U.S. patent application number 12/704453 was filed with the patent office on 2011-08-11 for ball bat having a segmented barrel.
Invention is credited to Dewey Chauvin.
Application Number | 20110195808 12/704453 |
Document ID | / |
Family ID | 44354157 |
Filed Date | 2011-08-11 |
United States Patent
Application |
20110195808 |
Kind Code |
A1 |
Chauvin; Dewey |
August 11, 2011 |
BALL BAT HAVING A SEGMENTED BARREL
Abstract
A ball bat includes a segmented or decoupled barrel, which
reduces the axial stiffness and BBCOR of the barrel, while
providing little or no increase in the bat's moment of inertia.
Segmenting the barrel, alone or in combination with other
performance-reducing features, may be used to lower the BBCOR (or
other specified performance characteristic) of the ball bat below
the performance limits of a given regulatory association or other
governing body.
Inventors: |
Chauvin; Dewey; (Simi
Valley, CA) |
Family ID: |
44354157 |
Appl. No.: |
12/704453 |
Filed: |
February 11, 2010 |
Current U.S.
Class: |
473/564 |
Current CPC
Class: |
A63B 59/50 20151001;
A63B 60/08 20151001; A63B 2102/18 20151001; A63B 59/51 20151001;
A63B 60/54 20151001; A63B 2209/10 20130101 |
Class at
Publication: |
473/564 |
International
Class: |
A63B 59/06 20060101
A63B059/06 |
Claims
1. A ball bat including a handle connected to a barrel in an axial
direction, with the barrel comprising: a radially inner wall; a
layer of a first adhesive material on a radially outer surface of
the radially inner wall; a plurality of circumferential, radially
outer segments adhered to the radially inner wall via the first
adhesive material, wherein the radially outer segments are spaced
apart from one another in the axial direction; and a second
adhesive material adhering the radially outer segments to one
another in the axial direction.
2. The ball bat of claim 1 wherein radially outer surfaces of the
radially outer segments are flush with one another.
3. The ball bat of claim 1 wherein the ball bat includes a tapered
section between the barrel and the handle in the axial direction,
and wherein the radially inner wall is not in contact with the
tapered section or the handle of the ball bat.
4. The ball bat of claim 1 wherein the ball bat includes a tapered
section between the barrel and the handle in the axial direction,
and wherein one end of the radially inner wall is integral with the
tapered section, while a substantial portion of the radially inner
wall is recessed relative to the tapered section.
5. The ball bat of claim 1 wherein the radially outer segments are
spaced apart from one another in the axial direction by
approximately 0.02 to 0.06 inches.
6. The ball bat of claim 1 wherein the layer of the first adhesive
material has a thickness of approximately 0.02 to 0.06 inches.
7. The ball bat of claim 1 wherein the first and second adhesive
materials comprise the same material.
8. The ball bat of claim 1 wherein the first and second adhesive
materials comprise elastomeric adhesive materials.
9. The ball bat of claim 1 wherein the barrel includes four to six
radially outer segments.
10. The ball bat of claim 1 further comprising a radially innermost
wall attached to or in engagement with a radially inner surface of
the radially inner wall.
11. A ball bat including a handle connected to a barrel in an axial
direction, with the barrel comprising: a radially inner initial
segment; a first multi-plane segment including a radially outer
portion adhered to a radially outer surface of the initial segment,
and a radially inner portion axially adjacent to the initial
segment; at least one additional multi-plane segment, wherein each
additional multi-plane segment includes a radially outer portion
adhered to a radially outer surface of a radially inner portion of
a previous multi-plane segment, and a radially inner portion
axially adjacent to the radially inner portion of the previous
multi-plane segment; and a radially outer segment adhered to a
radially inner portion of the last of the additional multi-plane
segments.
12. The ball bat of claim 11 wherein the ball bat includes a
tapered section between the barrel and the handle in the axial
direction, and wherein the initial segment is integral with the
tapered section.
13. The ball bat of claim 11 wherein the radially outer segment is
connected to or integral with a cap at a free end of the
barrel.
14. The ball bat of claim 11 wherein an elastomeric adhesive
material is used to adhere the segments to one another.
15. The ball bat of claim 14 wherein the elastomeric adhesive
material has a thickness of approximately 0.02 to 0.06 inches.
16. The ball bat of claim 11 wherein the radially outer portions of
the multi-plane segments and the radially outer segment are spaced
apart from one another in the axial direction by approximately 0.02
to 0.06 inches.
