U.S. patent application number 13/285977 was filed with the patent office on 2012-11-01 for customized racquet stringing system.
This patent application is currently assigned to WILSON SPORTING GOODS CO.. Invention is credited to Robert T. Kapheim, John B. Lyons, Ronald R. Rocchi, William D. Severa.
Application Number | 20120277039 13/285977 |
Document ID | / |
Family ID | 45421746 |
Filed Date | 2012-11-01 |
United States Patent
Application |
20120277039 |
Kind Code |
A1 |
Severa; William D. ; et
al. |
November 1, 2012 |
CUSTOMIZED RACQUET STRINGING SYSTEM
Abstract
A racquet stringing system for use with a stringing machine
configured for stringing a racquet having a string bed of racquet
string formed of a plurality of main string segments and a
plurality of cross string segments. The stringing system includes a
control unit and at least one racquet string algorithm operably
coupled to the control unit. The control unit is coupled to the
racquet stringing machine and includes a processing unit. The
racquet stringing algorithm is configured to enable the control
unit to produce at least three different string tension signals for
tensioning the main string segments and/or cross string segments of
the racquet on the stringing machine based upon one or more racquet
head profiles and/or one or more player characteristics.
Inventors: |
Severa; William D.; (Darien,
IL) ; Rocchi; Ronald R.; (Naperville, IL) ;
Lyons; John B.; (Wilmette, IL) ; Kapheim; Robert
T.; (Elmhurst, IL) |
Assignee: |
WILSON SPORTING GOODS CO.
Chicago
IL
|
Family ID: |
45421746 |
Appl. No.: |
13/285977 |
Filed: |
October 31, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12946215 |
Nov 15, 2010 |
8066593 |
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13285977 |
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12077010 |
Mar 14, 2008 |
7833118 |
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12946215 |
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60922938 |
Apr 11, 2007 |
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Current U.S.
Class: |
473/557 |
Current CPC
Class: |
A63B 60/42 20151001;
A63B 51/14 20130101; A63B 2225/50 20130101; A63B 51/004
20200801 |
Class at
Publication: |
473/557 |
International
Class: |
A63B 51/14 20060101
A63B051/14 |
Claims
1. A racquet stringing system for use with a stringing machine
configured for stringing a racquet having a string bed of racquet
string formed of a plurality of main string segments and a
plurality of cross string segments, the stringing system
comprising: a control unit coupled to the racquet stringing
machine, the control unit including a processing unit; and at least
one racquet string algorithm operably coupled to the control unit,
the racquet stringing algorithm configured to enable the control
unit to produce at least three different string tension signals for
tensioning the main string segments and/or cross string segments of
the racquet on the stringing machine based upon one or more racquet
head profiles and/or one or more player characteristics.
2. The racquet stringing system of claim 1 wherein the control unit
is mounted to the stringing machine.
3. The racquet stringing system of claim 1, wherein the control
unit is removably mounted to the stringing machine.
4. The racquet stringing system of claim 1, wherein the stinging
machine includes a string tensioning assembly that receives the
string tension signals.
5. The racquet stringing system of claim 4, wherein the string
tensioning assembly includes a string puller head for receiving the
racquet string and for releasably clamping the string and a puller
motor coupled to the string puller head for applying tension to the
string clamped by the puller head.
6. The racquet stringing system of claim 5, wherein the puller
motor moves the string puller head away from a head portion of the
racquet to produce tension on one of the main string segments or
one of the cross string segments being strung, and wherein the
tension produced by the puller motor corresponds to one of the
string tension signals.
7. The racquet stringing system of claim 1, wherein each of the
racquet head profiles includes one or more racquet characteristics
selected from the group consisting of the number of main string
segments the racquet head is configured to support, the position of
each main string segment relative to the other main string segments
or to the racquet, the position of each cross string segment
relative to the other cross string segments or to the racquet, the
number of cross string segments the racquet head is configured to
support, the head size of the head portion, the geometry of the
head portion of the racquet, the moment of inertia of the racquet,
the balance point of the racquet, the recommended string tension
for the racquet by the racquet supplier, the maximum recommended
string tension for the racquet by the racquet supplier, and
combinations thereof.
8. The racquet stringing system of claim 1, wherein each of the
racquet head profiles includes information selected from the group
consisting of a racquet model name, a racquet supplier name, a
model year associated with the racquet, and combinations
thereof.
9. The racquet stringing system of claim 1, wherein the at least
three different string tension signals control unit include a
specific string tension signal for each of the main string segments
and/or each of the cross string segments.
10. The racquet stringing system of claim 1, wherein the one or
more player characteristics are selected from the group consisting
of player's skill level, player's tension preferences, desired
feel, desired power, desired control, and combinations thereof.
11. The racquet stringing system of claim 1, wherein the string
tension signals provided by the control unit for the main string
segments correspond to at least two different string tension
values.
12. The racquet stringing system of claim 11, wherein the string
tension signals provided by the control unit for the main string
segments correspond to at least three different string tension
values.
13. The racquet stringing system of claim 1, wherein the string
tension signals provided by the control unit for the cross string
segments correspond to at least two different string tension
values.
14. The racquet stringing system of claim 13, wherein the string
tension signals provided by the control unit for the cross string
segments correspond to at least three different string tension
values.
15. The racquet stringing system of claim 1 wherein the control
unit includes at least one communication port.
16. The racquet stringing system of claim 15 wherein the
communication port is selected from the group consisting of a
universal serial bus interface, a SD card interface, a wireless
USB, a wireless receiver, a cellular phone interface, CD reader, a
DVD reader and combinations thereof.
17. The racquet stringing system of claim 15, further comprising an
electronic storage device remote from the control unit, and wherein
the electronic storage device includes content selected from group
consisting of the string tension program, at least one racquet head
profile, at least one user profile and combinations thereof.
18. The racquet stringing system of claim 17, wherein the
electronic storage device is a telecommunications device, a
cellular phone, a personal data assistant, a computer, a flash
drive, a CD, a DVD and combinations thereof.
19. The racquet stringing system of claim 17, wherein the
electronic storage device communicates with the communication port
through a direct connection, a wireless transmitter or a wired
connection.
20. The racquet stringing system of claim 1, wherein the stringing
platform further includes a plurality of frame clamps for securing
a head portion of the racquet to the stringing platform.
21. The racquet stringing system of claim 1, wherein the control
unit includes a memory operably coupled to the processing unit.
22. The racquet stringing system of claim 21, wherein the memory
holds information selected from the group consisting of one or more
racquet head profiles, player characteristics, racquet stringing
machine user profiles, racquet stringing algorithms, software
capable of tracking operation and/or usage history of the stringing
machine, and combinations thereof.
23. The racquet stringing system of claim 1, wherein the control
unit is portable and configured to be moved from one racquet
stringing machine to another.
Description
RELATED U.S. APPLICATION DATA
[0001] The present application is a continuation of U.S. patent
application Ser. No. 12/946,215 entitled "Customized Racquet
Stringing System and Method", which is a continuation-in-part
application of U.S. patent application Ser. No. 12/077,010, filed
on Mar. 14, 2008, now U.S. Pat. No. 7,833,118, which claims
priority under 35 U.S.C. .sctn.119(e) to U.S. Provisional
Application Ser. No. 60/922,938 filed on Apr. 11, 2007.
FIELD OF THE INVENTION
[0002] The present invention relates to a machine for stringing
racquets and a system for providing customized racquet stringing of
racquets. This stringing machine has enhanced ergonomic features to
accommodate individuals of various sizes and their personal
preferences.
BACKGROUND OF THE INVENTION
[0003] The act of stringing a racquet requires a considerable
amount of manual labor. Stringing machines assist in the process by
maintaining the racquet in place and providing desired tension in
the strings, but a majority of the work involved is performed by a
person. More particularly, a person must align the racquet within
the stringing machine, and then string each of the cross or main
strings individually, followed by weaving each of the cross and
main strings to form the resulting string grid.
