JPH0124513B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reinforced plastic baseball bat having a so-called FRP structure in which glass fiber or the like is used as a reinforcing material and is impregnated with a thermosetting resin, and a method for manufacturing the same.

In recent years, the development of plastic products has been remarkable, especially the development of reinforced plastic products that provide strength, and attempts have been made to mold baseball bats using reinforced plastic. For example, there is a baseball bat made of reinforced plastic, as seen in Japanese Patent Publication No. 49-28614. This simply involves injecting a mixture of resin and reinforcing glass fiber into the gap between the shaped tube that defines the wall thickness of the bat and the split mold, and then solidifying it to form the bat. In other words, this type of bat up until now is
The reinforced plastic material injected into the mold is a mixture of thermosetting resin (or thermoplastic resin) and glass fiber chops (chop strands) that serve as reinforcing materials. The process is simple, just injecting it into the gap and making a mold.

Therefore, since the baseball bat obtained by this processing method uses short fibers as the reinforcing glass fiber, even if hardness is obtained, it is difficult to create the desired deflection in the tapered part that is originally required for the bat. It is difficult, has little repulsive force, and is likely to break. In particular, the problem of using a hardball ball could not be overcome at all, which was the reason why it did not become popular. Of course, this structure is prone to cracks because short glass fibers are used and the orientation of the fibers is uneven due to simple injection molding (see FIG. 9). In addition, because the plastic was left exposed, it was subject to severe UV deterioration, which also made it unsuitable for use as a baseball bat for playing outdoors.

In view of the above circumstances, the present invention has been developed to provide a baseball made of reinforced plastic that has a flexibility comparable to that of a wooden baseball bat, and that is safe and durable for long-term use, with no broken pieces at the taper or batting part flying off even if it breaks. The object of the present invention is to provide a bat and a method for manufacturing the same.

That is, the present invention uses glass fibers as a reinforcing material for reinforced plastic to form a hollow butt with a glass fiber bundle (hereinafter referred to as a bristle) having a predetermined butt length and an appropriate number of fine iron wires arranged between the bundles with the fiber direction as the longitudinal direction. A base layer is formed, and a roving cloth (woven from untwisted fiber bundles) layer is formed on the hollow butt base layer, and a bias cloth layer is further provided at the ball-hitting portion, and glass paper is wrapped around this entire area. Another invention relates to the structure of a baseball bat made of reinforced plastic, in which a multilayer reinforcing material bat shell is formed, and a metal film is arranged on the surface of the bat body, which is formed by impregnating this bat shell with a predetermined resin. This is a manufacturing method for manufacturing names. That is, a blind body made of bristle and an appropriate number of fine iron wires is wound around a batt core mold in the longitudinal direction of the batt in the direction of the fibers, and in this state, a roving cloth is wrapped on top, and at least this ball hitting part is wrapped around the batt core mold. Wrapping bias cloth tape around the area, then wrapping glass paper around the entire area to make the weave finer, and applying glass surface treatment to this to create a multi-layer reinforcing material butt shell.
A process of setting the batt shell together with a batt core mold serving as a core material into a liquid injection mold, injecting resin in liquid form to form a reinforced plastic batt body, and removing the batt core mold while the batt body is in a semi-hardened state. This method of manufacturing a baseball bat includes the steps of joining the head top and grip end, and then depositing a metal film with a light-reflecting effect on the surface of the bat body to prevent deterioration from ultraviolet rays.

Hereinafter, the present invention will be explained based on the drawings of embodiments.

First, straight brittle 1 having a dimension of at least butt length l, and fine iron wire 2 made of wire, piano wire, etc. are arranged at appropriate intervals between the groups of 1 group of brittle, and are bound with binding thread 3 such as synthetic fiber or cotton thread. The formed glass fiber screen 4 is wound several times (for example, 4 times) around a bat core mold 5 having an outer shape that occupies the hollow area of the hollow bat, with the fiber direction being the longitudinal direction of the bat.
The screen body 4 is used as a hollow bat base layer 4', and this screen body 4
The edges of the roving cloth 6 are temporarily fixed with an appropriate adhesive (not shown), and a roving cloth 6 having the same butt length l is wrapped around the surface several times (for example, twice), and the edges are fixed with an adhesive. The roving cloth layer 6' is then fixed.
Furthermore, the bias cloth tape 7 made of the same glass fiber is sequentially wound around the ball hitting portion a to form a bias cloth layer 7' having a thick impact-resistant thickness. In this case, the direction of winding the second layer is
The cross orientation is opposite to the wrapping direction of the first layer, which is the base layer. Also, a part of the tapered portion reaches the position b to adjust the inclination. After this,
A thin glass paper 8 having a fine weave is wrapped several times (for example, 5 to 6 times) over the entire area of the bias cloth layer 7' and the roving cloth layer 6' which becomes the non-bias cloth surface, and the various layers as a whole are butt-reinforced. Let it be material 9. Thereafter, the butt reinforcing material 9 is pushed together with the butt core mold 5 into a shell mold (not shown) whose surface is coated with Teflon, polyethylene, etc., and then subjected to glass surface treatment, which is a known coupling treatment, and dried. . After drying, the shell is cured to form a butt shell 9' that has good adhesion to the resin.
get.

