U.S. patent application number 13/857803 was filed with the patent office on 2014-10-09 for shock and vibration attenuating device for sports equipment.
The applicant listed for this patent is Roland Wilfried Sommer. Invention is credited to Roland Wilfried Sommer.
Application Number | 20140302952 13/857803 |
Document ID | / |
Family ID | 51654839 |
Filed Date | 2014-10-09 |
United States Patent
Application |
20140302952 |
Kind Code |
A1 |
Sommer; Roland Wilfried |
October 9, 2014 |
Shock and Vibration Attenuating Device for Sports Equipment
Abstract
A shock and vibration attenuating device is inserted into or
attached to the stroke portion of sports equipment and provided
with a chamber carrier and mass particles dispersed in one or more
chambers formed into the chamber carrier. The inner surface of the
chambers and the mass particles are coated with an electrically
conductive material layer to prevent the particles from clinging
together or clinging to the inner surface of the chambers, so that
the particles are able to move freely within the chambers to
attenuate the shock and vibrations of the sports equipment caused
by reacting-force during stroke.
Inventors: |
Sommer; Roland Wilfried;
(Taichung City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sommer; Roland Wilfried |
Taichung City |
|
TW |
|
|
Family ID: |
51654839 |
Appl. No.: |
13/857803 |
Filed: |
April 5, 2013 |
Current U.S.
Class: |
473/521 ;
473/520 |
Current CPC
Class: |
A63B 49/02 20130101;
A63B 53/08 20130101; A63B 21/0603 20130101; A63B 60/54
20151001 |
Class at
Publication: |
473/521 ;
473/520 |
International
Class: |
A63B 59/00 20060101
A63B059/00; A63B 49/02 20060101 A63B049/02 |
Claims
1. A shock and vibration attenuating device for sports equipment
being inserted into or attached to a stroke portion of the sports
equipment comprising: A chamber carrier with two lateral edges, a
plurality of holes between the two lateral edges; a single chamber
or one or more rows of chambers alternatively arranged with respect
to the holes and located along the two lateral edges in a
protruding manner, an inner surface of each of the chambers being
coated with a layer of electrically conductive material; and a
single or a plurality of mass particles, each of the chambers being
partially filled with the mass particles, each of the mass
particles being coated with a layer of electrically conductive
material, each of the chambers being filled with one or more of the
mass particles in such a manner that there is a distance between
the electrically conductive mass particles and the inner surface of
the chambers, allowing the mass particles to move freely within the
chambers to dynamically suppress impact shock during the striking
action and dynamically reduce vibration after the impact.
2. The shock and vibration attenuating device for sports equipment
as claimed in claim 1, wherein the electrically conductive layer on
the inner surface of the respective chambers and the mass particles
are coated by electrically conductive materials, such as graphite,
metal sputtering or galvanic coating processes.
3. The shock and vibration attenuating device for sports equipment
as claimed in claim 1, wherein the travel distance of the mass
particles moving within the chambers during the striking action, is
calculated based on the following equation 1: .DELTA. d m - t c
.DELTA. V m * COR ##EQU00005## Wherein .DELTA.dm represents the
travel distance that the mass particles moves, t.sub.c is the
dwelling time, .DELTA.V.sub.m is the velocity difference of the
sports equipment during the striking action, and COR as the primary
impact systems coefficient of restitution.
4. The shock and vibration attenuating device for sports equipment
as claimed in claim 3, wherein the velocity difference
.DELTA.V.sub.m of the sports equipment during the striking action
is calculated based on the following equation 2: .DELTA. V m = 2 *
m b * V r m b + m r ##EQU00006## wherein m.sub.b is the mass of the
ball, m.sub.r is the mass of the sports equipment, and V.sub.r is
the velocity of the sports equipment.
5. The shock and vibration attenuating device for sports equipment
as claimed in claim 1, wherein the sports equipment is a tennis
racket, golf club, or bat.
6. The shock and vibration attenuating device for sports equipment
as claimed in claim 1, wherein the sports equipment is a ski.
