Bat

Abstract

A baseball bat comprising a plastic hollow barrel, two end caps for closing the same, an insert in the barrel, and a tapered force fit of the insert in the barrel by virtue of a taper on the insert and a plurality of inwardly extending lengthwise directed ridges on the interior of the barrel which are tapered in height along the length of the barrel.

Parent Case Text

This application is a continuation in part of my pending application Ser. No. 189,459 filed Oct. 14, 1971 and now abandoned.

Description

BACKGROUND

This invention relates to baseball or softball bats, and more particularly, to ball bats having a nonwood body.

While the use of wooden bats has been unchallenged in Big League baseball play, their high cost, due to their tendency toward breakage, have led to dissatisfaction in other areas of play, such as in Little League play, school playgrounds, camps and the like.

However, due to tradition, there has been a reluctance to utilize more durable but less esthetically pleasing materials in bats, such as plastics. This reluctance has been crystalized by the non-wood appearance, sound, and feel of bats fabricated of plastic. Furthermore, it has been difficult to fabricate a non-wood bat that has the durability features of plastic and also approximates the performance characteristics of regulation wood bats in impact, stiffness, and sound.

SUMMARY

It is, therefore, an object of this invention to provide a baseball or softball bat made of durable materials and having the characteristics of a wooden bat.

It is a further object of the invention to fabricate a ball bat having an exterior made of a durable and easy-to-form plastic material and an interior stiffening member.

It is a more specific object of the invention to provide a ball bat having an injection molded plastic exterior and a member mounted therein for imparting the stiffness and impact characteristics of wood.

In accordance with these and other objects, a ball bat according to the invention may comprise a plastic exterior, a plurality of ribs extending from the interior of said plastic, and an elongated reinforcing member removably mounted in said plastic and supported by said ribs.

DESCRIPTION OF THE DRAWINGS

In the drawings FIG. 1 is an elevation view of the baseball bat of the invention;

FIG. 2 is a similar view broken away to show the interior parts;

FIG. 3 is an elevation view of the core insert;

FIG. 4 is an enlarged view of the butt end of the bat;

FIG. 5 is an enlarged view of the hitting end of the bat;

FIG. 6 is an exploded perspective view of the hitting end of the bat;

FIG. 7 is a cross-section view through the handle portion of the bat of FIG. 2; and

FIG. 8 is a cross-sectional view through the hitting portion of the bat of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now particularly to the drawings, the bat comprises essentially the four major elements of an exterior elongated plastic barrel 10, an insert 11, and two end caps 12 and 13. As an option a color coded ring 14 is used with the cap 13 to indicate bat size.

The barrel 10, which is contoured on the exterior into the shape of a bat for playing the game of baseball or softball, has an enlarged hitting portion 10', a smaller handle portion 10", and an intermediate portion 10"' which merges the other two portions with each other, see FIG. 2.

As shown, the barrel 10 is hollow, and is adapted to have a core 11 force fit therein. The core 11 is tapered slightly along its length and extends along essentially the whole length of barrel 10. The interior of barrel 10 has a plurality of radially inward extending ridges 15 formed thereon. Ten ridges 15 are illustrated, but it is within the scope of the invention to use more or less.

The ridges 15 extend for essentially the entire length of the barrel 10. They are tapered in their radial direction or height, see FIG. 8. That is to say, their sidewalls are tapered with respect to each other. The ridges are also tapered along their length, starting with a minimum height at the butt or cap 12 end of the bat, see FIG. 7, and gradually increasing in height to a maximum height at the hitting or cap 13 end of the bat, see FIG. 8. The dash line 15' in FIG. 2 represents the tapered height or depth of the ridges 15 as they progress along the length of the bat. The lengthwise taper to the core 11 and the lengthwise taper to the ridges 15 are matched so that when the core 11 is driven into the barrel a tapered force fit is secured between the core 11 and plurality of ridges 15.

