Golf club

• US 6,196,935 B1
• Filed: 04/09/1998
• Issued: 03/06/2001
• Est. Priority Date: 09/29/1995
• Status: Expired due to Term

• Current Assignee: Cymer Incorporated (ASML Holding NV)
• Original Assignee: Active Control eXperts, Inc. (ASML Holding NV)
• Inventors: Jacques, Robert N., Gilbert, David, Bianchini, Emanuele, Spangler, Ronald, Moore, Jeffrey W., Lazarus, Kenneth B., Allen, Jonathan C., Russo, Farla M., Prestia, Carl
• Primary Examiner(s): Chapman, Jeanette
• Assistant Examiner(s): BLAU, STEPHEN LUTHER
• Application Number:
  US09/057,972
• Time in Patent Office: 1,062 Days
• Field of Search: 473/318, 473/564, 473/558, 473/521, 310/317, 310/326, 280/602
• US Class Current: 473/318
• CPC Class Codes: A63B 53/00 Golf clubs
• CPC Class Codes: A63B 60/00 Details or accessories of golf clubs, bats, rackets or the like
• CPC Class Codes: A63B 60/54 with means for damping vibrations
• CPC Class Codes: A63C 5/075 Vibration dampers vibration dampers per se F16F7/00

Abstract

A golf club includes an electroactive assembly attached to the club and electrically tuned to capture energy from one or more vibrational modes with high efficiency. More generally, a sports implement includes an electroactive element, such as a piezoceramic sheet attached to the implement, and a circuit attached to the electroactive element. The circuit may be a shunt, or may include processing such as amplification and phase control to apply a driving signal which may compensate for strain sensed in the implement, or may simply alter the stiffness to affect performance. The electroactive element is located in a region of high strain to apply damping, and may include plural subassemblies mounted to capture energy in different planes, or to capture an asymmetric strain distribution while maintaining structural symmetry. In a ski the element captures between about one and five percent of the strain energy of the ski. The region of high strain may be found by modeling mechanics of the sports implement, or may be located by empirically mapping the strain distribution which occurs during use of the implement. In other embodiments, the electroactive elements may remove resonances, adapt performance to different situations, or enhance handling or comfort of the implement. Other embodiments include striking implements intended to hit a ball or object in play, such as mallets, bats and tennis racquets, wherein the strain elements may alter the performance, feel or comfort of the implement. The electroactive elements may be configured in sets to capture energy in different modes, and/or energy distributed along different directions.

Claims

1. A golf club, comprising:

a body having an extent and a contact surface which is subject to stimulation such that at least a portion of the body vibrates with a distribution of strain energy that includes a region of strain; and

an electroactive assembly comprising;

an electroactive strain element for transducing electrical energy and mechanical strain energy; and

a circuit across said assembly configured to dissipate said electrical energy and damp vibration of the body,

wherein said electroactive assembly is attached to said body in said region of strain such that said electroactive assembly is attached on a shaft and away from the contact surface.

2. A golf club according to claim 1, wherein said electroactive assembly is attached to a flat, raised surface, a face of the head or a feature of the club effective to couple strain out of the club.

3. A golf club, comprising:

a body having an extent and a contact surface which is subject to stimulation such that at least a portion of the body vibrates with a distribution of strain energy that includes a region of strain; and

an electroactive assembly comprising;

an electroactive strain element for transducing electrical energy and mechanical strain energy; and

a circuit across said assembly configured to dissipate said electrical energy and damp vibration of the body,

wherein said electroactive assembly is attached to said body in said region of strain, and

wherein the electroactive assembly further comprises plural regions of separately-electroded piezo material, the separate regions being configured to damp vibration in different planes.

4. A golf club, comprising:

a body having an extent and a contact surface which is subject to stimulation such that at least a portion of the body vibrates with a distribution of strain energy that includes a region of strain; and

an electroactive assembly comprising;

an electroactive strain element for transducing electrical energy and mechanical strain energy; and

a circuit across said assembly configured to dissipate said electrical energy and damp vibration of the body,

wherein said electroactive assembly is attached to said body in said region of strain, and

wherein said circuit is an inductive shunt for dissipating charge generated by strain coupled from said region of strain into said element.

