Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BAT HAVING A FLEXIBLE HANDLE
FIELD OF THE INVENTION
This invention relates to a ball bat, and more particularly to a ball bat with
a
striking barrel member made to provide desired striking capabilities, and a
handle
member made to provide desired swinging capabilities, and a method for
manufacturing
such which produces a rigid interconnection between the barrel and handle
members.
BACKGROUND AND SUMMARY OF THE INVENTION
Tubular metallic baseball bats are well known in the art. A familiar example
is a
tubular aluminum bat. Such bats have the advantage of a generally good impact
response, meaning that the bat effectively transfers power to a batted ball.
This effective
power transfer results in ball players achieving good distances with batted
balls. An
additional advantage is improved durability over crack-prone wooden bats.
Even though presently known bats perform well, there is a continuing quest for
bats with better hitting capabilities. Accordingly, one important need is to
optimize the
impact response of a bat. Further, it is important to provide a bat with
proper weighting
so that its swing weight is apportioned to provide an appropriate center of
gravity and
good swing speed of impact components during use.
Generally speaking, bat performance may be a function of the weight of the
bat,
distribution of the weight, the size of the hitting area, the effectiveness of
force transfer
between the handle and the striking barrel, and the impact response of the
bat. The
durability of a bat relates, at least in part, to its ability to resist
denting or cracking and
depends on the strength and stiffness of the striking portion of the bat. An
attempt to
increase the durability of the bat often produces an adverse effect on the
bat's
performance, as by possibly increasing its overall weight and stiffness, or
having less
than optimum weight distribution.
It has been discovered that a hitter often can increase bat speed by using a
lighter
bat, thereby increasing the force transferred to the ball upon impact. Thus it
would be
advantageous to provide a bat having a striking portion which has sufficient
durability to
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withstand repeated hitting, yet which has a reduced overall bat weight to
permit
increased bat speed through use of an overall lighter weight bat.
It also has been discovered that greater hitting, or slugging, capability may
be
obtained by providing a bat with a handle made of a material different from
the material
of the striking portion or formed in such a manner as to have different
capabilities. One
manner for providing such is to produce a bat with a composite handle, wherein
the
composite material may be structured to provide selected degrees of
flexibility, stiffness,
and strength. For example, in one hitting situation it may be best to have a
bat with a
more flexible handle, whereas for other hitting situations it is advantageous
to have a
handle with greater stiffness.
An example of a prior attempt to provide a bat with a handle connected to a
barrel section is shown in U.S. Patent 5,593,158 entitled "Shock Attenuating
Ball Bat."
In this patent an attempt was made to produce a bat with handle and barrel
member
separated by an elastomeric isolation union for reducing shock (energy)
transmission
from the barrel to the handle, and, inherently from the handle to the barrel.
Accordingly, such a design does not allow for maximum energy transfer from the
handle
to the barrel during hitting. As a result, the bat produces less energy
transfer or impact
energy to the ball due to the elastomeric interconnection between the handle
and barrel.
Therefore there is a continuing need for a bat that provides the flexibility
of a
separate handle member and striking member and maximizes the energy transfer
between the two members.
The present invention provides an improved bat with a striking portion with
good
durability and striking capabilities and a handle portion with desirable
weight and
stiffness characteristics to permit greater bat speed during hitting.
One embodiment of the invention provides a bat having an elongate tubular
striking member with a juncture section which converges inwardly toward the
longitudinal axis of the bat on progressing toward an end of the striking
member, and an
elongate handle member having an end portion thereof which is firmly joined to
the
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converging end portion of the striking member to provide a rigid
interconnection
therebetween to permit substantially complete striking energy transfer between
the
handle member and the striking member.
In another embodiment, the bat has an elongate tubular striking member having
a
juncture section adjacent its proximal end, the striking member being composed
of metal
having a first effective mass, and an elongate handle member composed of a
material
having a second effective mass which is less than the first effective mass of
the striking
member, the handle member having a juncture section adjacent its distal end,
with the
juncture sections of the striking member and handle member overlapping and
being
joined together to provide a rigid interconnection therebetween to permit
substantially
complete striking energy transfer between the striking member and the handle
member
on hitting. Because the handle member is of a lower effective mass it will
help to
produce a lighter weight bat with the possibility of a greater swing speed.
The present invention provides a novel bat and method for producing the same
wherein the striking portion is comprised of the most appropriate, or optimum,
structure
for striking and the handle is comprised of the most appropriate, or optimum,
structure
for swinging, and the two are joined for optimum slugging capability.
The present invention provides a bat, and method for making a bat, wherein
selected materials are used in selected portions of the bat to achieve proper
weight, or
mass, distribution for optimum swing speed and to provide desired strength and
stiffness
of selected portions.
According to a principal aspect of a preferred form of the invention, a bat
has a
longitudinal axis and an overall first length, and is capable of being tested
with a three-
point bend stiffness test device having first and second supports. The bat
includes an
elongate tubular striking member and a separate handle member. The striking
member has
a distal end, a proximal end, and a striking region intermediate the distal
and proximal
ends. The handle member has a distal end and a proximal end, and is coupled to
the
striking member. The handle member has a resistance to bending along the
longitudinal
axis of the bat in the range of 10-1000 lbs/in a three-point bend stiffness
test wherein the
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handle member is transversely supported in a first direction by the first and
second
supports spaced apart a selected distance, with the first support adjacent the
distal end and
the second support adjacent the proximal end, and the handle member is
transversely
loaded in a second direction, opposite the first direction, at a location on
the handle
member in a region between 30% and 40% of the selected distance from the
distal end of
the handle member.
According to another principal aspect of the present invention, a bat has a
longitudinal axis, and is capable of being tested with a three-point bend
stiffness test
device having first and second supports. The bat includes a non-wooden, one-
piece bat
frame. The frame includes a distal end, a proximal end, an elongate tubular
striking
portion, and a handle portion. Either the handle portion or the striking
portion includes a
tapered region. The frame has a resistance to bending along the longitudinal
axis in the
range of 10-950 lbs/in a three-point bend stiffness test wherein the frame is
transversely
supported in a first direction by the first and second supports, wherein the
first support is
positioned at a first predetermined position, wherein the first predetermined
position being
the location where the tapered region has a first predetermined outer
diameter, wherein the
second support positioned a first predetermined distance from the first
predetermined
position, and wherein the frame is transversely loaded in a second direction,
opposite the
first direction, on the handle member at a second predetermined position that
is located on
the handle portion a second predetermined distance from the first
predetermined position.
The second predetermined distance is between 30% and 40% of the first
predetermined
distance.
According to another principal aspect of the present invention, a method of
categorizing a plurality ball bats includes the following steps. At least two
distinct bat
categories are created based upon at least one bat characteristic. The at
least one bat
characteristic includes either the resistance to bending of the frame of the
bat or the
resistance to bending of the handle portion of the frame of the bat. The
method further
includes determining the resistance to bending of one of the frame and the
handle portion
for the plurality of bats. The method also includes assigning one of the at
least two
categories to each of the plurality of bats based, at least in part, upon
either the
resistance to bending of the frame or the resistance to bending of the handle
portion.
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The present invention contemplates producing a handle member with multiple
composite layers which are appropriately oriented and joined to provide a
handle which
has selected strength and stiffness. By providing a bat with a handle member
made of
composite material which may be laid up in multiple layers with selected
orientation and
strength, the handle member may be structured to provide selected degrees of
strength,
flexibility, and vibration transfer in an assembled bat. The present invention
also
contemplates producing a handle member of a thermoplastic material.
In one embodiment, one of the juncture sections of the striking member or the
juncture section of the handle member has projections thereon which extend
radially
from remainder portions of the juncture section a distance substantially equal
to the
thickness of a desired layer of adhesive to join the striking member and
handle member.
Such projections firmly engage the facing surface of the other member and
this, in
conjunction with the adhesive applied between the two members, provides a firm
interconnection therebetween.
