swing speed for hitting. Optimum weight amounts and locations can be used to achieve the desired training effects. A swing speed training program should start with the optimal bat weight as described in U.S. Pat. No. 5,118,102.  
         [0049]     The swing speed training devices  1  can be packaged as a kit. Kits can comprise devices  1  having a varied assortment of weights such that the individual can select a weight combination. For example, kits can contain a set of devices  1  comprising two or more devices  1 . For example, one kit containing three devices  1  may contain 2, 3, and 4 ounce devices  1  which would allow weight combinations of2, 3, 4, 5, 6, and 7 ounces on the bat, or a set of three at 1, 1.5, and 2 ounces, that would allow combinations of 1, 1.5, 2, 2.5, 3, and 3.5 ounces. Another example would be a set of four devices  1  containing 2, 3, 4, and 6 ounce devices  1  which would provide weight combinations of 2, 3, 4, 5, 6, 7, 8, 9, and 10 ounces, or a set of four devices  1  containing 1, 1.5, 2, and 3 ounces, to give weights of 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 and 5 ounces on the bat.  
       EXAMPLE  
       [0050]     A swing speed training device  1  was manufactured from a composite plastic hose stock which was razor cut between the spirally imbedded rigid plastic cores to make a helical coil having a cross section of approximately 5/32 by 5/16 inches. The hose stock was Spa-Flex® brand manufactured by Anderson Barrows, w.andersonbarrows.com. Spa-flex® hose stock is a flexible polyvinylchloride plastic that is reinforced with a round green colored rigid polyvinylchloride spiral shaped core. The Spa-Flex® hose has a brittle point of 70° F. and a maximum operating temperature of 150° F. The brittle point temperature suggests that cutting the hose stock above 70° F. would be advantageous.  
         [0051]     A swing speed training device was made from 1½ inch inside diameter Spa-Flex® hose stock for a hitting version of the training device. A 2 inch inside diameter Spa-Flex® hose stock was used to make an on-deck version of the training device for dry swings.  
         [0000]     Testing Results:  
         [0052]     The swing speed training weight was tested on wood bats as well as alloy metal and composite bats. The most demanding attachment is on a metal alloy bats. It is recommended that a player routinely re-check the attachment location after a series of 10 training swings when hitting actual balls. Should the swing weight training device  1  take a direct hit from a ball during a training swing, the device should be re-checked for attachment position.  
         [0053]     The swing speed training weight was left on the bat up to 24 hours and the recovery of the original shape occurred within the next 24 hours. A weight left on the bat longer than 1 week did not fully recover within the next week indicating permanent deformation to some degree.