US2020612A - Tennis ball - Google Patents

Description

Nov. 12, 1935. J. T. MCGRATH ET AL.

TENNIS BALL Filed Aug. 29, 1934 Patented Nov. 12, 1935' UNITED STATES PATENT OFFICE TENNIS BALL Application August 29, 1934, Serial No. 741,923

7 Claims- (Cl. 273-61) The present invention relates to balls of the type used in playing tennis, that is; inflated hollow balls of rubber composition covered with felt or cloth. It is concerned mainly with the covering, and its object is to provide a covered ball of this character of which the covering will be more durable in the preservation of the playing qualities of the ball.

Tennis ball covers, whether made as a fabric woven and felted or of fibers felted without preliminary spinning and weaving, always have a relatively heavy nap, which may be that Worked up by a fulling operation, or produced by a napping machine, and the nap is an important factor in the playing qualities of the ball. The quality of roughness which it possesses enables an expert player to exercise control over the flight of the ball after being struck by the racquet; such control resulting from the spin imparted to the ball by the manner in which the racquet impinges upon it, and by the friction of the air on the surface of the spinning ball in flight. According to the manner in which a player strikes a ball with his racquet he can cause it to deviate from a straight line in flight and to make a more or less abrupt drop, or other desired change of direction in a predetermined portion of its trajectory. But in order that such a measure of control may be obtained, the ball must have a proper surface, with a certain roughness, but be not too rough.

In the course of playing, the nap rapidly wears away, due partly to the impact of the racquet, but in greater measure to the impact of the ball on the ground, so that the surface soon becomes too smooth to afford the control which the player requires. When this condition occurs the ball fails to drop or curve in the manner expected by the player from the character of the spin applied to it by the stroke of the racquet. The flight of the ball in the course which it takes when such loss of control occurs is called floating or sailing, in the parlance of the game. When a ball begins to float it is useless for expert playing. For this reason new balls are always used at the commencement of tennis matches; and old balls are discarded long before their value in other particulars is sensibly diminished.

Having regard to the foregoing explanation, we may now state our object more definitely as being to provide a new design and construction of covered tennis ball which will present to the influence of the air, as the cover wears down, such a new surface as will keep the flight of the ball true and thereby minimize the so-called floating or sailing f the ban, and will also,

avoid excessive loss of weight; thus increasing the useful life of the ball as an article suited for the use of expert players. While the purposes and utility of the invention are primarily and mainly concerned with tennis balls, it is to be understood that the protection which we claim is not limited as to the use to which the balls, made in accordance with it, may be put. It includes balls of all descriptions and constructions which are provided with felt covers and in which the novel characteristics of our covered balls have utility.

In the drawing herewith presented there is illustrated the invention,--

Fig. 1 is an elevation of a tennis ball covered 1 with felt material embodying the novel characteristics of this invention and represented with the nap removed from a portion of its surface to reveal the weave of the fabric;

Fig. 2 is a weavers diagram showing illustratively a suitable base construction for the covering material.

The core or body of the ball in which our invention is embodied may be of any known or otherwise suitable character; for instance, the standard inflated hollow sphere of rubber composition prescribed by the rules of the National Tennis Association. The new features of the invention consist in the cover and in the combination of the ball and the cover.

Briefly stated, the cover is a woolen fabric woven with a basket weave, fulled to a satisfactory condition of weight, density, and felted or napped surface, and sheared. The weight and number of constituent yarns and the extent of fulling to which the woven fabric is subjected are such as will bring the finished felt to the weight and thickness prescribed by the rules of the tennis associations. But within these limitatio-ns, and for uses to which such specific limitations do not apply, the yarns may be considerably varied in size and in their arrangement in the basket weave. For instance, the weave may be made with from four to twelve ends of warp and. an equal number of picks of weft in each repeat of the pattern; but we find that a six, eight or ten harness weave is preferable to those in which there are either more or fewer yarns in each mesh of the fabric. In any case the warp and Weft yarns are of the same size. The illustrative dia- 0 gram shown in Figure 2 of the drawing represents a four yarn (eight harness) weave; i. e., one in which adjacent ends of warp and picks of weft cross one another in groups of four.

