CN1325135C - Ball stick made of reinforced wood - Google Patents

Abstract

A reinforced wood bat has the same outside dimension with the conventional standard-size wooden bat, which contains a wooden core including a handle and a stick, and the two parts are formed into a slight piece having the outside dimension smaller than the standard-size wooden bat; and one or more continuous layer of registrated fabric sleeves which substantially cover the whole outer face of the wooden core and the knitted sleeve is impregnated with resin which combines, laminates, and hardens the reinforcing layer on the outer surface of the wooden core, thereby, the outside dimension of the completed reinforced bat is the same as that of the conventional standard-size wooden bat.

Description

Reinforced wooden bat

technical field

This invention relates generally to wooden bats having reinforced outer surfaces for hitting baseballs, softballs, or the like, and methods of making the same, and more particularly to solid wooden bats and methods of making solid wooden bats, which The outer surface of the bat from the sole to the top or outer end is reinforced with a composite cover comprising high strength fibers and resin laminated to the outer surface of a wood core. The fibers that reinforce the body of the bat form a diagonal mesh, and the fibers in the handle are closer to the length of the bat.

Background technique

Baseball and softball bats have been made of wood since baseball games and leagues began to be organized. Wooden bats are lathe machined to standard external dimensions and standard weights. In addition, hollow aluminum bats have emerged, favored by many young athletes, and certain regulations in certain leagues and age groups require the use of hollow aluminum bats. In addition, hollow plastic bats have also appeared, and players in younger age groups use hollow plastic bats in practice and training. Hollow plastic bats are usually used for lighter hollow plastic balls, rubber balls, etc.

美国专利Nos.1,499,128；1,611,858；3,116,926；3,727,295；3,779,551；3,811,596；3,861,682；3,955,816；3,963,239；4,241,919；4,744,136；4,763,899；4,844,460；5,114,144和加拿大专利No.962291公开了各种球棒。

The main disadvantage of solid wood bats is that they are more expensive and tend to break during use. Therefore, efforts have been made over the years to develop a reinforced wooden bat that has the weight, size, strength, rigidity, and flexibility to meet high-quality requirements within the allowable weight and size parameters, but has a long service life. Yet longer than a standard solid wood bat or extruded aluminum bat. For example, a qualifying wooden bat must be no larger than 2.75 inches in diameter.

An example of such an effort is seen in US Patent No. 3,129,003 to Wheeler et al., in which a fiberglass sleeve is fitted over the handle portion of a wooden bat, and a plastic coating on the sleeve is then used to secure the sleeve. In U.S. Patent No. 5,114,144 to Baum, a bat-shaped inner core of foamed plastic or extruded aluminum is covered with layers of resin-impregnated high-strength fiber knitted or woven cloth. It is then covered with a resin-coated veneer, and the composite is placed in a mold consisting of two mold halves, which close to allow the resin to cure, creating a bat. US Patent No. 3,598,410 to Costopoulos discloses a wood bat comprising a plurality of sheets of high strength multifiber filaments helically wound in surface grooves. Finally, US Patent No. 5,301,940 to Seki discloses a resin infusion process for attaching a continuous strand of reinforcing fiber and molding material to the outer surface of a bat core made of fusible material or foamed resin.

However, none of the prior patents disclose a reinforced wood bat having the features of the present invention. Rather, the prior art has not disclosed a reinforced solid wood bat which has a continuous cover made of high strength fibers bonded to its entire outer surface with resin. Furthermore, the prior art does not disclose a structure in which at least two layers of a braided sheath cover the entire outer surface of a solid wood core. Furthermore, the prior art does not disclose a structure in which a composite high-strength sleeve is bonded to the surface of a wood core of slightly reduced size, the size of the sleeve being equal to the reduced size of the wood core, This results in a wooden bat that is the same size as a standard wooden bat.

Contents of the invention

In accordance with the present invention, a solid wood core of reduced size is prepared which is the same shape as a wood bat and slightly smaller than the standard size of a conventional wood bat. The wood core is cut on a lathe with the short shaft support on it. The wood core is then covered with a continuous one or more layers of a conformable fabric cover made of high strength filaments, preferably a fiberglass braided cover, thereby forming a preformed bat assembly. Each layer of fabric cover is tightly sleeved on the entire outer surface of the wood core when forming a preformed bat, and the fiber filaments are arranged in the longitudinal direction at the handle portion of the bat, thereby greatly increasing the strength of the braid. A suitable curable resin, preferably an epoxy resin that cures automatically at or near room temperature, is then added to the layers of the high-strength fiber cover of the preformed bat assembly, and the resin cures to bond the cover layers Pressed and bonded to this wood core to create a bat that is the same size as a standard bat.

In a preferred embodiment of the invention, the diameter of the fiberglass braided or other conformable fabric sleeve remains constant throughout its length. The constant inner diameter of the cover is slightly smaller than the diameter of the wood plug body, far greater than the diameter of the wood core handle. The diameter of the cover can be enlarged by radial force and reduced by longitudinal force or twist. Preferably, the filaments of the sleeve form an angle of about +45°/-45° with their longitudinal axis.

Therefore, when a layer of sleeve is put on the wood core, the sleeve is slightly stretched in the shaft portion, so that the angle between the filaments and the longitudinal axis is greater than +45°/-45°. At the same time, when each cover layer is placed on the outer peripheral surface of the wood core, the core can be twisted or rotated relative to the cover, so that the cover is pulled longitudinally, and this twist makes the cover shrink, thereby tightly wrapping the bat outer or top end. Likewise, the fibers of the handle portion are tensioned or twisted so that the cover tightly wraps around the handle portion of the bat. Importantly, this tensioning and contraction of a braided sheath over the wooden core handle changes the direction of the filaments on the handle. In fact, we have found that when a braided cover is used, the direction of the fabric filaments in the handle portion becomes closer to the longitudinal axis of the bat and interlock together so that the tensile strength of the braided cover on the longitudinal axis of the handle Greatly improved, and the strength of the bat was the weakest at the handle. When laminated and bonded to the wood core with a curable resin, the filaments are molded into the bat in this favorable orientation. This structure greatly increases the strength of the bat.

The present invention also includes a unique method of manufacturing the novel bat described above. Generally, the method begins by forming a core of a solid molded bat from a standard bat stock using known bat making equipment such as a lathe. However, for purposes of the present invention, the entire outer surface of the core is turned to dimensions slightly smaller than a standard wooden bat for the fiberglass cover layer to be placed thereover. In addition, the wooden core is left with a stub shaft supported on a lathe.

