JPS605311B2 - Manufacturing method of metal body for ball butt - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Batting bats vary depending on the particular game being played, but a common bat has a handle for gripping the bat at one end and a portion for hitting the ball at the other end. It has characteristics.

For example, in the case of American baseball, there are bats used by professionals for hardballs and bats used for softballs.
There are differences between bats used for and Little League games, but generally one of these uses is
The design can also be adapted to two other applications. Wooden bats have been traditional for many years in all three types of American baseball.

However, the intertwining of population growth and declining wood resources has led to the search for other materials for bat manufacturing. All kinds of metals can be used, but
Aluminum and aluminum-based alloys are particularly suitable for this purpose when considering strength to weight ratio, surface properties, formability, and cost. Aluminum bats are currently more expensive than wooden bats, but aluminum has a significant advantage in terms of durability and is therefore cheaper in the long run. In early efforts to develop aluminum butts, an extruded aluminum cylindrical tube was mounted on a lathe and the pressure of a round tool forced the cylindrical tube as it was rotated with an inner forming mandrel. The method used was to press it against the outside of the workpiece to make it thinner.

The resulting metal bat material has the original extruded shape along one end that is meant for hitting and a reduced diameter at the other end that is meant for hitting. was. A bat made in this manner had a generally constant metal wall thickness from one end to the other. The tapered end metal was forced longitudinally away from the center of the bat, lengthening the original cylindrical extrusion. Because the wall thickness was constant in relation to the reduced diameter of the handle end, there was less metal per unit length in the tapered handle end of the bat. As a result, the center of gravity of the bat was offset from the geometric center of the length of the bat in the direction of the ball striking portion of the bat. Therefore, in bats made in this manner, the metal weight is concentrated toward the end of the ball. The weight must be at its best at this end, and in conventional solid wood bats, the weight originally exists at this end. Unfortunately, this attenuation process is relatively expensive, and this method of manufacturing bats was clearly never adopted on a large scale commercially, despite successful product testing. Improvements to early aluminum bats were made on November 8, 1969.
No. 3,479,030 to Merola, issued in 1999.

According to the teachings of this patent, a length of cylindrical aluminum extrusion is swung into a rotating die with a tapered throat, and one end of the extrudate is swaged down into the throat. is pushed in. As the die rotates, the metal is compressed radially without significant longitudinal displacement. As compression occurs, the metal material is driven deeper into the die until the workpiece completes a predetermined movement into the die. As explained in that patent, the material of the metal bat thus formed is equal in weight along its length from one end to the other. A minimal counterbore is provided at the thickened, reduced end to facilitate insertion of the wooden screw, but this has no substantial effect on the weight distribution of the metal within the bat. Although the ball-striking end of the bat is stuffed with a relatively large piece of material with a considerable weight, the fact is that the end of the handle is padded from a weight distribution standpoint for the purpose of good pinch-hit characteristics. There is now more metal than desired. However, bats can nevertheless be made relatively cheaply by this method, and they have since proved a commercial success on a considerable scale. Another improvement is disclosed in Swenck, US Pat. No. 3,691,625, issued September 19, 1972.

According to the teachings of this patent, the zero swaging operation described above with respect to the Merola patent is followed by boring to remove excess metal from the thick handle end of the work piece. This treatment gives the bat a better weight balance for hitting purposes and has in turn proven commercial success on a significant scale. This method is still believed to be the best method for manufacturing the metal ball bats with the relatively short tapered sections shown in the drawings of the two aforementioned patents. According to the invention, the bat design is tapered along most of the length of the initial hollow cylindrical work piece, especially in terms of improved possibilities for zero power heating of hard balls. by a combination of machining the surface of the workpiece and then swaging the machined portion of the workpiece to create the desired contour.
It can be improved to function better.