17. The ball bat of claim 11 wherein the radially outer portions of
the multi-plane segments and the radially outer segment have
radially outer surfaces that are flush with one another.
18. The ball of claim 11 wherein the barrel includes three
multi-plane segments.
19. The ball bat of claim 11 further comprising a radially
innermost wall attached to or in engagement with at least one of
the radially inner segment and the radially inner portions of the
multi-plane segments.
20. A ball bat including a handle connected to a barrel in an axial
direction, with the barrel comprising: a plurality of radially
outer rings spaced apart from, and adhered to, one another in the
axial direction, wherein radially outer surfaces of the radially
outer rings provide an external hitting surface; and a radially
inner wall adhered to the plurality of radially outer rings.
Description
BACKGROUND
[0001] Baseball and softball governing bodies have imposed various
performance limits on ball bats with the goal of regulating batted
ball speeds. Each association generally independently develops
various standards and methods to achieve a desired level of play.
Bat designers typically comply with these performance standards by
adjusting the performance, or bat-ball coefficient of restitution
("BBCOR"), of their bat barrels. Typical methods of controlling
BBCOR include thickening the barrel wall of a hollow metal bat, or
increasing the radial stiffness of a composite bat via the
selection of specific materials and fiber angles.
[0002] A composite bat's radial stiffness and fiber orientations
are limited, however, by a given material thickness. The barrel
walls in composite bats, therefore, are also often thickened to
provide additional stiffness, which in turn limits BBCOR and barrel
performance.
[0003] Thickening a barrel wall generally increases the bat's
weight and, more importantly, it's "swing weight" or moment of
inertia ("MOI"). MOI is the product of: (a) a mass, and (b) the
square of the distance between the center of the mass and the point
from which the mass is pivoted. Mathematically, this is expressed
as follows:
MOI=.SIGMA.Mass.times.(Distance).sup.2
[0004] Accordingly, the MOI dictates that it becomes increasingly
difficult to swing a bat as the bat's mass increases or as the
center of the bat's mass moves farther from the pivot point of the
swing (i.e., farther from the batter's hands). Because thickening
the barrel wall increases the bat's weight at a region relatively
distal from the batter's hands, doing so also increases the bat's
MOI. Thus, while thickening a barrel wall may effectively stiffen
the barrel and reduce its performance, the consequent increase in
MOI is generally undesirable for batters.
SUMMARY
[0005] A ball bat includes a segmented or decoupled barrel, which
reduces the axial stiffness and BBCOR of the barrel, while
providing little or no increase in the bat's moment of inertia.
Other features and advantages will appear hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] In the drawings, wherein the same reference number indicates
the same element throughout the views:
[0007] FIG. 1 is a perspective view of a ball bat, according to one
embodiment.
[0008] FIG. 2 is a side-sectional view of a ball bat including a
segmented barrel, according to one embodiment.
[0009] FIG. 2A is a magnified view of Section A of FIG. 2.
[0010] FIG. 3 is a side-sectional view of a ball bat including a
segmented barrel, according to another embodiment.
[0011] FIG. 3A is a magnified view of Section B of FIG. 3.
[0012] FIG. 4 is a side-sectional view of a ball bat including a
segmented barrel, according to another embodiment.
[0013] FIG. 4A is a magnified view of Section C of FIG. 4.
DETAILED DESCRIPTION OF THE DRAWINGS
[0014] Various embodiments of the invention will now be described.
The following description provides specific details for a thorough
understanding and enabling description of these embodiments. One
skilled in the art will understand, however, that the invention may
be practiced without many of these details. Additionally, some
well-known structures or functions may not be shown or described in
detail so as to avoid unnecessarily obscuring the relevant
description of the various embodiments.
[0015] The terminology used in the description presented below is
intended to be interpreted in its broadest reasonable manner, even
though it is being used in conjunction with a detailed description
of certain specific embodiments of the invention. Certain terms may
even be emphasized below; however, any terminology intended to be
interpreted in any restricted manner will be overtly and
specifically defined as such in this detailed description
section.
[0016] Where the context permits, singular or plural terms may also
include the plural or singular term, respectively. Moreover, unless
the word "or" is expressly limited to mean only a single item
exclusive from the other items in a list of two or more items, then
the use of "or" in such a list is to be interpreted as including
(a) any single item in the list, (b) all of the items in the list,
or (c) any combination of items in the list.
[0017] Turning now in detail to the drawings, as shown in FIG. 1, a
baseball or softball bat 10, hereinafter collectively referred to
as a "ball bat" or "bat," includes a handle 12, a barrel 14, and a
tapered section 16 joining the handle 12 to the barrel 14. The free
end of the handle 12 includes a knob 18 or similar structure. The
barrel 14 is preferably closed off by a suitable cap 20 or plug.