This invention will become more fully understood from the following detailed
description, taken in conjunction with the accompanying drawings described
herein
below, and wherein like reference numerals refer to like parts.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a sectional view through the longitudinal center of a bat in
accordance with one embodiment of the invention.
FIGURE 2 is a magnified sectional view of a juncture section of the bat of
FIG. 1.
FIGURE 3 is a cross sectional view taken generally along the line 3-3 in FIG.
2.
FIGURE 4 is a view taken generally along the line 4-4 in FIG. 2, with a
portion
of the striking member broken away.
FIGURE 5 is a view similar to FIG. 4, but with a different rib configuration.
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FIGURE 6 is a magnified sectional view of a portion of the handle taken
generally along the line 6-6 in FIG. 2.
FIGURES 7-9 are perspective views of a flared end portion of the handle with
forming members associated therewith during the production of the handle
member to
produce projecting ribs on the juncture section of the handle.
FIGURE 10 is an enlarged longitudinal cross section of a handle member as may
be used in the bat of FIG. 1, with portions broken away to illustrate
composite lay up of
the handle member with multiple composite material layers disposed at various
regions
along the length of the handle and with some sections of the handle having
more layers
than others and being composed of different materials to obtain selected
handle member
mass, strength and stiffness characteristics.
FIGURE 11 is a side elevation view of a test fixture for testing the bending
strength of a handle member with an exemplary handle member mounted therein
for
testing.
FIGURE 12 is a side elevation view of a test fixture for testing the bending
strength of a full length assembled bat with an exemplary handle member
mounted
therein for testing.
FIGURE 13 is a side view of a bat having a one-piece integral frame.
FIGURE 14 is a side elevation view of a test fixture for testing the bending
strength of a bat with an exemplary assembled bat, or a bat having a one-piece
integral
frame, mounted therein for testing.
DETAILED DESCRIPTION
Referring to FIG. 1, an elongate tubular ball bat 10 having a longitudinal
axis, or
centerline, 20 comprises an elongate tubular striking member 12. The striking
member
has a proximal, or inner, end 12a and a distal, or outer, end 12b. A striking
region 14
is disposed intermediate ends 12a, 12b. A frusto-conical juncture section 16
of the
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striking member adjacent end 12a converges toward centerline 20 on progressing
toward
end 12a.
In the embodiment illustrated in Figs. 1 and 2 striking region 14 has a
substantially cylindrical inner cavity, with an inner diameter D,. A
cylindrical tubular
S insert 22 is received in the striking region cavity to form a multiple-wall
bat. The insert
has proximal, or inner, and distal, or outer, ends 22a, 22b, respectively. End
22a is
disposed adjacent juncture section 16. The bat also could be made as a single-
wall bat
without insert 22.
Juncture section 16 has a major diameter equal to D, and a minor diameter
noted
DZ at its end 12a.
An elongate tubular handle member 30 is secured to and projects longitudinally
outwardly from end 12a and juncture section 16 of the striking member.
The assembled bat 10 has an overall length L,. Striking member 12 has a length
LZ and handle member 30 has a length L3. As seen lengths LZ and L3 are each
substantially less than L,.
The handle member 30 in the illustrated embodiment may be made of a
composite material or other appropriate material as will be discussed in
greater detail
below. It has opposed distal, or outer, end 30a, and proximal, or inner, end
30b. The
handle member has an elongate, hollow, tubular, substantially cylindrical
gripping
portion 32 of a diameter D3 throughout a major portion of its length, and a
frusto-conical
juncture section 34 adjacent end 30a. As best seen in Figs. 1 and 2, juncture
section 34
diverges outwardly from the longitudinal axis in a configuration complementary
to the
converging portion of juncture section 16 of the striking member. Juncture
section 34
has a minor diameter D3 (less than DZ), a major diameter D4 (greater than D2,
but less
than D,), and a length which is no greater than 25 % of the overall length L,
of the
assembled bat.
End 12a of striking member 12 provides an opening with a diameter DZ greater
than diameter D3 of gripping portion 32 of handle member 30. The diverging
portion of
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juncture section 34 of the handle member is such that the outer surface of
juncture
section 34 is substantially complementary to the configuration of the inner
surface of
juncture section 16 of the striking member so that they may fit in close
contact with each
other when assembled as illustrated in Figs. 1 and 2.
Referring to Figs. 3 and 4, it will be seen that juncture section 34 of the
handle
member in the illustrated embodiment has a plurality of elongate, radially
extending ribs,
or projections, 40 on its outer surface. These ribs extend substantially
longitudinally of
the handle member, and are spaced apart circumferentially substantially
equally about
juncture section 34, or at approximately 120° fran each other as
illustrated.
Projections, or ribs, 40 extend outwardly from remainder portions of the
juncture
section of the handle member a distance substantially equal to the thickness
of a layer of
adhesive which it is desired to apply between juncture section 16 of the
striking member
and juncture section 34 of the handle member to secure these two members
together to
form the completed bat. It has been found desirable to apply a layer of
adhesive
between the juncture sections of the handle member and the striking member,
which is in
a range of 0.001 to 0.010 inch thick, and preferably within a range of 0.002
to 0.005
inch thick. Thus ribs 40 project outwardly from remainder portions of juncture
section
34 a distance in a range of 0.001 to 0.010 inch and more preferably in a range
of 0.002
to 0.005 inch.
When assembled as illustrated in the drawings, the outer surfaces of
projections
40 firmly engage the inner surface of juncture section 16 of the striking
member, with a
layer of adhesive filling the space between the circumferentially spaced ribs,
or
projections, to adhesively join the striking member to the handle member in
this juncture
section. A layer of such adhesive is indicated generally at 42.
Although projections 40 are shown as formed on the handle, it should be
recognized that projections formed on the inner surface of the juncture
section of the
striking member and extending radially inwardly from remainder portions of the
striking
member could be used also.
_g_
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FIG. 4 illustrates an embodiment of the invention in which the ribs 40 are
substantially straight, and extend longitudinally of the handle member. FIG. 5
illustrates
another embodiment in which the ribs 46 are curved, such that they extend
somewhat
helically about the outer surface of juncture section 34. They function
similarly to ribs
40.
Although the projections, which may be formed on the external surface of the
juncture section of the handle or on the internal surface of the juncture
section of the
striking member, have been illustrated and described generally as elongate
ribs, it should
be recognized that the purpose of such projections is to provide a firm
contacting
engagement between the juncture section portions of the handle member and
striking
member to produce a substantially rigid interconnection therebetween. Thus,
the
projections do not necessarily have to be elongate ribs as illustrated.
Instead, there
could be a plurality of projections of substantially any shape extending
outwardly from
remainder portions of the juncture section of the handle member or projecting
inwardly
from the inner surface of the juncture section of the striking member, or any
combination thereof, such that firm interengagement is provided between the
striking
member and the handle member. For example the projections may be a pebbled
surface
configuration, criss-crossed ribs, irregularly shaped ribs, or any other
configuration that
provides a plurality of raised surfaces for direct contact with the other
member to
provide a substantially rigid interconnection between the handle member and
the striking
member.
The complementary converging and diverging configurations of the juncture
sections of the striking member and handle member prevent the two parts from
being
pulled apart longitudinally in opposite directions, such as by pulling
outwardly on
opposite ends of the bat. The adhesive is provided to inhibit longitudinal
movement of
the handle member and striking member upon application of forces thereagainst
such as
might occur if forces were exerted at opposite ends of the bat in an attempt
to compress
them toward each other.
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Although adhesive has been noted as a means for securing the two members
against relative longitudinal movement in the one direction, it should be
recognized that
other means could be used also. For example, mechanical locking means of
various
types could be employed. Although not shown herein, the striking member or
handle
member could be formed with a radially projecting lip which engages a portion
on the
other member when the parts are moved into the positions illustrated in Figs.
1-4 to
prevent longitudinal separation of the members.
Further, although it has been mentioned that adhesive can fill the spaces
between
the projections, it is not necessary that the spaces between the projections
always be
filled, and a less than filling quantity of adhesive may be adequate.
