Matched set of golf clubs and method of producing the same

• US 5,879,241 A
• Filed: 03/04/1997
• Issued: 03/09/1999
• Est. Priority Date: 03/04/1997
• Status: Expired due to Term

• Current Assignee: Michael Atkinson
• Original Assignee: Eric H. Cook, Michael A. Atkinson
• Inventors: Atkinson, Michael A., Cook, Eric H.
• Primary Examiner(s): Passaniti, Sebastiano
• Assistant Examiner(s): BLAU, STEPHEN LUTHER
• Application Number:
  US08/811,371
• Time in Patent Office: 735 Days
• Field of Search: 473/287, 473/289, 473/290, 473/291, 473/292, 473/409, 473/297
• US Class Current: 473/289
• CPC Class Codes: A63B 53/00 Golf clubs
• CPC Class Codes: A63B 53/005 Club sets
• CPC Class Codes: A63B 60/42 Devices for measuring, verifying, correcting or customising the inherent characteristics of golf clubs, bats, rackets or the like, e.g. measuring the maximum torque a batting shaft can withstand

Abstract

The present invention provides a matched set of golf clubs, wherein each club in a set of golf clubs, irons, woods, or a combination thereof, provides the golfer with precisely the same feel, related to the golfer'"'"'s swing when the club is swung, and to the contact between the head of the club and golf ball when the ball is hit. In the present invention the clubs are matched dynamically. The clubs will have one or all of the following characteristics: (1) a constant flexural rigidity of each complete iron and/or each complete wood, (2) a constant moment of inertia, and (3) a the center of gravity which is calculated by using a constant force for the shortest club in the set.

Claims

1. A correlated set of golf clubs for use by a golfer, said correlated set of golf clubs comprising:

at least two golf clubs of an equivalent set;

each club includes a shaft having a first end and a butt end;

a head being located at said first end and a grip being located at said butt end;

said head having a head weight;

said plurality of shafts lengths decreases as said head weights increases;

each club has a measured frequency when said head is attached thereto and said measured frequency is established by tip cutting said first end of said shaft, until re-measured frequency equal the established required frequency for the club set being built;

said measured frequency of said plurality of clubs being within plus or minus 1 cycle per minute of said established frequency;

said set of golf clubs includes a base club, said base club is a completed club and includes a first length, said first length is the shortest length in said set of golf clubs, a force (F) is calculated for said base club using the following equation;

##EQU5## wherein;

C is a measured distance from the center of gravity of said base club to said butt end of said club;

W is a total weight of said head and said shaft of said base club;

L₁ is said first length plus d₂ for d₂ being a point above said butt end of said grip of said base club used as the axis of rotation;

a center of gravity is calculated for each additional club of said set using the following equation;

##EQU6## C_n is a calculated measurement establishing a location of said center of gravity of club n measured from said butt end of said grip of club n;

W_n is a total weight of said head and said shaft of said club n; and

L_n is a length of said club n plus d₂ for d₂ being a point above said butt end of said grip of said club n used as the axis of rotation.

2. A correlated set of golf clubs as in claim 1, wherein each club has a swing weight which produces an optimum hit, said swing weight represents a moment of inertia (MI), each of said shafts includes said head weight (M_h), each of said club includes a playing length (L), each of said shafts includes a weight (M_s), each butt end includes a weight (M_b), and said head weight (M_h) being represented by:

##EQU7## for d₁ being a distance from a center of said butt weight to said butt end of said grip and d₂ being a point above said butt end of club used as the axis of rotation.

3. A correlated set of golf clubs as in claim 2 wherein d₁ and d₂ are equal to 2 inches.

4. A correlated set of golf clubs as in claim 1, wherein said club has a moment of inertia and said moment of inertia is substantially constant for each club and is related to the club head speed generated by the golfer.

5. A correlated set of golf clubs as in claim 4, wherein said moment of inertia (MI) is a swing weight, said swing weight is directly related to a club head speed for providing an optimum performance, each of said clubs includes a playing length (L), each of said shafts includes a weight (M_s), each butt end includes a weight (M_b), and said head weight (M_h) being represented by the following calculation:

##EQU8## for d₁ being a distance from a center of said butt weight to said butt end of said grip and d₂ being a point above said butt end of club used as the axis of rotation.

6. A correlated set of golf clubs as in claim 5, wherein d₂ is equal to 2 inches.

7. A correlated set of golf clubs as in claim 1, wherein d₁ and d₂ are equal to 2 inches.

8. A method of designing a correlated set of golf clubs for use by a golfer, wherein each club has a same feel, each golf club in the set has a different length and includes a shaft having a butt end and a first end, and said first end has a head and said butt end includes a grip, said method comprising:

(a) establishing a required frequency for an assembled golf club by tip cutting a first end of a shaft of each club; and

(b) providing said frequency of said clubs to be within plus or minus 1 cycle per minute of each other when said club is assembled;

(c) adjusting said assembled frequency to equal said frequency via tip cutting, reattaching said head to said shaft, and re-measuring said assembled club, re-adjusting said length and re-measuring said assembled frequency until said assembled frequency is equal to said recorded selected frequency.