[0004] Those in the racquet stringing business often spend many
hours a day standing in front of a stringing machine. Conventional
stringing machines include a stringing platform with a turntable
positioned on top of a fixed stand. The turntable spins within a
plane parallel to the floor. Because of the fixed orientation of
the stand and the planar position of the turntable, the person
stringing the racquet must adjust his or her posture to conform to
the position of the stringing machine. Furthermore, the various
steps involved in stringing a racquet require the racquet stringer
to assume a variety of stances. In particular, one of the racquet
stringer's shoulders is often positioned much higher than the
other. Also, the fixed orientation of the stringing machine often
induces the racquet stringer to hunch over the turntable. The
awkward posture induced by conventional stringing machines often
causes injuries and fatigue, which ultimately lead to reduced
efficiency in the performance of the racquet stringer.
[0005] It would thus be desirable to provide a stringing machine
that is ergonomically designed to allow users to work with the
stringing machine without having to assume awkward or uncomfortable
positions. In doing so, it would also be desirable to provide an
ergonomically-designed stringing machine that can automatically
adjust its orientation to accommodate individuals of various sizes.
It would be further desirable for such an ergonomically-designed
stringing machine to be adjustable to accommodate personal
preferences.
[0006] Racquets are typically strung with a single string tension
value for the entire string bed that typically matches the
manufacturer's recommended string tension for the racquet. In some
instances, racquets may be strung with two tension values, one
tension value may be used for stringing the main string segments
and a second string tension value may be used for the cross string
segments of the racquet string. In other instances, if a player
desires a stiffer or softer string bed, the racquet will typically
be strung at the single tension value that is either slightly
higher or slightly lower than the recommended string tension of the
racquet, or at the higher or lower end of the recommended string
tension range for a racquet. This approach is generally applied to
all racquets including those of different head shapes and for
players having different skills.
[0007] It would thus be desirable to provide a system and method of
stringing a racquet that provides additional flexibility and
adaptability to the better match a particular racquet design or
player. It would also be desirable to have a racquet stringing
machine that could facilitate the customized stringing of a
racquet.
SUMMARY OF THE INVENTION
[0008] The present invention presents an ergonomically-designed
racquet stringing machine for stringing of a racquet by a user. The
racquet stringing machine can be adjusted to accommodate
individuals of various sizes and their personal preferences. The
stringing machine includes a base configured to support the
stringing machine on a generally horizontal surface, a stand
extending upwardly from the base, and a stringing platform coupled
to an upper region of the stand, with the stringing platform
supporting at least one racquet mount for securing the racquet
about a stringing plane. The stringing machine may also include an
electronic control unit.
[0009] In one embodiment, the stringing machine includes a platform
tilt assembly coupled to the stringing platform and to the stand,
with a control unit coupled to the stringing platform and operably
coupled to the platform tilt assembly. In this embodiment, the
control unit is capable of generating a first control signal to the
platform tilt assembly to adjust the position of the stringing
platform and the angle of the stringing plane with respect to the
horizontal surface, thereby enabling a user to tilt the stringing
platform forward for a more comfortable position during one or more
steps of the racquet stringing process. For example, the platform
tilt assembly may be configured to adjust the angle of the
stringing plane with respect to the horizontal surface by an amount
within the range of 0 to 30 degrees, or within the range of 1 to 15
degrees. More particularly, the stringing platform includes a front
surface generally facing the user during stringing of the racquet.
The platform tilt assembly can adjust the angle of the stringing
plane about a generally horizontal pivot axis extending generally
parallel to the front surface of the stringing platform.
[0010] The platform tilt assembly can include a drive unit
configured to reposition an actuator in response to the first
control signal from the control unit. In particular, the actuator
can be coupled between the stringing platform and the stand, with
the actuator extending to rotate the stringing platform about a
generally horizontal pivot axis with respect to the stand.
[0011] The stringing platform may support a turntable and a string
tensioning assembly, with the string tensioning assembly including
a string puller head coupled to a puller motor. The turntable and
the string puller head can maintain their positions relative to the
stringing plane as the stringing platform is tilted by the platform
tilt assembly. In certain embodiments, the string puller head may
include a self-guiding tension puller having a tapered housing.
[0012] Similarly, the stringing machine may include a control
assembly housing coupled to the stringing platform with the control
assembly housing being capable of tilting along with the stringing
platform. The control assembly housing may be formed primarily of
die-cast aluminum. Additionally, the control assembly housing may
define a tool storage region that is shaped to retain tools in all
stringing plane positions of the stringing machine.
[0013] In certain embodiments, the stringing machine may possess a
tilted configuration of the stringing platform in which the
stringing plane is fixed at an angle of about 1 to about 15 degrees
from the horizontal surface. Alternatively, the angle of the
stringing plane may be adjusted by manually adjusting a platform
tilt assembly coupled to the stringing platform, at an angle of 1
to about 15 degrees from the horizontal surface, for example.
[0014] As mentioned above, the stringing machine may include a tool
storage region coupled to the stringing platform and designed to
hold tools. The tool storage region or tool storage tray may have a
bottom surface lying in a plane that is non-parallel with the
stringing plane. For example, the bottom surface of the tool
storage tray my lie in a plane that is approximately parallel with
the horizontal surface while the stringing plane is tilted. As a
further example, the bottom surface of the tool storage tray be lie
in a plane that is at an angle of about 1 to about 15 degrees from
the stringing plane.
[0015] The stringing machine may also include at least one string
clamps that can be positioned and repositioned within the stringing
plane, with each string clamp having an over-molded grip. The
over-molded grip may be formed substantially of rubber. This grip
provides improved comfort to the user.
[0016] The stringing platform may include a turntable rotatable
about a generally vertical axis. Additionally, the turntable may
include a ring centered about the generally vertical axis, with a
releasable resistance assembly configured to releasably engage the
ring to prevent rotation of the turntable about the generally
vertical axis.
[0017] In another embodiment, the stringing machine includes a
height adjustment assembly coupled to the stand, the stringing
platform, and/or the base, and a control unit operably coupled to
the height adjustment assembly. In this embodiment, the control
unit is capable of generating a first control signal to the height
adjustment assembly to automatically adjust the height of the
stringing machine based upon a selected user profile. The height
adjustment assembly can adjust the height of the stringing machine
in response to the first control signal by a distance within the
range of 0.25 inches to 24 inches, for example. More preferably,
the height adjustment range can be approximately 11 inches. The
height adjustment assembly may include a height adjustment motor
coupled to the stand, with the height adjustment motor driving a
gear assembly to adjust the height of the stringing machine. The
control unit may be capable of storing at least one user profile
and automatically adjusting the height of the stringing machine in
accordance with the selected stored profile.
[0018] In certain embodiments, the stringing machine may include an
electronic control unit operably coupled to the stringing platform,
wherein the control unit is capable of storing at least one user
profile and generating a first control signal to automatically
adjust at least one parameter of the machine, such as machine
height, angle of stringing platform, or string tension, based upon
a selected user profile. In particular, the user profile may
include the user's height, a preference for metric or English
units, a language preference (English, Spanish, French, German,
etc.), tension indication preference (visual, auditory, or both),
stringing pattern preference, pre-stretch preference, and/or any
other specified preferences. For example, the electronic control
unit may adjust the height of the stand based on the user's
height.
[0019] Other features that the electronic control unit may possess
include preferential tension control, such as the capability to
adjust the tension in the strings of a racquet while the racquet is
being strung in accordance with the user's preference, and/or the
capability to maintain tension in cross strings at a different
level of tension than in main strings. Further, the control unit
can be used to provide a unique combination of tension values to
the array of cross and main string segments comprising the string
bed of the racquet. The electronic control unit may include a
display having a touch pad on which a user can adjust tension in
the string during one or more steps of the stringing process.
Additionally, or alternatively, the electronic control unit may be
configured to allow for the automatic machine adjustments to be
manually overridden. The electronic control unit may also have the
capability to display two or more tension notification signals,
such as a visual blinking of lights and an auditory beeping
indicator. The user may elect a single tension notification signal
of their choice, or any two or more of the signals to be used
simultaneously.
