Flex meter for sports game implements

• US 5,796,005 A
• Filed: 12/06/1993
• Issued: 08/18/1998
• Est. Priority Date: 06/12/1991
• Status: Expired due to Term

• Current Assignee: Jack L. Frolow
• Original Assignee: Jack L. Frolow
• Inventors: Frolow, Jack L.
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US08/161,975
• Time in Patent Office: 1,716 Days
• Field of Search: 73/651, 73/579, 73/862.41, 73/12.01, 73/12.04, 73/65.03, 73/862.43, 73/514.26, 73/514, 73/35, 73/514.36, 73/493, 273/72 R, 273/73 R, 273/77 A, 273/80 B, 200/61.51, 200/61.45 R, 340/683, 473/223, 473/461
• US Class Current: 73/651
• CPC Class Codes: G01H 1/06 Frequency
• CPC Class Codes: G01H 5/00 Measuring propagation velocity of ultrasonic, sonic or infrasonic waves , e.g. of pressure waves

Abstract

A combination of an implement employed in a sports game to impact with a body, and a device coupled to the implement which measures the natural frequency and the relative amplitude of vibration of the implement resulting from the impact. The implement can be a game racket, bat, club or the like and the body impacted can be a ball. The lower the value of the natural frequency of vibration of the implement the more flexible the implement is when it impacts the ball, the greater is the amplitude of the vibration of the implement and the rebound of the ball has a lower velocity. One of the embodiments, called a FLEX METER is a frequency measuring device which employs a series of reeds mounted on a base member each reed being adjusted to vibrate at a maximum amplitude when a vibration having a designated frequency is applied to the base member. Each reed is identified with a designated frequency. A light emitting diode associated with each reed emits light when a reed responsive to the vibration of the implement has an amplitude sufficient to make an electrical connection to a closely positioned contact. The devices are all small in weight, size and are portable and convenient to use with the implement.

Claims

1. A combination for measuring the flexing of an implement said implement being a second body employed by a player in a sports game to have an impact with a first body, a single said impact being for a short interval of time, said implement responsive to a single impact having a mode of natural vibratory flexing in said implement, said mode of natural vibratory flexing having a natural frequency having an unknown value f_r and an amplitude having a value A_x at a location x on said implement;

said combination comprising a measuring means measuring said implement subsequent to said impact, providing a measured value indicating said value f_r, said measuring means comprising at least one mechanical element having a known natural frequency of vibration;

said natural frequency being substantially the same as said frequency f_r ;

a coupling means coupling said measuring means to said mode of natural vibratory flexing, the amplitude and natural frequency of vibration of said mechanical element indicating said value f_r and thereby the vibratory flexing of said implement, a higher said value f_r indicating said natural vibratory flexing having an amplitude having a value A_x being lesser.

2. A combination as in claim 1, wherein said implement is a game racket.

3. A combination as in claim 1, wherein said implement is a bat.

4. A combination as in claim 1, wherein said implement is a club.

5. A combination as in claim 1, wherein said implement has locations not moving during said vibration, said locations being defined as nodal locations, and wherein said measuring means having coupling to said implement at a position close to one of said nodal locations, thereby providing that the said value fr is changed a minimal amount by said measuring means having said coupling.

6. A combination as in claim 1, wherein said measuring means comprises a single reed having a first end, a second end and a length between said ends;

said first end having a mounting in a base member, said mounting providing for the adjustment of the extended length of said reed from said base member, said extended length being adjusted to obtain the maximum amplitude of vibration of said reed responsive to said mode of vibratory flexing of said implement being coupled to said base member;

said base member having markings, said markings indicating said frequency fr, associated with said adjusted extended length of said reed.

7. A combination as in claim 6, wherein the shape of said reed in a plane perpendicular to the direction of the vibration of said reed is substantially triangular having the base portion of the triangular shape mounted in said base member.

8. A combination as in claim 1, wherein said coupling means provides for quickly coupling and quickly decoupling said measuring means to said vibratory flexing.

