U.S. patent application number 09/175339 was filed with the patent office on 2001-08-16 for metal baseball bat with wood bat performance characteristics.
Invention is credited to MACKAY,, JACK W. III.
Application Number | 20010014634 09/175339 |
Document ID | / |
Family ID | 22639911 |
Filed Date | 2001-08-16 |
United States Patent
Application |
20010014634 |
Kind Code |
A1 |
MACKAY,, JACK W. III |
August 16, 2001 |
METAL BASEBALL BAT WITH WOOD BAT PERFORMANCE CHARACTERISTICS
Abstract
A metal bat in which the performance characteristics of an
impact of the metal bat with a baseball are the same as or
substantially the same as the performance characteristics of a wood
bat impacting a baseball. The construction of the metal bat dampens
the resilience of the metal bat barrel and reduces the trampoline
effect of the bat when impacting the baseball to reduce the exit
velocity of the baseball at impact. In addition, the bat speed at
the point of impact with a baseball can be decreased by increasing
the weight of the bat, preferably at its outer end and adjusting
the balance point of the bat toward the outer end.
Inventors: |
MACKAY,, JACK W. III; (MT.
PLEASANT, TX) |
Correspondence
Address: |
HARVEY B JACOBSON JR
JACOBSON PRICE HOLMAN & STERN
400 7TH STREET NW
WASHINGTON
DC
20004
|
Family ID: |
22639911 |
Appl. No.: |
09/175339 |
Filed: |
October 20, 1998 |
Current U.S.
Class: |
473/566 |
Current CPC
Class: |
A63B 59/51 20151001;
A63B 2102/18 20151001; A63B 59/50 20151001 |
Class at
Publication: |
473/566 |
International
Class: |
A63B 059/06 |
Claims
What is claimed as new is as follows:
1. A metal baseball bat comprising a hollow metal bat barrel
tapering from an outer bat barrel end to a reduced diameter handle
at a knob end, a closure for the outer bat barrel end of said
barrel, said hollow metal bat barrel having a generally cylindrical
barrel wall defining an interior barrel surface, said bat barrel
wall having a resistance to deformation and a resistance to
trampoline effect upon ball impact, and mechanical means in direct
contact with said interior wall surface to increase said resistance
to deformation and decrease said trampoline effect of said bat
barrel when impacted by a baseball.
2. The metal bat as defined in claim 1, wherein the increase in
said resistance to deformation and decrease in said trampoline
effect of said bat barrel reduces the velocity of a baseball
impacted by said baseball bat.
3. The metal baseball bat as defined in claim 1, wherein said
mechanical means reduces the ball exit velocity of a baseball
impacted by said metal bat to 90-98 mph when said bat is moving at
72 mph and said ball is moving at 72 mph.
4. The metal baseball bat as defined in claim 3, wherein said ball
exit velocity is about 93 mph.
5. The metal baseball bat as defined in claim 1, wherein said outer
bat barrel end includes weight material shifting the balance point
of said metal baseball bat to about 65% of the length of the bat
from said knob end.
6. The metal bat as defined in claim 1, wherein said means
comprises a plurality of foam plastic blocks forced into an open
end of the bat barrel to completely fill the bat barrel and resist
inward deformation of the bat barrel wall when impacted with a
baseball thereby reducing the trampoline effect of the bat barrel
wall and reducing exit velocity of a baseball impacted by the wall
of the bat barrel.
7. The metal bat as defined in claim 1, wherein said means
comprises an expanded plastic foam material substantially
completely filling the bat barrel, said plastic being foamed in
situ and resisting deformation of the bat barrel wall when
impacting a baseball to obtain an exit velocity of a baseball
impacted by the metal bat barrel to a speed substantially equal to
the exit speed of a baseball impacted by a wood bat.
8. The metal bat as defined in claim 1, wherein said means
comprises an inflated bladder extending substantially throughout
the length of the bat barrel and engaging the internal surface
thereof to reduce inward deformation of the bat barrel upon impact
with a baseball thereby reducing the trampoline effect.
9. The metal bat as defined in claim 1, wherein said closure for
the outer end of the bat barrel includes a weight to provide a
length to weight ratio in which the weight in ounces without grip
is at least three less than the length in inches to shift the
balance point of the bat to a position on the metal bat barrel to
substantially coincide with the position of the center of gravity
of a wood bat.