The resulting gradual taper preferably begins relatively close to the handle end of the finished metal body, so that the slugger can use it in a high-throwing professional game, such as in the professional or college games. In the context of baseball, the progressively larger outer diameter of bats will provide increased strength to withstand excessive bending adjacent the pinched portion of the bat. Swenk
ck) U.S. Patent No. 3,691,625, column 3,
As noted in lines 36-37, since there are no internal bores, there is no problem with making the walls too thick at the point where the fuselage taper begins. Therefore, it is now possible to begin tapering the bat as far toward the handle as desired. The wall thickness along the length of the swaged portion of the body can be adjusted by the degree of original machining at each point along the length of the butt, and the adjustment of the brackets is preferably This is done so that the final wall thickness from one end to the other is substantially constant. In summary, according to the invention, a cylindrical hollow metal work piece is first machined and then subjected to a series of quick-cut operations, as detailed in the claims. [a} process, {b-process, (c})
Because the steps are performed sequentially, the walls of the machined work piece can be of varying thickness and the weight balance of the finished bat can be carefully adjusted to give the finished bat the desired strength. Can be done.

The accompanying drawings, which are for illustrative purposes only, depict preferred embodiments of the invention.

Referring now more particularly to the drawings, a metal workpiece, generally designated lo, is shown in FIG. 1 as having a hollow metal body with cylindrical inner and outer surfaces.

The work pieces are generally made of light metals such as aluminum or magnetium and alloys based on any of these. The preferred embodiment of workpiece 10 is an extruded, drawn, and heat treated aluminum alloy. A workpiece piece is first machined into the shape 10a shown in FIG.

This machining involves machining the outside of what will become the handle end of the completed bat to create a cylindrical outer surface 11 extending along the length of work piece 10a, shown as dimension C in FIG. Process it as follows. The opposite end of the work piece 10a, which is to become the striking end of the completed bat, has an unmachined cylindrical outer surface 1 along the length B shown in FIG.
4 is left in place. Plane 2 along length D in FIG.
The intermediate portion of the work piece 10a extending between 0 and 21 is machined on the outside to create a conical outer surface 12, which has an outer diameter equal to the vertical 4 mm of the surface 11. , and the unreduced outer diameter of surface 14. The entire length of the inner surface 16 of the workpiece 10a remains unmachined with the same cylindrical surface 19 that was in the original workpiece 10. Although the taper of surface 12 is described as conical and thus varies in a straight line direction, the machining can also take on any other desired curvature to achieve the ultimate desired purpose. Can be adjusted. After performing the machining described above, the work piece 10a is subjected to an initial swaging operation to form the work piece 10b shown in FIG.

Such swaging operations may be of the conventional type using rotating swaging dies. Conventional swaging dies have a through opening that is relatively 4 mm wide at one end and relatively large at the end, and has a conical or circular opening between the two ends of the opening. The other has a tapered surface. Insert the handle end of the work piece 10a into the large end of the rotating first swaging die, and insert the remaining portion of the work piece 10a into the taper between the large and small end closures of the die. The work piece 10a is moved distally relative to the die until the entire length C and a small portion of the length D completely pass through the small end of the first swaging die. Push it in. This process results in a non-tapered swaging end 26 adjacent the handle end and a tapered swaging portion 1 between planes 28 and 45.
8 is made. The portion of workpiece 10b that has completely passed through the small closure of the first swaging die is shown as dimension E in FIG. 3, and the portion that remains within the tapered portion of the die is shown as dimension E in FIG. It is shown as F. Third
The length F in the figure extends along the remainder of the length O of the work piece 10a shown in FIG. 2 and extends slightly into the unmachined length B shown in FIG. This leaves an unmachined and unswaged surface 22 extending along the length G shown in FIG. 3, ie to the right in this view 45. The inner surface indicated by reference numeral 24 remains cylindrical. The first swaging operation has the effect of forming a cylindrical inner surface along the inside of the length shown in FIG. The walls of workpiece 10b are uniformly thicker than the wall thickness of workpiece 10a along length C shown in FIG. This increase in thickness can be predetermined to offset the reduction in thickness created by the initial machining along length C shown in FIG. 2 to any degree desired. . The portion of length E shown in FIG. 3 that extends into one end of length D shown in FIG. 2 has a wall thickness that is slightly greater than the remaining wall thickness of length E shown in FIG. There is. This is because the effect of the initial machining operation is to increase the thickness of the wall along length D shown in Figure 2 away from the handle end, whereas the effect of the initial swaging operation is to increase the wall thickness along the length D shown in Figure 2 away from the handle end. This is because the effect of thickening the swaging along the orientation length D is gradually reduced. For the portion of the work piece 10b along the length F', the offset effect of the machining operation during the initial swaging operation likewise results in a substantially constant wall thickness along the length F shown in FIG. Alternatively, the wall thickness can be predetermined to increase progressively from left to right in FIG. 3 by predetermined thicknesses of adjacent portions of the batt. If a swaging die of suitable size for one operation can be obtained, the entire swaging operation can be performed in one operation.