The handle or butt end of the barrel 10 is closed by end cap 12 by virtue of threads 16 formed on the cap 12 and the corresponding outermost end of the barrel 10. The hitting end of the barrel 10 is closed by end cap 13. The ridges 15 terminate short of the outermost hitting end of the barrel to define a cavity 17 to provide a space to receive the inner end of cap 13.

Cap 13 is hollow and has a plurality of somewhat resilient inwardly extending fingers 18 formed thereon by virtue of slots 19. One of the slots 19' is longer than the others since it is intended to receive a locating ridge 20 formed in the cavity 17 to prevent the cap 13 from turning. On their interior the fingers 18 are reinforced by ridges 18', and on their exterior they have fine line ridges 18" formed thereon. The ridges 18" make it possible to drive the cap 13 into the cavity 17. As cap 13 is driven into cavity 17, the resilient fingers 18 flex slightly so that a secure connection is obtained of the cap 13 to the barrel.

A ring 14 is shown as being slipped over the fingers 18 between the outermost end of the barrel 18 and the cap 13. This ring 14 is given a color contrasting with the color of the barrel 10 according to a preselected color code to readily visually indicate the size of the bat.

The barrel 10 is injected molded, utilizing a glass filled thermoplastic resin system. The color of the thermoplastic resin is selected to approximate that of wood and the mold is designed to impart a surface design to the bat similar to the grain in a wood bat. Stain may be added later to enhance the simulated wood grain effect. The glass length utilized in the system is from 1/16 inch to 1/2inch in length with "E" or "S" glass and silane finish. The thermoplastic resin system selected is nylon 6 with a glass concentration of 20 percent "E" glass with medium length fibers of 1/4 inch and silane finish. Other thermoplastics usable are nylon 6-6, nylon 6-10, nylon 6-12 -- Polypropylene glass, styrene acrylonitrile glass, polystyrene glass, polycarbonate glass, acrylonitrile-butadienestyrene glass, polyethylene glass, polysulfone glass, polyurethane glass, polyacetal glass, polyphenylene oxide glass and polyvinyl chloride glass. In addition, the glass concentration can vary as low as 5 percent and as high as 50 percent with additives to improve weathering characteristics and glass beads to improve flow.

The butt end cap 12 is designed to be the knob end of the bat. Adhesive is applied to the threaded area 16 to make the screw fit permanent. In the alternative, the butt end cap 12 could be directly adhesively bonded or welded to the bat without utilizing the threaded connection. It may also be the terminus of the reinforcing member 11 and can be potted with adhesive to insure complete stabilization of the core. The adhesive system selected is Buna-N urethane epoxy. Other suitable adhesives are two part epoxy polyamide, epoxy polyamine, epoxy polyurethane, urethane, and any thermosetting or solvent release adhesive system with good peel and tensile shear strengths. Peel strengths of 20-50 in. lbs/in and tensile shear strengths of 2,000 to 5,000 PSI are adequate for this application. The butt end cap 12 is injected molded and is the same material as the barrel 10. The mold is designed to impart a simulated wood grain to the butt end cap 12 that matches that of the barrel 10.

The end cap 13 is a vital element of the combination in that it receives a major amount of the impact and abuse absorbed by the bat. The cap 13 is designed to provide increased resistance to impact and includes a cylindrical flange 21, see FIG. 5, which is slotted to provide the fingers 18, and which fits within the end of the barrel to provide a large surface area for adhesive bonding or welding of the end cap 13 to the barrel 10. The cap 13 is also injection molded of the same material as the barrel and a wood grain is imparted thereto. The end cap 13 can be keyed to the barrel by the slot 19' and ridge 20 to maintain the proper wood grain orientation. The ridges 18" on the bonding surface provide for an interference fit and maintain a uniform glue line thickness.

The reinforcing member 11 is used to increase the modulus of the bat in the handle area, and as a structural support in the hitting area. The impact of a ball on the barrel is transmitted through the ribs and into the reinforcing member which resists and counteracts the tendency for the bat to deform and attenuates the force of the impact. The use of the reinforcing member in combination with the ribbed barrel imparts an impact sound to the bat that approximates the sound of a wooden bat. However, if desired, sound attenuation can be achieved by the use of low density polyurethane foam in the voids between the reinforcing member, the ribs and the interior surface of the barrel.