10. The metal bat as defined in claim 9, wherein said closure for
the outer end of the bat barrel includes an end cap having a
cylindrical portion telescoped into the end of the bat barrel, said
bat barrel and cylindrical portion of the end cap including a rib
and groove engaging surfaces, said cylindrical portion of the end
cap defining a cavity filled with an added weight to locate the
balance point of the metal bat to a position on the bat barrel more
than 21 inches from the end of knob.
11. The metal bat as defined in claim 6, wherein said closure for
the outer end of the bat barrel includes an inturned end on the bat
barrel terminating in an opening in the outer end of the bat
barrel, a closure plug of resilient material closing the opening
end extending peripherally of the end turned end of the bat barrel,
said enclosure plug being constructed of weighted material to
position the balance point on the metal bat barrel in substantially
the same position as a balance point on a wood bat barrel.
12. A metal baseball bat comprising a hollow metal bat barrel
tapering from an outer bat barrel end to a reduced diameter handle
at a knob end, a closure for the outer bat barrel end of said
barrel, said outer metal bat barrel having a generally cylindrical
barrel wall and defining a ball hitting zone, said cylindrical
barrel wall uniformly thickened in said ball hitting zone by about
0.005 inches to about 0.120 inches in order to resist deformation
and trampoline effect of said bat barrel wall upon ball impact,
said bat having an adjusted balance point more than about 21 inches
from said knob end.
13. The metal bat as defined in claim 12, and further including a
mechanical means in direct contact with an interior surface of said
bat barrel in said hitting zone to further increase said resistance
to deformation and trampoline effect.
14. The metal bat as defined in claim 13, wherein said wall
thickness and said mechanical means reduce the ball exit velocity
of a baseball impacted by said metal bat to 90-98 mph when said bat
is moving at 72 mph and said ball is moving at 72 mph.
15. The metal bat as defined in claim 14, wherein said ball exit
velocity is about 93 mph.
16. The metal bat as defined in claim 12, wherein said hollow metal
bat barrel has a barrel wall uniformly thickened throughout its
length.
17. The metal bat as defined in claim 13, wherein said mechanical
means comprises a plurality of foam plastic blocks forced into an
open end of the bat barrel to completely fill the bat barrel and
resist inward deformation of the bat barrel wall when impacted with
a baseball thereby reducing the trampoline effect of the bat barrel
wall and reducing exit velocity of a baseball impacted by the wall
of the bat barrel.
18. The metal bat as defined in claim 13, wherein said mechanical
means comprises an expanded plastic foam material substantially
completely filling the bat barrel, said plastic being foamed in
situ and resisting deformation of the bat barrel wall when
impacting a baseball to obtain an exit velocity of a baseball
impacted by the metal bat barrel to a speed substantially equal to
the exit speed of a baseball impacted by a wood bat.
19. The metal bat as defined in claim 13, wherein said mechanical
means comprises an inflated bladder extending substantially
throughout the length of the bat barrel and engaging the internal
surface thereof to reduce inward deformation of the bat barrel upon
impact with a baseball thereby reducing the trampoline effect.
20. The metal bat as defined in claim 1, wherein the length of the
bat in inches is not more than 3 units greater than the weight of
the bat in ounces, without a grip wrap, said bat barrel having a
diameter no greater than 2.625 inches, and said bat having a
balance point at least 21.5 inches from said knob end and the ball
exit velocity under a 72.times.72 test no greater than 93.+-.1
mph.
21. A method for custom designing a metal bat to have performance
characteristics closer to a wood bat, said bat having a hollow
metal bat barrel tapering from an outer bat barrel end to a reduced
diameter handle at a knob end, said outer metal bat barrel having a
generally cylindrical barrel wall and defining a ball hitting zone,
which comprises selecting said hollow metal bat barrel to have a
length in inches no more than 3 units greater than a weight in
ounces of said bat and being no greater than 2.625 inches in
diameter throughout its length, dampening said generally
cylindrical barrel wall in said ball hitting zone to increase
resistance to deformation and decrease trampoline effect of said
barrel wall and adjusting the center of gravity away from said knob
end at least about 21.5 inches from said knob end.