Next, the butt shell 9' taken out from this shell mold is set together with the butt core mold 5 into a liquid injection mold 10 exhibiting a two-part mold (Figs. 4A and B).
reference). This liquid injection mold 10 is a vertical type,
A vacuum pump 11 for obtaining negative pressure is provided on the upper end side, and a resin pressure feeding tank 12 for injecting resin is provided on the lower end side.

Here, while the vacuum pump 11 is driven to create a vacuum inside the cavity 10a, the resin pressure feeding tank 1 is
2, a thermosetting resin 13 such as polyester resin, epoxy resin, diallyl phthalate resin, methacrylic resin, phenol resin, melamine resin, silicon resin, furan resin, etc. is injected under vacuum, and air bubbles remain in each glass fiber layer and in the resin. The butt shell 9' (the hollow butt base layer 4', the roving cloth layer 6', the bias cloth layer 7', and the glass paper 8) is impregnated to prevent this from occurring. Furthermore, this resin 13
The injection state is monitored in the glass tube 14 provided at the upper end.

Thereafter, the liquid injection mold 10 is heated (for example, 70 to 220°C), and when the resin 13 injected into the cavity 10a is in a semi-hardened state, the liquid injection mold 1
0 is opened and the bat main body 15 made of semi-hardened reinforced plastic and the bat core mold 5 are separated from the inside, and in this state, the bat core mold 5 is extracted from the bat main body 15. Next, for the bat body 15 without a head top and grip end, a thread groove 16 is provided in the tip opening 15a of the bat body 15 after hardening, and a threaded shaft of the head top 17, which is separately formed, is provided in the thread groove 16. If the parts 17a are screwed together using substantially the same resin as an adhesive, they will be completely cured and become one piece. In this case, the shape of the head top 17 is such that it sinks into (covers) the tip opening 15a, and the periphery of the head top 17 is not used as the outer periphery of the top to prevent damage (see FIG. 5). If it is desired to add weight to the bat, an additional weight tube 18 made of plastic as shown in FIG. 6A is inserted into the impact center of the hollow ball hitting portion a of the bat body 15. This additional weight tube 18 has a cutout window 18 on the base end side.
In addition to the thickness of the additional weight tube 18 itself, the weight can also be adjusted freely. The additional weight tube 18 is held immovably between a fitting step 19 formed at the rear end and a head top 17 fitted at the rear end. In addition, as a simple structure for adding weight, a reinforced plastic piece 20 made of the same material may be simply laminated on the inner wall surface of the ball hitting part a as shown in FIG. 6B while being heated by guiding a heater 21, for example. .

On the other hand, in the case of the grip part, the threaded shaft part 22a of the separately formed grip end 22 is connected to the threaded groove 15 disposed in the end opening 15b of the bat body 15.
6' together with resin, the whole becomes one reinforced plastic bat 15'.

Finally, in order to prevent deterioration by ultraviolet rays on the surface of this bat 15', a metal film 23 such as aluminum is deposited over the entire area to reflect sunlight.
Of course, when providing the product as a bat product, the surface of the bat 15' is subjected to other appropriate treatments such as top coating 24, surface polishing 25, and stamping 26 such as marks. Furthermore, a resin layer 27 with high water absorption is provided on the grip portion c to provide a non-slip structure.

Although the above description uses glass fiber as the reinforcing material, it is possible to use carbon fiber to obtain strength with even higher elastic modulus.

Example: A bat core mold with a winding length of 99 cm, a large diameter of the ball hitting part of 54 mm, an intermediate diameter of the taper part of 28.5 mm, and a small diameter of the grip part of 17.5 mm, has a blind body made of 1 ^m2 of brittle including 10 fine iron wires. Roll 4 times and place 0.6m ² on this surface.
2 wraps of roving cloth, then 2 wraps of 0.4 m ² bias cloth tape at the ball hitting position of the roving cloth surface, and 5 wraps of 1 m ² glass paper over the entire area to form a glass fiber butt reinforcement material. After applying glass surface treatment to this,
The bat shell was set together with the core mold in a cavity of a liquid injection mold with a large diameter of the ball hitting part of 65 mm, an intermediate diameter of the taper part of 34 mm, and a small diameter of the grip part of 25.5 mm, and approximately 300 g of polyester resin was injected in liquid form (at a vacuum level of -2 to 3", injection pressure 0.1~2.0Kg/cm ² ), then heat the liquid injection mold at 70~220℃ for 20~30 minutes, and when the resin is in a semi-hardened state, take it out from the liquid injection mold and remove the core mold. A 20 g head top and a 15 g grip end were inserted into the upper and lower ends of the bat body to obtain an 850 g reinforced plastic baseball bat.

