|
| US4288901 | 27. Juni 1979 | 15. Sept. 1981 | | Method of manufacturing and calibrating a displacement measuring sensor |
| US4913430 | 20. Jan. 1988 | 3. Apr. 1990 | | Tennis racket strings having orthogonally directed protrusions for enhancing the grip when in contact with a tennis ball |
| US6447412 | 18. Apr. 2000 | 10. Sept. 2002 | EF Composite Technologies, L.P. | Sports racket with undulations in frame interior surface |
| US6761651 | 22. Nov. 2002 | 13. Juli 2004 | | Aluminum tennis racket |
| US6958104 | 20. Aug. 2002 | 25. Okt. 2005 | EF Composite Technologies, L.P. | Sports racket with undulations in frame interior surface |
