U.S. patent number 3,837,655 [Application Number 05/340,648] was granted by the patent office on 1974-09-24 for apparatus for detecting spin of golf ball in indoor golf playing system.
Invention is credited to Arthur C. Angelos.
United States Patent |
3,837,655 |
Angelos |
September 24, 1974 |
APPARATUS FOR DETECTING SPIN OF GOLF BALL IN INDOOR GOLF PLAYING
SYSTEM
Abstract
In an indoor golf playing system, it is very advantageous if a
golfer can determine the amount of side spin, i.e., slice or hook
imparted to the ball. The ball is placed at a known point which is
part of the indoor system and is hit into an impact surface such as
a wall or screen which displays a picture of an appropriate portion
of a golf course as it is seen by a golfer. A row of detectors is
positioned in front of the impact surface and, as the golf ball is
hit toward the surface and crosses the row of detectors, it
actuates one or more of the detectors to produce an output. In this
manner, the path of the ball travelling towards the surface is
detected. The ball, upon hitting the surface, rebounds back toward
the golfer and is again detected by one or more of the detectors as
it passes back through the row of detectors. The angle at which the
ball rebounds from the surface is a function of the side spin
imparted to the ball by the golfer. Therefore, by detecting the
point at which the ball crosses the row of detectors as it travels
toward the surface and comparing this point to the point at which
the ball travels through the row of detectors as it rebounds from
the surface, the amount of side spin can readily be determined. In
the event the golf ball is to be hit from points of origin that may
not be determined, a second row of detectors may be positioned
between the first row of detectors and the points of origin.
Inventors: |
Angelos; Arthur C.
(Springfield, VA) |
Family
ID: |
23334346 |
Appl.
No.: |
05/340,648 |
Filed: |
March 13, 1973 |
Current U.S.
Class: |
473/152 |
Current CPC
Class: |
G01P
3/00 (20130101); A63B 63/00 (20130101); A63B
24/0021 (20130101); A63B 69/0097 (20130101); A63B
2024/0037 (20130101); A63B 2024/0043 (20130101) |
Current International
Class: |
A63B
63/00 (20060101); G01P 3/00 (20060101); A63B
69/00 (20060101); A63B 69/36 (20060101); A63b
069/36 () |
Field of
Search: |
;273/176,184,185,181H |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Marlo; George J.
Claims
What is claimed is:
1. Apparatus for detecting the amount of spin imparted to a ball
when hit in free flight from a point of origin, said apparatus
comprising:
an impact surface positioned in the path of travel of the ball for
rebounding the ball therefrom,
detector means positioned between said point of origin and said
impact surface for detecting the location of a first point at which
the ball passes said detector means as it is travelling in flight
toward said surface, and for detecting the location of a second
point at which the ball rebounding in flight from said impact
surface passes said detector means, without interfering with the
flight of the ball, and
means responsive to the detection of said first and said second
points for determining the amount of spin imparted to the ball.
2. The apparatus of claim 1, wherein said impact surface is
substantially planar.
3. The apparatus of claim 1, wherein said impact surface is a
screen.
4. The apparatus of claim 1, wherein said detector means and said
last-mentioned means are so constructed and arranged to determine
the amount of side spin imparted to the ball.
5. The apparatus of claim 1, wherein said last-mentioned means
comprises indicator means connected to said detector means for
indicating the amount of spin imparted to the ball.
6. The apparatus of claim 1 wherein said detector means comprises a
plurality of sensors arranged in a row.
7. The apparatus of claim 6 wherein said sensors comprise photo
detectors, and means are provided to illuminate said photo
detectors.
8. The apparatus of claim 6 wherein said means responsive to the
detection of said first and second points comprises:
a. resistance means,
b. a plurality of switch means interconnected with said resistance
means, each of said switch means corresponding to one of said
plurality of sensors, whereby detection of the ball by one of said
sensors operates said switch means to thereby change the resistance
of said resistance means,
c. a voltage source connected to said resistance means, and
d. output means for detecting the voltage across said resistance
means which varies in accordance with the variation of the
resistance of said resistance means, said output means producing a
signal indicative of the amount of spin imparted to the ball.