22. The method of claim 21, wherein said dampening reduces the ball
exit velocity of a baseball impacted by said metal bat to 90-98 mph
when said bat is moving at 72 mph and said ball is moving at 72
mph.
23. The metal baseball bat as defined in claim 1, wherein said
mechanical means comprises a sleeve which cooperates with said bat
barrel wall to increase said resistance to deformation and decrease
said trampoline effect.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to developments in baseball
bats and more particularly to the construction of a metal baseball
bat in which the impact with a baseball is the same as or closer to
the ball exit velocity of a wood baseball bat impacting a baseball.
The construction of the metal baseball bat of this invention
dampens or reduces the trampoline effect of the bat when impacting
the baseball and/or decreases bat speed at the point of impact with
a baseball by custom designing the bat to impart a prescribed ball
exit velocity at impact.
[0003] 2. Description of the Prior Art
[0004] Metal baseball bats have been used extensively in lieu of
wood bats in view of the many advantages that a metal bat has as
compared to a wood bat. While wood bats are used exclusively in
most professional baseball leagues, hollow metal bats have been
accepted for use in various nonprofessional baseball leagues,
organizations and the like. Metal bats have been used for a number
of years by college teams, high school teams, little league teams
and various other subprofessional baseball teams.
[0005] In recent developments, metal baseball bats have been
provided with improved structural details which have resulted in
substantially increased exit velocity of the baseball from the
baseball bat upon impacting a pitched baseball with a metal bat.
These developments in improving the performance of metal baseball
bats have included, for example, reducing the weight of the bat,
increasing the diameter of the bat barrel to 2.750 inches in
outside diameter, and increasing the trampoline effect by changing
the wall thickness and utilizing different materials and placing
inserts in the hollow interior. These improvements have resulted in
the batted ball traveling at a higher exit velocity and in a longer
distance of flight after leaving the bat.
[0006] As a result of the higher exit velocity of the baseball when
impacted by a metal bat, the pitcher and fielders have less time to
react to the trajectory of the baseball. Pitchers are extremely
vulnerable to being hit by a high exit velocity baseball impacted
by a metal bat inasmuch as the pitcher is only about sixty feet
away from the batter and possibly less than sixty feet depending
upon the characteristics of the pitching motion and follow through
when delivering a pitch to the batter. The higher exit velocity of
the baseball when struck by a metal bat subjects the pitcher to
possible injury since the higher exit speed and velocity of the
batted ball reduces the time in which a pitcher can react to place
the glove in a defensive position in the path of movement of the
baseball. Other infielders are similarly subject to the possible
dangers of baseballs hit at high exit velocities.
[0007] The following U.S. patents relate to developments in
baseball bat constructions:
1 3,727,295 5,393,055 5.460,369 5,114,144 5,395,108 5,494,280
5,217,221 5,421,572 5,511,787 5,338,024 5,458,330 5,533,723
[0008] U.S. Pat. Nos. 5,421,572, 5,494,280 and 5,393,055 disclose
some of the baseball bat structures that have been developed to
enhance impact with the baseball including construction of the bat
having a maximum diameter of 2.750 inches and unique end caps and
weight loads. U.S. Pat. No. 5,114,144 and others disclose a
composite baseball bat including a central core having an outer
layer of wood veneer impregnated with a resin retaining the core
and veneer in assembled relation.
[0009] While hollow metal bats of aluminum and various other metals
and metal alloys are well known and composite bats with a core and
external wood veneer are well known as are larger diameter bat
barrels, the prior art does not disclose a metal baseball bat which
is custom designed to have wood bat performance characteristics,
particularly one providing the same or closer to the same ball exit
velocity as a wood bat in accordance with the present
invention.
SUMMARY OF THE INVENTION
[0010] In recognition of the potential for injury due to recent
developments in metal baseball bats and the tendency for increased
hits and runs occurring, regulatory agencies which formulate rules
of play have become increasingly concerned about the potential of
injury arising from use of high performance metal baseball bats.
The regulatory agencies have also expressed the desire to return
the incidence of hits, home runs and the like in baseball to a more
competitive status resulting from less baseball games in which a
high number of runs are scored. The regulatory agencies also desire
to make the game of baseball as safe as possible for the
players.