The handle portion is then cut with longitudinal grooves symmetrically distributed over the circumference of the core for the application of the curable resin according to the invention. Preferably, the wood core is treated to remove the air from the wood and a resin primer is applied to the surface of the wood core. A hollow sleeve is then used to place the continuous one or more layers of braided fiberglass sleeve over the wood core to form a preformed bat assembly. It is best to have two layers of fiberglass sleeves over the wood core. For this purpose, according to the invention, the sleeve is placed on the outer surface of the sleeve, one end of the sleeve being sealed on the opening of the sleeve.

The handle end of the core is pushed into the open end of the sleeve so that the handle end of the core rests against the seal to pull the braided sleeve over the core from the outer surface of the sleeve. The cover is thus tensioned longitudinally when being placed over the handle portion of the wooden core, so that the braid stretches and fits tightly over the handle portion. When the core is fully inserted into the sleeve, the core is turned using the support stub at the shaft end as a handle. This turning action forces the sleeve to tighten over the outer end of the core to wrap around the annular bottom surface of the stub where it meets the shaft end of the bat.

Because the cover tightly wraps the outer end of the wooden core, the wooden core can be pulled out from the casing, and the cover on the wooden core will not loosen or fall off when being pulled out, and the second layer of fiberglass cover is put on the first layer simultaneously. The end of the second ply past the knob is then stretched so that the second ply tightens around the handle portion of the wood core and the first ply. At this point the preformed bat assembly is ready for further processing.

In accordance with the present invention, a preferred molding process utilizes heat shrinking to fit a known high shrinkage plastic tube over a preformed bat assembly. The shrink tubing is then used as a mold to laminate and bond the fiberglass sleeve to the wood core with a curable resin. The tube is also preferably shrunk together with a suitable tubular extension at the rod end, which serves as a vessel to receive and hold the resin, from where it is slowly flowed into the tubular mold, wetting out the fiberglass sleeve before curing of each layer. Since the handle portion of the bat is not the same diameter as the shaft portion, this method of shrinking and fitting the plastic molded tube over the preformed bat assembly requires not only heating and shrinking the plastic molded tube in a heat shrinking process, but also requiring Simultaneously stretch the plastic molded tube. This simultaneous stretching is necessary in order for the molded tube to shrink over the handle portion of the preformed barrel assembly.

Curable resin is then slowly fed into the tubular mold, preferably from the constricted tube extension, so as to wet out the layers of the fiberglass jacket. In addition, it is preferable to insert an ash wood strip in the resin of the pipe extension as a heat sink. Air pressure is also preferably used to allow the resin to wet out the fiberglass cover layers of the preformed bat assembly for the appropriate time.

After wetting the layers of the fiberglass sleeve, the preformed bat assembly in the plastic molded tube can be held upside down with a clamp to hold the bat under the knob. This allows the uncured resin and fiberglass to better fill the handle/knob interface. Once the resin has cured, remove the plastic tubular mold or heat shrink casing. The exposed bat end is then ground after cutting off the supporting stub. The handle is then sandblasted to make the handle appear rough.

It is therefore an object of the present invention to provide a reinforced wooden bat for hitting a baseball, softball, or the like, which is formed of a wooden bat having the same shape as an ordinary wooden bat but having outer dimensions slightly smaller than the standard outer dimensions of an ordinary wooden bat. Consisting of a wood core and a reinforced composite laminate made of high strength fibers bonded to substantially the entire outer surface of the wood core so that the outer dimensions of the resulting bat are comparable to those of standard wood bats same.

Another object of the present invention is to provide a reinforced wood bat as described above, wherein the reinforced composite laminate is a continuous, uninterrupted one or more layers of fabric cover, the cover is made of high strength fiber These filaments are impregnated with a curable transparent resin that works with the wood core to create a bat that looks and hits like a regular wooden bat, but is less prone to breakage and damage when hitting a baseball. Wooden bat. In fact, the bat of the present invention never broke in actual testing.

Another object of the present invention is to provide a reinforced wood bat as described above, wherein at least two continuous, uninterrupted layers of reinforced braided cover made of fiberglass filaments are bonded to substantially the entirety of the wood core. on the outside.

Another object of the present invention is to provide a reinforced wood bat according to the above objects, wherein the high-strength glass fiber filaments are at an angle of 0° to the longitudinal axis of the bat in the handle portion and in the shaft portion of the bat. It is about +45°/-45° diagonal net shape, so that the impact resistance of the shaft part is improved, and the fracture resistance of the handle part is improved.

Another object of the present invention is to provide a reinforced wood bat according to the above objects, wherein the stub shaft for supporting on the lathe facilitates the bonding and orientation of the fiberglass strands on the wood core and Helps strengthen the lamination and bonding of composite laminates to the wood core.

Another object of the present invention is to provide a reinforced wooden bat according to the above object, wherein longitudinally extending grooves are cut out symmetrically distributed on the circumferential surface of the handle portion of the bat to improve the strength of the reinforced composite laminate. Adhesion on wood core.

Another object of the present invention is to provide a method of manufacturing reinforced bats, wherein a continuous one or more layers of fiberglass cover is placed over the entire wooden core after making a bat-shaped wooden core with a smaller external dimension, A preformed bat assembly is thereby created. The preformed bat assembly is then placed into a mold, curable resin is fed into the layers of the fiberglass sleeve, and after the resin cures, the fiberglass layers are bonded and laminated to the outer surface of the wood core to create an outer dimension and An ordinary wooden bat is exactly the same as a reinforced wooden bat.

Another object of the present invention is to provide a method of manufacturing a reinforced wood bat using a preformed bat assembly wherein the wood core is manufactured by known methods including lathe support shorts projecting longitudinally on both ends of the wood core. Shaft, then sleeved, and twisting the wood core using the support stub as a handle, thereby tightening at least two layers of fiberglass braided sleeves over nearly the entire outer surface of the wood core. The fiberglass cover is then impregnated with a curable resin, which is then cured to laminate and firmly bond the reinforced cover to the wood core to create a one-piece bat.

Another object of the present invention is to provide a method of manufacturing reinforced bats in which a preform consisting of a bat core and glass fibers on its surface is formed using high heat shrinkable tubing as follows: Mold for bat components: Stretch and heat-shrink the high-shrinkage plastic tube so that the high-shrinkage plastic tube fits tightly on the pre-formed bat component to create a plastic tube mold, and at the same time, form a hollow tube elongated The tube extension is used to feed curable resin into the tubular mold and to apply air pressure to wet the glass fibers with the resin before curing.