When assembled as illustrated in the drawings, juncture section 34 of the
handle
member fits tightly within juncture section 16 of the striking member and a
layer of
adhesive interposed therebetween rigidly interconnects the striking member and
handle
member.
In a particularly preferred embodiment, the striking member 12 is a one-piece
integrally formed generally tubular member, and the handle member 30 is a one-
piece
integrally formed tubular unit. The striking and handle members 12 and 30 are
preferably connected to each other such that at least a portion of the
striking member 12
directly contacts at least a portion of the handle member 30. A non-metallic
substance
(an adhesive) is also preferably disposed between the handle and striking
members 12
and 30 to further secure the connection between the handle and striking
members.
In other alternative preferred embodiments, the handle and striking members
can
be coupled together in a manner that prevents direct contact between the
handle and
striking members. In such alternative preferred embodiments, a non-metallic
substance
can be used to couple the handle member to the striking member. The non-
metallic
substance can be an adhesive, an elastomer, an epoxy, a chemical bonding agent
or
combinations thereof. In other alternative preferred embodiments, other types
of
conventional fastening or coupling means, including metallic fasteners and
rings, can be
used. Further, because direct contact between the handle and striking members
is not
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necessarily present in these alternative preferred embodiments, the juncture
sections each
of the handle and striking members can be formed with or without ribs or other
projections.
The fully assembled bat as shown in FIG. 1 includes a knob 48 secured to the
proximal end 30b of the handle member and a plug 50 inserted in and closing
the distal
end 12b of the striking member. Referring to FIG. 1, a weighted member, or
plug, 54
is inserted and secured in the proximal end portion of handle member 30. The
structure
and function of member 54 will be described in greater detail below.
A generally cylindrical transition sleeve 52 having a somewhat wedge-shaped
cross section as illustrated in FIG. 2 is secured to handle member 30 to abut
end 12a of
the striking member to produce a smooth transition between end 12a of the
striking
member and the outer surface of handle member 30. Rather than applying a
transition
sleeve 52, the proximal end 12a of juncture section 16 of the striking member
may be
swaged to a gradually thinner edge region with a rounded proximal edge.
Describing a method by which the bat illustrated in the figures may be
produced,
striking member 14 is formed of a material and in a manner to provide desired
impact,
or striking capabilities. The striking member may be formed by swaging from
aluminum tube (or other metal found appropriate for the striking region of a
bat) to yield
an integral weld-free member. While swaging is one means of producing such
striking
member, it should be understood that other methods of manufacturing might work
equally as well.
The striking member is formed with a circular cross section having a striking
region which has a cylindrical interior surface defining an interior cavity of
a first
selected cross sectional dimension, or diameter, D, . This produces a striking
member
having a first effective mass. The effective mass may be a function of the
specific
gravity of the material, size, thickness, or other characteristics.
The juncture section 16 converges inwardly toward longitudinal axis 20 to an
opening at end 12a having an internal diameter indicated DZ which is less than
D,.
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Insert 22 has an outer diameter corresponding generally to, but possibly
slightly
smaller than, D, such that it may be inserted into the striking portion 14 of
striking
member 12. Its proximal, or inner, end 22a may engage the beginning of the
inward
converging portion of juncture section 16 which prevents the insert from
shifting further
toward end 12a of the striking member. End 12b of the striking member 12 is
bent over
to form a circular lip with a bore extending therethrough. An end plug 50 is
placed in
the end of the bat to engage end 22b of the insert to hold it in place.
The striking member 12 may be formed of tubular metal material of a first
specific gravity, which may be, but is not limited to, aluminum, steel,
titanium, or other
suitable metal material. The striking member also might be formed of composite
or
other suitable materials. Insert 22 also may be made of any such tubular metal
or a
composite. The insert serves a function as set out in prior U.S. Patents
5,415,398 and
6,251,034. Since the striking member is formed separately from the handle
member,
the striking member may be formed in such a manner and from such materials as
to
produce the desired, or optimum, impact, or striking capabilities. Thus the
requirements
of the striking member and handle member are decoupled permitting each to be
made of
such materials and in such a manner as to provide optimum point location of
mass in the
bat and optimum strength and stiffness or flexibility where needed.
The handle member may be formed from material, which produces a different,
and generally a lower, effective mass than it would have if composed in a
manner or of a
material similar to that from which the striking member is formed. The
different
effective mass of the handle member may be a function of the specific gravity
of the
material forming the striking member, its size, thickness or other
characteristics. For
example the material of the handle member may have a different specific
gravity than the
material from which the striking member is formed. In one preferred
embodiment, the
handle member is formed of a thermoplastic material, a fiber reinforced
thermoplastic
and combinations thereof. Some examples of thermoplastic materials include
nylon,
urethane, ABS, polyvinylchloride and combinations thereof. The fiber
reinforced
thermoplastic material can include fibers formed of fiberglass, aramid,
carbon,
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Kevlar~, high molecular weight polyethylene in strand form, or other
conventional fiber
materials.
In some instances the handle member may be formed of a composite material,
such as carbon fiber, having a second specific gravity less than the first
specific gravity
of the striking member. In other instances the handle member may be formed of
materials or in such a manner as to provide one or more operational or
functional
characteristics which differ from those which the handle member would have if
merely
formed in the same manner of the same material as the striking member. For
example
the handle may be formed from other materials such as titanium, aluminum,
plastic or
other appropriate material.
Referring to FIG. 6, in one embodiment the handle member includes multiple
tubular composite layers as indicated generally at 60-66. The layers 60-66 are
disposed
adjacent each other and are arranged in a substantially concentric manner. The
number
of layers must be sufficient to withstand the swinging action of the bat, a
gripping force
applied thereto by a user, and the bending force imposed thereon when striking
with the
bat. However, preferably only the number of layers necessary to withstand such
stresses
would be provided, since more layers will add additional weight to the handle
member.
The number, position, and orientation of the multiple layers will vary
depending upon
the size and type of bat used. In one embodiment, the handle member may
include the
seven layers, 60-66, as shown. The number and thickness of layers and their
position,
and orientation may vary as needed to provide desired flexibility or stiffness
and to
withstand gripping forces and hitting stresses.
Each composite layer in the embodiment illustrated includes structural
material to
provide structural stability and matrix material to support the structural
material. The
structural material may be a series of fibers supported within the matrix
material. In one
preferred embodiment, most of the layers include fibers that preferably extend
substantially longitudinally of the handle member. When the bat strikes a
ball, the
greatest stress component on the handle member may be in bending, thus the
majority of
the fibers preferably are directed longitudinally to withstand these stresses.
For
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example, the even numbered layers 60, 62, 64, 66 may be longitudinally
extending
layers, whereas odd numbered layers 61, 63, 65, which are fewer in number, may
be
circumferentially disposed layers. The longitudinally extending layers often
are referred
to as longitudinal, or 0° layers, since they have fibers that are
directed substantially
parallel to the longitudinal axis. The other layers may be what are termed
90° layers, or
circumferential layers, since they have fibers, in which the majority thereof
are directed
at substantially 90° relative to the longitudinal axis. Specific layers
may be constructed
with fibers directed at substantially 90° relative to the longitudinal
axis and other fibers
directed at substantially 0° and v~oven together within each layer. Or
the layers may be
uni-directional layers wherein the fibers within the layers are parallel.
In another preferred embodiment, one or more of the multiple tubular composite
layers 60-66 can formed primarily of fibers extending in a non-longitudinal
direction,
with only a small percentage, or none, of the fibers extending in a
longitudinal direction.
In this preferred embodiment, the fibers can be laid substantially 90°
from the
longitudinal axis, in various angled positions between 1-89°, or in
combinations thereof.
By having a small percentage, or none, of the fibers extending at 0°
(lrngitudinally), the
stiffness of the handle can be reduced and optimized to fit a particular
application. In
another alternative preferred embodiment, one or more of the multiple
composite layers
can be formed of fibers, or fiber segments, in a random, or generally
uniformly,
configuration.