[0011] Accordingly, it is the object of the present invention to
construct a metal baseball bat which has structural characteristics
to impact the baseball closer to the performance characteristics of
a wood bat. In testing high quality wood bats with comparable metal
bats, it was surprisingly found that a metal bat with appropriate
modifications could be made to have the same, or closer to the
same, performance characteristics as a wood bat. When tested on a
dynamic hitting machine, such as the Baum bat testing machine, it
was discovered that a metal bat swung at 72 miles per hour (mph) at
the 5 inch point measured from the barrel end to impact a baseball
also traveling at the same 72 mph speed should produce a ball exit
velocity of 90-94 mph, or preferably 93 mph.+-.1 mph. At such ball
exit velocity, the metal baseball bat exhibits the same or closer
to the same performance characteristics as a baseball bat made from
high quality wood. Therefore, the metal baseball bat of the present
invention should be adjusted to produce a ball exit velocity,
preferably, of 90-94 mph. However, under certain circumstances, the
metal baseball bat of this invention can be adjusted to produce a
ball exit velocity as high as 98 mph.
[0012] To test a metal baseball bat on a dynamic hitting machine in
accordance with this invention, the input target speeds for bat
swing speed and for ball speed are each set at 72 mph, with a 1 mph
deviance for test variance. Raw data exit velocities are recorded
at four (4) impact test locations on the bat (measured from the
barrel end) at 4 inches, 5 inches, 6 inches and 7 inches. Five exit
velocity readings at triangle-node sights (three equidistant
locations around the circumferences of the bat) are to be recorded
at each of the four impact locations. The Wilson A1001NCWA
Championship baseball and/or the Diamond D1 Collegiate baseball
should be used for the test. The ball shall have a maximum weight
of 5.10.+-.0.05 ounces. The maximum circumference of the ball shall
be 9.25.+-.0.10 inches. The coefficient of restitution shall be
between 0.525 and 0.555 and conducted to ASTM specifications.
Before the testing procedure, the baseballs should be stored for 48
hours at a room temperature of 75.degree..+-.30.degree. F. and a
relative humidity of 65.+-.5%. The testing on the dynamic hitting
machine should be conducted in a testing lab or room also
maintained at a temperature of 75.degree..+-.30.degree. F. and a
relative humidity of 65.+-.5%. The ball exit velocity must match
the designated velocity in mph, with a 1 mph deviation for test
variance, at each of the four impact locations.
[0013] Hence, at the preferred 93 mph ball exit velocity, the ball
exit velocity of the metal baseball bat under test must not exceed
93.+-.1 mph at any of the four impact locations, i.e. cannot exceed
a maximum of 94 mph. The foregoing test procedures are hereinafter
referred to as the "72.times.72 test".
[0014] In order to achieve a metal baseball bat which will produce
the requisite ball exit velocity of 90-98 mph in the 72.times.72
test, it was discovered that the metal bat barrel should preferably
be dampened. Therefore, in accordance with the present invention,
such dampening can be accomplished by a number of ways to achieve a
90-98 mph, preferably a 93.+-.1 mph, ball exit velocity under the
72.times.72 test, including without limitation, filling the
interior of the metal baseball bat barrel with pieces of
compressible "styrofoam" expanded plastic or rubber material in the
form of blocks or balls or with an expanding foam material or with
an inflatable bladder or by thickening the bat barrel wall or by
lining the interior of the barrel wall with a mechanical device
such as a sleeve or metal spiral or the like.
[0015] Further, in accordance with the present invention, the bat
barrel size of the metal baseball bat is reduced to a maximum of
2.625 inches in order to correspond to wood bats, which size
reduction also results in a reduction of high exit speed baseballs
hit by the bat.
[0016] In addition, in order to provide a metal baseball bat having
wood bat performance characteristics, the metal baseball bat
according to the present invention has a minimum weight in ounces
that is approximately three less than the length of the bat in
inches; for example, a 33 inch length bat will have a weight of at
least approximately 30 ounces. This weight is without the handle
grip wrap.
[0017] Furthermore, it has been discovered that a metal baseball
bat can approximate the performance characteristics of a high
quality wood bat if the weight and balance point of the bat are
moved forward away from the handle in order to decrease the bat
speed. The present invention preferably moves this balance point to
at least approximately 21 1/2 inches from the end of the knob end
of the bat.