Another object of the present invention is to provide a method of manufacturing a reinforced ball bat according to the above object, wherein, after the epoxy resin is injected into the plastic pipe mold, a heat absorber is inserted in the hollow pipe extension thereof to reduce the heat loss. The exothermic reaction of the slow epoxy resin allows sufficient time for the resin to wet out the glass fibers of the preformed bat component before curing.

Another object of the present invention is to provide a method of manufacturing a reinforced ball bat according to the above object, wherein the plastic tubular mold containing the preformed ball bat assembly whose glass fibers are wetted with epoxy resin is inverted and clamped Clamping, the clamp holds the bat just below the knob to force the uncured resin and fiberglass to better fill the handle/knob interface.

A final purpose is to provide multiple annular grooves in the shaft to increase the amount of resin in the shaft end of the bat and extend the life of the bat. These grooves may have transverse transitions or curved sides on the inside and outside.

To achieve the above objects, according to one aspect of the present invention, there is provided a reinforced wooden bat having the same external dimensions as a standard-sized wooden bat, the bat comprising: a wooden core including a handle part and a shaft part, these two parts form an elongated member, the outer dimension of this elongated part is slightly smaller than the outer dimension of standard-sized wood ball bat; The curable resin is impregnated and laminated to the majority of the outer surface of the core, the thickness of the layer or layers increasing the outer dimensions of the core such that the final dimensions of the reinforced bat are in line with the standard Dimensions The outer dimensions of the wooden bat are the same, and the handle portion of the wood core includes a plurality of longitudinally extending grooves symmetrically spaced on the handle portion of the bat.

According to another aspect of the present invention, there is provided a reinforced wood bat having the same external dimensions as a standard size wooden bat, the bat comprising: a wood core including a handle portion and a shaft part, the two parts form an elongated piece of wood, the outer dimensions of which are slightly smaller than those of a standard-sized wooden bat; The sleeve is mostly made of fiberglass and is impregnated with a curable resin and laminated to cover almost the entire outer surface of said wood core, the thickness of said layer or layers increasing the outer dimensions of the wood core so that the The final dimensions of the reinforced bat are the same as the outer dimensions of said standard size wooden bat, said cover comprising two continuous layers, each covering substantially the entire outer surface of the wood core, said two successive layers also being continuous with each other , and the outer layer is reversely stacked on the inner layer.

According to yet another aspect of the present invention, there is provided a reinforced wood bat having the same external dimensions as a standard size wooden bat, the bat comprising: a wood core including a handle portion and a shaft A body, the two parts forming an elongated piece having external dimensions slightly smaller than those of a standard-sized wooden bat; and a continuous one or more layers of reinforcing fiber sleeve impregnated with a curable resin After lamination, over most of the outer surface of the wood core, the thickness of the layer or layers increases the outer dimensions of the wood core so that the final dimensions of the reinforced bat are comparable to the standard size wood ball The outside dimensions of the bats are the same, and the bat has a plurality of annular grooves in the barrel end.

According to yet another aspect of the present invention, there is provided a reinforced wood bat having the same external dimensions as a standard size wooden bat comprising: a solid wood core including a handle portion and a shaft A body, the two parts forming an elongated solid piece of wood having external dimensions slightly smaller than those of a standard-sized wooden bat; and a continuous one or more layers of reinforcing fiber filament sleeve , which is impregnated with a curable resin and laminated to substantially the entire outer surface of the core, the thickness of the layer or layers increasing the outer dimensions of the core such that the final dimensions of the reinforced bat are the same as The outside dimensions of the standard size wooden bats are the same, and the orientation of the filaments in the shaft portion of the bat is about +45°/-45°, the filaments are The direction in the handle portion of the bat is less than +45°/-45°; the handle portion of the wood core includes a plurality of longitudinally extending grooves symmetrically spaced on the handle portion of the bat.

Description of drawings

These and other objects and advantages will become apparent from the following detailed description of construction and operation taken in conjunction with the accompanying drawings, which form a part of this specification, and in which like parts are designated by like numerals.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front view of a reinforced wood bat of the present invention with a portion of the shaft in section showing the composite laminate on the wood core.

Figure 2 is a front view of the wood core of the present invention showing the original dimensions of a standard size conventional wood bat in dashed lines.

Figure 3 is a front view of a preformed bat assembly of the present invention with a two-layer, preferably braided fiberglass sleeve over a wood core.

4 is an enlarged perspective view of the knob and handle portion of the preformed bat assembly shown in FIG. 3 .

5 is an enlarged perspective view of the shaft or outer end of the preformed bat assembly shown in FIG. 3 .

6 is a partial cross-sectional view of the shaft end or top end of a ball bat showing the majority of the top end of the bat being covered by a reinforced composite laminate.

7 is a partial cross-sectional view of the handle end of a ball bat showing the ball knob of the ball bat being substantially covered by a reinforced composite laminate.

Figure 8 is an enlarged front view of a portion of a braided case of the present invention showing the preferred configuration of the braid.

Figure 9 is a front elevational view, partially in section, showing the sleeve of the present invention and the wood core ready to be inserted to place the first layer of fiberglass sleeve over the wood core.

Figure 10 is an elevational view, partially in section, showing the supporting stub shaft at the top of the bat twisted after the core has been fully inserted into the sleeve so that the first layer of the fiberglass sleeve fits snugly over the outer surface of the core , ready to set the second layer on the wooden core.

Figure 11 is a view similar to Figures 9 and 10, in which the wood core is withdrawn from the casing, thereby placing a second layer of fiberglass sleeve over the outer surface.

Figure 12 is a top view of the lower half of a mold into which a preformed bat assembly consisting of a wood core and layers of fiberglass sleeves is placed for infusion of curable resin lamination reactants.

Figure 13 is a schematic side view of the two halves of a known mold and cavity showing the relationship of the mold to the preformed bat assembly and the ports for injecting curable resin into the mold to impregnate the layers of the sleeve.

14 is an end view of the lower mold half and preformed bat assembly shown in FIG. 12. FIG.

Figure 15 is a side view of an apparatus that simultaneously stretches and shrinks a high shrinkage thermoplastic tube to create a plastic tubular mold.

