Abstract:
A training weight aid for a sports racquet having longitudinal strings and lateral strings strung to span its head frame and creating interstices framed by said strings has a pair of opposed shells interengaged with the strings on opposite sides thereof to provide a shell assembly within the head of the racquet. Longitudinal and lateral rows of spaced apart, shell nub projections, dimensioned and spaced to be received by the strings, extend axially into the space interstices such that many are in lateral gripping engagement with the strings. A pair of disengageable fasteners extend axially through the string space interstices to axially lock the shells together in opposing relation on the strings.

Description:
The present invention is concerned with racquet string supported training weights for use by tennis players, for example, in warm-up exercising prior to playing, and in general conditioning and stroke perfection exercising. The present application claims the priority of provisional application 60/073,187 filed Jan. 30, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     Various weighting devices have been previously proposed for accomplishing the functions to be performed. Most, to our knowledge, have involved racquet frame supported weighting devices and some have been of a permanently secured nature, or nature which rendered ready removal and resecural difficult. Devices which have been suggested for application to the racquet strings have not, to our knowledge, interacted with the strings in the manner contemplated by the present invention to secure the assembled weighting system in position. 
     SUMMARY OF THE INVENTION 
     One of the prime objects of the present improved string supported weighting system is to provide a multi-purpose device useful in a sport specific manner to stretch the arm muscles and warm-up the shoulder and torso muscles which are used in games such as tennis. 
     Another object of the invention is to provide a weighting device of the character described which, with use over time, strengthens the muscles used in racquet sports, such as tennis, and improves their conditioning and flexibility. Used on a regular basis, the device enhances the neuro-muscular training that is necessary for the development of technically sound tennis strokes. 
     Still another object of the invention is to provide a readily removable and reattachable string supported weighting system which enhances stroke perfection and control in that swinging, preferably, the users own racquet with the device attached assists bringing the head of the racquet through the stroke and better trains the follow-through motion. 
     A further object of the invention is to provide a weighting assembly which grips the strings in a manner to prevent any deleterious lateral shifting or rotation of the secured mating halves of the assembly, and interacts with the strings without damaging them. 
     A still further object of the invention is to make available a relatively economical, effective muscle training weight device which is also durable and reliable. 
     Another object of the invention is to provide a new method of fabricating weighting devices of the character to be described and a new method of securing the parts in position on the strings. 
     In the environment of a strung racquet having a handle merged with an enlarged frame head with crisscrossed strings strung in the head frame under tension and providing interstitial openings between the crisscrossed strings, the improvement invention contemplates an improved weighting device to be carried safely by the strings comprising: 
     a. a pair of mating shell-like halves having confronting perimetral flanges or surfaces; 
     b. a string related pattern of discrete flexible nub-like projections extending axially from the shell flanges into the racquet&#39;s interstitial string spaces, a plurality of the projections laterally engaging the strings to laterally stabilize the assembled position of the shell halves; and 
     c. a fastener system having parts or surfaces engagable to fasten the halves axially together. 
     More specifically the fastener system which locks the shell halves together comprises revolvable lock posts which extend in diametral orientation through the mating flanges of the assembled shell halves and which can be manually revolved from a fastened rotary position to a nonfastened rotary position. The posts are laterally spaced apart a distance which permits them to pass through spaced apart string interstices and positions the nub-like projections generally to do the same. 
    
    
     THE DRAWINGS 
     The presently preferred embodiment of the invention is disclosed in the following description and in the accompanying drawings, wherein: 
     FIG. 1 is a plan view diagrammatically showing the weighting device assembled on a typical tennis racquet; 
     FIG. 2 is an enlarged fragmentary exterior elevational view of a portion of the racquet frame; 
     FIG. 3 is a top plan view of the assembled device, partly broken away to illustrate the interaction with the racquet strings; 
     FIG. 4 is a sectional view through the racquet strings and assembled device taken on the line 4--4 of FIG. 3, the strings and weighting device nubs being only partly illustrated in the interests of clarity; 
     FIG. 5 is a side elevational view of a non-ribbed version of one of the shell halves; 
     FIG. 6 is a side elevational view of one of the identical assembly lock posts; 
     FIG. 7 is an end elevational view thereof; and 
     FIG. 8 is a top plan view thereof. 
    