[0020] Also the electronic control unit may include a USB
interface, an SD card interface, an MP3 player interface, one or
more speakers, and/or other peripheral capabilities that allow a
user to simultaneously employ other electronic devices for
listening to music, communicating with others, or the like. The
control unit itself may be modular, thereby allowing a user to
replace or repair just the control unit, rather than having to
either replace the entire machine or send the entire machine to a
repair facility. Additionally, the stringing machine may include an
external power source operatively attached to the electronic
control unit. By locating the power source outside the body of the
stringing machine, this configuration may facilitate importation
procedures concerning approval of electrical devices.
[0021] The invention also presents a method of controlling tension
in a racquet while stringing a racquet using a racquet stringing
machine as described herein. More particularly, the method includes
securing a racquet to the stringing platform of a racquet stringing
machine and selecting a stored user profile in an electronic
control unit operably coupled to the stringing platform, in
response to which the electronic control unit generates a first
signal to automatically adjust tension in the string. The user
strings main strings in the racquet, guides the string through a
tension puller, strings cross strings in the racquet, and again
guides the string through the tension puller. The electronic
control unit may pre-stretch the string, depending on the user's
preferences. As described above, the user may adjust tension in the
string by pressing an adjustment indicator on a display operably
connected to the electronic control unit.
[0022] According to another preferred aspect of the invention, a
customized racquet stringing system is provided for a racquet
having a string bed of racquet string formed of a plurality of main
string segments and a plurality of cross string segments. The
stringing system includes a racquet stringing machine and a control
unit. The racquet stringing machine includes a base and a stringing
platform. The base is configured to support the stringing machine
on a support surface. The stringing platform is coupled to the
base. The stringing platform includes a turntable for rotatably
mounting the racquet and a string tensioning assembly. The string
tensioning assembly is configured to receive one or more string
tension control signals. The control unit is operably coupled to
the string tensioning assembly. The control unit includes a
processing unit and a memory. The control unit is configured to
execute a string tensioning program and to provide a plurality of
the string tension control signals based off of the string
tensioning program to the string tensioning assembly. The plurality
of string tension control signals correspond to at least three
separate string tension values applied to the plurality of main
string segments and/or the plurality of cross string segments
during the stringing of the racquet.
[0023] Any one or more of the stringing machine embodiments and
methods described herein may be applied to machines for stringing
tennis racquets, racquetball racquets, squash racquets, badminton
racquets, and any other strung racquet. Regardless of the type of
racquet, compatibility of the stringing machine with the user is
greatly improved by using any of the stringing machine enhancements
in this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a perspective view of a racquet stringing
machine.
[0025] FIGS. 2A and 2B are side views of a racquet stringing
machine showing how the angle of the stringing platform can be
adjusted.
[0026] FIG. 3 is a side view of a user in an induced posture while
clamping a racquet on a racquet stringing machine.
[0027] FIG. 4 is a side view of a user in a preferred posture while
clamping a racquet on a racquet stringing machine.
[0028] FIG. 5 is a side view of a user in an induced posture while
stringing main strings on a racquet.
[0029] FIG. 6 is a side view of a user in a preferred posture while
stringing main strings on a racquet.
[0030] FIG. 7 is a side view of a user in an induced posture while
weaving cross strings on a racquet.
[0031] FIG. 8 is a side view of a user in a preferred posture while
weaving cross strings on a racquet.
[0032] FIG. 9 is a top view of a racquet stringing machine.
[0033] FIG. 10 is a perspective view of a stringing platform.
[0034] FIG. 11A is a partial view of the string puller head on the
stringing platform of FIG. 10.
[0035] FIG. 11B is a cross-sectional view of the string puller head
of FIG. 11A, taken along line 11-11.
[0036] FIG. 12A is an interior view of a stringing platform as
viewed from the top.
[0037] FIG. 12B is an interior view of a stringing platform as
viewed from the rear.
[0038] FIG. 12C is an interior view of a stand at its connection to
a stringing platform.
[0039] FIG. 13 is a cross-sectional view of the stringing platform
of FIG. 10, taken along line 13-13.
[0040] FIG. 14 is a perspective view of string clamp having an
over-molded grip.
[0041] FIG. 15 is a block diagram of screen displays associated
with the control unit.
[0042] FIGS. 16-20 are individual screen displays each associated
with the control unit.
[0043] FIG. 21 is a block diagram of control unit features.
[0044] FIG. 22 is a perspective view of a racquet stringing machine
showing the fungibility of a modular electronic control unit.
[0045] FIG. 23 is a front view of a racquet including a string
bed.
[0046] FIG. 24 is a side view of the racquet of FIG. 23.
[0047] FIG. 25 is a front view of a different racquet also having a
string bed.
[0048] FIG. 26 is a block diagram of the control system and a
communication port, and the sensors and remote communication and
data devices that can interact with the control system.
[0049] FIGS. 26 through 28 provide side views of a head portion of
a racquet and the routing of racquet string during the stringing of
a racquet.
DETAILED DESCRIPTION OF THE INVENTION
[0050] Referring to FIG. 1, an ergonomically-designed racquet
stringing machine is indicated generally at 20. The ergonomic
features of the stringing machine 20 are intended to provide
enhanced comfort for a user during the process of stringing a
racquet 32. In particular, the stringing machine 20 may
automatically adjust its orientation to accommodate individuals of
various sizes. Additionally or alternatively, the stringing machine
20 may be adjustable to accommodate personal preferences.
[0051] Referring to FIGS. 23-25, the racquet 32 includes a racquet
frame 11 having a hoop-shaped head portion 12 and an elongated
handle 13. The handle 13 extends along the longitudinal axis or
centerline CL of the racquet 32. The head portion 12 supports a
string bed 15 that provides a hitting surface for a tennis ball. In
one preferred embodiment, the head portion 12 can have a generally
oval hoop or head. In another preferred embodiment, such as the
racquet 32 of FIG. 25, the shape of the hoop defined by the head
portion 12 of the racquet is ovoid or ovate shaped and is
relatively wide and blunt at the top and relatively narrow and
tapered at the bottom. In other preferred embodiments, the head
portion of the racquet can have other shapes. Referring to FIG. 23,
the string bed 15 includes a plurality of generally parallel main
strings segments 16, which extend generally parallel to the
longitudinal axis CL of the racquet 32, and a plurality of
generally parallel cross strings segments 17, which extend
generally perpendicularly to the axis CL. The present invention is
applicable to other racquets having other orientations, and
numbers, of main and cross string segments. The racquet frame is
provided with a plurality of string holes 19 though which racquet
string is threaded when the racquet is being strung. The string
holes 19 are orientated about the head portion 12 for receiving the
racquet string forming the main string segments 16 and the cross
string segments 17.
[0052] Referring to FIG. 1, the stringing machine 20 includes a
base 22 configured to support the stringing machine 20 on a
generally horizontal surface or other support surface, a stand 24
extending upwardly from the base 22, and a stringing platform 26
coupled to an upper region 28 of the stand 24, with the stringing
platform 26 supporting at least one racquet mount 70 for securing
the racquet 32 about a stringing plane 40. The base 22 and stand 24
may be a single-leg design, as illustrated in FIGS. 1, 2A, and 2B.
Alternatively, a two, three, or four-leg design (not shown) may
work equally well. In an alternative preferred embodiment, the
stringing machine may be formed without a stand. In this
embodiment, the stringing machine can be placed onto a table or
other elevated structure. The stringing machine 20 may also include
an electronic control unit 30.
[0053] Conventional stringing machines 46 (FIGS. 3, 5, and 7)
include a stand extending perpendicularly from a base at a fixed
height with a stringing platform affixed to the top of the stand,
such that the stringing platform remains in a plane essentially
parallel to the ground. Although this fixed configuration of the
stringing machine may be comfortable for a small percentage of
users, the adjustable stringing machine 20 disclosed in this
invention provides a comfortable working position to a much wider
range of users. For example, in certain embodiments, as illustrated
in FIGS. 2A and 2B, the stringing platform 26 can be tilted from 0
to about 30 degrees, or from 1 to about 15 degrees from horizontal
from a mounted position atop the stand 24, thereby creating a more
comfortable position for a user during various steps of the
stringing process. As another example, in certain embodiments, the
height of the stand 24 can be raised or lowered by a distance
within the range of 0.25 inches to 24 inches, for example, thereby
equally accommodating both short users and tall users. In one
particularly preferred embodiment the range of height adjustment of
the stand is approximately 11 inches, wherein the height of the
stringing machine, measured from horizontal to a horizontally
positioned string bed (or stringing plane), can range from
approximately 40 inches to approximately 51 inches. Other stringing
machine height ranges can also be used. These adjustment features
are described in greater detail below.