However, traditional swaging dies are
have a relatively short length between the ends, typically up to about 33 skins (about 13 inches); this limit, according to the invention, is This can be overcome by the second swaging process. The second swaging die has a diameter smaller than that of the first swaging die and a larger end having a smaller diameter than the larger end of the first swaging die. Workpiece piece 1
The handle end of 0b is pressed against the large aperture of the second swaging die during rotation of the die, and this operation involves inserting the length 1 shown in Figure 4 into the tapered portion of the second swaging die. The process continues along the length marks shown in FIG. 4 until the end of the handle passes through the small weave of the second swaging die. In this way, the second swaging operation creates a non-tapered swaging end 30 and flat surfaces 32 and 2.
A tapered portion 34 extending between 8 and 8 is formed. The second swaging die may have a similar taper as the first swaging die, but preferably
The taper degree is smaller than the swaging die,
This variation of the 7-Pa is very similar to that of traditional wooden baseball bats. The degree of change in taper is in an adjacent contact relationship. The lengths 1 and 1 shown in FIG. 4 both substantially correspond to the length E shown in FIG. The lengths J and K correspond to the lengths F and G shown in FIG. The wall thickness along the lengths 1 and 1 may be predetermined by the initial machining amount balanced against the swaging amount to provide a constant wall thickness along the lengths 1, J and K. , but preferably the length has a constant 4-small wall thickness, which increases along lengths 1 and J until reaching a maximum constant thickness along length K. It is gradually increasing. Both swaging operations are preferably performed without an internal mandrel, in which case the swaging operations tend to thicken the walls without substantially lengthening the workpiece (i.e., approximately 71 skins (28 in.) total). ) about 5 skins of the original length (
(approximately 2 inches) increase).

However, if we take into account that when choosing dimensions zero specified for the various processes, the internal core will limit the wall thickening and increase the lengthening. You could also use money. After the two swaging operations, the workpiece piece 10c shown in FIG. 4 is preferably cut to the desired size at the handle end and the large end is designated 42 as shown in FIG. Machining inside the mind.

The processed end has a "pork shape" and is fitted with an appropriate end screw 40 and fixed in place by a folded portion 44. A handle grip 38 has also been added to complete the bat. Two illustrative examples of baseball bats actually constructed in accordance with the present invention are shown below along with Table 1 and dimensions A to L compiled by Kawako, where: A = original tube, i.e. Second
Total length of the workpiece piece 10a shown in the figure; B=distance in terms of the texture of the finished area from the percussion weave of the workpiece to the end of the machined part (Figure 2); C; = constant outer diameter (c
onsnent0. D. ); D=the distance according to the texture of the machined taper or transition area 12 between planes 21 and 20 in FIG. Certain exterior parts resulting from the swaging work; F = (Fig. 3) Same as "J" (Fig. 4); G = (Fig. 3) Same as "K" (Fig. 4); H = From the handle end of the work piece having a constant diameter (outer diameter), the second
Distance according to the skin display after swaging to the beginning of the transition or tapered part in the plane 32 (FIG. 4) after the second swaging operation; 1=distance according to the skin display after the second swaging operation Length as shown in Figure 4);
J = length of transition after the first swaging operation, that is, the tapered part (Fig. 4) as indicated by the symbol; **K = machining and swaging in the impact-like part of the work piece 10c (Fig. 4) Length of the unmarked portion; L = total length of the finished work piece 10c (Fig. 4) cut to a certain length, as indicated by the skin.