9. A method as in claim 8 wherein there is provided the further step of correlating each club to have a substantially constant moment of inertia.

10. A method as in claim 9 wherein there is provided the further step of calculating a center of gravity which is inversely proportional to a swing force of a golfer, and said center of gravity for each club includes a constant force.

11. A method as in claim 8 wherein there is provided the further steps of:

(c) providing a grip on said butt end and establishing a swing weight which produces an optimum hit and said swing weight represents a moment of inertia (MI);

(d) calculating a head weight (M_hn) for each club by the equation;

##EQU9## where, L_n is a playing length of club n,

M_sn is a shaft weight of club n,

M_bn is a weight for a butt end of club n,

L_sn is a length of a shaft of club n,

for d₁ being a distance from a center of said butt weight to said butt end of said grip and d₂ being a point above said butt end of club n used as the axis of rotation.

12. A method as in claim 11 wherein d₁ and d₂ are equal to 2 inches.

13. A method as in claim 11 wherein there is provided the further steps of:

(e) establishing a base club, said base club includes a first length, said first length is the shortest length in said set of golf clubs

(f) calculating a force (F) for said base club using the following equation;

##EQU10## wherein;

C is a measured distance from a center of gravity of said base club to said butt end of said club;

W is a total weight of said head and said shaft of said base club;

L₁ is said first length plus d₂ for d₂ being a point above said butt end of said grip of said base club used as the axis of rotation;

(g) calculating a center of gravity for each additional club of said set using the following equation;

##EQU11## wherein C_n is a calculated measurement establishing a distance from said butt end from club n of said set to said center of gravity of club n;

W_n is a total weight of said head and said shaft of said club n; and

L_n is a length of said club n plus d₂ for d₂ being a point above said butt end of said grip of said club n used as the axis of rotation.

14. A method as in claim 8 wherein there is provided the further steps of:

(d) selecting a base club, said base club includes a first length;

(e) calculating a force (F) for said base club using the following equation;

##EQU12## wherein;

C is a measured distance from a center of gravity of said base club to said butt end of said club;

W is a total weight of said head and said shaft of said base club;

L₁ is said first length plus d₂ for d₂ being a point above said butt end of said grip of said base club used as the axis of rotation;

(f) calculating a center of gravity for each additional club of said set using the following equation;

##EQU13## wherein C_n is a calculated measurement establishing a location of said center of gravity of club n measured from said butt end of said grip of club n;

W_n is a total weight of said head and said shaft of said club n; and

L_n is a length of said club n plus d₂ for d₂ being a point above said butt end of said grip of said club n used as the axis of rotation.

15. A method of matching a correlated set of golf clubs to a particular golfer, wherein each club has a same feel for said particular golfer, each golf club in the set has a different length and includes a shaft having a butt end and a head end, and said head end has a head, said method comprising:

(a) finding a club of the best accuracy, distance, and trajectory from a set of preset test clubs for determining a proper flexural rigidity;

(b) recording a frequency from said best felt club;

(c) establishing a best swing weight;

(d) recording said swing weight for conversion to a moment of inertia;

(e) calculating a head weight (M_hn) using said moment of inertia MI for each club by the equation;

##EQU14## where, L_n is a playing length of club n,

M_sn is a shaft weight of club n,

M_bn is a weight, including said grip added to said shaft for a butt end of club n,

L_sn is a length of a shaft of club n,

for d₁ being a distance from a center of said butt weight to said butt end of said grip and d₂ being a point above said butt end of said club n used as the axis of rotation;

(f) assembling each club by attaching a head to a first end of a shaft and measuring an assembled frequency;

and

(g) adjusting said assembled frequency to equal said frequency via tip cutting, reattaching said head to said shaft, and re-measuring said assembled club, re-adjusting said length and re-measuring said assembled frequency until said assembled frequency is equal to said recorded selected frequency.

16. A method as in claim 15 wherein there is provided the further steps of:

(h) selecting a base club, said base club includes a first length;

(i) calculating a force (F) for said base club using the following equation;

##EQU15## wherein;

C is a measured distance from a center of gravity of said base club to said butt end of said base club;

W is a total weight of said head and said shaft of said base club;

L₁ is said first length plus d₂ for d₂ being a point above said butt end of said grip of said base club used as the axis of rotation;

(j) calculating a center of gravity for each additional club of said set using the following equation;

##EQU16## wherein C_n is a calculated measurement establishing a distance from said butt end of club n of said set to said center of gravity of club n;

W_n is a total weight of said head and said shaft of said club n; and

L_n is a length of said club n plus d₂ for d₂ being a point above said butt end of said grip of said club n used as the axis of rotation.

17. A method as in claim 16 wherein d₁ and d₂ are equal to 2 inches.