[0018] It is, therefore, a further object of this invention to
provide a metal baseball bat in which the trampoline effect is
reduced by varying the wall thickness of the hollow bat, filling
the bat barrel with blocks of "Styrofoam" expanded plastic material
or expanded foam material or positioning an internal inflatable
bladder in the hollow bat barrel or by lining the interior of the
barrel wall with a mechanical device or sleeve.
[0019] Still another object of the invention is to construct a
metal bat having wood bat performance characteristics in which the
weight and balance point of the bat are varied to decrease the bat
speed and thus the exit velocity of a baseball when impacted with
the bat.
[0020] Thus, the metal bat of this invention reduces the exit
velocity of a batted ball to preferably about 93 mph under the
72.times.72 test, but in the range of 90-98 mph. This ball exit
velocity compares with existing metal bats in which the exit speeds
are frequently approximately 105 mph or more. This reduction in
exit velocity provides additional time for the pitcher and other
fielders to react and move his/her glove to a defensive
position.
[0021] These together with other objects and advantages which will
become subsequently apparent reside in the details of construction
and operation as more fully hereinafter described and claimed,
reference being had to the accompanying drawings forming apart
hereof, wherein like numerals refer to like parts throughout.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a side elevational view of a metal baseball bat
constructed in accordance with the present invention.
[0023] FIG. 2 is a schematic plan view of the bat illustrating the
impact with a baseball and the balance points of a wood baseball
bat, a conventional metal baseball bat and a metal baseball bat
constructed in accordance with the present invention.
[0024] FIG. 3 is a schematic plan view of a metal baseball bat
constructed in accordance with the present invention illustrating
the effect of added weight to the rotational speed of the bat.
[0025] FIG. 4 is a fragmented sectional view of the end of the bat
barrel of a metal bat constructed in accordance with the present
invention illustrating an end cap with added weight incorporated
therein.
[0026] FIG. 5 is a sectional view of the hollow bat barrel of a
metal bat constructed in accordance with the present invention
illustrating an inflated bladder extending throughout at least the
approximate length of the bat barrel.
[0027] FIG. 6 is a sectional view of the hollow bat barrel of a
metal bat constructed in accordance with the present invention in
which a plurality of "Styrofoam" blocks fill the interior of the
bat at least throughout the approximate length of the bat
barrel.
[0028] FIG. 7 is a sectional view similar to FIG. 6 illustrating a
foam plastic material foamed in situ or otherwise placed within at
least the approximate length of the bat barrel.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Although several preferred embodiments of the invention are
explained in detail, it is to be understood that the invention is
not limited in its scope to the details of construction and
arrangement of components set forth in the following description or
illustrated in the drawings. The invention is capable of other
embodiments and of being practiced or carried out in various ways.
Also, in describing the preferred embodiments, specific terminology
will be resorted to for the sake of clarity. It is to be understood
that each specific term includes all technical equivalents which
operate in a similar manner to accomplish a similar purpose.
[0030] The metal baseball bat of the present invention is
illustrated in FIG. 1 of the drawings and is generally designated
by reference numeral 10. Bat 10 includes a hollow tubular metal bat
barrel 12, a handle or hand grip area 14 with a spiral wrapping
thereon and a knob 16 on the handle end of the bat. The barrel end
17 of the bat 10 is preferably provided with an end cap 18. This
basic structure is that which is found in conventional and existing
metal baseball bats.
[0031] One of the structural features of the metal baseball bat 10
of this invention is the reduction in diameter of the bat barrel 12
to a maximum of 2.625 inches to conform to the diameter of the
larger wood bats. This reduction in bat barrel size from a previous
maximum of 2.750 inches reduces the diameter of the hitting area of
the bat and decreases the number of baseballs that are effectively
hit by the bat.
