Games using tangible projectile – Player held and powered – nonmechanical projector – per se,... – Racket or paddle; accessory therefor
Reexamination Certificate
1999-06-25
2001-08-28
Chiu, Raleigh W. (Department: 3711)
Games using tangible projectile
Player held and powered, nonmechanical projector, per se,...
Racket or paddle; accessory therefor
Reexamination Certificate
active
06280355
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is an improvement in game rackets and their stringing and, in particular an improvement directed to the teachings of U.S. Pat. No. 4,184,679 including overcoming certain difficulties stringers found in stringing such rackets. There was resistance on the part of the stringers to learn the pattern disclosed in the '679 patent as it was found by many to be complicated to learn and too time consuming in practice. Certain tennis playing consumers, for example, did not want to buy the product disclosed in the '679 patent because it was difficult to get it restrung. Further the prior art rackets which included diagonal and horizontal string segments had the drawback that during the stringing process, when any reasonable tension was applied to the strings, distortion of the frame would occur.
Prior art three string rackets had the further complication that restringing could not in many instances be done on conventional stringing machines. Special clamps were needed to string the diagonal strings which clamps were not compatible with many stringing machines and the process of inserting verticals first took much more time than conventional stringing.
SUMMARY OF THE PRESENT INVENTION
The present inventive racket, method of stringing and stringing apparatus provide a simpler and improved system permitting racket stringing and restringing be accomplished on all stringing machines using conventional clamps or the improved clamp of the present invention. The first step in the present invention stringing method is to determine the stringing pattern having diagonal string segments and vertical or horizontal string segments. The number of string segments and the size of angles of intersection or crossovers are selected depending on the shape and size of the racket to be strung. Formulas assist in pattern formation. Once the pattern is determined holes or other siring supports are located on the racket head and the racket is ready for stringing.
Stringing starts with the placing of first and second sets of opposing diagonals on or in the string supports such that the second set overlies the first diagonal set or vice versa. The stringing of the first and second diagonal sets are accomplished by alternately inserting and subsequently tensioning string segments in each direction, generally starting at the top, mid-region or bottom of the frame. When all or substantially all of the diagonal string segments have been inserted, a set of verticals (or horizontals) are then strung by weaving them over the upper diagonals and under the lower diagonals.
The angle of the diagonal string segments are selected to avoid any shortening, widening, narrowing or other distortion of the frame. The angle of the diagonals to the racket horizontal centerline and the angle of intersection of each of the diagonals is determined based on a number of factors discussed below. Preferably, diagonal segments at approximately 45° to the horizontal centerline are used; however, diagonals more or less vertical in orientation may be used provided the diagonals have the ability to counteract the horizontal forces that would otherwise warp the racket when stringing rackets in this diagonals-first method. Preferably diagonals are in the ranges of 35°-55° or 40°-50° or 43° to 47°. Algebraic formulae serve to calculate the symmetric three-directional vertical-diagonal pattern across the racket face. A method and formula for assuring that an over/under weave is achieved throughout the string pattern is also included in the present invention.
Orthogonal crossing diagonals permit use of conventional swivel or floating clamps. Floating clamps may also be used on machines that do not have swivel clamps but use rail clamps for mains and floating clamps for diagonals.
The present invention also includes a method of stringing using racket and string identifications which are coordinated to assist in stringing.
Finally, the invention includes improved clamps which are helpful in three set stringing on some machines.
REFERENCES:
patent: 3999756 (1976-12-01), Head
patent: 4049268 (1977-09-01), Ray
patent: 4184679 (1980-01-01), Mishel
patent: 4359213 (1982-11-01), Bachman et al.
patent: 4874170 (1989-10-01), Zech
patent: 3149810 (1983-06-01), None
Hauptman Madeline Mishel
Luskin David S.
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