Figure 16 is a side view of an apparatus in which epoxy resin wets the layers of fiberglass while flowing down a preformed bat assembly in a plastic tubular mold with a strip of ash in the resin as a heat sink.

Figure 17 is also a side view, this time schematically showing an apparatus that supports a preformed bat assembly in a plastic tubular mold with a clamp just below the ball knob of the bat, allowing the epoxy to wet the fiber layers.

Fig. 18 is a side view of a wood core modified from the bat of Fig. 2, showing in phantom the original dimensions of a standard size ordinary wood bat having a plurality of annular grooves in the shaft portion.

Fig. 19 is a side view of a wood core modified from the bat of Fig. 18, showing in dashed lines the original dimensions of a standard size ordinary wood bat, the bat having a plurality of annular grooves in the shaft portion, the grooves Has curved sides.

Detailed ways

In describing the preferred embodiment of the invention shown in the drawings, specific terminology will be used for the sake of clarity. However, the invention is not to be limited to the particular embodiments shown and described and the terms chosen, but it is to be understood that each specific term includes all technical equivalents which work in the same manner and accomplish the same purpose.

As shown in FIG. 1, the reinforced bat 10 of the present invention includes a wood core 12 and a composite laminate 14. As shown in FIG. The composite laminate 14 consists of a continuous, uninterrupted one or more layers of conformed fabric cover covering substantially the entire outer surface of the wood core 12 . The cover is made of high strength fibres, preferably glass fibres, preferably a woven fabric. The braided sleeve is impregnated with a curable resin so that the resin laminates, bonds, the reinforcement layer or layers to the outer surface of the wood core 12 .

The bat 10 is made to have the same dimensions and physical properties as a conventional wooden bat. Rather, conventional wooden bats are manufactured to various standard lengths, various standard weights and standard outside diameters and shapes, and bat 10 is also manufactured to these standards. As with conventional wooden bats, bat 10 includes a handle portion 16 of increasing diameter to merge with a shaft portion 20 terminating in a knob 18 at the end of the handle portion. At a top or outer end 22 .

The wood core 12 is formed by lathe turning the same as the ordinary wooden bat, and also includes a handle portion 17, a shaft portion 19 and a spherical knob 21 on the end of the handle portion. However, as shown in FIG. 2, the outer dimensions of the wood core 12 are slightly smaller than those of conventional wood bats. In FIG. 2, the dashed line indicated at 24 shows the outline of a conventional wooden bat, thereby showing that the outer dimensions of the wood core 12 are slightly smaller than those of a conventional standard size bat. Once the laminate 14 is bonded to the wood core 12, the resulting reinforced wood bat 10 has the same external dimensions as a standard size conventional wood bat. Preferably, the lathe turns the dimension of the wood core along its entire length to about 1/10 inch smaller than a standard wood bat. Thus, for a standard wood bat having a diameter of approximately 2.50 inches, the diameter of the core 12 at the shaft portion 19 is preferably approximately 2.35-2.40 inches.

In addition, when the reduced size core 12 is turned on a lathe, as shown in FIG. 2, the specially sized longitudinal support stubs 26 and 28 projecting axially on both ends of the core 12 are left intact. Outer stub shaft 28 is sufficiently large to be used as a handle when bat 10 is made. Preferably, the minor shaft 28 is about 1 inch in diameter and about 2-3 inches long. The minor axis 26 on the end of the knob is much smaller, about 3/4 inch in diameter and about 1/2 inch long. The handle portion 17 of the wooden core 12 is engraved with longitudinal grooves 30 . These grooves help the resin wet out and impregnate one or more layers of fiberglass sleeve along the handle portion of the wood core. Preferably, the grooves are symmetrically distributed about the circumference of the handle portion and extend about 15 inches or more along the length of the bat from 1 inch from the knob. The effective size and shape of the recess 30 can be arbitrary. Satisfactory results are obtained with four 0.06" x 0.06" square grooves distributed symmetrically around the circumference of the handle.

FIG. 3 shows a preformed bat assembly 32 . The assembly 32 is formed by covering substantially the entire outer surface of the wood core 12 with a continuous, uninterrupted one or more layers of conformable fabric cover 34 . Preferably, a continuous, uninterrupted, two-layer fiberglass braided sheath, indicated at 36 and 38 in FIGS. Although two consecutive layers are preferred, one consecutive layer may be sufficient, or three or more layers may be used, depending on the density of the fiberglass filaments and whether the braid or cover is loosely or tightly woven.

The sleeve 34, which generally remains constant in diameter, is woven or formed with strands perpendicular to each other and at an angle of 45° or +45°/-45° to the longitudinal axis of the core 12. For the purposes of the present invention, the 0° direction of the filaments is parallel to the longitudinal axis of the core 12 or bat 10 and the 90° direction is axially around the core or bat 10 in a plane perpendicular to the longitudinal axis. The plane of the filaments oriented at +45° or -45° is at a 45° angle to the longitudinal axis of the core or bat, and the +45° plane is perpendicular to the -45° plane.

FIG. 8 shows the preferred +45°/-45° orientation of the filaments, wherein the filaments 40 and 42 are perpendicular to each other and make an angle of +45°/-45° to the longitudinal axis of the sleeve 34, respectively. These filaments 40 and 42 are shown in solid lines in FIGS. 3, 4 and 5 for the sake of clarity. The preferred form of the fiberglass cover 34 for a 2.50 inch shaft diameter bat is a braid having an inside diameter of about 2.25 inches, which is slightly smaller than the largest diameter of the core 12, which is preferably about for 2.35-2.40 inches. A preferred braid has a weight and density of about 26.5 feet per pound and 9 ounces per square yard, and is manufactured and sold by A & P Technology of Covington, Kentucky.

While a sleeve woven from fiberglass strands or bundles is the preferred construction for the sleeve 34 used to form the layers 36 and 38 of the present invention, it is within the scope of the invention to use glass fibers and/or other high-strength fiber strands. woven or knitted covers. The woven or knitted cover may or may not have a longitudinal seam. Thus, for the purposes of the present invention, the term "cover" includes not only the preferred woven cover, but any woven, knitted fabric and fabric that can be made into a continuous, uninterrupted fit cover of fiberglass and/or other high strength fibers. other fabrics.