We have found that weaves of the character after wearing away of the nap.

above described produce thoroughness of surface after the wearing away of the original nap that is needed to maintain substantially equal efiectiveness of control by the player as is afforded by the unworn nap of the new ball.

For the further information of those skilled in'the art, it may be stated that the weaving and fulling steps are preferably carried out in accordance with known practice so as to obtain the prescribed weight per yard and thickness of finished material with a single ply weave, and to obtain in the neighborhood of eight repeats of the pattern per inch of width and length of the finished felt when constructed with an eight harness weave; or a relatively larger or smaller number of repeats according as fewer or more, respectively, ends of warp and picks of weft are placed at each crossing point of the basket pattern. The further steps of shearing, cutting thefelt in pieces suitable to form a spherical cover, and applying such pieces to the surface of the ball core, are, or may be, the same as those heretofore used in making and applying felt covers.

It is to be understood, however, that the foregoing specific description, dimensions, etc. are not intended as limitations in the protection which we seek. Suitable variations may be made if the cover material is to comply with other standards or if it may be made without referencelto con ventional standards or specificationsi So also the thickness and spacing of the constituent yarns may be considerably varied within the scope of V the invention, provided the result is a structure which attains substantially the utility and advantage herein described.

When new, the texture of the covering is largely overlaid and obscured by the mat or nap of the broken twill weave,. which is the foundation of the tennis ball felts heretofore generally used, The frictional effect of such checkered ribbed surface on the air when the ball spins is substantially the same whatever the direction of spin may be, and is substantially different from that of'the broken twill cover when worn smooth. The exposed texture of the latter has'a definite grain, of which length of'the unconfined portions of the strands where they cross over a plurality of underlying strands, and they maintain surface conditions largely similar to the original condition for a long time.

These factors prevent floating or sailing long after the original nap has been worn off, and for a much greater length of play than is afforded by balls heretofore available. Based on the number of games during which they can be used before objectionable floating becomes evi- 5 dent, balls made in accordance with this invention show from 60% to 80% improvement over the best balls of the prior art.

What we claim and desire to secure by Letters Patent is:- 1. A ball of the felt covered type having a cover of woven and felted woolen yarns in which theyarns are arranged in a basket weave.

2. A ball of the type of the felt covered tennis ball having a cover composed of woolen yarns, disposed in a basket weave of which both warp and weft have substantially the same characteristics. a

3. A ball of the felt covered tennis ball type having a cover composed of woolen yarn, woven in a basket weave,-fulled to substantially increased thickness, but without distortion of the orderly arrangement of warp and weft yarns; the arrangement of yarns being such that upon l'wearingaway of the original nap, the new surface is substantially rougher than that of. a oneto-one weave of the same yarns, whereby to minimize so-called floating. or sailing of the ball. 4. A felt covered tennis ball having a felted surface and woven construction of basket formation beneath the surface, such as to form a sufficiently rough surface, after the wearing ,away of the original nap, to prevent floating or sailing of the ball in play.

5. A tennis ball having a woven covering in which the warp and weft strands cross each other'in groups, forming a basket pattern of substantially greater roughness than that of a broken twill weave of the same strands, whereby the tendency of'the ball to float or sail in 40 play is made substantially less than that of a like ball covered with such fabric of broken twill weave. V

'6. A tennis ball having a woven and fulled woolen covering in which the warp and weft strands are arranged in a basket pattern, crossing one another in groups of strands laid side by side, whereby a roughness of surface is produced, after wearing away the original nap, substantially greater than that of a fabric woven of the same strands in a broken twill pattern and fulled, after wearing away of its original nap.

7. A tennis ball having a woven covering constructed of woolen warp and weft strands all of the same size, and of which the weft strands cross the warp strands, and vice versa, in groups of parallel strands lying side by side, there being an equal number of such parallel strands, of equal length, exposed on the surface of the texture at'each'crossing point; said coveringbeing fulled and having'a surface nap; the woven structure when exposed by wearing away of the original nap providing a roughsurface and enabling fibers frayed from the overlying strands of the texture to form substantially a new nap having the effect of substantially diminishing the tendency of the ball'to float or sail in play. a

' JOHN T. MCGRATH.

RODNEY B. WILMAN.

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