[0054] When stringing a racquet 32, the racquet 32 must first be
clamped onto the adjustable stringing platform 26. As illustrated
in FIG. 3, conventional stringing machines 46 induce poor posture
for many users trying to clamp the racquet onto the stringing
platform. By adjusting the height of the stand 24, the height of
the stringing platform 26 may be raised or lowered to accommodate
the user, thereby preventing the user from hunching over the
stringing platform 26, as shown in FIG. 4. Any suitable
height-adjusting mechanism can be applied to the stringing machine
20, such as a telescoping height-adjustment mechanism. A more
detailed description of height-adjusting mechanisms is provided
below.
[0055] Additional steps in the stringing process also induce poor
posture for many users. As shown in FIG. 5, the process of
stringing the main strings may cause neck strain or other
discomfort due to the positioning of the stringing platform with
respect to the user's position. By adjusting the height of the
stand 24 as well as the angle of the stringing platform 26, the
position of the stringing platform 26 may be adjusted to
accommodate the user, thereby allowing the user to stand upright in
a relatively comfortable position, as shown in FIG. 6.
[0056] Similarly, the detail-oriented process of weaving cross
strings may also cause neck strain or other discomfort, as
exemplified in FIG. 7. By further adjusting the height of the stand
24 and the angle of the stringing platform 26, the height and angle
of the stringing platform 26 can be arranged in a position that
allows the user to weave the cross strings in a more ergonomically
preferable position, as shown in FIG. 8.
[0057] FIG. 2A shows a side view of a stringing machine 20 with the
stringing platform 26 in a horizontal position, such that the
stringing plane 40 is parallel to the floor, and FIG. 2B shows the
same stringing machine 20 with the stringing platform 26 in a
tilted position in which the stringing plane 40 is tilted at an
angle .theta. with respect to the horizontal position. The tilting
of the stringing platform 26 may be performed by any suitable drive
mechanism known to those skilled in the art, as there are many
suitable drive mechanisms that would be appropriate for raising and
lowering the angle of the stringing platform 26. As explained in
greater detail below, an electronic control unit 30 may be used to
electronically control the angle .theta. of the stringing platform
26. However, in certain embodiments, the stringing machine 20 may
possess a tilted configuration of the stringing platform 26 in
which the stringing plane 40 is fixed at an angle of about 1 to
about 15 degrees from the horizontal surface. Alternatively, the
angle .theta. of the stringing plane 40 may be adjusted by manually
adjusting a platform tilt assembly coupled to the stringing
platform 26, at an angle of 1 to about 15 degrees from the
horizontal surface, for example.
[0058] In one embodiment, the stringing machine 20 includes a
platform tilt assembly 48 coupled to the stringing platform 26 and
to the stand 24, with a control unit 30 (see FIGS. 1 and 9-13)
coupled to the stringing platform 26 and operably coupled to the
platform tilt assembly 48. In this embodiment, the control unit 30
is capable of generating a first control signal to the platform
tilt assembly 48 to adjust the position of the stringing platform
26 and the angle .theta. of the stringing plane 40 with respect to
the horizontal surface, thereby enabling a user to tilt the
stringing platform 26 forward, as illustrated in FIG. 2, for a more
comfortable position during one or more steps of the racquet
stringing process. For example, the platform tilt assembly 48 may
be configured to adjust the angle .theta. of the stringing plane 40
with respect to the horizontal surface by an amount within the
range of 0 to 30 degrees, or within the range of 1 to 15 degrees.
In other embodiments, other angular ranges can be employed. More
particularly, the stringing platform 26 includes a front surface 42
generally facing the user during stringing of the racquet 32. The
platform tilt assembly 48 can adjust the angle .theta. of the
stringing plane 40 about a generally horizontal pivot axis 44
extending generally parallel to the front surface 42 of the
stringing platform 26. The pivot axis 44, as represented in FIG. 2,
is perpendicular to the plane in which the drawing lies. The
stringing plane 40 is the plane in which a racquet 32 lies when the
racquet 32 is clamped to the stringing platform 26.
[0059] The platform tilt assembly 48 can include a drive unit 49
configured to reposition an actuator 50 in response to the first
control signal from the control unit 30, as illustrated in FIGS.
12A and 12B. In particular, the actuator 50 can be coupled between
the stringing platform 26 and the stand 24, with the actuator 50
extending outward from a lower region of a control assembly housing
64. When activated, the actuator 50 pushes against the stand 24,
thereby rotating the stringing platform 26 about the generally
horizontal pivot axis 44.
[0060] As illustrated in FIGS. 9-13, the stringing platform 26 may
support a turntable 54 and a string tensioning assembly 52, with
the string tensioning assembly 52 including a string puller head 56
coupled to a puller motor 58. The string tensioning assembly 52
pulls the strings to the desired tension during the stringing
process. The turntable 54 and the string puller head 56 can
maintain their positions relative to the stringing plane 40 as the
stringing platform 26 is tilted by the platform tilt assembly.
[0061] As illustrated in detail in FIG. 11A, the string puller head
56 may include a self-guiding tension puller 60. More particularly,
as depicted in FIG. 11B, the self-guiding tension puller 60 has a
tapered housing 62. Consequently, when a user is feeding the string
63 into the tension puller 60, little or no alignment is required
on behalf of the user, since the angle of the tapered housing 62
automatically guides the string 63 into the grip of the tension
puller 60, as indicated by the arrow in FIG. 11B.
[0062] The stringing machine 20 may also include a control assembly
housing 64 coupled to the stringing platform 26, with the control
assembly housing 64 being capable of tilting along with the
stringing platform 26. The control assembly housing 64 may be
formed primarily of die-cast aluminum. In fact, any or all of the
major components of the stringing machine 20, namely the base 22,
stand 24, and stringing platform 26, may be formed of die-cast
aluminum or other metal, wood, plastic, high-strength polymer,
composite materials, or any combination of these materials, for
example.
[0063] The control assembly housing 64 may define a tool storage
region 66, as shown in FIGS. 9 and 10, that is shaped to retain
tools in all stringing plane positions of the stringing machine 20.
The tool storage region or tool storage tray 66 may have a bottom
surface 68 lying in a plane that is non-parallel with the stringing
plane 40. For example, the bottom surface 68 of the tool storage
tray 66 may lie in a plane that is approximately parallel with the
horizontal surface while the stringing plane 40 is tilted. As a
further example, the bottom surface 68 of the tool storage tray 66
may lie in a plane that is at an angle of about 1 to about 15
degrees from the stringing plane 40. Alternatively, the tool
storage tray 66 can be configured in other recessed shapes for
retaining tools in all stringing plane positions. Additionally, the
control assembly housing 64 may also define an additional storage
region 69, shown in FIGS. 1 and 9, suitable for holding a PDA or an
MP3 player, for example.
[0064] As illustrated in FIGS. 1 and 9, the stringing platform 26
includes multiple frame clamps 70 for maintaining the frame of a
racquet 32 in place on the turntable 26, and at least one string
clamp 72 for maintaining the strings in place during the stringing
process.