    
     DETAILED DESCRIPTION 
     Referring now more particularly to the accompanying drawings, the racquet depicted, generally indicated at R, includes a handle 10 merged with a head, generally indicated at 11, which includes a substantially rigid frame portion 11a having crisscrossed interlaced strings S. The strings S include vertical string portions 12 and horizontal string portions 13 which extend relatively generally at right angles through the frame string openings or the like, which are shown at 14 in FIG. 2, and predetermine the string spacing. Ferrules 14a may be provided to protect the strings S. 
     Immobily clamped on the strings S in a position which normally would be horizontally central but may vary from the vertically central position in which it is shown, is my improved weighting assembly or system, generally designated W. The weighting assembly weight, training aid, or weight device, generally designated W, comprises a pair of identical annular shells, or shell-like halves 15 and 15a having mating annular perimetral flange portions or surfaces 16 and central dome portions 17 with strengthening ribs 17a extending from rib cores 17b. The halves 15 and 15a may be molded of a synthetic thermoplastic rubber material or elastomer which is somewhat resilient such as the material known as Starflex P-7360 manufactured by Star Thermoplastic Alloy and Rubbers, Inc. of Glenview, Ill., which has a durometer rating of sixty. 
     Extending generally perpendicularly from the flanges surfaces or portions 16 of shells 15 and 15a are axially mating nub projections 16a of a rubbery, somewhat deformable and flexible nature which are provided in a racquet string pattern as shown to extend axially into the string interstices or openings defined by the vertical and horizontal strings 12 and 13. In assembled position, a number of the nubs 16a, which have rounded free ends as shown, lie adjacent to at least a number of the strings 12 and 13 (see FIG. 3) and bear laterally against them when any force is applied which would tend to shift the assembled device W on the strings. With the nubs 16a having some deformability, and, in fact, the whole device being molded out of the same deformable material, the strings 12 and 13 which, of course, may be formed of a suitable plastic or gut material are resiliently gripped by the assembly device W. 
     Typically the horizontal strings 12 and the vertical strings 13 are located about 3/8 of an inch apart, but, of course, this spacing varies to some extent from racquet to racquet. 
     Provided diametrally (see FIGS. 3 and 4) in the shell halves 15 and 15a are openings or passages 18 on one side of each of the halves 15 and 15a and openings or passages 19 on the other. The openings 18 have an enlarged partial counterbore 18a and an enlarged portion 18b connected by a reduced diameter portion 18c. They are provided for receiving and retaining a revolvable lock post, generally designated P. Post P includes stem portion 20, an end cap 20a of greater diameter than the opening 18 so as to be retained within counterbore 18a, and a flange 20b which is received within opening portion 18b. On the opposite end of each post P is an integral enlarged lock blade 21 with its shoulder 21a. It is to be noted that the otherwise annular openings 19 have slitted portions 19a of a size to slideably axially pass the blades 21 and shoulders 21a, when the blades 21 are in alignment with them. 
     An enlarged portion or counterbore 19b provided at the outer end of each passage 19, provides a lock shoulder 19c and permits rotation of each post P from a position in which the blade 21 aligns with the slits 19a to a position in which it does not and engages the shoulder 19c to lock the mating halves 15 and 15a in assembled position. The openings 18 and 19, in their respective shell halves 15 and 15a, are located a predetermined diametral distance apart, which considers the spacing of the strings and the positions of the nub projections 16a. By having openings 18 and 19 in each of the halves 15 and 15a, the halves 15 and 15a can be, and typically are, fabricated in the same mold. Typically the post P is molded of a harder more rigid material, such as nylon. 
     The Operation 
     To assemble the weighting assembly W on the strings S is a relatively simple operation. It is only necessary to dispose the mating halves 15 and 15a on opposite sides of the racquet face in the desired position with the respective post blades 21 in a position of alignment with the slits or slots 19a which are to receive and pass them. The posts P are so diametrally positioned that they will extend through the interstices or openings 0 provided between the strings 12 and 13 and act, in this regard, to align the shell halves 15 and 15a so that the nub-like projections 16a substantially axially align also. Once the blades 21 are extended through the slits 19a, they may be grasped and rotated sufficiently through a part of a turn such that their inner edges overlie the locking shoulder surface 19c. When this occurs, the projections 16a, or many of them, will be in the positions shown in the broken away portion in FIG. 3. 
     The removal of the halves 15 and 15a from the racquet may be as readily accomplished in reverse order by simply turning the posts P until the blades 21 line up with the slitted openings 19a and then pulling the halves 15 and 15a apart. 
     When in assembled position, the weighting device will typically weigh slightly less than half a pound. In assembled position, a plurality of the nubs 16a laterally grip the strings with which they are in contact, and prevent lateral displacement of the device on the strings S. Because the halves 15 and 15a can be so readily disassembled, the weighting device W can be used on the player&#39;s own racquet which, of course, is the racquet with which the player and his or her muscles are familiar. 
     Method of Making 
     In practice, the mold halves 15 and 15a are molded in the same or identical molds, without the posts P in position. The posts P are molded of a different more rigid material and, just after the thermoplastic halves 15 and 15a are removed from the mold and are still warm and most deformable, the posts P can be readily pressed axially into the openings 18. The heads 20 of the post are of such diameter that they can be pressed up through the openings 18, which deform laterally sufficiently to permit them to pass. The final position of the posts P is predetermined by the entry of the annular flanges 20b into the openings 18b. 
     Typical thermoplastics which we contemplate may be molded to form shells 15 and 15a are the conventional elastomers, such as styrene-butadiene block copolymers and the urethane elastomers, which are well known and commercially available. Other plastics or materials may also be used for the locking posts. 
     The disclosed embodiment is representative of a presently preferred form of the invention, but is intended to be illustrative rather than definitive thereof. The invention is defined in the claims.