The interior of the bat 10 is preferably hollow, allowing the bat
10 to be relatively lightweight so that ball players may generate
substantial bat speed when swinging the bat 10. The ball bat 10 may
be a one-piece construction or may include two or more separate
attached pieces (e.g., a separate handle and barrel), as described,
for example, in U.S. Pat. No. 5,593,158, which is incorporated
herein by reference.
[0018] The ball bat 10 is preferably constructed from one or more
composite or metallic materials. Some examples of suitable
composite materials include fiber-reinforced glass, graphite,
boron, carbon, aramid, ceramic, Kevlar, or Astroquartz.RTM..
Aluminum or another suitable metallic material may also be used to
construct the ball bat 10. A ball bat including a combination of
metallic and composite materials may also be constructed. For
example, a ball bat having a metal barrel and a composite handle,
or a composite barrel and a metal handle, may be used in the
embodiments described herein.
[0019] The ball bat 10 may have any suitable dimensions. The ball
bat 10 may have an overall length of 20 to 40 inches, or 26 to 34
inches. The overall barrel diameter may be 2.0 to 3.0 inches, or
2.25 to 2.75 inches. Typical ball bats have diameters of 2.25,
2.625, or 2.75 inches. Bats having various combinations of these
overall lengths and barrel diameters, or any other suitable
dimensions, are contemplated herein. The specific preferred
combination of bat dimensions is generally dictated by the user of
the bat 10, and may vary greatly between users.
[0020] The ball striking area of the bat 10 typically extends
throughout the length of the barrel 14, and may extend into the
tapered section 16 of the bat 10. For ease of description, this
striking area will generally be referred to as the "barrel"
throughout the remainder of the description. Accordingly, the
handle may be referred to as being connected to the barrel directly
or indirectly via a tapered section.
[0021] A bat barrel 14 generally includes a maximum performance
location or "sweet spot," which is the impact location where the
transfer of energy from the bat 10 to a ball is maximal, while the
transfer of energy to a player's hands is minimal. The sweet spot
is generally located at the intersection of the bat's center of
percussion (COP) and its first three fundamental nodes of
vibration. This location, which is typically about 4 to 8 inches
from the free end of the barrel 14, does not move when the bat is
vibrating in its first (or fundamental) bending mode.
[0022] The bat barrel 14 in the embodiments described herein
preferably includes a radially outer wall that is segmented or
decoupled in the axial direction such that longitudinally or
axially neighboring barrel segments or rings are substantially or
completely isolated from one another. The neighboring barrel
segments may be spaced from one another by any suitable distance,
for example, between approximately 0.02 to 0.06 inches, preferably
approximately 0.04 inches. The spaces between the neighboring
barrel segments are preferably filled with an adhesive material,
such as an elastomeric adhesive of rubber, urethane, foam,
Surlyn.RTM. or the like, such that the neighboring barrel segments
are bonded to one another. The radially outer surfaces of the
neighboring barrel segments, and the interspersed adhesive, are
preferably flush with one another to provide a smooth, continuous
hitting surface.
[0023] Segmenting the barrel in this manner reduces the axial
stiffness of the barrel, which lowers the barrel's performance,
surprisingly even when the barrel includes multiple walls. The
barrel may be segmented into any suitable number of sections or
rings to meet the performance requirements of a given regulatory
association or other governing body. For example, a barrel may
include four to six segments or rings.
[0024] As shown in FIGS. 2 and 2A, a ball bat includes a barrel
having an outer barrel wall 30 and an inner barrel wall 32. The
outer and inner walls are preferably bonded together with an
elastomeric adhesive, such as one of those described above, or via
another suitable bonding material. In one embodiment, the outer and
inner walls are bonded together via a relatively thick elastomeric
layer 34, as described, for example, in U.S. Pat. No. 6,663,517,
which is incorporated herein be reference. The elastomeric layer 34
may, for example, have a thickness of approximately 0.02 to 0.06
inches, preferably approximately 0.04 inches.
[0025] Slices or cuts are made through the outer barrel wall 30 and
preferably terminate at the elastomeric layer 34, resulting in an
outer wall made up of multiple isolated barrel segments 36, 38, 40,
42, 44 or ring-like structures. The spaces between the neighboring
barrel segments are preferably filled with an adhesive material 46,
such as one of the elastomeric adhesives described above.