In this embodiment, the layers include carbon fibers. However the fibers could
be other type of known fiber material, such as, but not limited to, KevlarTM,
boron,
aramid, fiberglass, or high molecular weight polyethylene in strand form. A
metallic
mesh also might be used.
The matrix in the layers preferably is sufficiently durable and has
sufficiently
high adhesion properties to continue supporting the structural material even
after
repeated use. In a preferred embodiment, the matrix material is a toughened
epoxy.
Alternatively, the matrix can be some other thermally setting resin such as a
polyester or
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vinyl ester. A person skilled in the art will appreciate that a thermoplastic
resin can be
used, rather than a thermally setting resin.
In particularly preferred embodiments, the handle member 30 has a weight of
about 158 grams and is formed with the number of layers between 28 to 40,
wherein the
weight of each layer varies from 0.6 to 14.0 grams. At least one layer of such
embodiments is a braided layer having a percentage of the fibers within the
braided layer
extending longitudinally and the remaining fibers of the braided layer
extending
substantially circumferentially. Also, from 1 to 4 layers are formed with non-
woven or
non-braided fibers extending in two separate directions, such as, for example,
0 degrees
and 90 degrees.
Additionally, in particularly preferred embodiments, the handle member 30
includes between 2 and 10 layers having longitudinally extending fibers. In
particularly
preferred embodiments, the handle member 30 includes a plurality of layers
having
helically extending fibers at various angles relative to the longitudinal
axis, such as, for
example, between 10 and 16 layers extend at plus or minus 30 degrees from the
longitudinal axis, between 6 and 16 layers extend at plus or minus 45 degrees
from the
longitudinal axis, and 2 or less layers extend at plus or minus 60 degrees
from the
longitudinal axis.
Also, in particularly preferred embodiments, between 3 and 24 layers are
formed
of carbon fibers and between 13 and 25 layers are formed of fiberglass fibers.
The
layers are formed in a variety of different lengths varying from 5 cm to 67
cm. The
layers, which are less than 67 cm, are placed at varying positions along the
full length of
the handle member. The layers are also formed in a variety of different widths
ranging
between 3.3 and 17.5 cm. Other layers have widths that vary along their length
from
between 0 to 17.5 cm. The number of layers having widths that vary along their
length
range between 8 and 11 layers. The fibers within layers are formed with an
area fiber
density of between 0.0143 and 0.048 grams/cm2, and each layer can be formed
with a
weight in a range of 0.6 to 14 grams.
-15-
CA 02488084 2004-11-19
In alternative preferred embodiments, one or more of the characteristics of
the
handle member can be altered, such as, for example: the weight, size,
thickness and
stiffness of the handle member; the number, size, composition and orientation
of the
layers; and the composition, density, and orientation of the fibers within a
layer. The
handle member preferably has a weight within a range of 3 to 8 ounces. The
handle
member 30 can be formed without a braided layer or with an alternate number of
braided layers. The handle member 30 can be formed with five or more layers of
fibers
wherein the non-woven fibers extend in two directions or with no such layers.
Two or
more of the layers can include other combinations of longitudinally,
circumferentially
and helically extending fibers. The handle member can be formed of multiple
layers
having helically extending fibers wherein any one layer can have fibers
extending
between plus or minus 1 to 89 degrees from the longitudinal axis. The fibers
within the
layers can be formed of other materials, such as, for example, glass, boron,
graphite or
other metal.
FIG. 10 is a simplified illustration of the manner in which multiple layers of
fiber
composite material may be assembled. As is shown some of the layers extend the
full
length of the handle (layers 90a, b, c, d), while others are shorter and
reside in selected
regions of the handle member (90e, f, g, h, i, j, k). Only a limited number of
layers are
shown in FIG. 10, for the sake of simplicity in the illustration.
The handle member includes a proximal gripping portion and a distal tapered
portion, wherein one of the proximal gripping portion and the distal tapered
portion is
formed with a larger number of layers than the remaining portion. The
characteristics of
the handle member therefore can vary over its length.
The handle member 30, when formed of a composite material and produced in
accordance with the present invention, can be produced with a stiffness, or
resistance to
bending along the longitudinal axis 20 of the bat 10, within the range of 10
to 1980
lbs/in. when measured using a test method described below. In one preferred
embodiment, the handle member 30 is formed with a stiffness or resistance to
bending
within the range of 400-900 lbs/in. (The term "lbs/in." refers to the amount
of force in
-16-
CA 02488084 2004-11-19
pounds applied perpendicular to the member to produce on inch of deflection in
a test
method described below.)
In other alternative preferred embodiments, the handle member 30 is formed
with
a stiffness, or resistance to bending along the longitudinal axis 20 of the
bat 10, at
specific levels within the range of 10 to 1980 lbs/in. The inventors of the
present
invention have discovered that, contrary to conventional bat design and
construction,
when the handle member 30 of the bat 10 is configured with a low stiffness, or
resistance to bending along a longitudinal axis of the bat, the feel and
perceived
performance of the bat 10 significantly improves without negatively affecting
the
reliability of the bat. The present invention contemplates multiple preferred
embodiments of ball bats in which the stiffness, or a resistance to bending
along the
longitudinal axis of the bat, of the handle member 30 is significantly lower
than
conventional bats. While conventional bat design focuses on bats having a
resistance to
bending typically far above 1000 lbs/in. (often 2200-2500 lbs/in for
conventional
metallic bats), in order to prevent the bat from becoming "too whippy," the
present
invention incorporates ball bats having handle members with significantly
lower stiffness
values (resistance to bending along the longitudinal axis of the bat), which
are then tuned
or optimized to maximize the feel and performance of the ball bat for a
particular user.
Conventional performance bat design seeks to obtain a stiff handle member or
portion to be used in conjunction with a responsive striking member or
portion. A
responsive striking member or portion provides the desired trampoline effect
upon
impact with a ball, and a stiff handle member maximizes the mass and the force
that can
be applied or transferred to the ball upon impact with the striking member or
portion. A
stiffer handle member or portion is also desired under conventional bat design
because it
allows the batter to bring the head of the bat around for impact faster and in
a more
controlled manner.
Contrary to conventional performance bat design, the inventors of the present
invention have discovered that producing a handle member, or portion, of a bat
with a
significantly lower resistance to bending in a longitudinal direction along
the bat,
-17-
CA 02488084 2004-11-19
provides the bat with a significantly improved feel to the user, particularly
during off
center hits. Existing metallic and composite ball bats often provide painful
stinging or
harsh vibrational feedback through the handle member or handle portion of the
bat to the
user when the bat contacts the ball away from the "sweet spot" of the striking
member.
This effect is often heightened at lower temperatures. A bat having a handle
member, or
portion, with a very low resistance to bending in the longitudinal direction
of the bat,
however, significantly improves the feel of the bat by altering or reducing
the size or
configuration of the impact energy extending along the bat. The handle member
or
handle portion having the low resistance to bending tends to isolate, alter
and/or reduce
the painful, harsh vibrational energy generated in a bat from an off center
impact with a
game ball.
Often, the harsh or painful sensation felt by a batter when impacting a ball
can
have a significant negative impact on the ball player, particularly younger or
less skilled
players who do not always contact the ball at the sweet spot of the striking
member or
portion. Many players consciously, or subconsciously, alter or reduce the
speed, motion
or fluidity of their swing in an effort to avoid experiencing the stinging or
harsh
vibrational energy that can be generated upon impact with a ball. The handle
member or
handle portion, having a significantly reduced resistance to bending, alters,
dampens,
separates, isolates and/or reduces this negative vibrational energy or
sensation
transmitted to the ball player, particularly during mis-hits. After repeated
use of such
bats having a handle member or portion with a significantly lower resistance
to bending,
the ball player experiences the improved feel provided by the bat,
particularly during
mis-hits. The player typically will become more aggressive at the plate,
swinging freer,
smoother and often faster, thereby often improving his or her performance,
even when
mis-hitting the ball. Further, more skilled batters may be able to adjust
their swings to
maximize the impact of the significantly more flexible handle members. More
skilled
players potentially can bring the barrel or striking portion of the bat around
into the
point of impact with a ball in a manner that takes advantage of the
flexibility of the
handle to produce potentially greater bat head or striking portion speed.