As mentioned above, it is preferable that the inner diameter of the fiberglass sleeve 34 is slightly smaller than the outer diameter of the shaft portion 19 of the wood core 12 . Therefore, the sleeve 34 is slightly stretched when it is pulled onto the shaft portion 19 . The sleeve 34 and the rod body 19 are so tightly fitted together that the +45°/-45° direction of the glass fiber filaments 40 and 42 on the rod body portion 19 of the wood core 12 remains unchanged or increases slightly. This +45°/-45° direction in the shaft portion 19 is indicated by reference numeral 46 in the preformed bat assembly 32 in FIG. 3 and in the enlarged partial view in FIG. 5 .

On the other hand, the sleeve generally does not fit snugly over the wood core 12 at its top end 54 or along its handle portion 17 . By turning the core 12, the top end 54 of the sleeve 34 is tightened on the core 12. FIG. 5 shows this tightening of the sleeve 34 at the top end 54 . It can thus be seen that the shrunken sleeve layers cover the entire surface of the top end 54 except where the bottom surface 44 of the supporting stud 28 protrudes axially from the top end of the core 12 . The top end 54 of the sleeve can be covered and snugly fitted over the bottom surface 44 of the stub shaft 28 by the unique method of the present invention, but any other method can be used to cover the top end of the wood core.

At the same time, tensioning the braided sleeve 34 over the handle portion 17 of the wooden core causes the sleeve to elongate longitudinally over the handle portion. This elongation causes the orientation of the filaments 40 and 42 in the handle portion to be more longitudinal as shown at 48 in FIGS. 3 and 4 . The angle between the filaments 40 and 42 in the handle portion and the longitudinal axis is much smaller than the normal +45°/-45° angle of the braid shown in FIG. 8 . We have therefore found that a continuous, uninterrupted layer or layers of fiberglass or other high strength fibers oriented at +45°/-45° with an inside diameter equal to or slightly smaller than the diameter of the wooden bat shaft The braided cover of is very suitable for making the laminated bat of the present invention. Specifically, when the braided sleeve is placed over the wood core, the larger diameter of the rod stretches the fiberglass strands so that they are oriented at or slightly greater than +45°/-45°. Then, when the layers 36 and 38 are stretched over the core and tightened around the handle portion of the core, the filaments are strongly pulled into directions much less than +45°/-45°. This change in the direction of the filaments toward 0° greatly increases the longitudinal strength of the filaments, thereby enhancing the reinforcement effect of the glass fibers in the handle of the bat. In addition, the stretching and tightening of the braided sleeve makes the filaments in the handle portion lock each other, thereby greatly improving the strength of the filaments in the longitudinal direction. The preferred orientation for the interlocking of the filaments in the handle portion of the bat is from about +20°/-20 to +25°/-25°.

As part of the present invention, we have discovered that preformed bat assembly 32 can be produced by conveniently and quickly applying successive, uninterrupted layers of a preferably woven fiberglass sleeve over the entire surface of wood core 12 using a hollow sleeve. This method is illustrated in FIGS. 9 , 10 and 11 , the sleeve being indicated at 50 . The length of the sleeve is selected to include at least two layers so that pairs of two layers are applied at a time. The sleeve 34 is then placed over the outer surface of a casing 50 whose inner diameter is slightly larger than the largest diameter of the wood core. Any suitable hard plastic tubing with the required internal diameter can be used, but clear PVC plastic tubing is preferred. The proximal end is fastened with a band or the like, as shown at 52 in FIG. 9, either before or after the sheath 34 is placed over the cannula 50. Wood core 12 can be inserted in sleeve 34 and casing at this moment.

After the sleeve 34 is placed on the outer surface of the sleeve 50 , the handle end 17 of the wood core 12 is pushed into the fastening end 52 of the sleeve 34 , thereby pushing the sleeve into the sleeve 50 . Sleeve 34 is pulled under tension from the outer surface of sleeve 50 onto the bat as it is pushed into the sleeve. This longitudinal tension on the sleeve tightens the sleeve to the handle portion 17 of the wood core so that the direction of the filaments becomes the desired longitudinal direction. When the wood core 12 was fully inserted into the sleeve 50, the support stub 28 at the rod end was used as a handle to rotate the wood core. This turning or twisting forces the sleeve 34 to tighten over the outer end 54 of the wood core 12 . The core is rotated until the sleeve tightly wraps around the annular bottom surface 44 of the stub shaft 28 where it meets the top end of the core, thereby completely covering the remainder of the end 54 of the core. At this moment, the first layer 36 of the cover 34 is placed on the wood core 12 .

How many angles the wood core 12 rotates can completely cover the wood core end 54 until the bottom surface 44 of the short shaft 28 depends on the characteristics of the cover, including density, tightness of the braid, and the like. Using the fiberglass braided sleeve described above, the core only needs to be turned about half a turn of the sleeve 34 to wrap around the core end 54 . Because the cover wraps on the bottom surface 44, the wooden core can be withdrawn from the sleeve tube and the cover will not loosen and fall off. Along with the wooden core is extracted from the sleeve tube 50, the second layer 38 of the fiberglass cover 34 is continuously put on. Wooden core 12 on. Thus, two continuous, uninterrupted layers 36 and 38 of high strength sleeve 34 can be easily and quickly applied over the entire outer surface of wood core 12, the layers being held together. In fact, the second layer 38 simply fits over the entire first layer 36 in reverse. As long as the above method is repeated, several layers can also be covered, one layer at a time or two layers in pairs at a time. In addition, the sleeve can be continuously looped over the outer surface of the sleeve 50 from the non-working end.

When the core 12 is withdrawn from the casing 50, the sleeve 34 is sheared a few inches from the support pin 26 at that end of the core. The end 41 of the cover layer 38 is then tensioned relative to the wood core 12 so that the cover is tightened on the handle portion 17 of the wood core as described above and the layer 38 is in the direction of the filaments 40 and 42 in the handle portion 17 of the bat. Change to desired interlock orientation. This tensioning can be achieved simply by grasping the outer end 41 of the layer 38 while turning the wood core using the support stub 28 as a handle. In addition, the tube is pressed against the bottom surface of the knob 21 so that the sleeve fits tightly over the knob end. To do this, a short PVC plastic tube 39 can be slipped over the layer 38 and the short shaft 26, the end of the braid being pulled taut as the PVC tube is pushed against the bottom surface of the knob 21. The ends 41 of the layer 38 are then folded up and fastened with tape (not shown). If necessary, the outer layer 38 can be further tensioned by screwing the tube 39 against the bottom surface of the knob 21 . A preformed bat assembly is thereby produced.

