U.S. patent number 3,811,596 [Application Number 05/255,895] was granted by the patent office on 1974-05-21 for ball bat construction.
This patent grant is currently assigned to Aluminum Company of America. Invention is credited to Richard C. Wilson.
United States Patent |
3,811,596 |
Wilson |
May 21, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
BALL BAT CONSTRUCTION
Abstract
An end plug for a hollow ball bat. The end plug has a
substantially rigid inner plug member and a resiliently
compressible outer plug member secured to the inner member. The
outer plug member has a periphery provided with a generally
cylindrical lower portion and an upper portion separated from the
lower portion by an outwardly open annular recess. The inner plug
member has a generally radially outwardly directed stabilizer
portion which extends radially outwardly at least to a position
adjacent to the periphery of the outer plug member. The outwardly
directed stabilizer portion of the inner plug member may be divided
into a plurality of individual stabilizer segments and may be
provided with underlying reinforcing members. A hollow ball bat
having a generally cylindrical barrel portion and a generally
cylindrical handle portion. At least one of the barrel and handle
portions terminating in an open end provided with a transversely
inwardly directed flange which is engaged within the annular recess
of the end plug to provide an effective mechanical joint between
the bat and the end plug. The composite end plug serves to provide
both sound and vibration deadening means and integral structural
reinforcing means resisting relative axial movement between the end
plug and the ball bat.
Inventors: |
Wilson; Richard C. (Arcadia,
CA) |
Assignee: |
Aluminum Company of America
(Pittsburgh, PA)
|
Family
ID: |
26819708 |
Appl.
No.: |
05/255,895 |
Filed: |
May 22, 1972 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
121677 |
Mar 8, 1971 |
3703290 |
|
|
|
Current U.S.
Class: |
220/315; 220/378;
473/564; 220/DIG.19 |
Current CPC
Class: |
A63B
60/54 (20151001); A63B 59/51 (20151001); A63B
59/50 (20151001); A63B 2102/18 (20151001); Y10S
220/19 (20130101) |
Current International
Class: |
A63B
59/00 (20060101); A63B 59/06 (20060101); B65d
051/00 (); A63b 059/06 () |
Field of
Search: |
;220/29,39R,24R,42B,60,DIG.19,24A,59 ;215/48 ;273/72R,72A |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
15,520 |
|
1895 |
|
GB |
|
412,946 |
|
1910 |
|
FR |
|
1,054,947 |
|
Apr 1959 |
|
DT |
|
570,621 |
|
Dec 1957 |
|
IT |
|
Primary Examiner: Lowrance; George E.
Assistant Examiner: Shoap; Allan N.
Attorney, Agent or Firm: Silverman; Arnold B.
Parent Case Text
This is a division of application Ser. No. 121,677, filed Mar. 8,
1971 now U.S. Pat. No. 3,703,290.