[0065] Referring to FIGS. 1, 9 and 23, the frame clamps 70 engage
the head portion 12 of the racquet 32. The string clamps 72 can be
positioned and repositioned within the stringing plane 40. For
example, the string clamps 72 can be slid and rotated within curved
slotted tracks 74 illustrated in FIG. 9. The string clamps 72 may
be conventional string clamps; alternatively, the string clamps 72
may each have an over-molded grip 76 on a shaft of the string clamp
72, as illustrated in FIG. 14. The over-molded grip 76 is
preferably a replaceable slip-on, ergonomically-shaped adapter that
provides enhanced comfort to the user, and is suitably formed
substantially of rubber. The over-molded grip 76 may also be formed
of materials other than rubber, such as any suitable thermoplastic
polymer. The over-molded grip 76 featured on the string clamps 72
in FIG. 14 can be applied to string clamps having a lock lever as
well as string clamps having a squeeze-to-release pivot. FIG. 14
illustrates one preferred shape for the over-molded grip 76. In
alternative embodiments, other ergonomically desirable shapes can
be used. It is contemplated that the string clamp 72 is configured
to receive and function with a number of over-molded grips having
varying shapes, thereby allowing the string clamps to be customized
to a particular user or application. The over-molded grips 76 may
be interchangeable, meaning that a single string clamp 72 may
accept a variety of different grips, such that each user may place
their preferred grips 76 on the string clamps 72 during any given
stringing session.
[0066] Another feature that may be present on the stringing
platform 26 is a dark or black surface on a racquet-facing surface
78 of the stringing platform 26. The dark surface enables the user
to see the string more easily during the stringing process. A
racquet-facing surface 78 is indicated in FIG. 9 in a non-darkened
state for purposes of clarity.
[0067] The turntable 54 may be rotatable about a generally vertical
axis 80 (see FIG. 10). The axis 80 is positioned in a generally
vertical orientation when the stringing platform 26 is in an
un-tilted position, and the axis 80 tilts in conjunction with the
stringing platform 26, such that the axis 80 is generally
perpendicular with the stringing plane 40. The turntable 54 allows
the racquet 32 to spin in a plane parallel to a plane in which the
turntable 54 lies, thereby allowing a user to adjust the angle of
the racquet 32 as necessary, particularly when transitioning from
stringing the main strings to stringing the cross strings.
[0068] Additionally, the turntable 54 may include a ring 82
centered about the axis 80, with a releasable resistance assembly
84 configured to releasably engage, and disengage, the ring 82 to
prevent rotation of the turntable 54 about the axis 80, as
illustrated in FIG. 9. More particularly, the mechanism of the
releasable resistance assembly 84 may be similar to a bicycle
brake, with a lever operated by the user at one end and the
opposite end designed to contact the inner surface of the ring 82
when the brake is applied, thus creating sufficient friction to
prevent the turntable 54 from rotating. The releasable resistance
assembly 84 is configured to enable a user to quickly and easily
engage and lock the turntable 54, thereby preventing rotation of
the turntable, and enabling release of the turntable as needed
during use. This releasable resistance assembly 84 can bring the
turntable 54 to a stop in mid-rotation.
[0069] In another embodiment, illustrated in FIG. 12C, the
stringing machine 20 includes a height adjustment assembly 112
coupled to the stand 24, the stringing platform 26, and/or the base
22, and a control unit 30 operably coupled to the height adjustment
assembly 112. In this embodiment, the control unit 30 is capable of
generating a first control signal to the height adjustment assembly
112 to automatically adjust the height of the stringing machine 20
based upon a selected user profile. The height adjustment assembly
112 can adjust the height of the stringing machine 20 in response
to the first control signal by a distance within the range of 0.25
inches to 24 inches, for example. In certain embodiments, the
height of the stand 24 may be manually adjustable. Various heights
of the stringing machine 20 are illustrated in FIGS. 4, 6, and 8.
The height adjustment assembly 112 may include a height adjustment
motor 114 coupled to the stand 24, with the height adjustment motor
driving a gear assembly 116 to adjust the height of the stringing
machine 20, as illustrated in FIG. 12C. The gear assembly 116 may
include a threaded rod, as illustrated in FIG. 12C. Alternatively,
the gear assembly 116 may drive a chain that runs in a track within
the stand 24, or a screw drive may raise and lower the height of
the machine 20, for example. As with the drive mechanisms used to
tilt the stringing platform 26, those skilled in the art are
familiar with a variety of suitable drive mechanisms that would be
appropriate for raising and lowering the height of the stringing
machine 20. Therefore, the details of such mechanisms will not be
described in greater detail herein.
[0070] As mentioned, the stringing machine 20 may include an
electronic control unit 30 (FIG. 1) operably coupled to the
stringing platform 26, wherein the control unit 30 is capable of
storing one or more user profiles and generating a first control
signal to automatically adjust at least one parameter of the
machine 20, such as machine height, angle .theta. of stringing
platform 26, or string tension, based upon a selected user
profile.
[0071] In particular, the user profile may include the user's
height, a preference for metric or English units, a language
preference (English, Spanish, French, German, etc.), string tension
indication preferences (visual, auditory, or both) including main
string stringing tension, cross string pulling tension, knot
tension, and the rate at which the tension is applied to the
string, stringing pattern preference, pre-stretch preference,
and/or any other specified preferences. For example, the user may
input his or her height in response to which the electronic control
unit 30 may activate the drive mechanism to automatically adjust
the height of the stand 24 to achieve a preferred height of the
stringing platform 26 based on pre-programmed data correlating user
height with a comfortable turntable height. After clamping the
racquet 32 in place, the user may press a button on the electronic
control unit 30 in response to which the electronic control unit 30
may then activate another drive mechanism to automatically adjust
the angle .theta. of the stringing platform 26 to achieve a
preferred angle of the stringing platform 26 also based on
pre-programmed data correlating user height with a comfortable
turntable height and angle at which to string the racquet 32. This
pre-programmed data may be derived from anthropometric surveys, for
example.
[0072] In a preferred embodiment, the racquet stringing machine 20
is positionable between at least a main stringing position and a
cross string stringing position. The main stringing position
includes a first predetermined height and a first predetermined
angle between the stringing plane and the horizontal surface. In
one particularly preferred embodiment, the first predetermined
height, which is the distance between the horizontal support
surface and the height of the stringing plane (when positioned
horizontally), is approximately 42 to 45 inches, and the first
predetermined angle is approximately 10 degrees.
[0073] The cross string stringing position includes a second
predetermined height and a second predetermined angle between the
stringing plane and the horizontal surface. The second
predetermined height is different from the first predetermined
height, and wherein the second predetermined angle is different
from the first predetermined angle. In one particularly preferred
embodiment, the second predetermined height, which is the distance
between the horizontal support surface and the height of the
stringing plane (when positioned horizontally), is approximately
45.1 to 51 inches, and the first predetermined angle is
approximately 12-15 degrees.
[0074] The racquet stringing machine 20 can also be positionable in
a racquet mounting position, and the racquet mounting position
includes a third predetermined height and a third predetermined
angle between the stringing plane and the horizontal surface. The
third predetermined angle is different from the first and second
predetermined angles, and the third predetermined height is
different from the first and second predetermined heights. In one
particularly preferred embodiment, the third predetermined height,
which is the distance between the horizontal support surface and
the height of the stringing plane (when positioned horizontally),
is approximately 40-41 inches, and the first predetermined angle is
approximately 0 degrees, such that the racquet is horizontal when
mounted onto the stringing machine. The values of the first, second
and third predetermined heights and the first, second and third
predetermined angles are entirely configurable and can be adjusted
or varied to accommodate a particular application, user or group of
users. The amounts listed above are examples only, and are not
intended to be limiting.
[0075] The block diagram in FIG. 15 illustrates a variety of screen
displays that may be prompted by the control unit. As shown, the
control unit 30 may begin by requesting data and user preferences
from a particular user, such as asking the user to select a
language. The control unit 30 may be pre-programmed to function in
one or more languages, for example, in English, Spanish, German,
French, Italian, and Japanese. Subsequently or alternatively, the
control unit 30 may perform a diagnostics check, followed by
self-calibration. FIG. 16 illustrates an example of a screen
display that may appear following a successful diagnostics check.
As indicated in FIG. 16, the user may have the option of using the
stringing machine in a traditional manner, namely without any
automatic adjustments of any of the machine parameters.
[0076] FIG. 17 illustrates an example of a screen display
associated with the selection of a user profile. If one or more
user profiles is already set up, the user may select his or her
profile by touching the appropriate region of the screen display
such as region 88 for a particular user and have the control unit
30 adjust the stringing machine 20 accordingly. Each user may use a
different language, if desired. If the user is a new user, a new
profile may be set up. Alternatively, for returning users, the
machine will default to the programmed preferences of a particular.
