Patent US4736949A successfully refreshed from Google Patents.
US4736949A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Racket frame having particularly positioned grip
Assignee: Yamaha Corp
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Filing: 1986-09-08
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Granted: 1988-04-12
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Expires: 2006-09-08
Abstract
Abstract The present invention provides a racket frame with a grip which includes an inner low rigidity layer embracing the rear end section of a shaft and an outer high rigidity layer embracing the inner low rigidity layer and partly in direct contact with the shaft, the direct contact being at the position of the node of the primary vibration transmitted through the shaft when striking a ball.
Inventors
- 👤 Kunimasa Muroi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:26
CPC Classifications
A; A63; A63B; A63B49/00; A63B49/02; A63B49/08; A63B60/00; A63B60/54; A63B60/0081; A63B60/06; A63B60/08; A63B60/10; Y; Y10; Y10S; Y10S273/00; Y10S273/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
91 words
An improved racket frame comprising a shaft and a grip formed on the rear end section of said shaft, said grip including an inner low rigidity layer embracing said rear end section of said shaft and an outer high rigidity layer embracing said low rigidity layer, said inner and outer layers being of different rigidity, said outer high rigidity layer being in direct contact with the rear end section of the shaft only at the position of the node of the primary vibration transmitted through said shaft when striking a ball.
Claim 2
Dependent Claim
91 words
An improved racket frame comprising a shaft and a grip formed on the rear end section of said shaft, said grip including an inner low rigidity layer embracing said rear end section of said shaft and an outer high rigidity layer embracing said low rigidity layer, said inner and outer layers being of different rigidity, said outer high rigidity layer being in direct contact with the rear end section of the shaft only at the position of the node of the primary vibration transmitted through said shaft when striking a ball.
Claim 3
Dependent Claim
22 words
The improved racket frame as claimed in claim 1 in which said inner low rigidity layer is made of foam synthetic resin.
Claim 4
Dependent Claim
21 words
The improved racket frame according to claim 1 in which said outer high rigidity layer is made of non-foam synthetic resin.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-12 | 1991-10-12 | 1992-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-12 | 1995-10-12 | 1996-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-12 | 1999-10-12 | 2000-04-12 | $7700.00 | Window Closed / Lapsed |