[0026] As shown in FIGS. 3 and 3A, in another embodiment, multiple
multi-plane barrel segments, including radially external and
internal portions, are adhered to one another to form a fully
segmented barrel (i.e., both the inner and outer barrel walls are
segmented). An internal initial barrel segment 50 preferably
originates at or near, and merges or is otherwise integral with,
the external tapered section 16 of the ball bat. An external
portion 51 of a first multi-plane barrel segment 52 is adhered to
the initial barrel segment 50 via a suitable adhesive 54, such as
one of the elastomeric adhesives described above. Accordingly, the
initial barrel segment 50 provides radial support for the external
portion 51 of the first multi-plane barrel segment 52.
[0027] An internal portion 53 of the first multi-plane barrel
segment 52, similarly, is adhered to an external portion 55 of a
second multi-plane barrel segment 56 via another layer of adhesive
58, such that the internal portion 53 provides radial support for
the external portion 55. Following this pattern, an internal
portion 57 of the second multi-plane barrel segment 56 is adhered
to an external portion 59 of the next successive multi-plane barrel
segment 60 via another layer of adhesive 61. This pattern continues
until an external final barrel segment 62, which engages or is
secured to the cap 20 (or which could be used to form the cap
itself) of the ball bat, is reached. The pattern could
alternatively be reversed, such that the internal initial barrel
segment is located at the cap-end of the barrel and the external
final barrel segment is located adjacent to the tapered section of
the ball bat.
[0028] As shown in FIGS. 4 and 4A, in another embodiment, the
barrel includes a recessed section 70 in the hitting zone having a
reduced diameter relative to the neighboring tapered section 16 of
the ball bat. One end 71 of the recessed section 70 preferably
merges or is integral with the tapered section 16. The radially
outer surface of the recessed section 70 is preferably coated or
covered with a layer of elastomeric adhesive 72 or another suitable
bonding material. External barrel segments 74, 76, 78, 80, 82 or
rings are adhered to the recessed section 70 via the elastomeric
layer 72 (and are spaced apart from one another such that they are
substantially or completed isolated from one another).
[0029] The spaces between the neighboring barrel segments are
preferably filled with an adhesive material 84, such as one of the
elastomeric adhesives described above, such that the neighboring
barrel segments are bonded to one another. The cap-end 86 of the
barrel preferably has an increased diameter relative to the
recessed section 70 such that its radially outer surface is flush
with the neighboring external barrel segment 82.
[0030] Assuming all other features are essentially equal (e.g.,
wall thickness, elastomeric adhesive used, and so forth), the
performance and durability would generally vary between the bats of
the above described embodiments. For example, the ball bat shown in
FIGS. 2 and 2A would generally exhibit lower performance (i.e.,
lower BBCOR) and durability than would the ball bat shown in FIGS.
4 and 4A. This is largely due to the rigidity of the supporting
frame provided by the integral recessed section 70 in the
embodiment shown in FIGS. 4 and 4A.
[0031] As a result, players would generally experience more
feedback, or vibrations, from this more rigid bat during a hit,
particularly when contact occurs away from the sweet spot of the
barrel. Such a ball bat may be desirable to more skilled players
who want feedback to tell them how well they struck the ball.
Lesser skilled players, conversely, generally tend to prefer the
increased isolation between the inner barrel wall 32 and the handle
12 provided by the ball bat shown in FIGS. 2 and 2A, which lessens
the sting felt during hits away from the sweet spot.
[0032] The fully segmented ball bat shown in FIGS. 3 and 3A, in
which barrel segments overlap with neighboring barrel segments,
generally provides the least amount of axial connectivity to the
handle, i.e., the lowest axial stiffness, of the described
embodiments. Accordingly, the ball bat of this embodiment generally
exhibits the lowest performance, or BBCOR, of the described ball
bats. The lack of rigidity and connectivity to the handle lowers
the effective mass of the bat impacting the ball, i.e., the bat
barrel at the point of impact is isolated from the rest of the bat
due to the lack of axial stiffness. Accordingly, players will
generally feel less feedback in this ball bat than in the other
described embodiments.
[0033] The durability and performance of the ball bats described
herein may be modified based on the elastomeric materials used in
the bat barrel. As understood by those skilled in the art of bat
design, properties such as damping, adhesion, and long-term
durability of the ball bat may be affected by the choice of
elastomeric material. Rubbers, for example, tend to exhibit
relatively low damping characteristics but have relatively high
densities and may not have sufficient tear strength to offer a
highly flexible system. Also, adhesion to metal can be very high
when using rubber if vulcanization is used to adhere components to
one another.