-18-
CA 02488084 2004-11-19
By lowering the resistance to bending of the handle member 30 well beyond the
level of conventional bats, the present invention creates a significantly
broader range of
bat configurations and provides the ability to properly match a bat to a ball
player.
Other factors such as the player's size, age, strength, skill level and swing
speed, as well
as the type of ball game being played can be used along with the resistance to
bending of
the handle member to select a ball bat that is best suited for an individual
player. The
present invention includes a large number of bat configurations having
resistance to
bending levels that are significantly lower than conventional bats. In one
particularly
preferred embodiment, the handle member has a resistance to bending along the
longitudinal axis within the range of 900-1000 lbs/in. In another particularly
preferred
embodiment, the handle member has a resistance to bending along the
longitudinal axis
within the range of 800-900 lbs/in. In another particularly preferred
embodiment, the
handle member has a resistance to bending along the longitudinal axis within
the range
of 700-800 lbs/in. In other particularly preferred embodiments, the handle
member can
have a resistance to bending along the longitudinal axis within the ranges of
600-700
lbs/in., 500-600 lbs/in., 400-500 lbs/in., 300-400 Ibs/in., 200-300 lbs/in.,
100-200
lbs/in., 10-100 lbs/in., or combinations and variations of these ranges. Each
one of
these ranges, or variations of these ranges, can be used to provide a bat
having a
resistance to bending that is best suited for a particular ball player for a
particular type
of ball game. Each of these ranges or range variations can be used to produce
an
optimal bat for a particular type of ball player for a particular application.
Referring to FIG. 11, the stiffness of the handle member 30 is determined
through a three-point bend stiffness test wherein the handle member is placed
upon first
and second supports 90 and 92 of a universal test machine, or similar test
machine, such
as the universal test machine produced by Tinius Olsen Testing Machine Co.,
Inc. of
Willow Grove, Pennsylvania. The first support 90 is a V-block support
positioned at the
distal end 30a of the handle member 30. The V-block support configuration of
the first
support 90 also serves to inhibit both longitudinal and transverse movement of
the distal
end 30a of the handle member 30. The second support 92 is a roller support
including a
roller 94 rotatable about a horizontal axis 96 spaced from V-block support 90
and
positioned near the proximal end 30b of the handle member 30. For handle
members 30
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CA 02488084 2004-11-19
greater than or equal to 19 inches, the second support 92 is positioned a
distance D6 of
19 inches from support 90. The second support 92 also supports the handle
member 30
in a first direction, preferably by maintaining the proximal end such that the
longitudinal
axis 20 of the bat 10 is in a substantially horizontal position. The second
support 92
S enables the proximal end 30b to move longitudinally.
The third point of the bend stiffness test is provided by a crosshead 100,
preferably having a semi-circular or circular shape. Most preferably, the semi-
circular
crosshead has a radius of 2.0 inches. The crosshead is configured to extend in
a second
direction opposite of the first direction. The crosshead may be moved
downwardly onto
L 0 the horizontally positioned handle member 30 with a force noted F, imposed
thereon.
The crosshead is connected to a load cell (not shown) which includes a strain
gauge for
measuring the load applied to the crosshead during displacement of the
crosshead. The
crosshead 100 is positioned a distance D, from the first support 90. Distance
D, is in a
range of 30 % to 40 % of distance D6, and more preferably 7 inches, such that
the
15 semicircular crosshead contacts the handle member at a location
approximately 7.0
inches from the distal end 30a of the handle member 30.
During testing, the handle member is positioned as described above. The
crosshead is driven in the second direction at a speed of 1.0 inches per
minute. As the
crosshead moves in the second direction (i.e., downwardly in FIG. 12) the
testing
20 machine with input from the load cell calculates the load (F~) per the
lateral deflection,
or displacement, of the handle member 30.
Table 1 below illustrates the resistance to bending along the longitudinal
axis of a
bat of handle members of an existing bat formed with separate striking and
handle
members, as well as handle members of bats formed under the present invention.
-20-
CA 02488084 2004-11-19
TABLE 1
RESISTANCE TO BENDING ALONG A LONGITUDINAL AXIS
FOR HANDLE MEMBERS OF BATS
HAVING SEPARATE HANDLE AND STRIKING MEMBERS
Test Sample Description Resistance
Sample to Bending
# (Ibslin)
Test Test Average
a b
Ts04-050 Easton~ Connexion T"" / z-core 1559.20 1553.481556.34
titanium / -3 besr
certified / 34" l 31 oz / mdl.
bt7-z / baseball / handle-
barrel se arated
ts04-060-1DeMarini~ Sample No. 1 18.79 18.21 18.50
Ts04-060 DeMarini~ Sample No. 2 25.94 24.97 25.45
Ts04-049 DeMarini~ Sample No. 3 30.71 31.51 31.11
ts04-049-1DeMarini~ Sample No. 4 36.71 38.82 37.77
Vxw DeMarini~ Sample No. 5 557.81 593.91 575.86
evo 1 DeMarini~ Sample No. 6 609.03 627.56 618.30
sf2 1 DeMarini~ Sample No. 7 797.58 720.04 758.81
handle-1 DeMarini~ Sample No. 8 1589.56 1530.031559.80
I
Eastori is a registered trade mark of Jas. D. Easton, Inc. ConnexionTM is a
trademark of Easton Sports, Inc.
The DeMarini~ Sample s 1-7 are examples of handle members of the present
invention having resistance to bending values well below the handle members of
existing
bats, which are configured with separate striking and handle members. The
handle
members having the reduced resistance to bending values provide the ball
player with a
significantly improved feel and perceived performance. DeMarini~ Sample 1 has
a
resistance to bending value that is over 95 % lower than the resistance to
bending of the
handle member of the existing Easton~ Co nnexion~' bat model of Table 1.
The bat 10 of the present invention can be formed with separate striking and
handle members 12 and 30 (see FIGS. 1-5) or as a bat 110 having an integral
one-piece
frame 110 as shown in FIG. 13. The frame 110 includes a striking portion 112
integrally connected with the handle portion 114. The frame 110 is formed of a
strong,
flexible material, preferably a composite material. Alternatively, other
materials can be
used, such as, for example, a tubular metal material or a combination of
composite and
metal materials. Through the use of composite materials throughout the frame
110, the
frame 110 can be designed with different characteristics in the striking
portion 112
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CA 02488084 2004-11-19
compared to the handle portion 114. Preferably, the handle portion 114 is
configured to
be significantly more flexible than the striking portion 112.
Referring to FIG. 12, one method of performing the three-point bend stiffness
test on an assembled bat is illustrated. When testing a bat the first support
92 is
positioned such that a proximal side of the first support lies a distance D8,
which may be
approximately 6 inches, from the distal end 12b of the striking member 12, and
the
second support 92 is positioned a distance D9, which may be approximately 6
inches,
from the proximal end 30b of the handle member 30. The distance between
supports 90,
92 is noted at D,o and the cross head is positioned a distance D,o from
support 92, which
is approximately one half D,o so as to contact the bat at a point between and
generally
equi-distant from the first and second supports.
During testing, the bat 10 is positioned as described above. The crosshead is
driven in the second direction (downwardly in FIG. 12) at a speed of 0.5
inches per
minute. As the crosshead moves in the second direction, the testing machine
with input
from the load cell calculates the load per displacement of the bat.
Referring to FIG. 14, another method of performing the three-point bend
stiffness test on an assembled bat is illustrated. The stiffness of the bat 10
(or 100) is
determined through a three-point bend stiffness test wherein the handle member
30 (or
handle portion 110) of the bat 10 (or bat 110) is placed upon the first and
second
supports 90 and 92 of the universal test machine, or similar test machine. The
first
support 90 is a V-block support positioned toward the distal end of the handle
portion 30
of the bat 10 and at the tapered region of the bat 10 (the tapered region can
be part of the
handle portion, part of the striking portion or a combination of both
portions). The
tapered region of the bat 10 is measured to identify the location of a
predetermined
outside diameter of the bat 10. Preferably, an outside diameter of 2.1 inches
is selected.