Claims
1. An end plug for a hollow ball bat, comprising
a substantially rigid inner plug member,
a resiliently compressible outer plug member secured to said inner
plug member,
said outer plug member having a lower portion and an upper portion
separated from said lower portion by an outwardly open annular
recess formed solely within said outer plug member,
said recess being disposed closer to the upper extremity of said
outer plug member than to the lower extremity of said outer plug
member,
said upper portion of said outer plug member substantially
completely covering the upper surface of said inner plug
member,
said lower portion of said outer plug member having a generally
cylindrical peripheral configuration,
said lower portion of said outer plug member having a greater
average diameter than said upper portion of said outer plug member,
and
said inner plug member having a generally radially outwardly
directed stabilizer portion extending radially outwardly at least
to a position adjacent to the periphery of said outer plug member,
whereby said end plug may be mechanically secured to a tubular ball
bat body to establish a permanent joint therebetween and provide
improved sound and vibration
2. The end plug of claim 1, wherein
said generally radially outwardly directed stabilizer portion of
said inner plug member is divided into at least four individual
segments, and
said stabilizer segments extend angularly upwardly and radially
outwardly
3. The end plug of claim 1, wherein
said generally radially outwardly directed stabilizer portion of
said inner plug member has a circumferentially substantially
continuous circular
4. The end plug of claim 3, wherein
said stabilizer portion has a plurality of openings disposed
intermediate
5. The end plug of claim 2, wherein
said annular recess in said outer plug member is defined by an
upper annular recess defining surface which is upwardly and
radially outwardly directed and a lower annular recess defining
surface which is downwardly and radially outwardly directed,
said radially outwardly directed stabilizer segments of said innner
plug member have outer extremities terminating at a position not
higher than said lower annular recess defining surface, and
said radially outwardly directed stabilizer portion extending
radially outwardly at least to a position closely adjacent to the
periphery of said
6. The end plug of claim 5, wherein
said inner plug member is a unitary molded element, and
said outer plug member is a unitary molded element molded around
said inner
7. The end plug of claim 6, wherein
said inner plug member is composed of material selected from the
group consisting of impact styrene, brass, steel and aluminum
and
said outer plug member is composed of a material selected from the
group
8. The end plug of claim 5, wherein
said inner plug member has an inner tubular core having a closed
upper end,
said inner plug member has a generally cylindrical body portion
spaced radially outwardly from said tubular core,
connecting means securing said inner tubular core to said
cylindrical body portion, and
said radially outwardly directed stabilizer portion extending
outwardly
9. The end plug of claim 8, including
said radially outwardly directed stabilizer portion extending
circumferentially around said cylindrical body portion at a
position spaced upwardly from the bottom of said cylindrical body
portion, and
a plurality of integral reinforcing elements extending radially
outwardly from said cylindrical body portion in underlying
supporting contact with respect to said radially outwardly directed
stabilizer portion of said inner plug member.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an aluminum ball bat construction and
more specifically to a composite end plug which is adapted to be
mechanically joined to a ball bat to establish a stable joint and
to provide a bat with sound and vibration dampening properties.
2. Description of the Prior Art
It has been known to provide hollow metal bat structures having
various configurations and composed of a wide range of materials.
In general, the bat bodies have been formed from metal tube stock
which has been worked, as by swaging, to establish a relatively
small diameter handle portion, a relatively large diameter barrel
or impact portion and a tapered intermediate portion. It has been
known to employ metal end caps to close the opposed open ends of
the bat body. See U. S. Pat. No. 1,499,128. These structures not
only failed to provide the desired sound and vibration dampening in
order to reduce both undesirable noise and bat vibration, but also
cumbersome and expensive fabricating techniques were required in
order to effect the joint.
It has also been known to provide such a hollow metal bat structure
wherein an end plug composed of a homogeneous rubberous material
has been provided. See U. S. Pat. No. 3,479,030. Such plugs have
been secured to the bat body by the use of a separate adhesive
material such as an epoxy. One of the difficulties with such a
construction is the need to rely on the adhesive as the primary or
sole plug retaining means on a product which is subjected to
substantial mechanical shock in ordinary use. In addition, the
circumferential uniformity of such a joint cannot be readily
assured. Finally, the economic aspects of the production cycle are
distorted somewhat as a result of the need to provide and apply the
adhesive and subsequently insert the adhesive carrying plug into
the bat opening without spillage.
There remains, therefore, the problem of providing a ball bat plug
and bat assembly construction which facilitates providing a
permanent effective joint between the bat and plug. In addition,
there is lacking such a joint which provides sound and vibration
dampening while also providing for maximum resistance to mechanical
shock. The exposed materials must be such as to provide resistance
to mechanical wear and also to tolerate the repeated exposure to
all sorts of weather and soil conditions which the ball bat would
encounter during normal usage, without loss of these desirable
properties.
SUMMARY OF THE INVENTION
The above-described problems have been solved by the bat plug and
bat construction of this invention.
