Abstract:
A golf club head swing timing device that uses radar to measure the duration of a golf swing. Club head speed measurement is also provided. The details of the disclosed embodiments include the ability of detecting the start and end of a golf swing, and to do so from information from the radar signal. Preferably, RF Doppler radar is used. Various modes of use and display are provided.

Description:
This application is related to commonly assigned and U.S. patent application Ser. No. 10/740,145, filed Dec. 18, 2003, which will issue as U.S. Pat. No. 6,898,971 on May 31, 2005, hereby expressly incorporated by reference herein. 
     U.S. patent application Ser. No. 10/740,145 is a Continuation of U.S. Pat. No. 6,666,089, filed Dec. 3, 2001, which is a Continuation-In-Part of International Application No. PCT/US01/12535, filed Apr. 17, 2001, which claims priority to U.S. Pat. No. 6,378,367, filed Apr. 17, 2000. 
     U.S. Pat. No. 6,378,367 is a Continuation-In-Part of U.S. Pat. No. 6,079,269, filed Jan. 20, 1999, which is a Continuation of U.S. Pat. No. 5,864,061, filed Feb. 5, 1997, all of which are hereby expressly incorporated by reference herein. 
     U.S. Pat. No. 6,378,367 is also a Continuation-In-Part of U.S. patent applications Ser. No. 09/471,905, filed on Dec. 23, 1999 (which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/113,378, filed on Dec. 23, 1998); and Ser. No. 09/471,906, filed on Dec. 23, 1999 (which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/113,434, filed on Dec. 23, 1998) all of which are hereby expressly incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Improvement in the play of golf depends to a large degree on the improvement of the golfers swing. Increased distance in golf shots is known to result from increases in club head speed at the time of impact with the ball. Much effort is devoted to improvement of swing technique with a goal of increasing club head or club swing speed. Instruments have been proposed to measure the swing speed and to thereby assist the golfer by evaluating the results of the efforts to improve swing technique. 
     It has also appreciated that speed of the club head isn&#39;t the only factor of importance in improving a golfer&#39;s swing and improving the golfer&#39;s overall game and golf score. The rhythm of the swing also affects the energy transferred to the ball and the accuracy of the golf shot. Devices for measuring this rhythm have also been proposed. 
     The instruments proposed to assist the golfer in developing a golf swing have suffered from complexity and borne a high cost. This has limited their utility for the average golfer. The instruments proposed have also been difficult to operate, making it inconvenient for the golfer to use without assistance or without interrupting the practice exercise. 
     Accordingly, there remains a need for improved instrumentation in the measurement of swing parameters in the play and practice of golf. 
     SUMMARY OF THE INVENTION 
     In accordance with the principles of the present invention, a radar device has been provided which times the duration of a golf swing. 
     According to certain embodiments of the invention, radar device, preferably a Doppler radar device, is configured to detect club head speed or motion and to use the information derived from the detected motion to time the beginning and end, and hence the duration, of a golf club swing. 
     According to alternative or additional embodiments of the invention, a radar device and method are provided which uses a Doppler radar signal to measure both the speed of a golf club head and the duration of a golf club head swing. 
     These and other objectives and advantages of the present invention will be more readily apparent from the following detailed description of the illustrated embodiments of the invention, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating the set up and use of a golf club swing speed measurement and swing duration timer according to an embodiment of the present invention. 
         FIG. 2  is a diagram illustrating the architecture of an embodiment of the timer of  FIG. 1 . 
         FIG. 3  is a diagram similar to  FIG. 2  illustrating a more specific embodiment to the architecture of the timer of  FIG. 1 . 
         FIG. 4  is a perspective view of an alternative embodiment of the timer of  FIG. 1 . 
         FIG. 5  is a flow chart illustrating one embodiment of the program and operation of the timers of  FIGS. 1-4 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  illustrates the use of a swing speed timer  10  by a golfer  11 , according to certain principles of the present invention. The embodiment of the timer  10  that is illustrated in  FIG. 1  is configured to measure the duration of the swing of a golf club  12 . In certain embodiments, the timer  10  is also configured to measure the peak speed of the club head  13  of the golf club  12 . When the club  12  is swung by the golfer  1 , the peak speed of the club head  13  typically occurs at approximately the moment of impact of the club head  13  with a golf ball  14 , or, in the case of a practice swing without a golf ball  14  present, when the club head  13  passes over the point  15  on a tee  16 , or on the ground at which the golf ball  14  would normally be located. 