9. The apparatus of claim 8 wherein said resistance means and said
plurality of switch means are interconnected to form a variable
voltage divider having a configuration which changes in accordance
with the operation of said switch means.
10. The apparatus of claim 8 wherein said output means includes
storage means for storing a voltage corresponding to said first
point and for storing a voltage corresponding to said second point,
and means for comparing said stored voltages and for producing an
output indicative of the comparison.
Description
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for detecting the amount of
spin imparted to a golf ball in an indoor golf playing system and,
more particularly, to such an apparatus using an impact surface
such as a screen and a row of detectors spaced from the impact
surface.
Several prior art devices exist for determining the amount of hook
or slice imparted to a golf ball in an indoor golf playing system.
These devices, however, have not been completely satisfactory in
that they have been complicated in construction and expensive to
manufacture, have required complex screen arrangements, have not
been completely accurate or reliable in operation, and have
required extensive maintenance.
In one such device, a spherical shell or screen is used and the tee
for the golf ball is positioned at the center of the sphere. If the
golf ball is hit without side spin, it will hit the screen and
rebound therefrom to the center of the sphere. If however, a side
spin is imparted to the ball, it will not return to the center of
the sphere. By measuring or indicating the point to which the ball
returns, the amount of spin (hook or slice) can be determined. This
type of system is subject to certain disadvantages. If the ball
must roll back towards the center of the sphere before its rebound
position is indicated, it is subject to inaccuracies caused by the
floor surface not being completely level which may affect the roll
and/or bounce of the ball. Furthermore, the construction of a
perfectly spherical screen is difficult and expensive.
Another type of device uses two impact surfaces or screens
positioned at an angle to each other. The ball is hit into one of
the screens and bounces off of that screen onto the second screen.
The points at which the ball strikes the first and second screens
are detected to indicate the amount of spin imparted to the ball.
The geometry of the two screens is such that if a ball having no
side spin strikes the first screen at a first point, it will strike
the second screen at a predetermined second point. If, however,
side spin is imparted to the ball, it will strike the second screen
at a point other than the predetermined second point, and the
difference between the actual second point of contact and the
predetermined point is used to determine and indicate the amount of
hook or slice. This system has the obvious disadvantage that it
requires two accurately positioned and constructed screens rather
than a single screen. This is critical not only because of the
additional expense of a second screen but also because of the
additional space required for the second screen. Space, of course,
is at a premium in an indoor golf playing system. Also, the second
screen may adversely affect, from the standpoint of appearance, the
simulation of actual golf course playing conditions.
A third type of apparatus uses a single screen wound on two
cylinders such that, as it is wrapped around one cylinder, it
unwraps from the other cylinder. If a ball having a side spin is
hit into the screen, it will move the screen laterally in a
direction corresponding to the direction of the spin and in an
amount corresponding to the amount of spin. By detecting the amount
of screen which is unwrapped from one cylinder and wrapped around
the other cylinder, owing to the impact of the spinning golf ball,
the amount of spin and thus the amount of slice or hook can be
determined and indicated. This type of apparatus has the
disadvantage of being expensive and complicated in construction in
that it requires two cylinders and the mechanism associated
therewith for wrapping and unwrapping the screen. Furthermore, the
moving parts in the screen mounting mechanism are subject to wear
and thus to mechanical failure, thus requiring extensive
maintenance.
SUMMARY OF THE INVENTION
It is a primary object of the present invention to provide an
apparatus for detecting the amount of spin imparted to a golf ball
in an indoor golf playing system.
It is another object of this invention to provide an apparatus for
detecting the amount of spin imparted to a golf ball, which
includes an impact surface such as a wall or screen and a row of
detectors positioned between the point from which the golf ball is
hit and the impact surface for detecting the path of the ball as it
is hit towards the surface and after it rebounds from the surface,
thereby detecting and indicating the amount of spin imparted to the
ball.