7. The shock and vibration attenuating device for sports equipment
as claimed in claim 1, wherein the sports equipment comprises a
frame connected to a handle when the sports equipment is a tennis
racket, and a string bed provided around an inner periphery of the
frame, the racket frame is further provided with a plurality of
holes, the chamber carrier comprises a first surface and a second
surface which are opposite to each other and connected to the two
lateral edges, the chambers are formed on the first surface of the
chamber carrier in a protruding manner, the chamber carrier is
inserted into the frame of the sports equipment in such a manner
that the first and second surfaces are perpendicular to the string
bed of the sports equipment, and the holes of the chamber carrier
are aligned and connected through the holes of the frame of the
sports equipment.
8. The shock and vibration attenuating device for sports equipment
as claimed in claim 1, wherein the chambers are arranged in two
symmetrical rows along the two lateral edges of the chamber
carrier, and around each of the holes of the chamber carrier are
arranged four said chambers.
9. The shock and vibration attenuating device for the sports
equipment as claimed in claim 1, wherein the chambers are
semispherical in cross section.
10. The shock and vibration attenuating device for the sports
equipment as claimed in claim 1, wherein the chambers are
semicircular, spherical or half spherical in cross section.
11. A shock and vibration attenuating device for sports equipment
being inserted into a stroke portion of the sports equipment
comprising: a chamber carrier with two lateral edges, a plurality
of chambers arranged along the two lateral edges, and in each of
the chambers being disposed one or more mass particles; and the
shock and vibration attenuation device being characterized in that:
an inner surface of each of the chambers is coated with a layer of
electrically conductive materials, each of the chambers are
provided with one or more mass particles, each of the mass
particles is coated with a layer of electrically conductive
materials, there is a distance between the mass particles and the
inner surface of the chambers, allowing the mass particles to move
freely within the chambers to absorb stroke impact caused by a
striking action and reduce shocks caused by the stroke impact.
12. The shock and vibration attenuating device for the sports
equipment as claimed in claim 11, wherein the travel distance that
the mass particles moves within the chambers during the striking
action are matched to the respective impact system which is
calculated based on the following equation 1: .DELTA. d m = t c
.DELTA. V m * COR ##EQU00007## wherein .DELTA.dm represents the
travel distance D that the mass particles moves, t.sub.c is the
dwelling time, .DELTA.V.sub.m is the velocity difference of the
sports equipment during the striking action, and COR is primary
impact systems coefficient of restitution.
13. The shock and vibration attenuating device for sports equipment
as claimed in claim 12, wherein the velocity difference
.DELTA.V.sub.m of the sports equipment during the striking action
is calculated based on the following equation 2: .DELTA. V m = 2 *
m b * V r m b + m r ##EQU00008## wherein m.sub.b is the mass of the
ball, m.sub.r is the mass of the sports equipment, and V.sub.r is
the velocity of the sports equipment.
14. A shock and vibration attenuating device for sports equipment
being inserted into a frame or attached alongside the frame of a
tennis racket comprising: a chamber carrier with two lateral edges,
a plurality of holes between the two lateral edges; one or more
chambers alternatively arranged with respect to the holes and
located along the two lateral edges in a protruding manner, an
inner surface of each of the chambers being coated with a layer of
electrically conductive materials; and one or more mass particles,
each of the mass particles being coated with a layer of
electrically conductive materials, each of the chambers being
filled with one or more mass particles in such a manner that there
is a distance between the mass particles and the inner surface of
the chambers, allowing the mass particles to move freely within the
chambers to absorb stroke impact caused by a striking action and
reduces shocks caused by the stroke impact.