     A diagram of an embodiment of the architecture of the timer  10  is illustrated in  FIG. 2 . It includes a transmitter/receiver  20  to which is connected a transmit/receive antenna  21  from which a signal is transmitted and to which a signal is received from a moving object such as the club head  13 . The timer  10  includes a speed signal detector  22  that detects a speed signal from the moving object at an input connected to the transmitter/receiver  20 , a processor  23  that interprets and further processes the speed signal, a timing unit  24 , and an annunciator  25 . 
     When a portion of a transmitted continuous wave signal is reflected from a club head  13  that is moving toward or away from the antenna  21 , the received signal can contain a Doppler shift that is proportional to the frequency of the transmitted signal and the velocity of the club head  13  toward or away from the antenna  21 , as in the timer embodiment  10   a  of  FIG. 3 . In the timer  10   a , detector  22   a , which has an input connected to the transmitter/receiver  20 , detects the amount of the Doppler shift between the transmitted and Doppler-shifted received signals and outputs a Doppler signal to the processor  23 , which may be a microprocessor  23   a . The processor  23   a  derives information from the Doppler signal and correlates it with information from a timing unit  24   a  to measure the duration of the swing of the club  12  by the golfer  11 . The microprocessor  23   a  outputs signals to the annunciator  25 . The processor  23  may also derive the speed of the club head  13  and output it to the annunciator  25 . 
     The transmitter/receiver  20  is one that transmits and receives a signal that is capable of capturing the speed of the club head  13 . Preferably, it transmits and receives a continuous wave signal from which the speed of the club head can be captured by returning a Doppler signal. The continuous wave signal may be an ultrasonic signal, an electromagnetic signal or some other continuous wave signal. In  FIG. 3 , the embodiment of the timer  10   a  that is illustrated has a transmitter/receiver  20   a  that transmits and receives an RF signal, of which C-band and X-band signals are practical examples. 
     The annunciator  25  is one that converts an output signal received over a wired or wireless link from the processor  23  into a form for use or interpretation. In its simplest and most useful form, annunciator  25  converts the outputs into an audible or visual representation perceivable by the golfer  11 . In the embodiment of  FIG. 3 , the annunciator is an LCD display  25   a  on which the swing duration of the club head  13  is displayed to the golfer  11  as a direct and immediate measurement of each swing of the golf club  12  by the golfer  11 . 
     The processor  23  in the embodiment of  FIG. 3  is a microprocessor  23   a  that is capable of interpreting the Doppler signal from the detector  22  to determine whether or not an object, namely the club head  13 , in the field of the antenna  21  is moving, and if so at what speed. The interpretation that the club head  13  is moving is used to determine that the club head  13  is being pulled back from the ball  14  or point  15 , and hence that a swing has begun. This determination is used by the processor  23  to start the timing circuit  24  to time the swing of the club  12 . The interpretation that the club head  13  is moving is also used to validate that the swing is taking place and to distinguish a full swing of the club head  13  from minor motion of the club head  13  or a waggle of the club head  13  as when a golfer  11  is merely addressing the golf ball  14 . This validation can be conducted in a number of ways. One such way can be by integrating the detected motion over a time interval. Such a time interval of, for example 0.05 or 0.10 seconds, during which continuous motion of the club head  13  may be sensed, can be used by the processor  23  to support a determination that a complete swing is taking place. 
     The measurement of the speed of the club head  13  can be used by the processor  23  to determine when the maximum speed of the club head  13  has been reached in a swing, to calculate what the maximum speed of the club head  13  is, and to determine the point in time when the swing of the club  12  has been completed. This end-of-swing determination can be defined as the point of contact between the club head  13  and the ball  14 , and can be taken as the point in the swing at which the speed of the club head  13  is at a maximum. 
     The detection of motion is also useful to the processor  23  in controlling the operation of the timer  10 . This enables the timer  10  to be operated by a golfer  11  or other user in a hands-off manner. For example, one embodiment of timer  10  can be operated by merely turning it on. Then, the sensing of motion of the club head  13  can be used to operate the timing unit  24  by starting a time measurement at the beginning of a swing and stopping the measurement of the swing duration at the end of a swing. The processor  23  can also determine when to enable and disable the timer  10 , when to measure the speed of the club head  13 , and when and how to operate the display  25   a  or other annunciator  25 . 
     In  FIG. 1 , timer  10   a  is illustrated in a plastic housing  30  having a three digit LCD display  25   a  mounted therein and one or more user interface buttons, which, in this embodiment, include a single momentary push-button  31  on the front of the housing  30 . A support leg  32  is provided on the housing  30  to allow it to be set on the ground. Within the housing  30  are battery operated components that include the transmitter/receiver  20 , the antenna  21 , the detector  22 , the processor  23  and the timer  24 . These components may be configured according to the principles set forth in detail in the related patents and applications that are identified at the beginning of this application and have been incorporated by reference herein. The display  25   a  and push button  32  are connected to the processor  23 . 