[0034] Urethane provides higher damping than many rubbers and comes
in a form that is generally easier to use in a variety of assembly
processes. Silicone or foamed elastomers may be used, as well.
Foamed elastomers, while generally lighter in weight, tend to have
lower tear strength and exhibit higher damping than fuller-density
elastomers. Foamed elastomers may work well in the ball bats shown
in FIGS. 4 and 4A, for example, but, due to their lower tear
strength, may not work as well in the more fully segmented ball bat
shown in FIGS. 3 and 3A. Adding fibers strands to the elastomer
could provide increased tear resistance, however.
[0035] In general, elastomeric materials having a lower coefficient
of restitution ("COR") will provide a ball bat with less rebound
performance. Changing the durometer of the elastomeric material
could also affect rebound performance, depending on the stiffness
of the overall bat barrel and the hardness of the ball. In general,
the lower the durometer of the elastomer, the higher the ball
rebound performance, as long as the COR of the elastomer is not
decreased. The COR of an elastomer, however, commonly decreases as
its durometer decreases. Thus, a bat designer must take into
consideration the properties of the specific elastomer being
used.
[0036] Segmenting the barrel creates an extreme shift in the
stiffness of the barrel. Indeed, the outer barrel wall (and
optionally the inner barrel wall) is effectively decoupled from the
handle of the bat. This lack of stiffness causes larger deflections
and much lower frequency responses in the bat than in bats not
having a segmented barrel. The dramatic decrease in bat frequency
response decouples or mistimes the bat rebound response to the ball
rebound response. This effect is similar to a trampoline that
flexes back to shape after the jumper has left the canvas surface.
By segmenting the barrel, the axial stiffness becomes low enough
that the ball rebound is significantly reduced. The amount of ball
rebound lost depends upon how slow the bat recovers. In general,
decreasing the stiffness of a body lowers the frequency response of
the body, i.e., a more flexible bat barrel is slower to
respond.
[0037] A ball bat having a segmented barrel not only helps to
control ball rebound performance, but also generally reduces sting
experienced by players when a ball impacts the bat away from the
sweet spot of the barrel. This is because the lack of axial
stiffness limits the transmission of vibration energy down the
length of the bat to the player's hands. Further, most elastomeric
adhesives or other flexible adhesive materials typically are highly
damped, which further reduces the sting felt when a ball strikes
the barrel away from the sweet spot.
[0038] As discussed, axially segmenting the bat barrel generally
reduces its durability. This can be compensated for by slightly
increasing the thickness of the barrel walls, avoiding stress
risers (e.g., sharp edges, corners, and so forth) in the bat
design, or sufficiently supporting the inner barrel wall to prevent
excessive deflection. In any of the described embodiments, for
example, an additional, radially innermost barrel wall may be
attached to or in engagement with a radially inner surface of the
radially inner barrel wall to provide additional strength and
durability to the ball bat. The additional wall could be made of a
rigid material (e.g., aluminum, magnesium, titanium, or some
fiber-reinforced plastic materials), or of a semi-rigid material
(e.g., thermoplastic, some other fiber-reinforced plastic
materials, or an additional layer of elastomeric material, which
may optionally include reinforcing fibers). The inclusion of an
additional barrel wall may be particularly useful in the fully
segmented ball bat shown in FIGS. 3 and 3A.
[0039] It was initially expected that a segmented barrel would
provide improved ball rebound performance. This expectation was
generally based on the observation that double-wall bats are more
flexible than single-wall bats. Similarly, bats including an
elastomeric core are generally more flexible than single-wall bats.
Thus, it was believed that making the bat even more flexible would
improve barrel performance. This was not the case. In fact, it was
found that a double-wall bat having a segmented barrel generally
provides significantly lower rebound performance than does a
typical, unsegmented single-wall ball bat made of similar materials
and having similar dimensions. Accordingly, a segmented barrel may
be utilized, alone or in combination with other
performance-reducing features, to reduce a ball bat's BBCOR (or
other specified performance characteristic) below the limits
imposed by regulatory associations or governing bodies, while
providing little or no increase in the bat's moment of inertia.
[0040] Any of the above-described embodiments may be used alone or
in combination with one another. Furthermore, the ball bat having a
segmented barrel may include additional features not described
herein. While several embodiments have been shown and described,
various changes and substitutions may of course be made, without
departing from the spirit and scope of the invention. The
invention, therefore, should not be limited, except by the
following claims and their equivalents.
* * * * *