This invention provides a composite end plug adapted for insertion
into and joinder to either the barrel end, the handle end or both
ends of a ball bat. The composite plug has a substantially rigid
inner plug member and a resiliently compressible outer plug member
secured to the inner plug member. The outer plug has a lower
portion and an upper portion separated from the lower portion by an
annular recess which is adapted to receive and be interengaged with
a transversely inwardly directed flange which defines an opening in
the end of the bat. The lower portion preferably has a generally
cylindrical outer periphery. The inner plug member has a generally
radially outwardly directed stabilizer portion which extends to or
closely adjacent to the periphery of the outer plug member. This
outwardly directed portion may be segmented and is preferably
angularly upwardly and radially outwardly directed.
Among the preferred materials for use in the inner plug member are
impact styrene, brass, steel and aluminum. Among the preferred
materials for use in the outer plug member are polyvinyl chloride,
polyethylene and rubber. The end plug may conveniently be formed by
first providing a unitary molded inner plug member and subsequently
molding the outer plug member therearound.
The inner plug member preferably has a tubular inner core having a
closed upper end and a cylindrical body portion spaced radially
outwardly from the tubular core. Connecting means secure the
tubular core to the body portion and the radially outwardly
directed stabilizer portion extends outwardly from the cylindrical
body portion. Reinforcing means may be provided for the radially
outwardly directed stabilizer portion. Also, the radially outwardly
directed stabilizer portions preferably approach the periphery of
the outer plug member at a position not higher than the lower of
the two annular surfaces which cooperate to define the annular end
plug recess.
The hollow bat has an enlarged hollow passageway at the barrel end
which terminates in an end opening defined by a generally radially
inwardly directed flange. The handle end may be provided with a
similar opening. The flange is received within the annular recess
of the plug member in order to provide an interlocking joint which
resists relative axial separation of the plug from the bat. The
diameter of the radially outwardly directed stabilizer portion of
the plug member approximates the diameter of the inner surface of
the bat at that location of the bat which is adjacent the outer
extremity of the stabilizer element. In a preferred form, the
outwardly directed stabilizer element is in physical contact with
the inner surface of the bat and resists relative axial movement of
the plug with respect to the bat. In addition, the diameter of the
inner plug member is preferably greater than the diameter of the
opening defined by the flange in the end of the bat in which the
end plug is secured.
It is an object of this invention to provide an end plug for a
hollow ball bat adapted to provide an effective mechanical joint
between the hollow ball bat and the plug, which joint is of
sufficient strength to withstand the severe mechanical shock
encountered in ordinary use of the ball bat, while resisting
undesired relative axial movement of the end plug with respect to
the bat body.
It is another object of this invention to provide an end plug
member for joinder to a hollow ball bat which plug has a
substantially rigid inner member and a compressible outer member
secured thereto in order to provide effective mechanical retention
of the end plug and effective sound and vibration dampening for the
bat assembly.
It is another object of this invention to provide a composite bat
plug structure which may effectively be fabricated by initial
unitary molding of the inner plug member followed by subsequent
molding of a unitary outer plug member therearound.
It is another object of this invention to provide a bat structure
which has an effective mechanical joint between a bat plug element
and a bat element such that the plug will effectively by
mechanically retained in position during normal bat usage and that
all exposed portions of the bat assembly are adapted to withstand
both physical wear and exposure to the various outdoor climates and
soil conditions in which the bat will normally be used.
These and other objects of this invention will be more fully
understood from the following description of the invention on
reference to the illustrations appended hereto.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view, partially broken away, of a form of
ball bat construction contemplated by this invention.
FIG. 2 is an elevational view of one form of composite end plug
contemplated by this invention.
FIG. 3 is a sectional view taken through 3--3 of FIG. 2
FIG. 3A is an enlarged detailed illustration of a portion of a
joint of this invention.
