In light of the shortcomings of the prior art, it is an
SOFTBALL BAT objective of the present invention to provide an improved bat.
This application is a continuation of application Ser. It is another objective of this invention to provide a
No. 08/062,307, abandoned, filed on May 14, 1993. 5 bat that increases the power transferred from the bat to
a batted ball.
FIELD OF THE INVENTION It is yet anotner objective of this invention to provide The present invention relates to Softball and baseball a simple construction for a tubular bat with an insert, bats and more particularly relates to the use of struc- In accordance with a preferred embodiment of the tural members inside such bats to improve their impact 10 present invention, a tubular aluminum bat frame is proresponse, vided with a large-diameter impact portion, an intermediate tapering portion, and a small-diameter handle BACKGROUND AND SUMMARY OF THE portion. A tubular insert is suspended within the impact INVENTION portion by interference fits at each insert end. A first Tubular metallic Softball (and baseball) bats are well 15 interference fit is achieved by forcing the first end of the known in the art. A familiar example is a tubular alumi- insert mt0 the tapering portion of the bat frame. The num bat. Such bats have the advantage of a generally second interference-fit is then formed by curling the end good impact response, meaning that the bat effectively of the impact portion over upon the second end of the transfers power to a batted ball. This effective power msert A SaP exists alom? the leaS& of the suspended transfer results in ball players achieving good "slug- 20 msert separating the insert from the interior of the imging" distances with batted balls. An additional advan- Pact portion. The gap is filled with grease to facilitate tage of such aluminum bats is the improved durability TMve movement between the msert and the tubular over crack-prone wooden bats. frame when a ball ,s batted.
Even though today's aluminum bats perform well, 11?e foregomg and additional features and advantages there is an ever-continuing quest for bats with a better 25 °f the mventI°n will be more readily apparent "slugging" capacity. Accordingly, one important need from ^following detailed description, which prois to optimize the impact response of a bat. Generally ceeds wlth reference t0 the accompanying drawings, speaking, impact response is best when a bat undergoes BRIEF DESCRIPTION OF THE DRAWINGS
a greatest elastic deflection, before rebounding with a , , , . ^, , it_ .
^ *r ■ I. 1 ^?*4 - 30 FIG. 1 shows a sectional view through the center of
greatest force m the shortest amount of time. Optimiza- „ , . . , ... & ^ . . .
• tli f ^ • vu « • » t a Softball bat in accordance with one aspect of this
tion of these three factors increases the spring" of a . m .- y
, „ _. , . ,,. , ., . f e> mvention.
ball off a bat, yielding a bat with a superior power trans- FIQ 2 ig a ified cut yigw of the bat f FIG
fer and faculty for slugging. j
Constraining the design of aluminum bats is the re- 35 'FIQ 3 is a ... view ^ ^ ^ 3_3 Qf quirement that the elastic deflection not be accompa- -p\Q 2 nied by any plastic deformation. Plastic deflection lessens the power transfer to a ball and leaves the bat per- DETAILED DESCRIPTION manently dented. Thus, aluminum bat design is driven Referring to FIG. 1, a Softball bat 10, according to by the elastic and plastic deformation characteristics of 40 one embodiment of the present invention, has a tubular aluminum. For example, when the tubular wall is too aluminum frame 11 with a relatively large-diameter thin, a desirable large amount of elastic deflection is impact portion 12, an intermediate tapering portion 14, achieved, but with unwanted permanent plastic defor- and a relatively small-diameter handle portion 16. mation. On the other hand, when the aluminum tubular To provi(}e for an improved impact response yielding wall is too thick, the bat may be too stiff to elastically 45 a better transfer of power from the bat to a batted ball, deflect appreciably. In this case, the bat responds with a tubular insert 18 is suspended within the impact porrelatively little spring, resulting in lower power trans- tion 12 of the tubular frame. The tubular insert is a fer- hollow tube of an outer diameter slightly less than the
To provide for greater "spring," tubular bats using inner diameter of the tubular frame impact portion 12. other materials, such as titanium, have been developed. 50 A first end 20 of the tubular insert 18 is inserted through
Titanium is a high-strength material permitting thin bat the impact portion 12 to be forcefully lodged in abut
frame walls which provide a substantial elastic deflec- ment with the diametrically narrowing interior wall of
tion without plastic deformation. Such bats provide the tapering portion 14, thus forming a first interference
excellent spring-like response and power transfer to a fit. A second end 22 of the tubular insert 18 is spaced batted ball. However, the material cost and difficulty of 55 inwardly from the top end of the impact portion 12
working titanium result in a high consumer cost. when the tubular insert 18 is secured in the first interfer
The prior art also includes tubular bats using inserts. ence fit. A second interference fit is created at the insert
While most often inserts are used for vibration deaden- second end 22 by curling the topmost portion of the
ing purposes, U.S. Pat. No. 3,963,239 of Fujii discloses impact portion over upon the insert second end 22. The a metallic bat frame with a large-diameter impact por- 60 curled-over portion forms a reduced-diameter head
tion receiving an insert to adjust the weight and im- portion 24 of the tubular frame 11.
prove the "repelling action" of the bat. Fujii teaches an Because the outer diameter of the insert 18 is slightly
insert in tight abutment within the tubular frame, so that less than the inner diameter of the tubular frame impact
the insert is fixed relative to the frame. The engagement portion 12, the suspended insert 18 contacts the tubular is improved by forcing the insert into the tapered inter- 65 frame only at the interference fits of the first and second
mediate portion of the bat and/or by gluing the insert insert ends 20, 22. A narrow, uniform gap 26 exists
within the frame. The tightly-fitted Fujii insert simply between the insert 18 and the inner wall of the impact
acts to thicken the wall of the impact portion of the bat. portion 12. The gap extends uniformly around the insert