15. The shock and vibration attenuating device for the sports
equipment as claimed in claim 14, wherein the tennis racket
comprises a frame connected to a handle, and a string bed provided
around an inner periphery of the frame, the frame is further
provided with a plurality of holes, the chamber carrier is provided
with a first surface and a second surface which are opposite to
each other and connected to the two lateral edges, the one or more
chambers are formed on the first surface of the chamber carrier in
a protruding manner, the chamber carrier is inserted into the frame
of the tennis racket in such a manner that the first and second
surfaces are perpendicular to the string bed of the tennis racket,
and the holes of the chamber carrier are aligned and connected
through the holes of the frame of the tennis racket.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a shock and vibration
attenuating device for sports equipment, and more particularly to a
shock and vibration attenuating device to be inserted in the sports
equipment which have a handle and a stroke portion.
[0003] 2. Description of the Prior Art
[0004] When a force is applied to make two objects collide with
each other, it will produce two reacting forces on the two objects.
Therefore, for ball games such as tennis, badminton, baseball,
golf, cricket and polo or even skiing etc, the ball hitting or the
skiing action shall be performed by a player by hitting the ball or
the ground with one hand holding the sports equipment (the
equipment may be the bats, clubs, rackets or ski poles etc.). When
the sports equipment collides the ball, there will be a reacting
force conveying to sports equipment and causes a high energetic
shock impulse and vibration. The high energetic shock impulse and
the vibration would be transmitted to the hand holding the sports
equipment via the handle of the sports equipment, and this is the
cause of the "tennis elbow" and similar injuries.
[0005] For this reason, manufacturers of related sports equipment
have been searching for constructional possibilities to attenuate
the vibration and absorb the shock generated by kick-back by
rackets. As shown in FIGS. 1 and 2A, a conventional tennis racket
10 is provided with a plurality of chambers 11 with the opening
closed by a removable stopper 12 and filled with movable masses,
such as mass particles 13 or liquid (not shown) of high specific
weight. During a striking action, the mass particles 13 or liquid
will move freely within the chambers 11 along with the movement of
the tennis racket 10 to generate a counter force interfering with
the reacting-force caused shock impulse and oscillation waves, so
that the shock impulse and oscillation waves caused by reacting
force would be attenuated before being transmitted to the player's
hand, which therefore effectively reduces injuries to the player's
wrist.
[0006] However, the attenuation of the high energetic impact shock
impulse in previous mass system is limited. To match the contact
time of different impact systems, the single chambers (10) should
be filled partially to allow for a free movement of either the
filled-in mass particles or a heavy liquid. The heavier the
specific weight of the mass particles or the liquid is; the better
the efficiency of the generated impact counter force will be during
impact. When liquid or mass particles are moving within the
chambers during impact, the electro static phenomenon on the
surface of chambers usually results in the difficulty of movement
or malfunction of mass particles. Hence, shock impulse suppression
and the vibration attenuation effect would be affected by the said
difficulty or malfunction.
[0007] The problem of electro static charges are illustrated in
FIGS. 2A-2D and FIGS. 3A-3D. FIGS. 2A and 3A show that the mass
particles 13 are gathered at the right side of the chamber 11 when
the tennis racket 10 is swung in the direction indicated by the
arrow 1, and further at the initial stage when the ball 2 just
contacts with the tennis racket 10. FIGS. 2B and 3B indicate that
the mass particles 13 start moving from the right side to the left
side of the chamber 11 during impact when the ball 2 collides with
the tennis racket 10 and slightly deforms. To finally have a
secondary time delayed impact, generating the counter directed
impact impulse to suppress the initially generated impact shock
impulse within the impact system is desired.