Further, one or more features of the automated systems may be
overridden and manual adjustments may be made, if desired, either
before or during the stringing process. As another alternative, one
or more pre-set profiles may be provided as options that are
available to any user. FIG. 18 illustrates an example of a screen
display providing the user with a variety of preferences that may
be set up or changed, such as cross-string and main-string tension
preferences 90, pre-stretch preferences 92, metric/English unit
preferences 94, tension puller speed preferences 96, string tension
indication preferences 98, and knot tension preferences 100. The
option to override settings may be available at essentially every
stage of the stringing process.
[0077] The personal profiles may be stored by the user's initials,
and may include the user's height, language preference,
metric/English units preference, a preference of displaying either
target tension or real-time (i.e., ramping up) tension while the
machine is tensioning the strings, a preferred knot tension, a
pre-stretch preference, same or reduced tension in the cross
strings preference, tournament settings, or other stringing pattern
preference. For example, some users may opt to have increased
tension in the string when tying the knot, with the last string
being pulled at 5-10% greater tension. The increased knot tension
allows the string to relax a bit after the knot is tied, thus
resulting in a tension in the last string that is essentially
equivalent to the tension in the other strings.
[0078] Many users opt to have a stringing machine pre-stretch the
strings, with up to about 20% more tension, which is carried out by
a slow stretch followed by faster stretching. For example, the
pre-stretching procedure may include an initial pull with 10% more
tension, namely with an initial pull to 55 pounds (lbs.), followed
by relaxation, and then a subsequent pull to 50 lbs. As another
example, the pre-stretch procedure may include an initial pull to
55 lbs., followed by a pull to a lower amount such as 30 lbs.,
followed by a pull back to 55 lbs. The actual stretch amounts may
be customized by the user. Pre-stretching typically results in a
more accurate and sustainable tensioning of the strings. Many users
also opt to have the cross strings strung at a lower tension, such
as about 2 lbs. lighter than the main strings, which equalizes the
face of the racquet 32 and also facilitates removal of the racquet
32 from the stringing machine 20 upon completion of the stringing
process. Additionally, the control unit 30 may provide the user
with the option of adjusting the tension during one or more steps
in the stringing process. As illustrated in FIG. 19, the display
may include a touch pad on which the user can adjust tension
settings by pressing on upper or lower portions of the displayed
number 102. For example, in FIG. 19, if a user touches the upper
portion of the number "05" as displayed on the display screen, the
displayed value and the level of tension will increase. Likewise,
if a user touches the lower portion of the number "05" in FIG. 19,
the displayed value and the level of tension will decrease to "04%"
or "03%" or whatever value the user selects. As illustrated in FIG.
20, the user may also adjust the position of the stringing platform
26 during various steps of the stringing process by pressing arrows
104 up or down.
[0079] Other options available to the user may include options for
indicating that the target tension has been reached. For example, a
load cell 108 (FIG. 21) can produce a signal that results in
beeping or other auditory indicator, flashing lights such as along
beveled edges with an LED or other visual display, both audio and
visual indicators, or simply having the machine stop at the target
tension. The user may elect a single tension notification signal of
their choice, or any two or more of the signals to be used
simultaneously. Additionally, the user may be able to adjust the
level of the indicator, such as the volume of an auditory indicator
or the brightness of a visual indicator.
[0080] The user profile can be directed toward a user of the
stringing machine or to a player. In other words, the user profile
can include characteristics desired by a particular player, string
tension and customized stringing instructions can be incorporated
into a particular player profile. The user of the machine can then
pull up or refer to the player's profile when stringing one or more
racquets for the particular player. Alternatively, the player can
utilize his or her own profile when stringing the racquet with the
stringing machine.
[0081] The control unit 30 may also include software that is
capable of tracking the number of string pulls performed by a
particular user over a particular time interval, the amount of time
it takes to string each racquet, the number of racquets strung, and
the average time it takes to string each racquet. Accordingly, the
control unit 30 can be used to record the stringing history of the
stringing machine 20 as a whole, or that of particular users. Such
information could potentially be used to gauge the duration of a
particular racquet stringing period, the productivity of a
particular stringer, and/or the overall use of the machine.
[0082] The electronic control unit 30 may contain a variety of
additional features that enhance the functionality of the machine
20. For example, the unit 30 may include a universal serial bus
(USB) interface that is compatible with such devices as MP3
players, speakers, personal digital assistants (PDAs), gaming
devices, and virtually any other device with a USB connector.
Additionally, the unit 30 may include a USB to SD card reader, or
SD card interface. With an SD card reader, a program on the card
can be run when the card is present, and when the card is removed
the main computer within the control unit 30 will be the program
source. The SD card reader can be used to correct programs and
upgrade software, thus allowing the control unit 30 to be updated
without the need to replace the entire stringing machine 20, or
even the entire electronic control unit 30. The control unit 30 may
also include one or more built-in speakers 86, A/V jacks, and/or a
pocket with a speaker jack. Another feature that may be present on
the control unit 30 is a touch-panel interface 106, as illustrated
in FIGS. 16-20, thus providing a smooth surface with no raised
buttons on the control panel. FIG. 21 is a block diagram
illustrating how various features of the stringing machine 20 may
be connected to the control unit 30.
[0083] As illustrated in FIG. 22, the electronic control unit 30
can be modular. As used herein, the term "modular electronic
control unit" refers to a device that can be easily inserted into
and removed from the stringing machine 20, as illustrated in FIG.
22, and while inserted can be used to automatically adjust at least
one parameter of the machine 20 in response to a user input. Thus,
if the modular electronic control unit 30 appears to be
malfunctioning, the unit 30 can be easily removed and replaced with
another modular electronic control unit 30. The ease of removal of
the unit 30 simplifies potential repairs to the machine 20 by
allowing the user to remove the unit 30 and ship just the unit 30
to the manufacturer or other repair location, rather than requiring
the entire stringing machine 20 to be shipped to the manufacturer
or other repair location. The control unit 30 can also be
configured to be portable so as to move with a particular stringer,
user or player from one location to another or from one stringing
machine 20 to another.
[0084] Additionally, the stringing machine 20 may include an
external power source 110 operatively attached to the electronic
control unit 30, as illustrated in FIG. 9, for example. By locating
the power source 110 outside the body of the stringing machine 20,
this configuration may facilitate importation procedures concerning
approval of electrical devices.
[0085] The invention also presents a method of controlling tension
in a racquet 32 while stringing a racquet 32 using a racquet
stringing machine 20 as described herein. More particularly, the
method includes securing a racquet 32 to the stringing platform 26
of a racquet stringing machine 20 and selecting a stored user
profile in an electronic control unit 30 operably coupled to the
stringing platform 26, in response to which the electronic control
unit 30 generates a first signal to automatically adjust tension in
the string. As described in greater detail above, the user strings
main strings in the racquet 32, guides the string through a tension
puller 60, strings cross strings in the racquet 32, and again
guides the string through the tension puller 60. The electronic
control unit 30 may pre-stretch the string, depending on the user's
preferences. As also described above, the user may adjust tension
in the string by pressing an adjustment indicator on a display
operably connected to the electronic control unit 30.
[0086] Referring to FIGS. 1, 9, 21 and 26, the present invention
also provides a customized racquet stringing system for a racquet,
such as the racquet 32. The racquet 32 includes the string bed 15
of racquet string formed of the plurality of main string segments
16 and the plurality of cross string segments 17. The customized
racquet stringing system includes the racquet stringing machine 20
and the control unit 30. The puller motor 58 of the stringing
tensioning assembly 52 is configured to receive one or more string
tension control signals.
[0087] The control unit 30 includes one or more processing units
120 and associated memory 122. For purposes of this application,
the term "processing unit" shall mean a presently developed or
future developed processing unit that executes sequences of
instructions contained in the memory 122. Execution of the
sequences of instructions causes the processing unit to perform
steps such as generating control signals. The processing unit 120
can include a central processing unit, such as, for example, a
32-bit processor. The instructions may be loaded in a random access
memory (RAM) for execution by the processing unit from a read only
memory (ROM), a mass storage device, or some other persistent
storage. In other embodiments, hard wired circuitry may be used in
place of or in combination with software instructions to implement
the functions described. For example, control unit 30 may be
embodied as part of one or more application-specific integrated
circuits (ASICs). Unless otherwise specifically noted, the control
unit 30 is not limited to any specific combination of hardware
circuitry and software, nor to any particular source for the
instructions executed by the processing unit.