FIG. 3B illustrates a modified form of mechanical joint of this
invention.
FIG. 4 illustrates a top plan view of a modified form of inner plug
member contemplated by this invention.
FIG. 5 is an elevational view, partially broken away, of the inner
plug member shown in FIG. 4.
FIG. 6 is a bottom plan view of the inner element shown in FIG.
4.
FIG. 7 illustrates a top plan view of a form of inner plug member
with a stabilizer portion having a generally continuous ring-shaped
configuration.
FIG. 8 is a top plan view of a modified form of inner plug member
similar to that shown in FIG. 7, except for the presence of
openings within the stabilizer portion.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now more specifically to FIG. 1, there is shown a hollow
ball bat construction of a type contemplated by this invention. In
the particular form shown, the ball bat is metal and has a handle
portion 2, a barrel portion 4 and a connecting tapered portion 6.
The handle portion 2 terminates in a knob 8 and is preferably
covered by an appropriate grip portion 7. In the form shown, the
knob 8 is a separate plug element which extends into the open end
of hollow handle 2 and is mechanically secured thereto. The barrel
portion 4 terminates in an open end which is closed by a plug
10.
For convenience of description, the discussion of the novel plug
assembly of this invention will center around plug 10 which is
secured to barrel portion 4. It will be appreciated, however, that
a composite plug having the same or substantially identical
features may be employed for knob 8 which is inserted within and
secured to hollow handle 2.
Referring now to FIGS. 2 and 3, one preferred form of plug
construction will be considered. The plug of this invention has an
outer plug element 16 and an inner plug element 18. The outer plug
element 16, in this form, has a lower portion 20 and an upper
portion 22 which is separated from lower portion 20 by annular
recess 24. The lower portion 20 has a generally cylindrical
peripheral configuration. The portion of the outer plug element 16
disposed below the annular recess 24 has a greater average diameter
than the portion of the outer plug element disposed above annular
recess 24. The annular recess is defined by upper annular surface
26 and lower annular surface 28. The recess is disposed closer to
the upper extremity of the outer plug element 16 than to the lower
extremity thereof. Flange 30, in this figure, has a generally
perpendicular orientation with respect to the adjacent bat body
portion.
In the form illustrated, the outer plug element 16 is preferably
composed of a resiliently compressible material such as a plastic
or rubber material with a polyvinyl chloride being preferred. As
the hardness of the outer plug element material selected is
increased, the wear resistance of exposed surface 22 is improved.
As the compressibility of the outer plug element material selected
is increased, improved dampening characteristics are produced. The
inner plug element 18 is preferably composed of a substantially
rigid material such as impact styrene which is preferred. In the
alternative, an appropriate metal such as steel, aluminum and brass
may be employed. An effective form of impact styrene employed for
this usage has a tensile strength of about 65,000 lb/in.sup. 2 and
a compressive strength of about 9,300 lb/in.sup.2. An effective
polyvinyl chloride material for this use has been found to have a
tensile strength of about 2,400 lb/in.sup.2. The inner plug member
18 serves as a reinforcing member which resists undesired relative
axial movement between plug 10 and barrel 4 after the joint between
the two has been established. The outer plug member 16 serves to
deaden sound and vibrations. In addition, the upper portion 22,
which in the form shown is upwardly domed, serves as a shock
absorbing end cap which prevents damage to the bat structure when
that portion is subjected to physical contact with the earth or
other objects during normal usage and handling. The upper portion
of outer plug element 16 substantially completely covers the upper
surface of the inner plug element 18.
The word "flange" as used herein shall refer to any generally
radially inwardly deformed portion of a hollow bat adjacent or at
an end of the bat body which defines a restricted opening therein
and includes portions which are integrally reinforced as by
providing a hollow bead or reentrant fold.