Bat 34 is formed by firmly bonding layers 36 and 38 of cover 34 to the entire outer surface of core 12 with a suitable curable resin. Any curable resin can be used as long as it bonds the fiberglass layers firmly to the wood core without cracking, breaking or chipping when the ball is struck. Also, since the reinforced bat of the present invention should look like a standard wooden bat, it is preferable to use a clear resin. Therefore, the curable resin of the present invention should have transparency, crack resistance, impact resistance, high adhesion between layers and surfaces, and a high elastic modulus capable of dissipating energy in a direction perpendicular to the velocity vector. quantity.

Preferred resins of the present invention are thermosetting epoxy resins that cure automatically at near or at room temperature. The epoxy base is preferably based on 2,2'-(1,3-phenylene)bis-2-oxazoline oxazoline. Other difunctional and polyfunctional epoxy resins can also be used with or without monofunctional diluents. Converting or curing agents that can be used to generate thermosetting epoxy resins include polyfunctional primary and secondary amines, Lewis acids, Lewis bases, dibasic carboxylic acids and anhydrides, and the like. Preferred curing agents include alkylamines such as diethylenetriamine, triethylenetriamine, m-xylylenediamine, and alpha-aminoethylpiperazine. Polyoxypropyleneamines, amidoamines, polyamides and cycloaliphatic polyamines can also be used as total converting agents or mixtures. The mixing ratio is roughly stoichiometric (except for Lewis acids and bases), and each epoxy group includes an active amine hydrogen. In addition to the epoxy component and the amine curing component, there may be a third component which precipitates out on cure to form a discrete second phase. The second phase is elastic globules, preferably less than 1 micron in diameter, sandwiched and bonded within the continuous epoxy phase. The second phase increases crack resistance, impact resistance so that the layers of the composite do not separate prematurely. The preferred resin material is manufactured and sold by Applied Polymeric Inc. of Benicia, California.

In order to improve the adhesion of the preferred epoxy resin to the bat core, it is preferred to apply a primer to the bat core before the layers of the fiberglass cover are applied to the core. The primer penetrates into the wood and acts as a bond or interface between the wood core and the glass fibers. Preferably, the primer component is epoxy resin latex with low toxicity, low cost, long pot life, strong permeability, Tg>60°C and low viscosity. A one-part thermoplastic epoxy resin with a molecular weight of about 30,000 and suitable coagulation and penetrating solvents is particularly effective. Satisfactory results can also be obtained with a two-part epoxy resin, where part B contains a mixture of alkylamine, amidoalkylamine, and surface-active emulsifier, but due to the two-component and pot life Shorter and not as good as the one-part epoxy above. Other examples of primer compositions include aqueous solutions of resorcinol formaldehyde, urea formaldehyde, and polyethylenimine hydroxymethylated resorcinol. This preferred primer is also manufactured and sold by Applied Polymeric Corporation.

The enlarged cross-sectional views of FIGS. 6 and 7 show that the layers of the composite cover 14 and the surface of the wood core 12 are firmly bonded and laminated together to form the reinforced bat 10 . As shown, the layers 36 and 38 of the cover 34 cover the entire surface of the outer bat 10 at a portion 56 of the outer end 22 and a portion 58 of the bottom surface of the knob 18 where the minor axes 28 and 26 are in the center of the ball. After the rod 10 is made, it is cut off. Furthermore, according to the invention, the knob does not need to be reinforced. Accordingly, reinforcement layers 36 and 38 may be severed at 60 where knob 18 meets the bottom of handle portion 16 . In this case, the minor axis 26 is cut flush with the bottom surface of the knob 18 when the bat is manufactured. Thus, in accordance with the present invention, the reinforcing layers of the fiberglass sleeve cover continuously at least from the junction of the knob and handle 16 to the portion 56 of the outer end of the bat. This continuous uninterrupted cover that does not cover the knob 18 covers more than 99% of the bat surface.

Figures 12, 13 and 14 illustrate a known method of bonding and laminating the layers of a fiberglass jacket to a wood core. The preformed bat assembly 32 is placed in a mold 62 which includes a lower mold half 64 and an upper mold half 66 each having a cavity half 68 for receiving the preformed bat assembly 32 . The components of the mold are known and, when closed, a suitable curable thermoset or thermoplastic resin is injected from the injection port 70 into the mold cavity 68, thereby impregnating the entire fiberglass jacket layers 36 and 38 with the resin. The mold cavity and preformed bat assembly, including the resin-impregnated layers 36 and 38, are subjected to heat and pressure, the temperature of which melts and fuses the resin to securely bond and laminate the cover layers to the wood core and also to The glass fiber strands of the handle portion 16 are kept in a favorable direction indicated by reference numeral 48 , and the fiber strands of the shaft portion 14 are maintained in a diagonal direction indicated by reference numeral 46 . A known injection molding process is described in US Patent No. 5,301,940 to Seki, except that the mold must be modified to accommodate the end support stubs 26 and 28 .

Another part of the invention is the use of a novel method of applying and curing an epoxy resin such as the preferred epoxy described above to securely bond and laminate the layers of the fiberglass sleeve to the wood core. However, when using this preferred epoxy resin, the wood core 12 should be coated with a primer such as the above-mentioned preferred epoxy primer before the layers of the fiberglass cover. The wood core 12 is preferably heated to about 110°F before priming. This heating not only removes air from the wood core, but also helps the primer penetrate the wood. After heating, the wood core is dipped in the epoxy primer. After drying, the wood core is preferably immersed in the primer again, but this time without heating. Epoxy resin can then be applied to the primed wood core in a curing and molding operation.

In accordance with the present invention, a unique molding process has been discovered which allows for the bonding and lamination of the layers of the fiberglass sleeve to the wood core more easily and quickly than prior art, but at a reduced cost. The preferred molding process utilizes a common plastic tube that is heat shrunk and snugly fit onto the preformed bat assembly as a mold for applying and curing the epoxy. The molding process is described below with reference to Figures 15, 16 and 17, in which the plastic tubular mold is indicated by reference numeral 72.