5. A golf club, comprising:

a body having an extent and a contact surface which is subject to stimulation such that at least a portion of the body vibrates with a distribution of strain energy that includes a region of strain; and

an electroactive assembly comprising;

an electroactive strain element for transducing electrical energy and mechanical strain energy; and

a circuit across said assembly configured to dissipate said electrical energy and damp vibration of the body,

wherein said electroactive assembly is attached to said body in said region of strain, and

wherein said strain element is embedded in a shaft formed of composite material.

6. A golf club, comprising:

a body having an extent and a contact surface which is subject to stimulation such that at least a portion of the body vibrates with a distribution of strain energy that includes a region of strain; and

an electroactive assembly comprising;

an electroactive strain element for transducing electrical energy and mechanical strain energy; and

a circuit across said assembly configured to dissipate said electrical energy and damp vibration of the body,

wherein said electroactive assembly is attached to said body in said region of strain, and

wherein said electroactive assembly is a flexible, curved assembly fitted to the club and formed as a sheet with relief cuts for conforming to the club.

7. A golf club, comprising:

a body having an extent and a contact surface which is subject to stimulation such that at least a portion of the body vibrates with a distribution of strain energy that includes a region of strain; and

an electroactive assembly comprising;

an electroactive strain element for transducing electrical energy and mechanical strain energy; and

a circuit across said assembly configured to dissipate said electrical energy and damp vibration of the body,

wherein said electroactive assembly is attached to said body in said region of strain, and

wherein said assembly includes a layer of packaging material about the strain element, and strain is coupled to said element through said packaging material.

8. A golf club, comprising:

a body having an extent and a contact surface which is subject to stimulation such that at least a portion of the body vibrates with a distribution of strain energy that includes a region of strain; and

an electroactive assembly comprising;

an electroactive strain element for transducing electrical energy and mechanical strain energy; and

a circuit across said assembly configured to dissipate said electrical energy and damp vibration of the body,

wherein said electroactive assembly is attached to said body in said region of strain, the body includes a shaft having said distribution of strain energy, the shaft extends to a head having said contact surface, and

wherein the electroactive assembly includes a first set of electroactive elements arranged on one side of a bending axis, and a second set of electroactive elements arranged on an opposite side of the bending axis, and said second set is poled oppositely to said first set and connected to a common shunt.

9. A golf club, comprising:

a body having an extent and a contact surface which is subject to stimulation such that at least a portion of the body vibrates with a distribution of strain energy that includes a region of strain; and

an electroactive assembly comprising;

an electroactive strain element for transducing electrical energy and mechanical strain energy; and

a circuit across said assembly configured to dissipate said electrical energy and damp vibration of the body,

wherein said electroactive assembly is attached to said body in said region of strain, and

wherein said electroactive strain element is electroceramic.

10. A method of damping a golf club having a shaft, such method comprising

strain-coupling an electroactive assembly to a region of the golf club located on the shaft and away from its striking surface to receive strain energy from the club and produce electrical charge therefrom, and

placing a circuit across the electroactive assembly to shunt the charge and alter strain in said region thereby changing response of the club.

11. The method of claim 10, wherein the step of placing a circuit includes shunting opposed poles of said electroactive assembly to dissipate energy received from said region.

12. The method of claim 11, wherein said electroactive assembly includes separately-electroded electroactive elements and the step of placing a circuit includes placing separate circuits across subsets of said elements to produce damping.

13. The method of claim 12, wherein the step of strain coupling an assembly to receive strain energy includes mounting the assembly near a mechanical root of said club over a region effective to receive strain energy from said implement and produce damping of at least (0.15) percent.

14. The method of claim 12, wherein the step of strain coupling the electroactive assembly includes bonding a sheet assembly to the club.

15. A method of making a damped golf club, such method including the steps of

providing a club having body parts including a head and shaft

adding to at least one body part an electroactive assembly including an electroactive strain element extending along the body part so as to efficiently couple strain between said element and said body part, and

shunting charge generated in said strain element at one or more modal frequencies of a vibrational response of the golf club.

16. A method of making a damped golf club according to claim 15, wherein the steps of adding an electroactive assembly and shunting charge at one or more modal frequencies includes adding separate regions of electroactive material which are shunted to damp distinct modal frequencies of the golf club.