The material makeup of the reinforcing core 11 is dictated by three variables: modulus, weight, and cost. The best material from a strength to weight ratio is a 70 percent glass 30 percent phenolic or epoxy composite which would yield using unidirectional glass cloth 1557X a modulus of 6.0 .times. 10.sup.6 PSI, but the cost of this material is prohibitive. A metallic core of aluminum (2024T3 or 7075T6) or thin walled steel could be used. Again, weight and cost would be the drawback. As a compromise between modulus, weight, and cost, a wood core of maple with a specific gravity of 0.63 gms/cc and a modulus of elasticity 1.8 .times. 10.sup.6 PSI is provided.

To assemble the bat, the barrel 10, which is formed by injection molding, is abraded inside its cavity 17 to insure adhesive bonding of the end cap 13. The maple reinforcing member is prepared with adhesive by either tape wrapping or by coating from a liquid system. The barrel is heated to about 275.degree.F., and the maple reinforcing member is inserted into the ribs or ridges 15 as by an air ram. The taper of the reinforcing member 11 and of the ribs or ridges 15 provide an interference fit of the reinforcing member with the barrel. And, the heat from the barrel causes the adhesive on the maple reinforcing member to flow uniformly and firmly join the reinforcing member to the ribs or ridges 15 of the barrel.

The end caps, which are also injection molded, are sandblasted to break the surface glaze imparted by the injection molding operation and prepared with adhesive. The adhesive is applied to the end caps when they are at a temperature of 150.degree. - 180.degree.F. The butt end cap 12 is screwed on to the barrel and the end cap 13 is forced into the barrel cavity 17 by an air ram or the like. The bat is heated to 250.degree. - 275.degree.F. for a period of 30-45 minutes to cure the adhesive.

Since the moisture was driven out of the nylon 6 thermoplastic resin by the heat generated during the molding process, moisture is restored to the bat barrel by emplacing it in a boiling water bath for about 24 hours. The moisture reduces the crystallinity of the nylon to an amorphous state, which eliminates brittleness. The bat is then spray stained to obtain the wood grain effect and then waxed to a semi-gloss finish.

Claims

I claim:

1. A fabricated baseball bat comprising a hollow elongated exterior member having the outer contour of a conventional baseball bat comprising a hitting portion, a handle portion, and an intermediate portion interconnecting the two other portions, the hitting portion having a substantially constant outer diameter, the handle portion having an outer diameter substantially smaller than that of the hitting portion, and the intermediate portion having a tapered outer diameter merging at opposite ends thereof with the hitting and handle portions, an elongated tapered reinforcing member inside said hollow elongated member, the large end of said tapered reinforcing member corresponding to said hitting portion and the small end thereof to said handle portion, a plurality of radially inward extending ribs on the inside of said hollow elongated member and spaced circumferentially about the inside surface of said hollow member, said ribs extending continuously and substantially the whole length of said hollow elongated member and being tapered from a small height at said handle portion to a maximum height at said hitting portion, said reinforcing member comprising a solid wood insert having a tapered force fit against said plurality of ribs and being substantially coextensive in length with said ribs, said hitting, handle and intermediate portions and said ribs being integral with each other and comprising glass-filled resin material, a pair of end caps closing opposite ends of said hollow elongated member, said wood insert extending along the length of said hollow elongated member from adjacent one end cap to adjacent the other end cap, and said fabricated baseball bat comprising essentially said four parts of said hollow elongated member, said insert, and said pair of end caps.

2. In a baseball bat as in claim 1, wherein said resin material comprises nylon, said wood insert comprises maple, said end caps being constructed of the same material as said hollow elongated member, and a ring on the outer end of said bat between the hitting portion and end cap therefor, said ring and hitting portion end cap having outer diameters corresponding to the outer diameter of said hitting portion, and said ring having a color contrasting with the color of said hollow elongated member to visually indicate the size of said bat in accordance with a preselected color code.