9. A combination as in claim 1 having a contactor means for making an electrical connection upon contact of said mechanical element with said contactor means said contactor means being positioned close to said mechanical element;

said mechanical element responsive to said coupling to said mode of natural flexing having an amplitude of vibration sufficient to make contact with said contactor means for making said electrical connection;

a light source;

means for said light source to emit observable light indicating said mechanical element having said amplitude and said natural frequency of vibration indicating said value fr.

10. A combination as in claim 9 wherein said light source is a light emitting diode.

11. A combination as in claim 9 wherein said means for said light source includes a power source being integral with said measuring means.

12. A combination as in claim 9 wherein said mechanical element being electrically conductive.

15. A combination as in claim 4, wherein said coupling means provides for said reeds to vibrate in a direction toward the adjacent said spaced reeds.

13. A combination for measuring the flexing of an implement said implement being a second body employed in a sports game by a player to impact with a first body, a single said impact occurring at a location on said implement and being a force having a short duration of time;

said implement responsive to a single said impact to have a natural mode of vibratory flexing between a first extreme position and a second extreme position a number of cycles in a period of time, said implement having a longitudinal axis, said axis being flexed into a first curve in said first position and into a second curve in said second position, said second curve being opposite to said first curve, said number being defined as a natural frequency of said natural mode of vibratory flexing of said implement having an unknown value of f_r in cycles per second;

at a location X on said longitudinal axis, one half the distance between said first position and said second position being defined as the amplitude of said mode of vibratory flexing at said location X having the value A_x ;

said implement having an effective mass M_e at the said location of the impact, said effective mass M_e being defined in the expression ##EQU9## M₁ being the mass of said first body, ν

₁ being the velocity of said mass M₁ just prior to said impact, ν

₁ '"'"' being the velocity of said mass M₁ just subsequent to said impact, ν

₂ being the velocity of the point on said implement being impacted just prior to said impact and being zero, ν

₂ '"'"' being the velocity of said point on said implement being impacted just subsequent to said impact;

said combination comprising a measuring means measuring said implement subsequent to said impact, providing a measured value indicating said frequency f_r, said measuring means comprising at least one mechanical element having a known natural frequency of vibration, said natural frequency being substantially the same as said frequency f_r ;

coupling means coupling the said measuring means to said natural mode of vibratory flexing, the amplitude and natural frequency of said mechanical element indicating said value f_r and thereby the flexing of said implement, a higher value of said frequency f_r indicating a smaller said value of said mode of vibratory flexing having the value A_x, a greater said effective mass M_e, and a greater said rebound velocity ν

₁ '"'"'.

14. A combination as in claim 13, wherein said measuring means comprises a plurality of spaced reeds secured in a base member, said reeds having their length and weight adjusted to provide each reed vibration be a maximum amplitude responsive to a vibration having a designated frequency and amplitude being applied to said base member;

identifying means for identifying each of said reeds with said designated frequency, said designated frequency being designated in a series of values.

16. A combination as in claim 14 wherein said reeds have a weight attached to a portion of the reed length at a position distal to said base member.

17. A combination as in claim 16 wherein said weight being slidably attached to said portion of the reed length said position being capable of being adjusted to obtain a maximum amplitude of vibration of said reed responsive to said vibration having said designated frequency being applied to said base member.

18. A combination as in claim 14, wherein at least one reed being coated with a color, said color being repeated in said identifying means identifying said designated frequency associated with each reed.

19. A combination as in claim 14, wherein said measuring means is enclosed in a protective case having the portion of said case adjacent to the distal ends of said reeds from said base member being an optical magnifier in only one direction of the vibratory motion of said reeds, thereby providing for the amplitude of vibration of said reeds to be easily observed.