A form of joint between barrel portion 4 and outer plug member 16
is shown in detail in FIG. 3A. The barrel portion 4 terminates in a
curved radially inwardly directed circumferential flange 30 which
is received within outwardly open annular recess 24. Overlying
recess defining surface 26 is in overlying surface to surface
contact with flange 30. This joint provides a mechanical interlock
which resists relative axial separation of the plug 10 and the bat.
In the form of joint shown in FIG. 3B curved flange 30' has its
undersurface in surface to surface contact with lower annular
surface 28' and has its free end in engagement with upper annular
surface 26'. This is a preferred form of joint which provides the
desired mechanical interlock and joint stability.
Referring once again to FIGS. 2 and 3, it is seen that the inner
plug member 18 has a tubular inner core 32 which has a closed upper
end 34. A generally cylindrical body portion 36 is spaced radially
outwardly from inner core 32 and is preferably coaxial therewith.
Connecting means 38 secure the cylindrical body portion 36 to the
tubular inner core 32. The inner plug member 18 has a generally
radially outwardly directed stabilizer portion 42 which, in the
form shown, extends from cylindrical body portion 36 radially
outwardly and angularly upwardly. Stabilizer portion 42 preferably
emerges from cylindrical body portion 36 at a position spaced
upwardly from the bottom thereof and extends circumferentially
around body portion 36. Stabilizer portion 42 terminates at or
closely adjacent the periphery of outer plug member 16 preferably
at a position within the cylindrical lower portion 20. While it is
preferred that the outwardly directed stabilizer portion 42
terminate at or closely adjacent the surface of outer plug member
16, if desired it may terminate at or closely adjacent the lower
annular surface 28. It, however, should not emerge at any higher
level of the outer plug member 16.
Contact between the outer extremity 44 of outwardly directed
stabilizer portion 42 and the inner surface 46 of barrel 4
establishes frictional engagement which resists undesired relative
movement between end plug 10 and barrel 4. The maximum diameter of
inner plug member 18 is preferably greater than the diameter of the
bat end opening defined by flange 30. As has been stated above,
while the stabilizer portion 42 preferably extends to the surface
of outer plug member 16, if desired it may be terminated at a
position radially inwardly of the surface of outer plug member 16,
but closely adjacent thereto. While close adjacency does not
provide direct frictional engagement between outer extremity 34 and
inner surface 36, the quantity of outer plug member 16 material
interposed is sufficiently small that the rigidifying effect of the
stabilizer portion 42 is obtained and frictional resistance to
movement is effected.
The circumference of lower portion 20 of outer plug member 16 is
preferably in surface to surface contact with bat inner surface 46.
This not only increases the frictional engagement but also serves
to effect a seal of the bat end to resist entry of moisture and
foreign matter into the bat interior.
As is seen in FIG. 2, in the form of plug shown in this form of the
invention the outwardly directed stabilizer portion 42 is
circumferentially discontinuous to provide a plurality of outwardly
directed stabilizer segments 42'. It is preferable in the interest
of uniform plug securance to provide a minimum of four
symmetrically positioned stabilizer segments 42'. Also, this
segmented approach results in an economic advantage as it reduces
the amount of material employed in the inner plug member 18.
Alternatively, the stabilizer portion 42 may be circumferentially
substantially continuous, if increased restraint against undesired
plug movement is desired. For example, the stabilizer portion may
have a generally continuous ring shape configuration with a
circular continuous outer circumference, bu openings between the
outer circumference and cylindrical body 36 may be provided, or, if
desired, it may have no openings.
The outer extremity 44 of stabilizer portion 42 preferably has a
substantially uniform thickness. The extremity 44 has a radius of
curvature which approximates either that of lower portion 20 or the
lower annular surface 28 of outer plug member 16 depending upon
which surface the extremity is adjacent.