[0008] FIGS. 2C and 3C further illustrate the midpoint between the
time when the ball 2 touches and rebounds from the tennis racket
10. The deformation of the ball 2 in FIGS. 2C and 3C is more
apparent as compared with the balls as shown in FIG. 3B, and the
mass particles 13 move to the left side of the chamber 11. FIGS. 2D
and 3D show the time point when the ball 2 rebounds from the tennis
racket 10, wherein the vibration caused by reacting force
after-collision will be transferred to the mass particles 13 via
the wall of the chamber 11, causing the mass particles 13 to move
from the left side to the right side of the chamber 11. In this
way, the mass particles 13 move back and forth freely in the
chamber 11 to absorb shocks of the reacting force and attenuate
oscillation. When mass particles move freely within the chambers,
electro static charges are generated between the mass particles 13
or between the mass particles 13 and the inner surface of the
chamber 11. For this reason, a quantity of mass particles 13 are
clinging to the inner surface of the chamber 11 due to electro
static charges every time when the mass particles 13 move within
the chamber 11 (as shown in FIGS. 2A-2D). Furthermore, only a small
amount of mass particles 13 will be actively involved in the
secondary impact process because of the static electricity and the
clinging effect, in turn eliminating the efficiency of the
secondary impact. In comparison with a dynamic system with all of
the particles moving freely at all, the shock impulse and the
vibration of the tennis racket 10 in prior art cannot not be fully
attenuated. As such, the present invention has arisen to mitigate
and/or obviate the afore-described disadvantages.
SUMMARY OF THE INVENTION
[0009] The primary objective of the present invention is to provide
a vibration attenuating device for sports equipment, which is
capable of effectively absorbing shock and reducing the vibrations
of the sports equipment dynamically during the hitting action.
[0010] To achieve the above objective, a shock and vibration
attenuating device for sports equipment in accordance with the
present invention is inserted into a stroke portion or the handle
of the sports equipment. The present application introduces a
device comprising a chamber carrier which is provided with two
lateral edges, and a plurality of holes between the two lateral
edges for better fixation within a composite- or other structure.
One or more chambers are alternatively arranged with respect to the
holes and located along the two lateral edges in a protruding
manner. And the inner surface of each of the chambers is coated
with a layer of electrically conductive material. Moreover, each of
the chambers is filled with coated mass particles in such a manner
that there is a distance left between mass particles and the inner
surface of the chambers, allowing the mass particles to move freely
within the chambers to produce efficient dynamic energy to absorb
impacts caused by a hitting action and attenuate shock caused by
the impact with the ball.
[0011] Preferably, the shock and vibration attenuating device is
inserted into the frame of a tennis racket, with the electrically
conductive layers coated on the inner surface of the respective
chambers and the mass particles inside the chambers are anti-static
based on electrically conductive materials, such as Graphite or
other conductive substances.
[0012] The distance for the mass particles to travel within the
chambers during the hitting action is calculated based on the
following equation 1:
.DELTA. d m = t c .DELTA. V m * COR ##EQU00001##
[0013] Wherein .DELTA.dm represents the travel distance (mm) of the
mass particles, t.sub.c is the Contacting or Dwelling time
(millisecond), .DELTA.V.sub.m is the velocity difference of the
sport equipment during the striking action, and COR is the primary
impact systems coefficient of restitution. The velocity difference
.DELTA.V.sub.m of the tennis racket during the striking action can
be calculated based on the following equation 2:
.DELTA. V m = 2 * m b * V r m b + m r ##EQU00002##
[0014] Wherein m.sub.b is grams of the ball mass, m.sub.r is the
mass of the tennis racket (the sports equipment), and V.sub.r is
the velocity (m/s) of the tennis racket (the sports equipment).