[0032] FIG. 2 is a schematic illustration of a typical baseball bat
illustrating a baseball 20 impacted by the bat with the ball 20
moving in a trajectory indicated by arrow 22. The balance point of
a conventional metal bat is designated by reference numeral 24. The
balance point of a conventional wood bat is designated by reference
numeral 26. The balance point of the metal bat of the present
invention is designated by reference numeral 28 which is closer to
the balance point 26 of a wood bat. As indicated, the balance point
of the metal baseball bat of this invention is closer to the end
cap and spaced further from the knob 16 as compared to the balance
point 24 of a conventional metal baseball bat. More specifically,
it has been found that a balance point for a metal baseball bat
which is at least about 21 1/2 inches from the knob end of the bat
provides performance characteristics more like a wood bat. Further,
in accordance with this invention, the balance point can be custom
designed in the metal bat between about 20 1/2 to about 22 1/2
inches from the knob end of the bat. Thus, with the balance point
28 being further from the handle 14 and knob 16, a batter 30 will
have a slower bat speed in view of the increase in the lever arm
between the balance point 28 and the hands 32 gripping the handle
14, assuming no change in the weight of the bat.
[0033] FIG. 3 is another schematic illustration of the metal
baseball bat of the present invention in which arrow 34 indicates a
weight oriented toward the end of the bat barrel 38 with the ball
being designated by reference numeral 40 and the trajectory being
designated by reference numeral 42. The weight added toward the end
of the bat barrel results in a slower bat speed inasmuch as the
batter 44 must exert additional force on the handle 14 in order to
swing the bat barrel at a predetermined bat speed. This compares to
conventional metal bats which have a lighter weight for a given
length, for example, a 33 inch bat having a total weight of 28
ounces. In accordance with the present invention, the metal
baseball bat must have a weight in ounces of only approximately
three less than the length of the bat in inches. For example, a 33
inch bat must have a weight of at least about 30 ounces without
grip. The end cap 36 can have weight added if necessary to move the
balance point toward the barrel end 17 of the bat.
[0034] FIG. 4 is a fragmental sectional view of a hollow bat barrel
50 having an end cap 52 mounted thereon in a manner disclosed in
the prior art. The end cap 52 includes a cylindrical extension 54
having a groove 56 therein which receives an internal rib 58 formed
in the inner surface of the end of the bat barrel 50. The inner
surface of the bat barrel 50 also includes a shallow groove 60
receiving a reduced diameter portion 62 of the cylindrical sleeve.
This structure is a well known end cap and bat barrel construction.
Also, the interior of the end cap 52 includes a plurality of a
radially extending reinforcements 64 having concavely curved inner
edges 66, also as known in the prior art.
[0035] An additional weight 68 of dense material such as
polyurethane or the like fills the interior void space of the end
cap 52 and projects slightly beyond the inner end of the
cylindrical extension 54 on the end cap. The actual volume and
weight of the added weight material 68 may vary to provide a
desirable shift in the balance point of the hollow metal bat and
also to adjust the actual total weight of the bat and bat barrel.
The change in the balance point to move it outwardly from the
handle of the bat increases the force necessary to propel the bat
barrel at a predetermined bat speed. Likewise, the added total
weight at the end of the bat barrel also requires additional force
to propel the bat barrel at a predetermined bat speed. Thus, the
addition of an added weight 68 to the interior of the end cap or to
the interior of the end of the bat barrel results in a slower bat
speed as compared to conventional metal bats which include an end
cap but do not include additional weight. The configuration of the
end cap and the manner of connecting the end cap to the end of the
bat barrel may vary depending on the choice of the manufacturer.
Further, the weighted material 68 can extend into and engage the
inner surface 63 of the bat barrel 50 so as to assist in holding
the end cap 52 in place. The added weight material 68 may also vary
as to density and total weight in order to obtain the desired
maximum bat speed. More specifically, the weighting and balance
point will result in a reduced exit velocity of a baseball when
impacted by the metal bat of the present invention so that the exit
velocity of the baseball will be 90-98 mph, preferably 93.+-.1 mph,
when tested in the 72.times.72 test.
[0036] FIG. 5 illustrates a hollow metal bat barrel which includes
an end cap 72 having an added weight 74 incorporated therein in the
same manner as disclosed in FIG. 4. Positioned internally of the
bat barrel is an inflated bladder 76 of resilient flexible material
having an inflation valve or other device 78 adjacent the end cap.
