US4183200A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tennis racket string
Assignee: Wilson Sporting Goods Co
•
Filing: 1977-10-03
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Granted: 1980-01-15
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Expires: 1997-10-03
Abstract
Abstract A string for a tennis racket composed of a synthetic resin such as nylon and having a combination of properties which provides a highly desirable balance between playability and durability. Specifically, the string has a spring rate of from 45 to 65 pounds/inch (8.0 to 11.6 kg/cm) at a loading in the range of 50 to 100 pounds (22.7 to 45.4 kg), the string exhibiting a substantially linear stress-strain behavior in the foregoing range, a minimum tensile break load of 120 pounds (54.4 kg), a thickness of from 0.040 to 0.055 inch (0.10 to 0.14 cm), a minimum overhand knot strength of 50 pounds (22.7 kg), and a minimum surface friction of 0.120.
Inventors
- 👤 Girdhar Bajaj
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:42
CPC Classifications
A; A63; A63B; A63B51/00; A63B51/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
157 words
A tennis racket string comprising a solid mono-filamentary core having strands wound thereabout and adhesively secured thereto without degradation of the strands, both said core and said strands being composed of a synthetic resin, said core having a thickness of three to six times the thickness of the strand, said string having a spring rate of from 45 to 65 pounds/inch (8.0 to 11.6 kg/cm) at a loading in the range of 50 to 100 pounds (22.7 to 45.4 kg), said string exhibiting a substantially linear stress-strain behavior in said range, a minimum tensile break load of 120 pounds (54.4 kg), a total thickness of from 0.040 to 0.055 inch (0.102 to 0.140 cm), a minimum overhand knot strength of 50 pounds (22.7 kg), and said strands being encased by a separate continuous, smooth outer resin layer composed solely of a set resin adhesive bonded to the string thereby providing said string with an improved surface texture.
Claim 2
Dependent Claim
157 words
A tennis racket string comprising a solid mono-filamentary core having strands wound thereabout and adhesively secured thereto without degradation of the strands, both said core and said strands being composed of a synthetic resin, said core having a thickness of three to six times the thickness of the strand, said string having a spring rate of from 45 to 65 pounds/inch (8.0 to 11.6 kg/cm) at a loading in the range of 50 to 100 pounds (22.7 to 45.4 kg), said string exhibiting a substantially linear stress-strain behavior in said range, a minimum tensile break load of 120 pounds (54.4 kg), a total thickness of from 0.040 to 0.055 inch (0.102 to 0.140 cm), a minimum overhand knot strength of 50 pounds (22.7 kg), and said strands being encased by a separate continuous, smooth outer resin layer composed solely of a set resin adhesive bonded to the string thereby providing said string with an improved surface texture.
Claim 3
Dependent Claim
15 words
A tennis racket string according to claim 1 in which said synthetic resin is nylon.
Claim 4
Dependent Claim
17 words
A tennis racket string according to claim 1 which has a damping capacity of 0.470 to 0.750.
Claim 5
Dependent Claim
20 words
A tennis racket string according to claim 1 which has a 180° bend fatigue value of at least 5 minutes.
Claim 6
Dependent Claim
23 words
A tennis racket string according to claim 1 which has a double loop strength of at least 90% of its minimum knot strength.
Claim 7
Dependent Claim
23 words
A tennis racket string according to claim 1 which has a uniform thickness of from 0.045 to 0.0530 inch (0.114 to 0.135 cm).
Claim 8
Dependent Claim
19 words
A tennis racket string according to claim 1 which has a minimum break load of 135 pounds (61.2 kg).
Claim 9
Dependent Claim
19 words
A tennis racket string according to claim 1 which has a minimum knot strength of 70 pounds (31.8 kg).
Claim 10
Dependent Claim
18 words
A tennis racket string according to claim 1 which has a surface friction of from 0.150 to 0.400.
Claim 11
Dependent Claim
135 words
A tennis racket string comprising a solid core of nylon mono-filament and nylon strands of substantially less thickness wound about said core and adhesively secured thereto without degradation of the strands, said string having a spring rate of 45 to 65 pounds/inch (51.8 to 74.9 kg/cm) at a loading in the range from 50 to 100 pounds (22.7 to 45.4 kg) and exhibiting a substantially linear stress-strain behavior in said range, a total thickness of from 0.045 to 0.0530 inch (0.114 to 0.135 cm), a minimum break load of 135 pounds (61.2 kg), a minimum knot strength of 70 pounds (31.8 kg), and said strands being encased by a separate, continuous, smooth outer resin layer composed solely of a set resin adhesive bonded to the string, thereby providing said string with an improved surface texture.
Claim 12
Dependent Claim
135 words
A tennis racket string comprising a solid core of nylon mono-filament and nylon strands of substantially less thickness wound about said core and adhesively secured thereto without degradation of the strands, said string having a spring rate of 45 to 65 pounds/inch (51.8 to 74.9 kg/cm) at a loading in the range from 50 to 100 pounds (22.7 to 45.4 kg) and exhibiting a substantially linear stress-strain behavior in said range, a total thickness of from 0.045 to 0.0530 inch (0.114 to 0.135 cm), a minimum break load of 135 pounds (61.2 kg), a minimum knot strength of 70 pounds (31.8 kg), and said strands being encased by a separate, continuous, smooth outer resin layer composed solely of a set resin adhesive bonded to the string, thereby providing said string with an improved surface texture.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-01-14 | 1983-07-16 | 1984-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-14 | 1987-07-16 | 1988-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-14 | 1991-07-16 | 1992-01-15 | $7700.00 | Window Closed / Lapsed |