US3891211A

US3891211A - Tennis racket with interchangeable string frame

Info

Publication number: US3891211A
Application number: US479003A
Authority: US
Inventors: Peter C Diefenbach
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-06-13
Filing date: 1974-06-13
Publication date: 1975-06-24
Anticipated expiration: 1992-06-24

Abstract

A tennis racket for receiving a separate string frame consisting of a handle having a stationary bow portion integrally formed at one end thereof and a second pivotable bow portion coupled to the end of the stationary bow portion for closing to the handle and clamping the separate string frame within the bow. A groove is formed on the inside periphery of both bow portions to retain the separate string frame and a set screw secures the pivotable bow portion to the handle.

Description

United States Patent 1 1 Diefenbach 1 TENNIS RACKET WITH INTERCHANGEABLE STRING FRAME {76] Inventor: Peter C. Diefenbach, 65 South Main St., Southampton, NY. 11968 [22] Filed: June 13, 1974 [21] Appl. No; 479,003

[52] US. Cl 273/73 L [51] Int. Cl. A63B 49/02 [58] Field of Search 273/73 C, 73 E, 73 H, 73 L,

273/74; 350/309; 81/DlG 9 156] References Cited UNITED STATES PATENTS 531,795 l/1895 Green 350/309 1,407,238 2/1922 Twiss 8l/DlG. 9 UX 1454,04] 1 H1948 DeMco 350/309 IIIIIIIIIIIIIIII II/IIIIIIIIIIIIII 1 1 June 24, 1975 FOREIGN PATENTS OR APPLICATIONS 317,653 8/1929 United Kingdom 273/73 L 151.916 6/1953 Australia 273/73 L Primary E.raminer-Anton O. Oechsle Attorney, Agent or Firm-Allison C. Collard [57] ABSTRACT A tennis racket for receiving a separate string frame consisting of a handle having a stationary bow portion integrally formed at one end thereof and a second pivotable bow portion coupled to the end of the stationary bow portion for closing to the handle and clamping the separate string frame within the bow. A groove is formed on the inside periphery of both how portions to retain the separate string frame and a set screw secures the pivotable bow portion to the handle.

2 Claims, 4 Drawing Figures 1 TENNIS RACKET WITH INTERCHANGABLE STRING FRAME This invention relates to a tennis racket having an interchangable string frame.

More specifically. this invention relates to a tennis racket having a bow portion which is slotted to receive and retain a separate string frame which can be easily interchanged by the user of the racket as required.

Mos t tennis rackets whether constructed of wood or metal include a bow portion which is integrally formed with the handle of the racket. The bow includes a plurality of string-receiving openings disposed around its periphery so that the strings can be permenently affixed to the bow portion when the racket is manufactured or restrung. If a string on an expensive tennis racket breaks, the time and cost of replacing the string can sometimes cause great inconvenience as tennis rackets have to be restrung by hand either at a repair shop or sent back to the factory. Moreover, the user of the tennis racket may wish to change the type of string in the racket depending upon the type of play or action which he desires. Therefore, it is often necessary for an experienced tennis player to maintain several tennis rackets to cover all types of situations.

In the prior art, there have been constructed tennis rackets having individual bow portions which can be substituted to a common handle by means of fastening devices. In another type of tennis racket, the end of the bow frame has been opened to allow the string frame to be slidably inserted and retained in place by means of fasteners. These prior art rackets which attempt to provide interchangable string frames have been found to be costly to manufacture and not sufficiently strong to withstand impact forces during normal play.

Accordingly, the present invention provides an improved tennis racket having an interchangable string frame whereby the bow portion has been divided into two sections to include a stationary bow portion integrally formed with the handle and a pivoted bow portion which can be opened to permit the string frame to be inserted. The entire assembly is secured in place by a single set screw inserted into the throat of the tennis racket and engaging the pivoted bow portion in order to retain the string frame within an annular groove formed on the inside circumference of the bow. The pivoted portion of the bow clamps the periphery of the string frame so that the string frame is rigidly retained within the bow and does not vibrate or move during the impact forces experienced under normal play.

It is therefore an object according to the present invention to provide an improved tennis racket having an interchangeable string frame which can be easily inserted into the racket as required.

It is another object according to the present invention to provide a tennis racket having an interchangable string frame which is simple in design, inexpensive in cost and reliable during play.

Other objects and features of the present invention will become apparent from the following detailed description taken in consideration with the accompanying drawing which discloses the embodiments of the invention. It is to be understood however that the drawing is designed for the purpose of illustration only and not as a definition of the limits of the invention.

In the drawing wherein similar reference characters denote similar elements throughout the several views:

FIG. 1 is a perspective view of the tennis racket according to the invention which is opened to receive a separate string frame;

FIG. 2 is a plan view of the tennis racket according to FIG. 1 with the bow portion closed around the string frame:

FIG. 3 is a cross-sectional view taken along Section 3-3 of FIG. 2; and

FIG. 4 is a cross-sectional view taken along Section 4-4 of FIG. 2.

Referring to FIGS. l-4, there is shown the improved tennis racket according to the invention having a handle 19 extending to a throat portion 18 onto which is integrally formed a stationary bow portion 13. At the end of stationary bow portion 13 is formed a pivot 15 onto which is hinged a movable or pivoted bow portion 14 having approximately the same are distance and substantially the same shape as stationary bow 14. The inside periphery of both the stationary and pivoted bow portions includes a groove or slot 21 which is formed to receive and frictionally engage a string frame 11. String frame 11 is formed of a rigid oval hoop having a thickness corresponding to the width of groove 21. String frame 11 also includes an external groove 24 formed around its outer periphery so that strings 12 are recessed below the periphery of the frame. String frame 11 is preferably constructed of a rigid material such as metal so that it is capable of receiving strings 12 under tension without deforming. warping or collapsing. Its

oval construction provides the string frame with an in-' herent strength to resist the tension applied by the.

strings around its periphery.

The ends of the bow portions are hinged together as shown in detail in FIG. 3. A pivot pin or rivet l5engages through two extending arms formedht the end of stationary bow l3 and also engages affifojecting arm 23 of pivoted bow portion 1 4.-Rivet or pin 15 can be swaged at its ends so that it'will remain permanently engaged in stationary bow portion l3."Pivoted bow portion 14 can then be openedfsufticiently wide to permit string frame 11 to be removedfrom the groove formed in stationary bow portion 13 and interchanged with a new string frame.

The free end of pivoted bow portion 14 includes a projecting flange 22 which is adapted to engage a corresponding channel formed at the base of stationary bow portion 13 adjacent to the throat of the racket, as shown in detail in FIG. 4. This end of pivoted bow portion 14 also includes a threaded hole 26 so that a set screw 20 can be inserted through bore 17 in bow portion 13 and engage the threaded hole 26. Flange 22 formed at the end of pivoted bow portion 14 maintains the alignment of the pivoted bow portion with the stationary bow portion and the throat of the racket. The base of bow portion 13 is formed with an inclined portion 27 forming an acute angle with respect to the longitudinal axis of handle 19. Set screw 20 permits the pivoted bow portion to be tightened around string frame 11 so that the string frame is effectively clamped between stationary bow portion 13 and pivoted bow portion 14. This prevents string frame 11 from any movement or vibration in the bow of the racket during the impact of the tennis ball under normal play. The end of said screw 20 may include a normal screw slot for receiving a screw driver or a hexagonal slot for receiving a standard Allen head wrench.

The tennis racket according to the present invention may be constructed of any rigid materials such as wood. metal or plastic. String frame 11 should be constructed to have an external diameter or oval circumference slightly larger than the circumference of groove 21 so that the string frame can be effectively clamped within the two portions of the how when set screw is tightened. String frame 11 is constructed so that strings 12 can be inserted by machine rather than by hand and marketed as a replacement item at relatively low cost.

While only a single embodiment of the present invention has been shown and described it will be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.

What is claimed is:

l. A tennis racket comprising:

a first bow portion having a base at one end:

a handle including a throat portion and having said base of said first bow portion integrally formed on said throat portion;

a second bow portion pivotally coupled to said first bow portion at another end thereof;

an annular and continuous groove formed on the inside periphery of said first and second bow portions;

a string frame removeably disposed in said groove:

said base having an arcuate inner periphery extending continuously with that of said first bow portion and abutting said string frame. said base having a lateral side formed with a straight inclined portion forming an acute angle with respect to the longitudinal axis of said handle, said inclined portion being formed with a central channel extending along its length;

said second bow portion having a free end formed with an inclined edge and having a central projecting flange extending therefrom along its length. said inclined edge and said projecting flange complementary fitting together with said inclined portion and said central channel, respectively, of said base of said first bow portion in a closed position. said second bow portion having an arcuate inner periphery extending continuously from that of said base portion in said closed position and abutting said string frame, said base and said free end of said second bow portion being formed with a hole extending perpendicularly to the longitudinal axis of said handle and through said projecting flange with that portion of the hole in the second bow portion being threaded; and

a set screw disposed in said hole for releasably threadably coupling said base and said free end in said closed position.

2. The tennis racket according to claim 1, wherein said hole includes a counterbore in the base for receiving the head of said set screw.

Claims

1. A tennis racket comprising: a first bow portion having a base at one end; a handle including a throat portion and having said base of said first bow portion integrally formed on said throat portion; a second bow portion pivotally coupled to said first bow portion at another end thereof; an annular and continuous groove formed on the inside periphery of said first and second bow portions; a string frame removeably disposed in said groove; said base having an arcuate inner periphery extending continuously with that of said first bow portion and abutting said string frame, said base having a lateral side formed with a straight inclined portion forming an acute angle with respect to the longitudinal axis of said handle, said inclined portion being formed with a central channel extending along its length; said second bow portion having a free end formed with an inclined edge and having a central projecting flange extending therefrom along its length, said inclined edge and said projecting flange complementary fitting together with said inclined portion and said central channel, respectively, of said base of said first bow portion in a closed position, said second bow portion having an arcuate inner periphery extending continuously from that of said base portion in said closed position and abutting said string frame, said base and said free end of said second bow portion being formed with a hole extending perpendicularly to the longitudinal axis of said handle and through said projecting flange with that portion of the hole in the second bow portion being threaded; and a set screw disposed in said hole for releasably threadably coupling said base and said free end in said closed position.