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a perspective view of conventional sports
equipment installed with chambers;
[0016] FIG. 2A is a cross sectional view of a conventional
vibration attenuating device showing the status of the mass
particles when the sports equipment moves toward the ball;
[0017] FIG. 2B is a cross sectional view of a conventional
vibration attenuating device showing the status of the mass
particles when the sports equipment collides the ball;
[0018] FIG. 2C is a cross sectional view of a conventional
vibration attenuating device showing the status of the mass
particles when the ball deforms upon contacting with the
racket;
[0019] FIG. 2D is a cross sectional view of a conventional
vibration attenuating device showing the status of the mass
particles after the sports equipment collides the ball;
[0020] FIG. 3A illustrates the time point when the ball initially
contacts with a tennis racket and rebounds in accordance with the
present invention;
[0021] FIG. 3B illustrates the position when the ball fully
contacts with a tennis racket and deforms in accordance with the
present invention;
[0022] FIG. 3C illustrates position in the process from the timing
when the ball contacts with a tennis racket to the timing when it
rebounds in accordance with the present invention;
[0023] FIG. 3D illustrates position when the ball starts rebounding
in accordance with the present invention;
[0024] FIG. 4 illustrates the shock and vibration attenuating
device for sports equipment in accordance with a preferred
embodiment of the present invention;
[0025] FIG. 5 is perspective view of the shock and vibration
attenuating device for sports equipment in accordance with the
present invention;
[0026] FIG. 6 illustrates that the chambers of the shock and
vibration attenuating device for sports equipment in accordance
with the present invention are semispherical in cross section;
[0027] FIG. 7 is a cross sectional view of the semispherical
chambers of the shock and vibration attenuating device in
accordance with the present invention;
[0028] FIG. 8 is illustrative view of no clinging between mass
particles and walls of chambers in the shock and vibration
attenuating device for sports equipment in accordance with the
present invention;
[0029] FIG. 9 is an enlarged cross sectional view showing the
chambers and mass particles of the shock and vibration attenuating
device for sports equipment in accordance with the present
invention;
[0030] FIG. 10 illustrates that the chambers of the shock and
vibration attenuating device for sports equipment in accordance
with the present invention are semicircular in cross section;
[0031] FIG. 11 is a cross sectional view of the semicircular
chambers of the shock and vibration attenuating device in
accordance with the present invention;
[0032] FIG. 12 is a diagram comparing the energy of a conventional
tennis racket without chambers and invention in present
application;
[0033] FIG. 13 is a diagram comparing the energy of a conventional
golf club without chambers and invention in present
application.
[0034] FIG. 14A is the values of Sweetspot scan by tennis robot for
a conventional tennis racket with chamber without being coated by a
layer of electrically conductive material.
[0035] FIG. 14B is a diagram of Sweetspot scan by tennis robot for
a conventional tennis racket with chambers without being coated by
a layer of electrically conductive material.
[0036] FIG. 15A is the values of Sweetspot scan by tennis robot for
a tennis racket with chamber being coated by a layer of
electrically conductive material in present application.
[0037] FIG. 15B is a diagram of Sweetspot scan by tennis robot for
a tennis racket containing chambers being coated with a layer of
electrically conductive material in present application.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] The present invention will be understood from the following
description when viewed in accordance with the accompanying
drawings, which show, for purpose of illustrations only, the
preferred embodiment in accordance with the present invention.
[0039] Referring to FIGS. 4, 5 and 6-11, a shock and vibration
attenuating device for sports equipment in accordance with a
preferred embodiment of the present invention is being inserted in
a stroke portion of the sports equipment which is to be hold by a
player to strike an object. The sports equipment can be a tennis
racket, badminton racket or a golf club. However, the use of the
shock and vibration attenuating device of the present invention is
not limited to the sports equipment for ball games and is
applicable to any sports equipment as along as the sports equipment
is hold by a player to strike the objects and shock is caused and
transferred to the player's hand during the stroke. For example,
the sports equipment can be ski which start to vibrate during
driving over a rough ice- or snow surface and loosing contact to
the ground. The shock and vibration attenuating device is used to
absorb the stroke energy and attenuate the stroke shock as well as
oscillation caused after the stroke energy acts on the player's
hands, or like in the example, providing for the ski contact to the
ground. FIG. 4 illustrates the invention based on sports equipment
100 which is a tennis racket. The sports equipment 100 comprises a
racket frame 101 connected to a handle 102, and a string bed 103 is
provided along the inner periphery of the racket frame 101. The
racket frame 101 is further provided with a plurality of holes
104.