Table 1 [Note] Numbers in parentheses are inches.

Standard bat dimensions A B C L 日・J K D
(佽) C■ ○? ○?
■P ■0 Upward ■Ji
Q earth G's 81.3 (32) 78.7
(31) 10.6 (4 pieces, 6) 3o. u(111 shi 6
) 79.9 (317 thoughts)・2.1 (43 so 4) 83.8
(33) 81.3 (32) lo. 6 (43i6)32.
5 (121 shi 6) 82.4 (327 lives) 146 (5 shi 4
)27.86.4(34)83.8(33)13.1(
5shi, 6) 32.5 (121tsu6) 84.9 (33%6
) 114.6 (5 4) 88.9 (35) 86.4 (3
4) 13.1 (5 6) 35.1 (131, 6) 87
．． 5 (3'・ne6)・7.1ku63re) Table [lQ stroke The numbers in parentheses are inches.

Standard bat dimensions
proboscis 0 proboscis; thingri Gzu ■ ■
81.3 (32) 78.7 (31) 15.7 (6 pieces, 6
) 24-9 (91 shi 6) 79.9 (31 ki 6) 7-o (
2shi 4) 279 (183.8 (33) 81-3 (32)
15.7 (6shi.6) 27.5 (101shi.6) 82-
4 (32%6) 9.5 (3shi486.4 (34) 8
38 (33) 183 (7.6) 27. Desk office 6) 8
4.9 33% 6) 9.5 (33) 27.9 (・1
889 (35) 86.4 (34) 18.3 (7, 6)
3o. qlultsu, 6) 87.5 (34 to 6) 12.1
(43) 27.9 From the preceding example, each bat made by the first and second swaging operations substantially exceeds the approximately 33.0 c twin (13 inch) stroke capacity of the commercially available swaging machine. It can be seen that it has a relatively long taper area of .4 skin (23 inches).

Although the invention has been illustrated and described with respect to the presently preferred embodiment, the description and drawings are for illustrative purposes only and the scope of the invention is not limited except by the claims appended hereto. It will be understood that it is not a thing.

Embodiments of the invention are as follows.

'1} In the manufacturing method described in the claims, the first swaging operation creates a first degree of taper on the outside of the work piece, and the second swaging operation creates a first degree of taper on the outside of the work piece. A manufacturing method characterized by creating a smaller taper on the outside of the contact area.

■ In the manufacturing method described in the claims, the wall thickness is
A manufacturing method characterized by almost uniformity from one end to the edge of the pond.

'3} In the manufacturing method described in the claims, the above 2
A manufacturing method characterized in that the swaging length portion formed by the two supporting tapers is greater than approximately 13 inches.

[Brief explanation of drawings]

Figure 1 is a schematic cross-sectional view of a hollow cylindrical metal work piece, Figure 2 is a cross-sectional view of the work piece in Figure 1 after the outside has been machined over almost its entire length, and Figure 3 is a cross-sectional view of the machined part. FIG. 4 is a schematic cross-sectional view of the work piece shown in FIG. 3 after further swaging,
FIG. 5 is a schematic diagram of a completed baseball bat incorporating the work piece of FIG. 4; FIG. 6 is an enlarged partial front view, partially in section, showing the batting end before the end drill is inserted; and FIG. The figure is a partial front view, partly in section, showing the bat of FIG. 6 after the end screw has been inserted. In addition, in the figure, 10, 10a, 10b, 10c
is a piece of workpiece. Ichikoku EZ, ← Eisei 3. 'D House. 'Saishizan, - Ko5, Eyu?

Claims (1)

[Claims] 1 (a) providing a cylindrical hollow metal workpiece; and (b) machining substantially the entire length of the outside of said workpiece to reduce the wall thickness of said workpiece to a predetermined range. (c) shaping said workpiece so that a majority of the machined portion of said workpiece is swaged in successive swaging operations to form two abutting tapers; and The wall thickness of the work piece is increased to a predetermined range thinned by machining, and the machining and swaging effects result in a tapered section having a predetermined wall thickness from one end to the other. A process for making a metal bat body, and a method for manufacturing a metal body for a ball bat.