Synthetic string for sporting application
AssigneePrince Manufacturing, Inc.
InventorsKenneth A. Stevens, David T. Holland
Life of this patent
Estimating the term…
Abstract
A string for sports application, in particular for tennis, badminton, racquetball and squash racquets or the like comprises a center core and at least one ribbon-like wrap made of a highly abrasion resistant material which exhibits a higher melting point and at least one of a higher dynamic stiffness and a lower static stiffness than the core material. A preferred wrap material meeting the above criteria is poly(m-phenylene isophthalamide). The wrap should cover at least 25%, and preferably at least 50% of the center core's outer surface to reduce notching. Due to the reduced notching, superior combined properties of durability, playability and minimal loss of string tension are achieved.
Claims53
A string for sports applications comprising:
- a core composed of at least one material having a first melting point and a first static stiffness;
- a protective layer of an abrasion resistant material covering at least a portion of the core to protect the core from wear, the abrasion resistant material having a second melting point and a second static stiffness;
- and
- an outer sheath means for sealing the surfaces of the core and the protective layer,
- wherein the first melting point is lower than the second melting point and the first static stiffness is higher than the second static stiffness.
A string for sports applications comprising:
- a core composed of at least one material having a first melting point and a first dynamic stiffness;
- a protective layer of an abrasion resistant material covering at least a portion of the core to protect the core from wear, the abrasion resistant material having a second melting point and a second dynamic stiffness;
- and
- an outer sheath means for sealing the surfaces of the core and the protective layer,
- wherein the first melting point is lower than the second melting point, and the second dynamic stiffness is higher than the first dynamic stiffness by up to 25%.
A string for sports applications comprising:
- a core composed of at least one material having a first melting point, a first dynamic stiffness and a first static stiffness;
- a protective layer of an abrasion resistant material covering at least a portion of the core to protect the core from wear, the abrasion resistant material having a second melting point, a second dynamic stiffness and a second static stiffness;
- and
- an outer sheath means for sealing the surfaces of the core and the protective layer,
- wherein the first melting point is lower than the second melting point, the first static stiffness is higher than the second static stiffness, and the second dynamic stiffness is higher than the first dynamic stiffness by up to 25%.
A string for sports applications comprising:
- a core composed of at least one material having a first melting point, a first dynamic stiffness and a first static stiffness;
- an abrasive resistant protective layer consisting essentially of poly(m-phenylene isophthalamide) covering at least a portion of the core to protect the core from wear, the abrasion resistant protective layer having a second melting point, a second dynamic stiffness and a second static stiffness;
- and
- an outer sheath means for sealing the surfaces of the core and the protective layer,
- wherein the first melting point is lower than or equal to the second melting point, the first dynamic stiffness is lower than or equal to the second dynamic stiffness, and the first static stiffness is higher than or equal to the second melting point.
A string for sports applications comprising:
- a core consisting of a first material;
- a protective layer consisting of two 180.degree. spaced apart ribbon-like wraps consisting essentially of poly(m-phenylene isophthalamide), helically wrapped around the core in the same direction and covering at least 50% of the surface of the core;
- and
- an outer sheath means for sealing the surfaces of the core and the protective layer,
- wherein the first material is other than poly(m-phenylene isophthalamide) and wherein when the string is incorporated in a string bed, the RA string-bed stiffness thereof is reduced on average only up to about 1.5% measured by the dynamic tension loss test.
A string for sports application comprising a string having a diameter of 1.33 mm, an extrapolated dynamic stiffness of up to about a maximum of 14,000 at 60 pounds and a durability of at least about 558 at 60 pounds.
A sports racquet strung with a string comprising:
- a core composed of at least one material having a first melting point and a first static stiffness;
- a protective layer of an abrasion resistant material covering at least a portion of the core to protect the core from wear, the abrasion resistant material having a second melting point and a second static stiffness;
- and
- an outer layer means for sealing the surfaces of the core and the protective layer,
- wherein the first melting point is lower than the second melting point and the first static stiffness is higher than the second static stiffness.
Dependencies are inferred from the claim text.