     The use and operation of the timer  10  can be considered with reference to  FIG. 1 , where the golfer  11  can set the compact housing  30  of the timer  20  on the ground adjacent a point  15  at which a golf ball  14  or tee  16  may be located during the practice of a golf swing. The housing  30  is shown placed even with the point  15 , eight to ten inches on the opposite side thereof from the golfer  11 , and facing parallel or at a slight angle, preferably less than forty-five degrees, to the path of the club head  13  of the golf club  12 , pointing generally toward the face of the approaching club head  13  during a swing. In this location, the timer  10  can be used to measure a golf swing when the golfer  11  is actually hitting golf balls. 
     Alternatively, the timer  10  can be placed directly behind the ball  14  or point  15 , facing forward in the direction of the motion of the club head  13 , close to the ball but sufficiently behind the ball to avoid being hit by the club head  13 . As long as the transmitted power is low and the timer  10  sensitivity is carefully limited, the timer  10  can measure club head motion from this position without substantial errors due to a detecting of the motion of the golf ball. The timer  10  can also be similarly placed in front of the ball, facing the approaching club head  13 , provided that no actual golf ball or other hard object is being hit. Placed in front, the timer  10  is susceptible to being hit by the golf ball which can injure the golfer  11  or damage the timer  10 . 
     A further embodiment of the timer  10  is illustrated in  FIG. 4 , which shows timer  10   b  in a housing  30   b  shaped to protect the timer  10   b  from being hit by a golf ball  14  so that the timer  10   b  can be used to measure the speed of the golf ball  14  being hit by the golfer. In this embodiment, the housing  30   b  is shaped to deflect a ball if one were to hit the housing  30   b  without bounding it back toward the golfer  11 . The antenna  21  of the unit can be aimed toward the point  15  to measure the speed of the ball  14  leaving the tee. In this case, the swing speed can also be measured as described above. However, distinguishing club head motion and ball motion could require careful adjustment and placement to avoid erroneous measurement results. This can be avoided, particularly when measuring only the speed of a ball hit from a low-angled club head, by orienting the timer  10   b  so that the antenna  21  faces away from the tee toward the path of the ball. 
     While  FIG. 4  shows the antenna  21  facing away from the tee toward the path of the ball, which would be away from the tee, toward the fairway, or the direction that the ball is traveling toward, the ball speed can either be measured with the radar antenna looking back at the ball coming off of the tee, or after the ball has traveled over the radar antenna and is moving away from it. 
     Alternatively, the radar antenna can be located forward of the ball, for example approximately two to three feet from the tee where it can also read the speed of the club head. The reflected signal will contain two Doppler components, one representing the speed of the club head and one representing the speed of the ball. The club head speed will be at one speed, for example 150 mph, while the ball speed might be about 30% to 50% faster than the ball speed. The two speeds can be distinguished by an appropriately configured detector and processor. Either the output of the club head speed and that of the ball speed may be output by the annunciator. Alternatively, the separate club head and ball speed readings can be toggled or alternated to display both club head and ball speed, or sent to a remote annunciator for output or to a compute for recording or analysis. 
     With the radar antenna on the ground in front of the tee, the ball speed is best detected when the ball is launched from the tee or other surface at a relatively shallow angle, for example, less than 12 degrees. This occurs when balls are hit by low angled woods such as drivers, rather than irons or lofted woods. 
     With any of the embodiments of the above, particularly the timer  10   b  of  FIG. 4 , the annunciator  25  can be an annunciator  25   b  located remote from the transmitter/receiver  20  or at least the antenna  21 . Communication of information can include a wired or wireless link between the locations of the antenna  21  and annunciator  25 . The wireless link, if used, can be placed between two components of the system or in more than one location. A wireless link between the processor and annunciator is a practical arrangement. Locating the wireless link between the transmitter and detector or between the detector and processor are also useful configurations. The annunciator  25  can be in the form of a computer or other data processing unit or output device. 
     The use and operation of the timer  10  can be understood by reference to a sample flowchart as set forth in  FIG. 5  in the description of which the boxes are referenced in parenthesis. 
     When placing the timer  10   a  as described above in connection with  FIG. 1 , the golfer  11  need only press ( 50 ) the button  31  to turn the timer  10   a  “on”. A “ready” indicator  33  is provided on the display  25   a  to indicate that the timer  10   a  is enabled and ready to detect and measure a swing. As the unit powers up, the “ready” indicator turns on ( 52 ), the timer  24  is reset to zero ( 60 ) and proceeds to measure time from that point. When the “ready” indicator  33  is on ( 70 ), if no motion is detected ( 54 ) by the timer  10   a  within a timeout interval ( 56 ), of for example 5 minutes, the timer  10   a  is programmed to turn itself off ( 58 ). If any motion is detected ( 54 ) during this interval ( 56 ), the processor proceeds to interpret the signal. 