Alternatively, an outside diameter within the range of 2.1 to 2.25 inches can
be selected.
The tapered region of the bat 10 is placed into the first support 90 at the
location where
the predetermined outside diameter (preferably 2.1 inches) occurs. The V-block
support
-22-
CA 02488084 2004-11-19
configuration of the first support 90 also serves to inhibit the transverse
movement of the
bat 10.
The second support 92 is spaced from the V-block support 90 and is positioned
near the proximal end 30b of the handle member 30. The handle member or
portion is
then placed over the second support 92. The second support 92 is preferably
positioned
a distance D6 of 19 inches from support 90. The second support 92 also
supports the
handle member 30 in a first direction, preferably by maintaining the proximal
end such
that the longitudinal axis 20 of the bat 10 is in a substantially horizontal
position. The
second support 92 enables the proximal end 30b to move longitudinally. If the
bat 10
(or the bat 110) is configured such that the handle member 30 (or the handle
portion
110) of the bat 10 (or the bat 110) does not extend to the second support 92,
a different
predetermined outside diameter value along the tapered region of the bat 10
can be
selected. A diameter greater than 2.1 inches up to 2.25 inches can be used.
The third point of the bend stiffness test is provided by the crosshead 100.
The
crosshead is configured to extend in the second direction opposite of the
first direction.
The crosshead may be moved downwardly onto the horizontally positioned handle
portion or handle member 30 with a force noted F, imposed thereon. The
crosshead is
connected to the load cell (not shown) which includes the strain gauge for
measuring the
load applied to the crosshead during displacement of the crosshead. The
crosshead 100
is positioned a distance D, from the first support 90. Distance D, is in a
range of 30% to
40 % of distance D6, and more preferably 7 inches, such that the semicircular
crosshead
contacts the handle member at a location approximately 7.0 inches from the
location of
the predetermined diameter (preferably 2.1 inches along the tapered region of
the bat
10).
During testing, the handle member is positioned as described above. The
crosshead is driven in the second direction at a speed of 1.0 inches per
minute. As the
crosshead moves in the second direction (i.e., downwardly in FIG. 13) the
testing
machine with input from the load cell calculates the load (F~) per the lateral
deflection,
or displacement, of the handle member 30.
-23-
CA 02488084 2004-11-19
The bat of the present invention can be formed such that the stiffness of the
bat
is within the range of 10 to 2500 lbs/in. In one particularly preferred
embodiment,
the bat 10 is formed with a stiffness, or resistance to bending, within the
range of 500 to
1500 lbs/in, and more preferably in a range of 400-900 lbs/in. A conventional
5 aluminum bat typically has a stiffness, or resistance to bending, of
approximately 2200
to 2500 lbs/in. In one particularly preferred embodiment, the bat is formed
with a
resistance to bending along the longitudinal axis within the range of 800-950
lbs/in. In
another particularly preferred embodiment, the bat has a resistance to bending
along the
longitudinal axis within the range of 700-800 lbs/in. In other particularly
preferred
10 embodiments, the bat can have a resistance to bending along the
longitudinal axis within
the ranges of 600-700 lbs/in., 500-600 lbs/in., 400-500 lbs/in., 300-400
lbs/in., 200-300
lbs/in., 100-200 lbs/in., 10-100 lbs/in., or combinations and variations
thereof. Each
one of these ranges, or variations of these ranges, can be used to provide a
bat having a
resistance to bending that is best suited for a particular ball player for a
particular type
of ball game.
Table 2 provides a listing of the resistance to bending along the longitudinal
axis
of a number of existing ball bats and a number of ball bats configured under
the
present invention, measured using the second full (assembled) bat test method
described
above. (The term "lbs/in." refers to the amount of force in pounds applied
20 perpendicular to the bat to produce on inch of deflection in a test method
described
below.)
-24-
CA 02488084 2004-11-19
TABLE 2
RESISTANCE TO BENDING ALONG A LONGITUDINAL AXIS
OF ASSEMBLED BATS
Test Sample Description Resistance
Sample to Bending
# (Ibslin)
Test Test Average
a b
ts04-032 Easton~ ConnexionT"" I -3 / 33" 1413.79 1450.001431.90
/ 30 oz I baseball
ts04-033 Worth~ supercell est I cryogenic1683.40 1689.931686.67
I 34" ! 27 oz / softball
ts04-034 Easton~ z-core / -3 / titanium 2320.11 2173.162246.64
/ graphite reinforced
sc777 / 34" / 31 oz / mdl.bz71-2
/ baseball
ts04-035 Worth~ 3dx I -3 / 34" I 31 oz 2166.02 2087.442126.73
I model 3dxab I baseball
ts04-036 Easton~ Connexion T"" / -3 / 1518.40 1565.501541.95
32" l 29 oz / baseball
ts04-037 BaumO aaa-pro I 33" I 33 oz / 1895.87 1991.071943.47
baseball
ts04-038 Louisville Sluggert9 TPXT"" I 2313.61 2299.332306.47
gent x / -3 I 33" I 30 oz I
model cb203 / baseball _
ts04-039 Easton~ z2k / -3 / graphite reinforced2707.45 2656.002681.72
sc500 scandium
I mdl.bz2-kc / baseball
ts04-040 Easton~ (all aluminum) / youth 1328.10 1323.591325.84
baseball bat l 31"
ts04-041 Easton~ Connexion T"' z-core 1111.51 1151.691131.60
I 34" / 26 oz I mdl. st1-2 /
softball
ts04-042 Worthy WickedT"" / 34" l28 ox 1330.71 1375.981353.34
/ model wwsc / softball
ts04-043 Easton~ synergy / 34" 28 oz / 1005.63 992.40 999.02
mdl. Scx2 / softball
ts04-044 Louisville Sluggert~ TPS / air 1990.48 1891.511940.99
attack 3 / 34" / 28 oz /
model sb22 / softball
ts04-045 Louisville Sluggers TPS 1 air 1868.15 1835.371851.76
c555 / -10.5 oz / 34" I
model f 25 l fast itch
ts04-046 Mizuno~ techfire I victory stage2727.27 2780.902754.09
I 33" I model 2tp-50340
/ softball
ts04-047 Easton~ cxn Connexion T"" / sc8881094.30 1183.221138.76
/ 29" / 18.5 oz / mdl.
It8-z / outh baseball
ts04-048 Easton~ Connexion T"" / youth 1128.07 1120.311124.19
baseball bat / 31"
ts04-004 DeMarini~ Sample No. 9 306.44 306.40 306.42
ts03-191 DeMarini~ Sample No. 10 529.59 464.58 497.08
ts03-040 DeMarini~ Sample No. 11 668.60 674.12 871.36
wcb-32-1 DeMarini~ Sample No. 12 894.84 928.07 911.46
wcb-33-1 DeMarini~ Sample No. 13 906.95 944.00 925.48
ts03-151 DeMariniO Sample No. 14 1176.81 1164.741170.78
ts03-107 DeMarini~ Sample No. 15 2347.97 2348.822348.40
Easton~ is a registered trademark of Jas. D. Easton, Inc. Connexion T"' is a
trademark of Easton Sports, Inc.
S Worth~ is a registered trademark of Worth, inc. Wicked T"" is a trademark of
Worth, Inc. Baum~ is a
registered trademark of Baum Research & Development Company, Inc. Louisville
Slugger0 is a registered
trademark of Hillerich & Bradsby, Co. TPST"~ and TPXT"" are trademarks of
Hillerich & Bradsby, Co.
Mizuno~ is a registered trademark of Mizuno Corp.
Table 2 illustrates bats having different stiffnesses, or different resistance
to
bending values, of a number of existing ball bats. Table 2 also illustrates
the reduced
resistance to bending of the bats of DeMarini~ Samples 9-13. The DeMarini~
Samples
-2S-
CA 02488084 2004-11-19
are configured in accordance with the present invention and provide for
resistance to
bending values that are significantly lower than those measured on existing
ball bats.