The bladder 76 directly engages the internal surface of the bat
barrel from the end cap down towards the handle of the bat and
extends at least throughout the length of the bat barrel. When the
bladder is inflated to relatively low pressures, it will exert a
force radially outwardly in relation to the wall of the bat barrel
which tends to resist inward deformation of the wall of the bat
barrel when the bat is impacted with a baseball. This is in
contrast to current high performance inflated bladder bats where
the internal bladder is under relatively high pressure, and the
bladder in effect increases the trampoline effect of the metal bat
barrel wall. It has been found that bladders inflated to pressures
up to only about 15 pounds per square inch (above atmospheric
pressure) (psi) will increase the resistance to inward deformation
of the wall of the bat barrel by an impact with a baseball, thus
causing a dampening of the trampoline effect. Preferably, the
internal bladder should be pressurized to 8-15 psi. obviously, any
known bladder design, construction and inflating gas could be used
in accordance with this invention, as well as a plurality of
bladders laid end-to-end, or even side-by-side.
[0037] The forces exerted on a baseball when impacted by a metal
bat in accordance with the construction illustrated in FIG. 5
reduces the exit velocity of the baseball so that it does not
exceed 94 mph, when tested under the 72.times.72 test.
[0038] The inflated bladder 76 as illustrated in FIG. 5 may be used
with an end cap having an added weight or an end cap having no
added weight. Also, the configuration and manner of mounting the
end cap may vary as well as the pressure inside the bladder, as
both previously described. The bladder, when used with a
conventional end cap without added weight, reduces the exit
velocity of an impacted baseball by reducing the trampoline effect.
When an end cap with an added weight is utilized with the internal
bladder, the added weight, the changes in the balance point and the
reduction in trampoline effect are combined to reduce exit velocity
of a baseball impacted by the bat to the prescribed exit
velocity.
[0039] FIG. 6 illustrates a bat barrel 80 having a conventional end
cap 82 which closes off the bat barrel end 84. A hardenable
material 86 fills the end cap 82 and the end of the bat barrel
opening 84. The closure material thus forms a weighted end of
polyurethane or other weighted material and the volume, and thus
the weight, of the material 86 may be varied. FIG. 6 illustrates
inserted material 88 filling the bat barrel 80 from the closure
material 86 to the handle area and at least throughout the length
of the bat barrel. The inserted material 88 is preferably in the
form of a plurality of blocks or balls of expanded foam plastic or
foam rubber material, such as "Styrofoam", which is either in a
sponge-like or rigid form and can be shoved inwardly from the open
end of the bat barrel before final closure of the end of the bat
barrel with end cap 82. The blocks of foam plastic or other
material are compressed axially inwardly directly against the
interior surface of the bat, and exert an outward force on the
interior surface of the bat barrel wall. This outward force
functions to resist inward deformation on the wall of the bat
barrel, thereby reducing the trampoline effect of the bat barrel
wall, when impacting a baseball.
[0040] The number, density and rigidity of the foam blocks, or
balls, and the outward force exerted on the barrel wall when the
blocks or balls are in place within the bat barrel 80 may be varied
as well as the weight and volume of the closure material 86. This
enables the exit velocity of an impacted baseball to be reduced by
both reducing the trampoline effect and adjusting the weight of the
end closure plug. Adjusting the weight of weighted material 86 also
changes the balance point so that it closely simulates the balance
point of a wood bat and also increases the overall weight of the
bat so that the difference between the length of the bat in inches
and the weight of the bat in ounces is not more than three. As with
the embodiment shown in FIG. 5, the plastic material 88 can be used
with or without the weighted material 86, and any end cap
configuration is acceptable so long as the requisite ball exit
velocity is designed into the metal bat.
[0041] FIG. 7 illustrates a bat barrel 90 having a slightly
different but known barrel end structure. The barrel has an
inturned end 92 which defines a central opening 94. A closure
material 96 in the form of a closure plug is provided for closing
the opening 94 with the closure material 96 being varied in volume
and weight to obtain a desired weight to length ratio for the bat.