To create the desired tubular mold 72, a suitably sized hollow tube 74 is fitted over the short shaft 28 at the barrel end of the assembly 32. The tube 74 includes a long tube portion 76 and a short tube portion 78 sleeved on the short shaft 28 . The tube portion 78 fitted over the short shaft 28 has a smaller diameter than the tube portion 76 . The large diameter tube portion 76 forms the feed port of the mold 72, while the short tube portion 78 forms the annular hole 81 from the feed port 80 into the die encasing the preformed bat assembly (see FIG. 16). Generally, a 1 -inch cardboard hollow tube about 20 inches long can be used for the tube portion 76. The short tube portion 78 is conveniently glued to the inner surface of the cardboard tube portion 76 . The bottom of the tube 74 may rest on a suitable support (not shown) which supports the tube 74 in a vertical position. The support stub 28 is then inserted into the stub portion 78 to support the preformed bat assembly 32 on the tube 74 .

A high shrink tube 82 having a flattened width of about 4 inches is then placed over the preformed bat assembly and tube 74. Pipe 82 can use thin-walled PVC high-shrinkage tube. Then use an annular radiant heater 84 or the like to shrink the high-shrink tube 82 to tightly fit the outer layer of the fiberglass sleeve. Preferably, the radiant heater 84 moves automatically from the bottom end of the tube 82 and upwardly from the outer end of the preformed bat assembly 32 . As shown in FIG. 15, the annular radiant heater 84 is moved up the assembled configuration through the tube 74, the shaft portion 19, and the handle portion 17 of the preformed bat assembly 32. As shown in FIG. As shown, the high shrink tube 82 shrinks over the tube 74 and the preformed bat assembly 32 . As the tube 82 shrinks over the tube 74 and preformed bat assembly 32, air is removed from the tube with a suitable hole. Once the radiant heater has passed through the entire assembly, with the tube 82 snug over the knob end, the hollow tube 74 is withdrawn, leaving the preformed bat assembly 32 encased in a heat-shrinkable plastic shell forming the plastic tubular mold 72, An open tube extension 85 is formed at the barrel end 54 .

Due to the large difference in diameter between the handle portion 17 and the shaft portion 19 of the bat, the method of tightening the tubular mold onto the handle portion of a preformed bat assembly requires that the plastic mold tube be heated during this heat shrinking process. While stretching the plastic mold tube, the mold tube is tightened on the handle portion of the bat. The mold tube is simultaneously stretched during this heat shrinking process in the handle portion 17 of the bat by any suitable method. However, a simple approach is to unsupport the tube 74, and the preformed bat assembly thereon, when the annular radiant heater 84 moves upward about 3/4 of its travel, so that the preformed bat assembly 32 And the portion of tube 74 with tube 82 heat-shrunk thereon is suspended relative to the remainder of tube 82 supported from above. The gravitational force acting on the uncontracted portion of the tube 82 causes this portion to be stretched as it is thermally contracted by the radiant heater 84 so as to fit snugly over the handle portion.

After the tube 74 has been withdrawn from the tube extension 85, the preformed bat assembly 32 in the plastic tubular mold 72 is injected, preferably with epoxy resin 86. Components were placed in a room temperature environment. The components of the epoxy resin are mixed and injected into the hollow tube extension 85 from the feed port 80 . If using the preferred epoxy resin, only 7 oz of mixed resin should be injected. Preferably, an approximately 1 inch square, 14 inch long ash slender strip 88 is inserted into the tube as a heat sink. The strip is used to slow down the exothermic reaction of the epoxy resin, increasing the working time or "pot life" of the resin. The open end 80 of the hollow tube extension 85 is then inserted into a clamp 90 and clamped, increasing the air pressure in the tube extension and the plastic tubular mold. This air pressure forces the resin to wet out the layers of the fiberglass cover in the preformed bat assembly for a reasonable period of time without premature curing. Preferably, an air pressure of about 10 psi is used so that the epoxy resin flows through the entire length of the supported preformed bat assembly 32 and plastic tubular mold 72 so that after about 30-40 minutes the resin begins to flow from the mold to the surface of the assembly 32. The opening 92 at the handle end drips out. As shown in FIG. 16 , the epoxy resin has wetted out about 1/4 of the preformed bat assembly 32 at the level shown at 94 . This pressurization of the plastic tubular mold is a composite manufacturing method known in the prior art as "Resin Transfer Molding (Resin Transfer Molding)".

We have found that the optimum room temperature for application and curing of epoxy resins is about 80-82°F. If the room temperature is lower than this temperature, the viscosity of the resin will be increased, causing the soaking time to be too long. Room temperature above this temperature will not favor the exothermic reaction of the resin, thereby damaging the resulting bat.

After the preformed bat assembly 32 is wetted, it can be held upside down with a clamp 96 to hold the bat just below the knob 18 (see FIG. 17). This allows the uncured resin and fiberglass to better fill the handle/knob interface. Preferably, the clamp 96 is formed to form a permanent ring at the junction of the top of the ball knob 18 and the bottom of the handle portion 16 of the bat when heated to above 200°F. This clamping step is not necessary if the layers of the fiberglass sleeve are effectively saturated during the resin transfer molding step described above.

After the epoxy resin is solidified in 1-2 hours, the tubular mold 72 is removed, that is, the heat-shrinkable shell. After cutting off the supporting short shafts 26 and 28, the exposed bat ends are trimmed. The handle is then sandblasted to give it a rough look. Although several preferred embodiments have been described above using one or more layers of conformable fabric covers made of high strength fiberglass, the present invention may also be used with fabric covers made of other high tensile strength fibers such as Kevlar Fibers such as Kevlar, Spectra, carbon fiber, and nylon fiber. In addition, within the scope of the present invention, the above-mentioned other high-strength fiber filaments can be braided, woven, and knitted together with the glass fiber filaments to form a fitting cover. Accordingly, the present invention is not limited to covers woven or made from only fiberglass.

In addition, various types of wood can be used for the wood core 12 . High quality ash is typically used to make high quality wooden bats, and this type of wood can be used with the present invention. However, due to the extremely high strengthening effect of the laminated fiberglass sleeve 14 of the present invention, lower quality ash wood can also be used for the wood core 12 .

Finally, the embodiments of Figures 18 and 19 disclose improved bats 100 and 200, respectively. There are a plurality of annular grooves 102 in the bat 100 of FIG. 18 . As shown, there are 15 grooves, each about 3/16 inch wide and about 0.100 ± 0.010 inch deep. A strip about 3/16 inch wide is left between each pair of grooves in the rod body. A longitudinal groove 110 is also shown. There is also a corresponding groove 110 on the reverse side of the bat 100 . The two grooves 110 are about 1/32 inch wide and the same depth as groove 102 . Like the four grooves 30 at the handle end, the grooves 110 are used to expel air from the grooves 102 as the resin flows from the shaft end to the knob end. Since the braid is looser at the rod end and the resin flows faster at the rod end, compared with the four grooves 30 at the handle end where the braid is tighter and the resin flows slowly, the rod end needs only Two grooves 110 .