[0040] Referring to FIGS. 5-7, the shock and vibration attenuating
device in accordance with the present invention is inserted in the
racket frame 101 of the sports equipment 100. and the shock and
vibration attenuating device comprises a chamber carrier 20. The
chamber carrier 20 is further provided with two lateral edges 201,
and a first surface 21 and a second surface 22 which are opposite
to each other and connected to the two lateral edges 201. Between
the two lateral edges 201 is formed a plurality of holes 23. One or
more chambers 30 are arranged along the racket frame with respect
to the holes 23 in a protruding manner. The inner surface of each
of the chambers 30 is coated with a layer of electrically
conductive material 31, and in each of the chambers 30 is provided
a number of mass particles 41. Each of the mass particles 41 is
coated with a layer of electrically conductive material 42. The
mass particles 41 can be made of tungsten or tungsten alloy or
other environmental-friendly materials free of lead and iron, as
shown in FIGS. 7, 8 and 9. However, the material of the mass
particles 41 is not limited to the abovementioned metals. Any
substances with heavy weight can be used as mass particles. After
each of the chambers 30 is partly filled with the mass particles
41, there is a distance D left between the mass particles 41 and
the inner surface of the chamber 30, allowing the mass particles 41
to move freely within the chambers 30 during a stroke. The distance
D is calculated based on equations (1) and (2) of the present
invention, and the configurations of the sports equipment and the
ball. The calculation and the equations will be discussed in detail
as below.
[0041] As mentioned earlier, the shock and vibration attenuating
device of the present invention is applicable to any sports
equipment with stroke portion to strike objects such as ball. For
explanation of the present invention, the description of the
present invention is based on an embodiment in which the sports
equipment 100 is a tennis racket. Referring to FIG. 5, the chamber
carrier 20 is inserted in the racket frame 101 of the sports
equipment 100 in such a manner that the first and second surfaces
21, 22 are perpendicular to the racket surface 103 of the sports
equipment 100, and the holes 23 of the chamber carrier 20 are
aligned and connected through the holes 104 of the racket frame 101
of the sports equipment 100. The strings of the racket surface 103
are set through the holes 23 of the chamber carrier 20 and the
holes 104 of the racket frame 101, forming the racket head for
stroke.
[0042] Referring to FIGS. 8 and 9, in this embodiment, the layers
of electrically conductive materials 31 and 42 are coated on the
inner surface of the respective chambers 30 and the mass particles
41. The layer of electrically conductive maters can be graphite
(preferably nanometer graphite particles) but not limited to
graphite. The layer of conductive material can also be nano
particles of quartz, lime, marble, or powders or liquids formed by
anti-static substances. By taking advantage of the layer of
electrically conductive materials, the problem that the frictions
and static electricity generated between the mass particles 41 or
between the particles 41 and the inner surface of the chambers can
be avoided, which then enhances releasing the energy of freely
movable mass particles. After coating as shown in FIG. 10, the mass
particles 41 are deposited at the lower portion of the respective
chambers 30 because of gravity or typically during play by
acceleration. This eliminates the problem that the mass particles
41 are adhered to the inner surface of the chambers 30 due to
static electricity. As such, the mass particles 41 are able to move
freely within the chambers 30 and release more kinetic energy
during use.
[0043] FIGS. 6, 7, 10 and 11 show another embodiment of the shock
and vibration attenuating device in accordance with the present
invention. According to this embodiment, one or more chambers 30
are arranged in one or more symmetrical rows along with the two
lateral edges 201 of the chamber carrier 20, and around each of the
holes 23 of the chamber carrier 20 are provided with four chambers
30, so that the shock and vibration caused by impact when the ball
touches the sports equipment 100 would be reduced evenly. The
chambers 30 can also be arranged in a single row or alternatively
disposed with respect to the holes 23 of the chamber carrier 20 or
in other shape based on the shaft or stroke portion of the sport
equipment. The chambers 30 can be spherical or semispherical (as
shown in FIGS. 6 and 7) or semicircular (as shown in FIGS. 10 and
11).