It will, therefore, be appreciated that the end plug 10 provides
desired sound and vibration dampening characteristics through the
compressively resilient outer plug member 16 and the effectiveness
of the joint between the plug 10 and the ball bat is mechanically
insured. Not only is the cooperative interengagement between flange
30 and annular recess 24 effective in preventing separation of the
plug from the bat body, but the likelihood of severe mechanical
shock, frequently encountered in ball bat usage, compressing the
outer plug member 16 with resultant undesired movement of the plug
10 with repect to the bat body is eliminated. The rigidifying
structural supporting influence of inner plug member 18 coupled
with the increased frictional engagement effected adjacent outer
extremity 44 of stabilizer portion 42 serves to effectively resist
relative axial displacement of the plug 10 either inwardly or
outwardly with respect to the bat body.
The composite plug of this invention is adapted to be economically
manufactured. In one preferred form, the inner plug member 18 is
first molded to the desired configuration. After this has been
accomplished, the outer plug member may be molded around the inner
plug member 18 employing the latter as a portion of the mold core.
In this connection it will be noted that as is shown in FIG. 3 the
lower extremity 48 of tubular inner core 32 extends farther
downwardly than the lower surface 50 of outer plug member 16. This
serves to provide a lower tubular region of inner core 30 with
which the mold portion may be engaged during formation of outer
plug member 16. It will also be noted that the thickness of upper
portion 22 of outer plug member 16 as well as the depth of annular
recess 24 may be controlled by adjusting the dimensions of the
inner plug member 18 and mold accordingly. This plug design and
method also permit selection of an aesthetically pleasing material
color for the outer plug member 16 to permit upper portion 22 to be
attractively matched with the exposed decorative and/or protective
bat finish.
Another preferred form of inner plug member is shown in FIGS. 4
through 6. In this form of inner plug member, a tubular core
element 54 has an upper closed end 56 which is upwardly domed and
terminates in a peak 58. The outer cylindrical body portion 60 is
rigidly connected to the tubular core 52 by vertical, radially
extending wall sections 62. These wall sections, in the form
illustrated, originate within the lower half of tubular core
element 54 and extend upwardly to a position closely adjacent upper
closed end 56. As is shown in FIG. 4, this provides a series of
curved elongate passageways 66 between tubular core element 54 and
outer body portion 60 separted by wall sections 62.
This form of inner plug member also has a radially outwardly
directed stabilizer portion which is divided into stabilizer
segments 68. Stabilizer segments 68 are connected to the outer
surface 70 of cylindrical body portion 60. These segments 68, in
the form shown, increase in width as they extend outwardly from the
body portion 60. The segments 68 extend radially outwardly and
angularly upwardly. While it is preferred to provide an upward
angular orientation to segments 68, they may be disposed
substantially horizontally is desired. The segments 68 are all
preferably of substantially the same size. As is shown in FIGS. 5
and 6, reinforcing walls 72 extend radially outwardly from the
outer surface 70 of cylindrical body portion 60 and are in
underlying supporting contact with segments 68. As is shown in the
bottom plan view of FIG. 6, the reinforcing walls have free ends
terminating in an enlarged circular column 74 which has a diameter
slightly greater than the thickness of the remaining portion of the
supporting wall 72. Reinforcing walls 72 terminate at a position
spaced radially inwardly from the outer extremity 76 of segments
68.
In effecting the manufacture of an end plug employing the type of
inner plug member shown in FIG. 4 through 6, the same procedure as
has been described in respect to the composite plug shown in FIGS.
2 and 3 may be employed. The resultant composite plug will have a
reinforcing inner plug member which serves in essentially the same
capacity as that described in connection with FIGS. 2 and 3.