20. A vibrometer for measuring the frequency of vibration of a vibrating body having a frequency of vibration having an unknown value f_r, said vibrometer comprising;

a plurality of mechanical elements, said elements being mounted on a supporting member, each of said mechanical elements having a natural frequency of vibration, the said natural frequencies of vibration of said plurality of mechanical elements having known predetermined different values, said values progressing in substantially uniform incremental steps from a first limit of lower value to a second limit of higher value;

at least one mechanical element of said plurality of mechanical elements having a known natural frequency of vibration, said natural frequency having substantially the said value f_r ;

each of said plurality of mechanical elements having a contactor being mounted close to said mechanical element on said supporting member, said contactor being capable of making an electrical connection upon contact of said mechanical element with said contactor;

said mechanical element having a natural frequency of vibration having a value of substantially the said value f_r, responsive to said supporting member being mechanically coupled to said vibrating body, having sufficient amplitude of vibration to contact said contactor;

a plurality of light sources, said light sources being mounted on said supporting member, each of said light sources being separately connected electrically to each of said contactors;

each of said light sources being capable of emitting observable light responsive to said mechanical element having sufficient amplitude of vibration to contact said contactor and indicating said value f_r.

21. A combination as in claim 20 wherein said light source is a light emitting diode.

22. A combination as in claim 20 wherein said means for said light source to emit observable light includes a power source integral with said vibrometer.

23. A combination for measuring the spring constant having a value of T of the string netting plane of a game racket, comprising a measuring means measuring the frequency of the vibration of said netting plane responsive to a single impact, said measuring means having a weight having a value of W_v ;

said string netting plane having said measuring means fastened to said string netting plane, responsive to a single impact having a vibration having a frequency having an unknown value of f_s said measuring means responsive to said single impact indicating said value f_s, thereby indicating said value T, said value T being determined by said value W_v, and said value f_s ;

said measuring means being at least one mechanical element having a known natural frequency of vibration, said natural frequency being substantially the same as said frequency f_s, the amplitude and said natural frequency of said mechanical element responsive to said single impact indicating said value f_s.

24. A combination as in claim 23 wherein said measuring means being a plurality of spaced reeds secured in a base member, said reeds having their length and weight adjusted to provide each reed vibration be a maximum amplitude responsive to a vibration having a designated frequency and amplitude being applied to said base member;

identifying means for designating each of said reeds with said designated frequency, said designated frequency being designated in a series of values, at least one spaced reed having an amplitude of vibration responsive to said single impact, indicating a value substantially close to said value f_s.

25. A combination as in claim 23 wherein said measuring means being a single reed having a first end, a second end and a length between said ends;

said first end having a mounting in a base member, said mounting providing for the adjustment of the extended length of said reed from said base member, said extended length being adjusted to obtain the maximum amplitude of vibration of said reed responsive to said vibration of said netting plane;

said base member having markings, said markings indicating said value f_s associated with said adjusted extended length of said reed.

26. A vibrometer for measuring the frequency of vibration of a vibrating body having a frequency of vibration having an unknown value f_r, said vibrometer comprising;

a plurality of mechanical elements, said elements being mounted on a supporting member, each of said mechanical elements having a natural frequency of vibration, the said natural frequencies of vibration of said plurality of mechanical elements having known predetermined different values, said values progressing in substantially uniform incremental steps from a first limit of lower value to a second limit of higher value;

at least one mechanical element of said plurality of mechanical elements having a known natural frequency of vibration, said natural frequency having substantially the said value f_r ;

each of said plurality of mechanical elements having a contactor being mounted close to said mechanical element on said supporting member, said contactor being capable of making an electrical connection upon contact of said mechanical element with said contactor;

said mechanical element having a natural frequency of vibration having a value of substantially the said value f_r, responsive to said supporting member being mechanically coupled to said vibrating body, having sufficient amplitude of vibration to contact said contactor;

a plurality of light sources, said light sources being mounted on said supporting member, each of said light sources having separate wiring to each of said contactors;

said wiring providing pulses of electrical current upon said contact of said mechanical element with said contactor, said pulses of current not being encoded;

each of said light sources emitting observable light responsive to said pulses of current being responsive to said mechanical element having sufficient amplitude of vibration to contact said contactor and thereby indicate said value f_r .