The present invention is directed to an apparatus for detecting the
amount of spin, e.g., slice or hook imparted to a golf ball in an
indoor golf playing system such as that disclosed in U.S. Pat. No.
3,559,996 which is incorporated herein by a reference. The
apparatus includes an impact surface such as a wall or screen into
which the golf ball is hit. A row of detectors is positioned
between the point from which the ball is hit and the surface. After
the ball has been hit and prior to striking the surface, it crosses
the row of detectors to actuate one or more of them. The ball then
rebounds from the surface and crosses back through the row of
detectors to actuate one or more of them. In the case of a
substantially planar impact surface, if the ball has no spin
imparted to it, the angle of incidence of the ball with respect to
the impact surface will equal the angle of reflection. Thus, when
there is no spin on the ball and it is detected by one or more
detectors as it travels towards the surface, there is a
corresponding known detector or detectors which should be actuated
as the ball rebounds from the surface. If side spin is imparted to
the ball, the actual angle of reflection from the surface will
differ from the angle of reflection when there is no side spin.
Therefore, a ball having side spin will actuate one or more
detectors other than the known detector or detectors which would be
actuated when there is no side spin. By noting which detector (or
detectors) is actuated by the reflected ball having side spin, the
amount of hook or slice can readily be determined and
indicated.
As an illustrative example, one means for detecting the amount of
spin imparted to a golf ball comprises a voltage divider having a
plurality of sections with switches, corresponding to each section,
connected to the detectors. When a golf ball crosses the row of
detectors and actuates one of them, the corresponding switch is
closed, thus setting up a particular voltage divider. The voltage
across the voltage divider, therefore, corresponds to the detector
or detectors actuated by the golf ball. The detecting means also
includes a capacitor for storing the voltage corresponding to the
detector or detectors actuated as the ball travels toward the
impact surface, and another capacitor for storing the voltage
corresponding to the detector or detectors actuated by the
rebounding golf ball. The voltages stored on the two capacitors are
compared so as to produce an output indicative of the amount of
spin imparted to the golf ball.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view showing the angles of reflection for
various angles of incidence of a golf ball, relative to a
substantially planar impact surface, in order to illustrate
generally the principles of the present invention;
FIG. 2 is a schematic plan view showing the positioning of the
impact surface and row of detectors in the apparatus of the present
invention; and
FIG. 3 is a schematic view and circuit diagram of a preferred form
of detecting and indicating means of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIG. 1, if a ball at point 2 is hit into a
substantially planar impact surface 4 such as a wall or screen, the
ball will rebound from the impact surface at an angle determined,
at least in part, by the angle of incidence. If there is no side
spin on the ball, then the angle of reflection from the surface 4
will equal the angle of incidence of the ball onto the surface.
Three paths, A, B and C, are illustrated in FIG. 1. In approach
path A, for example, if there is no spin on the ball, the ball will
be reflected by surface 4 and will follow return path A1. The
angles between approach path A and surface 4, and return path A1
and surface 4, are substantially equal and are designated .alpha..
If, however, the ball has a clockwise side spin or slice imparted
to it, the angle of reflection will be smaller than the angle of
incidence and the golf ball will follow return path A3. If the
clockwise spin or slice is even greater, then the ball will follow
the return path A.sub.3 '. Similarly, if the ball has a
counterclockwise spin or hook imparted to it, then the angle of
incidence will be less than the angle of reflection and the
reflected ball will follow return path A2 shown in FIG. 1. Paths B
and C in FIG. 1 illustrate the effects of hooking and slicing for
different angles of incidence.