The interior of the bat barrel is provided with an expanded plastic
material 98 which is in direct contact with the interior wall of
the bat barrel and is expanded in situ to fill the interior of the
bat at least throughout the length of the bat barrel. The expanded
plastic material will resist inward deformation of the bat wall
thereby reducing the trampoline effect in a manner similar to the
structures illustrated in FIGS. 5 and 6. The resistance to
deformation of a bat barrel wall reduces the trampoline effect
caused by a return of the deformed bat barrel wall to its original
position thereby reducing the exit velocity of a baseball impacted
by the bat barrel 90. This construction enables the bat speed to be
controlled by adjusting the volume and weight of the closure plug
and by using the foamed in situ expanded plastic material 98 to
adjust the weight and balance point of the bat and to reduce the
trampoline effect by resisting deformation of the bat barrel
wall.
[0042] The metal bat barrel of the present invention can be made
from any conventional metal baseball bat material, such as aluminum
and aluminum alloys, titanium and titanium alloys, or any other
material that will provide a solid bat barrel wall and can be made
to the total weight of three ounces less than the length in inches
of the bat, without the grip wrap, and with a balance point more
than about 21 inches from the knob end, and can produce a ball exit
velocity of 90-98 mph under the 72.times.72 test.
[0043] The wall thickness of the metal bat barrel of the present
invention may also be uniformly thickened in order to dampen the
trampoline effect of the bat barrel wall. More specifically,
current standards for wall thickness of metal baseball bats vary
the wall thickness from 0.80 to 0.120 inches. In accordance with
this invention, the wall thickness of the bat barrel can be
increased by about 0.005 inches to about 0.120 inches in order to
achieve the dampening characteristics of the present invention.
While it is preferable to increase the wall thickness throughout
the length of the bat, from the top of the knob 16 to the open end
17, the thickness can be confined to the hitting area of the bat,
i.e. from the top of the transition zone to the open end 17.
[0044] Further, an increase in the wall thickness can be combined
with other mechanisms for dampening the metal bat barrel and its
trampoline effect, such as by filling the interior of the bat
barrel with compressible blocks or balls, with an expanding foam
material or with an inflatable bladder, as disclosed in this
application. The resultant effect, of course, is to custom design
the metal baseball bat to produce the requisite ball exit velocity
of 90-94 mph under the 72.times.72 test and which exhibits
performance characteristics which are the same as or closer to the
performance characteristics of a baseball bat made from high
quality wood.
[0045] The bat barrel diameter in accordance with the present
invention is a maximum of 2.625 inches but may be smaller, such as
2.400 inches. Wall thickness of the bat should be a maximum of
0.160 inches and at or above 0.115 inches. In 72.times.72 tests
comparing the metal bat of this invention with conventional wood
bats, a metal bat constructed and in accordance with the present
invention obtained approximately the same exit velocity for the
baseball as the wood bat. In effect, the metal bat of this
invention reduced the ball exit speed and reduced the trampoline
effect of the bat barrel wall. One prototype metal bat that tested
to the above performance characteristics was constructed of CU 31
alloy. The prototype bat included an external major diameter of
2.625 inches, a length of about 33 inches, a weight of about 30
ounces, a wall thickness of about 0.120 inches, a balance point of
about 21.25 inches from the knob end. This bat was comparatively
tested with a conventional wood bat having the same dimensions and
an existing aluminum bat having a 2.750 diameter, a 33 to 28
length/weight ratio and a balance point of 20.625 inches from the
knob end. The metal bat constructed in accordance with the present
invention resulted in an exit velocity of an impacted baseball very
close to the exit velocity obtained by using a wood bat and
substantially less than the exit velocity resulting from an
existing 2.750 inch diameter metal bat.
[0046] The metal baseball bat of the present invention should meet
the following specifications. First, the length of the bat in
inches shall not be more than 3 units greater than the weight of
the bat in ounces, without the grip wrap. Second, the bat barrel
diameter shall be no greater than 2.625 inches. A certified bat
ring (no more than a 1/4 inch thick) with an interior diameter of
2.635 inches must pass completely over the length of the bat.
Third, the center of gravity, or balance point, of the bat must be
at least 21.5 inches as measured from the end of the bat at the
knob end. The ball exit velocity under the 72.times.72 test must
not exceed 93.+-.1 mph.
[0047] The foregoing description should be considered as
illustrative only of the principles of the invention. Since
numerous modifications and changes will readily occur to those
skilled in the art, it is not desired to limit the invention to the
exact construction and operation shown and described, and,
accordingly, all suitable modifications and equivalents may be
resorted to, falling within the scope of the invention.
* * * * *