The DeMarini~ Sample s 1-7 and 9-13 of Tables 1 and 2 illustrate only a few of
the
variations in handle stiffness or resistance to bending contemplated under the
present
invention.
As stated above, the present invention enables the bat to be produced with
significantly less stiffness, greater flexibility, and significantly better
feel to the player,
without negatively affecting the batting performance of the bat. The present
invention
enables one of ordinary skill in the art to vary the composition of the bat to
produce a
bat that is optimally configured, adjusted or tuned to meet the needs of a
particular
player. The present invention also enables one of ordinary skill in the art to
produce a
bat that optimizes flexibility and, through the direct connection between the
handle
member and the striking member, maximizes energy transfer between the handle
and
striking members, and the power output of the bat.
It should be noted that examples set out herein are only exemplary in nature,
and
should not be considered limiting as to the structure and method of
manufacture of bats
according to the invention. For example, although the bat has been described
with a
metal striking member and a composite handle member, such a wide difference in
materials for the two members may not be necessary. For example, the striking
member
and the handle member both may be made of composite material, but with
constructions
which provide varying operational or functional characteristics beneficial for
the specific
portion of the bat which they form.
The present invention also includes a method of categorizing a plurality ball
bats
or bat models (two or more) based, at least in part, upon the stiffness, or
the resistance
to bending of the bat along its longitudinal axis. The method includes
creating at least
two distinct bat categories, or groupings of bats, based upon at least one bat
characteristic. The at least two bat categories or groupings of bats can be
two, three,
four or more categories or groups. The at least one bat characteristic
includes at least
the resistance to bending of the frame of the bat along the longitudinal axis
of the bat, or
-26-
CA 02488084 2004-11-19
the resistance to bending of the handle portion of the frame of the bat along
the
longitudinal axis of the bat. Preferably, the at least one bat characteristic
used to create
the two or more categories or groupings of bats is two or more bat
characteristics,
wherein the second characteristic is the weight of the bat, the length of the
bat, the
application the bat was configured for, the material of the handle portion of
the bat, and
the material of the frame of the bat. Further characteristics of the ball
player for which
a particular bat is intended for also can be used. Such characteristics can
include a
batter's skill level, a batter's swing speed, a batter's experience level, a
batter's strength,
a batter's age, and a batter's size. Still further, the application for which
the bat is
intended for can also be used as one of the additional characteristics used to
define the
categories.
The method also includes determining the resistance to bending of either the
frame or the handle portion for the plurality of bats, or bat models. This
resistance to
bending along the longitudinal axis of the bat, or handle portion of the bat,
can be
accomplished through actual testing or through use of design specifications.
The method
further includes assigning one of the at least two categories to each of the
plurality of
bats based, at least in part, upon either the resistance to bending of the
frame or the
resistance to bending of the handle portion. The method of testing for the
resistance to
bending of the bat frame or the handle portion of the frame is preferably
accomplished
using one of the three, three-point bend stiffness test approaches described
above.
Accordingly, the above-described method facilitates provided the bat that best
fits a
particular player. In other words, the bat can be flex-tuned to a particular
player. For
example, youth baseball bats may be configured with handle portions having a
lower
resistance to bending along the longitudinal axis of the bat than adult
baseball bats. In
other example, the youth baseball bats may be categorized with different
stiffness levels,
or different levels of resistance to bending, in order to appropriately match
a bat to a
particular youth player. One youth model would be stiff, the second less
stiff, and the
third even less stiff, or more flexible.
-27-
CA 02488084 2004-11-19
In constructing the bat of the illustrated embodiment the striking member 12
may
be formed as set out above. End 12b initially remains cylindrical, without the
bent over
portion as illustrated in FIG. 1.
The tubular handle member may be formed by wrapping sheets of
preimpregnated composite material on a mandrel. A first layer is wrapped on
the
mandrel, followed by a second layer, etc., until the desired number of layers
have been
wrapped on the mandrel in the desired positions and orientations to form the
tubular
handle member. The mandrel has a configuration which produces both the
elongate
substantially cylindrical gripping portion 32 and the diverging frusto-conical
juncture
section 34.
To form projecting ribs 40, and referring to Figs. 7-9, after a sufficient
number
of layers of preimpregnated composite material have been wrapped onto the
mandrel, a
plurality of forming members indicated generally at 70, 72, 74 having a
selected arcuate
configuration are placed on the outside of the juncture section of the handle
member
while the composite material is still malleable. FIG. 7 shows members 70, 72,
74 prior
to placement on the outside of the juncture section 34 and the placement of
such is
illustrated in dashed outline in FIG. 7. As is seen members 70, 72, 74 do not
extend
fully about the juncture section when placed thereon, but instead have gaps
therebetween.
Members 70, 72, 74 have a thickness substantially equal to the desired
projection
for ribs 40 and the space between adjacent edges of elements 70, 72, 74 is the
desired
width of ribs 40.
As mentioned previously, the projections may be in forms other than elongate
ribs and other molding or forming members may be provided to achieve the
desired
projection configurations.
When the forming members are placed against the juncture section as noted, the
tubular member then may be wrapped in shrink tape and placed in an oven
between 250
and 300° F for about 45 minutes to one hour. The shrink tape preferably
is temperature
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CA 02488084 2004-11-19
resistant and has high shrinkage and compaction capability when heated. As the
shrink
tape contracts it presses the composite layers into a desired configuration
about the
forming mandrel and presses members 70, 72, 74 into the composite material as
seen in
FIG. 8 to form depressions between areas which become projecting ribs 40. The
depressions are indicated generally at 76, 7$, 80, respectively, having a
depth equal to
the thickness of members 70, 72, 74. FIG. 9 illustrates the configuration thus
produced
when members 70, 72, 74 are removed.
Heating the handle member speeds the curing process, but it may be allowed to
cure at a lower temperature for a longer period of time. For example, the
handle
member may be allowed to cure at room temperature for several days. The
pressure
applied by the shrink tape may range from 15 to 150 psi depending both on the
type of
the shrink tape used and the flow properties of the matrix material used.
Alternately,
some other known apparatus rnay be used to pressurize the handle member during
curing, such as a bladder or a vacuum bag.
The handle member (or striking member if chosen to do so) also may be formed
of a chopped fiber slurry. The chopped fibers can be carbon, glass,
fiberglass, boron,
or various metals.
Although not illustrated in the figures, it should be recognized that other
methods
may be used for forming the handle and providing a desired series of
projections
thereon. One method of doing so is to wrap sheets of pre-impregnated composite
material onto a mandrel as previously described to form the general
configuration for the
handle with its cylindrical gripping portion and flared frusto-conical
juncture section.
The materials wrapped on the mandrel then may be placed in a clam shell style
mold
having the desired external configuration for the handle, including forms to
produce a
selected pattern of projections thereon. After the clam shell mold has been
placed about
the exterior of the handle, the forming mandrel is removed, a pressure bladder
is
inserted where the mandrel previously had been, and pressure is applied on the
bladder
to force the wrapped materials outwardly against the mold. The materials then
are
allowed to cure and are removed from the mold with the desired external
configuration.
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CA 02488084 2004-11-19
Although the handle member has been described using a plurality of sheets of
impregnated composite material, the layers may be formed by some other method,
such
as a filament winding process. With a filament winding process, a continuous
fiber,
rather than a preimpregnated sheet as described above, is wrapped around a
mandrel.
The filament winding process may use a preimpregnated fiber. Alternately, the
continuous fiber may run through a resin bath before it is wrapped onto the
mandrel.
The filament winding process typically winds the fiber in a helical path along
the
mandrel, making it difficult to produce a layer having fibers that are exactly
90 degrees
relative to the longitudinal axis of the layers. Thus the layers may include
layers that are
at an angle substantially 90 degrees, but not exactly at 90 degrees.
The handle member, being produced of composite material, permits selective
production to obtain a handle member of the desired weight while still
obtaining the
necessary strength and stiffness.