FIG. 2 illustrates the incorporation of the side spin detecting
apparatus of the present invention in an indoor golf playing
apparatus such as that disclosed in U.S. Pat. No. 3,559,996. The
golf ball is hit from a known point 6 towards the impact surface 9,
which may be of any suitable construction and preferably is a
substantially planar wall or screen. A row of detectors 10 of any
suitable type is positioned between the point 6 and the impact
surface 9 for detecting the position of the golf ball as it
approaches the surface and as it rebounds from the surface. The
spacing and arrangement of the detectors 10 will depend on the
degree of resolution desired. As an illustrative example, a row of
32 photo detectors 10 may be used, and light sources 12 may be
provided to illuminate the photo detectors 10. The light sources 12
preferably are non-visible, such as infra-red, so that there is no
distraction to the player hitting the golf ball from the point
6.
The photo detectors 10 may be of any suitable type such as photo
diodes, photo transistors, photo multipliers or any other devices
which produce an output signal in response to a change in light
incident on the device. It is to be readily understood, however,
that any suitable type of detection means, other than
light-responsive means, may be utilized within the scope of the
present invention.
In the use of the apparatus of the present invention, as the ball
travels from the point 6 to the surface 9, it crosses the row of
photo detectors 10 and blocks the light from the light sources 12
to one or more of the photo detectors to actuate them, thus
producing a signal at the output of the blocked photo detector or
detectors. In the example shown in FIG. 2, photo detector 16 is
actuated by the ball as it travels toward the impact surface 9.
After striking the surface 9, the ball rebounds therefrom and again
crosses the row of photo detectors 10 to actuate another one (or
more) of the photo detectors by momentarily cutting it off from its
light source 12. If the ball is hit without side spin, the angle of
incidence with respect to a substantially planar surface 9 will
equal the angle of reflection. By knowing the location of the point
6 from which the ball is hit, the location of the point of contact
15 on the surface 9, and the photo detector 16 (or detectors) which
is actuated by the ball travelling from point 6 to point 15, the
photo detector to be actuated by the rebounding ball, if the ball
were hit without side spin, can be predicted. If, however, the
rebounding ball actuates a photo detector or detectors other than
the photo detector 14, this indicates that the ball had side spin
when it hit the point 15 on the surface 9.
As is well known, for a right-handed golfer, when a golf ball is
sliced, the side spin imparted to it is clockwise, and when a golf
ball is hooked, the side spin is counterclockwise. As illustrated
in FIG. 2, if the ball were hooked, its return path might be
represented by the broken line 17, in which event the detector 18
rather than the detector 14 would be actuated by the ball during
its return path. If the ball were sliced, as indicated by the
broken lines 19 or 21, the detector 11 or the detector 8,
respectively, rather than detector 14, would be actuated by the
ball during its return path.
In this manner, it will be readily seen that, by noting the photo
detector or detectors actuated by the ball travelling from the
point 6 from which the ball is hit to the impact point 15 on the
surface 9, and the photo detector or detectors actuated by the
reflected ball, the amount of hook or slice can readily be
determined.
It is noted that the impact surface 9 may be of any suitable
construction and configuration. Although it is preferable that the
impact surface be substantially planar, it may, for example, be
curved or angled so long as it is calibrated to predetermine the
angle of reflection therefrom of a golf ball hit without spin from
a known point of origin. Also, if the golf ball is to be hit from
more than one known point of origin, the impact surface should be
so calibrated for each known point of origin.
In the event the golf ball is to be hit from points of origin that
may not be predetermined, a second row of detectors 110, shown in
broken lines in FIG. 2, may be positioned between the first row of
detectors 10 and the point or points of origin 6. This arrangement
serves to provide an indication of a straight line path defined by
the detectors in each row that are actuated as the ball approaches
the impact surface 9 and as it rebounds therefrom.
As an illustrative example, FIG. 3 illustrates one embodiment of an
apparatus for producing an output indicative of the amount of spin,
e.g., hook or slice imparted to a golf ball, in accordance with the
principles of the present invention. A series of resistors R1
through R32 are connected in series with a source, such as battery
26, and a variable resistor RA. Switches S1 through S32 are
connected between the resistors R1 through R32 and bus 28. Switches
S1 through S32 correspond to the row of 32 photo detectors 10 in
FIG. 2, and are normally open. One or more of the switches S1
through S32 are closed when light incident upon corresponding photo
detectors is blocked by the passage of the golf ball. This may be
accomplished, for example, by means of relays (not shown). A
variable voltage divider is formed by the resistances R1 through
R32 and switches S1 through S32 in combination with battery 26,
such that the configuration of the voltage divider connected to
battery 26 corresponds to the photo detector which is actuated by
the passage of the golf ball.
