Sports implement
First Claim
1. A racquet comprisinga body having an extent and including a contact surface which is subject in use to stimulation such that the body vibrates with a distribution of strain energy in said body including a region of strain, an electroactive assembly including an electroactive strain element for transducing electrical energy and mechanical strain energy, said electroactive assembly being attached to said body in said region of strain, and a circuit across said assembly configured to dissipate said electrical energy and damp vibration of the body, wherein said circuit is mounted in a sheet assembly.
2 Assignments
0 Petitions
Accused Products
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.
-
Citations
24 Claims
-
1. A racquet comprising
a body having an extent and including a contact surface which is subject in use to stimulation such that the body vibrates with a distribution of strain energy in said body including a region of strain, an electroactive assembly including an electroactive strain element for transducing electrical energy and mechanical strain energy, said electroactive assembly being attached to said body in said region of strain, and a circuit across said assembly configured to dissipate said electrical energy and damp vibration of the body, wherein said circuit is mounted in a sheet assembly.
-
8. A method of damping a racquet having a shaft, such method comprising
strain-coupling an electroactive assembly to a region of the racquet located on the shaft and away from its striking surface to receive strain energy from the racquet 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 racquet, wherein the step of placing a circuit includes shunting opposed poles of said electroactive assembly to dissipate energy received from said region.
-
11. A racquet comprising
a body having an extent and including a contact surface which is subject in use to stimulation such that the body vibrates with a distribution of strain energy in said body including a region of strain, an electroactive assembly including an electroactive strain element for transducing electrical energy and mechanical strain energy, said electroactive assembly being attached to said body in said region of strain, and a circuit across said assembly configured to dissipate said electrical energy and damp vibration of the body, wherein said circuit is an inductive shunt for dissipating charge generated by strain coupled from said region of strain into said element.
-
18. A racquet comprising
a body having an extent and including a contact surface which is subject in use to stimulation such that the body vibrates with a distribution of strain energy in said body including a region of strain, an electroactive assembly including an electroactive strain element for transducing electrical energy and mechanical strain energy, said electroactive assembly being attached to said body in said region of strain, and a circuit across said assembly configured to dissipate said electrical energy and damp vibration of the body, wherein said strain element is embedded in a shaft formed of composite material.
Specification