[0044] It is to be noted that the distance D that the mass
particles 41 move within the chambers 30 during the striking action
is calculated based on the following equation 1:
.DELTA. d m = t c .DELTA. V m * COR ##EQU00003##
[0045] Wherein .DELTA.dm represents the travel distance (mm) of the
mass particles, t.sub.c is the contact or dwell time (millisecond),
.DELTA.V.sub.m is the velocity difference of the sport equipment
during striking action, and COR is the primary impact systems
coefficient of restitution. The velocity difference .DELTA.V.sub.m
of the sports equipment 100 during the striking action can be
calculated based on the following equation 2:
.DELTA. V m = 2 * m b * V r m b + m r ##EQU00004##
[0046] Wherein m.sub.b is the mass (g) of the ball, m.sub.r is the
mass of the tennis racket (the sports equipment), and V.sub.r is
the velocity (m/s) of the tennis racket (the sports equipment).
[0047] The following is the comparison charts for the sports
equipment with and without installing the present application.
Embodiment 1 is test results of the shock and vibration attenuating
device for sports equipment which is a tennis racket.
[0048] Please refer to FIGS. 3A-3D and 12, FIG. 12 is a graph
illustrating the test results of a striking action of tennis
rackets with and without the present application, wherein ordinate
and abscissa of FIG. 12 are pressure sensor voltage and the time of
impact when ball contacts with the sports equipment (ms). The
curves L1 and L2 represent the test results of the tennis racket
which is provided with the shock and vibration attenuating device
based on the present invention, while curves L3 and L4 represent
the test results of a tennis racket without the shock and vibration
attenuating device based on the present invention. FIG. 12
indicates different vertical lines A, B, C, D and E, wherein the
vertical lines A and E represent start and end of dwelling time
during impact when ball 2 touches on the sports equipment as shown
in FIG. 3A. During the time between the vertical lines A and B, the
ball 2 contacts with the sports equipment and slightly deforms as
shown in FIG. 3B. The vertical line B represents the time point
that Ball flat maximum is formed when the ball 2 contacts with the
sports equipment as shown in FIG. 3C. Furthermore, the vertical
line C represents the half of dwell time after the ball 2 hits on
the tennis racket 10. Finally, the vertical line D represents the
time point when the ball 2 starts rebounding from the sports
equipment affected by the maximum rebounding force as shown in FIG.
3D. At this time point, the ball 2 still stays on the sports
equipment and slightly deforms.
[0049] It is to be noticed that the curve L1 of the sports
equipment provided with the shock and vibration attenuating device
based on the present invention is less steep than the curve L3. And
the amplitude of the curve L2 is much smaller than that of the
curve L4, which means that the shock and vibration attenuating
device of the present invention is dramatically capable of
absorbing the stroke impact and attenuating the vibration caused by
the stroke impact, hence reducing injuries of the player's
hands.
[0050] Embodiment 2 is the test results of the shock and vibration
attenuating device for sports equipment which is a golf club.
[0051] FIG. 13 is a graph illustrating the test results of a
striking action which is conducted by striking a golf ball with the
golf club, wherein the ordinate and abscissa of FIG. 13 are voltage
and the time of impact when ball contacts with the sports equipment
(ms). The curve L5 represents the test results of the golf club
which is provided with the shock and vibration attenuating device
based on the present invention. Moreover, the curve L6 represents
that the voltage values are changed by using the pressure of impact
when the ball hitting on the sports equipment. The curve L6 is used
to detect the start point (the vertical line O in the drawing) and
end point (the vertical line X) of the curve L5 during the
impact.
[0052] As indicated by the curve L5, the vibration wave after
stroke is less steep than the vibration wave during stroke for the
golf club provided with the shock and vibration attenuating device.
This proves that the golf club which is installed with the shock
and vibration attenuating device of the present application is
capable of releasing kinetic energy to absorb the stroke shock and
attenuate the vibration caused by stroke.
[0053] Embodiment 3 are test results of a tennis racket provided
with a conventional vibration attenuating device and a tennis
racket with a shock and vibration attenuating device of the present
invention.