As described above, the reinforced plastic baseball bat of the present invention and the method for manufacturing the same consist of making a hollow bat by wrapping a glass fiber bundle having the length of the bat or, if necessary, a blind body having carbon fiber bristle and thin iron wire several times. A base layer, on which a roving cloth layer with a finer weave, a bias cloth layer, and a glass paper layer are arranged in order to form a butt shell, which is impregnated with resin to form the butt body, and a metal film is further arranged on the surface. By doing so, when swinging, the blitzle directed in the longitudinal direction of the bat and the so-called "waist" of the thin iron wire combine to provide the same flexure as a wooden bat. That is, since each brittle is one length along the entire length of the butt, a suitable degree of deflection can be obtained. If you want to stiffen this deflection, you can make the glass fibers in each unit of the blitzle thicker, and if you want to make it softer, you can use thinner fibers to make it more adjustable. (Because an unexpectedly large force is applied when the ball and butt collide, the glass fibers of the bristle must pass from the tip of the butt to the end of the grip.) Of course, the desired deflection and impact resistance strength at the ball hitting portion can be freely set by distributing and combining the glass fibers having various shapes. Furthermore, since the brittle that serves as the reinforcing material has a thin iron wire and also serves as a connecting member, even if the brittle breaks during impact, there is no risk of the broken end flying off due to the connecting action of the fine iron wire. Furthermore, since the bat surface is coated with a metal film to prevent UV deterioration, even if left outdoors, it will not suffer from UV deterioration, which is a disadvantage of plastic.
In addition, since it does not contain water like wooden bats, it is easy to use in rainy weather and to clean afterwards. Furthermore, while wooden bats are limited in their striking surface to hitting only in the straight grain direction, this reinforced plastic bat has no such direction and can be used easily. In addition, stamping on the surface is also possible,
For example, if you mark the ball hitting area with marks such as north, south, east, and west,
Each direction can be used evenly. However, the batt forming method of the present invention is a simple and reliable reinforcement method in which a core mold is wrapped with a blind made of brittle and thin iron wire, and then other glass fiber fabrics with different weave patterns are sequentially wrapped and laminated on top of this. Since the batt is made of material and impregnated with resin, it is easy to manufacture and is lightweight and inexpensive. The batting sound and feel of this reinforced plastic bat are almost the same as those of wooden bats, and there is no discomfort like that of metal bats.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; Fig. 1 is a front view, Fig. 2 is a front view of the screen body, Fig. 3 is an explanatory diagram of the structure of the reinforcing material, and Fig. 4 A and B are liquid injection. A front view and a plan view showing the inside of the mold part, Figure 5 is an explanatory diagram of the head top part attached, Figures 6 A and B are explanatory diagrams of the additional weight structure, and Figure 7 is an explanatory diagram of the grip end part attached. Explanatory drawings, Figures 8A, B, and C are enlarged cross-sectional views of Figure 1 - line (ball hitting part), - line (tapered part), - line (grip part), and Fig. 9 is a conventional reinforced plastic product. It is an explanatory view showing fiber orientation of a baseball bat. 1... Blitzle, 2... Thin iron wire, 4... Blind body, 4'
...Hollow butt base layer, 5...Butt core mold, 6...Roving cloth, 6'...Roving cloth layer, 7...
Bias cloth tape, 7'...bias cloth layer,
8...Glass paper, 9...Butt reinforcement material, 9'...
Butt shell, 10... Liquid injection mold, 13... Resin, 15... Butt body, 23... Metal film.

Claims (1)

[Scope of Claims] 1. A hollow bat base layer of bristle having a bat length in which thin iron wires with the fiber direction oriented in the longitudinal direction of the bat are appropriately interposed, a roving cloth layer on the hollow bat base layer, and a bias cloth layer on the ball hitting part of the hollow bat base layer. and,
This baseball bat made of reinforced plastic is characterized by forming a multi-layer reinforcing material bat shell with a glass paper layer arranged over the entire area, and disposing a metal film on the surface of the bat body formed by impregnating the bat shell with resin. 2 Wrap a blind made of straight glass fiber or the like with a small amount of thin iron wire arranged at appropriate intervals around a bristle made of straight glass fiber or the like having at least a butt length several times around a butt core mold with the fiber direction as the longitudinal direction of the butt to form a hollow butt. A base layer is formed, and in this state, a roving cloth is wrapped around the outer periphery, and a bias cloth tape made of the same glass fiber is wrapped several times around the outer periphery of the ball hitting part of the roving cloth layer to make it impact resistant and thick, and over the entire length of the butt. A process of wrapping glass paper and subjecting it to glass surface treatment to form a multilayered reinforcing material bat shell, and setting the bat shell together with a bat core mold into a liquid injection mold and injecting resin in liquid form to form a reinforced plastic bat body. 1. A method for manufacturing a reinforced plastic baseball bat, comprising the steps of: forming a baseball bat, and depositing a metal film for preventing ultraviolet deterioration on the surface of the bat body.