In an alternative preferred embodiment, the handle member can be formed of a
I S thermoplastic material, as described above. The handle member formed of a
thermoplastic material is preferably produced through injection molding. The
injection
molding process includes the steps of obtaining a mold having a cavity
configured for
the desired structure, such as the handle member. The mold cavity is then
filled with the
thermoplastic material under heat and pressure. The thermoplastic material can
include
fiber reinforcement, and/or it can be formed of a combination of thermoplastic
materials. The thermoplastic material is then allowed to cure. After curing,
the
structure (the handle member) is removed from the mold. If a fiber-reinforced
thermoplastic material is used, the injection process can be configured to
orientate a
significant portion the fibers, or fiber segments, in a particular direction.
As such, the
handle member formed of a thermoplastic material can be generally anisotropic.
Preferably, the handle member formed of a thermoplastic material is formed to
be
generally isotropic (wherein the fibers, or fiber segments, are randomly
configured).
After the handle member has been formed it is inserted through the open end
12b
of striking member 12, such that gripping portion 32 extends longitudinally
outwardly
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CA 02488084 2004-11-19
from end 12a of the striking member. Prior to inserting the handle member a
layer of
adhesive is applied either to the outer surface of juncture section 34 of the
handle
member or the inner surface of juncture section 14 of the striking member. The
striking
member 12 and handle 30 are urged in opposite directions along the
longitudinal axis,
such that the juncture section 34 of the handle member is forced into tight
engagement
with the interior surface of juncture section 16. As this occurs, the adhesive
applied
between the parts is pressed into recesses 76, 78, 80 and ribs 40, or other
projections,
firmly contact, or engage, the inner surface of juncture section 16. Excess
adhesive will
be allowed to flow outwardly from end 30a of the handle member, with only the
selected
thickness of adhesive remaining.
It has been found that an adhesive such as Scotch-WeIdTM DP-100 epoxy adhesive
or PT 1000 urethane adhesive from Willamette Valley Co., of Eugene, Oregon,
works
well in this application. Other appropriate adhesives also may be used. In a
preferred
embodiment, projections 40 extend outwardly from remainder portions of the
outer
surface of the juncture section of the handle member in a range of 0.001 to
0.010 inch,
and more preferably in a range of 0.002 to 0.005 inch and have a width in a
range of
0.125 to 0.75 inch and more preferably in a range of 0.2 to 0.3 inch. The
layer of
adhesive will have a thickness generally equal to height of the projections
and is allowed
to cure and form a substantially rigid, firm interconnection between the
striking member
and the handle member. The substantially rigid interconnection between the
juncture
sections of the striking member and handle member provided by the adhesive and
direct
engagement of the projections with the inner surface of the striking member
permits
substantially complete striking energy transfer between the handle member and
the
striking member.
After the handle member has been secured to the striking member, insert 22 is
inserted into the striking member, the outer end 12b is rolled over into the
configuration
illustrated in FIG. 1, and stop member 50 is inserted therein. Transition
member 52
(when used) is attached to provide a smooth transition between the inner end
12a of the
striking member and handle 30.
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CA 02488084 2004-11-19
Prior to, or following, assembly of the handle member and striking member,
weighted member, or plug, 54 is inserted and secured in the proximal end
portion of the
handle member as shown in FIG. 1.
Weighted plug 54 is a generally cylindrical member coupled to the proximal end
30b of the handle member 30. The weighted plug preferably is sized to fit
snugly within
the proximal end 30b of the handle member 30 and preferably is affixed to the
proximal
end 30b with a suitable adhesive. Alternative means for coupling the plug 54
to the
proximal end 30b of the handle member 30 also are contemplated, such as, for
example,
press-fit connections, fasteners, and other mechanical latching mechanisms.
The
weighted plug 54 is formed of a relatively dense material, preferably a metal.
Alternatively, the weighted plug 54 can be formed of other materials, such as,
for
example, sand, a fluid or a polymeric material. The plug 54 is formed with a
weight in
the range of 0.5 to 7.0 ounces, and preferably within a range of 2 to 5
ounces, and a
length in the range of 1.0 to 4.0 inches.
I S The weighted plug 54 places additional weight, or mass, generally directly
beneath the player's grip during swinging, thereby facilitating the player's
ability to
swing the bat and to increase his or her bat speed. The weighted plug 54
provides the
player with a pivot point, which facilitates rotation of the bat about the
mass or grip
location of the player.
Additionally, the weighted plug 54 also serves to dampen, or substantially
reduce, the shock, vibration and "sting" commonly felt by a player when
hitting a ball,
particularly when the ball is hit away from a desired hitting region of the
striking
member, or the "sweet spot." The weighted plug 54 serves as a vibration sink
that
substantially lowers the amplitude of the vibrational energy generated upon
impact of the
bat 10 with a ball at the location of the plug 54 thereby reducing the
vibration or shock
felt by the player. In another alternative preferred embodiment, the plug 54
is integrally
formed with the knob 48.
The use of the weighted plug 54 is just one example of the advantages achieved
in the present invention from redistributing the weight, or mass, within the
bat 10
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CA 02488084 2004-11-19
through decoupling of the handle member 30 and the striking member 12. When
forming the handle member 30 of a composite material, the weight of the handle
member 30 can be reduced from that of a conventional metal handle member. This
weight can then be redistributed to other locations on the bat, such as at the
proximal
end of the handle member 30 to improve, or tune, the performance of the bat
10. In the
present invention, the weighted plug 54 can be added to the bat 10 to enable
the player
to increase his or her bat speed, and to reduce the shock and vibration felt
by the user,
without excessively or unnecessarily increasing the weight of the bat 10. In
another
alternative preferred embodiment, weight can be redistributed to the striking
member 12.
The method described herein and the bat produced provide a bat which has
improved striking capabilities. Such improved striking capabilities are
provided by the
structural characteristics of the bat. In one instance increased bat swing
speed is allowed
by producing a bat with a handle which is lighter than would be the case if it
were made
of the same material or in a manner similar to the striking portion of the
bat. This
reduction in weight of the handle in relation to the striking portion and
providing a
substantially rigid interconnection between the two permits increased bat
speed and
substantially complete striking energy transfer between the striking member
and the
handle member. Further it provides desirable weight distribution in the bat
with the
greatest effective mass in the striking region and lower effective mass in the
handle.
It also has been found that the slugging, or hitting, characteristics of the
bat may
be varied by mating various composite handle members with striking members of
different materials or configurations, with a substantially rigid
interconnection
therebetween. Thus different models of bats may be produced, tuned to selected
requirements.
By providing a bat constructed with an independently produced striking member
and handle member which are rigidly interconnected at a juncture region, bats
may be
made with numerous selected functional characteristics. The striking member
may be
made of materials which provide optimum ball striking effectiveness, while the
handle
member may be constructed in such a fashion that is allows the batter to
impart the
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CA 02488084 2004-11-19
maximum possible force from the batter's hands to the bat and to produce the
greatest
swing speed. The handle member may be laid up from a variety of composite
materials
with selected thicknesses, orientations, and positions within the handle
member to
produce desired strength, weight, stiffness, etc., in the overall handle or
even within
selected regions of the handle.
Explaining further, selected regions of the handle may have a greater or
lesser
number of layers of composite material than other regions, the thicknesses or
structural
materials within the layers may vary at different regions of the handle
member, and
other characteristics may be varied through selected lay up of materials in
the handle
member during production.
As an example of desirable differences in handle members which may be formed,
it has been found that certain bats, such as for softball use, will work
better with a stiffer
handle member, whereas for baseball a more flexible, or less stiff, handle
member is
preferable.
With the structure and method for producing such set out herein, a bat may be
optimized for the selected usage by selection of materials and lay up for the
various
components of the bat.
While there have been illustrated and described preferred embodiments of the
present invention, it should be appreciated that numerous changes and
modifications may
occur to those skilled in the art and it is intended in the appended claims to
cover all of
those changes and modifications which fall within the spirit and scope of the
present
invention.
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