     At this point in time, the timer  10   a  is looking for motion in the form of a pullback of the club head  13  from the point  15 , where the ball  14  would be located. If, when the timer is on and in the “ready” condition ( 62 ), any motion that is detected ( 54 ) within the field of the antenna  21  will be processed as a possible beginning of a swing. Therefore, when any Doppler signal is detected by the detector  22 , the timing unit  24  is started ( 64 ) and the “ready” indicator is turned off ( 66 ). But since not every detected Doppler signal is necessarily indicative of the beginning of an actual swing, the detection of an actual swing must be validated ( 68 ). This validation is accomplished by analysis by the processor  23  of the output of the detector  22 . In the described embodiment, the analysis involves determining the presence of a continuous speed signal, namely the continuous presence of a Doppler signal, for a time interval long enough to be the result of the beginning of an actual swing. Therefore, the processor  23   a  continues to test ( 68 ) for the presence of a Doppler signal for a period of 50 or 100 milliseconds, which is likely to be produced by the pullback of a club head  13  for one or two feet, and not produced by other motion of the club head  13 , such as occurs when a golfer merely waggles the club head  13  in addressing the ball, or the golfer terminates the swing. 
     If, after motion is sensed ( 54 ), motion stops ( 54 ) before the validation interval has expired ( 68 ), a false start is detected. In the case of a false start, after waiting an interval ( 74 ) that is longer than that needed for a valid swing, the timing unit  24  is reset ( 60 ) and the “ready” indicator  34  is turned back on ( 52 ). In the example of  FIG. 5 , the resetting waits 4 seconds before a new swing can start. 
     If the sensed pullback of a club head is validated ( 68 ) as an actual swing by sensing the presence of a club head speed signal for the required minimum amount of time, the processor  23  ignores ( 80 ) any detected speed signal within a time interval after the start of the timer unit  24  that is less than the shortest possible swing. In the example, that is taken to be one-half second. After this minimum swing time interval ( 80 ) elapses from the sensed start of the swing ( 64 ), assuming the swing is validated as a probable full swing ( 68 ), the processor  23   a  stores a value for the maximum swing speed, initially at zero ( 82 ), then continues to measure the speed of any sensed motion ( 84 ) for a given period of time ( 86 ) that is longer than the longest anticipated swing duration, which is chosen as four seconds in the illustrated example. During this period, the stored value for maximum speed is replaced ( 88 ) by any measured speed that is greater than the previously stored speed. Further, whenever new maximum speed is stored ( 88 ), the value of the timer  24  is also stored ( 90 ). At the end of the given speed measurement ( 86 ), the values of maximum sensed club head speed ( 92 ) and swing duration ( 94 ) will be stored in memory to be output to the annunciator  25 . The output swing duration ( 94 ) will be the length of time from when the club head pullback was first sensed ( 64 ) until the maximum club head speed was measured ( 88 ), which typically occurs at the point  15  at which the club head contacts the ball  14 . 
     When a display  25   a  is the annunciator  25 , numerical values for swing speed and swing duration are displayed according to the display mode selected. If two consecutive numbers to be displayed are the same ( 96 ), the display is made to switch ( 98 ) from a steady display to a flashing display so that the golfer  11  or other user knows that there has been a reading taken that is unchanged in value. When consecutive measurements differ, the values are displayed as steady readings ( 100 ). The mode of operation can be selected by the user to measure either only swing speed ( 102 ), only swing duration ( 104 ), or both ( 106 ). When both swing speed and swing timing are to be displayed, they are displayed alternately on the three digit LCD screen of the display  25   a.    
     When new measured values have been displayed, the timer  24  returns ( 110 ) to the beginning of the program to await another swing. The timer  24  is reset to zero ( 60 ), the “ready” indicator  34  is turned on ( 52 ), and the timer  10   a  proceeds to the sensing of the motion ( 54 ) of the next swing to be measured. If no such motion is sensed within the maximum time-out interval ( 56 ), the timer  10  turns itself off ( 58 ). Alternatively, the timer  10  can be turned off manually by pressing the on/off button  31  when the timer is on. 
     Other applications of the invention can be made. Those skilled in the art will appreciate that the applications of the present invention herein are varied, and that the invention is described in preferred embodiments. Accordingly, additions and modifications can be made without departing from the principles of the invention. Accordingly, the following is claimed: