US3605252A

US3605252A - Method of forming a tennis racquet

Info

Publication number: US3605252A
Application number: US797591A
Authority: US
Inventors: Samuel W Landsman; Joseph A Woltering
Original assignee: MIDLAND SPORTING GOODS CO Inc
Current assignee: MIDLAND SPORTING GOODS CO Inc
Priority date: 1969-02-07
Filing date: 1969-02-07
Publication date: 1971-09-20
Anticipated expiration: 1988-09-20

Abstract

VENTIONAL WOODEN TENNIS RACQUET FRAME STRUCTURE. THE FRAME MAY BE SUITABLY STRUNG TO COMPLETE THE UNIT.
A METHOD OF FORMING A TENNIS RACQUET STRUCTURE OR THE LIKE BY CASTING THE STRUCTURE FROM FUSED METAL UNDER A PRESELECTED HIGH PRESSURE SUITABLE TO DENSIFY THE METAL TO HAVE A STRENGTH AT LEAST SUBSTANTIALLY THAT OF A CON-

Description

Sept. 20, 1971 s.w. LANDsMAN Erm. 3,605,252

METHOD OF FORMING A TENNIS RACQUET Filed Feb. 7, 1969 A75 j' f1.

nz/QnTS.' zmuc Wj; ands maw JOS @0n/wam@ 3 605 252 METHOD F FORMING A TENNIS RACQUET Samuel W. Landsman and Joseph A. Woltering, Chicago, Ill., assignors to Midland Sporting Goods Company,

Inc.

Filed Feb. 7, 1969, Ser. No. 797,591 Int. Cl. B23p 19/04 U.S. Cl. 29-433 5 Claims ABSTRACT OF THE DISCLOSURE A method of forming a tennis racquet structure or the like by casting the structure from fused metal under a preselected high pressure suitable to densify the metal to have a strength at least substantially that of a conventional wooden tennis racquet frame structure. The frame may be suitably strung to complete the unit.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to metal forming processes and, in particular, to processes for forming metal tennis racquet frames and the like.

Description of the prior art In the conventional metal frame tennis racquet, the frame may be formed by conventional metal forming techniques such as casting. It has been found, however, that such cast tennis racquets are relatively weak and do not have a strength corresponding to that of conventional wooden tennis racquets. Substantial stresses are induced in the racquet frame in the use of the racquet, and such forces have been found to prevent the satisfactory formation of such metal frame racquets by such conventional casting processes.

SUMMARY OF THE INVENTION The present invention comprehends an improved method of forming such a metal tennis racquet structure, including the steps of providing a die having a cavity corresponding to a tennis racquet frame configuration, introducing fused metal into the cavity, applying a preselected pressure to the metal in the cavity to densify the metal to form a cast frame structure having a strength at least substantially that of a conventional wooden tennis racquet frame, and stringing the cast metal frame.

More specically, the invention comprehends the provision of such a method wherein the metal comprises aluminum. Still further more specifically, the invention comprehends the provision of such a method wherein the frame configuration comprises a one-piece structure.

The invention further is directed to the concept of forming a tennis racquet structure including the steps of casting a metal frame and stringing the cast frame, the metal being cast under a pressure preselected to cause the strung frame to play a conventional tennis ball similarly to the play thereof by a conventional wooden strung racquet.

Further, the invention comprehends the provision of a tennis racquet frame structure comprising a body of fluidized material set under high pressure. As disclosed, the iluidizing material may comprise molten metal such as aluminum.

DESCRIPTION OF THE DRAWING Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein FIG. 1 is a fragmentary front view of a tennis racquet structure embodying the invention;

ice

FIG. 2 is a fragmentary section of a casting apparatus, illustrating a iirst step in the casting of the tennis racquet frame; and

FIG. 3 is a fragmentary section illustrating a final step in the casting of the tennis racquet frame.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the exemplary embodiment of the invention as disclosed in the drawing, a tennis racquet generally designated 10 is shown to include a frame 11 having a striking portion 12 and a handle portion 13. The striking portion is provided with a plurality of stringing holes 14. Stringing 15 is strung through the holes as shown in FIG. 1 to provide a ball striking means.

The racquet 10 is generally similar to the conventional wooden frame racquet and is adapted to provide a play of a conventional tennis ball similar to the play thereof by conventional wooden frame racquets. The frame 11, however, is formed of a suitable cast metal to provide improved life with effectively minimum cost. Illustratively, the frame 11 may be formed of cast aluminum, it being understood that other suitable castable materials may be utilized.

The invention comprehends the forming of the cast frame by a conventional pressurized casting process. An excellent example of such a process is that developed by General Motors Corporation and identified as the Acurad process.

As shown in FIG. 2, in the illustrated embodiment of the invention, a casting mold generally designated 16 is provided having a suitable cavity 17 corresponding to the tennis racquet frame 12. In illustrating the invention, the frame is shown as a one-piece frame, it being understood that the frame may be cast in separate portions such as complementary half portions suitably secured together as by riveting or the like. The invention comprehends providing the cast meal 18 to the cavity 17 under substantial pressures by means of a plunger structure 19. In applying the relatively high pressures, the plunger irstly urges the cast metal into the cavity by means of an outer plunger portion 20 and subsequently by a smaller inner plunger portion 21, as illustrated in FIGS. 2 and 3 respectively. The specific densifying process forms no part of the present invention, it being merely understood that any suitable process for providing densied cast frame structures wherein the fused material is cast under substantial pressures may be employed within the scope of the invention. However, the invention comprehends specifically forming the cast metal frame structure to have a strength at least substantially that of a conventional wooden tennis racquet frame. Thus, the densifying pressures are preselected in following the present invention to provide such a preselected strength.

The invention further comprehends the forming of the frame structure under a suitable pressure to cause the cast metal frame to provide a support for the stringing such that the strung frame plays a conventional tennis ball similarly to the play thereof by conventional wooden strung racquets.

As shown in FIGS. 2 and 3, the iiuidized material 18, herein comprising molten metal such as molten aluminum, is firstly urged into the cavity 17 by the concurrent movement of the large plunger 20 and small plunger 21 of the plunger structure 19.

A higher pressure is then applied to the metal to densify the metal to have the preselected strength discussed above by moving the small plunger 21 further as shown in FIG. 3. By suitably selecting the pressures, the above discussed desired preselected strength and strung frame play may be obtained, thereby providing a low-cost, longlife racquet structure 10 in a novel and simple manner.

The handle portion 13 may he provided with an outer handle covering 22 as shown in FIG. 1, if desired. The racquet structure thusly is extremely simple and economical of manufacture while being light in weight, while yet providing high strength and long play life,

While we have shown and described one embodiment of our invention, it is understood that it is capable of many rnodications. Changes, therefore, in the construction and arrangement may be made within the spirit and scope of the invention as dened in the appended claims.

We claim:

1. The method of forming a tennis racquet structure comprising the steps of: providing a die having a cavity corresponding to a tennis racquet frame conguration; introducing fused metal into the cavity; applying a preselected pressure to the metal in the cavity to density the metal to form a cast frame structure having stringing apertures dened by the dense cast metal, said frame structure having a strength at least substantially that of a conventional wooden tennis racquet frame; and stringing the cast metal frame.

2. The method of forming a tennis racquet structure of claim i1 wherein said metal comprises aluminum,

3. The method of forming a tennis racquet structure 4 of claim 1 wherein said frame contiguration comprises a one-piece structure.

4. The method of forming a tennis racquet structure of claim l further including the step of forming a handle portion in association with a portion of said cast metal frame structure.

5. The method of forming a tennis racquet structure of claim 1 wherein said metal is cast under a pressure preselected to cause the strung frame to play a conventional tennis ball similarly to the play thereof by a conventional wooden strung racquet.

References Cited UNITED STATES PATENTS 1,153,258 9/1915 Robinson l64-l20 1,186,283 6/1916 Coddington 273-73H 1,548,134 8/1925 Gallaudet 273-73H 3,270,383 9/1966 Hall et al. 164-120 20 CHARLIE F. MOON, Primary Examiner Us. C1. XR. 164-120; 273-73