[0054] FIGS. 14 and 15 are sweetspot scan polar diagrams with data
acquired by tennis robot and further calculated by formulas. The
test results of a tennis racket containing mass particles without
being coated with conductive layer are different from and that of a
tennis racket with mass particles 41 being coated with the
conductive layer 42.
[0055] At the top left of FIGS. 14 and 15 are preset border values,
wherein the border value for power zone is 25%, Dynamic Precision
border value is 35%, Dynamic Shock absorption boarder value is 35%,
D-COR boost border value is 38%, and the strung area is 109
in.sup.2.
[0056] The lower left of FIGS. 14 and 15 shows the values obtained
in the tests performed under the above conditions, and the right
sides FIGS. 14 and 15 are corresponding polar diagrams. The Dynamic
Precision Zone (Dyn. Precision Zone) is the part of the tennis
racket which can impart a relatively larger force to the ball when
striking, and the ball can be directed to a desired position
additionally. When the tennis racket is swung within this area, the
player can control the direction of the ball more precisely. The
ball can be played with reasonably higher efficiency and less
effort from the player to reach the same ball velocity. Therefore,
and the shock and the vibration caused by the striking action can
effectively be reduced if the ball impacts the Dynamic Precision
Zone. As a result, the larger the Dynamic Precision Zone is, the
more likely it increases the precision of the ball direction and
reduces sports injuries caused by lateral torque of the racket.
[0057] As shown in FIG. 14A, when using the tennis racket which is
provided with mass particles without being coated with an
electrically conductive layer, the tested Dynamic Precision Zone is
9.83 in.sup.2, which corresponds to the area defined by the symbol
".quadrature.". FIG. 15A shows that the tested Dynamic Precision
Zone of a tennis racket which is provided with mass particles
coated with an electrically conductive layer is 18.26 in.sup.2,
which is almost twice than that of the conventional tennis racket
in FIG. 14A. Besides, the area defined by the symbol ".quadrature."
shown at the right side of FIG. 15B is obviously larger than that
of FIG. 14B. It is obvious that the tennis racket of the present
invention installed with mass particles coated with the
electrically conductive layer provides larger Dynamic Precision
Zone, as such is more capable of reducing shock and vibration to
diminish the sports injuries, such as "tennis elbow".
[0058] The value of Shock abs. Zone (Shock Absorption Zone) shown
at the lower left of the drawings indicates the capability of
absorbing shocks caused by the striking action when swinging
tennis. Hence, the shock can be substantially absorbed if the value
of Shock abs. zone is higher, thus reducing the hurts to the
player. FIG. 14A shows that the Shock abs. Zone of the conventional
tennis racket containing mass particles without coating of
conductive layer is 5.62 in.sup.2. In contrast, FIG. 15A shows that
the Shock abs. Zone of the tennis racket of the present invention
is 10.65 in.sup.2, which is almost twice than that of the
conventional tennis racket. The area of Shock Absorption is defined
by the symbol ".diamond." shown at the right side of FIG. 15B and
this zone is obviously larger than that in FIG. 14B. This proves
that the shock-absorption area can be increased for the tennis
racket installed with mass particles being coated with electrically
conductive layer of the present invention. The increase of the
Dynamic Precision Zone and Dynamic Shock absorption zone both prove
the present invention provides higher effect of attenuating the
reacting-force caused shocks and vibrations of the sports
equipment.
[0059] In general, the electrically conductive layer coated on the
inner surface of the respective chambers 30 and the mass particles
41 prevents the mass particles 41 from clinging together or
clinging to the inner surface of the chambers 30, so that the
kinetic energy of the present invention is increased 60% as
compared to the conventional structure. Besides, the preferable
amounts of chambers and the movement distance D of mass particles
can be calculated based on the above equations 1 and 2. The amounts
of chambers, the configuration of the chambers 30 and movement
distance of mass particles can be adjusted to optimize the effect
of attenuating shocks according to the type of sports equipment.
Therefore, the chambers can be installed as many in relation to the
volume of the stroke portion or the shaft.
* * * * *