Like grooves 102 of bat 100 , bat 200 of FIG. 19 includes a plurality of grooves 202 . However, the outer (206) and inner (207) sides of the recess 202 are arcuate. The longitudinal section of the groove 202 is sinusoidal. (In the bat of Fig. 18, the cross section is square.) If a line is drawn along the surface of the shaft, the top of the strip between each pair of grooves 202 touches the line. The bat 200 is shown without the longitudinal groove 110 of the bat 100 . Since the shape of the groove is a sine wave, there is no need to use another air channel to discharge the air in the groove 202 . Furthermore, it is easier for the flowing resin to fill the grooves 202 . However, the groove 110 may be used if necessary.

Bats 100 and 200 are made in the same manner as bat 10 described above. It's just that there is more resin in the shaft end, which helps prolong the life of the wood in the hitting zone of the bat. For bats 100 and 200, 100 parts of Applied Polymeric's CR-58 epoxy resin was mixed with 28 parts of Applied Polymeric's HB-3 hardener. Using 100 grams of this mixture in a bat mold, about 80-90 grams actually flowed through the bat.

The foregoing should be considered as illustrative of the principles of the invention. Various modifications and changes can be made by those of ordinary skill in the art. Therefore, the invention is not limited to the exact construction and operation shown and described. All suitable modifications and equivalents are intended to fall within the scope of the invention.

Claims (16)

1, a kind of ball stick made of reinforced wood, its external dimensions is identical with a standard-sized wooden bat, this bat comprises: a reel, this reel comprises a shank and a rod-rod-body on the other hand, these two parts form an elongate articles, and the external dimensions of this elongate articles is slightly smaller than the external dimensions of standard size wooden bat; And one or more layers continuous reinforcing fiber cover, it floods the back lamination, covers on most of outer surface of described reel with curable resin, described one or more layers thickness increases the external dimensions of reel, thereby make that the final size of this reinforcement bat is identical with the external dimensions of described standard size wooden bat, the handle portion of this reel comprises a plurality of extending longitudinally grooves that are distributed in symmetrically on the bat handle.

2, by the described ball stick made of reinforced wood of claim 1, it is characterized in that described cover is made with described filament.

3, by the described ball stick made of reinforced wood of claim 1, it is characterized in that the major part of described fiber is made of glass fibre.

4, by the described ball stick made of reinforced wood of claim 2, it is characterized in that, the direction of described filament in the rod-rod-body of described bat be about+and 45 °/-45 °.

5, by the described ball stick made of reinforced wood of claim 4, it is characterized in that the direction of described filament in the handle portion of described bat is less than+45 °/-45 °.

By the described ball stick made of reinforced wood of claim 5, it is characterized in that 6, the filament on the described direction is roughly locking in the handle portion of bat.

7, by the described ball stick made of reinforced wood of claim 3, it is characterized in that described glass fibre cover comprises two pantostrats, each layer all covers the almost whole outer surface of reel.

8, by the described ball stick made of reinforced wood of claim 1, it is characterized in that described one or more layers bottom surface from handle portion covers more than 99% of described reel outer surface to the bat outer end.

9, by the described ball stick made of reinforced wood of claim 1, it is characterized in that described bat has a kob in the handle portion end, the described two-layer at least major part that all covers kob.

10, by the described ball stick made of reinforced wood of claim 1, it is characterized in that the outer surface of described reel is with agent dipping at the bottom of the emulsification, this end agent when one or more layers is laminated on the reel and described curable resin bonding.

11, a kind of ball stick made of reinforced wood, its external dimensions is identical with a standard size wooden bat, this bat comprises: a reel, this reel comprises a shank and a rod-rod-body on the other hand, these two parts form an elongated ligneous piece, and the external dimensions of this elongated ligneous piece is slightly smaller than the external dimensions of standard size wooden bat; And one or more layers continuous reinforcing fiber cover, this reinforcing fiber cover major part is made by glass fibre, and with curable resin dipping back lamination, cover on the almost whole outer surface of described reel, described one or more layers thickness increases the external dimensions of reel, thereby make that the final size of this reinforcement bat is identical with the external dimensions of described standard size wooden bat, described cover comprises two pantostrats, each layer all covers the almost whole outer surface of reel, described two pantostrats are also continuous mutually, and skin oppositely is stacked on the internal layer.

12, a kind of ball stick made of reinforced wood, its external dimensions is identical with a standard-sized wooden bat, this bat comprises: a reel, this reel comprises a shank and a rod-rod-body on the other hand, these two parts form an elongate articles, and the external dimensions of this elongate articles is slightly smaller than the external dimensions of standard size wooden bat; And one or more layers continuous reinforcing fiber cover, it floods the back lamination, covers on most of outer surface of described reel with curable resin, described one or more layers thickness increases the external dimensions of reel, thereby make that the final size of this reinforcement bat is identical with the external dimensions of described standard size wooden bat, described bat has a plurality of annular grooves in described excellent body end.

13, by the described ball stick made of reinforced wood of claim 12, it is characterized in that described groove and described excellent body have cross transition.

14, by the described ball stick made of reinforced wood of claim 12, it is characterized in that described groove and described excellent body have the arc edge transition.

15, a kind of ball stick made of reinforced wood, its external dimensions is identical with a standard size wooden bat, this bat comprises: a solid reel, this reel comprises a shank and a rod-rod-body on the other hand, these two parts form an elongated solid wood product, and the external dimensions of this elongated solid wood product is slightly smaller than the external dimensions of standard size wooden bat; And one or more layers continuous reinforcing fiber silk braid, it floods the back lamination, covers on the almost whole outer surface of described reel with curable resin, described one or more layers thickness increases the external dimensions of reel, thereby make that the final size of this reinforcement bat is identical with the external dimensions of described standard size wooden bat, and, the direction of described filament in the rod-rod-body of described bat be about+and 45 °/-45 °, the direction of described filament in the handle portion of described bat is less than+45 °/-45 °; The handle portion of this reel comprises a plurality of extending longitudinally grooves that are distributed in symmetrically on the bat handle.

16, by the described ball stick made of reinforced wood of claim 15, it is characterized in that described bat has a plurality of grooves in described excellent body end.

Images