Switch SA2 associated with relay 30 is normally in the "in"
position as illustrated in FIG. 3. Thus, when the ball is hit and
crosses the row of photo detectors 10, the actuated photo detector
momentarily closes the corresponding switch of the switches S1
through S32 to produce a voltage at terminal 32 indicative of the
closed switch. This voltage is stored on capacitor C1. The blocking
or actuation of any one of the photo detectors 10, as the ball
travels between the point of origin 6 and the impact surface 9,
serves to energize relay 30. This moves switch SA2 to the "out"
position and opens switch SA1, thereby placing variable resistor RA
in the circuit.
As the ball rebounds from the impact surface 9 and again crosses
the row of detectors to actuate another photo detector, this
momentarily closes a different one of the switches S1 through S32
to produce a different voltage at point 32 which is applied to
capacitor C2. Resistor RA is adjusted such that, when the ball is
hit without spin to create an angle of incidence equal to the angle
of reflection relative to a planar impact surface, the voltage
produced at terminal 32, caused by the actuation of one of the
photo detectors during the forward path of the ball, will be the
same as the voltage produced at terminal 32 caused by the actuation
of a second photo detector during the return path of the ball. This
can be accomplished because the angle of incidence equals the angle
of reflection for a ball hit without spin toward a planar impact
surface, and thus the photo detector to be actuated during the
return path can be predicted.
If side spin is imparted to the ball such that it is hooked or
sliced, the voltage stored on capacitor C2 differs from that stored
on capacitor C1, and the two voltages are compared on a comparator
34 which produces an output indicative of the voltage
difference.
The operation of the apparatus of the present invention may be
illustrated by way of an example and by referring to FIGS. 2 and 3.
When a ball is hit from the point of origin 6 and travels to point
15 on impact surface 9, the path of the ball crosses the row of
photo detectors at the location of photo detector 16 in FIG. 2.
This blocks the light incident upon photo detector 16 to produce an
output. The output signal of photo detector 16 closes switch S16
and charges capacitor C1 through amplifier A1, to 16 volts, for
example. Relay 30 is then energized to close switch SA1 and to move
switch SA2 to the "out" position. If the ball is hit without any
side spin, the angle of incidence will equal the angle of
reflection and the reflected ball with block or actuate photo
detector 14. Resistor RA is adjusted such that when switch SA1 is
opened by energization of relay 30 and switch S14 is closed by the
ball blocking light to photo detector 14, the voltage at terminal
30 is 16 volts rather than the 14 volts which would have occurred
if resistor RA had not been put into the circuit. Thus, if the ball
is hit without side spin, capacitor C2 is charged to 16 volts. The
comparison in comparator 34 thus produces a zero output as shown in
FIG. 3.
If, however, the ball were hooked and the path of the reflected
ball blocked or actuated photo detector 18 rather than photo
detector 14, switch R18 would be closed and capacitor C2 would be
charged to 16/14 (18) = 20.6 volts. Comparator 34 thus produces an
output of 4.6 volts to move the pointer 40 to the right an
appropriate amount to indicate the degree of hook. The greater the
counterclockwise side spin or hook, the more to the right the
pointer 40 would move. Similarly, in the case of a clockwise side
spin or slice, the pointer 40 is moved to the left to indicate the
degree of slice. The system then resets for actuation by the golf
ball hit on the next shot.
It is noted that the apparatus of the present invention could be
used to determine and indicate any type of spin imparted to a golf
ball; e.g., spin about a substantially horizontal or vertical axis,
depending on the arrangement of the detectors 10.
* * * * *