It is noted that, as is shown in FIG. 3A, the outer periphery 80,
which is that section of the upper portion 22 of the end plug in
overlying surface to surface contact with flange 30, preferably has
a thickness greater than the flange 30 of the barrel 4. This
portion serves to provide added resistance to undesired axial
movement of the end plug farther into the barrel 4. Such movement
could readily occur through physical impact applied axially
directly to the end plug 10. Where a resiliently compressive
material which possesses a substantial degree of rigidity is
employed in outer plug member 16, portion 80 may be provided in the
form of a relatively thin overlying lip which will serve the same
purpose of resisting inward displacement of the plug. It may be
desired in some instances to have the flange substantially
completely covered by outer peripheral portion 80 for both
aesthetic reasons as well as mechanical reasons. It will be
appreciated that outwardly directed stabilizer portion 42 also
provides frictional resistance to such movement.
FIG. 7 illustrates an inner plug member 88, generally similar to
that shown in FIG. 4, except that the stabilizer portion 90 is
circumferentially substantially continuous in order to provide
increased restraint against undesired plug movement within the bat.
In the form shown, the stabilizer 90 has a generally continuous
ring-shaped configuration with a circular continuous outer
circumference 92. The inner plug member 88 may, if desired, have a
configuration generally identical as that illustrated in FIGS. 4
through 6, except for the presence of modified stabilizer 90. In
the form illustrated like reference numerals have been employed to
reflect the presence of these similarities.
The embodiment shown in FIG. 8 may be essentially identical to that
shown in FIG. 7, except for the presence of a modified stabilizer
portion 94 which has a generally continuous ring-shaped
configuration provided with a circular continuous outer
circumference 96 and a plurality of openings 98 disposed between
the outer circumference 96 and the outer circumference 70 of the
cylindrical body portion 60.
The hollow bat of this invention may be made of any suitable
tubular material which possesses sufficient strength to function
effectively under the mechanical loads which will be encountered in
normal use. The material must also provide durability to avoid
potentially deleterious effects of exposure to environmental
conditions, such as weather and soil variations. In addition, it
should be capable of withstanding the mechanical abuse to which
such products are frequently subjected. It is preferred that the
bat be manufactured from metal, such as aluminum or steel
(including alloys thereof) which may be decoratively and/or
protectively finished, if desired. A particularly effective series
of appropriate aluminum alloys are the aluminum-zinc alloys such as
the alloys designated 7075 and 7005, with a T6 or T53 temper being
preferred.
It will, therefore, be appreciated that the end plug and bat
structure of this invention provide a hollow bat which is adapted
to receive one or two composite plugs of this invention in
effective mechanical joinder which may be economically provided
without the need for use of metal to metal joining techniques, such
as welding. Also, the need for separate adhesives is eliminated.
The composite plug has a substantially rigid inner reinforcing
member which is adapted to provide improved frictional engagement
between the surface of the bat body and the plug member to resist
undesired relative axial movement between the two. The outer plug
member is composed of a compressively resilient material which is
adapted to dampen noise and vibrations. An outwardly open annular
recess is provided in the outer plug member and a radially inwardly
directed flange is formed in the hollow ball end. The flange
portions extend into the annular recess to provide an effective
mechanical interlocking joint which resists relative axial movement
between the end plug and the bat portion. The inner plug member is
uniquely configurated to facilitate molding the same as a unitary
part and subsequently molding the outer plug member as a unitary
part therearound. The plug structure of this invention may be
employed in the barrel end of the bat and, if desired, may be
provided with a modified knob configuration or other suitable
configuration and be provided in the handle portion of the bat with
the plug structure and joint structure otherwise being
identical.
For purposes of illustration, a bat of the "bottle" variety having
cylindrical barrel and handle portions separated by a tapered
portion has been shown. It will be appreciated that other forms of
hollow bat configurations may effectively be employed with the plug
of this invention. The term "generally cylindrical" as used herein
to refer to barrel or handle portions of bats shall include hollow
bat portions provided with a taper such as might be found in bats
which are continuously or partially tapered within these
portions.
Whereas particular embodiments of the invention have been described
above for purposes of illustraton, it will be evident to those
skilled in the art that numerous variations of the details may be
made without departing from the invention as defined in the
appended claims.
I claim:
* * * * *