[0088] The memory 122 can provide instructions to the processing
unit 120, and can include one or more computer readable programs or
algorithms. The memory 122 can include computer readable
instructions, such as software code, configured to direct the
operation of the one more processors.
[0089] The control unit 30 can include a first communications port
124 for receiving and/or transmitting signals representative of
data, programs and instructions. The first communications port 124
can be one of many forms and include one or several communications
ports of different configurations or types. The first
communications port 124 can be one or more of any of the following
structures, a USB interface 126, a SD card interface 128, a
wireless receiver 130, a cellular phone dock 132, a CD reader 134
and a DVD reader 136. A communication link 140 can be established
between the one or more first communication port 124. The
communication link 140 can include direct mechanical or electrical,
optical, wired, or wireless communication circuits that can form a
communication link via direct engagement, hard-wired connections,
the Internet, WiFi, LAN, Bluetooth, or other network or a
combination of these. The communication link 140 can be used to
download or otherwise transmit signals from a variety of input
sources such as telecommunication devices and electronic storage
devices. Examples of such devices include one or more of the
following, a cellular phone 142, a PDA 144, a flash drive 146, a CD
148, a DVD 150 and combinations thereof.
[0090] The memory 122 can store the collected racquet, user and
player data. The memory 122 can also be used to store program
modules, such as an operating system, application programs and
stringing algorithms. The racquet stringing algorithms or programs
can incorporate racquet head profiles, user profiles and/or player
profiles to provide instructions on the stringing of each
individual main string segment 16 and cross string segment 17.
[0091] Racquet head profiles can be a list of information relating
to a particular make (supplier or manufacturer), model, and/or
model year of a racquet, and can incorporate racquet
characteristics such as head size, head shape, the head geometry
(such as, for example, the cross-sectional shape of the hoop or
head portion of the racquet), material, weight, balance point,
moment of inertia. The racquet head profile can also include
information such as the number of main string segments the racquet
head is configured to support, the position of each main string
segment relative to the other main string segments or to the
racquet, the position of each cross string segment relative to the
other cross string segments or to the racquet, the number of cross
string segments the racquet head is configured to support, the
recommended string tension for the racquet by the racquet supplier,
the maximum recommended string tension for the racquet by the
racquet supplier, and combinations thereof.
[0092] Player characteristics from a player's profile can also be
incorporated into such stringing programs or algorithms. For
example, if the player prefers a generally higher tension or lower
tension. Also, the typical location that the player or user hits
the ball during play. Further, user profile information can also be
incorporated into the stringing program or algorithm.
[0093] The control unit 30 can be configured to execute a string
tensioning program and to provide a plurality of the string tension
control signals based off of the string tensioning program to the
string tensioning assembly. The plurality of string tension control
signals can correspond to at least three separate string tension
values applied to the plurality of main string segments and/or the
plurality of cross string segments during the stringing of the
racquet. The control unit can provide a specific string tension
signal for each of the main string segments and/or each of the
cross string segments based upon the string tensioning program. In
one preferred embodiment, the string tension signals provided by
the control unit 30 for the main string segments 16 can correspond
to at least two different string tension values. In an alternative
preferred embodiment, the string tension signals provided by the
control unit 30 for the main string segments can correspond to at
least three different string tension values. Likewise, in other
preferred embodiments, the string tension signals provided by the
control unit 30 for the cross string segments correspond to at
least two, or at least three, different string tension values.
[0094] The string tensioning program or algorithm based upon a
particular racquet profile or racquet characteristics, a particular
player's characteristics, or for a particular application or player
level can provide discrete and specific string tension signals
through the control unit 30 to the string tensioning assembly 52 to
apply a specific tension value to each of the main cross string
segments 16 and/or each of the cross string segments 17. The
tension values can be the same for each of the main string segments
16 and each of the cross string segments 17. Alternatively, the
tension value for each individual main string segment 16 and each
individual cross string segment 17 can be different or unique.
Further, any combination of tension values among the main and cross
string segments 16 and 17 can also be applied. So, if a racquet has
16 main strings, the customized stringing system can apply up to 16
different string tension signals corresponding to 16 different
string tension values to the 16 main string segments. The string
tension signals can also be the same, two different signals, three
different signals, four different signals, and so on up to 16 for
that particular racquet. The same would apply to the cross string
segments 17. If the particular racquet had 18 cross string
segments, then the customized stringing system can apply up to 18
different string tension signals corresponding to 18 different
string tension values to the 18 cross string segments. The string
tension signals can also be the same, two different signals, three
different signals, four different signals, and so on up to 18 for
that particular racquet.
[0095] The control unit 30 can be configured to implement a single
string tension program or algorithm or to implement or execute a
variety of different algorithms or programs. The programs or
algorithm can apply entirely different approaches toward the
arrangement of string tension values about a particular string bed
of a racquet.
[0096] The stringing machine 20 and control unit 30 greatly
facilitates the ability of a user, stringer or player to apply a
customized string tension configuration to the string bed of a
racquet. The stringing machine 20 can receive, store, determine,
and/or implement a customized stringing configuration for a
particular racquet based upon one or more algorithms stored within,
received by, or communicated with, the stringing machine 20. For
example, the stringing machine 20 can implement a unique and
customized stringing arrangement for a Wilson.RTM. Six.One.TM.
BLX.RTM. 16.times.18 racquet. This racquet has a head size of 95
square inches, 16.times.18 string pattern (16 main string segments
and 18 cross string segments) and a recommended string tension
range of 50 to 60 lbs. The customized stringing of this racquet
could include the following configuration for the main string
segments 16 and cross string segments 17. This example is
illustrative only. The central-most pair of main string segments
could be pulled to a string tension of 60 lbs, the pair of main
string segments on either side of the central-most pair main string
segments can be pulled to a tension of 58 lbs, the next pair of
main string segments on either side of the prior pair can be pulled
to a tension of 57 lbs, the next outer pair could be strung at 56
lbs, the next pair at 55 lbs, the next pair at 54 lbs, the next
pair at 53 lbs, and finally the two outer-most main string segments
can be pulled to a tension of 52 lbs. The cross string segments can
then be strung to a unique tension configuration. The six
central-most cross strings can be strung at 60 lbs, the two cross
string segments above and below the four central-most cross string
segments can each be strung to 58 lbs, the next two cross string
segments above and below the prior group can be strung at 56 lbs,
the next two cross string segments can be strung at 54 lbs. Any
number of different string tension combinations for the various
main and/or cross string segments can be applied and are
contemplated under the present invention. Different algorithms can
apply different combinations of tension values for different
racquets, for different players, and/or for different applications.
The algorithms could have different characteristics for a 95 square
inch head size versus a 110 square inch head size, or for a
Wilson.RTM. BLX.RTM. versus a Wilson.RTM. (K)Factor.RTM. racquet,
or for a more advance player versus a beginner, or a player who
prefers a softer feel versus a stiffer feel, or a player who
desires more control versus more power, or any combination
thereof.
[0097] In one preferred embodiment/method, the stringing system
with the stringing machine 20 and the control unit 30 allows a
stringer or user of the machine to simply enter some combination of
characteristics such as those discussed above (brand name, model,
player skill level, desired feel, head size, string pattern, etc.).
The stringing system can then apply an algorithm or program to the
selected group of characteristics and select a recommended
customized string tension pattern. Then, the stringer strings the
racquet in accordance with this pattern. The stringing machine
automatically applies the correct desired customized tension values
to each of the main string segments and the cross string segments,
making the performance of customized stringing of a racquet quick,
efficient, effective and repeatable. The stinger or user simply
follows the order specified by the machine and indicates when a
particular string segment is ready for tensioning. In this manner,
the stinger does not have to perform any calculations, does not
have to track what tension applies to what string segment, etc. The
stringing machine executes the program determines and tensions each
string segment to the correct tension value throughout the
stringing of the string bed. The stringing machine can store and
execute any number of different stringing algorithms or receive
specific algorithms from a remote communication device and execute
the algorithm in accordance with the desired characteristics.
[0098] By varying the string tension of the main and cross string
segments 16 and 17 as they are strung by the stringing machine 20,
the performance and responsiveness of the string bed 15 and the
racquet 32 can be significantly changed and improved. For example,
a racquet strung in a conventional manner with one string tension
value applied to the main and cross string segments will typically
have a center of percussion (COP) and a "sweet spot (or region)" at
different locations on the string bed 15. The center of percussion,
COP, is also known as the center of oscillation or the length of a
simple pendulum with the same period as a physical pendulum as in a
racquet oscillating on a pivot. The sweet spot is typically defined
as the area of the string bed 15 that produces higher (or the
highest) coefficient of restitution ("COR") values. A higher COR
generally directly corresponds to greater power and greater
responsiveness. The COP is typically positioned further away from
the handle portion 13 of the racquet 32 on the string bed 15 than
the sweet spot. However, by adjusting, varying and/or optimizing
the application of string tension values to the various main and
cross string segments 16 and 17 comprising the string bed 15, the
position of the sweet spot can be moved to be more in line with the
COP. The sweet spot is thereby repositioned further up the string
bed away from the handle portion 13 and in line with the COP to
provide optimized performance for a particular player.
[0099] In other examples, the customized application of a plurality
of string tension values to the main and/or string segments can
simply produce a more active, responsive and playable racquet. The
feel of the racquet can also be significantly improved by adjusting
the stringing tension of the main and cross string segments of most
racquets.
[0100] Upon execution of a string tensioning program, the control
unit 30 can provide a plurality of the string tension control
signals to the string tensioning assembly 52. The puller motor 58
of the string tensioning assembly 52 can be operated to move the
string puller head 56 away from a head portion 12 of the racquet 32
to produce the desired tension on one of the main string segments
or one of the cross string segments being strung. Movement of the
string puller head 56 can correspond to a specific string tension
control signal from the control unit 30. This process is then
repeated for the other main and cross string segments 16 and 71. As
stated above, the tension value applied to the particular main or
cross string segment 16 and 17 can be the same as other string
segments or unique and separate. The pre-tension preferences of the
user can also be incorporated into the customized stringing.
[0101] In one alternative preferred embodiment of the present
invention, the stringing machine 20 can be used to measure the
shape and/or size of the head portion of the racquet 32 placed onto
the stringing machine 20 for stringing. The frame clamps 70 include
can sensors 170 for measuring the shape and size of the head
portion 12 of the racquet 32. The sensors 170 are coupled to the
frame clamps 70 and are operably coupled to the control unit 30.
Each of the sensors 170 can provide at least one frame clamp signal
to the control unit 30, and the control unit 30 can use the frame
clamp signals to measure the size and shape of the head portion 12,
and to produce at least part of a racquet head profile.
[0102] FIGS. 27-29 illustrate the stringing of main and cross
string segments 16 and 17 on the head portion 12 of the racquet 32.
Referring to FIGS. 27, the main string segments 16 of the string
bed 15 are typically first strung on the head portion 12. A coil of
racquet string 180 is strung through the string holes 19.
Preferably the first string end 182 is threaded through one of the
pairs of the string holes 19 nearest to the longitudinal axis CL of
the head portion 12, thereby forming one of the centermost main
strings. The first string end 182 is typically threaded in the
direction of arrow a from the lower end to the upper end of the
head portion 12. In other embodiments, the main string segment can
be strung in the opposite direction, and/or the first main string
segment can be strung further away from the longitudinal axis
CL.
[0103] Referring to FIGS. 28, the main string segments 16 can be
strung by threading the opposite end 184 of the string coil 180
through the other centermost pair of main string holes 19 to form a
second centermost main string segment 16. The remaining main string
segments are strung by threading the string ends 182 and 184 in a
generally alternating fashion one string at a time or in
alternating groups of 2, 3 or 4 string segments. Arrows c, d, e and
f indicate the continued progression or direction of the first
string end 182 forming one-half of the main string segments 16 of
the string bed. After threading the first half of the main strings,
the first string end 182 is then tied off into a first knot 186,
and any remaining string is cut off. Arrows b, g and h indicate the
continued progression of the second end of the string 184 forming
the remaining half of the main string segments. The second end of
the string 184 can then be used to string the cross-string segments
17. In some instances the second end 184 can be tied off can cut
and a new section (or a different string) can be used to string the
cross string segments 17.
[0104] Referring to FIG. 29, the continued progression of the
second end 184 in forming the cross string segments 17 of the
racquets bed 15 is illustrated. Arrows h through m illustrate the
continued path of the second end 184 through the string holes 19 to
form the cross string segments 17 of the string bed 15. Once all
the cross string segments are threaded, the second end 184 is tied
off into a second knot 188.
[0105] FIGS. 28 and 29 illustrate the main and cross string
segments 16 and 17 in an un-tensioned condition for the purpose of
indicating the full travel of the racquet string forming the string
bed 15. During a typical stringing process, the stringing machine
20 is used to apply the desired amount of tension to each of the
main and cross string segments 16 and 17 (including any pre-tension
preferences of the user) as each of the string segments is strung
through its corresponding set of string holes.
[0106] Referring to FIGS. 1, the racquet 32 is secured onto the
turntable 54 of the stringing platform 26 by the frame clamps 70.
One or both of the string clamps 72 are employed to releasably
secure one portion of the racquet string as another portion of the
racquet string is placed into the puller head 56, as shown in FIG.
11 A. The puller head 56 releasably secures the other portion of
the racquet string as the puller motor 58 then drives the puller
head 56 away the head portion 12 to apply tension to the particular
string segment. Once the desired string tension is applied to the
specific string segment, one or more of the string clamps 72 can be
repositioned to retain the tensioned string as the next string
segment is strung and readied for tensioning. The turntable 54 is
rotatable to align the racquet 32 with the puller head 56 for the
stringing of the entire string bed 15. When the customized
stringing system is used, the control unit 30 sends a specific
string tension signal to the puller motor to apply the desired
level of tension to the specific string segment. This process is
repeated for the remaining string segments, and as stated above,
under the present invention the stringing machine 20 can apply
different tension values to the remaining main and cross string
segments 16 and 17. Accordingly, with the stringing system of the
present invention, the stringing machine 20 and the control unit 30
enables a user to implement and execute any customized stringing
algorithm for any racquet based upon desired characteristics
easily, effectively and efficiently.
[0107] Any one or more of the stringing machine embodiments
described herein may be applied to machines for stringing tennis
racquets, racquetball racquets, squash racquets, badminton
racquets, and any other strung racquet. In particular, the
stringing machine 20 may be used to string racquets for use in an
organized professional league and/or in competitive play.
Furthermore, the stringing machine 20 may be configured to string
racquets in a manner that meets ITF Rules of Tennis requirements
for racquet strings. Regardless of the type of racquet 32,
compatibility of the stringing machine 20 with the user is greatly
improved by using any of the stringing machine enhancements in this
invention.
[0108] The stringing machine of the present invention provides
users with a customized and readily adjustable stringing
experience. The stringing machine enables a particular user to
position the racquet stringing platform in an optimum position for
each portion of the stringing process, thereby reducing stringer
fatigue. The stringing machine of the present invention can
increase the efficiency of the stringing process. The stringing
machine readily adjusts to the preferences of multiple users
thereby improving the effectiveness and efficiency of all
users.
[0109] While the preferred embodiments of the invention have been
illustrated and described, it will be appreciated that various
changes can be made therein without departing from the spirit and
scope of the invention. For example, while the embodiments
described herein are illustrated in a stringing machine for
stringing a tennis racquet, the principles of the present invention
could also be used for stringing machines for stringing practically
any other type of racquet. Accordingly, it will be intended to
include all such alternatives, modifications and variations set
forth within the spirit and scope of the appended claims.
* * * * *